Premise of the study:To study pollination networks in a changing environment, we need accurate, high-throughput methods. Previous studies have shown that more highly resolved networks can be constructed by studying pollen loads taken from bees, relative to field observations. DNA metabarcoding potentially allows for faster and finer-scale taxonomic resolution of pollen compared to traditional approaches (e.g., light microscopy), but has not been applied to pollination networks.Methods:We sampled pollen from 38 bee species collected in Florida from sites differing in forest management. We isolated DNA from pollen mixtures and sequenced rbcL and ITS2 gene regions from all mixtures in a single run on the Illumina MiSeq platform. We identified species from sequence data using comprehensive rbcL and ITS2 databases.Results:We successfully built a proof-of-concept quantitative pollination network using pollen metabarcoding.Discussion:Our work underscores that pollen metabarcoding is not quantitative but that quantitative networks can be constructed based on the number of interacting individuals. Due to the frequency of contamination and false positive reads, isolation and PCR negative controls should be used in every reaction. DNA metabarcoding has advantages in efficiency and resolution over microscopic identification of pollen, and we expect that it will have broad utility for future studies of plant–pollinator interactions.

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1. Cultivation of bioenergy feedstocks is a growing land-use world-wide, yet we have a poor understanding of how bioenergy crop management practices affect biodiversity. This knowledge gap is particularly acute for candidate cellulosic bioenergy feedstocks, such as tree plantations, and for organisms that provide important ecosystem services, such as pollinators.2. We examined bee communities in 83 sites across three states in the southeastern United States-Alabama, Florida and Georgia. We compared bee abundance and diversity in 66 pine plantation sites that reflect management with and without potential bioenergy feedstock production. At least three bioenergy feedstock production methods have been proposed for this region: (a) converting conventional timber stands to short-rotation bioenergy plantations; (b) harvesting feedstock by thinning conventional plantations; and (c) harvesting of woody debris residues after plantations have been clear-cut.3. We found that bioenergy-associated management practices including younger plantations (relative to older) and woody debris removal (relative to debris unremoved) in clear-cut plantations were associated with reduced bee diversity. Removing ground debris in clear-cut plantations also drastically increased bee abundance, though this effect was largely driven by strong dominance of just two bee species.Clear-cut plantations had lower beta diversity than standing plantations. 4. Synthesis and applications. Management practices associated with bioenergy feedstock production can have negative effects on bee community diversity. In particular, harvesting of debris in clear-cut plantations dramatically reduces bee diversity. Large-scale bioenergy feedstock production that increases the prevalence of young and clear-cut stands may cause landscape-level beta diversity to decline. Nevertheless, bioenergy pine plantations likely support higher bee diversity than corn fields, an alternative bioenergy feedstock. K E Y W O R D S diversity, evenness, forestry, insect diversity, land-use change, pollinators, residue harvest | 953 Journal of Applied Ecology LOY et aL. S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section.

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