Identifying opportunities for conservation embedded in cropland anthromes

Anthromes characterize terrestrial ecological patterns in terms of human populations and how these populations use the land. However, data are needed to assess the conservation value of habitats embedded in anthromes, particularly when possible conservation opportunities do not reflect the traditional focus of conservation in a region. One such region is the central Great Plains of North America where the grassland biome has been replaced by a cropland anthrome with a landscape mosaic dominated by arable crops with small patches of grass and woody cover embedded within. Grassland birds have been the primary focus of avian conservation research and practice, a reflection of the biome classification. Yet conservation of other bird species may be a missed conservation opportunity better identified via anthromes. In this project we evaluated the variation in abundance of shrubland and open forest birds in response to heterogeneity and availability of woody and grass cover at local (100 m) and landscape (5,000 m) scales. We found that local heterogeneity, a trait of croplands not grasslands, was the best predictor of abundance, with five species of conservation concern more abundant in heterogeneous sites. There was limited response to woody cover and a mixed response across scale to grassland cover with local response positive and landscape negative. These data suggest that increasing heterogeneity in the Great Plains cropland anthrome may provide a unique conservation opportunity. In particular, farm systems have the capacity to complement regional species conservation efforts by increasing heterogeneity. Importantly these conservation efforts may not come at the expense of grassland bird conservation or crop production. The limited response to extensive grassland cover at the larger scale suggests that in Great Plains agroecosystems, a diverse mix of crops, pasture, and linear habitats would allow farmers to continue to produce food while contributing to the conservation of species of concern.