Environmental associations of Hesperia dacotae (Lepidoptera: Hesperiidae) in southeastern Saskatchewan, Canada

The Dakota skipper, Hesperia dacotae (Skinner, 1911) (Lepidoptera: Hesperiidae), is an at-risk butterfly that inhabits mesic mixed-grass prairie. Loss of native prairie is the main factor driving declines in Dakota skipper abundance. Currently, there is little knowledge on the environmental and habitat requirements of Saskatchewan, Canada populations. Our objective was to determine environmental associations of Dakota skipper in Saskatchewan through landscape, vegetation, soil, climate, microclimate, and Hesperiidae butterfly occupancy. Data collection was conducted in 2015 and 2016; a total of 46 sites were surveyed; nine of these were Dakota skipper positive (i.e., present) sites and 37 were negative (i.e., non-detected) sites. Results indicate that plant composition is not a significant predictor of Dakota skipper presence, but three plant species are significantly associated with the species; Pediomelum argophyllum (Pursh) Grimes (Fabaceae), Zizia aptera (Gray) Fernald (Apiaceae), and Schizachyrium scoparium (Michaux) Nash (Poaceae). No soil or climate variables were significant predictors of Dakota skipper presence; however it is significantly associated with steep slopes. Warmer maximum and average ground-level temperatures are also associated with Dakota skipper presence. Findings indicate that additional Dakota skipper populations are likely in Saskatchewan and future targeted surveys will allow for a full evaluation of the distribution of this species and conservation status.