Browsing by Subject "Occupancy"
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Item Open Access Use of Site Occupancy Modeling to Delineate a Jaguar Corridor in Southern Belize(2010-04-28T20:08:08Z) Petracca, Lisanne S.This analysis, a component of Panthera's Jaguar Corridor Initiative, incorporated 184 interviews with local hunters and farmers in a site occupancy framework to determine the likelihood of jaguar and jaguar prey occupancy in 90 16-km2 grid cells in the Toledo District of southern Belize. This output was compared with that of Maxent, a presence-only species distribution modeling technique, to determine if both approaches led to similar conclusions. Site occupancy analysis revealed that jaguar occupancy was associated with percent daily chance of seeing armadillo, higher elevation, and proximity to protected areas and forest cover. Prey species analysis revealed that likelihood of white-lipped peccary (Pecari tajacu) occupancy was associated with greater forest cover and proximity to protected areas and water/wetlands; collared peccary (Tayassu pecari) occupancy with greater forest cover and proximity to agriculture and settlements; red brocket deer (Mazama americana) occupancy with greater forest cover, proximity to agriculture, and higher elevation; and armadillo (Dasypus novemcinctus) occupancy with greater agricultural area, lower elevation, and greater distance from water/wetland. Site occupancy models were unable to be fitted for the paca (Agouti paca) and white-tailed deer (Odocoileus virginianus) populations. Following the weighting of jaguar output to 2.0 and prey species output to 1.0, total Psi (probability of occupancy) was calculated for each of the 90 grid cells. Cells with the maximum possible Psi value (meaning that the jaguar and all modeled prey species were present) were identified, and the final cells were chosen from this subset based on having relatively low future threat. These cells were cross-checked with Maxent output to ensure that the corridor contained areas of high habitat suitability. The proposed corridor extends along the eastern flank of the Toledo District and connects Sarstoon-Temash National Park with the protected areas of local NGOs TIDE (Toledo Institute for Development and Environment) and YCT (Ya’axche Conservation Trust). The analysis concludes with recommendations and concerns specific to the communities that fall within the corridor.Item Open Access Viability and improvement of constructive wildlife corridors in tropical forests, proposing a new method for evaluating corridors geospatially using MaxEnt(2022-12-14) Markus, CaitlinHabitat corridor ecology remains a new and developing field in wildlife and forest management. Little is known about how corridors statistically work or how they should be established and monitored. Stuart Pimm and his non-profit Saving Nature build constructive habitat corridors in tropical forests, and he now hopes that the data collected from these corridors can contribute to the growing knowledge in this field. In this study, I analyzed camera trap data from Saving Nature’s corridors in Colombia, Ecuador, and Brazil. Occupancy models were run to determine general corridor efficiency based on the species detected in the camera traps and species that were expected to appear based on environmental variables. I also attempted to propose maximum entropy models as an alternative way to achieve the same goal. Finally, least cost path corridor models were run to identify the areas animals are most likely to be found in, so that cameras can be repositioned to collect more data. Overall, all corridors were determined to be working adequately, but with room for improvement. MaxEntmodels show some potential as a method to evaluate corridor projects, but model refining and further research and development are required.