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CHAPTER 8. ECOSYSTEMS
|This chapter's contents...
Question 8.1: What are the most important feedbacks between ecological
systems and global change (especially climate), and what are their
Question 8.2: What are the potential consequences of global change
for ecological systems?
Question 8.3: What are the options for sustaining and improving
ecological systems and related goods and services, given projected
National and International Partnerships
Ecosystems shape our societies and nations by providing essential
renewable resources and other benefits. They sustain human life by
providing the goods and services it depends on, including food, fiber,
shelter, energy, biodiversity, clean air and water, recycling of elements,
and cultural, spiritual, and aesthetic returns. Ecosystems also affect the
climate system by exchanging large amounts of energy, momentum, and
greenhouse gases with the atmosphere. The goal of the Ecosystems element
of the U.S. Climate Change Science Program (CCSP) is to understand and be
able to project the potential effects of global change on ecosystems, the
goods and services ecosystems provide, and ecosystem links to the climate
system (see Box 8-1 and Figure 8-1).
Box 8-1. Two Key Definitions
Ecosystem - a community (i.e., an assemblage of populations of
plants, animals, fungi, and microorganisms that live in an environment
and interact with one another, forming together a distinctive living
system with its own composition, structure, environmental relations,
development, and function) and its environment treated together as a
functional system of complementary relationships and transfer and
circulation of energy and matter.
Ecosystem Goods and Services - through numerous biological,
chemical, and physical processes, ecosystems provide both goods and
services. Goods include food, feed, fiber, fuel, pharmaceutical
products, and wildlife. Services include maintenance of hydrologic
cycles, cleansing of water and air, regulation of climate and weather,
storage and cycling of nutrients, provision of habitat, and provision of
beauty and inspiration. Many goods pass through markets, but services
Figure 8-1: Key linkages and feedbacks
between ecological systems, human systems (societies), and the climate
system and atmospheric composition. Spatial scales are implicit and
span from local to global. Humans manage some ecosystems intensively
and others lightly. All ecosystems are affected to some degree,
positively or negatively, by major global changes.
Global change is altering the structure and functioning of ecosystems,
which in turn affects availability of ecological resources and benefits,
changes the magnitude of some feedbacks between ecosystems and the climate
system, and could affect economic systems that depend on ecosystems.
Research during the last decade focused on the vulnerability of ecosystems
to global change and contributed to assessments of the potential effects
of global change on ecological systems at multiple scales.
We now know that effects of environmental changes and variability may
be manifested in complex, indirect, and conflicting ways. For example,
warming may enhance tree growth by extending growing season length (in
temperate and cool regions), but pathogens better able to survive the
winter because of higher temperature may decrease forest productivity and
increase vulnerability of forests to disturbances such as fire. Subtle
changes in winds over the ocean can affect currents which in turn may
alter the ranges and population sizes of fish species and increase or
decrease fish catches. Whether environmental changes are anthropogenic or
natural in origin, human societies face substantial challenges in ensuring
that ecosystems sustain the goods and services on which we depend for our
quality of life and survival itself.
Figure 8-2: Landscapes and ecosystems are
managed (some intensively, some lightly) by humans to produce grain,
timber, and cattle, among many other goods and services desired by
societies. For example, according to the Food and Agriculture Organization
of the United Nations, 96% of the protein and 99% of the energy (usable
calories) in the U.S. food supply come from terrestrial ecosystems (the
remainder is derived from the ocean). Globally, about 94% of protein and
99% of energy in the human food supply come from terrestrial ecosystems.
Photo sources: Tim McCabe (top and middle) and Jeff Vanuga (bottom),
USDA-Natural Resources Conservation Service.
During the next 10 years, research on ecosystems will focus on two
How do natural and human-induced changes in the environment
affect the structure and functioning of ecosystems at a range of
spatial and temporal scales, including those processes that can in
turn influence regional and global climate?
What options does society have to ensure that ecosystem goods and
services will be sustained or enhanced in the face of potential
regional and global environmental changes?
Research should be focused on building the scientific foundation needed
for an enhanced capability to forecast effects of multiple environmental
changes (such as concurrent changes in climate, atmospheric composition,
land use, pollution, invasive species, and resource management practices)
on ecosystems, and for developing products for decision support in
managing ecosystems. Near-term priorities will be placed on economically
important ecosystems (e.g., Figure 8-2) and special studies relevant to
regions where abrupt environmental changes or threshold responses by
ecosystems may occur. Investigations will emphasize changes in ecosystem
structure and functioning and changes in the frequency and intensity of
disturbance processes anticipated to have significant consequences for
society during the next 50 years, including altered productivity, changes
in biodiversity and species invasions (including pests and pathogens), and
changes in carbon, nitrogen, and water cycles.
Ensuring the desired provision of ecosystem goods and services will
require understanding of interactions among basic ecosystem processes and
developing approaches to reduce the vulnerabilities to, or take advantage
of opportunities that arise because of, global and climatic changes.
Scientific research can contribute to this societal goal by addressing
three questions that focus on linkages and feedbacks between ecosystems
and drivers of global change, important consequences of global change for
ecological systems, and societal options for sustaining and enhancing
ecosystem goods and services as environmental conditions change. This
research will produce critical knowledge and provide a forecasting
capability that will continuously improve decisionmaking for resource
management and policy development.
Question 8.1: What are the most important
feedbacks between ecological systems and global change (especially
climate), and what are their quantitative relationships?
State of Knowledge
Biological, chemical, and physical processes occurring in ecosystems
affect and are affected by weather and climate in many ways. For example,
ecosystems (and the organisms they contain) exchange large amounts of
greenhouse gases with the atmosphere, including water vapor, carbon
dioxide (CO2), methane (CH4), and nitrous oxide (N2O).
Moreover, the reflection (or absorption) of solar radiation by ecosystems
is important to the temperature of Earth's surface. Linkages among the
physical, chemical, and biological components of ecosystems are important
on short (minutes to days) and long (years to millennia) time scales, as
well as local to global spatial scales.
Global change has the potential to alter ecosystem structure (e.g.,
amount of leaf area, plant height, or species composition) and ecosystem
functioning (e.g., rates of evapotranspiration, carbon assimilation, and
biogeochemical cycling), and those potential changes in ecosystems might
enhance or reduce global change through numerous feedback mechanisms (see
Box 8-2). In addition to its direct linkages with ecological systems,
global change could alter human actions that affect the structure,
functioning, and spatial distribution of ecosystems, which in turn could
alter important feedbacks from ecological systems to climate.
Box 8-2. Feedbacks
A feedback from an ecosystem to climate or atmospheric composition
occurs when a change in climate or atmospheric composition causes a
change in the ecosystem that in turn alters the rate of the "original"
change in climate or atmospheric composition. A positive feedback
intensifies the original change whereas a negative feedback slows
the original change (but does not change its sign). A positive feedback
could occur, for example, if warming and drying (caused by increasing
atmospheric CO2 concentration) of high latitude terrestrial
ecosystems containing large amounts of carbon in plants and soils (e.g.,
tundra and peatland) resulted in greater ecosystem respiration, and this
increased the rate of atmospheric CO2 increase, which then
accelerated the warming and drying. A negative feedback might occur, for
example, if increasing atmospheric CO2 concentration
increased primary production in aquatic and/or terrestrial ecosystems,
and that increased production resulted in greater carbon storage on land
and in waters. This could slow the increase in radiative forcing from
greenhouse gases in the atmosphere.
The most important feedbacks, either positive or negative, are likely
Altered ecosystem/atmosphere exchanges of greenhouse gases
Altered releases of aerosols from ecosystems (including black
carbon and sulfur resulting from controlled and uncontrolled ecosystem
Altered releases of volatile organic compounds from ecosystems
Changes in surface albedo resulting from changes in ecosystems
Changes in the fraction of absorbed solar radiation that drives evapotranspiration compared to directly heating the plants and soils
in terrestrial ecosystems
Long-term changes in ecosystem structure or shifts in the
geographic distribution and extent of major ecosystem types.
How might changes in temperature and precipitation affect net
ecosystem exchanges (or timing or geographic distribution of those
exchanges) of greenhouse gases and aerosols?
How might changes in climate and atmospheric composition, in
combination with other factors such as land-use/cover changes, affect
ecosystem albedo, evapotranspiration, and nutrient cycling?
How might changes in regional air quality (including chemicals
and aerosols released from industrial sources or ecosystem
disturbances such as wildfires and crop residue burning), in
combination with climatic variability and change, affect ecosystem albedo and exchange of greenhouse gases?
How might changes in ecosystems alter Earth's radiation balance,
fresh water cycle, and carbon cycle, and could any such alterations
contribute to abrupt climate change?
How might human activities affect the release or uptake of
greenhouse gases by ecosystems?
Research needs include improved experimental facilities and
capabilities for making measurements in those facilities, ecosystem
models, and ecosystem observing capabilities (and their related
measurements) at multiple scales (to scale up from point observations with
remotely sensed data). Initial efforts will be directed at enhancing
existing capabilities and improving use of existing data streams. Studies
should include identification of early indicators of changes in ecosystems
that may be important to feedbacks to climate and atmospheric composition.
Specific research needs include:
Field and controlled-environment experimental facilities and
long-term ecological observing systems at multiple locations to
quantify ecosystem-environment interactions (focusing on ecosystem
greenhouse gas and energy exchanges) to better parameterize,
calibrate, and evaluate models of land-ocean-atmosphere chemistry
feedbacks. Primary linkages are to the
Carbon Cycle and
research elements to share data and experimental sites and facilities.
Spatially explicit ecosystem models capable of representing
complex interactions between diverse ecosystems and their physical and
Models that link remote sensing of land surface albedo to changes
in the spatial distribution of ecosystems and exchanges of mass,
energy, and momentum for implementation in climate models. It is
anticipated that these models will be developed in collaboration with
the Water Cycle and Carbon Cycle research elements. A primary linkage
is to the Land-Use/Land-Cover Change research element to provide
model-based projections of future land cover.
Social science research to explore human factors in
ecosystem-climate linkages and feedbacks. The
research element must supply information on the magnitude and
significance of the primary human drivers of global change.
Reports presenting a synthesis of current knowledge of observed
and potential (modeled) feedbacks between ecosystems and climatic
change to aid understanding of such feedbacks and identify knowledge
gaps for research planning [2-4 years]; Arctic Climate Impact
Assessment [2 years].
Definition of the initial requirements for ecosystem observations
to quantify feedbacks to climate and atmospheric composition, to
enhance existing observing systems, and to guide development of new
observing capabilities [2-4 years]. This will provide key input to the
Observing and Monitoring component of the program.
Quantification of important feedbacks from ecological systems to
climate and atmospheric composition to improve the accuracy of climate
projections [beyond 4 years]. This product will be needed by the
Climate Variability and Change research element to ensure inclusion of
appropriate ecological components in future climate models.
Question 8.2: What are the potential consequences of
global change for ecological systems?
State of Knowledge
Many research programs that support long-term observations (e.g.,
forest productivity, ultraviolet-B (UV-B) radiation received by
ecosystems, greenhouse gas concentrations and fluxes, atmospheric nitrogen
deposition, nutrient loading, fisheries, and the spread of invasive
species) have unambiguously established that large-scale ecological
changes are occurring, and there is considerable evidence that some of
those changes are the result of ecological responses to climatic
variability and change. For example, recent warming has been indicated as
potentially linked to longer growing seasons (i.e., period of leaf
display) in temperate and boreal terrestrial ecosystems, grass species
decline, changes in aquatic biodiversity, and coral bleaching (IPCC,
2001b; and see Figures 8-3 and 8-4). Natural modes of climatic variability
(e.g., El Nino-Southern Oscillation,
North Atlantic Oscillation, and
Pacific Decadal Oscillation) are known to impact plankton and fisheries,
such as sardine, anchovies, and salmon. Soil-borne plant pathogens and
parasitic nematodes have been found to move northward (in the Northern
Hemisphere) with increased surface temperature. Because survival and
spread of pathogens and their vectors (carriers) depend on climate and
weather, climatic change and increased natural climatic variability would
be expected to affect disease-causing organisms that could alter the
ecological status of fauna and flora. These and other observations and
expectations have come from both experiments and in situ
Figure 8-3: When stressed, corals frequently expel their symbiotic
algae en mass, leaving coral bereft of pigmentation and appearing nearly
transparent on the animal's white skeleton, a phenomenon referred to as
coral bleaching. This image of bleached coral colonies was obtained during
the January-March 2002 coral bleaching event in
Great Barrier Reef,
Australia, the worst bleaching event on record for this reef. Bleaching
events reported prior to the 1980s were generally attributed to local
phenomena (e.g., major storm events, sedimentation, or pollution), but
since then, a direct relationship between bleaching events and elevated
ocean temperature (see Figure 8-4) was found. Source: Ray Berkelmans,
Australian Institute of Marine Science.
Figure 8-4: Top: Annual global sea-surface temperature (SST)
anomalies relative to the 1880-2002 mean based on in situ and
satellite measurements. The warmest annual global SST occurred in 1998.
Bottom: Incidences of coral bleaching were influenced by unprecedented
SST anomalies in 1998 due to a severe El Nino event as shown by this
satellite retrospective annual composite monthly mean coral bleaching
"HotSpot" chart for 1998. A coral bleaching HotSpot is defined as an SST
anomaly above a coral-bleaching threshold SST climatology. HotSpot charts
illustrate the magnitude and spatial distribution of thermal stresses that
may contribute to coral bleaching. This chart was derived from the
NOAA/NASA 9-km satellite AVHRR (Advanced Very High Resolution Radiometer)
Oceans Pathfinder SST data set, the most refined available. Source: NOAA
National Climatic Data Center.
Most ecosystems are now
subject to multiple environmental changes. The dynamics and interactions
of those changes and the consequences for ecological systems are poorly
understood (NRC, 1999a). Recent reviews (e.g.,
IPCC, 2001b) summarized the
range of observed and potential consequences of combinations of changes in
climate, atmospheric composition, and local drivers (e.g., invasive
species, pollution, and physical habitat modification) on ecological
systems. For example, in aquatic systems, alterations in wind speeds and
precipitation patterns, in combination with increased air temperature,
would affect water column stratification and circulation, resulting in
changes in the rates of nutrient supply and productivity at all trophic
levels. For terrestrial ecosystems, a large knowledge base of effects of a
change in a single environmental parameter exists, but effects of multiple
changes on most ecosystem processes are uncertain (e.g.,
Nonetheless, we know, for example, that interactions among changes in
temperature, precipitation, and fire regimes can influence vulnerability
to invasive species in terrestrial ecosystems. We also know that elevated
atmospheric CO2 concentration can sometimes eliminate the
negative effects of elevated tropospheric ozone (O3)
concentration and warming on crop yields, and vice versa.
Documented effects of environmental changes on net
primary production (NPP) of terrestrial ecosystems.
Environmental Change Factor
|Increasing atmospheric CO2
|Increasing tropospheric O3 concentration
||Stimulation or inhibition*
|Changes in regional hydrologic cycles
||Inhibition or stimulation*
|Increasing atmospheric nitrogen
||Stimulation or no
|Increasing land-surface UV-B radiation
||No effect or inhibition*
|Combinations of the above
|| Highly uncertain for most combinations and ecosystems
|* Depends on other factors and circumstances. For example, warming
might stimulate NPP in a presently cool region, but inhibit NPP in a
presently warm region.
Illustrative Research Questions
How might the combination of increasing CO2
concentration, increasing tropospheric O3 concentration,
and warming affect yield of major U.S. crops?
What are the effects of changes in atmospheric CO2
concentration, precipitation, and temperature on the structure and
functioning of boreal forests?
What are the effects of increased UV-B radiation, increased rates
of sea level rise, temperature changes, and elevated concentration of
CO2 on biodiversity, structure, and functioning of coastal
Does climatic variability and change modify effects of other
changes (e.g., pollution, invasive species, and changes in land,
water, and resource use) on ecosystems?
How will basin-scale changes in physical forcing mechanisms
affect the productivity, distribution, and abundance of plankton,
fish, seabird, and marine mammal populations in coastal marine
How do changes in climate and weather (both its variability and
extremes) affect the ecology and epidemiology of infectious pathogens,
dissemination by their vectors, and susceptibility of the humans,
animals, and plants that are their hosts?
How rapidly might ecosystems, or individual species, move poleward and to higher elevations in response to regional warming?
What are the effects of increasing atmospheric CO2
concentration, warming, and sea-level rise on wetland plant
contributions to soil elevation and shoreline stability?
How will changes in the hydrologic cycle affect aquatic, riverine, and inland wetland ecosystems?
Figure 8-5: Scientific user facility for the study of effects of
simultaneous changes in concentrations of CO2 and O3
on the structure and functioning of northern hardwood tree stands. This
facility is located near Rhinelander, Wisconsin, and is supported by
USDA, NSF, and others. Source: North Central Station, U.S. Forest Service.
Identifying and quantifying the rates and consequences of global change
for ecological systems is essential for appropriately evaluating options
for responding to such changes. Determining the most important and
societally relevant effects of global change on ecosystems will require
collaboration among physical, biological, and social scientists and an
improved understanding of complex interactions between natural and human
disturbances and climatic variability. Near-term research priorities
should include both ecosystems of special importance to society (e.g.,
major crops, commercial forests, and parks and preserves) and regions
where abrupt changes or threshold responses may occur, such as
high-altitude and high-latitude ecosystems and transitional zones between
ecosystems (e.g., forest-grassland, agriculture-native prairie, ocean
boundary currents, coastal zones, and/or rural-urban interfaces). Field
studies should, where appropriate, share experimental facilities and
research sites (e.g., Figure 8-5) with the Carbon Cycle and Water Cycle
research elements. High-resolution ocean shoreline topographic data will
be needed to adequately project effects of sea level rise on coastal
Specific research needs include:
Experiments to study the interactive effects of climatic
variability and change, elevated atmospheric CO2
concentration, nutrient/pollution deposition, increased UV-B
radiation, invasive species, and land use on key species and intact
ecosystems. Understanding the effects of warming, increasing CO2
concentration, and changing precipitation on the structure and
functioning of ecosystems will require improved projections of the
rate of change of climate and atmospheric CO2
concentration. These improved projections will be provided by the
Climate Variability and Change and Carbon Cycle research elements, and
will be needed to both design experiments and interpret experimental
Quantification of biomass, species composition, and community
structure of terrestrial and aquatic ecosystems in relation to
disturbance patterns, through observations, modeling, and process
studies. Information on disturbance patterns will require inputs from
the Land-Use/Land-Cover Change research element and information on
biomass (carbon) pools will require inputs from the Carbon Cycle
Experiments and models that can identify threshold responses of
ecosystems and species to potential climatic variability and change.
Studies to connect paleontological, historical, contemporary, and
future changes and rates of change in ecosystem structure and
functioning. Long-term data sets and projections of climate and the
spatial distribution and intensity of various land uses will be
required from the Climate Variability and Change and the
Land-Use/Land-Cover Change research elements.
Maintenance and enhancement of long-term observations to track
changes in seasonal cycles of productivity, species distributions and
abundances, and ecosystem structure. Improved spatial, spectral, and
especially temporal resolution in observing systems from the Observing
and Monitoring research element is needed to better understand and
project ecological processes to parameterize models and verify model
Determination of organismal rates of adaptation and the magnitude
of subsequent effects on community structure in relation to rates of
Investigations of the link between biodiversity and ecosystem
functions and resulting services.
Studies of effects of changes in "upstream" ecosystems on
receiving-water ecosystems. Primary linkages are to the Water Cycle
and Land-Use/Land-Cover Change research elements.
Data from field experiments quantifying aboveground and
belowground effects of elevated CO2 concentration in
combination with elevated O3 concentration on the structure
and functioning of agricultural [less than 2 years], forest [2-4
years], and aquatic [beyond 4 years] ecosystems. Some of the data will
be obtained in collaboration with the Carbon Cycle research element.
Reports describing the potential consequences of global and
climatic changes on selected arctic, alpine, wetland, riverine, and
estuarine and marine ecosystems; selected forest and rangeland
ecosystems; selected desert ecosystems; and the Great Lakes based on
available research findings, to alert decisionmakers to potential
consequences for these ecosystems [2-4 years]. Results will be
important input to the Human Contributions and Responses research
Field experiments (and user facilities) in place to study
responses of ecosystems (including any changes in nutrient cycling) to
combinations of elevated CO2 concentration, warming, and
altered hydrology, with data collection underway. Such facilities will
be essential for evaluating ecosystem models used to assess effects of
climatic variability and change on ecosystem goods and services (and
therefore input to the Human Contributions and Responses research
element), as well as feedbacks to the climate system and atmospheric
composition (and therefore input to the Climate Variability and Change
and the Atmospheric Composition research elements). Where appropriate,
these research facilities will be developed in collaboration with the
Carbon Cycle research element [2-4 years].
Synthesis of known effects of increasing CO2, warming,
and other factors (e.g., increasing tropospheric O3) on
terrestrial ecosystems based on multifactor experiments [2-4 years].
This synthesis will be developed with the Carbon Cycle research
A new suite of indicators of coastal and aquatic ecosystem change
and health based on output from ecosystem models, long-term
observations, and process studies [2-4 years].
Definition of the initial requirements for observing systems to
monitor the health of ecosystems, to serve as an early warning system
for unanticipated ecosystem changes, and to verify approaches for
modeling and forecasting ecosystem changes [2-4 years]. This will be
an important input to the Observing and Monitoring component of the
Development of data and predictive models determining the
sensitivity of selected organisms and their assemblages to changes in
UV-B radiation and other environmental variables relative to
observations of UV-B radiation in terrestrial, aquatic, and wetland
habitats [beyond 4 years].
Development of data and predictive models determining the
sensitivity of selected organisms and their assemblages to
contaminants and other environmental variables in terrestrial,
aquatic, and wetland habitats [beyond 4 years].
Spatially explicit ecosystem models at regional to global scales,
based on data from remote sensing records and experimental
manipulations focused on effects of interactions among global change
variables, to improve our understanding of contemporary and historical
changes in ecosystem structure and functioning [beyond 4 years].
Enhanced understanding of potential consequences of major global
changes on key ecological systems [beyond 4 years].
Question 8.3: What are the options for sustaining
and improving ecological systems and related goods and services, given
projected global changes?
State of Knowledge
Experiments and observations have demonstrated linkages between climate
and ecological processes, indicating that future changes in climate could
alter the flow of ecosystem goods and services (IPCC, 2001b). Several
specific mitigation and adaptation measures have been identified and
evaluated, including integrated land and water management; genetic
selection of plants and livestock; multiple cropping systems; multiple use
of freshwater and terrestrial ecosystems; programs for protection of key
habitats, landscapes, and/or species; intervention programs (e.g., captive
breeding and (re)introduction programs); more efficient use of natural
resources; and institutional and infrastructure improvements (e.g., market
responses, crop insurance, and water flow and supply management) (IPCC,
It is clear that management practices can affect climate-related
ecosystem goods and services. For example, management can influence the
emission of greenhouse gases and aerosols from ecosystems; the rate at
which ecosystems gain or lose carbon, nitrogen, phosphorus, and other
elements as well as the total amount of those elements stored; the
radiation balance of ecosystems (i.e., land surface albedo); and the
production of goods valued by humans. While some management strategies
have been studied, society's knowledge and ability to manage the broad
array of ecosystem goods and services in the context of increasing and
potentially conflicting demands (e.g., increasing food and fiber
production while storing more carbon in soils and reducing CH4
emissions) is very limited.
Illustrative Research Questions
How can aquatic ecosystems be managed to balance the production
and sustenance of ecosystem services across multiple demands (e.g.,
management of rivers to supply freshwater for drinking, irrigation,
recreation, hydropower, and fish), considering potential effects of
interacting environmental changes?
How can terrestrial ecosystems such as rangelands, forests,
woodlands, and croplands be managed (e.g., maintaining wildlife
corridors) to balance the production and sustenance of ecosystem goods
and services across multiple demands (e.g., food, fiber, fuel, fodder,
recreation, biodiversity, biogeochemical cycles, tourism, and flood
control), considering the future effects of interacting environmental
What options exist for society to preserve genetic diversity;
respond to species migrations, invasions, and/or declines; and manage
changing disease incidence and severity in the face of global change?
How can coral reefs be managed for tourism, erosion protection, refugia for commercially and recreationally important species, and
biodiversity, considering potential global changes?
How can coastal and estuarine ecosystems be managed to sustain
their productivity and use in the face of existing stresses (e.g.,
pollution, invasive species, and extreme natural events) and potential
What options exist for responding to abrupt changes in ecological
What are the effects of management practices on global and
regional environments (e.g., atmospheric chemistry, water supply, and
water quality), nitrogen cycling, and the health, productivity, and
resilience of ecosystems?
Much ecosystem management for the foreseeable future will proceed with
imperfect knowledge about the effects of multiple global change processes
and about fundamental aspects of ecosystem structure and functioning.
Routine monitoring (e.g., Figure 8-6), scientific evaluation, and feedback
from managers could enable adaptive shifts in management strategies as
knowledge about an ecological system grows, and at the same time will
provide important opportunities for scientists to test hypotheses about
ecosystem responses to environmental change. Substantial improvements in
modeling capabilities are also needed to develop and deploy effective
options to maintain and enhance the supply of critical goods and services
and to evaluate alternative management options under changing
environmental conditions. Modeling alternative management options will
require evaluation of the influence of societal demands on ecosystems.
Specific research needs include:
Improve understanding of causal mechanisms that drive complex
changes in ecological systems, including robust indicators and likely
rates of change, to develop predictive management tools such as
ecological forecasting models using socioeconomic data as an input.
Identify ecological systems susceptible to abrupt environmental
changes with potentially significant (positive or negative) impacts on
goods and services in order to develop adequate mitigation and
Evaluate the use of ecological information and projections in decisionmaking.
Apply information on water quantity, quality, and delivery from
the Water Cycle research element and frequency of extreme events from
the Climate Variability and Change research element to evaluate
ecosystem performance and management options.
Develop and evaluate local- to regional-scale ecosystem-climate
Assess the direct and indirect ecological effects and economic
costs of management practices through regular monitoring, evaluation,
and experimentation with a goal of enabling adaptive shifts in
Explore obstacles to the implementation of ecosystem management
Understand consequences of harvest practices in marine fisheries
on changes in the age structure of the harvested populations, the
structure and productivity of fisheries ecosystems, and responses of
fisheries to global change.
MILESTONES, Products, and Payoffs
For forests, agricultural systems, rangelands, wetlands,
fisheries, and coral reefs, conduct preliminary comparisons of the
effectiveness of selected management practices in selected regions
focusing on greenhouse gas exchange, health, productivity, and
biodiversity of the targeted ecosystems and their goods and services
under changing environmental conditions [2-4 years].
Initiation of development of decision support tools relevant to
regions where abrupt or threshold ecological responses may occur,
especially high-altitude and high-latitude ecosystems and transitional
zones between ecosystems (i.e., ecotones) such as forest-grassland,
agriculture-native prairie, riparian and coastal zones, and
rural-urban interfaces [2-4 years].
Data sets and spatially explicit models for examining effects of
management and policy decisions on a wide range of ecosystems to
predict the efficacy and tradeoffs of management strategies at varying
scales [beyond 4 years]. A subset of these products will be developed
in collaboration with the Carbon Cycle research element.
Figure 8-6: Brightly colored waters in the Gulf of Mexico indicate
the presence of sediment, detritus, and blooms of marine plants called
phytoplankton (noted by arrow). The blooms may be caused, or enhanced, by
changes in land management "upstream" and/or changes in regional climate.
By late November, the bloom appears to have subsided. Images are
true-color Moderate Resolution Imaging Spectroradiometer (MODIS) products.
This type of remote sensing technology is essential to monitoring and
quantifying ecosystem and landscape states and changes. Source: NASA MODIS
Interagency and international facilities and mechanisms must be in
place to process, archive, and distribute the data collected and to
generate relevant products. Given the nature of global change, research
must span large spatial scales (from small experimental plots to global
satellite image mosaics, e.g., Figure 8-7), long time scales
(paleontological data from ice cores, tree rings, and fossil pollen to
near-real-time forecast models), and monitor a wide range of variables
important for characterizing the state of ecosystems. National and
international observing systems at multiple spatial scales are needed to
develop a consistent record of environmental change over time. Data from
such observing systems would provide inputs to models and allow evaluation
and improvement of model performance. The resulting large collections of
ecological and environmental data will necessitate large databases and new
approaches to data integration and analysis and will require new and
enhanced national and international partnerships.
Figure 8-7: Summer (top) and winter (bottom) composite of global
ocean chlorophyll a concentration (a surrogate for phytoplankton
biomass) and terrestrial vegetation "greenness" (a measure of potential
productivity) from September 1997 to December 2001. Some responses to
global change may be evident on extremely large spatial scales, requiring
global-level observing systems and international collaborations for
detecting and interpreting changes. When evaluated over time, composite
photographs such as this may reveal global-scale changes in the spatial
distribution, structure, and functioning of ecosystems. Source:
Project, NASA/Goddard Space Flight Center and
Future experimental and observing systems may rely on networks of
terrestrial and aquatic ecosystem observatories within particular biomes
or larger ecoregions. They should link together efficiently and build on
existing networks of field stations, experimental forests and ranges,
environmental and resource monitoring programs, and long-term ecological
research sites sponsored by many governmental and nongovernmental
organizations, some of which have lengthy records (many in
non-machine-readable forms) of ecological and environmental data.
Scientists conducting research under the Ecosystems element of the CCSP
will participate in the planning of international collaboration
activities, including those sponsored wholly or in part by the
International Geosphere -- Biosphere Programme (IGBP), such as the
Climate and Terrestrial Ecosystems (GCTE) project, the
Environmental Change and Food Systems (GECaFS) project, the
Land -- Ocean
Interactions in the Coastal Zone (LOICZ) project, the
Surface Ocean -- Lower
Atmosphere Study (SOLAS), the Global Ocean Ecosystem Dynamics (GLOBEC)
program, the Global Ecology and Oceanography of Harmful Algal Bloom
(GEOHAB) program, and the Biospheric Aspects of the Hydrological Cycle
(BAHC) project. Also important are the
Global Ocean Observing System
(GOOS), the Global Terrestrial Observing System (GTOS), the
Observing System (GCOS), the
Millennium Ecosystem Assessment, and the
International Long-Term Ecological Research (ILTER)