While the Southern Illinois region has been found to host an impressive diversity of pollinators, this diversity is far from completely documented. Though S. Illinois is a predominantly forested region, isolated limestone glades provide excellent pollinator habitat in a natural system. The pollinator diversity of these glades is thus far unexplored. We are inventorying the pollinator communities of Cave Creek (limestone) Glade (Johnson county) and Lafarge Limestone Glade (Hardin county) nature preserves. Pollinators were collected throughout the summer of 2018, and collections will commence through the 2019 season. Floral associations observed in the field are recorded, and these data are used to construct a bipartite pollination network for each site. This allows the relative importance of different pollinator/plant species to be compared and elucidates the role of invasive species in network structure.
Results/Conclusions
2018 collections yielded 49 bee species, though identification of the diverse genus Lasioglossum is incomplete. Bees have been prioritized for analysis due to known efficacy as pollinators and high abundance (>90% of collection). The most important bee species in the network include Augochlorella aurata, Bombus griseocollis, and Halictus ligatus (all primitively eusocial species), and well as the solitary species Andrena nassonii. Important plant species include Silphium integrifolium, Helianthus divaricatus, Ratibida pinnata (all members of Asteraceae), Taenidia integerrima (Apiaceae). Two exotic legumes present at Lafarge Limestone Glade – Melilotus albus and M. officinalis – exhibited strong roles in that community’s network. A comparison of the two networks shows that Lafarge Limestone Glade, the site with higher nonnative plant richness (6 exotic species vs. 0), exhibits higher bee richness, more nestedness, more network redundancy, and a higher robustness of both bees and plants.