<p> This thesis examined avian population dynamics over a four year span (2011-2014) in four forest types in Kings Canyon, Sequoia, and Yosemite National Parks, California. I asked, do bird populations show fluctuations in abundance and species richness depending on early spring snowpack levels in various forest types of the Sierra Nevada? I conducted point transect sampling surveys as part of the Sierra Nevada Network's Inventory and Monitoring bird monitoring program. To calculate local abundances for fourteen common bird species, I modeled detection functions in program Distance 6.2. I also determined species richness for each transect, and finally correlated avian abundance with spring snow depths. None of the common bird species in this study displayed a strong correlation between their abundance and snow depths in any of the four years. Clark&rsquo;s Nutcracker indicated potential for a positive correlation for abundance and snow depth, but this result may have been driven by other factors. With changing climate in the Sierra Nevada expected to increase the variability of snowpack among years, it is crucial to continue studying relationships between bird populations and snowfall in the Sierra Nevada.</p>

<p> This project aims to develop a panel of sequence capture baits to use for SNP genotyping for pedigree analysis in Wood Ducks (<i>Aix sponsa </i>) as well as for general population genetic analysis within species in the family Anatidae. SbfI RAD libraries were prepared with samples comprising five duck species (N = 96). Sequenced libraries were aligned to the Mallard (<i>Anas platyrhynchos</i>) reference genome and screened for 120bp regions proximal to the SbfI cutsite that contained SNPs conserved collectively in each species. A series of screenings identified regions which were used to produce 2,508 custom sequence capture baits. These baits were tested in novel individuals from the same species used to design the baits as well as novel species representing different taxonomic ingroup and outgroup levels within Aves. These baits delineate species at various taxonomic scales, even above the taxonomic level that was originally targeted and will prove useful for analyses of population and comparative genetics for species of Anatidae and perhaps more broadly.</p><p>

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: John Byrne, School of Urban Affairs & Public Policy. Includes bibliographical references.

Thesis (M.E.S.)--York University, 1999. Graduate Programme in Environmental Studies. / Typescript. Includes bibliographical references (leaves 78-84). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ44669.

<p> Terrestrial litterfall is a well-documented subsidy of nutrients and organic matter to adjacent aquatic ecosystems. Nitrogen-fixing plants increase nutrient dynamics via nitrogen (N) - rich litterfall in both terrestrial and aquatic ecosystems, and the effects are often more pronounced when areas lacking native N₂-fixers are invaded. This study examined differences in organic matter and nutrient inputs from the invasive, N₂-fixing tree, <i>Prosopis pallida</i>, and the native, non N₂-fixing tree, <i>Thespesia populnea</i>, to determine effects on anchialine ponds on Hawai`i Island's leeward coast. My objectives were to quantify: 1) tree basal area and density surrounding the ponds, 2) quality and quantity of <i>P. pallida</i> and <i>T. populnea</i> litter inputs, 3) inorganic N content of soil surrounding the ponds, 4) leached nutrients from <i>P. pallida</i> and <i>T. populnea</i> leaf litter. These response variables were then compared to water nutrient concentrations (i.e., phosphate, nitrate, ammonium, dissolved organic carbon (C), and total dissolved N and phosphorus (P)) in the ponds of interest. Basal area, density, litterfall mass, total N and C inputs, and leachate values were similar between pond types categorized as <i>P. pallida</i> &ndash; or <i> T. populnea</i> &ndash; dominated. Foliar N concentrations were 28 percent higher in <i>P. pallida</i> &ndash; dominated ponds compared to <i>T. populnea</i> &ndash; dominated ponds, but foliar P concentrations were three times greater in <i>T. populnea</i> ponds than <i>P. pallida</i> ponds. Total P inputs were greater beneath <i>T. populnea</i> ponds and there was a positive correlation between <i>T. populnea</i> size and abundance and pond water phosphate concentrations. These results suggest that the N if influencing water quality in Hawaiian anchialine ponds more than the invasive N₂-fixing species, although high background water nutrient levels may be inhibiting our ability to detect any significant impacts. The transfer of <i>T. populnea</i>'s P-rich litter to pond water appears to have a strong influence on ecosystem functioning.</p>

Includes bibliographical references / Eastern high - altitude grasslands of South Africa are centres for endemism and harbour fauna and flora of regional and international conservation concern. This area also provides important ecological services such as provision of water to communities downstream. Sweet and sour veld support beef livestock farming during summer months. The aesthetic beauty of the region makes the area a prime tourist destination too. More recently the area is becoming a target of other agricultural projects such man - made forests. Other new developments that need to be mitigated against are development of renewable energy projects such as pumped water schemes to generate electricity or wind farms. Additional habitat is lost when these projects are connected to the national grid. In this thesis, I use bird data and vegetation data to compare, contrast and suggest management tools to manage this area. I present data that I collected at Ingula Pumped Storage Scheme spanning five years from the beginning of the construction of the scheme to near its completion in 2012 as a case study to manage similar habitats. Chapter 1 presents a brief overview of ecological importance of this area and the history behind the construction of pumped storage scheme at Ingula. A literature review in Chapter 2 investigates management tools to manage these grasslands for avian diversity. Fire and grazing is a key management tool cited to make habitat suitable for birds. While few studies from this type of grassland exist, studies from outside South Africa suggest that fire and grazing supplement each other as management tool to make habitat suitable for species with contrasting ecological requirements. A mosaic of grass heights and cover across the landscape translates to species habitat suitability. Chapter 3 explores species richness through years, seasons and impact of grass height and cover on bird species richness. Species richness was highest in summer suggesting that management should make habitat for species suitable in summer when most priority species are likely to use the habitat. The main disadvantage of using bird species richness is that fieldworkers must know their species well. Secondly, use of species richness must be treated with caution because this method does not account for species detectability in time and in space. In Chapter 4 I use hierarchical distance sampling models which take into account both the detection and the biological process. To demonstrate this I used common grassland bird species which can easily be identified during monitoring. The downside of this approach is that because these species are common and therefore occur almost everywhere, they may not easily respond to lack of habitat heterogeneity. The technical disadvantage of using this method is to accurately allocate species to within distance bands, making this method challenging for fieldworkers. Chapter 5 presents random plot occupancy which records only detection - nondetection of birds during repeated plot surveys. This method accounts for observational and biological processes too and in addition implements rigorous statistical inferences to predict how birds respond to habitat variable s as influenced by management decision on fire and grazing. Finally, adverse weather conditions may hamper surveying all plots in some years. Through occupancy modelling it is possible to predict species occupancy on plots that were not surveyed during some years and finally this method has been improved to include rare species. This is my preferred method to monitor management effect on habitat suitability for birds at Ingula. Adaptive management, a pillar of which is adaptive monitoring is a new paradigm shift in conservation. In Chapter 6, I capture interactions between burning and grazing and effects on grass height and cover to predict habitat suitability for birds including large threatened Ingula birds using a simulation models. This model sets a stage for implementing adaptive management through experimental plots to capture a set of management uncertainties regarding the use of fire and grazing as management tools. Chapter 7 summarizes the thesis and acknowledges that Ingula consists of other equally important habitat and ecosystem such as cool moist mountain forest and matrix of grassland wetland that equally need to be conserved.

Thesis (M. Phil.)--University of Hong Kong, 1977.

Thesis (M. Sc.)--Université Laval, 2002. / "Fevrier 2002." Includes bibliographical references. Downloaded and printed from Laval University website.

It is estimated that 10-15% of the worlds blanket bog occurs in British uplands, although this is at risk due to land-use change, climate change and tourism. Currently, several types of management and restoration work are underway in many upland areas to prevent further degradation (RSPB, 2007). Within the RSPB Vyrnwy reserve a five year management plan is currently in progress. The area contains numerous drainage ditches created to improve the quality of grazing. This has lead to a loss of blanket bog vegetation, as the drains facilitate the removal of water, across the site (Worrall, et al, 2007). To encourage the reformation of blanket bogs these ditches are now being dammed. Approximately 4500 ha will be treated over the five year period, with an estimated 18km of drains blocked each year. Previous studies suggest this will lead to increases in CH4 flux from peatlands (Price, 1997). CH4 flux rates at difference water tables in Calluna and Eriophorum cores from Lake Vyrnwy were measured in a controlled environment. It was concluded that, in the short term, water table manipulation does influence net CH4 flux rates in peat cores from this system. In Eriophorum cores a positive flux was recorded at the high water table but not where the water table was 10cm lower. A 13C-CH4 approach was also applied to more accurately determine CH4 oxidation rates. These results indicated CH4 oxidation was occurring at all water tables and in both vegetation types, even when a positive net flux was seen. It was established that comparing both 12+13C-CH4 flux rates, and 13C-CH4 oxidation rates provided more information on the impacts of water table manipulation than relying on flux data alone. Data presented suggests that gripping at Lake Vyrnwy has the potential to decrease rates of CH4 oxidation across the site.

<p> While the processes that led to the formation of modern plant communities are often cryptic, biogeographic patterns of extant species can provide clues to their origin. The Midriff Islands, an archipelago in the Gulf of California at the center of the Sonoran Desert, provide an opportunity to investigate the origins of the desert. This research uses three case studies at three different time scales to better understand the factors responsible for modern biodiversity. </p><p> Chapter 1 revisits the theory of island biogeography and incorporates the long history of humans on the Midriff Islands to determine factors controlling plant species richness. Area, habitat diversity, island type, and seabird dynamics explain 98% of the variability in species richness across this archipelago. Interestingly, human presence is not predictive, suggesting an island system with ancient human interactions that functions in a pre-Anthropocene state. </p><p> Chapter 2 investigates Holocene extinctions. In 1975, bighorn sheep (<i> Ovis canadensis</i>) were introduced as a novel element to Isla Tibur&oacute;n as a conservation measure. Fossil dung found on Isla Tibur&oacute;n was 14C-dated to 1476-1632 years before present and identified as <i>Ovis canadensis </i> by morphological and ancient DNA analysis. Bighorn sheep went locally extinct on the island sometime in the last ~1500 years prior to their "unintentional rewilding." This discovery questions the definition of a non-native species and extends an ecological and conservation baseline. </p><p> Disjunct long-lived plant taxa on Isla Tibur&oacute;n suggests climate and vegetation change on the Midriff Islands in the Pleistocene. Chapter 3 is a phylogeographic study of the desert edge species <i>Canotia holacantha </i> (Celastraceae) that tests whether <i>Canotia</i> on Isla Tibur&oacute;n is a Pleistocene relict or a recent dispersal event. Results suggest long isolation and divergence of <i>Canotia</i> on Tibur&oacute;n but recent arrival in the core of its modern day distribution in Arizona. In contradiction to an expected temperate origin, <i>Canotia</i> seems to have tracked the northward shift of the desert's edge at the end of the last Ice Age from glacial refugia in Sonora or Chihuahua. </p><p> Collectively, this research helps illuminate the history of the desert and establishes baselines to support management decisions of the world's best-preserved archipelago.</p>