1994 LTER CROSS-SITE COMPARISONS & INTERNATIONAL RESEARCH AWARDS A 1993 ten-year review of the U.S. LTER Program recommended overall expansion to address more effectively today's long-term ecological scientific questions, develop an integrated program that will provide the basis for defensible environment decisions and policies, and implement sustainable resource management practices. The National Science Foundation has begun to implement these recommendations through special competitions to augment site research, encourage cross-site comparisons and syntheses, and expand the range of scientific disciplines to include the physical and social sciences. AWARDS--May 1994 Special Competition - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Human Modification of Landscape Function in New England and Ireland: Land Use Legacies and Atmospheric Deposition John D. Aber Harvard Forest LTER & Irish Sites Award amount: $187,500 Award duration: 36 months The forested and agricultural landscapes of New England and Europe share a common history of long-term human land use and more recent increases in anthropogenic atmospheric deposition. The commonality of interests between New England and Ireland are especially apparent. Both are regions adjacent to areas of high air pollution emissions which experience variable and episodic pollution deposition events. Both are humid regions initially covered mainly with deciduous broad-leaved forests. Both have experienced near-complete deforestation for conversion to both row-crop agriculture and grazing. A critical difference between the two is that much of New England has become reforested through farm abandonment over the last 150 years, while the Irish landscape is still dominated by agricultural use. However, recent experience demonstrating that Ireland's mild climate can support the most rapid rates of forest growth in Europe has lead to an aggressive program of reforestation, mainly with conifers native to the northwestern United States. Impacts of reforestation on landscape esthetics, land use patterns and water quality have all been questioned. Specifically, this project is designed 1) to combine existing biogeochemical datasets from the European EXMAN (EXperimental MANipulation of forest ecosystems) network with similar dataset for the northeastern United States, 2) to develop a 1-km resolution GIS for Ireland containing information on monthly average maximum and minimum temperature, monthly precipitation, monthly solar radiation and on the distribution of major soils types in order to predict potential forest productivity for Ireland using the PnET model, and to compare these results with those from a similar analysis for New England, and 3) to examine the long-term effects of land use on soil properties and function by comparing adjacent field and forest systems, adjacent forest systems with different land use histories, and forest sites with different vegetation types. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Biodiversity and Decomposition in Mesic Forests: An Across-Site Experimental Study of Biodiversity and Patterns and Processes David C. Coleman, D.A. Crossley & Bruce L. Haines Coweeta and Luquillo LTER Sites & La Selva (Costa Rica) Award amount: $199,976 Award duration: 36 months Studies of decomposition and nutrient cycling in ecosystems have been very important processes for the interpretation of ecosystem function. They have become "keystone" parameters in the LTER Program. There has been an increasing interest in the functional roles of hundreds of species of litter- and microbial- feeding fauna which occur in virtually all terrestrial sites. How do these species operate and interact, and are they "necessary" for optimal functioning of the system? This project will explore the interaction between biodiversity and decomposition processes, by studying factors causing marked differences which have been found between three moist, warm, broad-leaved forest sites, all on similar soil types. Two tropical sites, Luquillo (LUQ) in Puerto Rico, and La Selva (LAS Rica, have low and high species richness of soil microarthropods, respectively. Coweeta (CWT), in the Southern Appalachian mountains, has a species richness of microarthropods approaching that of LAS. Both CWT and LUQ are in the general substrate decomposition network study currently being conducted by Harmon, et al. The same or similar litter substrates to those of the Harmon, et al. network, will be contained in litter bags identical to the previous study. The network will be expanded to include LAS, to test the hypothesis: forests with litters containing the most diverse litter faunas will have the most rapid decomposition rates. Conversely, forests with relatively low species richness (LUQ) will have significantly lower rates of decomposition, when corrected for differences in moisture/temperature regimes. CWT is expected to have a decomposition rate intermediate to that of the two tropical sites, because of its seasonal cycles of arm wet weather. This project uses simple, proven techniques to compare decomposition rates across sites and should be the groundwork for more widespread studies of biotic interactions and processes across the LTER Network. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Investigating Controls on the Benthic Flux of Nitrogen and Phosphorus from Lake Sediments: A Comparative Hubbard Brook Ecosystems Approach Anne E. Giblin North Temperate Lakes & Arctic Tundra LTER Sites Award amount: $200,000 Award duration: 36 months This project will compare the stoichiometric relationships among benthic fluxes of oxygen, carbon, sulfur, nitrogen and phosphorous from sediments in a variety of lakes. Investigators will use a comparative ecosystem approach and a process-based diagenetic model to examine the factors which control regeneration of nitrogen and phosphorus from sediments. They will examine how the release of nitrogen and phosphorus changes in lakes across gradients of organic matter deposition, water chemistry, sediment chemistry and bottom water oxygen concentration. The data to be examined include: multi-year datasets from lakes in the Hubbard Brook, Northern Lakes and Arctic LTER sites; shorter term datasets from about 50 temperate and arctic lakes; data from several experiments where carbon inputs to the sediments and overlying water chemistry were manipulated in intact sediment cores; and data from two whole lake fertilization experiments. Investigators will use this data to generate improved conceptual and numerical models of the controls of nutrient release from freshwater sediments. These models will provide tools for the management of water quality in lakes and estuaries. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - A Climatic Analysis of Long-Term Ecological Research Sites David E. Greenland, H.J. Andrews & Niwot Ridge LTER Sites All LTER sites (including former North Inlet site Award amount: $109,353 Award duration: 18 months In this project, a comparative climatological analysis of the LTER sites will be performed which will include four items: 1. a systematic time series analysis of temperature and precipitation records of all 19 LTER sites using the same methodology for each site; 2. a compilation of projected climate change scenarios from a range of climate model experiments interpolated to LTER sites and regions and a discussion of uncertainties associated with these projections; 3. descriptions of the climate and water budget of the LTER sites; 4. a comparative analysis of the climate of all 19 sites, including analyses of regional climates for the sites. The analysis will be published as an electronic book by means of the LTER Network online information system as well as an LTER Network paper and will also be submitted for publication in peer-reviewed journals. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Comparison of Long-Term Carbon Dynamics of Two Conifer Ecosystems Mark E. Harmon, Olga N. Krankina, Arthur McKee & Warren B. Cohen H.J. Andrews LTER & Russian Site Award amount: $145,364 Award duration: 24 months Forests play a major role in the global carbon cycle, but their current role is not fully understood. To some degree, this uncertainty stems from the lack of attention to regional scale analysis. Heterogeneity between and within forested regions can significantly affect carbon cycling processes and the response to climate and landuse change. This project will compare the carbon dynamics of two significant forest regions of the globe, the Pacific Northwest and northwestern Russia at three spatial levels: stand, landscape and region. The main objective is to determine the major factors controlling the spatial and temporal patterns of carbon stores and fluxes within these two major coniferous ecosystems. This analysis will be based on the synthesis of long-term stand and weather records, forest inventory data, aerial photography, and remote sensing imagery for both regions. Past NSF-LTER/NASA studies of the Pacific Northwest forests provide the template for the proposed Russian project and comparison. The project also builds upon on ongoing collaborative study with the St. Petersburg Forest Academy. For both regions the same complex of modeling tools will be used to analyze carbon dynamics at three spatial levels as well as the impact of harvesting and carbon stored in forest projects. For northwestern Russia the models will be calibrated and tested with existing data including long-term observations on permanent plots, local growth tables and biomass equations, forest inventory data including forest types and soils, weather data, remotely sensed images and timber harvest and processing parameters. This project will encourage further international partnerships in long-term ecological studies as well as make valuable new Russian data resources available to the U.S. scientific community. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Constraints on Production and Decomposition in Temperate Semiarid Grasslands William K. Lauenroth, Ingrid C. Burke Central Plains LTER & Argentinian Site Award amount: $199,818 Award duration: 36 months Despite the considerable effort that has been devoted to understanding net primary production and decomposition in the past 30 years, there are still a number of outstanding and crucial questions for which there are not answers. The purpose of this project is to answer several of these questions for temperate grasslands. This project will comprise experimental and observational approaches to investigate the controls on aboveground net primary production, decomposition, and net nitrogen mineralization at two temperate grassland sites, one in the United and the other in Argentina. Both sites have long-term records of ecological investigations. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Cross-Site Comparisons, Syntheses and Internationalization: North Temperate Lakes & North Highland Lake District John J. Magnuson, Jonathan A. Foley, Michael S. Adams, Carl J. Bowser & Stith T. Gower Award amount: $199,460 Award duration: 36 months This project encompasses three international efforts on the long-term temporal and spatial dynamics of temperate lakes at regional to global scales. Three questions are addressed with data from widely scattered, multiple lake districts. These questions are: 1. What patterns occur in ecological variability and organization of lake ecosystems when lake districts are considered at regional and global scales? 2. Can patterns of gains and losses of species from individual lakes be related to the overall patterns of species occurrence for lakes within a region? 3. Can analyses of lake ice freeze and breakup phenologies around the globe be used to describe and understand large scale dynamics and trends in climate? The study of ecological variability and organization of lake districts will examine temporal variability patterns (coherence) of lakes within lake districts, explore the relationship between landscape position and lake variability across lakes in different lake districts, and examine relations between lake variability and factors such as lake morphometry and land use. Comparisons will provide opportunities to determine whether patterns observed at the Northern Highland Lake District occur across lake districts worldwide. The analyses of gains and losses of fish and zooplankton species will investigate regional dynamics of species gains, losses, and turnover rates in different lake districts, relate these dynamics to the extent and strength of interconnections among lakes within these regions, and investigate how human activities may influence these processes. The analyses of lake ice phenology, climate change, and variability in the Northern Hemisphere, will analyze interannual variability in thaw and freeze dates and where possible the antecedent climatic variability. Are observed patterns in Wisconsin general for larger regions of the northern hemisphere? Patterns are the recent warming based on breakup dates, and variability associated with ENSO events and interdecadal or longer time scales. Expected patterns will be generated through global climate and ice freeze modeling. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Trace Gas Cross-Site Comparison: A TRAGNET Project Dennis S. Ojima & Arvin R. Mosier LTER & Other Sites Award amount: $200,000 Award duration: 36 months This project will establish a database and model analyses to be used in determining general relationships of trace gas exchange across a broad environmental gradients in climate, atmospheric deposition of N, and soils to better quantify fluxes of these biogenic radiatively active trace gases across North America. Trace Gas Network (TRAGNET) sites will be used, an International Geosphere-Biosphere Programme/International Global Atmospheric Chemistry (IGBP/IGAC) Midlatitude Activity of a network of locations around the United States, as the core set of study sites. This network includes many LTER sites and other long-term research sites, where fluxes of C02, CH4, and N20 and possibly other trace gases are being measured and locations where trace gas model development is being conducted. Measurement of biogenic trace gas across a network of sites in North America and comprehensive analysis of these data are critical to understanding the factors controlling biogenic trace gas production and consumption. Ecosystems in this region are major contributors of these important radiatively active biogenic trace gases. Human activities modify gas fluxes both directly and indirectly. Directly, agricultural and forest management practices affect soil physical and biological properties, including those that control gas fluxes. Indirectly, air pollution and acid deposition affect fluxes and modifying biogeochemical cycles associated, especially N dynamics, with trace gas fluxes. Natural systems are both sources and sinks of trace gases, but the magnitudes of these fluxes are not know. Although trace gas flux measurements in temperate ecosystems have been made for decades, measurements have generally been infrequent (rarely extending beyond a growing season), usually small-scale, e.g., plot size treatments any may not always be comparable to other flux data collected at other sites. A coordinated analysis of biogenic trace gas flux measurements is essential to understanding these sources and sinks in a regional and global context. Three critical research needs are: (1) improved estimates of net fluxes of methane, nitrous oxide and carbon dioxide and of environmental factors which control these fluxes; (2) identification and quantification of other potentially important regions of significant fluxes, particularly those from geographic areas that have been neglected in past research; and (3) development of models to quantify how trace gas fluxes will respond to climatic, N deposition, and land management changes. The effort will bring together data from ongoing trace gas flux projects and provide the integrated database to researchers involved in the study. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Forested Ecosystems and Regional Economies: Describing, Explaining and Communicating the Relationships W. Ed. Whitelaw & Paul N. Courant Six LTER Sites Award amount: $200,000 Award duration: 36 months This project will pursue the following objectives, implementing them for six LTER sites: Descriptive objective: to develop a technically sound, but intuitively accessible, framework and language for describing and assessing the multiple relationships between a forested ecosystem and a regional economy that can be applied to different ecosystems and regional economies. Explanatory objective: to improve understanding of the factors that influence the multiple relationships between forested ecosystems and regional economies. Institutional-communicative objective: to lay the institutional foundation for (1) providing resource managers, policymakers, and the public with effective tools for describing and assessing the economic effects of changes in resource-management policy, (2) undertaking further cross-site research regarding the relationships between ecosystems and regional economies, and (3) integrating economic research with the research of other disciplines.