The Oak Openings Region of Northwest Ohio is a mosaic of globally rare communities including oak savannas and woodlands. The perennial wild blue lupine (Lupinus perennis) in the Oak Openings Region is an important nitrogen fixer and serves as an essential food source for the larvae of federally endangered Karner Blue butterfly (Lycaeides melissa samuelis). Therefore there is interest in managing wild lupine and understanding what factors affect lupine in this oak savanna-woodland mosaic. We focused on potential factors that might be affecting mice predation on wild lupine seeds. Preliminary data indicated that white-footed mice predate upon wild lupine seeds, and we hypothesized that this contributed to the lupine’s potentially threatened status in Ohio. We questioned if seed predation occurred in an area was related to vegetation, edge, land management, or mice abundance. We used mark-recapture to estimate mice abundance, site surveys for lupine abundance, and 8 inch diameter screen covered seed trays with small mammal entrances to track amount of seed predation occurring. Using this information, we assessed the severity of seed predation. Vegetation surveys were conducted to evaluate the surroundings and tracking tubes were laid out to get a more complete consensus on mice distribution. A logistic regression with all these factors was used to evaluate the predictors of seed predation.
Results/Conclusions
For the field season (May-August) average seed predation was 22% across all sites. Increased vegetation density was the factor that best predicted seed predation (P = 0.0385). Seed predation did not differ between the edge habitat and oak savannas, but was significantly different between oak savanna sites (P = 0.015). Average seed predation over time was significantly different depending on number of prescribed burns over the last 5 and 10 years ( P = 0.018, 0.004), but not during the 2008 season, suggesting a potential lag in the effect of management practices. Predation increased with burns but leveled off as burns increased. Overall, increased prescribed burns and vegetation density correspond with increased seed predation. Therefore, prescribed burns could be used to manage levels of lupine seed predation by mice.
