<p>The decline of the Oregon Spotted Frog (<i>Rana pretiosa</i>), a Pacific Northwest endemic now federally listed as threatened, has been attributed to several aspects of ecosystem alteration, primarily habitat degradation and loss. The introduced American Bullfrog (<i>Rana (Aquarana) catesbeiana </i>) has been widely implicated in those declines, but the basis of that contention has been difficult to characterize. The bullfrog occurring at every site of recent Oregon Spotted Frog extirpation has focused concern about its impact. </p><p> Here, I present a suite of interconnected studies that examine the behavioral ecology of both species to better understand the potential for bullfrog-mediated Oregon Spotted Frog extirpation. I quantified Oregon Spotted Frog anti-predator behavior from the only known population successfully co-occurring with bullfrogs (Conboy Lake) and a population devoid of bullfrog impact (Big Marsh), and compared these behaviors to the predatory traits of the bullfrog. The initial study revealed that captive-reared individuals from the Oregon Spotted Frog population that has successfully co-occurred with bullfrogs respond faster to a predatory stimulus (measured as latency to response) than Oregon Spotted Frogs from a population not to exposed to bullfrogs. Subsequent field investigations of the approach distance allowed by a predator stimulus before taking evasive action (termed the flight initiation distance: FID) conducted with the Oregon Spotted Frog population co-occurring with bullfrogs first demonstrated that FID of recently metamorphosed bullfrogs is consistently greater than that of recently metamorphosed Oregon Spotted Frogs. Further, examination of FID across all post-metamorphic age classes of Oregon Spotted Frogs revealed that older frogs do not allow as close approach as recently metamorphosed Oregon Spotted Frogs. This age class shift in FID did not occur in the Oregon Spotted Frog population not exposed to bullfrogs. In the latter population, FID did not differ among age classes. </p><p> Since the bullfrog might be driving this age-based change in anti-predator behavior, I explored the variation in strike distance of bullfrogs from the site of co-occurrence in both the field and laboratory to determine the extent of overlap with Oregon Spotted Frog FID. I found that the bullfrog strike distance significantly overlaps the FID of all ages of Oregon Spotted Frogs from the bullfrog-free site but only that of youngest (recently metamorphosed) frogs at the site of co-occurrence. Older Oregon Spotted Frogs from the site of co-occurrence generally escaped at distances greater than the strike distance of bullfrogs. </p><p> I also collected > 880 bullfrogs from the site of co-occurrence and analyzed the stomach contents to assess their dietary trends. I found that bullfrogs consume Oregon Spotted Frogs at the site, but do not eat the larger (older) frogs. Moreover, the body size ratio between Oregon Spotted Frogs as prey and bullfrogs as predators suggests that nearly all of the adult size distribution of bullfrogs at Conboy would be incapable of preying on adult Oregon Spotted Frogs. </p><p> Collectively, these studies strongly suggest that bullfrogs have altered the escape behavior of Oregon Spotted Frogs at Conboy Lake and that most adult Oregon Spotted Frogs at Conboy may have a size-based release from predation by bullfrogs. Implicit in this finding is that bullfrogs may pose a real threat via predation to other Oregon Spotted Frog populations with which they might come into contact where the distribution of bullfrog body sizes differ substantially from that at Conboy Lake. </p>

<p> Minimizing inbreeding depression and maintaining genetic diversity are central goals of conservation programs, including the Greenback Recovery Program (GRP), an interagency effort to protect the lineage of trout native to the South Platte River drainage in Colorado. The last remaining population of greenback cutthroat trout consists of about 700 individuals found in a three-mile stretch of stream in the Arkansas drainage, outside its native range. The GRP is committed to reintroducing the greenback into its native range in the South Platte. To do so, they are using a hatchery stock founded by 46 wild individuals. Both wild and hatchery populations have limited genetic diversity and deformities are common in the hatchery population. </p><p> Recovering the fitness of the hatchery population of greenbacks requires variation in fitness upon which selection can act. I performed crosses between individuals to quantify any remaining variation in fitness. The population had high variation in egg production and fertilization but very little variation in overall offspring survival. This suggests that the hatchery managers should consider alternative sources of genetic diversity, such as individuals from the wild or from other subspecies.</p><p> I used a crossing experiment between greenback cutthroat trout and a related subspecies to describe the genomic patterns of recovery of fitness. When greenbacks are crossed with another subspecies, the hybrid offspring have much higher fitness than the pure greenback offspring. I found that the probability of survival has a strong genetic component and that relatedness between the parents is a strong predictor of offspring survival, with offspring from less related greenback parents having higher fitness. This research will help managers decide whether outcrossing is a viable strategy to increase genetic diversity in cutthroat trout.</p><p> I explored the barriers to implementing evolutionary restoration tools, which include a reluctance to disrupt the taxonomic integrity of species. Evolutionary restoration is analogous to ecological restoration: both fields face the challenge of choosing appropriate restoration baselines and setting realistic restoration goals. Active interventions to increase gene flow should be considered as a complement to habitat protection and ecological restoration to prevent species decline.</p><p> I developed a teaching case study based on cutthroat trout research. The case study gives upper division biology students practice in applying evolutionary concepts to a real-world conservation problem by making evidence-based decisions accounting for uncertainty in real data sets. I used the case of cutthroat trout in Colorado because it requires a fundamental understanding of evolutionary processes such as speciation and hybridization and raises questions about the value of native species and the goals of conservation efforts.</p>

<p> Multiple ecological factors (e.g., Bergmann&rsquo;s rule, competition, food quality and quantity) can be responsible for changes in animal body size over time. White-tailed deer <i>(Odocoileus virginianus)</i> serve as an ideal candidate for studying these variables due to their importance today (to hunters and to wildlife enthusiasts), their known phenotypic plasticity in response to ecological factors, and their high frequency in zooarchaeological collections. Using post-cranial, weight-bearing bone measurements as a proxy for body size, this study determines that stunting occurred from prehistoric to modern times in Missouri white-tailed deer. Forage availability and intraspecific competition were the major influences on body size. A diminution event occurred ~1600&ndash;1300 radiocarbon years B.P. and is associated with fluctuating climatic conditions at the time. Modern deer in Missouri are smaller relative to an early prehistoric (ca. 3500 &ndash; 1300 B.P.) sample but smaller than a late prehistoric (ca. 1300 &ndash; 200 B.P.) sample. The historic diminution event seems to stem from modern management goals favoring large population sizes. Advantages of incorporating paleozoological data with modern conservation biology are exemplified by this study.</p>

<p> This thesis looks at how ecotourists can become aware of biocultural diversity (the intersection of biological and cultural diversity) and help contribute to sustainable development, which considers the needs of both present and future generations. The thesis will address the ecotourism industry and how people who travel with companies that cater to ecotourists can contribute to biocultural diversity and sustainable development. It will utilize a sustainable development framework and a critical theory approach for considering biological and cultural perspectives including human rights and social justice, the contribution of traditional knowledge, community involvement, and the effects of human impact and globalization. The primary audience of my research is people who travel the globe in search of the earth&rsquo;s natural wonders. I highlight issues related to minimizing environmental impact, respecting local cultures, building environmental awareness, and providing direct financial benefits for conservation. My central research question is: <i>How can travelers help to preserve the environment, be sensitive to local cultures, and contribute to a sustainable future?</i> I ask: <i>By understanding the distinct correlation between biological and cultural diversity, how can we utilize both traditional (and local) knowledge combined with scientific knowledge to help sustain and preserve our natural ecosystems?</i></p><p> I conclude with findings that point to the need for shared community authority, management, and decision making; mutual benefits; recognition of the rights, values, norms, power structures, and dynamics of local populations; respect for belief systems as well as traditional and local ecological knowledge; and the importance of contextual adaptation.</p>

No description available.

The declining area of heathland in north-west Europe is causing widespread concern amongst conservationists. The aim of the experiments described in this thesis was to investigate methods of heath creation by establishing the dwarf shrub, <I>Calluna vulgaris</I> (L.) Hull, on the ex-arable land. Arable land, surplus to requirement and available through set-aside schemes, could be used to expand or join together small pockets of remnant heath. Field experiments were designed to test various methods of introducing <I>Calluna</I>, but, in all cases, it failed to persist and spread after introduction. The most promising method of introduction was to transplant young plants. The conditions at the field site, in arable production immediately prior to the experiments being set up, were such that <I>Calluna</I> was unable to establish dominance. High residual soil fertility combined with a large weed seed bank produced a dense cover of vegetation in which <I>Calluna</I> did not persist. Pot experiments were carried out to determine whether soil amendments might make the creation of heath more feasible on ex-arable sites. Most amendments reduced the dry matter production of the weed species tested compared to the control treatment (un-amended field soil). One treatment, elemental sulphur, significantly reduced the growth of a major weed species (<I>Trifolium repens</I>) at very low application rates, whilst <I>Calluna</I> grew well on the amended soil. Elemental sulphur lowers soil pH and therefore reduces the availability of most plant nutrients and increases the solubility of some metals. When tested in the field, high rates of sulphur significantly increased the survival of <I>Calluna</I> transplants. The author suggests that soil modification with an acidifying agent is the key to heath creation on agriculturally-improved soils. Vegetation management, such as the use of herbicides may also have a part to play, although once soil conditions are suitable this management would be reduced very much to a secondary role.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

<p> Survival of the endangered Light-footed Ridgway&rsquo;s Rail (Rallus obsoletus levipes) depends on marsh conservation and restoration efforts that supply suitable nesting habitat. Previous research indicates that rails preferentially nest in low marsh areas with tall, dense Spartina foliosa (Pacific cordgrass). While canopy architecture (e.g. height and density) is important, additional microhabitat and landscape-level metrics may be involved in nest-site selection. This project characterized microhabitat parameters (e.g. vegetation and food availability) and landscape-level parameters (e.g. spatial configuration) for 40 nests and 40 non-nest sites in two California wetlands, Upper Newport Bay and the Tijuana Slough, to identify habitat features that predict reproductive success. Assessment of the microhabitat and landscape-level parameters suggests that vegetation structure (e.g. height, stem density) is important, but that invertebrate density and composition, tidal connectivity, and elevation are also important to Light-footed Ridgway&rsquo;s Rail nesting.</p>

<p> The white-tipped dove (<i>Leptotila verreauxi</i>) is a sedentary, secretive columbid that ranges from Argentina to the Lower Rio Grande Valley (LRGV) of south Texas. Since its designation as a game species in 1984, little research has been dedicated to the species&rsquo; reproductive ecology. My objectives were to (1) identify predators of white-tipped dove eggs and nestling, (2) determine how the predator community differs among land cover types, (3) examine the impact of vegetation and landscape variation in both citrus and woodland land cover types on nest survival, (4) examine the impact of temporal variation on nest survival, (5) provide information on general nest ecology that is currently lacking, (6) investigate movements of doves and examine feasibility of tracking and recapture using a GPS/VHF transmitters pilot study. During the summers of 2015 and 2016, I conducted nest searches in citrus and woodland sites in Hidalgo County, Texas. I placed real-time, infrared emitting camera systems on a subset of nests to monitor predation. I also trapped, banded, and placed backpack transmitters on doves in Estero Llano Grande State Park (ELGSP) In the 2 years, I located 63 dove nests, 34 in citrus and 29 in woodland. I placed camera systems on 33 nests and identified 9 species of nest predator. Green jays (<i>Cyanocorax incas</i>) were our most common nest predator, accounting for 10 of 28 predation events. Other predators were crested caracara (<i>Caracara cheriway</i>), Harris&rsquo;s hawk (<i>Parabuteo unicinctus</i>), great-tailed grackle (<i>Quisicalus mexicanus</i>), tawny crazy ant (<i> Nylanderia fulva</i>), rat (<i>Rattus</i> spp.), opossum (<i> Didelphis virginiana</i>), house cat (<i>Felis catus</i>), and Texas indigo snake (<i>Drymarchon melanurus erebennus</i>). Based on AIC candidate model selection, I identified nest stage as the best predictor of daily nest survival rate across both land cover types. By separating land covers for a second step to model selection, I identified different environmental variables as predictors of daily survival rate in each land cover type. In the woodland site, my null model was most important, indicating that no measured variables were important for predicting nest survival. In citrus, canopy cover was the top model. In citrus, a diverse predator community due to heavy human disturbance may have increased the importance of canopy cover and other concealment variables for nest survival. The different predator communities they encounter in the two land cover types that they nest in prioritize much different environmental conditions for nest survival.</p>

Master of Science - Science / Relationships between symmetries and conservation laws of perturbed partial differential equations are reviewed. Potential symmetries and their applications to perturbed partial differential equations and conservation laws are presented in detail. An example of a perturbed wave equation for an inhomogeneous medium is solved in detail. Proofs of some of the lesser-known theorems are outlined. A wide range of examples is given to further explain these concepts.