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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

The Effects of Early Life History on Recruitment and Early Juvenile Survival of a Coral Reef Fish in the Florida Keys

Rankin, Tauna Leigh 12 May 2010 (has links)
Processes that influence the early life stages of fishes can significantly impact population dynamics, yet they continue to be poorly understood. This dissertation examined relationships between the environment, early life history traits (ELHTs), behavior, and post-settlement survival for a coral reef fish, Stegastes partitus, in the upper Florida Keys, to elucidate how they influence juvenile demography. Otolith analysis of settlers and recruits coupled with environmental data revealed that S. partitus surviving the early juvenile period settled at larger sizes and grew slower post-settlement. Water temperature also influenced the ranges of these and other ELHTs as well as the intensity and direction of selective mortality processes acting on some of these traits (i.e., pelagic larval duration, mean larval growth). Otolith analysis was paired with behavioral observations of newly settled juvenile S. partitus in the field to reveal that the relationship between size-at-settlement, early juvenile growth and survival is behaviorally-mediated. Individuals that were larger at settlement were more active (i.e., spent less time sheltered, swam farther from shelters) and grew more slowly post-settlement. Likewise, slower juvenile growth was associated with greater activity, more conspecific aggression, and faster escape swimming speeds. A six-year time series of recruitment densities revealed substantial temporal (interannual, seasonal, lunar) and spatial (by microhabitat, conspecific density) variability in recruitment which influenced the composition of recruits. For instance, larvae settling during the darkest phases of the moon were larger at settlement, but selective mortality processes during brighter periods removed more of the smallest settlers, resulting in juveniles with similar sizes-at-settlement regardless of when they arrived to the reef. Because recruitment strength and composition varied temporally, genetic markers (6 microsatellite and 1 mitochondrial loci) were used to determine if the genetic composition of monthly cohorts of settling larvae and juveniles also varies interannually, monthly, or across life stages. A lack of genetic structure suggested that S. partitus has a large effective population size and variation in ELHTs is not likely the result of successful spawning of a disproportionately small group of adults. As a whole, these results reveal processes associated with larval supply and post-settlement life that collectively shape juvenile demography.
2

Trait Variation in an Everglades Invasive Species: Life histories, Boldness, and Dispersal in the African Jewelfish

Lopez, Diana P 01 January 2011 (has links)
Invasive range expansion is correlated to life- history variation, boldness and dispersal behavior. The invasion of the African Jewelfish in Everglades National Park provides an opportunity to test life-history trait variation, boldness and dispersal behavior in the invasion success of this species. My study examined variation in somatic traits, boldness, and dispersal of jewelfish across their invaded range. Life histories were examined on wild individuals. Boldness and dispersal were tested in outdoor experimental tanks. Tested populations from the invasion front have higher somatic traits, but they were not bolder than longer established populations. Understanding the underlying mechanisms of invasions are key for the development of strategies looking to contain invaders and prevent their spread.
3

Como o comportamento animal pode influenciar a distribuição das espécies / The influence of animal behavior on species distributions

Lima, Herlander Correia de 21 March 2018 (has links)
Submitted by Franciele Moreira (francielemoreyra@gmail.com) on 2018-03-23T12:55:32Z No. of bitstreams: 2 Dissertação - Herlander Correia de Lima - 2018.pdf: 2848519 bytes, checksum: 21c8989e0952abc6dc4f229fa27ff46f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-03-23T14:58:47Z (GMT) No. of bitstreams: 2 Dissertação - Herlander Correia de Lima - 2018.pdf: 2848519 bytes, checksum: 21c8989e0952abc6dc4f229fa27ff46f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-03-23T14:58:47Z (GMT). No. of bitstreams: 2 Dissertação - Herlander Correia de Lima - 2018.pdf: 2848519 bytes, checksum: 21c8989e0952abc6dc4f229fa27ff46f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-21 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Research in animal personality is increasing our understanding of what prevents a species from colonizing new areas, which is one of the outstanding questions in biogeography. Some behavioral types can perform better than others in specific stages involved in range expansion. For example, a high exploratory behavior increases the chances of finding new resources in novel environments. However, inconsistent results in the literature hindered a definite recognition of the role of animal personalities on species distributions. I collected data available in the literature and performed a bayesian meta-analysis to assess which behavioral types are driving range expansion in the following biogeographical processes: dispersal, migration and invasion. I used several moderators to try to discern context-dependencies in effect sizes. A hierarchical model, with effect sizes nested within studies, revealed that more exploratory and bolder behaviors facilitate range expansion. Also, I found that invasive individuals are more likely to be more exploratory and more active than natives, while dispersers are generally bolder and more exploratory than non-dispersers. Yet, the low study sample size obtained for analysis stresses the need to conduct more primary studies. Results highlight the role of behavioral traits in species distributions and increase our knowledge about which ecological characteristics might prepare species to endure the current global environmental challenges. / A pesquisa em personalidade animal está aumentando o nosso conhecimento sobre o que previne uma espécie de colonizar novas áreas, sendo esta uma das principais questões em biogeografia. Alguns tipos de comportamento podem resultar em melhor desempenho que outros em específicos estágios de expansão do território. Por exemplo, um comportamento mais exploratório facilita a descoberta de recursos em um novo meio. Contudo, resultados inconsistentes na literatura estão dificultando um reconhecimento do papel da personalidade animal na distribuição das espécies. Coletei dados da literatura e realizei uma meta-análise bayesiana para determinar que tipos de comportamento são responsáveis pela expansão do território através dos processos biogeográficos de: dispersão, invasão e migração. Fiz ainda uso de vários moderadores na tentativa de identificar contexto-dependências nos tamanhos de efeito. Em um modelo hierárquico, usando tamanhos de efeito aninhados dentro dos estudos, mostro que um comportamento mais ousado e mais exploratório facilita o sucesso na expansão do território. Para além disso, eu demonstro que invasores são mais exploratórios e mais ativos que nativos, e dispersores são mais exploratórios e ousados que não-dispersores. Contudo, o baixo tamanho amostral obtido para as análises demonstra a necessidade de conduzir mais estudos primários. Os resultados realçam o papel dos traços comportamentais na distribuição das espécies e aumentam o nosso conhecimento sobre que características ecológicas podem preparar as espécies para resistir aos desafios das mudanças ambientais.
4

Evaluation of Physical and Behavioral Traits of Llamas (Lama glama) Associated with Aggressiveness Toward Sheep-Threatening Canids

Cavalcanti, Sandra M. C. 01 May 1997 (has links)
Canid predation poses a serious threat to the sheep industry in the United States. Llamas are becoming popular among livestock producers as part of their predation management programs but there is little information on the factors associated with llama guarding behavior. This study examined several physical and behavioral attributes of individual llamas to assess whether they might predict the aggressiveness llamas display coward canids. The study was conducted in three phases. The first involved determining some physical and behavioral traits of individual llamas. Twenty individuals were randomly assigned to one of four groups (n = 5/group) and frequencies with which animals initiated and responded to various behaviors, e.g., dominance, aggression, threats, subordination, leadership, and alertness, were documented using focal-group sampling. Individuals were then ranked according to the frequency with which they displayed each behavior. In the second phase, activity patterns of individual llamas with sheep were assessed. Lamas varied in how close to sheep they stayed (mean = 48.2 m I 3.5) as we 1 as in the way they distributed their activities. The third phase examined interactions among llamas, sheep, and a domestic sheep dog to assess their individual aggressiveness toward canids. Llamas varied in the degree of aggressiveness displayed toward the dog; some chased the dog, others ran from it, some stayed with the flock, and others did not. Llamas were ranked based on these responses. Llamas with top ranks were curious and chased the dog, but stayed close to the sheep. Bottom-ranked individuals ignored the sheep and ran from the dog. Physical and behavioral traits of llamas and their behavioral patterns with sheep were then compared with aggressiveness they displayed toward the dog. Leadership and alert behaviors were correlated with aggressiveness (r = 0.472, p = 0.064 and r = 0.607, p = 0.012, respectively) Weight of llamas was also correlated with aggressiveness (r = 0.475, p = 0.039). Llama coloration was associated with aggressiveness they displayed toward the dog (X2 = 6.003, df = 2, p = 0.049), however, color was also associated with the weight of llamas (X2 = 7.49, df = 2, p = 0.024). Traits correlated with llama aggressiveness are easily recognized and sheep producers interested in acquiring a llama should consider them when selecting livestock guardians.
5

Reproductive Behavioral and Physiological Traits in Domestic, Wild, and Hybrid Ovis

Crocker-Bedford, Kara-Lynn 01 May 1982 (has links)
This study was part of a program to develop new genotypes of sheep (Ovis spp.) and goats (Capra spp.) which are more useful for food and fiber production. The study examined the influence of domestication on behavioral and physiological traits of ewes and lambs, the influence of a single or twin offspring on ewe and lamb behaviors, and general relationships between ewes and lambs during the lambs' first month of life. Domestication has caused the intensities of observed traits to diverge greatly from the tendencies shown by wild populations. Domestication has produced increases in measurements associated with maternal care, discovery learning, tolerance or inclination for closeness with conspecifics, length of the breeding season, fertility, birth weight, and growth rate. Behaviors associated with imitative learning have decreased with domestication. Domestication has not altered the length of estrous cycle nor length of gestation. The partly domestic groups were intermediate to the most domestic and wild groups for three traits: maternal care, birth weight, and growth rate. However, other hybridization factors apparently altered the intermediate position of the partly domestic groups for the remaining traits: learning in the young, proximity of conspecifics, and fertility. The study's findings indicated that the development of new crossbreeds is an advantageous method of improving sheep and goat productivity. Some behavioral differences between ewes and their single lambs and ewes and their twin lambs resulted from the earlier physical development of singles as compared to twins: Singles played more and spent less time close to their mothers. Mothering capacities, sibling competition, and a sibling bond caused behavioral differences between ewes and their twin young and ewes and their single young: Twins suckled more, gained less weight, spent more time close to their mothers, stood more, received less sniffing from their mothers than did singles. The ewe-lamb bond did not vary between ewes and their single lambs and ewes and their twin lambs. The high occurrence of simultaneous behaviors and the maintenance of close contact between ewes and their offspring and between twins contributed to the cohesion and organization of the flock.
6

Sélection de l'habitat d'une espèce exotique en milieu urbain : le cas de la perruche à collier Psittacula krameri / Habitat selection of an exotic species in urban areas : the case of the ring-necked parakeet Psittacula krameri

Le Louarn, Marine 13 December 2017 (has links)
L’étude des mécanismes qui régissent le succès d’établissement et d’expansion des espèces exotiques apparait primordial pour l’appréhension de leurs potentiels impacts. Ce travail de thèse a pour objet d’étude la Perruche à collier \textit{Psittacula krameri}, un Psittacidé largement introduit en Europe. Les objectifs de ces travaux relèvent de l’étude des facteurs qui peuvent influencer le succès d’établissement de cette espèce en milieu urbain, par l’analyse de la sélection de l’habitat à l’étude des traits comportementaux. Les résultats montrent que la sélection de l’habitat est associée aux activités humaines, de par la préférence de l’espèce pour les zones urbanisées dans lesquelles l’espèce semble être attirée par les lumières artificielles et les espèces végétales exotiques. La comparaison de la sélection de l’habitat avec une espèce native en expansion, le Choucas des tours \textit{Corvus monedula}, a permis de montrer que la Perruche à collier est contrainte spatialement aux zones suburbaines tandis que le Choucas pourrait être capable de s’étendre aux zones les plus urbanisées. Une approche expérimentale et éthologique a mis en lumière le comportement agressif de la Perruche à collier et une monopolisation passive des ressources alimentaires, suggérant un avantage compétitif sur les espèces natives. L’ensemble des résultats de cette thèse laisse présager un potentiel de forte croissance démographique des populations et contribue aux connaissances nécessaires pour comprendre les mécanismes qui régissent l’établissement et le succès des espèces en expansion, native et exotique, tant au travers de l’étude spatiale que comportementale. / Identifying the mechanisms which may allow invasive species to establish and spread is not only a scientific question of interest but also a crucial knowledge to acquire for the management of these species. This thesis work focuses on the ring-necked parakeet, \textit{Psittacula krameri},, a Psittacine species widely introduced throughout Europe.This thesis aimed to study factors underlying the spatiotemporal distribution and which may explain the urban success of this species, from the analysis of habitat selection to behavioral traits. Results showed that habitat selection is closely related to anthropic activities, the species showing a clear preference for suburban zones and green urban areas in which the species seems to be attracted by artificial lights and exotic tree species. Using the Western jackdaw, a native range-expanding and co-occurring species, distribution modelling allowed to predict the potential future distribution and showed that, while the jackdaw may spatially expand in the more urbanized part of the city, the ring-necked parakeet may be restricted to suburban areas in the future. An ethological experiment highlighted the agonistic behavior of the ring-necked parakeet and a passive monopolization of resources, suggesting a competitive advantage over native species, exacerbated by temporal niche overlap and avoidance behavior by native species. This thesis suggests that parakeets have the potential to reach high numbers in urban areas and the overall findings provide further insight into the mechanisms allowing the establishment and spread of expanding species, native and exotic, through spatial and behavioral factors.

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