Cost, risk, landscape context, and potential treatments vary with biological value for conservation of declining grassland birds

Abstract

Spatially explicit models are an important component of systematic conservation planning, enabling the depiction of biodiversity metrics across landscapes and objective evaluation of candidate sites for conservation delivery. However, sites considered “best” for conservation are typically viewed from the standpoint of biological value and may not be the most effective or efficient when risk of habitat loss, cost of conservation, intended conservation treatments, and overall conservation strategy are considered. We evaluated risk of habitat loss, land cost, and landscape context for geographic areas harboring most-dense to least-dense population quartiles for 16 species of grassland birds in the US northern Great Plains. Differences in land cost, risk of grassland conversion, and landscape context among quartiles and species indicated that a minimum-area strategy may be inefficient and even ineffective. Priority zones for western species were generally associated with lower agricultural land cost, more protected land, and landscape characteristics associated with intact grasslands; eastern species were generally associated with higher agricultural land cost, tillage probability, grass loss, cropland, development, forest, Conservation Reserve Program grasslands, and distance to grass. Our results indicate that addressing areas outside of population cores increases conservation options and may provide substantial benefits to portions of populations that are most vulnerable to habitat loss or other stressors.