Plant-pollinator networks and arthropod communities in fire-maintained sandhills
The majority of vertebrate wildlife consume insects during some or all of their seasonal and life cycles, because these invertebrates are reliable sources of protein, fat, vitamins, and minerals. Additionally, insects perform numerous important ecosystem functions that support both plant and animal populations, including pollination, nutritional conversion (from plant material into more nutritious animal protein), and seed dispersal. The insect fauna of longleaf pine sandhills has been conservatively estimated at 4,000 to 5,000 species. This diversity virtually guarantees that insects play numerous and complex roles in sandhill food webs, but little is known about sandhill insect communities and how they are affected by prescribed fire regimes and land management activities that are primarily designed to benefit vertebrate wildlife.
In order to assess the relationships of insect and pollinator communities to fire and vegetation management, it is necessary to sort out anthropogenic sources of variation from natural environmental gradients, which will enable us to identify areas in which management can influence species diversity and plant-pollinator networks. The study sites have been chosen carefully in order to provide adequate replication of a variety of environmental variables (soil moisture, soil texture, and elevation) and standardize others (time-since-fire), to facilitate the most accurate analysis possible of the management-related causes of variation (vegetation structure and prescribed fire regime) in plant-pollinator network structure and insect species diversity. On each of 9 sandhill preserves in North-Central Florida, we are trapping insects and observing plant-pollinator interactions on a monthly basis, in conjunction with the collection of vegetation and environmental data. The results of this study will help fill two major data gaps regarding the insect fauna of longleaf pine sandhills: 1) data on sandhill insect communities and their relationships to fire-managed plant communities; and 2) data on plant-pollinator networks in sandhills and their relationships to fire management.