Effects of Wetland Presence and Upland Land Use on Wild Hymenopteran and Dipteran Pollinators in the Rainwater Basin of Nebraska, USA

Angela Begosh,Loren M. Smith,Scott T. Mcmurry,Ted G. Lagrange,Cynthia N. Park

doi:10.1007/s13157-019-01244-w

Angela Begosh, Loren M. Smith + Show 3 more

Open Access

https://doi.org/10.1007/s13157-019-01244-w

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Abstract

Pollination is an ecosystem service that is in jeopardy globally. Decreasing trends in wild pollinator populations are primarily attributed to habitat loss and degradation. These concerns are especially apparent in the Rainwater Basin of Nebraska, USA where more than 90% of the land has been cultivated and 90% of the wetlands have been lost. We compared hymenopteran and dipteran pollinator abundance, richness, and diversity in 28 wetlands and their adjacent uplands within 3 dominant land-condition types: cropped, restored, and reference state. We used vane traps to capture local pollinator insects and sweep nets to collect insect pollinators on flowers. Vane-trap captures revealed a greater abundance, richness, and diversity of hymenopteran pollinators in uplands as compared to wetlands over the entire growing season in all land-condition types. However, net collections showed that hymenopterans foraged more in wetlands than in uplands, especially in restored wetlands. The exception was September when hymenopterans were captured in uplands more than wetlands while feeding on late season forbs. Dipteran vane-trap and sweep-net captures primarily consisted of hoverflies (Syrphidae). Hoverflies were more abundant in wetlands than uplands. All pollinators used both wetlands and uplands for resources. Thus, insect-pollinator conservation can be enhanced by promoting native forb communities and pollinator habitat through wetland restoration and the planting of buffer strips.

Highlights

Global pollinator declines can jeopardize agricultural production as well as wild-plant populations and their associated biota (Potts et al 2010)
When we examined vane trap data, there were no strong patterns of differences in Hymenoptera abundance, richness and diversity among land-condition types and among playas and upland plant communities
Reference uplands had a greater abundance of hymenopterans than cropped uplands, but hymenopteran abundance in reference uplands was not statistically different from their abundance in restored uplands or playas in all land-condition types

Summary

Introduction

Global pollinator declines can jeopardize agricultural production as well as wild-plant populations and their associated biota (Potts et al 2010). There are myriad issues that contribute to pollinator declines in wild pollinator populations. Interrelated factors include pesticides, pathogens, exotic species, climate change, and habitat loss and degradation (Biesmeijer et al 2006; Winfree et al 2009; Potts et al 2010). We focus on habitat loss and degradation, which is the primary threat to native bee populations (Winfree et al 2009). Honeybee pollination is often supplementary to that of wild pollinators (Garibaldi et al 2013; Eeraerts et al 2017)

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