Grantee Research Project Results
2001 Progress Report: Methodologies for Extrapolating from Local to Regional Ecosystem Scales: Scaling Functions and Thresholds in Animal Responses to Landscape Pattern and Land Use
EPA Grant Number: R826764Title: Methodologies for Extrapolating from Local to Regional Ecosystem Scales: Scaling Functions and Thresholds in Animal Responses to Landscape Pattern and Land Use
Investigators: Wiens, John A. , Horne, Beatrice Van
Institution: Colorado State University
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1998 through September 30, 2001 (Extended to December 31, 2002)
Project Period Covered by this Report: October 1, 2000 through September 30, 2001
Project Amount: $581,519
RFA: Regional Scale Analysis and Assessment (1998) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Ecological Indicators/Assessment/Restoration
Objective:
This research project aims to: (1) develop ways to assess scaling of landscape patterns and organism response to landscape variation; and (2) develop predictive models that can be used to extrapolate landscape-organism linkages among scales. "Scaling" refers to the ways in which ecological patterns or processes change with changes in the spatial scale on which they are viewed. The results of this research will help to establish a methodology for extrapolating among scales of analysis or management, and for evaluating the scales at which environmental disturbances or anthropogenic stresses may have the greatest impacts on ecological systems.These objectives translate into three questions that guide this research: (1) How do we develop ways to extrapolate among scales, particularly in the face of scaling nonlinearities? (2) Can landscape measures taken over multiple scales be used to predict the scaling properties of communities or ecosystems, and thus serve as a basis for deriving extrapolation algorithms? and (3) Do different taxonomic or functional groups of organisms respond differently to broad-scale gradients in environmental or landscape features?
Progress Summary:
The research program entails three phases:
Phase 1: Preliminary Analyses and Methodology Development
To explore how landscape patterns and the distribution of organisms relate to one another, and how these relationships change with changes in scale, we evaluated three existing data sets using different methodologies. These studies indicated: (1) that the relationships and scaling of grasshopper distributions as they relate to environmental features differ when analyzed in relation to real-world space (geography) versus abstract space (ordination), and that ordination may provide greater insights; (2) that bird distributions in shrubsteppe habitats may be influenced by vegetation composition at a local scale, but by disturbance history (fire) at a broader scale, so the determinants of distribution are both multifactor and multiscale; and (3) statistical approaches based on variogram modeling can be extended to the analysis of plant community structure, to yield insights about multispecies vegetation patterns and their associations with environmental factors.
Phase 2: Gradient-based Field Studies
We are using the insights gained in the first phase of this research to structure a series of field studies that incorporate multiscale analyses of landscape patterns and features with surveys of several biological taxa (vascular plants, beetles, butterflies, and birds), which also may be analyzed at multiple scales. The basic research design involves studies at five sites located on a broad-scale precipitation/land-use gradient from the shortgrass steppe of northeastern Colorado to the tallgrass prairie of eastern Kansas. At each site, surveys are conducted on two to four 2-km-long transects that span gradients in local topography and vegetation cover, centered on grassland and riparian cover types. During the summer of 2000, information was gathered along each transect for environmental variables (soil hardness, soil pH, soil texture, near-surface temperature, and shrub coverage) and biotic variables (bird and butterfly surveys, pitfall trapping for ground-dwelling beetles and spiders, and quadrat sampling of vegetation).
We have used the information from this field sampling, coupled with remote sensing, to address several issues. Briefly, these issues focus on:
1. Scaling properties of grasslands in the central plains. Using Landsat7 spectral data and land-cover Geographic Information System (GIS) layers, we have analyzed landscape patterns across the gradient of sites. Multiscale ordination of spectral bands reveals more systematic variation among sites and is less scale-dependent, reinforcing our thesis that cross-site comparisons of spatial structure should be based on gradients rather than artificial classifications.
2. Functional groups versus taxa. We are comparing the scale-dependency of distributional responses of several taxa to landscape structure, using both traditional taxonomic criteria and functional-group classifications. Preliminary analyses of beetle data suggest that beetle functional groups differ in their responses to landscape characteristics, and in the scales on which they respond.
3. Statistical techniques. Traditional ecological analyses generally ignore spatial relationships, but as soon as one begins to consider scale effects one must also consider space. Spatial autocorrelation in the distribution of organisms may be a reflection of single-species aggregation patterns, distance-dependent interactions among species, and the spatial structure of environmental conditions. We have developed new approaches to combining geostatistical and ordination tools to assess the spatial interdependencies among these contributing factors. A manuscript describing this approach applied to plant community structure is in review, and the techniques will be applied to assess scale-dependency in the other groups we are considering.
Phase 3: Modeling and Development of Scaling Protocols
Based on the results of the first two phases, and of the continuing studies and analyses highlighted below, we will develop models that integrate landscape structure with biotic responses over multiple scales, and use these models to develop "scaling functions" that can be used to address our original goals.
Future Activities:
To better understand the effects of scaling, we will focus on alternative ways to view scale and its consequences. We will: (1) contrast categorical versus spectral (gradient) measures of landscape structure, using both remote sensing and ground-based landscape data; (2) analyze the distributional patterns of birds at multiple scales to assess the scaling of their responses to landscape structure, how this changes along the macro-gradient from shortgrass steppe to tallgrass prairie, and how functional groups versus species of birds respond; and (3) conduct field experiments to assess the responses of ground-dwelling spiders to the thermal properties of micro-landscapes, and link these results with the spider distribution-landscape patterns derived from our 2000-2001 transects sampling. Six papers produced from Phase 1 and Phase 2 studies currently are being readied for submission to scientific journals.Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 38 publications | 12 publications in selected types | All 5 journal articles |
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Type | Citation | ||
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Wiens JA. Riverine landscapes: taking landscape ecology into the water. Freshwater Biology 2002;47(4):501-515. |
R826764 (2001) R826764 (Final) |
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Supplemental Keywords:
terrestrial ecosystems, animals, indicators, scaling, habitat assessment, grazing, conservation, EMAP, Great Plains, land management, ecological effects, sensitive populations, ecosystem, terrestrial habitat, biology, ecology, modeling, monitoring, surveys, measurement methods, Geographic Information System, GIS, Landsat, remote sensing, western, central, Colorado, CO, Kansas, KS, Wyoming, WY, Idaho, ID, birds, insects, spiders, geostatistics, ordination, gradient, land use., RFA, Scientific Discipline, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Ecosystem/Assessment/Indicators, Ecosystem Protection, climate change, State, Monitoring/Modeling, Ecological Effects - Environmental Exposure & Risk, Regional/Scaling, Environmental Monitoring, Ecological Risk Assessment, Ecological Indicators, Agricultural Engineering, ecological exposure, EMAP, scaling, landscapes, risk assessment, extrapolation methods, biodiversity, ecosystem assessment, landscape context, Idaho (ID), terrestrial ecosystems, animal responses, spatial scale, New Mexico (NM), conservation, land use change, regional scale impacts, GIS, conservation , landscape patterns, grazing, indicators, land use, land management, Environmental Monitoring & Assessment ProgramProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.