Thesis (Ph.D.)--Drexel University, 2010. / Includes abstract and vita. Includes bibliographical references (leaves 206-237).

The persistence of woody plant populations faces numerous environmental challenges, including climate change, hybridisation and population fragmentation. Here I explore the genomic signatures and relative importance of these pressures in Dwarf Birch (Betula nana), which has declined significantly over the last century across the Scottish Highlands. Firstly, I find that future climate is likely to result in a significant range reduction and that relict populations are likely to display reduced fitness. Secondly, I show that combining multiple mutation rate markers yields more accurate estimates of demographic history and the impact of fragmentation. I develop a novel method to derive high mutation rate markers from short sequencing reads, to facilitate more widespread application. Thirdly, I assess the degree of local adaptation, and explore potential for composite provenancing for the restoration of B. nana populations. Surprisingly, the data yields little evidence of adaptive introgression from the related tree B. pubescens, suggesting that this may not be an alternative route to climate tolerance. Finally, I review published literature on the population structure and genetic diversity of genus Betula in Europe and consider options for the conservation and management of B. nana, including assisted gene flow and prioritization of in situ genetic diversity.

<p> Climate change and over-use of natural resources impacts ecosystems worldwide. Understanding physical impacts from climate and natural resource use on biological processes at multiple scales of spatial and ecological organization is needed to make useful predictions under global change scenarios. Mountain aquatic ecosystems are of particular concern because they are sensitive to climate change, represent hot spots of biodiversity, and they integrate atmospheric, terrestrial and aquatic processes into biological responses. The objective of this dissertation is to quantify physical impacts and biological responses of climate and water use on mountain aquatic ecosystems in the Western United States. In Chapter 1, I developed a data set of ice break-up dates using remote sensing techniques for mountain lakes across the Sierra and Cascade Mountain Ranges coupled with downscaled climate data to quantify drivers of lake ice phenology. I developed a predictive linear mixed effects model and used and ensemble of 15 global climate models to project changes in lake ice break-up dates through the 21^st century. The results suggest that low snowpack and increased energy fluxes associated with elevated air temperatures drive earlier ice break-up dates. Projections of ice break-up show that ice break-up will be 61 &plusmn; 5 days if greenhouse gas emissions are not reduced. In Chapter 2, I analyzed specific ecological responses to earlier ice break-up dates in Castle Lake, California (a natural, sub-alpine lake). I predicted that consumer (Brook Trout; <i>Salvelinus fontinalis</i>) energetics and habitat use would be regulated by either climate driven water temperature or variation in food availability. The data suggest that earlier ice break-up results in a longer duration of surface water temperatures > 15 &deg;C, coupled with decreased and increased food production in the pelagic and littoral zones, respectively. Isotopic and telemetry data showed that consumer resources and habitat use were driven by water temperature and were independent of food availability. In early ice break-up years, consumers grew less because they were thermally excluded from productive littoral zones when water temperatures were warmer for longer periods of time relative to late ice break-up years. In Chapter 3, I demonstrate that decreased streamflow in mountain rivers can reduce abundance and size structure of food supply to drift foraging Rainbow Trout <i>(Onchorhynchus mykiss)</i>. In response to changes in streamflow and food availability, trout abandoned their energetically profitable drift foraging strategy and actively searched for prey. The shift in foraging behavior resulted in negative bioenergetic efficiencies in flow impaired sites. Taken collectively this research demonstrates that both predictable and unpredictable consequences of physical change drive biological responses across spatial gradients, ecosystem types, and levels of ecological organization.</p><p>

<p> The Brownsberg Nature Park (BNP) in Suriname is home to eight monkey species: <i>Saguinus midas, Saimiri sciureus, Cebus apella, Alouatta seniculus. Pithecia pithecia, Cebus olivaceus, Chiropotes satanas (sagulatus), </i>and <i>Ateles paniscus.</i> Several studies have undertaken the task to better study the feeding and behavioral ecology of these species within the park. However, studies on the black spider monkey (<i>Ateles paniscus</i>) have been absent. As part of my thesis, I decided to conduct a baseline feeding and behavioral ecology study of this species during the period May 2008 &ndash; July 2008. In addition, I developed a field method for determining mercury levels (in parts per million = ppm) in fecal and urine samples of wild monkeys. Since the park is under enormous pressure from illegal gold mining activities, I decided to collect baseline data on potential exposure of wild monkeys to mercury in the environment. I also collected samples from monkeys at the zoo in Paramaribo and monkeys born in captivity at Hiram College in Ohio. I collected data on the frequency of feeding, resting, and traveling by black spider monkey subgroups every 10 minutes during all day follows. Feeding ecology data consisted of identifying fruits eaten by these subgroups. For the mercury analysis I used the OSUMEX LTD. home testing kit. Results from the behavioral data show the following frequencies of activities for the entire study period: 32% feeding, 43% resting, and 25% traveling. The feeding data further justifies spider monkeys as ripe fruit frugivores: 76% of food items consisted of ripe fruit, while 22% consisted of leaves, and 2% was comprised of flowers. The mercury testing results from the Brownsberg and zoo populations ranged between 0.025 ppm to 0.1 ppm (toxic level = 0.8 ppm). The Hiram College monkeys all displayed levels at 0.000 ppm. The results from the mercury analyses indicate that 1) wild monkeys in the vicinity of gold mining activities may not be under the same threat as humans, with regards to mercury exposure through food, and 2) that wild monkeys are still relative exposed to mercury in the environment whether it be natural or anthropogenic.</p>

Les cadres théoriques de la conservation de la nature n’ont pas un caractère figé, mais ont évolué au cours du temps en privilégiant telles ou telles valeurs, notamment intrinsèques ou instrumentales. Or, les limites de ces cadres d’analyse pour susciter des engagements pour la nature ont été montrées. En m’appuyant sur la notion de valeurs relationnelles ainsi que sur celle des transformations des expériences de nature, j’ai conduit un travail qui veut apporter une réflexion complémentaire aux manières de concevoir la conservation de la nature. Pour cela, à travers l’étude transdisciplinaire des initiatives citoyennes de jardins partagés, cette thèse cherche à comprendre les motivations des citoyens ordinaires à s’engager pour la nature. Ce travail a notamment permis de montrer que des expériences de nature se font aussi en ville, par exemple pour combler un vide personnel par des pratiques de jardinage et des mises en relations sociales et écologiques dans ces espaces. Ces expériences sont aussi vécues par les riverains des jardins, qui pour la plupart reconnaissent et valorisent les bienfaits de ces jardins pour eux, pour les jardiniers, pour le quartier et pour la ville. Au niveau de la biodiversité, j’ai montré que les jardins sont des endroits propices pour l’installation d’une flore spontanée, dont la richesse dépend de l’action des jardiniers et des décisions des propriétaires du terrain (notamment de laisser l’espace disponible sur un temps long). Enfin, j’ai montré comment les relations socio-écologiques créées et encouragées dans un jardin deviennent des moteurs pour l’action politique. Par tous ces angles d’approche, ce travail de thèse montre donc le rôle crucial des valeurs relationnelles dans la motivation à conserver la nature. Relations à reconnaitre et valoriser dans toutes leurs diversités. / Theoretical frameworks for nature conservation have evolved through time, with priority successively given to different values, instrumental or intrinsic. However, these frameworks have limits in motivating engagement towards nature. Building on the respective notions of relational values and transformation of nature experiences, my thesis work aims to fuel the reflection on new ways of considering nature conservation. I have used community gardens, a particular form of citizen initiative, as a study case to understand the motivations of ordinary citizens to engage towards nature. On the social side, I showed that experiences of nature can be gained in these gardens despite the urban environment, to fulfil personal needs through gardening and through the development of social and ecological relationships. These experiences of nature influence the neighbouring citizens of the gardens, who acknowledge their benefits for themselves, the gardeners, the neighbourhood, and the city in general.On the ecological side, I showed that community gardens host a rich community of spontaneous plants, which species richness depends upon gardeners’ management and garden age, which in turn depends on stakeholder decisions as to the durability of community gardens.Last, I showed how socio-ecological relationships created and promoted in a community garden can become drivers for political actions, through the particular case of one garden.Through this combination of social and ecological approaches, this thesis highlights the crucial role played by relational values in nature conservation motivation. These relations have to be acknowledged and promoted in all their diversity.