Conservation And Management Of Whitebark Pine Ecosystems PDF Download

In the face of widespread environmental change, understanding and promoting resilience and stability of plant-animal seed disperser mutualisms is key to effective conservation strategies. My two primary objectives were to (1) investigate the response of the keystone mutualism between whitebark pine (Pinus albicaulis) and Clark's nutcrackers (Nucifraga columbiana) to declining habitat in the Greater Yellowstone Ecosystem, and (2) suggest management strategies to help ensure persistence of Clark?s nutcrackers, and their important seed dispersal function. Between 2009 and 2016, I studied Clark?s nutcracker demography and behavioral plasticity by evaluating breeding ecology, space use, seasonal habitat selection and use, foraging ecology, and emigration, as a function of habitat quality and abundance. I carried out occupancy surveys, tracked individuals via radio and satellite, conducted behavioral observations, and monitored nests. Clark?s nutcracker demography and behavior was intimately associated with whitebark pine habitat. Population-wide failure to breed followed low whitebark pine cone crops, and in breeding years, fledging success increased with whitebark pine abundance, but decreased in higher mortality stands. Clark?s nutcracker occurrence was associated with both presence of cone-bearing whitebark pines, and landscape-scale abundance of the pines, suggesting conservation strategies should focus efforts at the landscape scale. The birds selected disproportionately high amounts of Douglas-fir (Pseudotsuga menziesii) habitat for their home range, and foraged heavily on Douglas-fir cones, suggesting that whitebark pine should be managed within a habitat mosaic with Douglas-fir. The Clark?s nutcracker-whitebark pine mutualism appears functional in the region because birds were available to disperse seeds. However, it is unclear whether the mutualism is stable. Clark?s nutcrackers are highly mobile facultative migrants, and the majority of radio- and satellite-tagged birds disappeared during both the 2012 high and 2015 moderate whitebark pine cone crops. Managing Clark?s nutcrackers presents a complex conservation challenge, but I suggest promoting stability of Clark?s nutcracker populations, and focusing on the metapopulation in particular, is necessary for effective whitebark pine conservation. In this dissertation, I conclude by outlining recommended management strategies and key research questions that still need to be answered, finishing with important considerations that should be taken into account when designing a conservation plan for plant-animal seed disperser mutualisms.