Understanding where and why organisms are distributed in the environment are central themes in ecology. Animals live in environments in which they are subject to competing demands, such as the need to forage, to find mates, to reproduce, and to avoid predation. Optimal habitats for these various activities are usually distributed heterogeneously in the landscape and may vary both spatially and temporally, causing animals to adjust their locations in space and time to balance these conflicting demands. In this dissertation, I outline three studies of Procambarus fallax in the ridge-slough landscape of Water conservation Area 3A (WCS-3A). The first section outlines an observational sampling study of crayfish population distribution in a four hectare plot, where I statistically model the density distribution at two spatial scales. ... Secondly, I use radio telemetry to study individual adult crayfish movements at two study sites and evaluate habitat selection using Resource Selection Functions. In the third section, I test the habitat selection theory, ideal free distribution, by assessing performance measures (growth and mortality) of crayfish in the two major vegetation types in a late wet season (November 2007) and early wet season (August 2009). / by Craig van der Heiden. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliographical references at the end of each chapter. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Seasonal variation in food availability is one of the primary limitations to avian populations, particularly during the breeding season. However, the behavioral responses between species may differ based on foraging strategies. I examined the influence of food availability on landscape-level habitat selection, patch-level habitat selection, and movements of two wading bird species with divergent foraging strategies, the Great Egret and White Ibis. On a landscape scale, there appeared to be a relationship among resource availability, the temporal scale of the independent variable, and whether the response was similar or different between species. At the patch level, results demonstrated a relationship between resource availability and the spatial scale of the independent variables selected by birds. Species movements were consistent with the differing strategies. This study is the first to make the link between landscape hydrology patterns, prey availability, and responses in wading bird habitat selection at multiple spatial scales. / by James M. Beerens. / Thesis (M.S.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.

Successful foraging by avian predators is influenced largely by prey availability. In a large-scale experiment at the Loxahatchee Impoundment Landscape Assessment project within the Arthur R. Marshall Loxahatchee National Wildlife Refuge, I manipulated two components of prey availability, water depth and vegetation density (submerged aquatic vegetation and emergent vegetation), and quantified the response by wading birds in terms of foraging habitat selection and foraging success. Manly's standardized selection index showed that birds preferred shallow water and intermediate vegetation densities. However, the treatments had little effect on either individual capture rate or efficiency. This was a consistent pattern seen across multiple experiments. Birds selected for certain habitat features but accrued little benefit in terms of foraging success. I hypothesize that birds selected sites with shallow water and intermediate vegetation densities because they anticipated higher prey densities, but they did not experience it here because I controlled for prey density. / by Samantha Lantz. / Thesis (M.S.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.

Um fator-chave para a conservação da biodiversidade é a adequada estruturação de áreas protegidas. Para quelônios, no entanto, a determinação do tamanho e da configuração dessas áreas requer a execução de estudos de longa duração capazes de integrar as diversas informações que garantam o sucesso reprodutivo, o recrutamento de novos indivíduos e o entendimento de todos os aspectos necessários para o extenso ciclo de vida, assegurando, portanto, diversidade genética que proporcione a persistência das populações desses animais ao longo do tempo. Um total de dezenove cágados adultos (10 machos e nove fêmeas) foram equipados com rádio-transmissores e outros 18 animais (11 fêmeas e sete machos) foram monitorados com bobinas de rastreamento com a finalidade de determinar a área de vida, os padrões de movimentação e o uso e seleção de habitat de Hydromedusa maximiliani, uma espécie de cágado Vulnerável e endêmica de áreas de Mata Atlântica, um dos ecossistemas mais ameaçados do planeta. Por meio de diferentes estimadores (Polígono Convexo Mínimo ou MCP \"Minimum Convex Polygon\", Kernel e Cluster para os dados de telemetria) foi possível observar que H. maximiliani apresenta área de vida que varia entre 0,2 e 1,5 ha ao longo de um período anual, com média de 0,4 ha, independentemente da estação do ano. Apesar da diferença de tempo empregado no monitoramento pelos dois métodos (72 horas para o bobinas de rastreamento e 15 meses para a telemetria), observou-se que o tamanho da área de vida não foi diferente quando comparadas as estimativas obtidas. Esse resultado, bem como o baixo deslocamento apresentado pela espécie (3 a 138 m/dia) e o intenso uso de refúgios pelos indivíduos monitorados, pode ser explicado pelo comportamento sedentário e intensa fidelidade ao ambiente aquático. Contudo, esse aspecto não descarta a sua relação com o ambiente terrestre, o que, entretando, necessita de melhor e mais prolongada investigação, uma vez que a seleção de locais para a postura dos ovos é um comportamento maternal sujeito à seleção natural e que contribui para a sobrevivência e a variação fenotípica da prole. / A key factor in conservation biology is a suitable design of protected areas. Long-term study is required when determining the size, structure, shape of these areas for freshwater turtles, thereby integrating essential information to guarantee the reproductive success, recruitment of new individuals into the population and persistence of the population over the years. Nineteen adult animals (10 males and 9 females) were fitted with radio-transmitters in order to analyze the home range, movement patterns, habitat use and selection of the vulnerable freshwater Hydromedusa maximiliani, an endemic and vulnerable freshwater turtle from Atlantic Rainforest in Brazil, one of the world\'s most threatened ecosystems. Another eighteen adult animals (11 females and 7 males) were also monitored with the technique of thread-bobbins. Three different methods such as MCP \"Minimum Convex Polygon\", Kernel and Cluster were applied to measure home range size which varied between 0.2 to 1.5 ha throughout a year period of monitoring, with mean size of 0.4 ha either for the wet or the dry season. No difference was found when the home range measured using different methods were compared even with the time difference between them (72 hours for thread-bobbins and 1 year for telemetry). This result associated with the low movements showed by Hydromedusa maximiliani (3 to 138 m/day) and the intense use of burrows can be explained by the sedentary behavior and intense site fidelity of the turtles with the river. Nevertheless, the importance of the terrestrial habitat for freshwater turtles is already known though longterm monitoring is necessary to study this aspect which would contribute to future conservation strategies including nests sites and also habitat use and selection of young turtles.

Os estudos sobre a relação habitat-espécie são importantes para a conservação, pois geram conhecimento sobre características de habitat essenciais para uma população. A incorporação destas informações em planos de conservação permite um manejo mais inteligente tanto da fauna como das áreas a serem preservadas. O presente estudo teve como objetivo estudar o uso e a seleção de habitat de Saltator atricollis e Cypsnagra hirundinacea na Estação Ecológica de Itirapina, região central do estado de São Paulo, Brasil. Ambas espécies são aves endêmicas do Cerrado e ameaçadas de extinção no Estado de São Paulo. O estudo foi desenvolvido entre setembro e dezembro de 2007 e setembro de 2008. O habitat foi analisado em duas escalas: o macro-habitat e o micro-habitat. Para analisar o habitat foram dispostos sistematicamente 84 pontos de amostragem na área de estudo. Na análise do macro-habitat foram utilizadas informações sobre o uso-disponibilidade das diferentes fisionomias sendo comparadas por meio do intervalo de confiança de Bailey. No estudo de micro-habitat foram medidas 11 características estruturais da vegetação ao redor de cada ponto de contato com S. atricollis, com C. hirundinacea e nos 84 pontos de amostragem. Para analisar as associações entre as características estruturais e as aves foi utilizado modelos de regressão logística selecionados pelo Critério de Informações de Akaike (AIC). Saltator atricollis selecionou áreas de campo cerrado, utilizou na mesma proporção que o esperado as áreas campestres e utilizou menos que o esperado o cerrado sensu stricto. Cypsnagra hirundinacea utilizou na mesma proporção que o esperado as áreas campestres e o campo cerrado enquanto o cerrado sensu stricto foi utilizado menos que o esperado. Quanto ao micro-habitat os melhores modelos para explicar a presença de S. atricollis incluíram maior densidade de árvores maiores que 2 m de altura e menor densidade de Syagrus petrea e de arbustos com até 1 m de altura. A presença de árvores é importante para a espécie, pois são utilizadas como poleiros durante o comportamento de sentinela. As altas densidades de Syagrus petrea e arbustos baixos (< 1m) podem diminuir a quantidade de moitas de gramíneas (utilizadas para a construção de ninhos) já que ambos ocupam o mesmo estrato. Assim, indiretamente, a presença de Syagrus petrea e arbustos baixos (< 1m) podem diminuir a disponibilidade de sítios reprodutivos. Além disso, podem atrapalhar o forrageamento por dificultar a utilização do estrato herbáceo. Os modelos que explicaram melhor a presença de C. hirundinacea foram representados por uma maior densidade de arbustos e árvores intermediárias e altas (entre 1 e 2 m, entre 2 e 4 m e maiores que 4 m de altura), maior densidade de braquiária e menor densidade de Attalea geraensis e de solo exposto. A presença de árvores é importante, pois a espécie as usa para forragear, construir ninhos e vigiar contra predadores. A relação positiva com a braquiária pode estar relacionada ao fato da espécie não utilizar o estrato herbáceo e ao mesmo tempo a invasão dessa gramínea, possivelmente, ainda não deve ter alterado a estrutura da vegetação lenhosa. Já a relação inversa entre a presença de C. hirundinacea e a densidade de solo exposto e de A. geraensis deve ocorrer, pois em ambientes com alta densidade dessas variáveis provavelmente há um baixo número de árvores o que diminui a disponibilidade de sítios de forrageamento e reprodutivos. Portanto para a manutenção dessas espécies é importante preservar as fisionomias abertas do Cerrado, as quais estão desaparecendo no estado de São Paulo, além disso recomenda-se manter nessas fisionomias a presença de algumas árvores e evitar a dominância de palmeiras rasteiras. / Studies about habitat-species relationships are important for conservation, because they generate knowledge about the essential characteristics of a habitat for a population. Incorporation of such information in conservation plans allows for a more intelligent management of both fauna and habitats that should be preserved. The aim of this study was to investigate the habitat use and selection by Saltator atricollis and Cypsnagra hirundinacea at Estação Ecológica de Itirapina in central State of São Paulo, Brazil. Both species are endemic birds of the Cerrado (Brazilian Savannah) and they are considered threatened with extinction in the State of São Paulo. The study was developed from September to December of 2007 and in September 2008. Habitat was analyzed in two scales: macrohabitat and microhabitat. To analyze the habitat 84 sampling points had been distributed at the study area. Macrohabitat selection was analyzed based on use-availability data of physiognomy and performing Baileys confidence interval. To investigate the use of the microhabitat there were estimated eleven structural characteristics of vegetation. These characteristics were described in each exact point that S. atricollis and C. hirundinacea had seen and in the 84 sampling points. The associations between the structural characteristics and the birds were identified by logistic regression models selected by Akaike Information Criteria (AIC). Saltator atricollis selected campo cerrado physiognomies (grassland savannah), it use campos (grasslands) at the expected proportion and cerrado sensu stricto (woodland savannah) less than expected proportion. Cypsnagra hirundinacea used both campos and campo cerrado areas at expected proportions while cerrado sensu stricto was used less than expected proportion. At the microhabitats level, the best models to explain the presence of S. atricollis included greater density of trees higher than 2 meters, lesser density of Syagrus petrea, and lesser density of bushes of to up to 1 meter height. The presence of trees is important to this specie, because the trees are used as perches during sentinel behavior. The high density of Syagrus petrea should diminish the amount of grassy because they use the same space on the habitat. Birds use the grassy to make its nest and the presence of Syagrus petrea and short bushes (< 1m) should indirectly reduce places for reproductive sites and might make foraging more difficult. The best models to explain the presence of C. hirundinacea were the one represented by a greater density of bushes and, trees of intermediate to greater height (between 1 and 2 meters, between 2 and 4 meters, and higher than 4 meters), greater density of Brachiaria grasses and lesser density of Attalea geraensis and exposed ground. The presence of trees is important because the species use them to forage, build nests and watch against predators. The positive relation with Brachiaria grasses might be occurs because C. hirundinacea dont use the herb layer. Possibly, the invasion of the Brachiaria grasses not having changed the structure of the vegetation yet. The inverse relation between the bird specie and the presence of exposed ground and A. geraensis, should occur because in habitats with high density of exposed ground and A. geraensis there are few places to feed and to reproduction. Therefore, to the maintenance of these birds species it is important preserving the open physiognomies of the Cerrado, which are disappearing from the State of São Paulo. Its also necessary to keep in theses physiognomies the presence of a few bushes and trees and also avoid the dominance of A. geraensis and Syagrus petrea.

No description available.

Kakapo (Strigops habroptilus) are a flightless, nocturnal parrot endemic to New Zealand. Thought to be extinct within their natural range, kakapo are currently listed as nationally critical. The current population of 86 individuals is managed by the Department of Conservation’s National Kakapo Team on two offshore islands in southern New Zealand, with all females of breeding age on Codfish Island (Whenua Hou). Kakapo only breed once every two to five years, coinciding with the mast fruiting of specific plant species. On Codfish Island, the proportion of adult female kakapo that breed in rimu (Dacrydium cupressinum) fruiting years is dependent on the quantity of fruit produced, with fewer females attempting to breed during low mast years. The purpose of this research is to investigate why only some adult female kakapo breed in low rimu fruiting years on Codfish Island, specifically assessing if foraging home range size and/or habitat selection influence breeding. A total of 506 location points were collected at night for 18 adult female kakapo between March and May 2006. These were used to estimate foraging home ranges and to assess if kakapo select for particular types of vegetation. Ecological Niche Factor Analysis was used to determine the relative importance of habitat variables in the distribution of female kakapo and to predict areas of suitable breeding habitat when rimu fruit is limited. The breeding success of individuals in 2005, a low rimu mast year, was used to identify if differences in home ranges or habitat selection occurred between breeding and non-breeding females. The large variation in foraging home range sizes recorded in this research was consistent with previous studies. Foraging home range sizes were on average twice the size for breeders than for non-breeders, suggesting that adult female kakapo may be limited in their ability to breed by the size of the area they occupy. Adult female kakapo did not randomly use vegetation on Codfish Island as some vegetation types were not used, while others were common inside foraging home ranges. Adult female kakapo utilise a broad niche and are capable of surviving in a wide range of habitats. However, breeding females were more specialised in their niche requirements than non-breeders, with breeders utilising areas with higher abundances of mature rimu trees. Females occurred in high elevation, flat areas of the island but this may have been because this is where appropriate vegetation types occurred. During low rimu mast years, breeding adult females were predicted to occupy habitat in high elevation, plateau areas with a high abundance of rimu. Areas identified as sub-optimal habitat for breeding included the coastal areas, the lower elevation area of the main valley and some ridgelines. The home ranges of all 10 breeding females contained some optimal habitat, while females who did not breed were more likely to be located in sub-optimal habitat. Although there were significant areas of optimal breeding habitat not occupied by adult female kakapo, other kakapo may have been present in these areas. To increase the proportion of females that breed in low rimu mast years, it may be necessary to remove sub-adult females or surplus adult males living in optimal breeding habitat from the island. Alternatively, females in sub-optimal breeding habitat could be fed supplementary foods or transferred to other islands where there is unoccupied suitable breeding habitat available.

Shallow sheltered Baltic Sea bays are ecologically important habitats that harbour a unique vegetation community and constitute vital reproduction areas for many coastal fish species. Knowledge about the invertebrate community in these bays is, however, limited. This thesis examines the macroinvertebrate community in shallow sheltered Baltic Sea bays and how it is affected by: (1) the natural morphometric isolation of bays from the sea due to post-glacial land uplift; and (2) differences in vegetation types. The invertebrate biomass and number of taxa was found to decrease with increased bay isolation. The taxon composition changed from dominance by bivalves and gastropods in open bays to a community composed of a larger proportion of insects in isolated bays. Stable isotope analysis indicated epiphytes and periphyton as the major energy resources for most of the examined consumers, but the relative importance of these in relation to larger plants decreased for some consumers with increased bay isolation. A comparison of invertebrate abundance between plants revealed a close relationship with morphological complexity of the plants. More complexly structured plants had higher invertebrate abundance than plants with simpler morphology. The results suggest that management of these coastal habitats should be dynamic and take into consideration the natural change in invertebrate community resulting from the slow bay isolation process. In addition, the results imply that changes in the aquatic vegetation due to anthropogenic influences could induce changes in the invertebrate community as the plant habitat structure is altered. A changed invertebrate community may in turn affect higher trophic levels since invertebrates are important food for many fish and waterfowl species. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 4: In press.

<p>The principle objective of this investigation was to develop an understanding of the physiological response and ecological aspects of winter torpor of small carnivores, specifically striped skunks (<i>Mephitis mephitis</i>) in the northern environment. An experiment was undertaken to investigate the physiological response of skunks to solitary and communal over-winter strategies. Solitary skunks were able to undergo daily torpor to conserve energy to survive the winter, whereas communal skunks were able to use social huddling to reduce energy expenditure and rarely entered torpor. Due to seasonal changes in life requirements, den selection criteria change throughout the year. I examined the landscape metrics and habitat characteristics surrounding dens to evaluate the hierarchical selection and use of dens during winter (i.e., for torpor) and summer (i.e., for parturition). Den structures commonly used for winter dens were buildings, whereas den structures used for maternity dens were rockpiles and underground burrows. Habitat surrounding den sites influenced den use; animals chose den sites closer to roads, water sources, habitat edges, and crop fields. Seasonal movements of skunks from winter dens to the following summer home ranges were examined with respect to winter grouping (i.e., solitary or communal) and winter den structure (i.e., underground burrow or building) to investigate factors that influence spatial distribution of skunks. Male and female skunks moved similar distances (~1.5 km) from winter dens to the center of home ranges established in summer, irrespective of winter grouping status and winter den structure use. Due to limited movement in spring, skunks from communal winter dens had higher spatial overlap of summer home ranges than did skunks from solitary dens, producing spatial aggregation of skunk activities surrounding winter communal den sites. Consequently, winter communal dens represent localized hotspots in the landscape. The effects of extrinsic variables (i.e., environment and diseases) and intrinsic characteristics (i.e., age, gender, and body condition) on cumulative winter survival rate were examined. Winter survival rates were driven mostly by winter condition (i.e., low ambient temperature and snow depth), rabies, and body condition. These results suggest that winter severity probably poses a limit on the northern distribution of the species.</p>

<p>The principle objective of this investigation was to develop an understanding of the physiological response and ecological aspects of winter torpor of small carnivores, specifically striped skunks (<i>Mephitis mephitis</i>) in the northern environment. An experiment was undertaken to investigate the physiological response of skunks to solitary and communal over-winter strategies. Solitary skunks were able to undergo daily torpor to conserve energy to survive the winter, whereas communal skunks were able to use social huddling to reduce energy expenditure and rarely entered torpor. Due to seasonal changes in life requirements, den selection criteria change throughout the year. I examined the landscape metrics and habitat characteristics surrounding dens to evaluate the hierarchical selection and use of dens during winter (i.e., for torpor) and summer (i.e., for parturition). Den structures commonly used for winter dens were buildings, whereas den structures used for maternity dens were rockpiles and underground burrows. Habitat surrounding den sites influenced den use; animals chose den sites closer to roads, water sources, habitat edges, and crop fields. Seasonal movements of skunks from winter dens to the following summer home ranges were examined with respect to winter grouping (i.e., solitary or communal) and winter den structure (i.e., underground burrow or building) to investigate factors that influence spatial distribution of skunks. Male and female skunks moved similar distances (~1.5 km) from winter dens to the center of home ranges established in summer, irrespective of winter grouping status and winter den structure use. Due to limited movement in spring, skunks from communal winter dens had higher spatial overlap of summer home ranges than did skunks from solitary dens, producing spatial aggregation of skunk activities surrounding winter communal den sites. Consequently, winter communal dens represent localized hotspots in the landscape. The effects of extrinsic variables (i.e., environment and diseases) and intrinsic characteristics (i.e., age, gender, and body condition) on cumulative winter survival rate were examined. Winter survival rates were driven mostly by winter condition (i.e., low ambient temperature and snow depth), rabies, and body condition. These results suggest that winter severity probably poses a limit on the northern distribution of the species.</p>