DOI: 10.5061/dryad.j0zpc86n6
title: Spatiotemporal patterns of forest pollinator diversity across the southeastern United States

description: Efforts to understand how pollinating insect diversity is distributed
 across large geographic areas are rare despite the importance of such work
 for conserving regional diversity. We sought to relate the diversity of
 bees (Hymenoptera: Apoidea), hoverflies (Diptera: Syrphidae), and
 butterflies (Lepidoptera) to the ecoregion, landscape context, canopy
 openness, and forest composition across southeastern U.S.
 forests. We established 5-7 plots in each experimental forest. In
 each, we sampled pollinators monthly (March-September) using colored pan
 traps, and collected data on local forest characteristics. We used the
 National Land Cover Database (NLCD) to quantify surrounding land cover at
 different spatial scales. Bee richness was negatively correlated with both
 the amount of conifer forest and the extent of wetlands in the surrounding
 landscape but was positively correlated with canopy openness. Hoverflies
 and butterflies were less sensitive to landscape context and stand
 conditions. Pollinator communities differed considerably among ecoregions,
 with those of the Central Appalachian and Coastal Plain ecoregions being
 particularly distinct. Bee richness and abundance peaked two months
 earlier in Central Appalachia than in the Coastal Plain and Southeastern
 Mixed Forest ecoregions. Our findings reveal ecoregional differences in
 pollinator communities across the southeastern U.S. and highlight the
 importance of landscape context and local forest conditions to this
 diverse fauna. The closed broadleaf forests of Appalachia and the open
 conifer-dominated forests of the Coastal Plain support particularly
 distinct pollinator communities with contrasting seasonality. Our results
 suggest pine forests may reduce pollinator diversity in regions
 historically dominated by broadleaf forests. However, efforts to create
 more open canopies can help improve conditions for pollinators in planted
 pine forests. Research exploring associations between forest pollinators
 and different broadleaf tree taxa is needed to better anticipate how they
 will be impacted by various management activities.
description: Pollinators (bees, butterflies, and hoverflies) were sampled
 using colored pan traps at 97 locations in 19 experimental forests across
 the southeastern United States. Data on canopy openness, tree composition,
 and basal area were collected at each plot. Landscape variables such as
 the amount of conifer forests and wetlands were based on National Land
 Cover Database data. This data file includes the five datasets that are
 used in the analysis. The "combined_matrix" includes
 species-level abundances by plot and was used in the community analysis
 (NMDS, adonis2, indicator species analysis). The file
 "merged_data_for_analysis" includes landscape and stand metrics
 as well as the richness of each pollinator taxa used in the diversity
 modeling. The last three datasets show the incidence of species by
 pollinator group used in the iNext analysis to compare gamma diversity
 among the three most-sampled ecoregions.
description: # Spatiotemporal patterns of forest pollinator diversity across the
 southeastern United States
 [https://doi.org/10.5061/dryad.j0zpc86n6](https://doi.org/10.5061/dryad.j0zpc86n6) There are five data files provided used in the analysis. 1\) The file "combined_matrix" includes species-level abundances by plot and was used in the community analysis (NMDS, adonis2, indicator species analysis). Column names that may not be obvious include: * location: the plot name (experimentalforest_uniquenumber) * ecoregion: the ecoregion * EF: experimental forest * canopy_openness: percent openness of forest canopy above each plot as described in the text * weltand_500m: the percentage of the surrounding landscape within 500 m classified as wetland as described in the text * conifer_500m: the percentage of the surrounding landscape within 500 m classified as conifer forest as described in the text * basal_area: basal area of trees (cubic meters per ha) within 0.1 ha circular areas centered on each plot * num_tree_genera: number of tree genera within 0.1 ha circular areas centered on each plot * pollinator_richness: total number of pollinator species collected in each plot * columns with specific pollinator species names provide the number of individuals each captured in each plot as described in the text 2\) The file "merged_data_for_analysis" includes landscape and stand metrics as well as the richness of each pollinator taxa used in the diversity modeling. Column names that may not be obvious, and not listed above, include: * burned2021: indicates whether the plot was burned in 2021 * similar to wetland_500m and conifer_500m, the various land cover metrics show the proportion of the surrounding landscape within the specified distance consisting of each metric as discussed in the text * The various soil texture classes show the proportion of the surrounding landscape within the specified distance consisting of each texture type (note that these data were not used in the analysis) * num_genus: number of tree genera within 0.1 ha circular areas centered on each plot * for columns giving pollinator richness values, these represent the number of species of each specified group captured per plot * for columns giving pollinator abundance values, these represent the number of individuals of each specified group captured per plot * for columns giving pollinator diversity values, these represent the Shannon diversity of each specified group captured per plot (note that these data were not used in the analysis) 3-5) The last three datasets show the incidence of species by pollinator group used in the iNext analysis to compare gamma diversity among the three most-sampled ecoregions. The first row gives the total number of plots within each ecoregion. Subsequent rows represent incidence values for each species, i.e., the number of plots in which each species was collected. ## Code/Software The R Script for running the analysis is provided. The five data files are used in this analysis.