The Ecology and Conservation of the Critically Endangered Cross River Gorilla in Cameroon

摘要: Author(s): Sawyer, Sarah | Advisor(s): Brashares, Justin Abstract: The Cross River gorilla (Gorilla diehli; hereafter: CRG) is one of the world's most endangered and least studied primates. CRG exist only in a patchy distribution southern portion Cameroon-Nigeria border region may have as few 300 individuals remaining, divided into 14 fragmented subpopulations. Though Western gorillas spp) probably once inhabited much greater ranges throughout West Africa, today represent northern western all are isolated from lowland populations by more than 250 km. proved challenging to study protect, many remaining subpopulations currently outside protected areas. Very little known about where various range on landscape or why they occur within seemingly intact habitat. Active efforts underway identify critical habitat for conservation protect this biodiversity hotspot but, date, lack understanding relationship between ecology available has hampered endeavors. This dissertation aims improve our inform management decision making. research four main components. First, I describe plant diet subpopulation (the Mone subpopulation). Successful primate requires which plants important how these vary availability across landscape. Using feeding trail sign collected over 10 month period, record components diet, evaluate selectivity among herbaceous food species, compare that another subpopulation, examine differences areas used unused CRG. During ate 141 different parts 102 23 were quantitatively diet. Similarly other populations, Landolphia, Aframomum, Palisota spp, staple species Marantochloa purpurea played an fallback role their By contrast, Araceae like Cercestis camerunensis, be at elsewhere. My results suggest Mone-Mt. Oko prefer certain foods also selectively use with higher preferred foods. Second, estimate assess both effects model choice resulting estimates utility models. Measuring characterizing area utilized population essential evaluation status effective allocation ensure persistence. Models considered basic traditional approaches (e.g. Minimum Convex Polygon) newer home techniques such Local Hull (LoCoH). overlap analysis comparing sub-sampled complete data sets robustness modeling limitations. employed Likelihood Validation Criterion core performance. Results differing LoCoH models produce similar estimates, robust requirements, provide good fit estimation, best able detect range. methods thus useful studies selection factors limiting distributions. However, tend overfit data, Kernel information animal space while supporting protection larger swaths Subpopulation analyses conservation/management planning should therefore explore multiple techniques, employ qualitative quantitative assessments select making concern.Third, review current Least Cost Path connectivity conservation, highlight weaknesses ways application gorilla. Promoting maintain viability CRG, each contains relatively individuals. common approach design (LCP) analysis, been applied highlights three recent LCP analyses. typically rely remotely-sensed maps, but whether maps suitable proxies affecting movement consider adjacent habitats. Secondly, expert opinion assign costs associated features, yet validate empirical sensitivity errors cost assignment. Thirdly, multiple, alternative paths often propose width length requirements linkages without justification. modelling linkage guide planning, biological foundation. Ecologists must clarify processes resistance values based, explicitly justify schemes scale (grain) context schemes, strive optimize data. Research relating species' fine-grain broad extents desperately needed, determine biologically relevant restrictions linkages. While fine grain date lacking gorilla, variables.Thus, finally, hierarchical resource functions (RSFs) scales planning. Specifically, generalized additive conditional logistic regression individual movements. Understanding will better habitat, indicate highly dependent. Localized measures quality strongly influenced scale, human activity predictors finer scales. do not crucial designating require integrative, multi-scale incorporating large-scale characteristics, patterns availability. Further fine-scale collection necessary RSF subpopulations.This marks significant addition limited knowledge dietary spatial biology. complement past ongoing PhD students, NGOs, government officials, compiling works likely us