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PT Journal
AU Pringle, CM
TI Hydrologic connectivity and the management of biological
   reserves: A global perspective
SO ECOLOGICAL APPLICATIONS
AB Increasingly, biological reserves throughout the world are
   threatened by cumulative alterations in hydrologic connectivity
   within the greater landscape. Hydrologic connectivity is used
   here in an ecological sense to refer to water-mediated transfer
   of matter, energy, and/or organisms within or between elements
   of the hydrologic cycle. Obvious human influences that alter
   this property include dams, associated flow regulation,
   groundwater extraction, and water diversion, all of which can
   result in a cascade of events in both aquatic and terrestrial
   ecosystems. Even disturbances well outside the boundaries of
   reserves can have profound effects on the biological integrity
   of these "protected" areas. Factors such as nutrient and toxic
   pollution and the spread of normative species are perpetuated
   by hydrologic connectivity, and their effects can be
   exacerbated by changes in this property. Hydrological
   alterations are now affecting reserves through increasingly
   broad feedback loops, ranging from overdrawn aquifers to
   atmospheric deposition and global climate change. Such
   alterations are often beyond the direct control of managers
   because they lie outside reserve boundaries, and data on
   hydrologic connection between reserves and surrounding
   landscapes are scant. The subject of water has also been
   typically excluded from the literature pertaining to both
   theoretical and practical aspects of reserve size, isolation,
   and design. This results, in part, from early management
   strategies developed when the landscape matrix outside of
   reserves was not excessively fragmented, and when awareness of
   hydrologic connectivity was in its infancy. The location of a
   given reserve within a watershed, relative to regional aquifers
   and wind and precipitation patterns, can play a key role in its
   response to human disturbance transmitted through the
   hydrologic cycle. To illustrate this point, I discuss reserves
   of varying sizes from diverse regions throughout the world.
   Reserves located in middle and lower watersheds often suffer
   direct hydrologic alterations that cause severe habitat
   modification and exacerbate the effects of pollution. In
   contrast, reserves in upper watersheds may have intact physical
   habitat and contain important source populations of some native
   biota, yet hydrologic disturbances in lower watersheds may
   cause extirpation of migratory species, cascading trophic
   effects, and genetic isolation. Worldwide, <7% of land area is
   either strictly or partially protected, and many reserves are
   in danger of becoming population "sinks" for wildlife if we do
   not develop a more predictive understanding of how they are
   affected by hydrologic alterations that originate outside of
   their boundaries.
BP 981
EP 998
PG 18
JI Ecol. Appl.
PY 2001
PD AUG
VL 11
IS 4
GA 458RW
J9 ECOL APPL
UT ISI:000170209200004
ER

PT Journal
AU Jackson, RB
   Carpenter, SR
   Dahm, CN
   McKnight, DM
   Naiman, RJ
   Postel, SL
   Running, SW
TI Water in a changing world
SO ECOLOGICAL APPLICATIONS
AB Renewable fresh water comprises a tiny fraction of the global
   water pool but is the foundation for life in terrestrial and
   freshwater ecosystems. The benefits to humans of renewable
   fresh water include water for drinking, irrigation, and
   industrial uses, for production of fish and waterfowl, and for
   such instream uses as recreation, transportation, and waste
   disposal. In the coming century, climate change and a growing
   imbalance among freshwater supply, consumption, and population
   will alter the water cycle dramatically. Many regions of the
   world are already limited by the amount and quality of
   available water. In the next 30 yr alone, accessible runoff is
   unlikely to increase more than 10%, but the earth's population
   is projected to rise by approximately one-third. Unless the
   efficiency of water use rises, this imbalance will reduce
   freshwater ecosystem services, increase the number of aquatic
   species facing extinction, and further fragment wetlands,
   rivers, deltas, and estuaries. Based on the scientific evidence
   currently available, we conclude that: (1) over half of
   accessible freshwater runoff globally is already appropriated
   for human use; (2) more than 1 x 10(9) people currently lack
   access to clean drinking water and almost 3 x 10(9) people lack
   basic sanitation services; (3) because the human population
   will grow faster than increases in the amount of accessible
   fresh water, per capita availability of fresh water will
   decrease in the coming century; (4) climate change will cause a
   general intensification of the earth's hydrological cycle in
   the next 100 yr, with generally increased precipitation,
   evapotranspiration, and occurrence of storms, and significant
   changes in biogeochemical processes influencing water quality;
   (5) at least 90% of total water discharge from U.S. rivers is
   strongly affected by channel fragmentation from dams,
   reservoirs, interbasin diversions, and irrigation; and (6)
   globally, 20% of freshwater fish species are threatened or
   extinct, and freshwater species make up 47% of all animals
   federally endangered in the United States. The growing demands
   on freshwater resources create an urgent need to link research
   with improved water management. Better monitoring, assessment,
   and forecasting of water resources will help to allocate water
   more efficiently among competing needs, Currently in the United
   States, at least six federal departments and 20 agencies share
   responsibilities for various aspects of the hydrologic cycle.
   Coordination by a single panel with members drawn from each
   department, or by a central agency, would acknowledge the
   diverse pressures on freshwater systems and could lead to the
   development of a well-coordinated national plan.
BP 1027
EP 1045
PG 19
JI Ecol. Appl.
PY 2001
PD AUG
VL 11
IS 4
GA 458RW
J9 ECOL APPL
UT ISI:000170209200008
ER

PT Journal
AU Berndes, G
   Azar, C
   Kaberger, T
   Abrahamson, D
TI The feasibility of large-scale lignocellulose-based bioenergy
   production
SO BIOMASS & BIOENERGY
AB Global, large-scale use of bioenergy may replace a significant
   part of present fossil fuel use. We show that labor
   availability and water resources are large compared to those
   required to operate a bioenergy system of such size. The
   present study contradicts the assertion by Giampietro et al.
   [Bioscience 47(9) (1997) 587], that labor and water
   availability provide invincible barriers to a large-scale use
   of biofuels. We examine water and labor requirements under more
   reasonable assumptions about bioenergy supply options and
   demand levels. Bioenergy supplies are based on dedicated
   plantations of lignocellulosic crops and bioenergy demand is
   based on the renewable intensive global energy scenarios
   (RIGES). We find that labor and water requirements are an order
   of magnitude lower than the estimates by Giampietro et al. For
   instance, labor requirements do not exceed 1 percent of the
   estimated total work force in any country. (C) 2001 Elsevier
   Science Ltd. All rights reserved.
BP 371
EP 383
PG 13
JI Biomass Bioenerg.
PY 2001
VL 20
IS 5
GA 435MY
J9 BIOMASS BIOENERG
UT ISI:000168886300006
ER

PT Journal
AU Postel, SL
TI Water and world population growth
SO JOURNAL AMERICAN WATER WORKS ASSOCIATION
AB Freshwater is renewable but finite. Over the next 50 years,
   world population growth will reduce the renewable water supply
   per capita by approximately one third. By 2025, an estimated 3
   billion people - 38 percent of the projected global population
   - will live in countries classified as water-stressed. In many
   regions, numerous signs that water use is not sustainable are
   already in evidence in the widespread overpumping of aquifers
   and excessive depletion of river flows. Meeting the water
   demands of 8 - 9 billion people while at the same time
   protecting the health of the aquatic environment will greatly
   challenge water professionals. This article makes the case for
   a new water management paradigm - one that strives to balance
   water's economic and ecological functions. A key to success is
   increasing water productivity, i.e., doing more with less
   water.
BP 131
EP 138
PG 8
JI J. Am. Water Work Assoc.
PY 2000
PD APR
VL 92
IS 4
GA 434VB
J9 J AMER WATER WORK ASSN
UT ISI:000168835600019
ER

PT Journal
AU Rockstom, J
TI Green water security for the food makers of tomorrow: windows
   of opportunity in drought-prone savannahs
SO WATER SCIENCE AND TECHNOLOGY
AB The largest remaining biophysical water challenge is whether
   there is enough fresh water to sustain global food production
   and service natural ecosystems. Focussing on the drought-prone
   savannahs and small-scale farming, this paper argues that the
   crucial resource is vapour flow, not "blue" water, and there
   are grounds for optimism if resource management can be
   improved.
BP 71
EP 78
PG 8
JI Water Sci. Technol.
PY 2001
VL 43
IS 4
GA 420YA
J9 WATER SCI TECHNOL
UT ISI:000168031800014
ER

PT Journal
AU Tilman, D
   Fargione, J
   Wolff, B
   D'Antonio, C
   Dobson, A
   Howarth, R
   Schindler, D
   Schlesinger, WH
   Simberloff, D
   Swackhamer, D
TI Forecasting agriculturally driven global environmental change
SO SCIENCE
AB During the next 50 years, which is likely to be the final
   period of rapid agricultural expansion, demand for food by a
   wealthier and 50% Larger global population will be a major
   driver of global environmental change. Should past dependences
   of the global environmental impacts of agriculture on human
   population and consumption continue, 10(9) hectares of natural
   ecosystems would be converted to agriculture by 2050. This
   would be accompanied by 2.4- to 2.7-fold increases in nitrogen-
   and phosphorus-driven eutrophication of terrestrial,
   freshwater, and near-shore marine ecosystems, and comparable
   increases in pesticide use. This eutrophication and habitat
   destruction would cause unprecedented ecosystem simplification,
   Loss of ecosystem services, and species extinctions.
   Significant scientific advances and regulatory, technological,
   and policy changes are needed to control the environmental
   impacts of agricultural expansion.
BP 281
EP 284
PG 4
JI Science
PY 2001
PD APR 13
VL 292
IS 5515
GA 421QA
J9 SCIENCE
UT ISI:000168074000045
ER

PT Journal
AU Varis, O
TI The Nile Basin in a global perspective - Natural, human, and
   socioeconomic resource nexus
SO WATER INTERNATIONAL
AB The Nile brings virtually no water to the sea. The mighty basin
   with 1/10 of Africa's land area and 1/3 of its population, has
   only 1/16 of its water. The riparian countries use practically
   all of the Nile's water and they face increasing challenges in
   terms of environmental degradation, food security. and
   socioeconomic development. The geopolitical situation blocks
   the integrated de,development of water resources in the basin
   scale, yet the political environment may be improving. The Nile
   basin is among the most critical regions of the world in terms
   of water resources development. In this article, the trend's of
   the major driving forces within the basin countries-population,
   urbanization, climate, agriculture. economy human resources,
   and governance-are scrutinized from the viewpoint of their
   impacts on water resources and their management. A comparison
   is made to our other critical macroregions. China, South Asia.
   Southeast Asia, and West Africa.
BP 624
EP 637
PG 14
JI Water Int.
PY 2000
PD DEC
VL 25
IS 4
GA 408JC
J9 WATER INT
UT ISI:000167322200015
ER

PT Journal
AU Schroeder, JI
   Kwak, JM
   Allen, GJ
TI Guard cell abscisic acid signalling and engineering drought
   hardiness in plants
SO NATURE
AB Guard cells are located in the epidermis of plant leaves, and
   in pairs surround stomatal pores. These control both the influx
   of CO2 as a raw material for photosynthesis and water loss from
   plants through transpiration to the atmosphere. Guard cells
   have become a highly developed system for dissecting early
   signal transduction mechanisms in plants. In response to
   drought, plants synthesize the hormone abscisic acid, which
   triggers closing of stomata, thus reducing water loss.
   Recently, central regulators of guard cell abscisic acid
   signalling have been discovered. The molecular understanding of
   the guard cell signal transduction network opens possibilities
   for engineering stomatal responses to control CO2 intake and
   plant water loss.
BP 327
EP 330
PG 4
JI Nature
PY 2001
PD MAR 15
VL 410
IS 6826
GA 410WM
J9 NATURE
UT ISI:000167464100038
ER

PT Journal
AU Wolter, C
TI Conservation of fish species diversity in navigable waterways
SO LANDSCAPE AND URBAN PLANNING
AB Nineteen waterways in the German lowlands were surveyed between
   1992 and 1997 to evaluate their fishes conservation capacity.
   From 277 sites a total of 84 821 fish of 31 species was
   collected. Number of species in various waterways ranged from 6
   to 26 with a mean +/- standard deviation of 15.4 +/- 5.4. Mean
   species diversity was H' = 1.61 +/- 0.29 (range 1.02-2.20), and
   corresponding evenness 0.61 +/- 0.09 (0.51-0.76). Fish
   communities of waterways were dominated by perch and roach,
   both contributing in mean 68.5 +/- 12.5% to the total catch.
   The mean relative abundance of threatened fish listed in "Red
   Data Books" of Germany or Europe was 7.83 +/- 4.82%. Percentage
   of artificial shoreline structures like riprap or sheet pile
   wall was inversely correlated to species number, species
   diversity and abundance of intolerant species. This study was a
   first approach to estimate the percentage of habitat
   restoration required to increase species diversity. Even the
   restoration of one-fifth of the river banks, the restoration of
   natural shoreline structures from close 0 to 20% of the
   bankline should result in substantial improvement of fish
   diversity, and significantly contribute to species conservation
   and persistence of viable populations of threatened fishes in
   waterways. In regard to such relatively low restoration effort,
   biodiversity conservation in waterways is compatible with long-
   term resource use, navigation and human needs. Even though
   heavily modified, waterways are also recommended for
   conservation issues by their large area covered as well as
   their substantial number of fish species. (C) 2001 Elsevier
   Science B.V. All rights reserved.
BP 135
EP 144
PG 10
JI Landsc. Urban Plan.
PY 2001
PD JAN 30
VL 53
IS 1-4
GA 404UT
J9 LANDSCAPE URBAN PLAN
UT ISI:000167120700011
ER

PT Journal
AU Putz, FE
   Blate, GM
   Redford, KH
   Fimbel, R
   Robinson, J
TI Tropical forest management and conservation of biodiversity: an
   overview
SO CONSERVATION BIOLOGY
BP 7
EP 20
PG 14
JI Conserv. Biol.
PY 2001
PD FEB
VL 15
IS 1
GA 405QK
J9 CONSERV BIOL
UT ISI:000167170400004
ER

PT Journal
AU Likens, GE
TI Biogeochemistry, the watershed approach: some uses and
   limitations
SO MARINE AND FRESHWATER RESEARCH
AB The watershed (catchment) approach provides a powerful
   conceptual model for quantitatively evaluating the structure,
   function and change within a landscape or region. The values
   and limitations of this approach are considered in this paper,
   with particular reference to the Hubbard Brook watershed-
   ecosystem model. The need for informed long-term (sustained)
   research is stressed; a haphazard collection of data is rarely
   valuable. Team-building efforts will be needed increasingly in
   the future to enhance the success of multidisciplinary teams
   tackling large and complex environmental problems.
BP 5
EP 12
PG 8
JI Mar. Freshw. Res.
PY 2001
VL 52
IS 1
GA 399DD
J9 MAR FRESHWATER RES
UT ISI:000166795200002
ER

PT Journal
AU Pace, ML
TI Prediction and the aquatic sciences
SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES
AB The need for prediction is now widely recognized and frequently
   articulated as an objective of research programs in aquatic
   science. This recognition is partly the legacy of earlier
   advocacy by the school of empirical limnologists. This school,
   however, presented prediction narrowly and failed to account
   for the diversity of predictive approaches as well to set
   prediction within the proper scientific context. Examples from
   time series analysis and probabilistic models oriented toward
   management provide an expanded view of approaches and prospects
   for prediction. The context and rationale for prediction is
   enhanced understanding. Thus, prediction is correctly viewed as
   an aid to building scientific knowledge with better
   understanding leading to improved predictions. Experience,
   however, suggests that the most effective predictive models
   represent condensed models of key features in aquatic systems.
   Prediction remains important for the future of aquatic
   sciences. Predictions are required in the assessment of
   environmental concerns and for testing scientific fundamentals.
   Technology is driving enormous advances in the ability to study
   aquatic systems. If these advances are not accompanied by
   improvements in predictive capability, aquatic research will
   have failed in delivering on promised objectives. This
   situation should spark discomfort in aquatic scientists and
   foster creative approaches toward prediction.
BP 63
EP 72
PG 10
JI Can. J. Fish. Aquat. Sci.
PY 2001
PD JAN
VL 58
IS 1
GA 390AG
J9 CAN J FISHERIES AQUAT SCI
UT ISI:000166270400007
ER

PT Journal
AU Wahlgren, RV
TI Atmospheric water vapour processor designs for potable water
   production: A review
SO WATER RESEARCH
AB Atmospheric water vapour processing (AWVP) technology is
   reviewed. These processors are machines which extract water
   molecules from the atmosphere, ultimately causing a phase
   change from vapour to liquid. Three classes of machines have
   been proposed. The machines either cool a surface below the
   dewpoint of the ambient air, concentrate water vapour through
   use of solid or liquid desiccants, or induce and control
   convection in a tower structure. Patented devices vary in scale
   and potable water output from small units suitable for one
   person's daily needs to structures as large as multi-story
   office buildings capable of supplying drinking water to an
   urban neighbourhood. Energy and mass cascades (flowcharts) are
   presented for the three types of water vapour processors. The
   flowcharts assist in classifying designs and discussing their
   strengths and limitations. Practicality and appropriateness of
   the various designs for contributing to water supplies are
   considered along with water cost estimates. Prototypes that
   have been tested successfully are highlighted. Absolute
   humidity (meteorological normals) ranges from 4.0 g of water
   vapour per cubic metre of surface air in the atmosphere (Las
   Vegas, Nevada, USA) to 21.2 g m(-3) (Djibouti, Republic of
   Djibouti). Antofagasta, Chile has a normal absolute humidity of
   10.9 g m(-3). A 40% efficient machine in the vicinity of
   Antofagasta requires an airflow of IO m(3) s(-1) to produce
   3767 1 of water per day. At a consumption of 50 1 per person
   per day, 75 people could have basic water requirements for
   drinking, sanitation, bathing, and cooking met by a
   decentralized and simplified water supply infrastructure with
   attendant economic and societal benefits. (C) 2000 Elsevier
   Science Ltd. All rights reserved.
BP 1
EP 22
PG 22
JI Water Res.
PY 2001
PD JAN
VL 35
IS 1
GA 381UN
J9 WATER RES
UT ISI:000165782000001
ER

PT Journal
AU Vorosmarty, CJ
   Fekete, BM
   Meybeck, M
   Lammers, RB
TI Geomorphometric attributes of the global system of rivers at
   30-minute spatial resolution
SO JOURNAL OF HYDROLOGY
AB In this paper we explore the geomorphometric characteristics
   and integrity of a 30' (longitude x latitude) spatial
   resolution representation of the global system of potentially-
   flowing rivers. We quantify several geomorphometric attributes
   of digital, Simulated Topological Network (STN-30p) depicting
   potential flow pathways across the entire non-glacierized
   surface of the Earth. This data set was examined with respect
   to several metrics describing individual grid cells, river
   segments, and complete drainage systems. Nearly 60,000 grid
   cells constitute the global non-glacierized land mass. The
   cells are organized into more than 30,000 distinct river
   segments belonging to approximately 6200 drainage basins. STN-
   30p flow paths and drainage basins are classified as order one
   through six using the classification system of Strahler. STN-
   30p flow pathways depict rivers draining a global land area of
   133.1 x 10(6) km(2). These pathways show a total length of 3.24
   x 10(6) km at 30' spatial resolution. The relationships between
   STN-30p order and interior river segment numbers, accumulated
   sub-basin areas, and accumulated length within individual
   basins yield high correlation coefficients (average r(2) > 0.96
   for continents and globe). Mean values across individual
   continents and river orders for the bifurcation ratio (3.15 to
   4.44), drainage area ratio (3.74 to 5.77), and basin length
   ratio (2.02 to 3.27) fall well within the ranges tabulated at
   finer spatial scales. A basin shape index, S-b = L/A(0.5),
   defined as a function of potential mainstem length and drainage
   area, varies between 1.0 and 5.0 for basins >25,000 km(2) and
   shows a global mean of 2.12. The structure of STN-30p potential
   river systems is consistent with those of rivers analyzed at
   finer spatial scales as demonstrated by the numerical
   similarity of the several geomorphometric indices analyzed.
   However, for a particular basin, indices from STN-30p will be
   based on a condensed set of river orders relative to those
   derived at finer scales. A first order STN-30p river is roughly
   equivalent to an order five-to-six river derived from 1:62,500
   scale maps. While 30' spatial resolution was found to represent
   well the 522 basins with areas >25,000 km(2) that drain 82% of
   the land mass, it cannot be used with high confidence in
   characterizing the geomorphometry of the remaining smaller
   basins. For global climate and biogeochemical studies, a
   composite of the 30' resolution and finer spatial resolutions
   appears to be necessary. (C) 2000 Elsevier Science B.V. All
   rights reserved.
BP 17
EP 39
PG 23
JI J. Hydrol.
PY 2000
PD OCT 25
VL 237
IS 1-2
GA 366WR
J9 J HYDROL
UT ISI:000090029700002
ER

PT Journal
AU Rosenberg, DM
   McCully, P
   Pringle, CM
TI Global-scale environmental effects of hydrological alterations:
   Introduction
SO BIOSCIENCE
BP 746
EP 751
PG 6
JI Bioscience
PY 2000
PD SEP
VL 50
IS 9
GA 353AK
J9 BIOSCIENCE
UT ISI:000089251400005
ER

PT Journal
AU Vorosmarty, CJ
   Sahagian, D
TI Anthropogenic disturbance of the terrestrial water cycle
SO BIOSCIENCE
BP 753
EP 765
PG 13
JI Bioscience
PY 2000
PD SEP
VL 50
IS 9
GA 353AK
J9 BIOSCIENCE
UT ISI:000089251400006
ER

PT Journal
AU Smith, JV
TI Natural hazards: Geology, engineering, agriculture, and
   sociopolitical/humanitarian considerations for the twenty-first
   century
SO INTERNATIONAL GEOLOGY REVIEW
AB Dangers from natural hazards have been characterized
   quantitatively by national and international committees of
   geoscientists based on technical advances in geochemistry and
   geophysics (sensu lato). The current status of knowledge on
   natural hazards is reviewed with particular emphasis on
   comet/asteroid impact, earthquakes, and volcanoes. All these
   hazards are survivable by the world's population if appropriate
   measures are taken over the next century and millennium. Ideas
   for mitigation include: general use of weathered volcanic ash
   and power-station fly ash to make pozzolana cement for
   strengthening buildings, and stabilizing weak ground and
   hillsides prone to slumping; long-term storage of grains under
   nitrogen, together with other techniques for maintaining
   viability of stored food; drilling of tunnels under major
   cities to facilitate traffic flow, and for protection against
   impact of bolides and bombs; design of sea and lake fronts to
   guard against tsunamis from earthquakes and asteroid impact.
   The food-storage proposals could be tailored to help farmers
   obtain a regular income while producing a higher crop yield
   than needed for current food supply. The land modification
   plans would provide technical challenges and new business
   activities for civil engineers, lawyers, real-estate
   professionals, and city planners. It is truly tragic that
   genuine ideas for mitigation of natural hazards are being
   implemented at a snail's pace while funding for weapons
   nourishes around much of the world. The early development of my
   thinking on hazards is an example of the typical disconnection
   between "scientific expertise" and actual day-to-day planning
   decisions. As a farmer's boy interested in civil engineering
   and land planning in an ecological context, I summarize old and
   new ideas in an effort to bridge this disconnection, and
   facilitate the planned transfer of funding from weapons to
   actions that enhance human well being. Because the actions are
   international in their basic nature and ecological in
   character, I hope that they will help to generate a feeling of
   "One world that must be loved, not abused." We belong to one
   biological species, Homo supposedly sapiens sapiens. We must
   progress beyond tribal, ethnic, and other divisive matters
   associated with wars and civilian conflicts. The rich must help
   the poor. Geology and civil engineering can provide important
   worldwide cooperative connections.
BP 617
EP 656
PG 40
JI Int. Geol. Rev.
PY 2000
PD JUL
VL 42
IS 7
GA 342VW
J9 INT GEOL REV
UT ISI:000088666700003
ER

PT Journal
AU Kingsford, RT
TI Protecting rivers in arid regions or pumping them dry?
SO HYDROBIOLOGIA
BP 1
EP 11
PG 11
JI Hydrobiologia
PY 2000
PD JUN 1
VL 427
IS 1-3
GA 341FJ
J9 HYDROBIOLOGIA
UT ISI:000088580100001
ER

PT Journal
AU Postel, SL
TI Entering an era of water scarcity: The challenges ahead
SO ECOLOGICAL APPLICATIONS
AB Fresh water is a renewable resource, but it is also finite.
   Around the world, there are now numerous signs that human water
   use exceeds sustainable levels. Groundwater depletion, low or
   nonexistent river flows, and worsening pollution levels are
   among the more obvious indicators of water stress. In many
   areas, extracting more water for human uses jeopardizes the
   health of vital aquatic ecosystems. Satisfying the increased
   demands for food, water, and material goods of a growing global
   population while at the same time protecting the ecological
   services provided by natural water ecosystems requires new
   approaches to using and managing fresh water. In this article,
   I propose a global effort (1) to ensure that freshwater
   ecosystems receive the quantity, quality, and timing of flows
   needed for them to perform their ecological functions and (2)
   to work toward a goal of doubling water productivity. Meeting
   these challenges will require policies that promote rather than
   discourage water efficiency, as well as new partnerships that
   cross disciplinary and professional boundaries.
BP 941
EP 948
PG 8
JI Ecol. Appl.
PY 2000
PD AUG
VL 10
IS 4
GA 339UJ
J9 ECOL APPL
UT ISI:000088496000002
ER

PT Journal
AU Naiman, RJ
   Turner, MG
TI A future perspective on North America's freshwater ecosystems
SO ECOLOGICAL APPLICATIONS
AB Fresh waters are central to society and to the environment.
   Nevertheless, ongoing and projected changes in the
   distribution, abundance, and quality of water resources and
   freshwater ecosystems represent a serious threat to the
   integrity of the environment as well as the vitality of human
   cultures. Nearly every country in the world experiences regular
   water shortages, agriculture uses most of the world's available
   fresh water, and most illnesses in developing countries result
   from waterborne parasites and pathogens. Unfortunately, often
   hidden in these and other depressing statistics are the needs
   of the environment for adequate water to maintain vibrant
   ecosystems. Understanding the abilities and limits of
   freshwater ecosystems to respond to human-generated pressures
   is becoming a central issue for cultures and a challenge for
   science. This article explores trends in alterations to
   freshwater ecosystems, discusses the ecological consequences of
   biophysical alterations expected to occur in the next 20-30
   years, and identifies some of the major scientific challenges
   and opportunities to effectively address the changes. Topics
   discussed include altered hydrological regimes, biogeochemical
   cycles, altered land use, riparian management, life history
   strategies, and relations between climate change and water
   resource management.
BP 958
EP 970
PG 13
JI Ecol. Appl.
PY 2000
PD AUG
VL 10
IS 4
GA 339UJ
J9 ECOL APPL
UT ISI:000088496000004
ER

PT Journal
AU Pringle, CM
TI Threats to US public lands from cumulative hydrologic
   alterations outside of their boundaries
SO ECOLOGICAL APPLICATIONS
AB U.S. public lands are increasingly threatened by human
   alteration of hydrologic connections outside their boundaries.
   Cumulative effects of dams, impoundments, regulated flows,
   wetlands drainage, and groundwater extraction outside of public
   land boundaries can play a key role in controlling the
   hydrology and biology within these managed areas. Expanding
   human populations require more water, and they often look to
   public lands to meet their demands. Immediate challenges facing
   water resource managers are increased pressure to dam rivers
   and pump aquifers near public lands, as a result of water
   shortages exacerbated by droughts coupled with increased
   demands from municipal and agricultural growth. As pollutants
   become more concentrated in less water, water quality often
   becomes a major related issue. While these problems are
   particularly acute in rapidly growing regions of the arid West
   where water is severely limited, they are also emerging in the
   East. Data on cumulative effects of hydrologic alterations on
   the biological integrity of public lands have not been
   systematically assessed at a national level. However, emerging
   trends can be used to gauge the magnitude of outside pressures
   and to place water resource challenges into context. The U.S.
   National Park Service is participating in water rights
   adjudications in over 50 different park service units. The U.S.
   Forest Service currently has over 500 legal claims concerning
   water rights for national forests located in 55 basins of 11
   Western states. Similar conflicts exist for national wildlife
   refuges which are particularly vulnerable to water quality and
   quantity problems because of their small size; in 1994, 150 out
   of 224 Western wildlife refuges reported conflicts with other
   water users, and only 98 reported that their existing water
   rights assured delivery of adequate water in an average year.
   As human demands for water continue to expand, financially
   strapped federal land management agencies have a greater need
   for strengthened institutional, legal, and scientific tools to
   manage hydrologic connections. Two case studies from different
   biogeographic extremes (Stillwater National Wildlife Refuge in
   the arid Nevada desert and the Caribbean National Forest in the
   wet tropics of Puerto Rico) illustrate the synergism that can
   occur between field managers and scientists in implementing
   localized solutions. Moreover, they highlight the critical need
   to address cumulative long-term effects of hydrologic
   alterations outside of public land boundaries. Recommendations
   include: establishment of more stream gaging stations and
   monitoring programs within and adjacent to public lands;
   development of new and innovative partnerships between federal
   land management agencies and both federal and academic
   scientists; and interdisciplinary research and development of
   science-based tools to predict cumulative and interactive
   effects of hydrologic alterations.
BP 971
EP 989
PG 19
JI Ecol. Appl.
PY 2000
PD AUG
VL 10
IS 4
GA 339UJ
J9 ECOL APPL
UT ISI:000088496000005
ER

PT Journal
AU Gordon, L
   Folke, C
TI Ecohydrological landscape management for human well-being
SO WATER INTERNATIONAL
AB This paper introduces a new perspective on water resources
   emphasizing the role of water vapor flows for human well-being.
   The connections between freshwater and ecosystem services in
   terrestrial environments are addressed, particularly the role
   of freshwater for the biota that sustains the flow of ecosystem
   services and the role of the biota that modifies freshwater
   flows. First, the water dependence of terrestrial ecosystem
   sewices and food production are analyzed. Secondly, two
   examples of unintentional, large-scale, water-mediated
   cascading effects related to ecosystem services that result
   from local, uncoordinated decisions in Australia and South
   Africa are discussed These two countries are taking the lead in
   the management of freshwater flows and terrestrial ecosystem
   services. Issues including potential conflicts of interest and
   trade-offs between food (or timber) production and ecosystem
   sewices at the catchment scale are taken into account. A world-
   wine, intentional ecohydrological landscape approach to handle
   these issues is suggested. One important step towards a more
   integrated approach to freshwater is the development of
   flexible institutional structures.
BP 178
EP 184
PG 7
JI Water Int.
PY 2000
PD JUN
VL 25
IS 2
GA 335PY
J9 WATER INT
UT ISI:000088253800004
ER

PT Journal
AU Vorosmarty, CJ
   Green, P
   Salisbury, J
   Lammers, RB
TI Global water resources: Vulnerability from climate change acid
   population growth
SO SCIENCE
AB The future adequacy of freshwater resources is difficult to
   assess, owing to a complex and rapidly changing geography of
   water supply and use. Numerical experiments combining climate
   model outputs, water budgets, and socioeconomic information
   along digitized river networks demonstrate that (i) a large
   proportion of the world's population is currently experiencing
   water stress and (ii) rising water demands greatly outweigh
   greenhouse warming in defining the state of global water
   systems to 2025. Consideration of direct human impacts on
   global water supply remains a poorly articulated but
   potentially important facet of the larger global change
   question.
BP 284
EP 288
PG 5
JI Science
PY 2000
PD JUL 14
VL 289
IS 5477
GA 334DB
J9 SCIENCE
UT ISI:000088169400037
ER

PT Journal
AU Vorosmarty, CJ
   Fekete, BM
   Meybeck, M
   Lammers, RB
TI Global system of rivers: Its role in organizing continental
   land mass and defining land-to-ocean linkages
SO GLOBAL BIOGEOCHEMICAL CYCLES
AB The spatial organization of the Earth's land mass is analyzed
   using a simulated topological network (STN-30p) representing
   potential flow pathways across the entire nonglacierized
   surface of the globe at 30-min (longitude x latitude) spatial
   resolution. We discuss a semiautomated procedure to develop
   this topology combining digital elevation models and manual
   network editing. STN-30p was verified against several
   independent sources including map products and drainage basin
   statistics, although we found substantial inconsistency within
   the extant literature itself. A broad suite of diagnostics is
   offered that quantitatively describes individual grid cells,
   river segments, and complete drainage systems spanning orders 1
   through 6 based on the Strahler classification scheme.
   Continental and global-scale summaries of key STN-30p
   attributes are given. Summaries are also presented which
   distinguish basins that potentially deliver discharge to an
   ocean (exorheic) from those that potentially empty into an
   internal receiving body (endorheic). A total of 59,122
   individual grid cells constitutes the global nonglacierized
   land mass. At 30-min spatial resolution, the cells are
   organized into 33,251 distinct river segments which define 6152
   drainage basins. A global total of 133.1 x 10(6) km(2) bear
   STN-30p flow paths with a total length of 3.24 x 106 km. The
   organization of river networks has an important role in linking
   land mass to ocean. From a continental perspective, low-order
   river segments (orders 1-3) drain the largest fraction of land
   (90%) and thus constitute a primary source area for runoff and
   constituents. From an oceanic perspective, however, the small
   number (n = 101) of large drainage systems (orders 4-6)
   predominates; draining 65% of global land area and subsuming a
   large fraction of the otherwise spatially remote low-order
   rivers. Along river corridors, only 10% of land mass is within
   100 km of a coastline, 25% is within 250 km, and 50% is within
   750 km. The global mean distance to river mouth is 1050 km with
   individual continental values from 460 to 1340 km. The
   Mediterranean/Black Sea and Arctic Ocean are the most land-
   dominated of all oceans with land:ocean area ratios of 4.4 and
   1.2, respectively; remaining oceans show ratios from 0.55 to
   0.13. We discuss limitations of the STN-30p together with its
   potential role in future global change studies. STN-30p is
   geographically linked to several hundred river discharge and
   chemistry monitoring stations to provide a framework for
   calibrating and validating macroscale hydrology and
   biogeochemical flux models.
BP 599
EP 621
PG 23
JI Glob. Biogeochem. Cycle
PY 2000
PD JUN
VL 14
IS 2
GA 323VR
J9 GLOBAL BIOGEOCHEM CYCLE
UT ISI:000087586100007
ER

PT Journal
AU Murdoch, PS
   Baron, JS
   Miller, TL
TI Potential effects of climate chance on surface-water quality in
   North America
SO JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION
AB Data from long-term ecosystem monitoring and research stations
   in North America and results of simulations made with
   interpretive models indicate that changes in climate
   (precipitation and temperature) can have a significant effect
   on the quality of surface waters. Changes in water quality
   during storms, snowmelt, and periods of elevated air
   temperature or drought can cause conditions that exceed
   thresholds of ecosystem tolerance and, thus, lead to water-
   quality degradation. If warming and changes in available
   moisture occur, water-quality changes will likely first occur
   during episodes of climate-induced stress, and in ecosystems
   where the factors controlling water quality are sensitive to
   climate variability. Continued climate stress would increase
   the frequency with which ecosystem thresholds are exceeded and
   thus lead to chronic water-quality changes. Management
   strategies in a warmer climate will therefore be needed that
   are based on local ecological thresholds rather than annual
   median condition. Changes in land use alter biological,
   physical, and chemical processes in watersheds and thus
   significantly alter the quality of adjacent surface waters;
   these direct human-caused changes complicate the interpretation
   of water-quality changes resulting from changes in climate, and
   can be both mitigated and exacerbated by climate change. A
   rigorous strategy for integrated, long-term monitoring of the
   ecological and human factors that control water quality is
   necessary to differentiate between actual and perceived climate
   effects, and to track the effectiveness of our environmental
   policies.
BP 347
EP 366
PG 20
JI J. Am. Water Resour. Assoc.
PY 2000
PD APR
VL 36
IS 2
GA 315LJ
J9 J AM WATER RESOUR ASSOC
UT ISI:000087115000010
ER

PT Journal
AU Chapin, FS
   Zavaleta, ES
   Eviner, VT
   Naylor, RL
   Vitousek, PM
   Reynolds, HL
   Hooper, DU
   Lavorel, S
   Sala, OE
   Hobbie, SE
   Mack, MC
   Diaz, S
TI Consequences of changing biodiversity
SO NATURE
AB Human alteration of the global environment has triggered the
   sixth major extinction event in the history of life and caused
   widespread changes in the global distribution of organisms.
   These changes in biodiversity alter ecosystem processes and
   change the resilience of ecosystems to environmental change.
   This has profound consequences for services that humans derive
   from ecosystems. The large ecological and societal consequences
   of changing biodiversity should be minimized to preserve
   options for future solutions to global environmental problems.
BP 234
EP 242
PG 9
JI Nature
PY 2000
PD MAY 11
VL 405
IS 6783
GA 314WG
J9 NATURE
UT ISI:000087080100061
ER

PT Journal
AU Lundqvist, J
TI A global perspective on water and the environment
SO PHYSICS AND CHEMISTRY OF THE EARTH PART B-HYDROLOGY OCEANS AND
   ATMOSPHERE
AB At the turn to a new millennium, it is titillating to try to
   foresee what issues that are likely to be significant when we
   enter into the next century. Many of the water issues that we
   have been pre-occupied with in the past will, no doubt,
   continue to be important. But in addition, we should be
   prepared for new dimensions in what is now called the
   'impending water crisis'. A pro-active behaviour that would
   make it possible to avoid a new generation of problems is
   warranted as a complement to the need to re-act to and take
   care of old problems. As will be argued below, connections
   between water quantity and quality and between water and the
   environment have been overlooked in the past. (C) 2000 Elsevier
   Science Ltd. All rights reserved.
BP 259
EP 264
PG 6
JI Phys. Chem. Earth Pt B-Hydrol. Oceans Atmos.
PY 2000
VL 25
IS 3
GA 305KT
J9 PHYS CHEM EARTH P B-HYDROL OC
UT ISI:000086539500012
ER

PT Journal
AU Myers, N
TI The new millennium: An ecology and an economy of hope
SO CURRENT SCIENCE
BP 686
EP 693
PG 8
JI Curr. Sci.
PY 2000
PD MAR 25
VL 78
IS 6
GA 300NQ
J9 CURR SCI
UT ISI:000086259400018
ER

PT Journal
AU Ormerod, SJ
   Watkinson, AR
TI The age of applied ecology
SO JOURNAL OF APPLIED ECOLOGY
BP 1
EP 2
PG 2
JI J. Appl. Ecol.
PY 2000
PD FEB
VL 37
IS 1
GA 299JD
J9 J APPL ECOL
UT ISI:000086194600001
ER

PT Journal
AU Lundqvist, J
   Falkenmark, M
TI Drainage basin morphology: a starting point for balancing water
   needs, land use and fishery protection
SO FISHERIES MANAGEMENT AND ECOLOGY
AB The drainage basin, including the coastal zone, may be seen as
   a large-scale system of interlinked natural resources and
   ecosystem services which support human activities on land and
   in the sea. Social and economic activities in the drainage
   basin have to be consistent with the hydrological and
   ecological needs for human well-being. Proper attention must
   also be paid to the impacts of these factors on ecosystems
   further downstream. A macro-scale ecosystem approach to a basin
   has to consider: (1) direct uses of water both instream and
   after extraction when pollutants may be added to the return
   flow; and (2) indirect use of water for agriculture and
   forestry where the river may be depleted as a result of
   evapotranspiration from land surface, crops and trees. Both
   uses have repercussions on the quantitative flow and quality of
   water, which may damage water-based instream ecosystem
   services. The present paper addresses relationships between
   different types of human intervention in a drainage basin and
   their consequences. Two analytical models are introduced: (1) a
   conceptual model which distinguishes between urban and rural
   water uses, and their respective tools; and (2) a conceptual
   model for handling spatially ordered land/water use segments
   subject to different types of interference. Finally, the
   present paper comments on the need to develop methodologies for
   cross-disciplinary dialogue, and for balancing water needs,
   land use and fishery protection.
BP 1
EP 14
PG 14
JI Fisheries Manag. Ecol.
PY 2000
PD FEB
VL 7
IS 1-2
GA 298BE
J9 FISHERIES MANAG ECOL
UT ISI:000086118800002
ER

PT Journal
AU Lemly, AD
   Kingsford, RT
   Thompson, JR
TI Irrigated agriculture and wildlife conservation: Conflict on a
   global scale
SO ENVIRONMENTAL MANAGEMENT
AB The demand for water to support irrigated agriculture has led
   to the demise of wetlands and their associated wildlife for
   decades. This thirst for water is so pervasive that many
   wetlands considered to be hemispheric reserves for waterbirds
   have been heavily affected; for example, the California and
   Nevada wetlands in North America, the Macquarie Marshes in
   Australia, and the Aral Sea in central Asia. These and other
   major wetlands have lost most of their historic supplies of
   water and some have also experienced serious impacts from
   contaminated subsurface irrigation drainage. Now mere shadows
   of what they once were in terms of biodiversity and wildlife
   production, many of the so-called "wetlands of international
   importance" are no longer the key conservation strongholds they
   were in the past. The conflict between irrigated agriculture
   and wildlife conservation has reached a critical point on a
   global scale. Not only has local wildlife suffered, including
   the extinction of highly insular species, but a ripple effect
   has impacted migratory birds worldwide. Human societies reliant
   on wetlands for their livelihoods are also bearing the cost.
   Ironically, most of the degradation of these key wetlands
   occurred during a period of time when public environmental
   awareness and scientific assertion of the need for wildlife
   conservation was at an all-time high. However, designation of
   certain wetlands as "reserves for wildlife" by international
   review boards has not slowed their continued degradation. To
   reverse this trend, land and water managers and policy makers
   must assess the true economic costs of wetland loss and,
   depending on the outcome of the assessment. use the information
   as a basis for establishing legally enforceable water rights
   that protect wetlands from agricultural development.
BP 485
EP 512
PG 28
JI Environ. Manage.
PY 2000
PD MAY
VL 25
IS 5
GA 298AW
J9 ENVIRON MANAGE
UT ISI:000086118000003
ER

PT Journal
AU Sala, OE
   Chapin, FS
   Armesto, JJ
   Berlow, E
   Bloomfield, J
   Dirzo, R
   Huber-Sanwald, E
   Huenneke, LF
   Jackson, RB
   Kinzig, A
   Leemans, R
   Lodge, DM
   Mooney, HA
   Oesterheld, M
   Poff, NL
   Sykes, MT
   Walker, BH
   Walker, M
   Wall, DH
TI Biodiversity - Global biodiversity scenarios for the year 2100
SO SCIENCE
AB Scenarios of changes in biodiversity for the year 2100 can now
   be developed based on scenarios of changes in atmospheric
   carbon dioxide, climate, vegetation, and Land use and the known
   sensitivity of biodiversity to these changes. This study
   identified a ranking of the importance of drivers of change, a
   ranking of the biomes with respect to expected changes, and the
   major sources of uncertainties. For terrestrial ecosystems,
   land-use change probably wilt have the largest effect, followed
   by climate change, nitrogen deposition, biotic exchange, and
   elevated carbon dioxide concentration. For freshwater
   ecosystems, biotic exchange is much more important.
   Mediterranean climate and grassland ecosystems likely will
   experience the greatest proportional change in biodiversity
   because of the substantial influence of all drivers of
   biodiversity change. Northern temperate ecosystems are
   estimated to experience the least biodiversity change because
   major land-use change has already occurred. Plausible changes
   in biodiversity in other biomes depend on interactions among
   the causes of biodiversity change. These interactions represent
   one of the largest uncertainties in projections of future
   biodiversity change.
BP 1770
EP 1774
PG 5
JI Science
PY 2000
PD MAR 10
VL 287
IS 5459
GA 292BY
J9 SCIENCE
UT ISI:000085775300030
ER

PT Journal
AU Tilman, D
TI The ecological consequences of changes in biodiversity: A
   search for general principles
SO ECOLOGY
AB This paper uses theory and experiments to explore the effects
   of diversity on stability, productivity, and susceptibility to
   invasion. A model of resource competition predicts that
   increases in diversity cause community stability to increase,
   but population stability to decrease. These opposite effects
   are, to a great extent, explained by how temporal variances in
   species abundances scale with mean abundance, and by the
   differential impact of this scaling on population vs. community
   stability. Community stability also depends on a negative
   covariance effect (competitive compensation) and on
   overyielding (ecosystem productivity increasing with
   diversity). A long-term study in Minnesota grasslands supports
   these predictions. Models of competition predict, and field
   experiments confirm, that greater plant diversity leads to
   greater primary productivity. This diversity-productivity
   relationship results both from the greater chance that a more
   productive speicies would be present at higher diversity (the
   sampling effect) and from the better "coverage" of habitat
   heterogeneity caused by the broader range of species traits in
   a more diverse community (the niche differentiation effect).
   Both effects cause more complete utilization of limiting
   resources at higher diversity, which increases resource
   retention, further increasing productivity. Finally, lower
   levels of available limiting resources at higher diversity are
   predicted to decrease the susceptibility of an ecosystem to
   invasion, supporting the diversity-invasibility hypothesis.
   This mechanism provides rules for community assembly and
   invasion resistance. In total, biodiversity should be added to
   species composition, disturbance, nutrient supply, and climate
   as a major controller of population and ecosystem dynamics and
   structure. By their increasingly great directional impacts on
   all of these controllers, humans are likely to cause major
   long-term changes in the functioning of ecosystems worldwide. A
   better understanding of these ecosystem changes is needed if
   ecologists are to provide society with the knowledge essential
   for wise management of the earth and its biological resources.
BP 1455
EP 1474
PG 20
JI Ecology
PY 1999
PD JUL
VL 80
IS 5
GA 281XZ
J9 ECOLOGY
UT ISI:000085187900001
ER

PT Journal
AU Jansson, R
   Nilsson, C
   Dynesius, M
   Andersson, E
TI Effects of river regulation on river-margin vegetation: A
   comparison of eight boreal rivers
SO ECOLOGICAL APPLICATIONS
AB Regulation and fragmentation by dams belong to the most
   widespread deliberate impacts of humans on the world's rivers,
   especially in the Northern Hemisphere. We evaluated the effects
   of hydroelectric development by comparing the flora of vascular
   plants in 200-m-long reaches of river margin distributed along
   eight entire rivers in northern Sweden. Four of these rivers
   were free-flowing, and four were strongly regulated for
   hydroelectric purposes. First, we compared species diversity
   per site between entire free-flowing and regulated rivers. To
   reduce the effects of natural, between-river variation, we
   compared adjacent rivers. One regulated river had lower plant
   species richness and cover than two adjacent free-flowing ones,
   whereas two other parallel rivers, one regulated and another
   free-flowing, did not differ significantly. Second, river-
   margin vegetation responded differently to different types of
   regulated water-level regimes. Both along run-of-river
   impoundments, with small but daily water-level fluctuations,
   and along storage reservoirs, with large fluctuations between
   low water levels in spring and high levels in late summer and
   fall, the number of species and their cover per site were lower
   than along the free-flowing rivers. Regulated but unimpounded
   reaches were most similar to free-flowing rivers, having lower
   plant cover per site, but similar numbers of species. For
   reaches with reduced discharge, evidence was mixed; some
   variables were lower compared to free-flowing rivers whereas
   others were not. However, for the last two types of regulation,
   statistical power was low due to small sample sizes. Third, we
   classified all plant species according to their dispersal
   mechanisms and tested whether they respond differently to
   different types of regulated water-level regimes. Three out of
   four types of regulation had higher proportions of wind-
   dispersed species, and two out of four had lower proportions of
   species without specific mechanisms for dispersal, compared to
   free-flowing rivers, suggesting that dispersal ability is
   critical for persistence following regulation. Run-of-river
   impoundments had higher proportions of long-floating species
   and species with mechanisms for vegetative dispersal,
   suggesting that water dispersal may still be important despite
   fragmentation by dams. Fourth, plant species richness and cover
   varied with both local factors, such as water-level regime, and
   regional factors, such as length of the growing season.
   Presence of clay and silt in the river-margin soil,
   preregulation position of the contemporary river margin, non-
   reservoir sites, low altitudes, and long growing seasons were
   associated with high plant species richness and cover.
BP 203
EP 224
PG 22
JI Ecol. Appl.
PY 2000
PD FEB
VL 10
IS 1
GA 280NG
J9 ECOL APPL
UT ISI:000085108400016
ER

PT Journal
AU Ramankutty, N
   Foley, JA
TI Estimating historical changes in land cover: North American
   croplands from 1850 to 1992
SO GLOBAL ECOLOGY AND BIOGEOGRAPHY
AB 1. We present a simple algorithm for reconstructing spatially
   explicit historical changes in croplands. We initialize our
   simulation with a satellite-derived characterization of
   present-day croplands c. 1992. This data set of croplands is
   then used within a simple model, along with historical cropland
   inventory data at the national and subnational level, to
   reconstruct historical crop cover. We present an annual data
   set of cropland areas in North America between 1850 and 1992,
   at a spatial resolution of 5 min (approximate to 10 km). 2. The
   reconstructed changes in North American crop cover are
   generally consistent with qualitative descriptions of change.
   Crop cover is initially concentrated in the eastern portions of
   the continent, and subsequently migrates westward into the
   Midwestern United States and the Prairie Provinces of Canada.
   We also see cropland abandonment in the eastern portions of the
   continent during the 20th century. The simulation, however,
   fails to characterize adequately the changes in crop cover in
   Mexico. 3. We also estimate the extent to which the different
   vegetation types of North America have been cleared for
   cultivation. We find that savannas/grasslands/steppes and
   forests/woodlands have undergone the most extensive conversion
   (1.68 and 1.40 million km(2) cleared, respectively, since
   1850). We further discuss the wider implications of such large-
   scale changes in land cover.
BP 381
EP 396
PG 16
JI Glob. Ecol. Biogeogr.
PY 1999
PD SEP
VL 8
IS 5
GA 279NM
J9 GLOBAL ECOL BIOGEOGR
UT ISI:000085051400007
ER

PT Journal
AU Meyer, JL
   Sale, MJ
   Mulholland, PJ
   Poff, NL
TI Impacts of climate change on aquatic ecosystem functioning and
   health
SO JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION
AB We review published analyses of the effects of climate change
   on goods and services provided by freshwater ecosystems in the
   United States. Climate-induced changes must be assessed in the
   context of massive anthropogenic changes in water quantity and
   quality resulting from altered patterns of land use, water
   withdrawal, and species invasions; these may dwarf or
   exacerbate climate-induced changes. Water to meet instream
   needs is competing with other uses of water, and that
   competition is likely to be increased by climate change. We
   review recent predictions of the impacts of climate change on
   aquatic ecosystems in eight regions of North America. Impacts
   include warmer temperatures that alter lake mixing regimes and
   availability of fish habitat; changed magnitude and seasonality
   of runoff regimes that alter nutrient loading and limit habitat
   availability at low flow; and loss of prairie pothole wetlands
   that reduces waterfowl populations. Many of the predicted
   changes in aquatic ecosystems are a consequence of climatic
   effects on terrestrial ecosystems; shifts in riparian
   vegetation and hydrology are particularly critical. We review
   models that could be used to explore potential effects of
   climate change on freshwater ecosystems; these include models
   of instream flow, bioenergetics models, nutrient spiraling
   models, and models relating riverine food webs to hydrologic
   regime. We discuss potential ecological risks, benefits, and
   costs of climate change and identify information needs and
   model improvements that are required to improve our ability to
   predict and identify climate change impacts and to evaluate
   management options.
BP 1373
EP 1386
PG 14
JI J. Am. Water Resour. Assoc.
PY 1999
PD DEC
VL 35
IS 6
GA 271ZB
J9 J AM WATER RESOUR ASSOC
UT ISI:000084624600008
ER

PT Journal
AU Ramankutty, N
   Foley, JA
TI Estimating historical changes in global land cover: Croplands
   from 1700 to 1992
SO GLOBAL BIOGEOCHEMICAL CYCLES
AB Human activities over the last three centuries have
   significantly transformed the Earth's environment, primarily
   through the conversion of natural ecosystems to agriculture.
   This study presents a simple approach to derive geographically
   explicit changes in global croplands from 1700 to 1992. By
   calibrating a remotely sensed land cover classification data
   set against cropland inventory data, we derived a global
   representation of permanent croplands in 1992, at 5 min spatial
   resolution [Ramankutty and Foley, 1998]. To reconstruct
   historical croplands, we first compile an extensive database of
   historical cropland inventory data, at the national and
   subnational level, from a variety of sources. Then we use our
   1992 cropland data within a simple land cover change model,
   along with the historical inventory data, to reconstruct global
   5 min resolution data on permanent cropland areas from 1992
   back to 1700. The reconstructed changes in historical croplands
   are consistent with the history of human settlement and
   patterns of economic development. By overlaying our historical
   cropland data set over a newly derived potential vegetation
   data set, we analyze our results in terms of the extent to
   which different natural vegetation types have been converted
   for agriculture. We further examine the extent to which
   croplands have been abandoned in different parts of the world.
   Our data sets could be used within global climate models and
   global ecosystem models to understand the impacts of land cover
   change on climate and on the cycling of carbon and water. Such
   an analysis is a crucial aid to sharpen our thinking about a
   sustainable future.
BP 997
EP 1027
PG 31
JI Glob. Biogeochem. Cycle
PY 1999
PD DEC
VL 13
IS 4
GA 270VK
J9 GLOBAL BIOGEOCHEM CYCLE
UT ISI:000084557700013
ER

PT Journal
AU Ormerod, SJ
TI Three challenges for the science of river conservation
SO AQUATIC CONSERVATION-MARINE AND FRESHWATER ECOSYSTEMS
BP 551
EP 558
PG 8
JI Aquat. Conserv.-Mar. Freshw. Ecosyst.
PY 1999
PD NOV-DEC
VL 9
IS 6
GA 271LC
J9 AQUAT CONSERV
UT ISI:000084594200011
ER

PT Journal
AU Pringle, CM
TI Changing academic culture: interdisciplinary, science-based
   graduate programmes to meet environmental challenges in
   freshwater ecosystems
SO AQUATIC CONSERVATION-MARINE AND FRESHWATER ECOSYSTEMS
AB Listening in on the easy private banter of scientists, one
   hears deprecation of the politicians who run this world and
   wishful claims for the rationality of science. If only the
   scientific approach were applied to the way countries are
   governed, it is supposed, the world's problems would vanish....
   Confused, even hurt, by the complexity of the world they live
   in, scientists reach naively for the dream that the wild
   universe of emotions and collective actions is governed by some
   rational principles, still to be discovered (Hoffman, 1990).
BP 615
EP 620
PG 6
JI Aquat. Conserv.-Mar. Freshw. Ecosyst.
PY 1999
PD NOV-DEC
VL 9
IS 6
GA 271LC
J9 AQUAT CONSERV
UT ISI:000084594200020
ER

PT Journal
AU Princen, T
TI Consumption and environment: some conceptual issues
SO ECOLOGICAL ECONOMICS
AB Consumption ranks with population and technology as a major
   driver of environmental change and yet researchers and
   policymakers have paid it scant attention. When the topic is
   addressed, its conceptual foundations are either taken as self-
   evident or are conflated with production, overall economic
   activity, materialism, maldistribution, population or
   technology. The risk is to adopt the latest buzzword in the
   environmental debate, stretch the concept to encompass all
   conceivable concerns, and forfeit any advantage-for analysis or
   for behavior change-that may accrue to a new perspective on
   environmental problems. Consumption must be distinguished
   conceptually from other approaches to environmental problems.
   One approach is to work within the consumption-production
   dichotomy, examining not just purchasing but product use and
   non-purchase decisions. A second approach, one that challenges
   the prevailing dichotomy and its propensity to relegate
   consumption to a black box, is to treat all resource use as
   consuming, that is, 'using up', and ask what risks are
   entailed. Consumption can then be seen as material provisioning
   where risks increase with increasing distance from the
   resource; as background, misconsumption, or overconsumption
   depending on the social concern raised; or as a chain of
   decisions that compel the behaviors of restraint and resistance
   among 'producers'. Pursuing the consumption and environment
   topic engenders resistance among a wide range of actors for
   reasons that are personal, analytic, and policy related.
   Nevertheless, the topic appears to have the potential of
   helping analysts and others transcend conventional approaches
   to excess throughput. (C) 1999 Elsevier Science B.V. All rights
   reserved.
BP 347
EP 363
PG 17
JI Ecol. Econ.
PY 1999
PD DEC
VL 31
IS 3
GA 265MD
J9 ECOL ECON
UT ISI:000084247200006
ER

PT Journal
AU Havens, KE
   Aumen, NG
TI Hypothesis-driven experimental research is necessary for
   natural resource management
SO ENVIRONMENTAL MANAGEMENT
AB Effective management of natural resources must be grounded in a
   solid scientific understanding of the ecosystem and its
   responses to natural and human-induced stress. Such an
   understanding does not arise easily from observational data and
   models that are not substantiated by experimental data. Cause-
   and-effect relationships are more easily documented when
   observations and/or models are supplemented by hypothesis-
   driven experimental research. In this paper we present three
   examples from south Florida where hypothesis-driven
   experimental research has been combined with observational data
   collection to address specific resource management questions.
   These include research to determine: (I)the cause of cattail
   expansion in the Everglades; (2) a threshold phosphorus
   concentration for the Everglades; and (3) optimal salinity
   criteria for Florida estuaries. In each case, the results have
   led to a better understanding of ecosystem function and more
   sound guidance for resource managers than was possible without
   the hypothesis-drive experimental research. Resource managers
   need to recognize the merits of this holistic approach to
   environmental science and management if we are to have success
   in reversing detrimental human impacts on natural ecosystems.
BP 1
EP 7
PG 7
JI Environ. Manage.
PY 2000
PD JAN
VL 25
IS 1
GA 260VW
J9 ENVIRON MANAGE
UT ISI:000083975000001
ER

PT Journal
AU Redford, KH
   Richter, BD
TI Conservation of biodiversity in a world of use
SO CONSERVATION BIOLOGY
AB Biodiversity conservation has become the stated objective of
   national governments, state agencies, local communities, and
   scientific organizations Yet despite this attention tbe term
   biodiversity remains poorly defined. One of the unfortunate
   consequences of this lack of definition is a proliferation of
   claims that biodiversity can De both used and conserved. This
   claim is difficult to assess without a more precise way of
   defining biodiversity. We offer a heuristic framework for
   measuring the consequences of human use for biodiversity. Our
   definition of biodiversity includes three components: genetic,
   population/species, and community/ecosystem. Each component has
   its own three attributes: composition, structure, and function.
   Using this definition, we assessed the effects of different
   types of human use on the different components and attributes
   of biodiversity. We shore that (I) different degrees of human
   use or alteration result in differential conservation of
   biodiversity components; (2) some components non attributes of
   biodiversity are more sensitive to human use than others; and
   (3) only extremely limited use or virtually no alteration will
   protect ail components.
BP 1246
EP 1256
PG 11
JI Conserv. Biol.
PY 1999
PD DEC
VL 13
IS 6
GA 260RF
J9 CONSERV BIOL
UT ISI:000083963100006
ER

PT Journal
AU Ayensu, E
   Claasen, DV
   Collins, M
   Dearing, A
   Fresco, L
   Gadgil, M
   Gitay, H
   Glaser, G
   Lohn, CL
   Krebs, J
   Lenton, R
   Lubchenco, L
   McNeely, JA
   Mooney, HA
   Pinstrup-Andersen, P
   Ramos, M
   Raven, P
   Reid, WV
   Samper, C
   Sarukhan, J
   Schei, P
   Tundisi, JG
   Watson, RT
   Xu, GH
   Zakri, AH
TI Ecology - International ecosystem assessment
SO SCIENCE
BP 685
EP 686
PG 2
JI Science
PY 1999
PD OCT 22
VL 286
IS 5440
GA 248XZ
J9 SCIENCE
UT ISI:000083303200030
ER

PT Journal
AU Ehrlich, PR
   Wolff, G
   Daily, GC
   Hughes, JB
   Daily, S
   Dalton, M
   Goulder, L
TI Knowledge and the environment
SO ECOLOGICAL ECONOMICS
AB Some recent analyses suggest that future increases in knowledge
   will, more or less automatically, alleviate or even eliminate
   future environmental problems. Here we examine this issue.
   First, we discuss whether a knowledge explosion is indeed
   occurring, addressing some of the problems with assessing
   knowledge-growth We next consider whether growth in knowledge
   will help the environment; we ask whether future advances in
   knowledge are likely to assure benign environmental outcomes,
   and discuss physical limitations of reducing resource
   consumption. Finally, we outline policy interventions that
   would help produce and implement environmentally helpful
   knowledge. Although knowledge-growth can help attenuate future
   environmental problems, we are skeptical as to the ability of
   advances in knowledge to offset fully the adverse environmental
   impacts of continued growth of population and per-capita
   consumption. The ongoing shift from a material-based to a
   services-based economy reduces, but does not eliminate, the
   significant environmental impacts associated with the
   increasing scale of economic output. in addition, the ability
   of the economy to replace certain key natural resource inputs
   with knowledge inputs must eventually encounter limits. Public
   policy has a crucial role both in discouraging environmentally
   damaging forms of consumption, and in promoting the generation
   and diffusion of environmentally beneficial knowledge. (C) 1999
   Elsevier Science B.V. All rights reserved.
BP 267
EP 284
PG 18
JI Ecol. Econ.
PY 1999
PD AUG
VL 30
IS 2
GA 238WJ
J9 ECOL ECON
UT ISI:000082737300007
ER

PT Journal
AU Rockstrom, J
TI On-farm green water estimates as a tool for increased food
   production in water scarce regions
SO PHYSICS AND CHEMISTRY OF THE EARTH PART B-HYDROLOGY OCEANS AND
   ATMOSPHERE
AB Rainfed agriculture covers > 95 % of the crop lands in water
   scarce tropical regions, and will in a forseeable future be the
   dominating source of food for growing populations in the
   tropics. Despite this fact, focus has until recently been on
   water used for irrigated agriculture, industry and households -
   the so called "blue" water recharging rivers, lakes and
   aquifers. Yield levels have to increase substantially in order
   to guarantee a minimum of livelihood security in dry tropical
   regions. This paper focuses on the potential of improving the
   efficient use of rainfall through integrated soil nutrient and
   water management. Results are presented from an on-farm water
   balance research project on pearl miller in the Sahel (Niger).
   The findings indicate that only a very small fraction of the
   rainfall, 4 - 9 %, takes the productive water flow path as
   "green" transpiration water. Surface runoff was substantial,
   amounting to 25 - 50 % of rainfall for intensive events,
   despite sandy soils. Soil evaporation amounted to around 50 %
   of annual rainfall. Drainage was significant in this dryland
   farming system, despite the presence of periods of severe water
   scarcity during critical growth phases. Very low water use
   efficiencies were observed, with a range of 4000 - 8000 m(3) of
   evapotranspiration water needed to produce 1 ton of grain
   yield, indicating a large potential for increased yield and
   productive "green" water flow. An option discussed is water
   harvesting techniques for supplementary irrigation. (C) 1999
   Elsevier Science Ltd. All rights reserved.
BP 375
EP 383
PG 9
JI Phys. Chem. Earth Pt B-Hydrol. Oceans Atmos.
PY 1999
VL 24
IS 4
GA 234NV
J9 PHYS CHEM EARTH P B-HYDROL OC
UT ISI:000082491500015
ER

PT Journal
AU Jansson, A
   Folke, C
   Rockstrom, J
   Gordon, L
TI Linking freshwater flows and ecosystem services appropriated by
   people: The case of the Baltic Sea drainage basin
SO ECOSYSTEMS
AB Humanity's dependence on ecosystem support is "mentally hidden"
   to large segments of society; it has no price in the market and
   is seldom accounted for in decision making. Similarly the needs
   of ecosystems for fresh water for generation of nature's
   services are largely invisible. Freshwater assessments
   predominantly have focused on human uses of liquid water in
   rivers, lakes, and reservoirs. We estimated the spatial
   appropriation of terrestrial and marine ecosystems-the
   ecological footprint-of the 85 million inhabitants in the
   Baltic Sea drainage basin with regard to consumption of food
   and timber and waste assimilation of nutrients and carbon
   dioxide. We also estimated the amount of fresh water-the water
   vapor flow-that the inhabitants depend upon for their
   appropriation of these ecosystem services. The ecological
   footprint estimate corresponds to an area as large as 8.5-9.5
   times the Baltic Sea and its drainage basin with a per capita
   ecosystem appropriation of 220,000-250,000 m(2). This large
   estimate is mainly attributed to carbon sequestering by marine
   ecosystems and forests. The water vapor flow of the ecological
   footprint of forests, wetlands, agriculture, and inland water
   bodies for making the human appropriation of ecosystem services
   possible is estimated at 1175-2875 km(3) y(-1). Human
   dependence on water vapor flows for ecosystem services is as
   great as 54 times the amount of freshwater runoff that is
   assessed and managed in society. Decision making on an
   increasingly human-dominated planet will have to address
   explicitly the critical interdependencies between freshwater
   flows and the capacity of ecosystems to generate services. We
   advocate a dynamic ecohydrological landscape-management
   approach upstream and downstream in watersheds to reduce
   unintentional impacts, irreversible change, and further loss of
   freshwater resources, ecosystem. services, and resilience.
BP 351
EP 366
PG 16
JI Ecosystems
PY 1999
PD JUL-AUG
VL 2
IS 4
GA 227BG
J9 ECOSYSTEMS
UT ISI:000082057600012
ER

PT Journal
AU Turner, P
   Tschirhart, J
TI Green accounting and the welfare gap
SO ECOLOGICAL ECONOMICS
AB Although gross domestic product (GDP) is not intended to be a
   measure of societal welfare, it is often used as such. One
   shortcoming as a welfare measure is that it fails to account
   for the non-marketed value of natural resource flows. The
   difference between societal welfare and GDP is labelled the
   'welfare gap'. A model that accounts for both market and non-
   market income flows from natural capital is used to examine
   this gap. Societal welfare depends on private goods and the
   stock of natural capital. The latter is subject to a logistic
   growth relationship common to many non-human species. Private
   goods are produced using human capital and flows of natural
   capital. An exogenously growing human population either
   harvests the natural resource, produces human capital or
   produces the private good. Optimal control theory and dynamic
   simulations provide steady-state harvest and human capital
   growth rates which determine the steady-state natural resource
   stock, GDP and societal welfare growth rates. The model
   illustrates the feasibility of explicitly accounting for
   ecological relationships in economic growth models and shows
   that, depending on one's preferences and the growth rate of
   human population and the intrinsic growth rate of natural
   resources, GDP may diverge substantially from the growth rate
   of societal welfare, leaving a large welfare gap. (C) 1999
   Elsevier Science B.V. All rights reserved.
BP 161
EP 175
PG 15
JI Ecol. Econ.
PY 1999
PD JUL
VL 30
IS 1
GA 221RN
J9 ECOL ECON
UT ISI:000081740200014
ER

PT Journal
AU Smil, V
TI Nitrogen in crop production: An account of global flows
SO GLOBAL BIOGEOCHEMICAL CYCLES
AB Human activities have roughly doubled the amount of reactive N
   that enters the element's biospheric cycle. Crop production is
   by far the single largest cause of this anthropogenic
   alteration. Inorganic fertilizers now provide 80 Tg N yr(-1)
   (Tg = 10(12) g), managed (symbiotic) biofixation adds about 20
   Tg N yr(-1), and between 28 and 36 Tg N yr(-1) are recycled in
   organic wastes. Anthropogenic inputs (including N in seeds and
   irrigation water) now supply about 85% of 170 (151-186) Tg N
   reaching the world's cropland every year. About half of this
   input, 85 Tg N yr(-1), is taken up by harvested crops and their
   residues. Quantification of N losses from crop fields is beset
   by major uncertainties. Losses to the atmosphere
   (denitrification and volatilization) amount to 26-60 Tg N yr(-
   1),while waters receive (from leaching and erosion) 32-45 Tg N
   yr(-1) These N losses are the major reason behind the growing
   concerns about the enrichment of the biosphere with reactive N.
   The best evidence suggests that in spite of some significant
   local and regional losses, the world's agricultural land
   accumulates N. The addition of 3-4 billion people before the
   year 2050 will require further substantial increases of N input
   in cropping, but a large share of this demand can come from
   improved efficiency of N fertilizer use.
BP 647
EP 662
PG 16
JI Glob. Biogeochem. Cycle
PY 1999
PD JUN
VL 13
IS 2
GA 213GQ
J9 GLOBAL BIOGEOCHEM CYCLE
UT ISI:000081264700023
ER

PT Journal
AU Benstead, JP
   March, JG
   Pringle, CM
   Scatena, FN
TI Effects of a low-head dam and water abstraction on migratory
   tropical stream biota
SO ECOLOGICAL APPLICATIONS
AB Migration of large-bodied "macroconsumers" (e.g., fishes,
   shrimps, and snails) is an important functional linkage between
   many tropical rivers and their estuaries. Increasingly, this
   linkage is being severed by darns and water abstraction. The
   ecological impacts of these activities are poorly understood
   and are largely being ignored by dam operators. We investigated
   the direct effects of a water intake and low-head dam on the
   migration of amphidromous freshwater shrimps between the
   headwater streams and estuary of the Rio Espiritu Santo, Puerto
   Rico, USA. Both downstream migratory drift of larvae and
   upstream migration of postlarvae had strong diel patterns, with
   most activity occurring at night. Unlike large dams on the
   island, this low-head dam did not act as a complete barrier to
   the upstream migration of metamorphosed postlarvae. However,
   the dam did cause large numbers of postlarval shrimps to
   accumulate directly downstream of the structure. Mortality of
   drifting first-stage larvae by entrainment into the water
   intake during downstream migration averaged 42% during the 69-d
   study period. During low discharges, 100% of the drifting
   larvae were entrained by the intake. The rate of nocturnal
   entrainment-induced mortality averaged 233 larvae/s and peaked
   at 1167 larvae/s. We used our held data and a 30-yr discharge
   record to model the long-term impacts of different intake
   management strategies on the entrainment mortality at this dam.
   The simulation model estimated long-term mean daily entrainment
   mortality at 34-62%, depending on the amount of water extracted
   from the river. Monthly differences in mean daily entrainment
   mortality (27-76% depending on estimates of abstraction) were
   caused by seasonal variation in discharge. Modeling of
   mitigation options suggested that daily entrainment mortality
   of larvae could be reduced to 11-20% if water abstraction was
   halted for 5 h during evening periods of peak drift. Impacts of
   the dam and operations can be significantly ameliorated by 3-5
   h stoppages in water abstraction during peak nocturnal larval
   drift, upkeep of a functional fish ladder, and maintenance of
   minimum flow over the dam. Since the impacts of dams depend on
   the hydrology and design of specific water intake systems,
   mitigation strategies must be tailored to individual dams and
   intakes. However, our approach and results are likely to apply
   to low-head dams throughout the range of amphidromous species.
BP 656
EP 668
PG 13
JI Ecol. Appl.
PY 1999
PD MAY
VL 9
IS 2
GA 213AQ
J9 ECOL APPL
UT ISI:000081250200030
ER

PT Journal
AU Yount, JD
TI Biophysical assessments: who cares?
SO ECOLOGICAL ECONOMICS
BP 19
EP 21
PG 3
JI Ecol. Econ.
PY 1999
PD APR
VL 29
IS 1
GA 202BY
J9 ECOL ECON
UT ISI:000080633300007
ER

PT Journal
AU Tilman, D
TI Global environmental impacts of agricultural expansion: The
   need for sustainable and efficient practices
SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED
   STATES OF AMERICA
AB The recent intensification of agriculture, and the prospects of
   future intensification, will have major detrimental impacts on
   the nonagricultural terrestrial and aquatic ecosystems of the
   world. The doubling of agricultural food production during the
   past 35 years was associated with a 6.87-fold increase in
   nitrogen fertilization, a 3.48-fold increase in phosphorus
   fertilization, a 1.68-fold increase in the amount of irrigated
   cropland, and a 1.1-fold increase in land in cultivation. Based
   on a simple linear extension of past trends, the anticipated
   next doubling of global food production would be associated
   with approximately 3-fold increases in nitrogen and phosphorus
   fertilization rates, a doubling of the irrigated land area, and
   an 18% increase in cropland. These projected changes would have
   dramatic impacts an the diversity, composition, and functioning
   of the remaining natural ecosystems of the world, and on their
   ability to provide society with a variety of essential
   ecosystem services. The largest impacts would be on freshwater
   and marine ecosystems, which would be greatly eutrophied by
   high rates of nitrogen and phospho rus release from
   agricultural fields. Aquatic nutrient eutrophication can lead
   to loss of biodiversity, outbreaks of nuisance species, shifts
   in the structure of food chains, and impairment of fisheries.
   Because of aerial redistribution of various forms of nitrogen,
   agricultural intensification also would eutrophy many natural
   terrestrial ecosystems and contribute to atmospheric
   accumulation of greenhouse gases. These detrimental
   environmental impacts of agriculture tan be minimized only if
   there is much more efficient use and recycling of nitrogen and
   phosphorus in agroecosystems.
BP 5995
EP 6000
PG 6
JI Proc. Natl. Acad. Sci. U. S. A.
PY 1999
PD MAY 25
VL 96
IS 11
GA 200ER
J9 PROC NAT ACAD SCI USA
UT ISI:000080527100019
ER

PT Journal
AU Kingsford, RT
TI Aerial survey of waterbirds on wetlands as a measure of river
   and floodplain health
SO FRESHWATER BIOLOGY
AB 1. This study highlights the use of waterbird communities as
   potential measures of river and floodplain health at a
   landscape scale. 2. The abundance and diversity of a waterbird
   community (54 species) was measured over 15 trips with four
   aerial and three ground counts per trip on a 300-ha lake in
   arid Australia. 3. Aerial survey estimates of individual
   species were significantly less precise (SE/mean) than ground
   counts across two (11-100 and > 1000) out of lour abundance
   classes of waterbirds: 0-10, 11-100, 101-1800 and > 1000.
   Standard error/mean as a percentage decreased with increasing
   abundance from about 60% for the lowest abundance class to 18%
   for the largest abundance class. 4. Aerial survey estimates
   were negatively biased for species in numbers of less than 10
   and greater than 5000 but unbiased compared to ground counts
   for other abundance classes. Aerial surveys underestimated
   numbers of waterbirds by 50% when there were 40000 waterbirds.
   Three ground counts found about seven more waterbird species
   than four aerial surveys. One ground count took about 150 times
   longer than two aerial surveys and cost 14 times more. 5.
   Regression models were derived, comparing aerial survey
   estimates to ground counts for 31 of 36 species for which there
   were sufficient data. Aerial survey estimates were unbiased for
   most of these species (67%), negatively biased for six species
   and positively biased for one species. Estimates were
   negatively biased in species that occurred in small numbers or
   that dived in response to the aircraft. 6. River system health
   encompasses the state of floodplain wetlands. Waterbirds on an
   entire wetland or floodplain may be estimated by aerial survey
   of waterbirds; this is a coarse but effective measure of
   waterbird abundance. Aerial survey is considerably less costly
   than ground survey and potentially provides a method for
   measuring river and floodplain health over long periods of time
   at the same scale as river management.
BP 425
EP 438
PG 14
JI Freshw. Biol.
PY 1999
PD MAR
VL 41
IS 2
GA 194HT
J9 FRESHWATER BIOL
UT ISI:000080187100016
ER

PT Journal
AU Myers, N
TI The next green revolution: Its environmental underpinnings
SO CURRENT SCIENCE
BP 507
EP 513
PG 7
JI Curr. Sci.
PY 1999
PD FEB 25
VL 76
IS 4
GA 177BD
J9 CURR SCI
UT ISI:000079186800016
ER

PT Journal
AU Kingsford, RT
   Johnson, W
TI Impact of water diversions on colonially-nesting waterbirds in
   the Macquarie Marshes of arid Australia
SO COLONIAL WATERBIRDS
AB The building of dams and subsequent diversion of water from the
   Macquarie River have had a significant impact on the breeding
   of colonial waterbuds in the Macquarie Marshes, New South
   Wales, southeastern Australia. Annual flows (1978, 1986-1996),
   measured at Oxley where the Marshes begin, were significantly
   related to total colony sire (number of nests) and sizes of sis
   nesting Ciconiidae (Intermediate Egret Ardea intermedia, Rufous
   Night Heron Nycticorax caledonicus, Glossy Ibis Plegadis
   falcinellus, Straw-necked Ibis Threskiornis spinicollis,
   Australian White Ibis Threskiornis mollucca and. Royal
   Spoonbill Platalea regia) colonies. We used these results and
   available historical flow; data extending back to 1944 to
   demonstrate the probable impact of water diversions on breeding
   in these colonial nesting species. The impact of Burrendong
   Dam, opened in 1967, and Windamere Dam, opened in 1984, on the
   numbers of nests would have been significant. instead of a
   colony of more than 100,000 nests in 1969, a colony of less
   than 10,000 probably established. Similarly, in 1984, a colony
   of more than 100,000 could have been established with no water
   diversions, but in all likelihood the colony was less than
   5,000. Generally colony sizes were significantly less (100,000
   over 11 years) than would be expected without diversions of
   water upstream. Colony sizes of more than 100,000 nests
   estimated during the floods of the 1950s are unlikely to occur
   again. Numbers of annual breeding events also declined with
   water diversions from ten to seven (1963-1973); eight to seven
   (1974-1984) and eight to five (1985-1995).
BP 159
EP 170
PG 12
JI Colon. Waterbirds
PY 1998
VL 21
IS 2
GA 158XY
J9 COLON WATERBIRD
UT ISI:000078143800005
ER

PT Journal
AU Kirpich, PZ
   Haman, DZ
   Styles, SW
TI Problems of irrigation in developing countries
SO JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING-ASCE
AB This paper describes the crucial importance of irrigated
   agriculture to developing countries and to the world as a
   whole. This is followed by a summary of key problems that
   restrict and diminish the benefits of irrigated agriculture.
   Solution of these problems will above all require a holistic
   approach and will require changes in the institutions involved.
   These institutions include those of the developing countries,
   of the developed countries that provide aid, and of the
   international financing and technical-assistance agencies.
   Engineers in the developed countries have had, and will
   continue to have, a leading role but will need some
   redirection. ASCE could provide valuable assistance in this
   redirection.
BP 1
EP 6
PG 6
JI J. Irrig. Drainage Eng-ASCE
PY 1999
PD JAN-FEB
VL 125
IS 1
GA 157WH
J9 J IRRIG DRAIN ENG-ASCE
UT ISI:000078084300001
ER

PT Journal
AU Ramankutty, N
   Foley, JA
TI Characterizing patterns of global land use: An analysis of
   global croplands data
SO GLOBAL BIOGEOCHEMICAL CYCLES
AB Human activities have shaped significantly the state of
   terrestrial ecosystems throughout the world. One of the most
   direct manifestations of human activity within the biosphere
   has been the conversion of natural ecosystems to croplands. In
   this study, we present an analysis of the geographic
   distribution and spatial extent of permanent croplands. This
   analysis represents the area in permanent croplands during the
   early 1990s for each grid cell on a global 5 min (similar to 10
   km) resolution latitude-longitude grid. To create this data
   set, we have combined a satellite-derived land cover data set
   with a variety of national and subnational agricultural
   inventory data. A simple calibration algorithm was used so that
   the spatial land cover data were generally consistent with
   nonspatial agricultural inventory data. The spatial
   distribution of croplands represented in this analysis presents
   a quantitative depiction of global agricultural geography. The
   regions of the world known to have intense cultivation (e.g.,
   the North American corn belt, the European wheat-corn belt, the
   Ganges floodplain, and eastern China) are clearly portrayed in
   this analysis. It also captures the less intensely cultivated
   regions of the world, usually surrounding the regions mentioned
   above, and regions characterized by subsistence agriculture
   (e.g., Sahelian Africa). Data generated from this kind of
   analysis can be used within global climate models and global
   ecosystem models to assess the importance of permanent
   croplands on environmental processes. In particular, these
   data, combined with models, could help evaluate the role of
   changing land cover on regional climate and carbon cycling.
   Future efforts will need to concentrate on other land use
   systems, including pastures and regions of shifting
   cultivation. Furthermore, land use and land cover data must be
   extended to include an historical dimension so as to evaluate
   the changing state of the biosphere over time.
BP 667
EP 685
PG 19
JI Glob. Biogeochem. Cycle
PY 1998
PD DEC
VL 12
IS 4
GA 148BZ
J9 GLOBAL BIOGEOCHEM CYCLE
UT ISI:000077533900010
ER

PT Journal
AU Lundqvist, J
TI Avert looming hydrocide
SO AMBIO
AB Water is increasingly high on international and national
   agendas. Recent assessments show that the conventional focus on
   supply of water to users, without attention to how water is
   used or wastewater disposed, has led to serious degradation of
   water and environmental quality. "Hydrocide" is impending; the
   life-giving qualities of water are obstructed. Impairment to
   human health, destabilization of ecosystems, and repercussions
   on the economy are widely experienced. The challenge to avert
   hydrocide is significant. Investments required to deal with
   water-quality degradation are, on average, ten times higher, or
   more, compared to expenditures on structures for water supply.
   Financial requirements, and a tendency to see water services as
   free, and without reciprocal responsibility for the users, lead
   to heavy pressures on public budgets and policy makers. To
   avert hydrocide, a water ethic needs to be introduced together
   with incentives and sanctions for proper and responsible use of
   water.
BP 428
EP 433
PG 6
JI Ambio
PY 1998
PD SEP
VL 27
IS 6
GA 141JP
J9 AMBIO
UT ISI:000077140400002
ER

PT Journal
AU Steinman, AD
TI Role of algae in the management of freshwater ecosystems
SO JOURNAL OF PHYCOLOGY
BP 725
EP 725
PG 1
JI J. Phycol.
PY 1998
PD OCT
VL 34
IS 5
GA 133AQ
J9 J PHYCOL
UT ISI:000076664600001
ER

PT Journal
AU Goklany, IM
TI Saving habitat and conserving biodiversity on a crowded planet
SO BIOSCIENCE
BP 941
EP 953
PG 15
JI Bioscience
PY 1998
PD NOV
VL 48
IS 11
GA 130RJ
J9 BIOSCIENCE
UT ISI:000076533500011
ER

PT Journal
AU Carpenter, SR
   Turner, MG
TI At last: A journal devoted to ecosystem science
SO ECOSYSTEMS
BP 1
EP 5
PG 5
JI Ecosystems
PY 1998
PD JAN-FEB
VL 1
IS 1
GA 115QL
J9 ECOSYSTEMS
UT ISI:000075676100001
ER

PT Journal
AU Daily, G
   Dasgupta, P
   Bolin, B
   Crosson, P
   du Guerny, J
   Ehrlich, P
   Folke, C
   Jansson, AM
   Jansson, BO
   Kautsky, N
   Kinzig, A
   Levin, S
   Maler, KG
   Pinstrup-Andersen, P
   Siniscalco, D
   Walker, B
TI Policy forum: Global food supply - Food production, population
   growth, and the environment
SO SCIENCE
BP 1291
EP 1292
PG 2
JI Science
PY 1998
PD AUG 28
VL 281
IS 5381
GA 115LQ
J9 SCIENCE
UT ISI:000075666800027
ER

PT Journal
AU Aldy, JE
   Hrubovcak, J
   Vasavada, U
TI The role of technology in sustaining agriculture and the
   environment
SO ECOLOGICAL ECONOMICS
AB Visions of sustainable development often leave unanswered the
   question: What actions taken by the current generation will
   ensure that future generations can meet their economic and
   environmental needs? In this context, we assess the role of
   technology in steering agriculture along a more sustainable
   path. From the agricultural sector's perspective, this requires
   an optimal investment plan for a nation's stock of
   environmental assets that accounts for an intergenerational
   fulfillment of sustainability's dual goals: (1) satisfying food
   and fiber needs at reasonable costs to consumers; and (2)
   providing environmental service flows. In reviewing
   agricultural indicators to assess the nation's performance in
   meeting these goals, we find productivity growth has increased
   while rates of soil erosion, wetland conversion, and pesticide
   application have declined. However, individuals continue to
   demand more environmental services while private markets
   undersupply environmental services. The capacity of the
   agricultural sector to meet food and fiber and environmental
   service demands partially depends on the availability and
   adoption of new technology. Several market impediments explain
   the undersupply of sustainable technologies: (1) firms cannot
   fully appropriate rents from technology development; (2)
   success may vary with farm structure; (3) the heterogeneity of
   the resource base influences adoption; and (4) farmers cannot
   capture the benefits of environmental services. To address
   these market failures, sustainable agriculture policy should:
   (1) support research and development in sustainable
   technologies and provide incentives to encourage adoption; (2)
   ensure that conservation efforts reflect the efficient and
   sustainable allocation of environmental assets; and (3)
   legitimize markets for foods produced under more sustainable
   practices. (C) 1998 Elsevier Science B.V. All rights reserved.
BP 81
EP 96
PG 16
JI Ecol. Econ.
PY 1998
PD JUL
VL 26
IS 1
GA 111DF
J9 ECOL ECON
UT ISI:000075421500007
ER

PT Journal
AU Molles, MC
   Crawford, CS
   Ellis, LM
   Valett, HM
   Dahm, CN
TI Managed flooding for riparian ecosystem restoration - Managed
   flooding reorganizes riparian forest ecosystems along the
   middle Rio Grande in New Mexico
SO BIOSCIENCE
BP 749
EP 756
PG 8
JI Bioscience
PY 1998
PD SEP
VL 48
IS 9
GA 112DH
J9 BIOSCIENCE
UT ISI:000075478500010
ER

PT Journal
AU Carpenter, SR
   Caraco, NF
   Correll, DL
   Howarth, RW
   Sharpley, AN
   Smith, VH
TI Nonpoint pollution of surface waters with phosphorus and
   nitrogen
SO ECOLOGICAL APPLICATIONS
AB Agriculture and urban activities are major sources of
   phosphorus and nitrogen to aquatic ecosystems. Atmospheric
   deposition further contributes as a source of N. These nonpoint
   inputs of nutrients are difficult to measure and regulate
   because they derive from activities dispersed over wide areas
   of land and are variable in time due to effects of weather. In
   aquatic ecosystems, these nutrients cause diverse problems such
   as toxic algal blooms, loss of oxygen, fish kills, loss of
   biodiversity (including species important for commerce and
   recreation), loss of aquatic plant beds and coral reefs, and
   other problems. Nutrient enrichment seriously degrades aquatic
   ecosystems and impairs the use of water for drinking, industry,
   agriculture, recreation, and other purposes. Based on our
   review of the scientific literature, we are certain that (1)
   eutrophication is a widespread problem in rivers, lakes,
   estuaries, and coastal oceans, caused by over-enrichment with P
   and N; (2) nonpoint pollution, a major source of P and N to
   surface waters of the United States, results primarily from
   agriculture and urban activity, including industry; (3) inputs
   of P and N to agriculture in the form of fertilizers exceed
   outputs in produce in the United States and many other nations;
   (4) nutrient flows to aquatic ecosystems are directly related
   to animal stocking densities, and under high livestock
   densities, manure production exceeds the needs of crops to
   which the manure is applied; (5) excess fertilization and
   manure production cause a P surplus to accumulate in soil, some
   of which is transported to aquatic ecosystems; and (6) excess
   fertilization and manure production on agricultural lands
   create surplus N, which is mobile in many soils and often
   leaches to downstream aquatic ecosystems, and which can also
   volatilize to the atmosphere, redepositing elsewhere and
   eventually reaching aquatic ecosystems. If current practices
   continue, nonpoint pollution of surface waters is virtually
   certain to increase in the future. Such an outcome is not
   inevitable, however, because a number of technologies, land use
   practices, and conservation measures are capable of decreasing
   the flow of nonpoint P and N into surface waters. From our
   review of the available scientific information, we are
   confident that: (1) nonpoint pollution of surface waters with P
   and N could be reduced by reducing surplus nutrient flows in
   agricultural systems and processes, reducing agricultural and
   urban runoff by diverse methods, and reducing N emissions from
   fossil fuel burning; and (2) eutrophication can be reversed by
   decreasing input rates of P and N to aquatic ecosystems, but
   rates of recovery are highly variable among water bodies.
   Often, the eutrophic state is persistent, and recovery is slow.
BP 559
EP 568
PG 10
JI Ecol. Appl.
PY 1998
PD AUG
VL 8
IS 3
GA 107PZ
J9 ECOL APPL
UT ISI:000075219300001
ER

PT Journal
AU Postel, SL
TI Water for food production: Will there be enough in 2025?
SO BIOSCIENCE
BP 629
EP 637
PG 9
JI Bioscience
PY 1998
PD AUG
VL 48
IS 8
GA 103GR
J9 BIOSCIENCE
UT ISI:000075150200009
ER

PT Journal
AU Herendeen, RA
TI Monetary-costing environmental services: nothing is lost,
   something is gained
SO ECOLOGICAL ECONOMICS
BP 29
EP 30
PG 2
JI Ecol. Econ.
PY 1998
PD APR
VL 25
IS 1
GA ZQ724
J9 ECOL ECON
UT ISI:000073896700006
ER

PT Journal
AU Lubchenco, J
TI Entering the century of the environment: A new social contract
   for science
SO SCIENCE
AB As the magnitude of human impacts on the ecological systems of
   the planet becomes apparent, there is increased realization of
   the intimate connections between these systems and human
   health, the economy, social justice, and national security. The
   concept of what constitutes "the environment" is changing
   rapidly. Urgent and unprecedented environmental and social
   changes challenge scientists to define a new social contract.
   This contract represents a commitment on the part of all
   scientists to devote their energies and talents to the most
   pressing problems of the day, in proportion to their
   importance, in exchange for public funding. The new and unmet
   needs of society include more comprehensive information,
   understanding, and technologies for society to move toward a
   more sustainable biosphere-one which is ecologically sound,
   economically feasible, and socially just. New fundamental
   research, faster and more effective transmission of new and
   existing knowledge to policy-and decision-makers, and better
   communication of this knowledge to the public will all be
   required to meet this challenge.
BP 491
EP 497
PG 7
JI Science
PY 1998
PD JAN 23
VL 279
IS 5350
GA YT527
J9 SCIENCE
UT ISI:000071616000025
ER

PT Journal
AU Radtke, T
   Wittkopf, TE
TI National Environmental Health Association position on Global
   Climate Change
SO JOURNAL OF ENVIRONMENTAL HEALTH
BP 45
EP &
PG 3
JI J. Environ. Health
PY 1997
PD NOV
VL 60
IS 4
GA YE071
J9 J ENVIRON HEALTH
UT ISI:A1997YE07100011
ER

PT Journal
AU Cleveland, CJ
   Ruth, M
TI When, where, and by how much do biophysical limits constrain
   the economic process? A survey of Nicholas Georgescu-Roegen's
   contribution to ecological economics
SO ECOLOGICAL ECONOMICS
BP 203
EP 223
PG 21
JI Ecol. Econ.
PY 1997
PD SEP
VL 22
IS 3
GA XZ786
J9 ECOL ECON
UT ISI:A1997XZ78600004
ER

PT Journal
AU Johnson, KS
   Gordon, RM
   Coale, KH
TI What controls dissolved iron concentrations in the world ocean?
SO MARINE CHEMISTRY
AB Dissolved (< 0.4 mu m) iron has been measured in 354 samples at
   30 stations in the North and South Pacific, Southern Ocean and
   North Atlantic by the Trace Metals Laboratory at Moss Landing
   Marine Laboratories, These stations are all more than 50 km
   from a continental margin. The global distribution of dissolved
   iron, which is derived from these profiles, is remarkable for
   several reasons, The dissolved iron profiles have a uniform
   shape with a nutrient-like profile at each station.
   Concentrations at the surface are all <0.2 nmol kg(-1) and
   average 0.07 nmol kg(-1). Below 500 m, the average
   concentration is 0.76 nmol kg(-1). The largest value in the
   data set is 1.38 nmol kg(-1). There is no inter-ocean
   fractionation, which is unique for an element with a nutrient-
   like profile. Published estimates of the iron residence time
   are on the order of 100 to 200 yr, indicative of rapid removal.
   Other elements with such short residence times are
   characterized by vertical profiles that decrease with depth and
   deep concentrations that decrease with age as water passes from
   the Atlantic to the Pacific. This is not the case for iron. The
   largest horizontal changes in dissolved iron are observed in
   gradients from the continental margin. There is only a factor
   of three difference between the minimum (0.4 nmol kg(-1)) and
   maximum (1.3 nmol kg(-1)) value in the data set at a depth near
   750 m, where variability is at a maximum. The minimum
   concentrations are found at stations in the remote central
   Pacific and the maximum values occur at stations adjacent to
   the continental margin. The major source of iron in the deep
   sea is generally aeolian deposition. Integrated (surface to 500
   m) concentrations of iron at each station are only weakly
   correlated with the aeolian iron deposition flux, however. This
   contrasts with other elements such as lead that also have
   strong atmospheric sources, These observations lead us to
   conclude that the nutrient-like profile is maintained by a
   mechanism that reduces the scavenging rate of dissolved iron at
   concentrations less than 0.6 nmol kg(-1) This mechanism may be
   complexation by strong iron binding ligands, which have been
   found in both the Atlantic and Pacific at concentrations near
   0.6 nM. This apparent solubility would act to diminish inter-
   ocean fractionation. It would allow a nutrient-like profile to
   develop before scavenging began to remove iron,In order to test
   the concept, we developed a numerical model to make
   quantitative predictions of dissolved iron concentrations from
   place to place. The dissolved iron source in the ocean interior
   is remineralization from sinking particulate organic matter,
   Scavenging removes dissolved iron only at concentrations
   greater than the apparent solubility. The only geographically
   variable parameter in the model is the export flux of carbon
   from the surface layer, which carries iron with it. The model
   generated dissolved iron profiles, based on measured or
   estimated values of the carbon export flux, are in remarkable
   agreement with the observed profiles at all stations from the
   North Atlantic through the Southern Ocean to the North Pacific.
   (C) 1997 Elsevier Science B.V.
BP 137
EP 161
PG 25
JI Mar. Chem.
PY 1997
PD JUL
VL 57
IS 3-4
GA XT791
J9 MAR CHEM
UT ISI:A1997XT79100001
ER

PT Journal
AU Wallace, JS
   Batchelor, CH
TI Managing water resources for crop production
SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON
   SERIES B-BIOLOGICAL SCIENCES
AB Increasing crop production to meet the food requirements of the
   world's growing population will put great pressure on global
   water resources. Given that the vast freshwater resources that
   are available in the world are far from fully exploited,
   globally there should be sufficient water for future
   agricultural requirements. However, there are large areas where
   low water supply and high human demand may lead to regional
   shortages of water for future food production. In these arid
   and semi-arid areas, where water is a major constraint on
   production, improving water resource management is crucial if
   Malthusian disasters are to be avoided. There is considerable
   scope for improvement, since in both dryland and irrigated
   agriculture only about one-third of the available water (as
   rainfall, surface, or groundwater) is used to grow useful
   plants. This paper illustrates a range of techniques that could
   lead to increased crop production by improving agricultural
   water use efficiency. This may be achieved by increasing the
   total amount of water available to plants or by increasing the
   efficiency with which that water is used to produce biomass.
   Although the crash from the Malthusian precipice may ultimately
   be inevitable if population growth is not addressed, the time
   taken to reach the edge of the precipice could be lengthened by
   more efficient use of existing water resources.
BP 937
EP 946
PG 10
JI Philos. Trans. R. Soc. Lond. Ser. B-Biol. Sci.
PY 1997
PD JUL 29
VL 352
IS 1356
GA XQ205
J9 PHIL TRANS ROY SOC LONDON B
UT ISI:A1997XQ20500014
ER

PT Journal
AU Lal, R
TI Degradation and resilience of soils
SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON
   SERIES B-BIOLOGICAL SCIENCES
AB Debate on global soil degradation, its extent and agronomic
   impact, can only be resolved through understanding of the
   processes and factors leading to establishment of the cause-
   effect relationships for major soils, ecoregions, and land
   uses. Systematic evaluation through long-term experimentation
   is needed for establishing quantitative criteria of (i) soil
   quality in relation to specific functions, (ii) soil
   degradation in relation to critical limits of key soil
   properties and processes; and (iii) soil resilience in relation
   to the ease of restoration through judicious management and
   discriminate use of essential input. Quantitative assessment of
   soil degradation can be obtained by evaluating its impact on
   productivity for different land uses and management systems.
   Interdisciplinary research is needed to quantify soil
   degradation effects on decrease in productivity, reduction in
   biomass, and decline in environment quality through pollution
   and eutrophication of natural waters and emission of
   radiatively-active gases from terrestrial ecosystems to the
   atmosphere. Data from long-term field experiments in principal
   ecoregions are specifically needed to (i) establish
   relationships between soil quality versus soil degradation and
   soil quality versus soil resilience; (ii) identify indicators
   of soil quality and soil resilience; and (iii) establish
   critical limits of important properties for soil degradation
   and soil resilience. There is a need to develop and standardize
   techniques for measuring soil resilience.
BP 997
EP 1008
PG 12
JI Philos. Trans. R. Soc. Lond. Ser. B-Biol. Sci.
PY 1997
PD JUL 29
VL 352
IS 1356
GA XQ205
J9 PHIL TRANS ROY SOC LONDON B
UT ISI:A1997XQ20500024
ER

PT Journal
AU Falkenmark, M
TI Society's interaction with the water cycle: A conceptual
   framework for a more holistic approach
SO HYDROLOGICAL SCIENCES JOURNAL-JOURNAL DES SCIENCES
   HYDROLOGIQUES
AB This paper takes as its starting point today's paradoxical
   situation where a global water crisis is threatening a world in
   which water illiteracy is widespread among those expected to
   cope with that crisis. This creates a huge communication
   challenge for hydrologists, having to brief decision makers,
   diplomats and politicians in a manner that is simplistic
   without being water-reductionistic. The paper proposes some
   simple explanatory models, to be used for explaining and
   visualizing fundamental man/water interactions, It also
   discusses environmental sustainability criteria and their
   consequences in terms of the capacity to support water
   dependent populations. Large stress is put on land/water
   interactions. The paper ends with a conceptual framework based
   on the water cycle, distinguishing between rural and urban
   water use, water structures for mobilizing water for such uses,
   side effects, and key points for societal control mechanisms.
BP 451
EP 466
PG 16
JI Hydrol. Sci. J.-J. Sci. Hydrol.
PY 1997
PD AUG
VL 42
IS 4
GA XP220
J9 HYDROLOG SCI J
UT ISI:A1997XP22000002
ER

PT Journal
AU Covich, AP
   Fritz, SC
   Lamb, PJ
   Marzolf, RD
   Matthews, WJ
   Poiani, KA
   Prepas, EE
   Richman, MB
   Winter, TC
TI Potential effects of climate change on aquatic ecosystems of
   the Great Plains of North America
SO HYDROLOGICAL PROCESSES
AB The Great Plains landscape is less topographically complex than
   most other regions within North America, but diverse aquatic
   ecosystems, such as playas, pothole lakes, ox-bow lakes,
   springs, groundwater aquifers, intermittent and ephemeral
   streams, as well as large rivers and wetlands, are highly
   dynamic and responsive to extreme climatic fluctuations. We
   review the evidence for climatic change that demonstrates the
   historical importance of extremes in north-south differences in
   summer temperatures and east-west differences in aridity across
   four large subregions. These physical driving forces alter
   density stratification, deoxygenation, decomposition and
   salinity. Biotic community composition and associated ecosystem
   processes of productivity and nutrient cycling respond rapidly
   to these climatically driven dynamics. Ecosystem processes also
   respond to cultural effects such as dams and diversions of
   water for irrigation, waste dilution and urban demands for
   drinking water and industrial uses. Distinguishing climatic
   from cultural effects in future models of aquatic ecosystem
   functioning will require more refinement in both climatic and
   economic forecasting. There is a need, for example, to predict
   how long-term climatic forecasts (based on both ENSO and global
   warming simulations) relate to the permanence and productivity
   of shallow water ecosystems. Aquatic ecologists, hydrologists,
   climatologists and geographers have much to discuss regarding
   the synthesis of available data and the design of future
   interdisciplinary research. (C) 1997 by John Wiley gi Sons,
   Ltd.
BP 993
EP 1021
PG 29
JI Hydrol. Process.
PY 1997
PD JUN 30
VL 11
IS 8
GA XL947
J9 HYDROL PROCESS
UT ISI:A1997XL94700009
ER

PT Journal
AU Vitousek, PM
   Mooney, HA
   Lubchenco, J
   Melillo, JM
TI Human domination of Earth's ecosystems
SO SCIENCE
AB Human alteration of Earth is substantial and growing. Between
   one-third and one-half of the land surface has been transformed
   by human action; the carbon dioxide concentration in the
   atmosphere has increased by nearly 30 percent since the
   beginning of the Industrial Revolution; more atmospheric
   nitrogen is fixed by humanity than by all natural terrestrial
   sources combined; more than half of all accessible surface
   fresh water is put to use by humanity; and about one-quarter of
   the bird species on Earth have been driven to extinction. By
   these and other standards, it is clear that we live on a human-
   dominated planet.
BP 494
EP 499
PG 6
JI Science
PY 1997
PD JUL 25
VL 277
IS 5325
GA XM867
J9 SCIENCE
UT ISI:A1997XM86700030
ER

PT Journal
AU Matson, PA
   Parton, WJ
   Power, AG
   Swift, MJ
TI Agricultural intensification and ecosystem properties
SO SCIENCE
AB Expansion and intensification of cultivation are among the
   predominant global changes of this century. Intensification of
   agriculture by use of high-yielding crop varieties,
   fertilization, irrigation, and pesticides has contributed
   substantially to the tremendous increases in food production
   over the past 50 years. Land conversion and intensification,
   however, also alter the biotic interactions and patterns of
   resource availability in ecosystems and can have serious local,
   regional, and global environmental consequences. The use of
   ecologically based management strategies can increase the
   sustainability of agricultural production while reducing off-
   site consequences.
BP 504
EP 509
PG 6
JI Science
PY 1997
PD JUL 25
VL 277
IS 5325
GA XM867
J9 SCIENCE
UT ISI:A1997XM86700032
ER

PT Journal
AU Meyer, JL
TI Stream health: Incorporating the human dimension to advance
   stream ecology
SO JOURNAL OF THE NORTH AMERICAN BENTHOLOGICAL SOCIETY
AB A healthy stream is an ecosystem that is sustainable and
   resilient, maintaining its ecological structure and function
   over time while continuing to meet societal needs and
   expectations. The concept described in this paper explicitly
   incorporates both ecological integrity (maintaining structure
   and function) and human Values (what society Values in the
   ecosystem). Stream ecologists who want their research to
   contribute to improving conditions in flowing waters require
   concepts Like stream health, which will stimulate research in
   directions that will be more effective in restoring and
   preserving the unique organisms and ecosystems they study.
   Determining what is a healthy stream requires integration of
   stream ecology with disciplines such as economics and political
   science, because a concept of stream health must take into
   account the human attitudes and social institutions that are a
   part of the stream's societal watershed. New and fruitful
   directions for stream research lie in developing operational
   measures of stream health, which include the human dimension
   and move beyond identifying symptoms of ecological stress, and
   in elucidating the ecological processes and human actions that
   maintain stream health.
BP 439
EP 447
PG 9
JI J. N. Am. Benthol. Soc.
PY 1997
PD JUN
VL 16
IS 2
GA XD620
J9 J N AMER BENTHOL SOC
UT ISI:A1997XD62000011
ER

PT Journal
AU Pimm, SL
TI The value of everything
SO NATURE
BP 231
EP 232
PG 2
JI Nature
PY 1997
PD MAY 15
VL 387
IS 6630
GA WZ167
J9 NATURE
UT ISI:A1997WZ16700022
ER

PT Journal
AU Myers, N
TI Consumption: Challenge to sustainable development ...
SO SCIENCE
BP 53
EP 55
PG 3
JI Science
PY 1997
PD APR 4
VL 276
IS 5309
GA WR386
J9 SCIENCE
UT ISI:A1997WR38600040
ER

PT Journal
AU Dodds, WK
TI Distribution of runoff and rivers related to vegetative
   characteristics, latitude, and slope: A global perspective
SO JOURNAL OF THE NORTH AMERICAN BENTHOLOGICAL SOCIETY
AB The geographic distribution of streams on earth can be
   associated with terrestrial vegetation, slope, and latitude,
   among other factors. Classifying flowing water habitats by
   associated vegetative cover is useful because factors such as
   downstream transport of organic carbon (C), sediments,
   nutrients, and other dissolved or suspended materials are
   influenced heavily by the vegetative characteristics of the
   watershed. Global datasets with 1-degree spatial resolution
   were analyzed to characterize both Volume of runoff and number
   of mapped rivers associated with each of 14 classes of
   vegetation, and how runoff is influenced by latitude and slope.
   The Vegetation classes (land cover) were ranked in deceasing
   order with respect to runoff. About 30% of the global runoff
   originates from broadleaf evergreen forest, followed by wooded
   C-4 grassland (14.8%), cultivated land (8.9%), coniferous
   forest and woodland (8.3%), ice (7.8%), wooded C-3 grassland
   (6.0%), mixed coniferous and broadleaf deciduous forest (5.4%),
   C-3 grassland (5.3%), tundra (4.5%), high latitude deciduous
   forest and woodland (3.9%), broadleaf deciduous forest and
   woodland (2.3%), C-4 grassland (1.7%), shrubs and bare ground
   (1.4%), and desert and bare ground (0.5%). Numbers of mapped
   rivers followed a similar pattern, except that broadleaf
   evergreen forests did not dominate, and tundra habitats were
   much more important. Counts of intermittent rivers were
   generally highest in the areas with the lowest runoff. River
   counts are likely to be less reliable than runoff estimates
   because they rely upon the subjective judgment of
   cartographers. Equatorial and northern temperate regions
   accounted for the greatest proportion of total runoff A weak
   positive relationship occurred between slope and runoff. This
   analysis may assist investigators in determining how well their
   results can be extrapolated beyond regional scales.
BP 162
EP 168
PG 7
JI J. N. Am. Benthol. Soc.
PY 1997
PD MAR
VL 16
IS 1
GA WM593
J9 J N AMER BENTHOL SOC
UT ISI:A1997WM59300028
ER

PT Journal
AU Pimentel, D
   Houser, J
   Preiss, E
   White, O
   Fang, H
   Mesnick, L
   Barsky, T
   Tariche, S
   Schreck, J
   Alpert, S
TI Water resources: Agriculture, the environment, and society
SO BIOSCIENCE
BP 97
EP 106
PG 10
JI Bioscience
PY 1997
PD FEB
VL 47
IS 2
GA WD704
J9 BIOSCIENCE
UT ISI:A1997WD70400008
ER

PT Journal
AU Farrell, A
TI Sustainability and the design of knowledge tools
SO IEEE TECHNOLOGY AND SOCIETY MAGAZINE
BP 11
EP 20
PG 10
JI IEEE Technol. Soc. Mag.
PY 1996
PD WIN
VL 15
IS 4
GA VX326
J9 IEEE TECHNOL SOC MAG
UT ISI:A1996VX32600004
ER

PT Journal
AU Naylor, RL
TI Energy and resource constraints on intensive agricultural
   production
SO ANNUAL REVIEW OF ENERGY AND THE ENVIRONMENT
AB This review explores the potential energy, soil, and water
   constraints on highly productive agricultural systems. It
   focuses on the process of agricultural intensification during
   the past 50 years, and it shows that multiple constraints-as
   opposed to a single constraint, such as energy-are needed to
   assess the future sustainability of intensive agricultural
   production. Recent studies documenting changes in total factor
   productivity based on long-term experimental trials and held
   surveys are discussed in detail. The results of these studies
   are worrisome; they indicate that degradation in soil quality
   and in the overall natural resource base may threaten the long-
   run viability of several of the world's most intensive
   agricultural systems. Other studies are reviewed that support a
   more optimistic view of resource availability and the ability
   of improved technology and management to overcome these
   physical constraints. However, the combined evidence suggests
   that the increase in agricultural prices required to induce the
   necessary changes in technology could be devastating to low-
   income households. Most of the world's poor consume more
   agricultural output than they produce, and they spend up to 80%
   of their incomes on food.
BP 99
EP 123
PG 25
JI Annu. Rev. Energ. Environ.
PY 1996
VL 21
GA VW793
J9 ANNU REV ENERG ENVIRON
UT ISI:A1996VW79300006
ER

PT Journal
AU Harte, J
TI Feedbacks, thresholds and synergies in global change:
   Population as a dynamic factor
SO BIODIVERSITY AND CONSERVATION
AB The role of feedbacks, thresholds, and synergies in
   environmental science, and their implications for environmental
   degradation under a growing human population, are reviewed. A
   detailed analysis of the impacts of climate change on water
   resources is used to elucidate mechanisms by which
   nonlinearities arise in environmental science. Additional
   examples are drawn from analysis of soil degradation and non-
   climate related degradation of water resources. The often-
   assumed notion that impacts will grow in proportion to
   population size is shown to be overly optimistic. In
   particular, feedbacks, thresholds, and synergies among multiple
   threats, tend to amplify risk and cause environmental impacts
   to grow considerably faster than linearly in population size,
   even when the per-capita living standard and the technological
   systems deployed to achieve that living standard are assumed to
   remain constant.
BP 1069
EP 1083
PG 15
JI Biodivers. Conserv.
PY 1996
PD SEP
VL 5
IS 9
GA VH808
J9 BIODIVERS CONSERV
UT ISI:A1996VH80800005
ER