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A fragmentação florestal altera a estrutura das paisagens e as relações dos organismos com esta, sendo a movimentação um dos comportamentos mais afetado. Os indivíduos que se deparam com uma paisagem heterogênea, com áreas de habitat e de não-habitat (i.e., matriz), precisam cruzar as matrizes na procura por recursos. A opção de movimento é feita, então, através de uma avaliação dos custos e benefícios que cada área proporciona ao animal. Entre os maiores custos está o risco de predação, que pode variar conforme a estrutura de cada matriz (e.g. cobertura vegetal) e as características de cada espécie (e.g. capacidade de movimentação). Objetivando analisar o efeito de diferentes matrizes (pasto, milho e Eucaliptus) em relação ao risco de predação para a espécie Pyriglena leucoptera (Tamnophillidae) (1) verificamos se há diferenças entre as matrizes na quantidade de um dos principais predadores dessa ave, as aves de rapina, e (2) inferimos a percepção do risco de predação por meio da análise dos padrões de movimentação, realizando experimentos de translocação e monitoramento por radiotelemetria. Os resultados indicaram haver gradação de predadores nas matrizes estudadas: (milho=pasto)> Eucaliptus. O sucesso das aves em alcançar a mata foi mais alto no Eucaliptus, seguido pelo pasto e pelo milho. Os tempos médios de permanência nas matrizes também foram diferentes: (milho=Eucaliptus)>pasto. Os movimentos foram mais retilíneos no pasto e mais tortuosos no milho, enquanto o Eucaliptus mostrou uma situação intermediária. O milho provavelmente é a matriz mais arriscada para a Pyriglena leucoptera, tendo a maior densidade de aves de rapina, menor sucesso de chegada à mata e maior tortuosidade com maior tempo de permanência na matriz dos indivíduos (i.e. maior tempo de exposição ao risco). O pasto parece ser a matriz de risco intermediário, pois apresenta grande quantidade de aves de rapina, mas com animais menos tempo expostos, fazendo trajetos mais retilíneos, e o sucesso foi maior do que no milho. O Eucaliptus é a matriz de menor risco, teve a menor densidade de aves de rapina e o maior sucesso em chegar à mata. O maior tempo de permanência nessa matriz juntamente com a tortuosidade variada, e o maior sucesso de chegada à floresta, podem significar aproveitamento de recursos. Esses resultados ressaltam a importância dos estudos sobre os efeitos de diferentes matrizes no deslocamento das espécies por paisagens fragmentadas, o que afeta processos ecológicos essenciais ligados à permanência das espécies nestas condições. O manejo adequado das matrizes aparece como uma prioridade em projetos de conservação e restauração da biodiversidade nestas paisagens / Forest fragmentation alters landscape structure and its relationship with organisms, and movement is one of the most affected behaviors. Individuals who are faced with an heterogeneous landscape, composed of habitat and non-habitat areas (i.e., matrix), need to cross the non-habitat matrix in the search for resources. The choice of motion is then made by an evaluation of the costs and benefits that each area provides to the animal. Among major costs while moving through the matrix is the risk of predation, which may vary with the structure of each matrix (e.g., vegetation cover) and the behavioral characteristics of each species (e.g. movement capacity). Aiming to analyze the effect of different matrices (pasture, corn and Eucalyptus) in relation to risk of predation for the species Pyriglena leucoptera (Tamnophillidae) we (1) determined if there were differences between matrices in the density of one of the main predators of the bird, birds of prey, and (2) inferred the perceived risk of predation by performing translocation experiments with radiotelemetry monitoring to describe and analyze movement patterns in the matrix. Our results suggested a predation risk gradient in the studied matrices (corn = pasture)> Eucalyptus. The time birds spent in the matrix until reaching a forest patch was also different among matrices (corn = Eucalyptus) > pasture. Movements were straighter over the pasture matrix and more tortuous in the corn matrix, while in the Eucalyptus matrix movment showed an intermediate pattern. The success of birds to reach a forest patch was higher in the Eucalyptus matrix, followed by the pasture and corn matrix. Corn is probably the riskiest matrix for Pyriglena leucoptera, having the highest density of birds of prey, with most tortuous movement patterns and longest time spent in the matrix (i.e., longer exposure to risk) which resulted in less successful arrival to forest patches. The pasture seems to be the matrix of intermediate risk, because despite a large density of birds of prey, birds spent less time exposed to the risk, making more straight paths, which resulted in a higher success of reaching the forest than in the corn matrix. Eucalyptus was the matrix of lowest risk, had the lowest density of birds of prey and the greatest success in reaching the habitat. In this case, however, tortuosity of movement and the long time spent in this matrix did not result in decrease success of reaching a forest patch, this suggests that birds may be using resources (i.e. foraging) while moving through this less-risky matrix. This project highlights the importance of studies that quantify the effects of matrix type on the movement of organisms through fragmented landscapes, which affects essential ecological processes linked to the persistence of species in these conditions. The proper management of matrices appears as a priority for conservation and restoration of biodiversity in these human-modified landscapes

Submitted by (edna.saturno@ufrpe.br) on 2016-06-21T13:39:09Z No. of bitstreams: 1 Juliana dos Santos Severiano.pdf: 1153405 bytes, checksum: fb7c8b63673224521d85d2d6e04afa79 (MD5) / Made available in DSpace on 2016-06-21T13:39:09Z (GMT). No. of bitstreams: 1 Juliana dos Santos Severiano.pdf: 1153405 bytes, checksum: fb7c8b63673224521d85d2d6e04afa79 (MD5) Previous issue date: 2013-02-21 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The phytoplankton community can be regulated by the bottom-up controls (nutrients) and top-down (predators). The availability of nutrients has been considered as the most significant factor in this regulation, however, studies show that phytoplankton can also be strongly regulated by zooplankton. Experiments were conducted to study the effects of varying the concentration of nutrients (N: P ratio) and herbivory exercised by zooplankton on the structure and biomass of phytoplankton, with emphasis on species-specific response of phytoplankton to the effects of these factors. Sub-samples of 700 ml of water in a eutrophic environment (Apipucos reservoir, Brazil) were placed in 1 liter Erlenmeyer flasks and maintained in the laboratory for 7 days. Three experiments were conducted separately and maintained for each of these treatments included the addition of nutrients to maintain DIN different reasons: E (N: P ratio 16, 60 and 5), presence and absence of zooplankton. The nitrogen source used was a phosphorus NaNO3 and the KH2PO4. Zooplankton added was obtained in the reservoir water. Phytoplankton community in terms of total biomass was not affected when kept under different nitrogen and phosphorus reasons while herbivory caused significant reduction. The community composition has changed, with the response to the effects of these factors are species-specific. The diatom Cyclotella meneghiniana Kützing was dominant in the treatments and the main species preyed upon by zooplankton. In the absence of zooplankton, this species showed exponential growth in all the experiments, mainly in the N: P ratio 60. The ratio N: P optimal for the growth of green algae ranged from 5: 1 to 60: 1, with species with more a great reason to grow. The green algae Desmodesmus protuberans (Fritsch and Rich) E. Hegewald, D. quadricauda (Turpin) Hegewald and Pediastrum duplex Meyen did not have growth negatively affected by zooplankton, while Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju, growth was stimulated by the presence zooplankton. These results demonstrate the importance of both nutrients as of herbivory in regulating the composition and biomass of phytoplankton and reinforce the need for evaluation of phytoplankton response to specific level for a better understanding of the importance and magnitude of these factors. / A comunidade fitoplanctônica pode ser regulada pelos controles bottom-up (nutrientes) e top-down (predadores). A disponibilidade de nutrientes vem sendo considerada como o fator mais expressivo nesta regulação, entretanto, estudos mostram que o fitoplâncton também pode ser fortemente regulado pelo zooplâncton. Experimentos foram realizados para estudar os efeitos da variação na concentração dos nutrientes (razão N:P) e da herbivoria exercida pelo zooplâncton sobre a estrutura e biomassa do fitoplâncton, dando ênfase na resposta espécie-específica do fitoplâncton aos efeitos desses fatores. Sub-amostras de 700 ml da água de um ambiente eutrófico (Reservatório de Apipucos, Brasil) foram colocadas em Erlenmeyers de 1 litro e mantidas em laboratório, durante 7 dias. Três experimentos foram conduzidos separadamente, sendo mantidos para cada um destes, tratamentos que incluíam a adição de nutrientes de forma a manter diferentes razões DIN:PT (razão N:P 16, 60 e 5), com presença e ausência do zooplâncton. A fonte de nitrogênio utilizada foi o NaNO3 e a de fósforo o KH2PO4. O zooplâncton adicionado foi obtido da água do reservatório. A comunidade fitoplanctônica, em termos de biomassa total, não foi afetada quando mantida sob as diferentes razões nitrogênio e fósforo, enquanto a herbivoria provocou redução significativa. A composição da comunidade foi alterada, com a resposta aos efeitos desses fatores sendo espécie-específica. A diatomácea Cyclotella meneghiniana Kützing foi dominante nos tratamentos e a principal espécie predada pelo zooplâncton. Na ausência dos organismos zooplanctônicos, esta espécie apresentou crescimento exponencial em todos os experimentos, principalmente, na razão N:P 60. A razão N:P ótima para o crescimento das clorofíceas variou de 5:1 a 60:1, com espécies apresentando mais de uma razão ótima para crescer. As clorofíceas Desmodesmus protuberans (Fritsch e Rich) E. Hegewald, D. quadricauda (Turpin) Hegewald e Pediastrum duplex Meyen não tiveram o crescimento negativamente afetado pelo zooplâncton, enquanto Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju, teve o crescimento estimulado pela presença do zooplâncton. Estes resultados demonstram a importância tanto dos nutrientes quanto da herbivoria na regulação da composição e biomassa do fitoplâncton e reforçam a necessidade da avaliação da resposta do fitoplâncton a nível específico para uma melhor compreensão da importância e magnitude desses fatores.

Orientador: João Vasconcellos Neto / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T10:59:41Z (GMT). No. of bitstreams: 1 Andrade_RafaelBarretode_M.pdf: 418060 bytes, checksum: c8897014f5215d7a9839343a8b549c94 (MD5) Previous issue date: 2007 / Resumo: O objetivo deste estudo foi investigar padrões de forrageamento do esquilo Sciurus ingrami em frutos de palmeiras. No primeiro capítulo foi avaliada a eficiência e o aprendizado de diferentes estratégias de forrageio em frutos de Syagrus romanzoffiana. No segundo capítulo comparamos a ocorrência de diferentes estratégias de forrageio em frutos de Syagrus oleracea e S. romanzoffiana. Os resultados obtidos indicam que o esquilo S. ingrami pode utilizar diferentes estratégias de forrageio quando se alimenta de frutos de palmeiras. Algumas estratégias são evidentemente mais eficientes e possibilitam o melhor aproveitamento do endosperma gorduroso. Também foi registrado um caso de aprendizado de novas estratégias de forrageio. Essas características podem ter um papel importante na capacidade do esquilo S. ingrami de se adaptar a novos ambientes e contribuir para sua ampla ocorrência / Abstract: The objective of this study was to investigate the squirrel's Sciurus ingrami foraging patterns in palm fruits. In the first chapter, efficiency and learning of different foraging strategies in Syagrus romanzoffiana fruits was assessed. In the second chapter, we compared the occurrence of distinct foraging strategies in Syagrus oleracea and S. romanzoffiana fruits. The results indicate that S. ingrami can use different foraging strategies when feeding in palm fruits. Some strategies are clearly more efficient in obtaining the fatty endosperm within the seeds. A case of learning of new foraging strategies was also recorded. These traits probably play an important role on the squirrel's ability to adapt to new environments and contribute to its widespread occurrence / Mestrado / Ecologia / Mestre em Ecologia

Orientador: Wesley Rodrigues Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-25T04:47:26Z (GMT). No. of bitstreams: 1 Azevedo-Niero_IaraRoberta_M.pdf: 2884673 bytes, checksum: a3db764152d8b49c5c45f5689a19fb39 (MD5) Previous issue date: 2014 / Resumo: Araras-azuis (Anodorhynchus hyacinthinus) são especialistas alimentares, sendo que a população que ocorre no Pantanal se alimenta prioritariamente do endosperma de sementes de acuri (Attalea phalerata) e bocaiuva (Acrocomia sp.). Mesmo considerando o alto valor nutricional e energético das sementes, estudos apontam que araras-azuis passariam por períodos de déficit proteico durante o período de muda de penas e oviposição. É comum as araras-azuis se alimentarem destes itens no solo, onde também ocorre a predação dessas sementes por larvas de besouros bruquíneos, do gênero Pachymerus. Tais larvas são três vezes mais proteicas que o endosperma das sementes. Considerando a possibilidade de araras-azuis, ao se alimentarem no solo, se depararem com sementes já predadas por larvas de besouro, e tendo em vista algumas variações que seu alimento pode apresentar no ambiente, o intuito deste trabalho foi estudar seleção e preferências alimentares das araras-azuis em relação à oferta de alimento, além de averiguar se as larvas de besouro são utilizadas em sua dieta. As sementes de acuri e bocaiuva estão disponíveis às araras-azuis durante todo o ano. O período seco apresentou maior proporção de sementes predadas por bruquíneos do que o período úmido, para as duas espécies de palmeiras. Áreas fechadas tiveram mais sementes predadas por bruquíneos do que áreas abertas, com exceção às sementes de acuris no período seco, quando a predação foi semelhante. Independentemente da espécie da palmeira, da área, ou do período, sementes coletadas sem exocarpo estavam mais predadas por bruquíneos do que sementes com exocarpo, e sementes velhas mais predadas por bruquíneo que as novas. Sementes que continham larvas de besouro possuíam tamanhos semelhantes, porém eram mais leves que as que não continham. Araras-azuis selecionaram sementes com quatro e cinco lóculos e preferiram sementes sem exocarpo, mas não apresentaram preferências entre sementes com e sem larvas de bruquíneo. Aparentemente as araras não expeliram ou rejeitaram larvas encontradas nas sementes. Restos de larvas não foram encontrados após inspeção dos locais onde ocorreram os experimentos. Considerando que um indivíduo cativo ingeriu larvas, é possível inferir que araras de vida-livre podem ingerir larvas de bruquíneo quando as encontram. Mesmo sendo especialistas, araras-azuis exibem preferências por determinados itens alimentares. A preferência por sementes sem exocarpo corrobora estudos anteriores, que demonstraram menor tempo de manipulação, mas também maior probabilidade de predação por larvas de bruquíneo para estas sementes. Araras-azuis podem não saber discriminar entre sementes com e sem larvas de bruquíneo ou apenas podem não preferir uma em detrimento da outra. Sementes com mais lóculos talvez otimizem o aporte energético do endosperma em relação ao custo para quebrá-las, ou ainda favoreçam a chance de encontro de larvas de bruquíneo contra sementes com menos lóculos. Alimentar-se de sementes no solo pode representar um aporte adicional de proteína às araras, especialmente durante o período seco, enquanto as larvas de bruquíneos se desenvolvem em adultos. Esta estratégia representaria uma adaptação alimentar importante para a arara-azul no Pantanal, suprindo uma dieta proteica previsível no tempo e no espaço, e reduzindo os riscos de períodos de deficiência nutricional / Abstract: Hyacinth macaws (Anodorhynchus hyacinthinus) are food specialists and the population that occurs in the Pantanal feeds mainly on the endosperm of acuri (Attalea phalerata) and bocaiúva (Acrocomia sp.). Even considering the high values of energy and nutrients of those seeds, studies suggest that Hyacinth macaws undergo periods with lack of protein during moult and oviposition. Hyacinth macaws regularly feed on seeds on the ground, where Bruchinae beetle larvae of the genus Pachymerus also attack the seeds. Those larvae have three times more protein than the endosperm of the seeds. Considering that Hyacinth macaws can find seeds attacked by larvae while feeding on the ground, as well as some variations their food may present in the habitat, the aim of this work was to study the food selection and dietary preferences of the Hyacinth macaws in relation to their food supply, and to verify whether bruchid larvae are part of their diet. Acuri and bocaiuva seeds are available to macaws throughout the year. For both palm species, the dry period showed a higher proportion of seeds attacked by bruchids than the wet period. Forested areas had more seeds attacked by bruchids than open areas, except for acuris during the dry season, when predation was similar. Regardless of the kind of seed, area, or period, seeds collected without exocarp were more predated by bruchids than seeds with exocarp, and old seeds most predated than new ones. Seeds containing bruchid larvae showed similar size and lighter weight than those not containing. Hyacinth macaws selected seeds with four and five locules and preferred seeds without exocarp, but showed no preference between seeds with and without larvae. Seemingly, Hyacinth macaws not expelled or rejected larvae found in the seeds. Remains of larvae were not found after inspection of the sites where the experiments occurred. Since a captive Hyacinth macaw ingested larvae, it is possible to infer that the free-living ones can also ingest them. Even being food specialists, Hyacinth macaws exhibit preferences for certain food items. The preference for seeds without exocarp supports previous studies that demonstrate less handling time, but also higher probability of predation by bruchid larvae for those seeds. Hyacinth macaws may not be able to distinguish between seeds with and without bruchid larvae or may just not prefer one to the other. Seeds with more loci may optimize the energy intake by the endosperm regarding the costs to break it, or even favor the chance of encountering bruchid larvae against seeds with less locules. Feeding on seeds on the ground may represent an extra intake of protein to Hyacinth macaws, especially during the dry season, while bruchid larvae undergo their development into adults. This strategy would represent an important feeding adaptation to Hyacinth macaw in the Pantanal, providing a predictable protein diet in time and space, and reducing the risk of periods of nutritional deficiency / Mestrado / Ecologia / Mestra em Ecologia

Abstract Habitat selection decisions are crucial in determining fitness. Research indicates that individuals of many taxa are flexible in habitat selection and gather information prior to decision-making in order to control for environmental unpredictability. For time limited migrant birds, cues provide a quick and reliable information source with which to make habitat selection decisions. In this thesis I investigate habitat selection decisions, and their fitness consequences, of boreal passerines using heterospecifics or predators as cues. In support of the heterospecific attraction hypothesis, plots with augmented resident titmice densities attracted increased migrant densities. The predicted negative effects stemming from competition did not occur even at unnaturally high resident densities. This suggests that in the north it may always be beneficial for migrants to use residents as cues in habitat selection decisions. By manipulating habitat selection, I found that great tits (Parus major) had poorer reproductive success when forced to breed in close proximity to pied flycatcher (Ficedula hypoleuca) compared to when breeding alone. Flycatchers, in contrast, did slightly better when breeding close to tits. These results indirectly suggest that heterospecific attraction may not be a mutually positive species interaction. Indeed, flycatchers seem to parasitize the high quality microhabitat indicated by breeding great tits. I also tested if residents provide a reliable cue relative to predation risk. However, willow tit (P. montanus) nest location appeared random relative to avian predator nests. They do not appear to reliably indicate safe breeding habitats to later arriving migrants. In addition, closer proximity to breeding avian predators had a negative impact on willow tit reproductive output. Later arriving migrants may be in a better position to avoid avian predator nests during habitat selection. Pied flycatchers avoid settling in the immediate vicinity of sparrowhawk (Accipiter nisus) nests. However, nest box occupation, laying dates and initial reproductive investment (clutch size) showed a unimodal relationship with distance to sparrowhawk. A unimodal trend in these measures indicates there may be a trade-off between the costs (increased adult predation risk) and potential benefits (decreased nest predation risk) of settling in proximity to avian predator nests. Spatially predictable predation risk gradients that emanate from predator nests are termed a "predation risk landscape". Furthermore, flycatchers nesting closer to sparrowhawks produced fewer and smaller nestlings than those farther away. In addition, measures of maternal physiological stress (body condition and stress protein levels) had a negative linear relationship with distance to sparrowhawk nest. It appears that increased perceived predation risk near avian predator nests results in stressful and poor conditions for adult passerines, which results in lower reproductive output. This thesis highlights the importance of information gathering prior to making habitat selection decisions in order to optimise territory location relative to heterospecifics or predators. These decisions clearly impact individual fitness.

Master of Science / Division of Biology / Bradley J. Olson / Unicellular organisms alter their behavior and morphology in response to environmental stresses, particularly in response to immediate threats to their survival. A common tactic of predator avoidance for unicellular green algae is to aggregate to form groups. We have found that the model unicellular green algae Chlamydomonas reinhardtii forms aggregates in response to the presence of the filter feeding zooplanktonic predator, Daphnia magna. Chalmydomonas is a member of the volvocine algae, a morphologically diverse group of closely related green algae that is often used to study multicellular development. We have characterized aggregation in Chlamydomonas reinhardtii and found that it is rapid, transient and induced by signals originating from the Daphnia predators. To understand the genetic basis of cooperative aggregation we used an RNA-seq approach. RNA-seq characterized the transcriptomic response by Chlamydomonas during aggregation, and we identified 131 genes are significantly differentially expressed between predated and unpredated cultures of Chlamydomonas. Several candidate genes were characterized based on existing annotations, evolutionary history and expression profile. Evolutionary relationships between candidate aggregation genes in Chlamydomonas and their orthologs in multicellular Volvocales suggest a possible role of aggregation genes in multicellular development. Our results demonstrate that Chlamydomonas dynamically alters its morphology based on its environment and identify several candidate genes for aggregation and multicellular development.

Trophodynamics of carnivorous zooplankton in the region of the Subtropical Convergence (STC) in the Indian sector of the Southern Ocean was investigated during austral autumn (April 2007) as part of the first cruise of the Southern Ocean Ecosystem Variability Study. Within the region of the study, the STC was well defined by the 14°C surface isotherm which separated the Agulhas Return Current and Subtropical water in the north from Sub-Antarctic waters to the south. Total average abundance (3.89 ± 5.46ind 100m-3) and biomass (0.14 ± 0.27mg Dwt 100m-3) of carnivorous zooplankton south of the front were significantly higher than the total average abundance (1.33 ± 1.81ind 100m-3) and biomass (0.03 ± 0.05mg Dwt 100m-3) north of the front (p<0.001). There were no significant correlations between the selected physico-chemical (temperature and salinity) and the biological (mesozooplankton abundance and biomass) variables and the total abundance and biomass of the carnivorous zooplankton during the investigation (p>0.05 in all cases). There was no evidence of enhanced biomass and abundance values at stations occupied in the immediate vicinity of the front. Total average carnivorous zooplankton abundance was dominated by chaetognaths (Eukrohnia hamata Möbius 1875, Sagitta gazellae Ritler-Záhony 1909 and S. zetesios Fowler 1905) and euphausiids (Nematoscelis megalops Sars 1883, Euphausia longirostris Hansen 1908 and E. spinifera Sars 1883), which contributed up to 86.58 ± 32.91% of the total counts. The total average biomass was dominated by euphausiids and amphipods (Themisto gaudichaudii Guérin-Méneville 1825, Phronima sedentaria Forsskål 1775 and Vibilia armata Bovallius 1887) which contributed up to 71.45 ± 34.85% of the total counts. In general the populations of both the euphausiids and amphipods were dominated by females while the chaetognaths were dominated by juveniles. Numerical analysis identified two major zooplankton groupings within the survey area which did not coincide with the water masses within the survey area. The SIMPER procedure of the PRIMER package indicated differences between the groups were mainly attributed to changes in the abundance of the numerically dominant species rather than the presence or absence of individual species. The absence of any significant spatial patterns in the distribution of the carnivorous zooplankton suggests that the STC did not act as a biogeographical barrier during the present study. The mean feeding rates of the chaetognaths E. hamata, S. gazellae and S. zetesios were 1.82 ± 0.85prey d-1, 3.63 ± 2.08prey d-1 and 2.18 ± 0.59prey d-1, respectively. These rates correspond to a combined predation impact equivalent to <5% of the mesozooplankton standing stock or <10% of the mesozooplankton secondary production. Mesozooplankton, comprising mainly copepods was the dominant prey in the guts of the three chaetognath species. Total predation impact of the euphausiids, chaetognaths and amphipods, estimated using published daily ration data, on the mesozooplankton standing stock and secondary production ranged from 0.01% to 1.53% and from 0.03% to 30.54%, respectively. Among the carnivorous zooplankton, chaetognaths were generally identified as the dominant predators of mesozooplankton. Low predation impact of selected carnivorous zooplankton suggested that these organisms contributed little to the vertical carbon flux within the region of investigation during the study.

Please read the abstract in the section 00front of this document / Dissertation (MSc (Zoology))--University of Pretoria, 2005. / Zoology and Entomology / unrestricted

As limited prey availability and persecution by humans in response to livestock predation are key conservation concerns for the Cape leopard (Martins & Martins 2006), the present study aimed to provide more information regarding their feeding habits. The first objective was to determine whether the Cape leopard was subject to a change in their prey base and how they responded to the change. This was established by comparison of their current diet in the Cederberg and Gamka Mountains, determined by using scat analysis techniques, with a previous dietary assessment (Norton et al. 1986). The second aim was to provide a preliminary assessment of the prey preference of the Cape leopard and examine the utility of camera trap surveys to determine leopard prey preference. Leopard diet in the Cederberg and Gamka Mountains consisted largely of small- (1-10 kg) and medium-sized (10-40 kg) mammals; rock hyraxes (Procavia capensis) and klipspringers (Oreotragus oreotragus) were key prey items. In terms of regional variation in leopard diet, there was a significant difference in the average weight of prey utilized in the Cederberg and Gamka Mountains. Despite the importance of prey availability of suitable size, their flexibility in terms of prey size utilization reflected their ability to switch to smaller prey to fulfil their dietary requirements, when prey is limited. The study suggested a dietary shift, with significant variation in prey species utilization in both regions. The shift did not appear to be in response to prey scarcity, but rather a reduction in key prey species, particularly the rock hyrax. The shift involved an increase in the number of species utilized, and only a very small increase in livestock predation in both areas. There was however no significant variation in prey size category utilization. This demonstrated their dietary flexibility, as well as the importance of suitable prey sizes rather than the presence of specific prey species to fulfil their dietary requirements. The camera trap survey revealed a strong correlation between the number of camera trap days and the number of photographs taken of identifiable species. Variation of this correlation between different habitats supported the notion that individual images are a better unit to determine sampling efficiency than trap days. The camera trap survey also showed that small rodent availability was underestimated by camera trap surveillance, which resulted in poor prey preference estimation. It was therefore suggested that camera trap surveys be restricted to the surveillance of larger prey species (> 1 kg). By excluding small rodents from the analysis, prey preference could be estimated for other species and prey size categories. Small- and medium-sized mammals were significantly preferred, whereas large mammals were significantly avoided by the Cape leopard.