The effects of land sparing and wildlife-friendly practices on grassland bird abundance within organic farmlands

Biodiversity is often greater in organic farm systems than non-organic. However, variation in land use within organic systems limits absolute statements about its value for species conservation. Thus, a need is evident to better understand what practices associated with organic farming benefit conservation. We modeled abundance, within organic systems, of six grassland birds of conservation concern as an outcome of applied wildlife-friendly and land sparing practices at multiple spatial scales. We used a Poisson-binomial model to estimate the relative effect of abundance drivers while accounting for detectability. At the field scale, species response to vegetation structure was mixed. At a local scale, Dickcissels were more abundant at points with greater percentage of alfalfa and soybean. Three species were less abundant at points with a greater percent of local woodland and there was no significant response to local linear grass. Grasshopper Sparrows were more abundant at points with more local block grassland. At a landscape scale, Western Meadowlarks and Ring-necked Pheasants were more abundant at points with a greater percent of grassland in the landscape. Results highlight the importance of a multiscale approach and demonstrate that effective management of species should consider costs and benefits of wildlife-friendly and land sparing practices.

► Variation within organic systems limits statements about its value for conservation.
► Target species responded to farm management at multiple scales.
► The benefits of wildlife-friendly practices were limited.
► Grassland species conservation requires land spared from cultivation.