Habitat Characterization and Biology of the Threatened Dakota Skipper (Hesperia dacotae) in Manitoba

• Main Author: Rigney, Christa Leigh
• Format: Thesis
• Language: English
• Published: University of Winnipeg 2013
• Subjects: Dakota skipper > Manitoba; Wildlife conservation > Manitoba; Dakota skipper; Hesperia dacotae; butterflies; habitat characterization; Manitoba; endangered species; life history; soil characterization; butterfly survey; Canada; Campanula rotundifolia
• Online Access: http://hdl.handle.net/10680/576

The Dakota Skipper, Hesperia dacotae, is a threatened butterfly restricted to fragmented prairies in the Interlake, southwestern Manitoba and southeastern Saskatchewan in Canada. Currently there is limited data on the life history and habitat requirements in Canada to implement effective conservation measures. The purpose of this study was to determine key biological and physical habitat requirements within existing Dakota Skipper sites in Manitoba. Four Dakota Skipper sites in the Interlake and four sites in southwestern Manitoba were selected to measure the composition of vegetation and flowers in bloom during the flight period, and soil characteristics. Adult populations were also surveyed at each site. Sites were generally subject to annual fall haying and several sites exhibited adverse impacts associated with flooding, succession, encroachment by invasive plants, vehicle damage, cattle grazing or wildfire. There was considerable overlap in vegetation and flower composition between sites, and between the Interlake and southwest Manitoba regions. The most abundant plant species at sites in the vegetation surveys included: Agropyron repens, Andropogon gerardii, Andropogon scoparius, Deschampsia caespitosa, Poa compressa, Poa cusickii, Scolochloa festucacea and Sonchus arvensis. In the flower surveys the most abundant plants included: Zygadenus elegans, Melilotus alba, Petalostemon candidum, Petalostemon purpureus, Campanula rotundifolia, Lobelia spicata, Crepis runcinata, Rudbeckia hirta and Solidago ptarmicoides. Four previously documented and ten possible larval food plant species were recorded as well as 34 previously documented or possible adult nectar plant species. There was no significant difference between regions in plant species diversity measures (Shannon diversity, Shannon eveness, Simpson reciprocal and Berger-Parker reciprocal indices). Indicator Species Analysis identified ten species in the vegetation surveys and 15 species in the flower surveys as significant regional indicators. Principal ...