Climate gradients, and patterns of biodiversity and biotic homogenization in urban residential yards

Residential yards constitute a substantive biodiverse greenspace within urban areas. This biodiversity results from a combination of native and non-native species and can contribute to biotic homogenization. Geographical climatic patterns affect the distribution of native species and may differently affect non-native species. In this study, we examined biodiversity and biotic homogenization patterns of yard-dwelling land snails across 12 towns in Oklahoma and Kansas (USA). The 3 x 4 array of towns incorporated a N-S winter temperature gradient (mean low January temperature range = -8.4 to 0.1°C) and an E-W annual rainfall gradient (annual rainfall range = 113.8 to 61.3 cm/yr). Ten yards per town were surveyed. We hypothesized that mild winter temperatures and greater annual rainfall would be associated with greater snail abundance and richness, and that the presence of non-native species would contribute to biotic homogenization. Non-native snails were present and often abundant in all towns. Snail communities varied with both rainfall and cold temperature. Contrary to our prediction, snail abundance was inversely related to annual rainfall–likely because drier conditions resulted in greater yard watering that both augmented rainfall and maintained moist conditions. Sørensen similarity between towns for the entire land snail community and for only non-native species both showed distance-decay patterns, with snail composition becoming less similar with increasing distance—patterns resulting from species turnover. The biotic homogenization index also showed a distance-related pattern, such that closer towns were more likely to have biotic homogenization whereas more distant towns tended to have biotic differentiation. These results support the concept that biotic homogenization is more likely regionally and that climatic changes over distance result in species turnover and can reduce spatially broad biotic homogenization.Funding was provided by the University of Oklahoma: SRI funds, Oklahoma Biological Survey small grants program, and University Libraries (all to EAB). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Open Access fees paid for in whole or in part by the University of Oklahoma LibrariesYe

Arbuckle hydroptilid (caddisfly) database

Species composition and site data for the 2017-2018 hydroptilid survey in southern Oklahom

Urban snails in Oklahoma: select non-native species

This project includes 2 documents: an Excel database of records for 4 snail species and a flow chart key to commonly encountered snails in urban habitats in Oklahoma

Watercress springs survey datasets

This project contains the data associated with the manuscript on the ecosystem effects of watercress in spring

Washita River at WBNHS aquatic insect data

The data spreadsheet shows the light trap data for aquatic invertebrates (EPT: Ephemeroptera, Trichoptera, and Plecoptera) on two dates: 28 June and 22 Aug 2022. UV-light traps were set on the riverbank of the Washita River in the Washita National Battlefield Historic Site (Roger Mills County, Oklahoma) for 1 to 3 hours after sunset. EPT taxa were identified by Boris Kondratieff (Ephemeroptera and Plecoptera) and David Ruiter (Trichoptera)

Land snail survey at the Oklahoma City Zoo 2023

Snails were surveyed in April and May, with a total of 24 sites. Data consist of site descriptions (location, date, and and habitats) and the snails found at each site. Two outreach documents (a key to common soil-associated invertebrates and a short activities list) are also included