@inbook {JRN52666, title = {Cross-site comparisons of precipitation and surface water chemistry}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {46-50}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {6}, address = {Springfield, Virginia}, abstract = {

Measurements of pools and fluxes of transport or cycling of elements and compounds through the biotic and abiotic components provide critical information about the function of ecosystems. Because the time for a molecule to be completely transported through an ecosystem may be decades to millennia, long-term data provide one of the few means to estimate how ecosystems use and respond to changes in inputs of nutrients and toxic substances. This chapter tests two hypotheses related to patterns in biogeochemistry across sites: (1) patterns in atmospheric deposition over the past 20 years are different for the eastern and western parts of the U.S., and (2) changes in atmospheric deposition are related to changes in human population density for some sites. Long-term data, collected at multiple sites across the US, in chemical measurements in wet deposition, e.g., sulfur dioxide, nitrogen oxide, and ammonia emission data, and in human population size support both hypotheses.\  The results illustrate that the effects of human activities on biogeochemistry vary regionally and across the continent, and demonstrate that cross-site comparisons of long-term data can provide new insights into the spatial patterns of transport and cycling of elements and compounds.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-6.pdf}, author = {Charles T. Driscoll and Peter M. Groffman and John M Blair and Ariel E. Lugo and C. Laney and Debra C. Peters} } @inbook {JRN52673, title = {Management and policy implications of cross-and within-site, long-term studies}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {206-215}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {15}, address = {Springfield, Virginia}, abstract = {

This chapter explains the implications long-term data bring to natural resource management and policy-making.\  It first explains the two perspectives of long-term data, then explains the values brought by the two perspectives to natural resource management.\  The two perspectives are retrospective and predictive:\  long-term data enable us to examine data retrospectively to identify temporal and spatial sensitivities, and to build these historical perspectives into predictive models where we can objectively evaluate potential future scenarios. The values are as follows.\  First, with the understandings gained by retrospectively examining the long-term data, the managers can develop data-based guidelines to direct the appropriate timing and application of management practices.\  Second, long term data provide the opportunity to evaluate policies and programs that have been implemented for resource conservation.\  The ability to evaluate environmental responses following policy implementation provides the data necessary to validate policies or may lead to their subsequent revision.\  Third, long term data collection provides the opportunity for clients, partners, and stakeholders to be engaged in scientific processes. These interactions create opportunities, not only for technology and information transfers, but for users to inform the science and its research directions.\  Fourth, the predictive models built based on long-term data can be used to estimate the effects of a variety of climatic and management scenarios and are critical to informed decision-making and effective communication between natural resource managers and policy makers.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-15.pdf}, author = {Kris Havstad and Joel R. Brown} } @inbook {JRN52665, title = {Patterns of net primary production across sites}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {42-45}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {5}, address = {Springfield, Virginia}, abstract = {

Net primary production (NPP) is a fundamentally important and commonly measured ecosystem process that provides an integrative estimate of energy capture and flow into systems, and consequently the energy available for use by other trophic levels. A wide range of productivity levels occurs globally with high temporal dynamics among sites. This chapter discusses approaches to estimating NPP, highlights site-specific trends in productivity, and provides examples of past synthetic analyses across space and time. In terrestrial ecosystems, aboveground NPP are commonly measured or estimated. In many sites, spatial variation in NPP among locations within a site can overwhelm temporal variation.\  In terms temporal patterns, at some sites clear temporal trends exist: NPP either increases or decreases with time; at other sites, strong interannual variations exist.\  Past synthetic analyses have provided key insights into the relative roles of biotic versus abiotic drivers of dynamics as well as elucidating where and when biogeochemical versus climatic factors underlie patterns of NPP across biomes.\  The chapter proposes four questions that can be addressed as long-term data sets at more sites become available.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-5.pdf}, author = {A. K. Knapp and M. D. Smith and Debra C. Peters and S.L. Collins} } @inbook {JRN52663, title = {History and organization of the EcoTrends project}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {21-27}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {2}, address = {Springfield, Virginia}, abstract = {

This chapter describes the internal organization and timeline of the EcoTrends Project, from which the data and recommendations in the subsequent chapters are generated.\  The project began in 2004, and its organizational structure expanded over the next six years to include many activities and dozens of individuals from six major groups.\  The six major groups are the EcoTrends Project Office, the EcoTrends Editorial Committee, the EcoTrends Technical Committee, participating site scientists, information managers, and technical staff, the Long Term Ecological Research Network Office, and the EcoTrends Socioeconomic Working Group.\  The major activities occurred from 2004 to 2010, when this book is completed, are listed in the chapter.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-2.pdf}, author = {C. Laney and Debra C. Peters and Baker, K. S.} } @inbook {JRN52674, title = {Recommendations for data accessibility}, year = {2013}, pages = {216-225}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {16}, address = {Springfield, Virginia}, abstract = {

The EcoTrends project has generated hundreds of standardized, documented datasets from many sites and scientific fields.\  During the process of generating data comparable between many sites and across several organizational networks, novel solutions to technical, organizational, and communication challenges have been created.\  This chapter presents ten recommendations for site-level information management and for future synthesis projects.\  The recommendations are related to three broad categories: (1) data management and products, (2) project design, and (3) information environments to support synthesis projects. For each recommendation, the chapter provides specific examples of the challenges that EcoTrends faced, the lessons learned, and then explains the recommendation that may help address the challenge in future projects.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-16.pdf}, author = {C. Laney and Baker, K. S. and Debra C. Peters and Ken Ramsey} } @inbook {JRN52664, title = {Cross-site comparisons of state-change dynamics}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {36-41}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {4}, address = {Springfield, Virginia}, abstract = {

Changes in the state of a system, for example from grasslands to shrublands or from dominance by one fish species to another species, with associated changes in other parts of the system, are often irreversible. Most of these state changes bring forth negative impacts on ecosystem, resulting in altered levels of biodiversity, rates of nutrient cycling, changes in air and water quality, and increased losses of soil and nutrients by wind and water erosion.\  This chapter illustrated six examples of state changes in various types of ecosystems: vegetation state changes in deserts, penguin dynamics in Antarctica, fish dynamics in Wisconsin lakes, plankton dynamics in the Pacific Ocean, subtidal dynamics off Pacific Coast, and shifts in coastal fish assemblages in the Pacific Ocean.\  These examples clearly show the impact of global environmental change (warming, invasive species, altered trophic structure) on the abundance and distribution of dominant and subordinate species in aquatic, marine, and terrestrial systems. Because this era of rapid environmental change is only beginning to be manifest in species responses, long-term data will continue to be needed to quantify and predict the non-linear system responses that are likely to occur in the future.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-4.pdf}, author = {Debra C. Peters and William R. Fraser and T. K. Kratz and Mark D. Ohman and Andrew Rassweiler and Sally J. Holbrook and Russell J. Schmitt} } @inbook {JRN52667, title = {Disturbance regimes and ecological responses across sites}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {58-71}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {9}, address = {Springfield, Virginia}, abstract = {

Disturbances affect ecosystems in almost limitless ways. The effects of disturbances extend beyond the initial impacts that are usually visible to the human eye. Therefore, for many disturbances long-term data are needed to unravel their effects.\  This chapter first presents characteristics of disturbances for each of four major classes of disturbance: climatic, physical, biotic, and anthropogenic.\  It then discusses ecosystem responses by disturbance class.\  For climatic disturbances, ecosystem responses to hurricanes, drought, and global warming are discussed; for physical disturbances, wildfire on land and wave height in ocean; for biotic disturbance, herbivores feeding on lower tropic levels, invasive species, and a plant disease; for anthropogenic disturbance, changes in land use patterns.\  These long-term records of ecosystem responses to disturbance illustrate the complexity of disturbance effects. Ecosystem responses are influenced by multiple disturbances and interactions with other factors, which make it very difficult to attribute cause and effect. Clearly large-scale, multiple-site experiments are needed to further unravel the relationships between particular disturbance events and ecosystem responses.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-9.pdf}, author = {Debra C. Peters and Ariel E. Lugo and F.S. Chapin III and Tepley, A. J. and F. J. Swanson} } @inbook {JRN52675, title = {Long-term research across sites, ecosystems, and disciplines: synthesis and research needs}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {226-233}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {17}, address = {Springfield, Virginia}, abstract = {

The EcoTrends Project is one of the first attempts to standardize, simplify, integrate, and visualize data from diverse terrestrial, aquatic, and marine ecosystems to promote understanding and synthesis by a broad audience. This chapter discusses key scientific results from this project, describes developing conceptual and operational frameworks for cross-site synthesis, and provides recommendations for future research. Key results are: mean air temperature has increased at 24 sites, and annual precipitation has increased at 9 sites with no obvious spatial distribution in either climate variable. Trends in atmospheric chemistry show clear patterns across the continent with reduced deposition of nitrate and sulfate in precipitation through time in the eastern U.S. compared with the West. Patterns in stream water chemistry across sites do not reflect broad-scale patterns in atmospheric chemistry; thus local conditions have strong influences on chemical inputs to and losses from streams. Human population density has increased at all sites, although at different rates. Biotic data are often idiosyncratic in that they reflect high spatial and temporal variability inherent in biological phenomenon.\  It is proposed that cross-site synthesis studies should integrate three aspects of ecological research: depth (individual sites being studied in great detail), length (data being collected over long periods), and breadth (phenomena being studied across broad spatial extents).\  The strongest recommendation for future research is to make data and associated metadata easily accessible to and usable by others.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-17.pdf}, author = {Debra C. Peters} } @inbook {JRN52669, title = {Long-term trends in climate and climate-related drivers}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {81-114}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {11}, address = {Springfield, Virginia}, abstract = {

This chapter shows long-term data and trends in climate and climate-related drivers for each site.\  It contains a brief introduction to the topic, and methods of measurements, selection of variables, and their data source. It consists primarily of a large number of figures showing long-term data for different variables.\  On land, air temperature (mean, minimum, and maximum), precipitation, Palmer Drought Severity Index, and Walter-Lieth climate diagrams are selected.\  In water, streamflow, sea level, ice duration, water clarity, and water temperature are selected.\  Two types of graphs are included to show trends in the variables and to provide a sense of change across a range of spatial scales (continent, site) for each variable: maps at continental scale showing either the mean across years or the slope of the regression line (if significant) across time, and site-scale data through time.\  Air temperatures are increasing in at least one variable (minimum, mean, maximum) for 27 of the 50 sites.\  Sea level is increasing at all 11 coastal sites.\  Observing these trends in climate across multiple ecosystems across continents is only possible with spatially extensive, long-term data collection and analysis, such as provided by the EcoTrends Project.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-11.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman} } @book {JRN52662, title = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {378}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, address = {Springfield, Virginia}, abstract = {

The Eco Trends Editorial Committee sorted through vast amounts of historical and ongoing data from 50 ecological sites in the continental United States including Alaska, several islands, and Antarctica to present in a logical format the variables commonly collected.\  This report presents a subset of data and variables from these sites and illustrates through detailed examples the value of comparing long-term data from different ecosystem types. This work provides cross-site comparisons of ecological responses to global change drivers, as well as long-term trends in global change drivers and responses at site and continetal scales.\  Site descriptions and detailed data also are provided in the appendix sections.

\⇒ This book is available for download (PDF format) below

\⇒ Available from http://www.ars.usda.gov/is/np/indexpubs.html

\⇒ Copies may be purchased in various formats (microfiche, photocopy, CD, print on demand) from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161, 800-553-6847, www.ntis.gov

Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change\  (download PDF - 313 MB)

Download the book in PDF in it\&$\#$39;s entirety (above) or by section (below)

Contents

Introduction to Cross-Site Comparisons and History and Organization of the EcoTrends Project\  (8.29 MB)

Cross-Site Comparisons of Ecological Responses to Global Change Drivers\  (21.8 MB)


Long-Term Trends in Global Change Drivers and Responses at Site and Continental Scales\  (197 MB)


Appendices \& Index\  (79 MB)

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029 Bk.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman and R. B. Waide and Jin Yao} } @inbook {JRN52676, title = {Long-term trends in ecological systems: An introduction to cross-site comparisons and relevance to global change studies}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {1-20}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {1}, address = {Springfield, Virginia}, abstract = {

This chapter explains the importance of long-term data to ecological studies and the needs of creating a way to provide accessible and comparable multi-site long-term data. The Earth{\textquoteright}s environment is changing in many ways at local, regional, and global scales. Dramatic changes have occurred in climate, land cover, and habitat availability over the past several centuries. Long-term data (\> 10 years) are needed to assess the rate and direction of change, to distinguish directional trends in these changes (e.g., persistent increases or decreases) from short-term variability (e.g., multi-year cycles), and to forecast environmental conditions in the future.\  It also sets up the stage for the rest of the chapters in the book, presenting the purposes, audience and practical applications of the book, explaining how the study sites, variables, and data sets are selected, and how the data are presented and analyzed, and laying out the organization of the book.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-1.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman and R. B. Waide and Jin Yao} } @inbook {JRN52671, title = {Long-term trends in human demography and economy across sites}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {162-190}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {13}, address = {Springfield, Virginia}, abstract = {

This chapter shows long-term data and trends in human demography and economy for each site.\  It contains a brief introduction to the topic, and methods of measurements, selection of variables, and their data source. It consists primarily of a large number of figures showing long-term data for different variables.\  Total population, the percentage of the population living in urban areas, and the density of people in the counties associated with each site are selected.\  Four economic variables fore each focal county of a site are also selected: the percentage of the population employed by one of four economic sectors: commercial industries, farming, manufacturing, and service industries.\  Two types of graphs are included to show change through time across a range of spatial scale for each variable: maps of continental scale showing either the \% change in total population for four time periods (1800 to 1850; 1850 to 1900, 1900 to 1950, 1950 to 2000) or the \% of the population that was urban in each of four time periods (1850, 1900, 1950, 2000); and maps and graphs showing site-scale data through time. The settlement of the country occurred from the east coast and then to the west coast by 1900, and then to the interior between 1900 and 1950. Losses of population in the Midwest occurred between 1950 and 2000. Most areas of the country had a high percentage of urban population by 1950. Urbanization continued for most of the country until 2000 with the Northeast, Appalachian Mountains, and northern Wisconsin providing notable exceptions.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-13.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman} } @inbook {JRN52670, title = {Long-term trends in precipitation and surface water chemistry}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {115-161}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {12}, address = {Springfield, Virginia}, abstract = {

This chapter shows long-term data and trends in precipitation and surface water chemistry for each site.\  It contains a brief introduction to the topic, and methods of measurements, selection of variables, and their data source. It consists primarily of a large number of figures showing long-term data for different variables.\  Volume-weighted concentration (mg/L) and area-based wet deposition (kg/ha) from precipitation, and concentration in surface water (mg/L) of nitrogen (as nitrate and ammonium), sulfur (as sulfate), chloride, and calcium are selected.\  Two types of graphs are included to show trends in the variables and to provide a sense of change across a range of spatial scales (continent, site) for each variable: maps at continental scale showing either the mean across years or the slope of the regression line (if significant) across time, and site-scale data through time.\  Nitrate and sulfate deposition are decreasing in many Eastern sites, consistent with efforts to control emissions of acid-causing nitrogen and sulfur from power plants in this part of the country.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-12.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman} } @inbook {JRN52672, title = {Long-term trends in production, abundance, and richness of plants and animals}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {191-205}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {14}, address = {Springfield, Virginia}, abstract = {

This chapter shows long-term data and trends in production, abundance, and richness of plants and animals for each site.\  It contains a brief introduction to the topic, and methods of measurements, selection of variables, and their data source. It consists primarily of a large number of figures showing long-term data for different variables.\  Net primary production, plant biomass and species richness, animal abundance and species richness are selected.\  Figure of site-scale data through time of each variable is shown, and a regression line is shown if the relationship is significant and the trend appears linear.\  The site graphs are shown on a continental map with similar sites to allow comparison among sites.\  At many sites, multiple locations are sampled for plant and animal dynamics. The large within-site variability in responses often overwhelms trends through time.\  Although plant response variables of ANPP, richness, and biomass are sampled for most sites to allow cross-site comparisons, animal response variables are more variable among sites with fewer comparable groups. These results indicate that each site selects representative trophic groups from the local ecosystems, instead of attempting to standardize across sites.\  The length of the time series also varies across sites which further complicates cross-site comparisons.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-14.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman} } @inbook {JRN52668, title = {Cross-site studies "by design:" Experiments and observations that provide new insights}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {72-80}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {10}, address = {Springfield, Virginia}, abstract = {

The cross-site comparisons presented in the previous chapters are all conducted after the individual studies are completed.\  The differences in experimental design in individual studies in a posteriori cross-site studies limit the scope of questions that can be addressed, and the powerfulness and confidence in the conclusions.\  This chapter describes cross-site studies that are {\textquotedblleft}by design{\textquotedblright} where the questions, experimental layout, methods, and measurements included multiple sites from the beginning. These a priori cross-site studies provide powerful tools to understand the phenomenon of global change and to predict its impacts on ecosystems and society. Two types of a priori cross-site studies are described: (1) experimental manipulations of drivers or system properties, and (2) observations or monitoring of natural or managed ecosystems located along environmental gradients. Within each type, examples of both on-going or completed experiments and new or developing experiments are presented.\  For each example, insights that would not have been obtained with other approaches are also presented. The limitations and difficulties of this type of studies are listed.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-10.pdf}, author = {Jin Yao and O. E. Sala and Debra C. Peters} }