Plant-pollinator interactions are important for the evolution and survival of the species involved. The extinction and decline of many native species, coupled with the recent explosion of non-native species may have consequences on the fitness and survival of native Hawaiian species. To date, few studies have examined plant-pollinator interactions in Hawaii, and even fewer have compared differences in these plant-pollinator interactions across sites. Using a community-level approach, we examined the effects of elevation and succession on plant-pollinator interactions. We compared differences in pollinator visitation rates between four sites located at two elevations and two stages of succession on Mauna Loa Volcano, Hawai’i, USA. We also compared visitation rates among plant and pollinator species to see which plants and pollinators were dominant in the pollination web. To understand differences in visitation rates among plant species, we measured the correlation between plant abundance and visitation rate across all sites.
Results/Conclusions
Visitation rates differed across both elevation and succession with mid-elevation plants receiving more visits per floral unit than high elevation plants, and plants at late succession sites having a higher probability of being visited than plants at early succession sites. Plants at late succession sites were also more specialized in their pollinator usage than those in early succession sites. There was no correlation between a plant species' abundance in the community and its visitation rate. The dominant pollinators across all sites were the native yellow-faced bees, Hylaeus spp., which appear to be the most important contributors to pollination webs in the Hawaiian ecosystems we studied. In comparison to other plants across all sites, the dominant tree species, Metrosideros polymorpha, received the highest visitation rate.
