Multi-scale effects of habitat loss and fragmentation on lesser prairie-chicken populations of the US Southern Great Plains

Abstract

Large-scale patterns of land use and fragmentation have been associatedwith the decline of many imperiled wildlife populations. Lesserprairie-chickens(Tympanuchus pallidicinctus) are restricted to thesouthernGreat Plains of North America, and their population and range have declined by> 90% over the past 100 years. Our objective was to examine scale-dependentrelationships between landscape structure and change and long-term populationtrends for lesser prairie-chicken populations in the southern Great Plains. Weused a geographic information system (GIS) to quantify landscape composition,pattern and change at multiple scales (extents) for fragmented agriculturallandscapes surrounding 10 lesser prairie-chicken leks. Trend analysis oflong-term population data was used to classify each population and landscape(declined, sustained). We analyzed metrics of landscape structure and changeusing a repeated measures analysis of variance to determine significant effects(α = 0.10) between declining and sustained landscapes across multiplescales. Four metrics of landscape structure and change (landscape change index,percent cropland, increases in tree-dominated cover types, and changes in edgedensity) contained significant interactions between population status andscale,indicating different scaling effects on landscapes with declining and stablepopulations. Any single spatial scale that was evaluated would not have givencomplete results of the influences of landscape structure and change on lesserprairie-chicken populations. The smallest spatial scales (452, 905, and 1,810ha) predicted that changes in edge density and largest patch sizewere the only important variables, while large-scale analysis (7,238ha) suggested that the amount of cropland, increase in trees(mostly Juniperus virginiana), and general landscapechanges were most important. Changes in landscape structure over the pastseveral decades had stronger relationships with dynamics of lesserprairie-chicken populations than current landscape structure. Observed changessuggest that these local populations may be appropriately viewed from ametapopulation perspective and future conservation efforts should evaluateeffects of fragmentation on dispersal, colonization, and extinction patterns.