Effects of restoration on the structure of plant and insect pollinator interaction networks

On-Demand

Presenting Author(s)

Elizabeth A. Lopez

University of Texas at Austin
Austin, Texas

Co-Author(s)

Sean R. Griffin

University of Texas at Austin
Austin, Texas
EL

Elinor Lichtenberg

University of North Texas
Denton, Texas
SW

Samuel Wilhelm

Austin, TX
KB

Kristen A. Baum

Oklahoma State University
Stillwater, Oklahoma
Shalene Jha

University of Texas at Austin
Austin, Texas

The interaction between plants and their insect pollinators is essential to the functioning of most terrestrial ecosystems, but can be disrupted by habitat loss and degradation. Ecological restoration is often used to support communities of plants and flower-visiting insects, but it remains unknown how these targeted efforts affect pollination networks. To understand how the structure of pollination networks can be altered by restoration, we examined the effects of prescribed burning on prairie flower communities, flower-visiting insects, and their interactions. We created a landscape-level experiment across 10 sites with four treatments based on recommendations for insect pollinator restoration from the Texas Parks and Wildlife Department: 50-acre burn, 5-acre burn, 5-acre burn with wildflower seeding, and an unburned control. We implemented the treatments, and across two summers, one before and one after, we netted insects visiting flowers and used the data to create interaction networks. We recorded 3,496 flower visits, comprising 963 unique interactions between 87 flower species and 362 insect species (of the orders Coleoptera, Diptera, Hymenoptera, and Lepidoptera). Pre-treatment networks from summer 2017 exhibited effects on structure from both local and landscape factors. Specialization marginally decreased with increased plant richness (Chisq: 3.5186, P-value: 0.06) and nestedness increased with higher proportions of nearby grassland (Chisq: 8.5533, P-value: 0.003). Within the post-treatment networks in summer 2018, we did not see any effects of plant richness, landscape, or treatment, suggesting that changes in network structure resulting from restoration may require more than a year of time post-treatment.