Sumatran elephant (Elephas maximus sumatranus) populations continue to decline due to habitat loss, poaching and conflict with humans. In Sumatra, elephant populations are fragmented into small isolated populations and increasingly cause conflict with humans. Yet, habitat loss due to the rapid land conversion for development is continuing an alarming situation. Developing effective land conservation strategies for elephants is difficult because there is little information available on foraging ecology, habitat use, movements and home range behaviors. I conducted a study on these topics in Seblat, Bengkulu Province, Sumatra during 2007-2008. The five important families of plants in the elephant diet in Sumatra ar: Moraceae, Arecaceae, Fabaceae, Poaceae,and Euphorbiacea. Elephants in Seblat tend to browse more than graze and elephants tend to browse more during the wet season. The nutritional quality (Crude Protein, Calcium, Phosphorus and Gross Energy) of elephant diet in Seblat is suitable to support population reproduction and growth. Home range size of one telemetered 97.4 km2 for the MCP and 95.0 km2 for the 95% fixed kernel. There was no relation between average monthly elephant home range sizes and rainfall, nor any correlation between monthly elephant movement distances and rainfall. Vegetation productivity, as measured by the Enhanced Vegetation Index (EVI), was probably the factor most affecting elephant movements compared to the distances to rivers and ex-logging roads on the SECC. Resource selection analyzes indicate that elephants in Seblat seem to select medium canopy and open canopy areas more than expected. Similarly, habitat ranking using compositional analysis shows that in 2nd order and 3rd order selection, medium canopy and open canopy were the two habitat types with a greater level of used. Habitat use based on diurnal and nocturnal elephant activities indicates that elephants preferred closed canopy habitat compare to the open canopy habitat during the day. The results of this study suggest wide conservation implications for elephants on Sumatra, helping to guide effective land use conservation programs and provide scientific guideline to restore disturbed habitat and select priority areas for Sumatran elephants.

No description available.

Honey bees, Apis mellifera Linn., provide vital economic and ecological services via pollination while concurrently facing multiple interconnected stressors impacting their health. Many crops like apples, peaches, and cherries that add diversity and nutrition to our diet are wholly or partially dependent upon the pollination services of insects. Orchard crops are self-incompatible and commonly regarded as crops reliant on the pollination services of insects, and while previous studies have focused on the impact of bees to orchard crops during bloom, fewer studies have examined the reciprocal relationship of the orchards on honey bees, particularly across the entire foraging season. Here we investigated the foraging dynamics of honey bees in an orchard crop environment in Northern Virginia, United States. We decoded, mapped, and analyzed 3,710 waggle dances, which communicate the location of a valuable resource in the environment, for two full foraging seasons (April-October, 2018-2019), and, concurrent to the dance filming, collected pollen from returning foragers. We found that bees forage locally the majority of the time (< 2 km) throughout the season, with some long-range distances occurring in May after bloom (both 2018 and 2019) and in fall (2019). The shortest communicated median distances (0.50 km and 0.53 km), indicating abundant food availability, occurred during September in both years, paralleling the bloom of an important late season resource, goldenrod (Solidago). We determined, through plotting and analyzing the communicated forage locations and from the collected pollen from returning foragers, that honey bees forage more within apple orchards after the bloom (29.4% and 28.5% foraging) compared to during bloom (18.6% and 21.4% foraging) on the understory of clover and plantain. This post bloom foraging also exposes honey bees to the highest concentration of pesticides across the entire foraging season (2322.89 ppb pesticides versus 181.8 during bloom, 569.84 in late summer, and 246.24 in fall). Therefore, post bloom apple orchards supply an abundance of forage, but also the highest risk of pesticide exposure, which may have important implications for management decisions of bees in orchards. / Master of Science in Life Sciences / Honey bee hives have been declining significantly in the United States, driven by a multitude of issues and stressors including pesticide exposure, disease, pests such as varroa mites, and poor nutrition caused by natural land being converted into development or agriculture. Agricultural landscapes, in particular, are often monocultures are saturated with pesticides creating a potentially hazardous environment, yet reliant on bees to provide pollination for crops. Because of this interconnected relationship between bees and flowers and the effects of stressors agricultural systems cause have with pollinators, it is necessary to understand how honey bees forage in these environments and what potential health risks they face. We investigated honey bees foraging dynamics in an apple orchard in Northern Virginia, United States by observing honey bee waggle dance behavior, where bees literally waggle back and forth for a certain time and at a certain angle telling their nestmates where a resource is, and collecting pollen from returning forager bees to better understand when, where, and upon what honey bees forage throughout the foraging season, which is when flowers are available and the weather warm enough (April – October). We found that bees mostly forage locally near the hive throughout the season, indicating that sufficient amount of food was available even after short bloom time of the apple (April to mid-May). We determined, through plotting and analyzing the waggle dance locations, that honey bees forage more within apple orchards after the bloom on mostly clover and plantain. This abundance of post bloom foraging also exposes honey bees to the highest amounts of pesticides across the entire foraging season. Post bloom apple orchards supply an abundance of forage, but also the highest risk of pesticide exposure to honey bees.

Resource variation and species interactions require organisms to respond behaviorally, physiologically, and morphologically within and among generations to compensate for spatial and temporal environmental variation. One successful evolutionary strategy to mitigate environmental variation is phenotypic plasticity: the production of alternative phenotypes in response to environmental variation. Phenotypic plasticity yields multiple characters that may enable organisms to better optimize phenotypic responses across environmental gradients. In this thesis, I trace the development of thought on phenotypic plasticity and present two empirical studies that implicate phenotypic plasticity in producing morphological variation in response to resource variation. The first empirical study addresses trophic plasticity, population divergence, and the effect of fine-scale environmental variation in western mosquitofish (Gambusia affinis). Offspring from two populations were fed either attached or unattached food items offered in three orientations: (1) water surface, (2) mid-water, (3) benthic, and (4) a daily rotation of the former three (fine-grained variation). Attached food induced wide heads, blunt snouts and rounded pectoral fins relative to morphology in the unattached treatment. Mid-water feeding induced elongated heads and deeper mid-bodies relative to benthic and surface feeding induced morphologies. The rotating treatment produced intermediate morphologies. Population divergence seemed related to both trophic and predation ecology. Ecomorphological consequences of induced morphologies and the need for inclusion of greater ecological complexity in studies of plasticity are discussed. The second study examines induced morphological plasticity and performance in red drum (Sciaenops ocellatus). I fed hatchery fish either hard or soft food for two months. Performance trials were designed to measure their ability to manipulate and consume hard food items. External morphology and the mass of pharyngeal crushing muscles were assessed for variation among treatments. A hard food diet induced deeper bodies and larger heads, more massive pharyngeal muscles, and initially more efficient consumption of hard food than fish receiving soft food. The observed morphological variation is in accordance with variation among species. Determining evolutionary mechanisms operating within red drum populations should eventually aid in developing and optimizing conservation efforts and ease the transition from hatchery facilities to estuaries.

Resource variation and species interactions require organisms to respond behaviorally, physiologically, and morphologically within and among generations to compensate for spatial and temporal environmental variation. One successful evolutionary strategy to mitigate environmental variation is phenotypic plasticity: the production of alternative phenotypes in response to environmental variation. Phenotypic plasticity yields multiple characters that may enable organisms to better optimize phenotypic responses across environmental gradients. In this thesis, I trace the development of thought on phenotypic plasticity and present two empirical studies that implicate phenotypic plasticity in producing morphological variation in response to resource variation. The first empirical study addresses trophic plasticity, population divergence, and the effect of fine-scale environmental variation in western mosquitofish (Gambusia affinis). Offspring from two populations were fed either attached or unattached food items offered in three orientations: (1) water surface, (2) mid-water, (3) benthic, and (4) a daily rotation of the former three (fine-grained variation). Attached food induced wide heads, blunt snouts and rounded pectoral fins relative to morphology in the unattached treatment. Mid-water feeding induced elongated heads and deeper mid-bodies relative to benthic and surface feeding induced morphologies. The rotating treatment produced intermediate morphologies. Population divergence seemed related to both trophic and predation ecology. Ecomorphological consequences of induced morphologies and the need for inclusion of greater ecological complexity in studies of plasticity are discussed. The second study examines induced morphological plasticity and performance in red drum (Sciaenops ocellatus). I fed hatchery fish either hard or soft food for two months. Performance trials were designed to measure their ability to manipulate and consume hard food items. External morphology and the mass of pharyngeal crushing muscles were assessed for variation among treatments. A hard food diet induced deeper bodies and larger heads, more massive pharyngeal muscles, and initially more efficient consumption of hard food than fish receiving soft food. The observed morphological variation is in accordance with variation among species. Determining evolutionary mechanisms operating within red drum populations should eventually aid in developing and optimizing conservation efforts and ease the transition from hatchery facilities to estuaries.

No description available.

Changes in the marine ecosystem can affect the distribution, survival, and reproductive success of seabirds. Therefore, a better understanding of factors influencing the marine distribution and abundance of seabirds can provide insight into ecological hypotheses and have important conservation implications. Yet at-sea habitat selection by seabirds has received far less attention than have investigations of their breeding biology. I studied the patterns and processes of marine habitat selection by seabirds in nearshore waters of Pacific Rim National Park Reserve, Vancouver Island, British Columbia. The study focused on comparative analyses among five sympatric species: marbled murrelet (Brachyramphus marmoratus), common murre (Uria aalge), rhinoceros auklet (Cerorhinca monocerata), pigeon guillemot (Cepphus columba) and pelagic cormorant (Phalacrocorax pelagicus). I used a multi-scaled and multi-disciplined approach combining shore-based telescope observations, vessel-based surveys, and developed new techniques for mapping nearshore seabird distributions. Patterns of habitat selection were examined through vessel-based surveys and species-habitat modeling. Vessel-based transects are fundamental to studies of seabird ecology, yet standardized protocols often fail to account for detectability biases. Distance-sampling methods were used to quantify seabird detectability along transects and showed extensive variability (20-80% of birds detected) depending on species, year, and observer. Corrected estimates of bird densities were used in habitat selection modeling, which demonstrated inter-specific and inter-annual differences in species-habitat associations. Most species showed distinct partitioning in habitats, particularly with respect to substrate and along gradients of depth and sea-surface temperature/salinity. Thus, environmental variability is a key factor structuring habitat use and coexistence in this community of piscivorous seabirds. Processes of habitat selection were studied through observations of foraging behaviour, estimates of prey availability, and spatial-statistical analysis of seabird distributions. Marbled murrelets increased foraging effort in years and seasons with scarce prey and poor oceanographic conditions and decreased foraging effort at sites with high prey availability. Despite their flexible activity budgets, increased foraging effort was inadequate to buffer reproductive success in a poor prey year, suggesting that prey availability is a limiting factor in habitat use and population growth for murrelets. Theodolite-based mapping studies examined the fine-scale distribution patterns of murrelets and murres. Nearest neighbour spatial statistics tested for competition over foraging space and showed avoidance of murres by murrelets. The results of these studies have implications for the management and conservation of the imperiled marbled murrelet in British Columbia and elsewhere in their range. I demonstrate a clear link between prey availability and consequences for reproductive success. Habitat selection models provide a step towards identifying critical marine habitats which must be protected under the Species at Risk Act. Murrelets show high forage site fidelity and associations with spatially fixed habitat components (beaches), suggesting that marine protected areas may have an important role to play in the conservation, management and recovery of murrelet populations.

The Mackenzie Delta region, NWT, has a short growing season and highly seasonal climate, and brown bears (Ursus arctos) there face many challenges obtaining their nutritional requirements. Consumption of meat by brown bears is linked to increases in population density, fecundity, growth and body size. I examined the use of Arctic ground squirrels (Urocitellus parryii), and broad whitefish (Coregonus nasus) as meat sources by Mackenzie Delta brown bears. As a preliminary step, I built an Arctic ground squirrel habitat model, using field-surveyed ground squirrel burrow locations. Using this model, I examined bears selection for Arctic ground squirrel habitat as a population, by sex and as individuals, and linked this to results of stable isotope analysis and site investigations. Bears showed little evidence of Arctic ground squirrel use at the population and sex level, but some individual bears appeared to prey heavily on ground squirrels, particularly during hyperphagia. I also described observations of a brown bear using broad whitefish in autumn, and used telemetry locations to show that other bears may also feed heavily on broad whitefish during hyperphagia. My research provides prey-specific evidence for intrapopulation niche variation among Mackenzie Delta brown bears. / Ecology

Submitted by FABIANA DA SILVA FRANÇA (fabiana21franca@gmail.com) on 2018-02-22T13:46:56Z No. of bitstreams: 1 Arquivo Total.pdf: 3728715 bytes, checksum: e1d7a2bbae94938f6e4f35edc91c9a5d (MD5) / Made available in DSpace on 2018-02-22T13:46:56Z (GMT). No. of bitstreams: 1 Arquivo Total.pdf: 3728715 bytes, checksum: e1d7a2bbae94938f6e4f35edc91c9a5d (MD5) Previous issue date: 2017-02-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The open biomes of Brazil, including Cerrado and Caatinga, are characterized by the intense seasonality and low pluviometric indices. The survival in such conditions depends upon ecological adaptations. Even so, we lack of information on the required resources for the maintenance of the species in that ambient. Psittaciformes is one of the most threatened groups among birds, either by habitat loss, or harvesting for wildlife traffic. Additionally, there is an ongoing debate on the proper destination for the animals seized from traffic, and we currently lack of data on the success of reinserting these birds back in the wild, or on the associated impacts into the wild. For the purpose of evaluating comparatively, in terms of feeding, the adaptive strategies of the Psittacidae in Brazilian open diagonal and evaluating reinserting birds seized from traffic, we colected and compiled data of six natural populations of one Cerrado’s Psittacidae (Brotogeris chiriri) and three natural populations and one group released on the Caatinga (Eupsittula cactorum). The natural populations of both species are frugivorous and seed predators. Both show variations on the diet composition with up to 50% of exclusive species between dry and rainy seasons, including exotic and cultivated on theirs diet and they do not realize migratory movements. The Caatinga species, Eupsittula cactorum, explores a higher number of species, has a higher number of plant-animal interactions and feeds on a wider strata when compared to the on of Cerrado (Brotogeris chiriri). The diet of both is characterized by a high spatial turnover, which seems to reflect the local composition of available resources. In terms of niche, both show similar behavior, narrowing the diet dimension but feeding on a wider range of strata during the dry season. Our data indicates that although presenting a narrower niche, E. cactorum explores qualitatively and quantitatively a larger pool of resources (when compared to Brotogeris chiriri), thus presenting more behavioral versatility. Regarding the released population of E. cactorum, most of the individuals survived and adapted to the environment, dispersing itself and congregating with the natural population. The released population presented lower diet richness, with the predominance of exotic and/or cultivated species, and not feeding on zoological resources. The composition differences implies on a low diet similarity with a of the natural populations and to different plant-animal interactions, as released animals shows a preference for the predation of non-reproductive parts. In terms of niche, the released population of E. cactorum presents higher homogeneity on the diet, but responds to the seasonal varieties in a similar way to the natural populations, by narrowing the niche on the diet dimension but feeding on a wide strata during dry season. Based on these results, it seems to train individuals to use plants that compose the local flora, as these could improve success under a highly seasonality such as found at the Caatinga. / Os biomas abertos brasileiros, que incluem o Cerrado e a Caatinga, são caracterizados pela marcante sazonalidade e baixos índices pluviométricos. A sobrevivência em tais condições depende de adaptações ecológicas, entretanto, são escassas informações sobre os recursos necessários para a manutenção das espécies de aves como psitacídeos, por exemplo. Os Psittaciformes são um dos grupos mais ameaçados dentre as aves, pela perda de habitat, pela predação ou competição com espécies introduzidas, caça e tráfico de animais silvestres. Além disso, falta consenso quanto à destinação dos animais apreendidos do tráfico pelos órgãos competentes, bem como, faltam dados sobre o sucesso de seu estabelecimento e/ou impactos associados, quando a opção mais viável é a soltura. Com a finalidade de avaliar comparativamente, em termos de alimentação, as estratégias adaptativas de psitacídeos na diagonal seca brasileira e se uma população originária do tráfico tende a se comportar de modo similar às populações naturais coletamos e compilamos dados de três populações naturais e uma solta de um psitacídeo da Caatinga (Eupsittula cactorum) e de seis populações naturais de uma espécie do Cerrado (Brotogeris chiriri). As populações naturais de ambas as espécies são predominantemente frugívoras e interagem predominantemente como predadores de sementes. Ambos apresentam variações na composição alimentar com até 50% de espécies exclusivas entre estações seca e chuvosa, incluem espécies exóticas e cultivadas em sua dieta e não realizam movimentos migratórios. A espécie da Caatinga, Eupsittula cactorum, explora uma riqueza maior de espécies e itens vegetais e animais, com mais interações planta-animal e estratos alimentares que a do Cerrado. A dieta de ambas é caracterizada por elevado turnover, parecendo refletir a composição da vegetação local. Em termos de nicho, ambas apresentam comportamento semelhante, com estreitamento na dimensão da dieta e ampliação na dimensão de estratos alimentares na estação seca. Nossos dados indicam que apesar de apresentar um nicho mais estreito a espécie E. cactorum explora qualitativa e quantitativamente mais recursos que Brotogeris chiriri, apresentando maior versatilidade comportamental. Quanto à população solta de E. cactorum, a maioria dos indivíduos sobrevive e se adapta, dispersando-se e apresentando diferenças na exploração de recursos em relação às populações naturais, com uma dieta menos rica, com predominância de espécies vegetais exóticas e/ou cultivadas e sem suplementação com itens de origem animal. As diferenças na composição implicam em baixíssima similaridade com a dieta das populações naturais e em diferentes interações planta-animal, com predominância de predação de partes não reprodutivas. Em termos de nicho, esta última apresenta maior homogeneidade na dieta, mas responde às variações sazonais de forma semelhante às populações naturais, com estreitamento do nicho na dimensão da dieta e ampliação na dimensão dos estratos alimentares durante a estação seca. Com base nestes resultados, sugerimos uma futura triagem rigorosa dos indivíduos a serem soltos e a aplicação de treinamento alimentar prévio utilizando plantas que compõem a flora local, pois podem aumentar o sucesso desses indivíduos em ambientes com variações sazonais drásticas como a Caatinga.

South African southern right whales (SRWs; Eubalaena australis) have been studied intensively since 1969, and annual aerial surveys between 1971 and 2006 indicate a predominant 6.9% annual population growth rate – a conservation success story after the species’ legal protection from commercial whaling in 1935. However, the prevalence of South African SRW unaccompanied adults (non-calving adults) and cow-calf pairs dropped sharply after 2009 and 2015, respectively. Additionally, the calving interval of many female South African SRWs has shifted from a three-year cycle to a four- or five-year cycle, since 2010, suggesting calving failure. This has resulted in a decrease in the population growth rate from 6.9% between 1971 and 2006, to 6.5% in 2017. SRWs are capital breeders that meet migratory and reproductive costs through seasonal energy intake, leading to strong links between their calving and foraging success. The anomalous trends in the South African SRW population have therefore raised concern about the ecological status of its broad feeding range in the Southern Ocean and ultimately about its continued population recovery. This necessitated investigation firstly into the influence of large-scale global climate drivers, Antarctic winter sea-ice extent and summer ocean productivity on the calving output of the South African SRW population. Auto-regressive integrated moving average models revealed significant model performance improvement through the inclusion of the Oceanic Niño Index (a key measure of El Niño events), the Antarctic Oscillation (the leading mode of atmospheric variability in the Southern Ocean) and chlorophyll a concentrations. The findings indicate that the South African SRW calving output appears closely influenced by not only the species’ life cycle, but also by foraging ground productivity and global climate. Secondly, the foraging strategies of South African SRWs during the 1990s (i.e. a period of high calving rates) and the late 2010s (i.e. a period of low calving rates), were assessed, through the analyses of stable carbon (δ13C) and nitrogen (δ15N) isotope values in SRW skin biopsy samples (n = 122). Results show that South African SRWs underwent a dramatic northward shift in foraging location, as well as a diversification in foraging strategy, between the 1990s and 2010s. Bayesian mixing models suggest that during the 1990s, the population foraged on prey with isotopic values similar to krill from around South Georgia. By contrast, in the 2010s, it is inferred that the population foraged on prey with isotopic values consistent with prey found in the waters of the Subtropical Convergence, Polar Front, and Marion Island. This shift could represent a new strategy to cope with changes in the availability of preferred prey or changes in habitat productivity. However, the co-occurring reproductive declines show that altering foraging strategies may not be sufficient to successfully adapt to a changing ocean. Overall, the results of this dissertation advocate that South African SRWs have recently been affected by environmental change at their foraging grounds, in turn affecting their reproductive success. Their predictive coastal presence and the existing long-term monitoring suggest that the species should be regarded as an indicator species – illustrative of climate change impacts in Southern Ocean ecosystems. / Dissertation (MSc ((Zoology))--University of Pretoria, 2020. / Zoology and Entomology / MSc (Zoology) / Restricted