It is critical to understand the specific drivers of biodiversity across multiple spatial scales, especially within rapidly urbanizing areas, given the distinct management recommendations that may result at each scale. However, drivers of biodiversity patterns and interactions between drivers are often only measured and modeled at a single scale. In this study, we assessed bee community composition at three time periods in 20 grassland and 20 agriculture sites located across two major metroplexes. We examined how local environmental variables and surrounding landscape composition impact bee abundance, richness, and evenness, including comparisons between groups with different nesting strategies and body sizes. We collected nearly 13,000 specimens and identified 172 species. We found that levels of regional land use differentially impacted bee abundance and diversity depending on local habitat management. Specifically, within agriculture sites, bee richness was greater with increasing landscape‐level seminatural habitat, while in grassland sites, bee richness was similar across landscapes regardless of seminatural habitat cover. Bee evenness at both site types declined with increasing landscape‐level habitat heterogeneity, due to an increase of rare species at the grassland sites, but not in the agricultural sites, further indicating that diversity is driven by the interaction of local habitat quality and landscape‐level habitat composition. We additionally found that agriculture sites supported higher abundances, but not richness, of small‐bodied and below‐ground nesting bees, while grassland sites supported higher abundances of aboveground nesting bees, and higher richness of large‐bodied species. Increased levels of local bare ground were significantly related to multiple metrics of bee diversity, including greater belowground nesting bee abundance and richness. Local floral richness was also significantly related to increases of overall bee abundance, as well as the abundance and richness of small bees. Overall, we suggest that local land managers can support bee abundance and diversity by conserving areas of bare soil and promoting native floral diversity, the latter especially critical in highly urban agricultural spaces. Our results provide the first documentation of significant interactions between local habitat management and landscape composition impacting insect communities in urban systems, indicating that bee conservation practices depend critically on land use interactions across multiple spatial scales.

DNA sequencing technologies continue to advance the biological sciences, expanding opportunities for genomic studies of non‐model organisms for basic and applied questions. Despite these opportunities, many next generation sequencing protocols have been developed assuming a substantial quantity of high molecular weight DNA (>100 ng), which can be difficult to obtain for many study systems. In particular, the ability to sequence field‐collected specimens that exhibit varying levels of DNA degradation remains largely unexplored. In this study we investigate the influence of five traditional insect capture and curation methods on Double‐Digest Restriction Enzyme Associated DNA (ddRAD) sequencing success for three wild bee species. We sequenced a total of 105 specimens (between 7–13 specimens per species and treatment). We additionally investigated how different DNA quality metrics (including pre‐sequence concentration and contamination) predicted downstream sequencing success, and also compared two DNA extraction methods. We report successful library preparation for all specimens, with all treatments and extraction methods producing enough highly reliable loci for population genetic analyses. Although results varied between species, we found that specimens collected by net sampling directly into 100% EtOH, or by passive trapping followed by 100% EtOH storage before pinning tended to produce higher quality ddRAD assemblies, likely as a result of rapid specimen desiccation. Surprisingly, we found that specimens preserved in propylene glycol during field sampling exhibited lower‐quality assemblies. We provide recommendations for each treatment, extraction method, and DNA quality assessment, and further encourage researchers to consider utilizing a wider variety of specimens for genomic analyses.

A core goal of ecology is to understand the abiotic and biotic variables that regulate species distributions and community composition. A major obstacle is that the rules governing species distributions can change with spatial scale. Here, we illustrate this point using data from a spatially nested metacommunity of parasites infecting a metapopulation of threespine stickleback fish from 34 lakes on Vancouver Island, British Columbia. Like most parasite metacommunities, the composition of stickleback parasites differs among host individuals within each host population, and differs between host populations. The distribution of each parasite taxon depends, to varying degrees, on individual host traits (e.g., mass, diet) and on host‐population characteristics (e.g., lake size, mean host mass, mean diet). However, in most cases in this data set, a given parasite was regulated by different factors at the host‐individual and host‐population scales, leading to scale‐dependent patterns of parasite‐species co‐occurrence.

Human activity continues to impact global ecosystems, often by altering the habitat suitability, persistence, and movement of native species. It is thus critical to examine the population genetic structure of key ecosystem‐service providers across human‐altered landscapes to provide insight into the forces that limit wildlife persistence and movement across multiple spatial scales. While some studies have documented declines of bee pollinators as a result of human‐mediated habitat alteration, others suggest that some bee species may benefit from altered land‐use due to increased food or nesting resource availability; however, detailed population and dispersal studies have been lacking. We investigated the population genetic structure of the Eastern carpenter bee, Xylocopa virginica, across 14 sites spanning more than 450 km, including dense urban areas and intensive agricultural habitat. X. virginica is a large bee which constructs nests in natural and human‐associated wooden substrates, and is hypothesized to disperse broadly across urbanizing areas. Using 10 microsatellite loci, we detected significant genetic isolation by geographic distance and significant isolation by land‐use, where urban and cultivated landscapes were most conducive to gene flow. This is one of the first population genetic analyses to provide evidence of enhanced insect dispersal in human‐altered areas as compared to semi‐natural landscapes. We found moderate levels of regional‐scale population structure across the study system (Gʹ_ST = 0.146) and substantial co‐ancestry between the sampling regions, where co‐ancestry patterns align with major human transportation corridors, suggesting that human‐mediated movement may be influencing regional dispersal processes. Additionally, we found a signature of strong site‐level philopatry where our analyses revealed significant levels of high genetic relatedness at very fine scales (<1km); surprising given X. virginica’s large body size. These results provide unique genetic evidence that insects can simultaneously exhibit substantial regional dispersal as well as high local nesting fidelity in landscapes dominated by human activity.

Land use change threatens global biodiversity and compromises ecosystem functions, including pollination and food production. Reduced taxonomic α‐diversity is often reported under land use change, yet the impacts could be different at larger spatial scales (i.e., γ‐diversity), either due to reduced β‐diversity amplifying diversity loss or increased β‐diversity dampening diversity loss. Additionally, studies often focus on taxonomic diversity, while other important biodiversity components, including phylogenetic diversity, can exhibit differential responses. Here, we evaluated how agricultural and urban land use alters the taxonomic and phylogenetic α‐, β‐, and γ‐diversity of an important pollinator taxon—bees. Using a multicontinental dataset of 3117 bee assemblages from 157 studies, we found that taxonomic α‐diversity was reduced by 16%–18% in both agricultural and urban habitats relative to natural habitats. Phylogenetic α‐diversity was decreased by 11%–12% in agricultural and urban habitats. Compared with natural habitats, taxonomic and phylogenetic β‐diversity increased by 11% and 6% in urban habitats, respectively, but exhibited no systematic change in agricultural habitats. We detected a 22% decline in taxonomic γ‐diversity and a 17% decline in phylogenetic γ‐diversity in agricultural habitats, but γ‐diversity of urban habitats was not significantly different from natural habitats. These findings highlight the threat of agricultural expansions to large‐scale bee diversity due to systematic γ‐diversity decline. In addition, while both urbanization and agriculture lead to consistent declines in α‐diversity, their impacts on β‐ or γ‐diversity vary, highlighting the need to study the effects of land use change at multiple scales.