• Capturing pests and releasing ecosystem engineers: translocation of common but diminished species to re-establish ecological roles

      Swaisgood, Ronald R.; Montagne, J.P.; Lenihan, C. M.; Wisinski, Colleen L.; Nordstrom, Lisa A.; Shier, Debra M. (2019)
      Translocation of abundant but declining ecologically important species for re-establishing more sustainable ecosystem function is a neglected but promising form of conservation intervention. Here, we developed a translocation program in which we capture pests and release ecosystem engineers, by relocating California ground squirrels Otospermophilus beecheyi from areas where they are unwanted to conserved lands where they can perform ecosystem services such as burrowing and vegetation alteration. We accomplished this using an experimental approach in which some factors were measured or experimentally manipulated, while others were held constant. We translocated 707 squirrels and examined survival and movement patterns as a function of several translocation tactics and ecological factors. We released squirrels at 9 different plots with varying ecological contexts and at each plot experimentally manipulated post-release habitat using mowing, mowing plus the use of augers to establish starter burrows, and controls that remained unmanipulated. The most influential variables affecting short-term survival, dispersal, and long-term persistence were factors relating to soils and vegetation structure. Translocated squirrels had higher initial survival on plots where dense exotic grasses were experimentally altered, greater dispersal when released at sites with less friable clay soils, and improved long-term persistence at sites characterized by more friable soils associated with metavolcanic than alluvial geological layers. Squirrel persistence was also improved when translocations supplemented previous translocation sites than during initial translocations to sites containing no resident squirrels. Our results demonstrate how California ground squirrels can be successfully translocated as part of a larger objective to favorably alter ecological function in novel grassland ecosystems dominated by non-native vegetation. In broader context, our study highlights the importance of testing release strategies, and examining habitat variables and restoration techniques more closely when selecting release sites to improve translocation outcomes.
    • Experimental habitat restoration for conserved species using ecosystem engineers and vegetation management

      Hennessy, Sarah McCullough; Deutschman, D. H.; Shier, Debra M.; Nordstrom, Lisa A.; Lenihan, C.; Montagne, J.P.; Wisinski, Colleen L.; Swaisgood, Ronald R. (2016)
      We manipulated vegetation and the ecosystem engineer California ground squirrel, Otospermophilus beecheyi, in a replicated, large-scale field experiment for 2 years, and monitored through a third year…. The overarching goal of this experiment was to provide conservation managers with a cost-effective tool for restoring degraded habitats to a hybrid ecosystem state with improved suitability for species of conservation concern, in this case, the western burrowing owl Athene cunicularia hypugaea.
    • Implications of population and metapopulation theory for restoration science and practice

      Maschinski, Joyce; Quintana-Ascencio, Pedro F (Springer, 2016)
    • Using spatially-explicit population models to evaluate habitat restoration plans for the San Diego cactus wren (Campylorhynchus brunneicapillus sandiegensis)

      Conlisk, Erin; Motheral, Sara; Chung, Rosa; Wisinski, Colleen L.; Endress, Bryan A. (2014)
      A long-standing debate within conservation is how best to allocate limited management resources: should reserve area be increased, should anthropogenic disturbances be mitigated, or should connectivity be increased? We explore these issues for the San Diego cactus wren, a California Species of Special Concern…. Our modeling approach provides insight into the relative benefit of several realistic restoration scenarios, providing an important tool for species conservation and habitat restoration on complex landscapes.