The grasshopper sparrow as an indicator species in tallgrass prairies

ABSTRACT Funding constraints highlight the need for efficient approaches to manage wildlife habitat. One such approach is to monitor a single species that serves as an indicator of management effectiveness. The grasshopper sparrow ( Ammodramus savannarum ) is an obligate species of dry, upland prairie that has been proposed as a surrogate species for the Eastern Tallgrass Prairie, USA. To evaluate whether this species (or another) would make a suitable indicator for grassland birds, we examined the strength of associations in the density and occurrence of grasshopper sparrows and densities of other grassland species: sedge wren ( Cistothorus platensis ), Savannah sparrow ( Passerculus sandwichensis ), Henslow's sparrow ( A. henslowii ), dickcissel ( Spiza americana ), bobolink ( Dolichonyx oryzivorus ), and western meadowlark ( Sturnella neglecta ). No single species was a good predictor for all other species, but grasshopper sparrow density was the best predictor of the densities of other obligate upland prairie species. We also compared avian community composition between grassland sites with and without grasshopper sparrows; densities of all species except sedge wren were significantly higher at sites with grasshopper sparrows. Therefore, the grasshopper sparrow is the best choice as a single indicator species for tallgrass prairies within our study area. However, a better approach would be to select multiple, complementary indicator species to ensure that species not well‐indicated by grasshopper sparrows are adequately represented. © 2018 The Wildlife Society.