Michael J. Monfils

Habitat Suitability Modeling of the Federally Endangered Poweshiek Skipperling in Michigan

Abstract The Poweshiek skipperling Oarisma poweshiek (Lepidoptera: Hesperiidae) is a historically common prairie butterfly with a range extending throughout the mesic prairies and prairie fens of the upper Midwestern United States and southern Manitoba, Canada. Rapid, range-wide declines have reduced the number of verified Poweshiek skipperling locations to seven, four of which occur in Michigan. To assist with monitoring and, ultimately, conservation efforts, we developed a habitat model using the software Maxent with ecological and geographical factors. Using a lowest-presence threshold methodology, our habitat suitability model indicated potentially high suitability in 26 of 138 prairie fens with no documentation of Poweshiek skipperling occurrence. The strongest predictors of suitable habitat in our model were prairie fen area and surrounding natural land cover. Wildlife managers can use results from this analysis to expand monitoring to include sites with suitable habitat where Poweshiek skipperling ...

Post-Breeding and Early Migrant Bird Use and Characteristics of Diked and Undiked Coastal Wetlands in Michigan, USA

Abstract. Bird use of diked and undiked Michigan coastal wetlands (n = 17) was studied on Lake St. Clair and Lake Huron during late July to mid-October, 2005–2007. Relative abundance and diversity were compared via aerial (n = 9) and ground (n= 155) surveys and wetland characteristics were measured. Species richness and similarity indices suggested analogous bird use, but multivariate analyses indicated significant separation in diked and undiked bird assemblages. Wood Duck (Aix sponsa), Great Blue Heron (Ardea herodias), and Wilsons Snipe (Gallinago delicata) were more abundant on diked sites, whereas dabbling ducks combined, Mallard (Anas platyrhynchos), American Black Duck (A. rubripes), gulls (Laridae), Forsters Tern (Sterna forsteri), and Greater Yellowlegs (Tringa melanoleuca) were more abundant on undiked wetlands. Wetland characteristics also differed. Diked sites were primarily cattail (Typha spp.) marshes interspersed with small open-water areas containing aquatic plants. Undiked sites had larger openings fringed with bulrushes (Schoenoplectus spp.), fewer aquatic plants, and direct lake connections. Periodic drawdowns of diked wetlands could encourage greater plant species and structural diversity, making them more attractive to dabbling ducks. However, risk of common reed (Phragmites australis) expansion is high in the study areas, thus its control may be necessary before enhanced management can occur.