Urban greenspaces, including green roofs and ground-level urban habitats provide habitat for insect communities in cities. However, beneficial insect communities likely differ between human-managed habitats because of varying provision of resources and connectivity in these greenspaces. This study examined the insect communities in four extensive green roofs and three non-adjacent, similarly structured, managed ground-level habitats. We detected a high degree of overlap in insect taxa but found moderate differences in overall insect community composition between the green roof and ground-level habitats. While there was no difference in Shannon diversity between green roofs and ground-level habitats, the ground-level habitat had greater insect taxa richness. Although, both green roof and ground-level habitats supported pollinators and natural enemies, ground-level had greater mean pollinator and natural enemy richness and Shannon diversity. Unexpectedly, green roofs intentionally designed using native plants for habitat did not differ from those that used non-native plants in insect community metrics used in this study. These findings suggest that connectivity and structure might play an outsized role in shaping urban insect communities.

All approaches to biodiversity monitoring have inherent biases in the taxa captured, yet, as environments, sampling goals, and conventions vary, it is not uncommon for sampling approaches to be customized to reflect the study objectives, optimizing findings to be locally relevant but at the cost of transferability. Here, we developed a calibration study to directly examine how researcher trap choice affects observations made in insect biodiversity sampling. Sampling efficiency of four types of traps: pitfalls, yellow ramp traps, a novel jar ramp trap, and yellow sticky cards, were compared with respect to an array of biodiversity metrics associated with the arthropods they captured. We found that trapping efficiency and functional groups of arthropods (flying versus ground-crawling) varied by trap type. Pitfalls and jar ramp traps performed similarly for all biodiversity metrics measured, suggesting that jar ramp traps provide a more comparable measurement of ground-crawling arthropod communities to pitfall sampling than the yellow ramp traps and should be considered when pitfall sampling cannot be used. This study illustrates the implications for biodiversity sampling of arthropods in environments with physical constraints on trapping, and the importance of directly comparing adapted methods to established sampling protocol. Future biodiversity monitoring schemes should conduct calibration experiments to provide important information on performance and potential limitations of sampling methodology.

Natural thin-soil environments are those which have little to no soil accumulation atop hard substrates. Many of these natural thin-soil environments, such as alvars, rocky lakeshores or glades, cliffs and cliff bluffs, and barrens, are found in the Great Lakes Region of North America. Due to their ubiquity and ecosystem services they provide, characterizing insects in sensitive environments such as these is important. This study monitored insects in nine thin-soil sites, within three regions, on a 630 km latitudinal gradient in the Southeastern Great Lakes Region of North America from June - August 2019. Over 22,000 insect specimens collected were identified to order or family, and bee specimens were identified to genus or species. Plants within meter-squared quadrats were identified to genus or species. We found that overall insect community composition and biodiversity characteristics were similar between the three regions examined. However, the southern region differed from the northern and central regions for abundance and evenness, and from the central region for richness. Bee identity was similar across all regions, finding no differences in biodiversity metrics and similar community composition, but with certain taxa unique to each region. Although all regions contained unique plant taxa, insect community characteristics were similar among them. This study provides taxonomic information about the insect, particularly bees, and plant communities in thin-soil environments in this region, which could support conservation and management efforts.