<p> Each fall hunters kill hundreds of thousands of White-tailed Deer (<i> Odocoileus virginianus</i>) in Missouri and Illinois. Field dressing these deer provides a large influx of nutrient rich offal into the ecosystem. To date, little research has examined the effects of this resource on wildlife. We used trail cameras positioned over offal piles to examine species richness and diversity in a range of habitats during the 2011-2013 hunting seasons in Missouri and Illinois. There were a total of 17 different sampling sites, resulting in over 4 thousand photographs. Images were analyzed and organized into timed feeding events. Sites were categorized into one of three habitat types: field, edge, or forest. We documented 10 different scavenger species feeding on the offal. There was no significant difference in scavenger diversity (<i>F</i>=2.95; <i>d.f.</i>= 2,14; <i> p</i>=0.085), richness (<i>F</i>=2.25; <i>d.f.</i>2, 14; <i>p</i>=0.14;), nor habitat preference (<i>F</i>=0.51; <i> d.f.</i>2,14; <i>p</i>= 0.61) among habitat types. We also found no significant difference in the community structure of scavengers among the three habitat types (<i>R</i>= -0.049; <i>p</i>=0.64). However, there was a difference in the preferred mean feeding times of avian vs. mammalian scavengers (<i>U</i>=1,215.5; <i>Z</i>=11.24; <i> p</i>=0). The presence of offal piles does not appear to repel deer, as they were frequently observed in close proximity. The apparent similarity of the scavenger guild among habitat types can be attributable to the mosaic of fragmented habitat that characterizes the Midwest, as well as the generalized behavior of the species.</p>

<p> Breeding bird surveys were conducted on 7 properties belonging to 2 ranches in South Texas. Using these data I calculated temporal trends, and tested the effects of total May&ndash;April precipitation and cattle stocking rate on avian abundance. Trends were calculated for each ranch, the East Foundation and King Ranch, individually due to different range and wildlife management practices. Total avian abundance increased significantly on the 3 East Foundation properties between 2008 and 2015. During 39 breeding bird surveys, 16,441 individual birds of 88 species were recorded. Non-breeding bird surveys were also conducted on East Foundation properties, an increasing trend in total avian abundance was also calculated from these data. Total breeding bird abundance was stable on the 4 King Ranch properties between 2005 and 2013. A total of 19,162 individual birds of 87 species were recorded during 40 breeding bird surveys. The combined effect of livestock use and precipitation had a significant effect on total avian abundance on all King Ranch properties, and on the abundance of some individual species and groups. </p>

<p> Being sprayed by the oil produced by the anal glands of the striped skunk (<i>Mephitis mephitis</i>) is known to be strongly aversive to potential predators, which quickly learn to not attack in the future. However, many trap lures use oil from skunk anal glands as an ingredient intended to attract carnivores. This paradoxical nature of skunk oil being both attractive and aversive to potential predators has yet to be investigated, leaving a gap in the understanding of how predators respond to the visual aposematic warning signal of the skunk&rsquo;s pelt in combination with the possibly attractive chemical components of its oil. In this study, camera traps with baited models with either black-and-white or brown pelage, either with or without skunk oil, were deployed in natural areas around Southern California. Results suggest despite its previous use as an attractant for carnivores, the skunk&rsquo;s oil acts as a long distance deterrent while pelt coloration functions as a short distance warning signal.</p>

<p> The Roat&aacute;n Spiny-tailed Iguana (<i>Ctenosaura oedirhina </i>) is endemic to the 146-km² island of Roat&aacute;n, Honduras. Harvesting for consumption, fragmentation of habitat, and predation by domestic animals threaten this lizard. It is currently listed as Endangered by the International Union for Conservation of Nature (IUCN), as threatened by the Honduran government, and is on Appendix II of the Convention on International Trade in Endangered Species (CITES). This species has been geographically fragmented and genetically isolated into small subpopulations that are declining in density. With data gathered from use/availability surveys, resource selection functions were used to identify habitats and environmental variables associated with their presence. Results indicate that protection from harvesting is the most important factor in determining their distribution. These high-density populations are currently restricted to &sim;0.6 km². Organisms living in small, isolated populations with very restricted ranges are at higher risk of extirpation due</p><p> to various direct and indirect forces. Mark-recapture-resight surveys and distance sampling have been used to monitor the populations since 2010 and 2012 respectively. The data show that the high-density populations are declining. The current population size is estimated to be 4130-4860 individuals in 2015. A population viability analysis (PVA) was conducted to identify the most pressing threats and specific life history traits that are affecting this decline. The analysis estimates that if current trends persist, the species will be extinct in the wild in less than ten years. Adult mortality is a main factor and female mortality specifically characterizes this decline. In order for this species to persist over the next fifty years, adult mortality needs to be reduced by more than 50%. A lack of enforcement of the current laws results in the persistence of the main threat, poaching for consumption, thus altering the species distribution and causing high adult mortality. This is complicated by social customs and a lack of post primary education. Management changes could mitigate this threat and slow the population decline. Recommendations include an education campaign on the island, increased enforcement of the current laws, and breeding of <i>C. oedirhina in situ</i> and <i> ex situ</i> for release into the wild.</p>

<p> Globally, amphibians have suffered dramatic population declines in the past twenty years with habitat destruction implicated as the primary threat. The Natural Resources Conservation Service&rsquo;s Wetlands Reserve Program (WRP) restores wetlands on marginal agricultural land and is a means to restore the spatio-temporal wetland habitat required by amphibians to prevent, reverse, or stabilize declining population trends. The goal of WRP is &ldquo;to achieve the greatest wetland functions and values, along with optimum wildlife habitat, on every acre enrolled in the program.&rdquo; Functions and values are defined as the hydrological and biological characteristics of wetlands. A key unanswered question is to what extent is this goal being achieved? Amphibians enable quantifying the WRP goal due to their life-history requirements and explicit incorporation of their habitat needs into WRP plans. My research goal was to determine if hydrological and biological wetland characteristics had been restored to WRP sites in the Lower Grand River basin, north-central Missouri, based on distribution, recruitment success, and relative species richness estimates for members of a regional species pool. I identified three design strategies applied to WRP sites over time: walk-away, maximize hydrology, and naturalistic; the latter emphasizing restoring process as well as structure; and evaluated if design strategy was a useful covariate for restoration efforts. I encountered 10 amphibian species representing 59% of the regional species pool. Design strategy was not a predictive site-level covariate as sites within all three design strategies had varying hydrological wetland conditions resulting in greater habitat heterogeneity than anticipated on maximize hydrology and walk-away sites and less than anticipated on naturalistic sites. Amphibian detections occurred across all sites resulting in no difference among design strategy as the degree of heterogeneity in habitat conditions at the within site-scale demonstrated that amphibians were responding to ecological conditions that occur at a finer resolution than site. Results, irrespective of design strategy, indicate seven of the detected species or groups were widely- distributed, two were moderately- distributed, and two were sparsely distributed on WRP sites indicating hydrological wetland characteristics have been restored to sites given the moderate- to wide-distribution of species associated with both seasonal and permanent wetlands. Although species were successfully recruiting young into adult populations, only leopard frogs had high estimates of recruitment success whereas the remaining species had moderately high to moderate to low recruitment estimates indicating biological wetland characteristics are somewhat lacking to lacking for these species. Results from the relative species richness assessment indicate that, whereas 74% of the sites provided some degree of wetland habitat for members of the regional species pool over the course of the field season (7 March &ndash; 19 September), 52% of the sites lacked suitable habitat conditions during the peak of amphibian breeding and larval development (May through July). Targeting management actions that result in suitable seasonal wetland habitat conditions (shallow, vegetated wetlands that gradually dry by mid-to late-summer) throughout the time needed for species to complete their life history requirements is one method to increase the biological wetland value of restored WRP sites. Results show the value of WRP at conserving and restoring river-floodplain amphibians; however, achieving optimum wildlife habitat on every enrolled acre will be difficult at a site-level scale as habitat requirements, although overlapping, vary widely for the full range of species. Providing for all species in the regional species pool requires sites that transverse both the longitudinal and lateral floodplain gradient. If WRP is to realize its full potential, there must be recognition that optimum wildlife habitat can be defined at multiple spatial and temporal scales that match the landscape setting. Optimum wildlife habitat at a wetland scale is not the same as optimum wildlife habitat at the floodplain scale. The intent of WRP is to convert marginal, flood-prone agricultural lands back into wetlands so enrollment of lands located outside the active floodplain may be impracticable or unrealistic. Whereas attaining optimum wildlife habitat on every acre enrolled in the program may not be an achievable objective, providing optimum wildlife habitat for members of a regional species pool within an appropriately defined geography that includes both a longitudinal and lateral gradient represents an objective that is both desirable and attainable.</p><p>

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 172-196).

<p> The extent of human disturbance is increasing, even in protected areas. I evaluated human disturbance impacts in Murchison Falls Conservation Area (MFCA), Uganda, a park in the Albertine Rift biodiversity hotspot, using two approaches. First, I quantified vegetation patterns and edge effects using remote sensing data in the MFCA interior, a boundary zone, and exterior zone. I observed abrupt changes in productivity between the park and adjacent unprotected areas, indicating a "hard edge", and found evidence of edge effects that extended 4-6 km into MFCA. Second, I evaluated the impact of restored oil pads, roads, the park boundary, and anthropogenic noise on mammal distribution using camera traps and occupancy modeling. Few species avoided, and some were attracted to, more disturbed sites, where restoration may have provided food resources. As human populations continue growing around MFCA and oil production begins, evaluating human disturbance impacts on the landscape will be increasingly important.</p>

<p>Amphibian populations have been declining at higher rates than bird and mammal populations. Agriculture, urbanization, including roads, and resource extraction continue to put pressure on all species. Roads in particular, are major sources of mortality. The Santa Cruz long-toed salamander (<i> Ambystoma macrodactylum croceum</i>), one of the most critically endangered species in the US, is one amphibian that is declining as a result of anthropogenic impacts, especially habitat loss and fragmentation due to urban development. Migration across roads puts these salamanders at risk from road-related death. This thesis quantified the rate of road mortality to these salamanders and other common amphibians during two A. m. croceum breeding-migration seasons in 2011&ndash;13 in a portion of the subspecies' range. Vehicular traffic was a major source of mortality to the salamander. Through traffic doubled the overall vehicle load on roads where the <i>A. m. croceum</i> migrated to and from breeding ponds. The Pacific chorus frog was also killed on the roads. This common species can be used as an indicator of road mortality risk for rarer amphibians. This study indicated that measures to reduce road mortality to the Santa Cruz long-toed salamander could include restricting vehicular traffic on roads adjacent to salamander ponds by limiting traffic to residential use only during breeding migrations, installing structures to protect <i>A. m. croceum</i> while crossing roads, and potentially assisting animals crossing roads at nighttime during the breeding migrations. </p>

Habitat loss and disturbance due to human activity are major causes of global biodiversity decline. Beyond outright species loss, one potential outcome is modification of species interactions that are integral to ecosystem functioning. To investigate this possibility, I asked whether human activity influences avian frugivory and seed dispersal, bird-fruit interactions that facilitate plant reproduction. On Tobago (West Indies), I compared patterns of frugivory in three adjacent rainforest habitats along a gradient of increasing disturbance: primary forest in a reserve, unprotected intermediate forest outside the reserve, and nearby forest that was moderately disturbed by subsistence resource use. I assessed plant and bird community composition, seedling species, fruit removal, and bird fecal samples, to estimate human effects on seed dispersal and plant recruitment in this ecosystem. Disturbed forest had different species assemblages than primary forest, characterized by more light-demanding plants, more birds, and a shift in the relative abundance of avian feeding guilds: insectivores and frugivores declined, while nectarivores and omnivores increased. Canopy cover declined with disturbance; along with plant abundance, this explained much of the variation in bird species composition. The rate of avian fruit consumption in removal experiments varied considerably but tended to be highest in primary forest. Fecal samples showed that fruit composition of avian diets also varied with disturbance; birds captured in disturbed forest consumed more seeds from light-demanding plants. Seeds in the samples provided evidence of some seed transfer between habitats—from disturbed forest into the reserve and vice versa. Seedling composition was consistent with plant species fruiting in the same study plots, and illustrated some successful recruitment of light-demanding plants in primary forest and shade-tolerant plants in disturbed forest. Notably, the plant community of intermediate forest was more similar to disturbed than primary forest. This suggests that habitat adjacent to areas of human activity can be susceptible to ecological change, even though it does not experience the same direct disturbance. In summary, the unprotected portion of Tobago’s rainforest has a markedly different plant and bird community than the forest reserve, and my results indicate that avian frugivory and seed dispersal can be influenced by moderate human activity.

<p> Identity and intensity of parasitism have been shown to be correlated to the host genotype at the major histocompatibility complex (MHC), a genomic region involved in the adaptive immune response. However, the evolutionary mechanisms by which parasites exert a selective force on host immune systems are unknown. This thesis investigates the relationship between parasitism and MHC genotype in two bear populations in Southcentral Alaska. We diagnosed infection using the polymerase chain reaction (PCR), targeting the ribosomal subunit of 18S of common blood parasites. Parasitism was detected in half of brown bears and 75% of black bears. We detected <i>Eimeria</i> spp. and several species of apicomplexan and nematode parasites, and we report here the first finding of <i>Trypanosoma cruzi</i> in Alaskan bears. We found no association between MHC genotype and identity or intensity of infection, suggesting that other loci or even non-genetic factors are important covariates in predicting infection status.</p>