Cows and Plows: Science-based Conservation for Grassland Songbirds in Agricultural Landscapes

Temperate grasslands are among earth’s most imperiled ecosystems. In North America, steep declines of endemic songbird populations indicate that grassland loss and degradation may be approaching critical levels. Grasslands are agricultural landscapes largely (~85%) under private ownership with little formal protection status. Remaining bird populations depend on grazing lands that have not been converted to cropland. We combine regional data from a hotspot for grassland bird diversity (northeast Montana, USA; 26,500-km2) with continental data spanning the northern Great Plains (1,000,000-km2) to evaluate how land use and management influence bird distribution and abundance. Regionally, habitat used by seven grassland specialists spanned a gradient of sparse to dense herbaceous cover. Livestock grazing influenced cover and birds but its effect was highly dependent on precipitation and soil productivity. Species distributions were variable across relatively broad spatial scales and only large landscapes (≥ 1,492-km2) were sufficient to capture maximum diversity and stability in community composition. At this scale, more grassland habitat and a wider range in herbaceous cover values were associated with high bird diversity. Sprague’s Pipit (Anthus spragueii), Baird’s Sparrow (Ammodramus bairdii), Chestnut-collared (Calcarius ornatus) and McCown’s (Rhynchophanes mccownii) longspurs were particularly sensitive to habitat amount and had reduced densities in grass-poor landscapes despite local conditions. Continentally, the breeding range of Sprague’s Pipit was restricted to areas with a high proportion of continuous grassland and a relatively cool, moist climate. Most of the pipit population (70%) relied on private lands and a quarter occurred in habitat at risk of future tillage. Spatially hierarchical models placing response to local habitat within its landscape context revealed that broad-scale patterns in land use and grassland productivity constrained the continental distribution of pipits and Chestnut-collared Longspur. Findings suggest that maintenance of large and intact grassland landscapes should be a top conservation priority. Remaining populations rely on private land, emphasizing the importance of voluntary approaches that incentivize good stewardship. Accounting for interactions between climate, soils and livestock within existing grassland landscapes may enable managers to maintain high bird diversity

Species-Specific Scaling to Define and Conserve the Northern Great Plains Region

Prairie ecosystems are in a continuous state of flux, shifting by processes that include variable weather patterns and climatic conditions, disturbance regimes, and more recently, human-induced modification. Similarly, wildlife resources fluctuate across the landscape as a result of these ever-changing conditions; however, human alterations have increased, removed, and manipulated the ecological processes of the prairie. Specifically, the spatial scales at which humans manage and interact with the landscape are often inconsistent or incompatible with the scales required for the persistence of wildlife populations. Our synthesis demonstrates how the spatial scales at which wildlife in the Northern Great Plains of North America operate have been constrained by human intervention. This process of anthropogenic scaling has affected the decline of many native wildlife populations and in some cases has resulted in the complete extirpation of species from the landscape. We use historical observations and recent quantitative data to describe the primary cause of spatial scale alteration for prairie focal species (i.e. plains bison, pronghorn, grassland birds, Greater Sage-grouse, black-tailed prairie dogs, swift fox, prairie rattlesnakes) using migration, home range, distribution, and dispersal distances as metrics. We then describe the role that spatial scale plays in wildlife management of the prairie landscape from the non-profit, state, and federal perspective and how these entities are managing at the scales of each focal species