Browsing by Author "Smolensky, Nicole Limunga"
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Item Biodiversity Conservation in Sub-Saharan Africa: A Case Study of the African Dwarf Crocodiles (Osteolaemus Spp.)(2014-11-20) Smolensky, Nicole LimungaOverexploitation of wildlife is a leading threat to biodiversity in tropical Africa. Effective management requires integrating information on the extent of exploitation, distribution, and status of exploited species. I explore how trade filters affected the final destination of bushmeat for different species involved in the trade. I highlight the trade in reptiles, in particular African Dwarf Crocodiles (Osteolaemus tetraspis) to investigate why they are rare in markets yet ubiquitously hunted. Hunting locations and methods determined the types of species entering bushmeat markets while selling conditions and prices determined whether species were traded locally or in urban markets. To prioritize conservation efforts of over-exploited species, it is important to determine the distribution and status of populations. I conducted detailed sampling of Osteolaemus populations in Cameroon and around the Cameroon Volcanic Line (CVL), to investigate the distributional limits and number of cryptic Osteolaemus species in the country. I found that O. tetraspis extends west beyond the CVL, thus, this mountain chain does not represent the distributional limit of this species. I also found O. osborni in Cameroon. I provided information on the population ecology of O. tetraspis and O. osborni in Cameroon to facilitate independent conservation of these two species. Both species are threatened in Cameroon based upon low encounter rates, young population structures and continued threats of habitat loss and hunting pressure. Crocodilians link nutrients and energy between food webs through their movements across heterogeneous habitats. These connections may differ among habitats and as they undergo ontogenetic shifts in diet. I compared food web associations of Ostoelaemus species inhabiting a large river and small tributary using stable isotope analyses of carbon and nitrogen. Osteolaemus species inhabiting perennial rivers have aquatic food web associations as opposed to the largely terrestrial food web associations detected when they occupy swamp habitats. These species have large dietary overlap between juveniles, adults and, sexes. Through my research, I have provided a working knowledge of the distribution, ecology, and hunting pressure of Osteolaemus species necessary for assessing their conservation status and developing sound management. These widely distributed species should be regionally managed to conserve their evolutionary diversity.Item Population enumeration and the effects of oil and gas development on dune-dwelling lizards(2009-05-15) Smolensky, Nicole LimungaHabitat loss is one of the leading causes of species decline across all taxa and conservation practices require information on population trends. The Mescalero Sands ecosystem, New Mexico, USA, is experiencing landscape changes associated with oil and gas development. The dune-dwelling lizard community contains a habitat specialist, Sceloporus arenicolus, that is of particular interest because it has a very limited geographic distribution that is entirely subject to oil and gas development. Distance sampling is widely used to estimate population densities of many vertebrate taxa however assumptions can be difficult to satisfy with certain species or in certain habitats. Researchers must investigate the likelihood that assumptions can be satisfied before implementing any population sampling method. I had two objectives. First to investigate the precision of population densities of dune-dwelling lizards estimated via distance sampling that was coupled with double-observer surveys. Second to compare abundances of dune-dwelling lizards among sites that varied in oil and gas development. I conducted distance line transects and compared those density estimates to densities obtained from total removal plots. I quantified the amount of oil and gas development, habitat quantity and quality and correlated those to lizard abundances to investigate the effects of oil and gas development on lizard populations. I found large differences in density estimates from distance sampling and total removal plots that resulted from violation of distance sampling assumptions. Although distance sampling is a low cost method, it does not produce reliable density estimates for dune-dwelling lizards and is not an appropriate sampling method in this system. I did not find oil and gas development effects on the habitat quantity, quality or on the abundances of lizards. Lizard abundances were most strongly correlated to habitat quantity. Lizard abundances may be influenced by complex interactions between oil and gas development and habitat quantity and quality but controlling for those interactions was beyond the scope of my study. Before and after experiments and long-term studies at multiple sites would be required to more fully address the effects of oil and gas development on lizard populations in the Mescalero Sands.