Pollinator resource use in rangelands managed with patch burn grazing

Pollinators of the North American Great Plains evolved with a heterogeneous mosaic of spatially and temporally shifting vegetative patches created by different fire and grazing interactions. This vegetative habitat heterogeneity provides fundamental pollinator resources – feeding, breeding, and nesting sites – that often occur in dissimilar habitat types across the landscape. The Flint Hills ecoregion contains more than 80% of all remaining native tallgrass prairie in North America, yet the rangelands that cover more than 90% of this ecoregion are managed for uniformity in vegetative structure and plant species composition. This uniformity rarely provides all pollinator resource needs, or corridors that allow them to search for resources in adjacent areas. Pollinators are fundamental to cattle and crop gains, as well as ecosystem stability, and their decline in the Great Plains is partially due to current rangeland management practices. Patch-burn grazing (PBG) is a rangeland management technique that has been shown to introduce habitat heterogeneity into rangelands while maintaining cattle weight gains. We assessed the conservation value of PBG to increase pollinator diversity and abundance in working rangelands. Results from pollinator surveys showed a significant increase in pollinator diversity and abundance in PBG (Ps<0.05), as well as significant spatial and temporal shifts in community composition (Ps<0.05) as compared to traditionally managed pastures. Moreover, three grass skippers on the Kansas List of Species of Greatest Conservation Need were found only in PBG pastures. Future research will examine bumblebee and regal fritillary space-use in PBG using radio transmitters, and include mark-recapture studies on regal fritillaries.