Dirac Twidwell jr.
Date of this Version
ELLERMAN, H. 2020. Vegetation and large carnivore responses in an encroached landscape. M.S. Thesis, University of Nebraska-Lincoln.
The Great Plains biome supports biodiverse plant and animal communities, provides a wide array of ecosystem services, and is depended upon by agricultural economies. Despite these advantages, however, Great Plains grasslands are becoming increasingly degraded by landcover changes due to agriculture and urbanization, fragmentation, loss of biodiversity and invasion by woody species. Woody encroachment is a biome-wide threat to Great Plains plant and wildlife communities and is therefore managed, though with variable success. I investigated the efficacy of invasive tree management projects in restoring tallgrass prairies in southeast Nebraska and regenerating oak gallery forests along the Niobrara River. I measured plant community species composition and frequency at 9 sites in southeast Nebraska to quantify woody reinvasion of restored grasslands. Along the Niobrara River, I surveyed oak-planted plots and quantified oak survival and plant community abundance at 7 sites to determine success of restorations. In each case, restorations had mixed, but mostly negative results. Management decisions following initial treatment of invasive trees compromised the long-term success of restorations. Management is therefore a process, not an action, and must extend beyond initial treatment if restorations are to sustain native plant communities. I also studied habitat use of the newly establishing mountain lion (Puma concolor) as they recolonize Nebraska. I used radio-collar locations of 2 mountain lions to evaluate habitat preferences in a use-availability design. These mountain lions selected riparian woodlands, which will provide dispersal corridors and habitat for breeding populations as mountain lions recolonize the Midwest and eastern North America.
Advisors: Craig Allen and Dirac Twidwell jr.