Pollinator Communities On Native Emergent Wetlands, Managed Emergent Wetlands, and Adjacent Croplands in the Lower Mississippi Alluvial Valley of Arkansas

Pollinator Communities On Native Emergent Wetlands, Managed Emergent Wetlands, and Adjacent Croplands in the Lower Mississippi Alluvial Valley of Arkansas

Summary

Insect pollinators supply an ecological service to crops and flowering plants by pollinating a diversity of wild plants and increasing the size and quality of harvest in agriculture production (Allen-Wardell et al. 1998; Delaplane and Mayer 2000; Fontaine et al. 2006). Despite the honeybee’s effectiveness as a pollinator for many crops, the risks associated with reliance on a single managed pollinator species have become evident over the past decades as North American honeybee populations have declined by 25% due to the parasitic mite Varroa destructor, Colony Collapse Disorder, farming intensification, habitat fragmentation, habitat loss, and agrochemicals (Steffan-Dewenter et al. 2002; Tylianakis et al. 2005; Biesmeijer et al. 2006; National Research Council 2006; vanEngelsdorp et al. 2009). Though cotton, rice, and soybeans are considered autogamy (self-pollinating), cross-breeding (via pollinators) helps increase yield, produce more viable seed, and enhance genetic diversity of the crop (Kremen et al. 2002; Pu et al. 2014).

Emergent wetlands occur adjacent to croplands throughout the Southeastern United States and create valuable floral resources for pollinators throughout the growing season. Some of these emergent wetlands on public lands are actively managed for annual plants that produce abundant seed resources for migratory waterfowl while some emergent wetlands are more passively (less frequently or less intensely) managed for perennial plants. Pollinator communities that use emergent wetlands have been poorly documented and their benefits to plant communities on surrounding lands are not fully understood.

Objectives/Performance Targets

• Compare pollinator communities between actively and passively managed emergent wetlands, and adjacent croplands,
• Assess impact of management strategies on pollinator species abundance and diversity, and
• Document whether pollinator visiting flowers in wetlands are also visiting flowers in adjacent croplands.

Accomplishments/Milestones

First, we will mention that two grants were obtained that will allow us to hire a technician next field season. We intend to survey May –September, 2016. The large number of bees collected in 2015 and the time necessary to process these samples is a concern. We plan to reduce our sampling effort per site next year; however, we would like to include more sites to get a better handle on among site variation in bee diversity. By hiring a technician next field season, we should make the change in sampling more effective and efficient. Finally, next summer, we intend to process the samples when collected.

Impacts and Contributions/Outcomes

We collected 1,746 individual bees during the 2015 field season. Species richness did not vary across the growing season in either actively or passively managed wetlands (Figs. 2, 3). Actively managed sites did not show higher total species richness than passively managed sites. These results represent half of the samples collected at each site. Cropland samples are still being processed. The data from the completion of this project will help fill the knowledge gap of bee communities in this region and that use wetlands, while also providing useful information on how land managers can promote particular floral resources that are beneficial to pollinators.