DETERMINING EFFECTIVE MITIGATION TECHNIQUES FOR VERNAL POOL WETLANDS: EFFECT OF HOST-SPECIFIC POLLINATORS ON VERNAL POOL PLANTS

In this study, we compare the diversity and quality of pollinator guilds of showy vernal pool plants in natural and created vernal pools, especially in Madera and Solano counties. Our surveys emphasize pollen host-specific andrenid bees on the assumption they are the most effective pollinators of the showy vernal pool plants. We demonstrated this for Blennosperma nanum and its principal pollinator, Andrena (Diandrena) blennospermatis in another Caltrans supported project. We find the oligolectic (pollen specific) bees in most natural relatively undisturbed vernal pool habitats, at least in the central portions of the ranges of the host plants. When created pools are constructed in areas where the bee fauna exists, they readily forage on their host plants growing in created pools. Adult andrenid bees may be held under refrigeration for at least a week. Only about 1% of adult bees exhibit evidence of reestablishing nests after release into another vernal pool habitat. We review the literature, published and unpublished on the vernal pool habitat and analyze it in relation to frequency through time, by all categories, and by faunal categories to determine the information available on the pollination process. We find only few recent references on the importance of this process to the viability of the vernal pool habitat.