Uncultivated patches of land within agricultural landscapes may enhance pollination services and crop yield by providing nesting habitat and flowering resources. However, agricultural management systems may influence the quantity, quality, and distribution of these uncultivated habitat patches. Here, we (i) assessed the distribution of potential pollinator habitat at Big Sandy agricultural landscape (BSAL) and (ii) compared the landscape pattern between organically and conventionally managed farms. The BSAL is located in Montana’s Golden Triangle, an important dryland wheat producing region in the Northern Great Plains and is primarily composed of small grain producing croplands. To assess the distribution of potential pollinator habitat, we established four concentric circles of 250m, 500m, 1000m, and 2000m radii from the center of three conventional and three organic fields in 2014. We used Landsat 8 images to quantify each circle into different patch classifications (e.g., cropland, natural habitat, water, etc.) in ArcGIS. We calculated different landscape metrics including proportion, area, mean size, evenness, and diversity of each class type using V-LATE 2.0 beta (vector-based landscape analysis tools extension). We compared these metrics between conventional and organic farming systems using linear mixed models in R 3.2.0 (R Development Core Team).
Overall, BSAL is a relatively homogenous region, largely dominated by croplands with little natural habitat to sustain pollinator communities. On average, our study area was 82% cropland, which was significantly higher than any other class type (P<0.0001). Natural habitat was only about 15%. Composition of class types and their proportions were not different between the conventionally and organically managed systems (P=0.7), suggesting that they are surrounded by same amount of potential habitats for pollinators. However, class type richness was higher in organic (2.67 ± 0.33) than in conventional (1 ±0) systems in the smallest (250 m) circles (t=5, P<0.001), indicating that organic fields may favor the pollinators with shorter foraging distance. Preserving natural habitat around cropland, in addition to diversifying cropping systems and dedicating land to establish local Conservation Reserve Program (CRP) tracts may help to sustain pollinator communities in the Northern Great Plains.