Climate change poses one of the biggest risks to biodiversity globally. Africa is warming at twice the global average rate and African bird species are therefore at risk, particularly in desert environments where they are already operating near physiological limits. Desert air temperatures in the subtropical latitudes will rise by 3°-5°C by the end of the century. When air temperatures are higher than body temperature, birds must use evaporative cooling to avoid hyperthermia. However, evaporative cooling requires water and a tradeoff exists between hyperthermia and dehydration. For drinking species which need open water sources in order to rehydrate, this tradeoff is exacerbated by high operative temperatures on the ground near the water's edge during periods of extreme heat. This study assessed whether providing artificial shade at waterholes can buffer impacts of high temperature by increasing accessibility of water to birds, potentially facilitating persistence of desert bird communities under climate change. I used a before-after control-impact experimental design to test the impact of shade provision on visitation rates, species richness and the timing of visits by desert birds to waterholes in the Tankwa Karoo National Park of South Africa. Providing shade reduced afternoon waterside operative temperatures below lethal limits for many small passerine species and successfully buffered birds' visitation rates to the water's edge during hot periods, although species richness did not change. Overall bird visitation rates to waterholes increased in the afternoon relative to control sites in response to the addition of shade but decreased in the morning, likely due to a perceived/actual predation risk while operative temperatures were low and shade structures provided no thermal benefit. Responses to shade were species-specific, with the overall positive response driven in part by two common species: Grey-backed Sparrow-larks Eremopterix verticalis and Tractrac Chats Emarginata tractrac. Two species (Cape Sparrows Passer melanurus and White-throated Canaries Crithagra albogularis) responded negatively to the provision of shade. There was an observed shift in bird visitation rates from the morning to the afternoon at shaded structures, suggesting temperature as a primary driver in the use of shade. As temperatures increase under climate change, birds may be forced to drink more in the afternoon due to rising water demands for thermoregulation. Shade structures such as those trialed in this study may have the potential to facilitate this shift and keep water accessible to desert birds in the face of temperature increases.

Vultures are highly mobile scavengers that cover vast distances on their daily foraging trips. Vultures display specific spatial and behavioral patterns when feeding on carcasses, and these behaviors are potentially identifiable in the tracks of geographical positioning system (GPS)- tagged birds. Thus, by applying algorithms to classify their movements it may be possible to create a carcass detection system using these spatial signatures. In this study I applied this approach to explore its efficiency in detecting carcasses and describing the diet of 12 GPStagged vultures in Botswana. I tracked five resident vulture species in Botswana using GPStrackers, these were: Cape Vulture (Gyps coprotheres n=2), Hooded Vulture (Necrosyrtes monachus n=2), Lappet faced Vulture (Torgos tracheliotos n=2), African White-backed Vulture (Gyps africanus n=4) and the White-headed Vulture (Trigonoceps occipitalis n=2). I attempted to search as many as possible of the feeding sites identified by the algorithms between January and June 2022. These potential feeding events were ground-truthed to confirm carcass presence. At each investigated site, any carcass found was identified down to species level. The ground-truthed sites constituted 22% (n=109) of all potential feeding sites identified within the study time frame (n=494). Carcasses were recorded at 62% (n=67) of these investigated sites. Carcasses associated with feeding events from all vulture species were located, except for Hooded Vultures. For this species only one site was checked, with no carcass found. At vulture feeding sites, carcasses from a total of ten taxa were identified. These were mainly wild ungulates (84%) with livestock making up a far lower proportion (16%) comprising of cattle (Bos taurus) and donkey (Equus asinus). Elephant (Loxodanta africana) was the most frequently identified taxon in the carcasses (31%; n=21) and was found at feeding sites of all four vulture species. Although sample sizes were relatively small for each species, it appeared that livestock was recorded only at Lappet-faced and White-backed Vulture investigated sites. Furthermore, Cape and White-headed Vultures had wildlife mostly giraffe and elephant at their investigated sites. Potential feeding events were ground-truthed on average 8 ± 8.35 days after the initial identification of the feeding event. The likelihood of detecting a carcass at these sites declined significantly with the amount of time lapsed from initial identification. The intercept of this relationship suggested that at the time of initial identification there was an 85% chance of detecting a carcass. Vegetation biomass at the sites, and the vulture species involved, had no influence on the likelihood of detecting a carcass. My study, on the application of GPS-tracking to understand the diet of a sample of African vultures in Botswana suggests that this technique is a useful approach but requires substantial resources in terms of personnel to investigate the identified feeding events as soon as these events are triggered, to derive a sufficient sample size to characterize the diets of these different vulture species.

Le bois est un matériau de construction hors du commun; solide, léger et esthétique, il permet la construction de bâtiments sécuritaires et accueillants. De plus, en tant qu’important puit de carbone, il est un excellent outil pour combattre l’accumulation de dioxyde de carbone dans l’atmosphère. Étant de nature biologique et hygroscopique, il est cependant sujet à être dégradé par divers agents biotiques et abiotiques. Parmi ceux-ci, les changements de dimensions, suite à l’adsorption et la désorption d’eau, et la biodégradation limitent beaucoup son usage à l’extérieur des bâtiments. Fort heureusement, la dégradation peut être limitée de plusieurs façons, comme en adoptant des pratiques de construction qui réduisent l’exposition du bois aux sources de dégradation et en utilisant différents traitements. Cette thèse, divisée en trois axes, s’est dédiée au développement d’une barrière pénétrante, un traitement du bois permettant à la fois son imprégnation et son revêtement. Le premier axe s’est concentré sur le développement de la partie pénétrante du traitement et ses performances pratiques. Dans le second axe, la partie pénétrante a été caractérisée de manière plus descriptive pour assurer une protection durable. Finalement, lors du troisième axe, des résines acryliques ont été ajoutées au traitement en guise de partie barrière. Le premier axe a permis de développer une partie pénétrante inspirée du traitement Tru-Core® de la compagnie américaine Kop-Coat et d’évaluer son efficacité sur le pin blanc (Pinus strobus L.) et l’épinette blanche (Piceaglauca (Moench) Voss). Celle-ci utilise des oxydes d’amines tertiaires pour permettre l’imprégnation du bois par diffusion, évitant les procédés classiques nécessitant des cycles de vide et de haute pression. Les oxydes d’amines permettent la solubilisation de fongicides organiques et leur transport dans le bois, améliorant la résistance à la biodégradation du bois traité. Ils réduisent également les changements de dimensions provoqués par les fluctuations d’humidité relative. Le traitement a permis une inhibition presque complète de la dégradation du champignon à pourriture brune Rhodonia placenta, alors que les échantillons témoins ont perdu plus de 22% de leur masse initiale. Des essais de stabilité dimensionnelle ont montré une réduction de 29% des changements de dimensions chez le pin blanc et de 24% dans le cas de l’épinette. Ces résultats se situent loin de ce qui est obtenu par d’autres traitements, comme l’acétylation, qui peuvent atteindre jusqu’à 70%. Ces traitements son tcependant accompagnés de besoins en équipements beaucoup plus sophistiqués, de coûts et de consommations énergiques supérieurs, et d’un gain de masse de plus de 20% du bois traité. Dans le cas de la barrière pénétrante, le gain masse s’est limité à 1-2%. Lors du deuxième axe, des aspects plus techniques et descriptifs du traitement ont été évalués. Bien qu’ils n’affectent pas directement ses performances, ces aspects sont des indicateurs du niveau de protection du traitement. Des essais de profondeur de pénétration, à partir d’une teinture indigo, ont indiqué que les fongicides ne pénètrent que de deux millimètres dans le bois, et seulement longitudinalement. L’indigo a été sélectionnée pour sa structure chimique et sa masse moléculaire, qui sont celles qui se rapprochaient le plus des fongicides utilisés parmi toutes les teintures disponibles. Pour leur part, les oxydes d’amines ont imprégné le bois plus profondément et dans toutes les directions principales. Les fongicides imprégnés ont été quantifiés par chromatographie liquide, indiquant une concentration supérieure à celle suggérée par les normes en matière de protection du bois (minimum 0.040 kg/m3). Même après deux semaines de lessivage par immersion, la concentration des fongicides représentait encore entre 50% et 200% des recommandations des normes, selon l’espèce et le traitement utilisé. Il est donc raisonnable de s’attendre à ce que la protection antifongique reste efficace sur une longue durée. Lors du troisième axe, des résines acryliques commerciales ont été ajoutées à la formulation développée en guise de partie barrière. Plusieurs propriétés des revêtements ont été évaluées, avant et après vieillissement artificiel, en portant une attention particulière sur l’influence de la partie pénétrante sur celles-ci. L’adhérence du revêtement a sensiblement diminué en présence de la partie barrière, tel qu’évalué par des tests d’arrachement. En effet, une rupture à l’interface bois-revêtement était parfois observée à des valeurs inférieures à 2 MPa. La perméabilité à l’eau liquide a environ doublé, mais celle à l’humidité relative n’a pas été affectée. La pénétration de la teinture indigo a légèrement diminué en présence de la résine acrylique, résultat de la viscosité plus élevée des solutions de traitement. / Wood is an outstanding building material; hard, light and aesthetic, it allows the construction of safe and welcoming buildings. Furthermore, as an important carbon sink, it is a great tool to prevent the accumulation of carbon dioxide in the atmosphere. Being biologic and hygroscopic, it is however subject to degradation by diverse biotic and abiotic agents. Amongst those, dimensional changes, following the absorption and desorptionof water, and biodegradation limit its use outdoor. Fortunately, degradation may be limited by adopting building practices which reduce the exposition of wood to the sources of degradation and by using wood treatments. This thesis, divided in three axes, was dedicated to the development of a penetrating barrier, a wood treatment allowing both its impregnation and coating. The first axis was focused on the development of the penetrating part of the treatment and its service performances. During the second axis, the penetrating part was characterized to ensure durable performances. Finally, during the third axis, acrylic resins were added to the treatment as a barrier part. The first axis allowed the development a penetrating part, inspired by the Tru-Core® treatment of the American company Kop-Coat, and the evaluation of its service performances on eastern white pine (Pinus strobus, L.) and white spruce (Picea glauca (Moench) Voss). It used tertiary amine oxides to allow the impregnation of wood through diffusion, avoiding the classic processes relying on vacuum and high pressure. The amine oxides allow the solubilisation of organic fungicides and their transportation into the wood, improving the treated wood’s resistance to biodegradation. They also reduce the dimensional changes induced by the fluctuating relative humidity. The treatment allowed an almost complete inhibition of the degradation from the brown-rot fungi Rhodonia placenta, while untreated samples lost more than 22% of their initial mass. Dimensional stability tests showed 29% less dimensional changes in white pine and 24% in white spruce. These results do not meet the performances of other treatments, like acetylation, which can attain as much as 70%. These treatments however need more sophisticated equipment, are more expensive and energy consuming, and increase the density of the treated wood by more than 20%. With the penetrating barrier, the mass increase is limited to 1-2%. During the second axis, more descriptive and technical aspects of the treatment were evaluated. While they do not directly affect the performances of the treatment, these aspects indicate the level of protection offered by the treatment. Penetration depth tests, performed with an indigo dye, indicated that the fungicides penetrated 2 mm deeps into the wood, and only longitudinally. The amine oxides impregnated deeper than the dye, and in all the principal axes of the wood. The amount of fungicides impregnated was quantified by liquid chromatography, indicating higher concentrations of fungicides than the 0.040 kg/m3 requested by the wood preservation standards. Even after two weeks of leaching through immersion, the concentration was still higher than the recommendations of the standards. For the third axis, commercial acrylic resins were added to the formulation as the barrier part of the treatment. Many properties of the coatings were evaluated, before and after artificial aging, according a particular attention to the influence of the penetrating part on the former. The adhesion of the coatings were substantially reduced, as evaluated with pull-off tests showing fracture at the wood-coating interface at values below 2 MPa. The permeability to liquid water slightly increased, although the permeability to relative humidity was not affected. The penetration of the indigo blue dye was slightly diminished by the acrylic resins, as a result of the increased viscosity of the treatment solutions.

<p> As changing ocean conditions lead to declining fish stocks and movement of forage fish, sea lions on the Oregon coast are subject to the pressures of declining prey availability and increasing conflicts with commercial and recreational fisheries. An analysis of strandings of California sea lions, _{Zalophus californianus,} and Steller sea lions, <i>Eumetopias jubatus, </i> from 2006 to 2014, included cause of death, changing ocean conditions, and anthropogenic activity. Causes of death included disease, injury, and human interaction, such as gunshot wounds, fisheries net entanglements and boat strikes. </p><p> Oregon and Washington strandings of California sea lions are primarily adult and subadult males that migrate north from California rookeries, while Steller sea lions are year-round residents and strandings are comprised of males and females of all ages. While the California sea lion population is currently at or near carrying capacity, the Eastern Pacific population of Steller sea lions was designated as Threatened under the Endangered Species Act until October 2013. Understanding impacts to these two pinniped species is vital to implementing effective management and conservation policies.</p><p> Oregon and southern Washington strandings of California sea lions and Steller sea lions from 2006 to 2014 were analyzed spatially using the geographic information system (GIS), and temporally to identify possible correlations with prey availability and human interaction. Strandings were found to follow seasonal patterns from year to year: Steller sea lion strandings were highest from May to July, California sea lions peaked in September, October, and November. There was a correlation between significantly high numbers of strandings and the three largest commercial fisheries in Oregon: Chinook salmon, Coho salmon, and Dungeness crab. </p><p> This analysis provides a format for continuing to monitor primary ecological and anthropogenic drivers of pinniped mortality in Oregon and southern Washington. </p>

<p> The bog turtle (<i>Glyptemys muhlenbergii</i>) is listed as threatened under the U.S. Endangered Species Act primarily because of the loss and degradation of its specialized wetland habitat. Adequate nesting habitat may be a limiting factor for bog turtle recovery, and nesting habitat creation or expansion may be an effective conservation tool but only if managers understand nesting behaviors, habitat requirements, and threats to nest success. The objective of this study was to understand the nesting ecology of the bog turtle and to use this information to suggest improvements to bog turtle management. I used radio telemetry to locate nesting females. I then used nest location and maternal genetic microsatellite data to investigate nest-site fidelity and natal homing. I collected microhabitat data at each nest and random points in both spring and fall at three spatial scales to understand nest-site selection. I also studied nest success with and without predator excluder cages to determine if predator excluders reduced predation or altered nest conditions. I found evidence that females display nest-site fidelity to nest-site areas but no evidence for natal homing. Bog turtles nested in relatively small patches of habitat in close proximity to water or saturated soil with low densities of woody stems and low percent cover of woody vegetation, forbs, and ferns. Predator excluders reduced predation by &sim;40% while having no effect on nest temperatures, incubation periods, or underlying (disregarding predation) nest success. Given the results of this research, I conclude that the creation of new nesting areas could be a viable conservation tool, as females do not always return to the same nest-site area. Managers should create or maintain small patches of open-canopy habitat with reduced woody vegetation in areas that have consistent moisture from spring to fall. Increasing the availability of nesting areas may eventually lead to increases in recruitment, but if predation pressures are high, managers should also deploy predator excluders. This is the first study to examine the behavioral drivers of bog turtle nest-site selection and the efficacy of predator excluders on bog turtle nests.</p>

No description available.

<p>The translocation of organisms is becoming a frequently used tool in conservation biology. There are, however, a disproportionate number of unsuccessful attempts translocating populations of herpetofauna. Logistical and temporal limits of monitoring, combined with ambiguous metrics concerning &ldquo;success,&rdquo; have led to few advances regarding reptile translocations. Successfully established and persistent populations are those in which both the founding population and subsequent generations show consistent or positive levels of survival and reproduction. A small population of the threatened Florida Sand Skink (<i>Plestiodon reynoldsi</i>) was translocated in 2007. Data collected from 2007 to 2009 confirmed survival and reproduction among the founding individuals, but the sampling did not include a long enough period to allow for the evaluation of the survival and reproduction of individuals born on the site. In this study, individuals were collected during two separate sampling events, one during the third spring and one during the sixth spring after the translocation occurred. Survival estimates, reproduction, population size and generation structure were calculated by combining and analyzing data from all years post-translocation. The numbers of both total and new individuals captured in the sixth year exceeded captures from every prior sampling event since monitoring began in 2008. Founding individuals represented only 14% of the total individuals captured, while the number of individuals born on site continued to increase. The proportion of recruits and increased number of hatchlings despite the loss of founders shows that the filial generations are producing offspring. The methods utilized in assessing this translocation effort will further the understanding of the population dynamics of the Florida Sand Skink and allow for more informed decisions in future management studies of this threatened species. </p>

Thesis (M.S.) in Marine Biology--University of Maine, 2007. / Includes vita. Includes bibliographical references (leaves 34-40).

No description available.

No description available.