Value of wildland habitat for supplying pollination services to Californian agriculture

Rangelands can provide an important ecosystem service to adjacent agricultural fields by providing foraging and nesting habitat that supports populations of naturally occurring crop pollinators, chiefly bee species. Rangeland habitats such as grasslands, meadows, savannah,and shrublands support diverse bee communities due to the wide variety of nesting habitats they supply. Such habitats include undisturbed ground, cavities in the ground and trees, and hollow-stemmed grasses and reeds that are suitable for species of ground-nesting, wood- and cavity-nesting, and stem-nesting bees, respectively. Similarly, rangeland habitats often provide a diverse array of flowering forbs, shrubs, and trees that furnish successive blooms, supporting the needs of multiple bee species across their flight seasons. These bee populations and communities are then available to provide crop pollination in adjacent agricultural fields. Our paper outlines a method for quantifying the value of pollination services supplied by wild bee communities based on the area of nearby wildland habitats, chiefly rangelands, to pollinator-dependent crops in California, one of the largest agricultural economies in the world.