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PDF version of this section of the report PDF version of the full report The hardcopy version of this report is available free of charge from the GCRIO Online Catalog
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6. Ecosystems
The terrestrial and marine ecosystems that make up the biosphere provide critical goods and services to humanity. These include food, fiber, fuel, genetic resources, pharmaceuticals, cycling and purification of water and air, regulation of weather and climate, and natural beauty. Recent and ongoing global environmental changes�including climatic change, changes in atmospheric composition, land-use change,
habitat fragmentation, pollution, and spread of invasive species�are affecting the structure and functioning of some ecosystems, and therefore the goods and services that they provide. In turn, many ecological effects of global environmental change have the potential for feedbacks (either positive or negative) to climatic and other environmental changes. Furthermore, because many global environmental changes are expected to increase in magnitude in the coming decades, the potential exists for more significant effects on ecosystems and their goods and services. Reducing scientific uncertainties about the potential effects of global change on ecosystems, as well as the feedbacks from ecosystems to global change processes, remains a CCSP priority.
Efforts of the EIWG contribute to all five CCSP goals, with an emphasis on Goal 4 (to "understand the sensitivity and adaptability of different natural and managed ecosystems and human systems to climate and related global changes"). EIWG activities directly address questions 8.1, 8.2, and 8.3 from the CCSP Strategic Plan. Synergies and interactions exist with other CCSP research elements, including, but not limited to, the Climate Variability and Change, Global Water Cycle, Global Carbon Cycle, and Land-Use/Land-Cover Change research elements.
HIGHLIGHTS OF RECENT RESEARCHThe following are selected highlights of recent ecosystems research supported by CCSP-participating agencies.Quantifying Potential Ecosystem Feedbacks to Climatic Change.1![]() Climate Impacts Fish Recruitment by Affecting Larval Transport.2Scientists have developed a tool to predict how climate and weather affect the transport of fish larvae to their nursery areas. Fisheries biologists and physical oceanographers constructed a numerical model to predict the larval transport of an economically important flatfish, northern rock sole (Lepidopsetta polyxystra), in the southeastern Bering Sea based on their vertical position in the water column. Sustained shoreward transport during the 1980s led to a decade of above-average recruitment, and along-shelf or offshore transport in the 1990s resulted in a decade of below-average recruitment. This new model can now be used with Intergovernmental Panel on Climate Change climate projections to investigate the effects of changing climate on larval fish transport and recruitment due to changes in currents and regional wind patterns.Complex Responses of Subalpine Forests to Climatic Change.3![]()
Climatic Synchronization of Periods of Prehistoric Widespread Forest Wildfires.4The ability of climate variation to synchronize widespread forest fires across much of western North America was recently documented for a multi-century period. During the past 400 years, the El Ni�o Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) were the primary drivers of interannual to decadal variation in fire synchrony, whereas the Atlantic Multidecadal Oscillation (AMO) affected the strength of ENSO and PDO effects on wildfire synchrony at multidecadal scales. During certain phases of ENSO and PDO, fire was synchronous within broad subregions and sometimes asynchronous among those regions. In contrast, fires were most commonly synchronous across the West during warm phases of the AMO. The research is the first to demonstrate that synchrony in forest wildfires across western North America is directly related to surface conditions of the Atlantic Ocean. Current shifts to positive AMO conditions imply a potential for increased wildfire synchrony during the next few decades, in addition to that attributed to global warming.Invasive Species Patterns Track Those of Native Species.5A review of patterns of species richness (the number of species in a given area) and species density (the mean number of species per square kilometer) for both native species and non-indigenous or invasive species of plants, birds, and fishes in the continental United States and Hawaii shows that the species densities of native and non-indigenous species are positively correlated for plants, birds, and fishes. The correlations of species densities between native and non-indigenous plants and native and non-indigenous birds are especially strong (r = 0.86 and 0.93, respectively). Densities of non-indigenous plant and bird species are also highly predictable with the densities of native plant species and native bird species being by far the strongest predictive variables. These results support the hypothesis that, at least for plant and bird species, "the rich get richer," in that areas with high densities of native species tend to be more susceptible to invasion by non-indigenous species. For plant and bird taxa in the continental United States, biodiversity itself does not appear to act as a barrier to species invasions.Estimates of Tropical Pacific Ocean Productivity Lowered.6![]() Coral Reef Management Guide.7A workshop of scientists and managers, co-led by several CCSP agencies under the auspices of the U.S. Coral Reef Task Force, resulted in compilation of A Reef Manager�s Guide to Coral Bleaching. The combined research results among state/territorial, Federal, academic, nongovernmental, and international scientists concluded that warming sea surface temperatures are a key factor in mass coral bleaching events. The Guide provides managers with strategies to support the natural resilience of coral reefs in the face of climate change.Marine Pelagic Ecosystems: The West Antarctic Peninsula.8![]()
Nitrogen Limitation Constrains Sustainability of Ecosystem Response to CO2.9Using free-air CO2 enrichment technology in a prairie at the Cedar Creek Natural History Area in Minnesota, researchers in the BioCON (a long-term grassland project studying Biodiversity, CO2 and N interactions) experiment found that some of Earth�s plant life will not be able to sequester carbon from rising atmospheric CO2 levels as well as scientists once thought. Instead, soil nutrients such as nitrogen will limit plant growth even when atmospheric CO2 levels are higher. This study is the longest of its kind and consistent with other studies of trees and agricultural crops, providing evidence that nitrogen limitations may be common in the future in much of the world, despite widespread nitrogen pollution.HIGHLIGHTS OF PLANS FOR FY 2008![]() Effects of Changes in Precipitation on Southwestern Ecosystems.Climate models indicate that precipitation and soil moisture are likely to change in the southwestern United States during this century. To reduce scientific uncertainty about the potential effects of such changes on the structure and functioning of terrestrial ecosystems throughout the region, field experiments involving in situ manipulation of precipitation and soil moisture will be conducted in southwestern pinyon-juniper woodlands, coast sage, grassland, chaparral, and oak-pine forest ecosystems. Measurements will elucidate potential effects of altered precipitation on primary production processes, species diversity, decomposition of soil organic matter and related biogeochemistry, and aspects of ecological feedbacks to the physical climatic system.This activity will address Questions 4.1, 5.4, 6.4, 7.5, 8.1, 8.2, and 9.2 of the CCSP Strategic Plan. Improving Ecosystem Observations and Models.Current ecological, biogeochemical cycling, and climate models require more quantitative information on the variety, distribution, abundance, and temporal variability of terrestrial and marine groups of organisms having important physiological and ecological functions (e.g., key players in primary production, nitrogen fixers, invasive species). Planned activities for FY 2008 will focus on promoting abilities to detect attributes of these groups that can be derived through the analysis of continuous, high-resolution spectra spanning the visible, near-infrared, and shortwave infrared portions of the electromagnetic spectrum. In addition, more realistic and robust ecosystem models need to incorporate additional major drivers of ecosystem processes, especially drivers in the human system through the incorporation of socioeconomic information. Doing so will improve the realism of (1) regional and global ecological models and (2) ecological component models that link to climate, hydrological, and/or atmospheric models.This activity will address Questions 8.1, 8.2, and 8.3 of the CCSP Strategic Plan. Climate Impacts on Marine Ecosystems.![]() This activity will address Questions 8.2 and 8.3 of the CCSP Strategic Plan. Chapter References1) Torn, M.S. and J. Harte, 2006: Missing feedbacks, asymmetric uncertainties, and the under- estimation of future warming. Geophysical Research Letters, 33, L10703, doi:10.1029/2005GL025540.2) Lanksbury, J.A., J.T. Duffy-Anderson, K.L. Mier, M.S. Busby, and, P.J. Stabeno, 2007: Distribution and transport patterns of Northern rock sole, Lepidopsetta polyxystra, larvae in the southeastern Bering Sea. Progress in Oceanography, 72, 39-62. 3) Millar, C.I., J.C. King, R.D. Westfall, H.A. Alden, and D.L. Delany, 2006: Late Holocene forest dynamics, volcanism, and climate change at Whitewing Mountain and San Joaquin Ridge, Mono County, Sierra Nevada, CA, USA. Quaternary Research, 66, 273-287. 4) Kitzberger, T., P.M. Brown, E.K. Heyerdahl, T.W. Swetnam, and T.T. Veblen, 2007: Contingent Pacific-Atlantic Ocean influence on multicentury wildfire synchrony over western North America. Proceedings of the National Academy of Sciences, 104, 543-548. 5) Stohlgren, T.J., D. Barnett, C. Flather, P. Fuller, B. Peterjohn, J. Kartesz, and L.L. Master, 2006: Species richness and patterns of invasion in plants, birds, and fishes in the United States. Biological Invasions, 8, 427-447. 6) Behrenfeld, M.J., K. Worthington, R.M. Sherrell, F.P. Chavez, P. Strutton, M. McPhaden, and D.M. Shea, 2006: Controls on tropical Pacific Ocean productivity revealed through nutrient stress diagnostics. Nature, 442, 1025-1028. 7) Marshall, P.A. and H.Z. Schuttenberg, 2006: A Reef Manager�s Guide to Coral Bleaching. Great Barrier Reef Marine Park Authority, Townsville, Australia. 8) Ducklow, H.W., K. Baker, D.G. Martinson, L.B. Quetin, R.M. Ross, R.C. Smith, S.E. Stammerjohn, M. Vernet, and W. Fraser, 2006. Marine pelagic ecosystems: the West Antarctic Peninsula. Philosophical Transactions of the Royal Society B, 362, 67-94. 9) Reich, P.B., S.E. Hobbie, T. Lee, D.S. Ellsworth, J.B. West, D. Tilman, J.M.H. Knops, S. Naeem, and J. Trost, 2006. Nitrogen limitation constrains sustainability of ecosystem response to CO2. Nature, 440, 922-925.
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