Invasive species can have a variety of effects on the behavior and ecology of native species. Currently in New Orleans, Louisiana, both A. sagrei and A. carolinensis lizards are relatively abundant, but the A. sagrei population is expanding rapidly. I used a combination of laboratory and field studies to investigate factors that might be influencing local dominance of invasive A. sagrei over native A. carolinensis populations, including habitat use, display behavior, interspecific aggressive interactions, and plasticity. When comparing display behavior and habitat use in anole populations across three field sites in southern Louisiana, I found differences in male display behavior of both species, and also that A. carolinensis perched higher when A. sagrei was present. In staged interspecific interactions, I discovered that A. sagrei females achieved consistently higher aggressive scores than A. carolinensis females, suggesting that female interspecific behavior is probably more important than male behavior in driving changes in habitat use. Lastly, I studied plasticity in several morphological and whole-organism performance variables by rearing males and females of each species on two different perch diameters. I found that sprinting performance in A. sagrei was significantly different between treatment groups, although the morphological differences between perch treatments were subtler than those reported in previous studies. I also found that A. carolinensis females exhibited significant differences in both sprinting and clinging performance, despite no significant differences in male or female morphology between perch size treatments, highlighting the potential for both species-specific and sex-specific plasticity.

Swamp-breeding treefrogs form conspicuous components of many tropical forest sites, yet remain largely understudied. The La Selva Biological Station, a rainforest reserve in Costa Rica, harbors a rich swamp-breeding treefrog fauna that has been studied in only one of the many swamps found at the site. To understand if the species composition of treefrogs at La Selva varies over space or time, frogs were censused in 1982-83, 1994-95, 2005 and 2011 at two ponds located in the reserve. Data on treefrog habitat utilization were also collected. Species composition varied spatially only in 2011. Temporal variation was observed at both ponds for all groups tested. Habitat use varied among species and between swamps. The pattern of variation suggests that temporally dynamic systems such as temporary Neotropical forest swamps will converge and diverge in species composition over time.

Bottlenose dolphins (Tursiops truncatus) are large-bodied predators that are locally abundant in the coastal Everglades. Because of their potential to exert strong top-down effects on their communities, it is important to understand how spatiotemporal variation in biotic and abiotic factors affects the abundance and behavior of dolphins. This study combined two years of transect surveys with photographic identification methods to assess spatiotemporal variation in the abundance and group sizes of bottlenose dolphins across four large regions of the coastal Everglades including the Shark and Harney Rivers, Whitewater Bay, and coastal oceans of the Gulf of Mexico and Florida Bay. Dolphin abundance was similar across wet and dry seasons, except in river habitats where abundances were higher during the dry season. Group sizes were largest in Florida Bay and open water. Dolphins may be relatively resilient to abiotic changes in the coastal Everglades, with the possible exception of river habitats.

As habitat loss and fragmentation are major causes of decline in animal species, studying habitat requirements in these species is a key component of their recovery. I investigated the relationship between landscape composition and habitat use of Blanding’s turtles, Emydoidea blandingii, a freshwater turtle threatened by habitat loss and road mortality on most of its Canadian range. In 2010, I conducted a radio-telemetry survey of 44 Blanding’s turtles in southern Québec, Canada, and modelled their home range size from land cover proportions measured at many spatial scales. I also used data from a visual survey conducted in 2008 and 2009 to model wetland occupancy of the species at the landscape scale. Home range size of the Blanding’s turtle was significantly correlated to landscape composition, and the proportions of agriculture, open water and anthropogenic lands had the strongest relationships with home range size. However, those relationships were weak and the models were unable to predict home range size accurately. At the landscape scale, land cover and road density poorly predicted probability of occurrence, and Blanding’s turtles occupied wetlands in both disturbed and natural sites. Management of the species should focus on protecting sites of occurrence with high wetland density, low road density, and sufficient suitable habitat to cover their seasonal movement patterns.

The perception of increased predation risk by nocturnal mice and other small mammals has been shown to reduce activity levels, particularly in foraging effort. Various cues of predation risk have been used in previous studies, but few have assessed the potential interactions between different types of cues. I conducted field, laboratory, and enclosure experiments using predator scents, artificial light, and microhabitat variables to determine the effects of direct and indirect cues of predation risk on foraging behavior in wild nocturnal mice. Experimental foraging trays served as artificial resource patches, and giving-up densities were measured in order to test for foraging persistence in patches exposed to cues of predation risk. Cotton mice (Peromyscus gossypinus) were used in laboratory and enclosure trials, and were the most common mice present at the sites used for field trials. Although previous foraging studies have used other Peromyscus species, this species has not been tested, but ranges over densely populated areas of the United States where artificial light could potentially affect its behavior. In outdoor and laboratory enclosures, cotton mice showed no aversive response to bobcat urine, cloths rubbed on cats, or snake sheds, but did exhibit avoidance of cat fur and artificial light. In the field experiment, mice showed a strong preference for covered microhabitats, but did not avoid bobcat urine or artificial light. Foraging in artificial resource patches also increased throughout the duration of the field experiment, possibly coinciding with a reduction in naturally-available forage. Mice in this population appear to use cover as their primary means of avoiding detection or capture by predators, though they do avoid artificial light and at least one fur-derived odor when their available options for escape are reduced.

Across the western United States, most populations of Rocky Mountain elk (Cervus canadensis) are managed through hunter harvest (Sandrey 1983). In hunted populations, human harvest is the leading source of mortality (Ballard 2000). With the exception of elk in national parks, populations are primarily managed through hunter harvest. Other sources of mortality include disease, automobile collisions, and predation from mountain lions, coyotes, wolves, and black bears (Childress 2003, Hornocker 1970). As a species of management concern and high economic value (Pickton 2008), hunted populations of elk are carefully managed to target population sizes to guarantee a sustainable supply and ensure available harvest in the future. Estimates of survival, an understanding of cause-specific mortality, and knowledge of high-risk harvest areas are essential to effective management strategies (Stussy 1994). In the first chapter, I examined habitat use of elk during the hunting season and determined habitat characteristics that best predicted vulnerability to harvest. In the second chapter, I calculated annual survival and determined cause-specific mortality of elk.

The semiaquatic mammals - amongst them the beaver Castor fiber - are inhabitants of the land-water-ecotone, which is characterized by length and low depth.Due to specific adaptations to their habitats, semiaquatic mammals are highly dependent on the specific structures and resources of the ecotone riverbank. Anthropogenic influences on the ecotone riverbank often cause destruction of the resources that leads to a decrease of structural diversity.Being a primary consumer, the beaver mainly uses the water as a medium for locomotion and escape. The equipment of the riverbank, mainly the bankside vegetation, is of great importance concerning foraging. The presence and the quantity of certain biofacts like feeding or cutting places and scent mounds give a hint on the value of different structures and resources of the bankside with regard to certain modes of behaviour. They also give information on different qualities of the used and unused parts of the bankside.Biofacts of beaver-activity were recorded along 20 km of riverbank during a five-year-period. The results of the statistical analysis show that beavers - concerning species-specific mode of behaviour - prefer certain riverbank structures. Biofacts and near-natural structures such as steep bank, riparian forest and willows correlate significantly positive whereas biofacts and anthropogenic structures as slope, farmland or absence of woody plants show significantly negative correlation. There is a strong connection between the number of biofacts - that is use of the riverbank or slope - and structural diversity. Based on these results, an eco-ethological model has been developed which makes it possible to predict behaviour in dependence on the specific structures and resources of the banks and slopes of anthropogenic influenced streams.

Translocations have been used as a management strategy to successfully augment declining native wildlife populations. Greater sage-grouse (Centrocercus urophasianus; sage-grouse) population declines on Anthro Mountain, Utah prompted managers to translocate sage-grouse and test protocols from a successful translocation project in Strawberry Valley, Utah. Sage-grouse from Parker Mountain, Utah were used as the source population for Anthro Mountain and Strawberry Valley translocations. Sixty hens were translocated to Anthro Mountain in 2009 and 2010; I monitored vital rates of the 60 translocated hens and 32 resident hens from 2009-2012. My objective was to determine the overall success of the translocation 4 years after the initial release and compare vital rates to the source population and Strawberry Valley.In Chapter 2, I determined that survival varied by study area and hen age but was not affected by residency status. Annual survival of Anthro Mountain hens was lower than Parker Mountain and Strawberry Valley hens. Adult hen survival in all three populations was higher than yearling survival.In Chapter 3, I determined that the translocation contributed to population growth. Adult resident and previously translocated hens had the highest reproductive success, followed by resident yearlings, newly translocated adults, and newly translocated yearlings. Lek counts increased from 2009-2013 and a new lek was discovered in 2011. Survival was not affected by residency status or age, but varied greatly by year and season. Mean monthly survival was lowest in the fall; this differs from range-wide trends.In Chapter 4, I determined that translocated hens adapted to the release area. They exhibited similar seasonal movements and used similar habitats as residents. The home range size of resident and translocated hens was comparable; however, previously translocated hens had smaller home ranges than newly released hens.Despite landscape level differences between the source and release areas, translocated hens assimilated to the population and contributed to population growth. Although the translocation was successful, the low vital rate estimates are cause for concern. The low estimates suggest that factors such as predation, habitat quality and quantity, and anthropogenic influences may be problematic for this isolated population.

The Florida Everglades presents a model setting for studying animal-habitat relationships in a dynamic landscape that is heavily influenced by seasonal hydrology and water management. I used dynamic, high-resolution habitat classification maps and radio-telemetry to examine habitat preference of Largemouth Bass, Bowfin, and Florida Gar before and after a field-scale manipulation was established to address uncertainties with Everglades restoration and water management practices. Results indicate preference for the canal habitat by all three species, which represents only a small portion of the submerged landscape even in the driest conditions. Bowfin and Florida Gar were more likely to be relocated within marsh habitats than Largemouth Bass. Preference for the canal habitat increased after landscape alteration and was influenced by water management practices rather than hydrological or environmental factors. Partial canal backfilling may assist with accomplishing restoration goals while maintaining preferred habitat for economically and ecologically valuable predatory fishes.

The Nilgiri tahr (Hemitragus hylocrius) is an endangered mountain ungulate endemic to the Western Ghats in South India. I studied the status and ecology of the Nilgiri tahr in the Mukurthi National Park, from January 1993 to December 1995. To determine the status of this tahr population, I conducted foot surveys, total counts, and a three-day census and estimated that this population contained about 150 tahr. Tahr were more numerous in the north sector than the south sector of the park. Age-specific mortality rates in this population were higher than in other tahr populations. I conducted deterministic computer simulations to determine the persistence of this population. I estimated that under current conditions, this population will persist for 22 years. When the adult mortality was reduced from 0.40 to 0.17, the modeled population persisted for more than 200 years. Tahr used grasslands that were close to cliffs (p <0.0001), far from roads (p <0.0001), far from shola forests (p <0.01), and far from commercial forestry plantations (p <0.001). Based on these criteria I mapped the suitability of tahr habitat using a GIS and estimated that only 20% of the park area had >50% chance of being used by tahr. I used the GIS to simulate several management options to improve the quality of tahr habitat. Suitable habitat for tahr increased two-fold when roads within the park were closed to vehicular access. Similarly, removal of commercial forestry plantations also resulted in a two-fold increase of suitable habitat, and finally when both road access was restricted and commercial forests were removed, suitable tahr habitat increased three-fold. I used micro-histological analysis on tahr fecal pellets to determine food habits. Grasses constituted 64.2% of their diet. Five plant species (Eulalia phaeothrix, Chrysopogon zeylanicus, Ischaemum rugosum, Andropogon sp., and Carex sp.) accounted for 84.6% of the tahr' diet. These species were found in higher densities in the grasslands of the north sector than the south sector of the park (p <0.001). Predators such as leopard (Panthera pardus) and tiger (Panthera tigris), killed and consumed tahr. Tahr constituted 56% of the leopards' diet and 6% of the tigers' diet. I estimated that leopards and tigers in the park killed and consumed 30 to 60 tahr per year, and this accounted for 19% to 38% of the tahr population. The tahr population in the park has undergone a decline, possible causes for this decline includes high mortality from predation and poaching and loss of habitat. / Ph. D.