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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

American black bear distribution and density in Missouri

Wilton, Clay Michael 15 August 2014 (has links)
Understanding species’ distribution, density, and sources of bias in population estimates is critical for reliable conservation strategies. I assessed American black bear distribution, density, and abundance in southern Missouri. Using anecdotal occurrence data, I demonstrated support for a northward trend in extent of occurrences over time and a positive correlation between bear distribution and human–bear incidents. I also used GPS telemetry and camera traps to investigate detection biases in DNA hair snare methods and tested efficacy of two sampling designs for estimating density using spatial capture-recapture models. Results demonstrated that detection probability decreased following a negative asymptotic relationship with decreasing bear proximity to snares and that hair deposition rates decreased over time. Precision of estimates for low density populations with non-uniform distribution increased when using multiple arrays with intensive snare spacing. Optimizing the tradeoff among snare spacing, coverage, and sample size is important for estimating parameters with high precision.
2

Linking individual behaviour and life history: bioenergetic mechanisms, eco-evolutionary outcomes and management implications / Vinculació del comportament individual amb la història de vida: mecanismes bioenergètics, implicacions eco-evolutives i de gestió

Campos-Candela, Andrea 08 January 2019 (has links)
Animal behaviour is a state variable of the individual that deserves special attention given its determinant role in eco-evolutionary processes (Wolf et al. 2007 in Nature). The decomposition of the behavioural variation in between- and within-individual variability has revealed the existence of consistent between-individual differences referred to as personality or behavioural types (Dall et al. 2004 in Ecology Letters). Five axes of personality are usually recognized (exploration, aggressiveness, activity, sociability and boldness), and individual specificities along them tend to be correlated leading to what is known as behavioural syndromes. Recently, these patterns of covariation have been enlarged to accommodate movement behaviour within a personality-dependent spatial ecology theory (Spiegel et al. 2017 in Ecology Letters). Most animals tend to forage, reproduce and develop any activity within specific bounded space, which leads to the formation of home range (HR) areas (i.e., HR behaviour, Börger et al. 2008 in Ecology Letters). The increasing development of animal tracking technology is providing a huge amount of movement data revealing that HR behaviour is widespread among taxa and shows a large consistent variability, both at within- and between-individual level, which allows to define the existence of well-contrasted spatial behavioural types (SBTs). SBTs, as other personality traits, play an important role in selective processes as those impelled by harvesting activities. The Pace-of-Life-Syndrome (POLS) theory (Réale et al. 2010 in Philos. Trans. R. Soc. B Biol. Sci), hypothesises on how personality traits are expected to be correlated with life history (LH) traits along the fast-slow continuum (Stearns 1992 in Oxford Univ. Press) in the broadest sense. Accordingly, patterns of covariation between specific SBTs, physiology-related features and LHs would be expected to exist whenever they maximize the animal performance in a given environment. However, the way in which behavioural variation at the within-species level is translated to the wide range of LH traits remains a fundamental yet unresolved question, mainly due to the lack of a proper theoretical framework (Mathot & Frankenhuis, March 2018 in Behavioral Ecology and Sociobiology). Thus, unrevealing the mechanisms behind is certainly scientifically very exciting but also socially relevant. In such a context, this PhD thesis aimed to address from conceptual, empirical and theoretical perspectives cornerstone questions in behavioural ecology: what are the feasible mechanisms underpinning the establishment of HR areas and within-species variation, what are their consequences for animal functioning and performance (i.e., in. LH traits) at the individual and eco-evolutionary levels, or what are the implications for the assessment and conservation of wildlife of the existence of SBTs. The PhD thesis focusses in a fish heavily exploited by recreational fishers but it aims to provide general reasoning applicable to a wide range of wild animals. First, the PhD thesis proposes a mechanistic theory of personality-dependent movement behaviour based on dynamic energy budget models (i.e., a behavioural-bioenergetics theoretical model). Second, integrated in the field of animal personality (i.e., decomposition of behavioural variability into within- and between-individual’s components), it addresses empirically the study of behavioural variability in the main axis of personality for a marine fish species and looked for evidences of whether personality-mediated differences in energy acquisition may exist. Aiming to support empirically the possible connections between personality traits and space-use behaviour, the thesis provides some insights on the application of a novel-tracking algorithm to analyse the movement of individual fish submitted to different experimental conditions. Third, it provides two examples of how applying HR-related theoretical concepts may improve the management of natural resources: attending the properties of HR may facilitate the assessment of wildlife using fixed monitoring sampling stations, and considering SBTs may influence the assessment of the status of wild fish stocks. Finally, the adaptive value of the proposed behavioural-bioenergetics theory is explored by means of dynamic optimization to understand the eco-evolutionary consequences related with HR variability. In summary, this PhD thesis makes an important contribution to behavioural ecology by developing a unifying theory to test the generality and adaptive value of POLS based on dynamic energy budgets. This behavioural-bioenergetics model connects (1) personality traits (2) HR behaviour, (3) physiology and (4) LH traits through an interwoven of mass/energy fluxes, within which they interact and feedback with the ecological context. Overall, from an eco-evolutionary perspective, the proposed framework constitutes a powerful tool for exploring the ecological role of HR behaviour and predicting what combination of behavioural traits would be evolutionally favoured in a given ecological context. Moving forward to including managerial scenarios, this unifying theory provides scientifically founded knowledge that would promote to improve natural resource management by attending the behavioural component of animal populations.
3

Use of Gallery and Non-Gallery Forest by Ungulates Inhabiting the Loma Mountains Non-Hunting Forest Reserve, Sierra Leone, West Africa

Kortenhoven, Aaron Peter 01 January 2009 (has links)
This 11-month study examined rates of encountering dung pellet groups, dung piles and ungulates in gallery forests and non-gallery forests during diurnal surveys in the Loma Mountains Non-Hunting Forest Reserve (LMNHFR) in Sierra Leone, West Africa. These indices of relative abundance were then used to infer relative habitat use by the seven ungulate species on which data were collected. This study also examined the differences in rates of encountering duikers during nocturnal surveys with rates of encountering duikers during diurnal surveys to determine which time of day produces higher rates of encounter, and thereby a more accurate estimate of duiker abundance. The dung of four of the seven species, namely Cephalophus niger, Philantomba maxwelli, Tragelaphus scriptus, and Potamochoerus porcus is encountered at a higher rate in gallery forest than in non-gallery forest. Rates of encountering the dung of three species, C. silvicultor, C. dorsalis and Syncerus caffer nanus, do not differ between forest types. Rates of encountering four species, namely C. niger, P. maxwelli, T. scriptus, and C. silvicultor are higher in gallery forest than in non-gallery forest. Rates of encountering three species, namely C. dorsalis, S. caffer nanus, and P. porcus do not differ between forest types. Rates of encountering duikers ranged from three to six times higher during nocturnal surveys than during diurnal surveys for C. niger and P. maxwelli and 20 times higher for C. dorsalis. Survey timing did not affect the rate of encounter for C. silvicultor. Forest ungulates in the LMNHFR utilize gallery forests regularly. Possible reasons for the higher rates of encounter for six of the species in gallery forests compared with non-gallery forests are access to water, readily available browse resulting from annual fire damage on the periphery and interior of gallery forests, and easy access to cover for ungulates when foraging in adjacent grassland. Given the current rate of forest loss in West Africa, studies examining how forest mammals are able to persist in small forest fragments should be high priority for both government and conservation groups. The findings here give evidence that forest ungulates can and do use small areas of forest. Most importantly, the findings from this study show the global value of the LMNHFR for the conservation of large mammals endemic to the Upper Guinea Forests.

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