A bioenergetics model was constructed for stream-resident drift-feeding salmonids. Model predictions of surplus power (energy available per unit time for lll growth and reproduction) were not statistically distinguishable from observations of surplus power in three laboratory studies. Of 40 experimental trials in these three studies, the model correctly predicted surplus power in 39 cases (p < 0.05). I collected observations of rainbow trout (Oncorhynchus mykiss) focal velocity and physical habitat availability in the Green River of northeastern Utah, USA (1988-1990). In the winter of 1988, Flaming Gorge Dam generated hydropower and delivered an lJDStable discharge regime with a higher mean discharge to the Green River. During 1989 and 1990, Flaming Gorge Dam's operation was curtailed by drought. Therefore, the Green River exhibited a more stable discharge regime with lower mean daily discharge. During winters exhibiting the stable discharge regime, all size classes of rainbow trout selected slower focal velocities than under an unstable winter discharge regime. Season had less influence on microhabitat selection of large fish than smaller individuals. Rainbow trout larger than 33 cm (total length) find and use positions with low focal velocities and high velocity shear regardless of season. In contrast, during the summer, fish less than 33 cm TL find and use positions with much higher focal velocities and greater velocity shear compared to the winter. Four bioenergetic models were tested with the focal velocity use data. Two optimal goal models produced excellent fits (r2 = 0.91 and 0.93) to observed focal velocity use of rainbow trout larger than 33 cm TL. These results were consistent with the hypothesis that large rainbow trout were finding optimal focal velocity positions in stable discharge summers and under both discharge regimes in winter. Rainbow trout movement was quantified along two scales with radio-telemetered fish: 1) weekly observations generated estimates of distances moved at intervals greater than one day and 2) multiple observations of a fish in one day produced estimates of distances moved over hours. I found an unstable discharge regime significantly reduces movement measured weekly (F = 11.10, P = 0.0019); hourly movement rates (m/h) were also reduced (F = 5.90, P = 0.0273).

No description available.

No description available.

Understanding the relationship between organisms and their environment is particularly important for the conservation and management of endangered species. The kakapo (Strigops habroptilus, Gray 1845) is a critically endangered, lek breeding, flightless nocturnal parrot endemic to New Zealand. In April 1998, a total population of fifty-six kakapo was known to survive on offshore islands. Twenty-six kakapo, thirteen males and thirteen females, were temporarily transferred to Pearl Island (518 ha), southern Stewart Island, from April 1998 to April 1999. The translocation of kakapo to Pearl Island, and subsequent breeding season, provided an ideal experimental framework to study kakapo dispersal, movement patterns, home range development, habitat selection, and lek development during the non-breeding and breeding seasons. A total of 4425 radio locations were analysed for all twenty-six birds, with a mean error polygon of 0.03 ha and an estimated average radio telemetry error of 21.6 m. Various home range analysis techniques were used to estimate kakapo home range size and overlap including: minimum convex polygons (MCP), modified minimum convex polygons (MMCP), harmonic mean analysis, adaptive kernel methods and cluster analysis. Estimates of kakapo home range size differed significantly depending on the method used (ANOVA, general linear model: F₁₃, ₁₀₇₆ = 63.99, p < 0.0001) and the season (F₂, ₁₀₇₆ = 160.75, p < 0.0001). Breeding home range size was significantly larger than non-breeding range size (mean difference = 67.6 ha, t₂₅ = 15.27, p < 0.0001). Calculations from 100% MCP and 95% harmonic mean analysis resulted in larger estimates of home range size and overlap compared to other methods. Cluster and kernel analyses appeared to give the most accurate home range representation for kakapo. Core home range areas showed a greater degree of similarity between methods. Male and female mean annual home range size did not differ significantly, whereas males had significantly (p < 0.05) larger home ranges than females during the nonbreeding season. Minimum convex polygons and harmonic mean analysis suggested that there was no significant difference in the way in which males and females interacted with each other. Kernel and cluster analyses indicated that females would overlap a greater proportion of another bird�s home range than males would. Cluster analysis also indicated that a female would have more of her home range occupied by another bird than a male would. The fact that different methods produced different quantitative results is an important consideration when using home range analysis to make conservation management decisions. Researchers must determine which method is the most appropriate for a particular research objective, species, or study area. The application of geographical information systems, ERDAS image classification techniques and global positioning systems was an integral part of this study. A large-scale vegetation classification map of Pearl Island was produced in order to quantify habitat selection by kakapo. The unsupervised classification technique produced the least accurate vegetation map, with an accuracy measure of 17-23%, compared to 52% for the supervised classification. The highest accuracy was obtained using an integrated approach involving inductive classification and deductive mapping, resulting in a vegetation classification map which correctly classified 95% of vegetation samples. Thirty-seven ecotone classes were identified and a total ecotone length of approximately 124 km was detected. Resource selection ratios and resource selection functions were estimated using a combination of discrete, continuous and area-based habitat variables. Circular buffers around used and available point locations were generated to determine whether kakapo selectively use vegetation mosaics. The probability of selection increased with increasing species diversity in each 75-metre radius buffer. Kakapo selected habitat mosaics and vegetation types with higher species diversity and moderate to high abundance of mature rimu and yellow silver pine trees.

Recently the independent multinomial selections model (IMS) with the multinomial logit link has been suggested as an analysis tool for radio-telemetry habitat selection data. This model assumes independence between animals, independence between sightings within an animal, and identical multinomial habitat selection probabilities for all animals. We propose two generalizations to the IMS model. The first generalization is to allow a Markov chain dependence between consecutive sightings of the same animal. This generalization allows for both positive correlation (individuals persisting in the same habitat class in which they were previously sighted) and negative correlation (individual vacating the habitat class in which they were previously sighted). The second generalization is to allow for heterogeneity. Here, a hierarchical Dirichlet-multinomial distribution is used to allow for variability in selection probabilities between animals. This generalization accounts for over-dispersion of selection probabilities and allows for inference to the population of animals, assuming that the animals studied constitute a random sample from that population.. Both generalizations are one parameter extensions to the multinomial logit model and allow for testing the assumptions of identical multinomial selection probabilities and independence. These tests are performed using the score, Wald, and asymptotic likelihood ratio statistics. Estimates of model parameters are obtained using maximum likelihood techniques, and habitat characteristics are tested using drop-in-deviance statistics. Using example data, we show that persistence and heterogeneity exist in habitat selection data and illustrate the difference in analysis results between the IMS model and the persistence and heterogeneity models. Through simulation, we show that analyzing persistence data assuming independence between sightings within an animal gives liberal tests of significance for habitat characteristics when the data are generated with positive correlation and conservative tests of significance when the data are generated with negative correlation. Similarly, we show that analyzing heterogeneous data, assuming identical multinomial selection probabilities, gives liberal tests of significance for habitat characteristics. / Graduation date: 2001

Understanding the ways in which animals utilize space and obtain food are central themes in modern ecology. Formulating broad principles and elucidating the factors explaining such patterns are limited, however, by the availability of data from a broad range of species and systems. This problem especially true of snakes, a predator group about which even the most basic natural history data are often entirely lacking, even among abundant, widespread, and ecologically-important species. I studied the natural history and ecosystem role of one such species, the fer-de-lance (Bothrops asper) in lowland rainforest in Costa Rica. B. asper is a large, cryptic pitviper that is highly abundant in many Central American ecosystems and is strongly relevant to human health due to high incidence of snakebite, yet its biology under natural conditions is almost entirely undocumented. I used radiotelemetry to quantify home range, movement patterns, habitat usage, and foraging behavior. B. asper was found to have smaller home ranges and reduced movement patterns than similarly-sized temperate pitvipers, likely due to a greater reliance upon ambush foraging in patches of high prey density. Snakes also demonstrated strong selection for swamp habitat, which may reflect efforts to exploit frogs as a primary food source due to low availability of small mammals at the study site. I subsequently addressed the trophic status of this B. asper population using a supplemental-feeding experiment. In comparison to control snakes, individuals receiving supplemental food had smaller home ranges, shorter and less frequent movements, increased mass acquisition, and shifted to primarily forest rather than swamp habitat. These results support the suggestion that B. asper at the study site are strongly food-limited. Finally, I tested the hypothesis that fer-de-lance mediate local seed-predation rates by influencing habitat usage and foraging behavior of rodents. A series of behavioral experiments conflicted with many existing studies in failing to support this idea, as three rodent species demonstrated little snake avoidance, and none of likely ecological relevance. Collectively, this dissertation represents the first comprehensive field study of Bothrops asper and is among the first for any tropical snake, and suggests several avenues for future research.

Habitats for juvenile chinook salmon (Oncorhynchus tshawytscha) were observed at a high flow during the spring of 1989 and at a low flow during the spring of 1991 in the lower American River of California. Parameters of microhabitats in eight macrohabitats were measured. Mean column water velocity and total water depth variables were used to statistically compare juvenile chinook salmon microhabitat distributions between and among macrohabitat type/reach and flow combinations. Using mean column water velocity and total water depth as independent variables, each macrohabitat type/reach appeared to be unique. Mean column water velocity seemed to be a better descriptor of juvenile chinook salmon habitat selection than was total water depth. Riffles appeared to be the preferred macrohabitats for large non-schooling chinook salmon at both flow levels. Root wads, woody debris, and submerged terrestrial vegetation were utilized extensively and provided a significant cover for schooling chinook salmon during the high flow period. Habitat utilization by chinook salmon appears to be influenced by nonhydraulic variables. Application of models in current instream flow studies need to include factors such as water temperature and aquatic insect production. / Graduation date: 1993

Habitat selection research has focused on the role of vegetative and geologic habitat characteristics or antagonistic behavioral interactions. Conspecifics can confer information about habitat quality and provide positive density-dependent effects that may result in improved fitness, resulting in positive behavioral responses to conspecifics as a habitat selection strategy. I conducted 3 replicated, manipulative experiments to investigate use of conspecific cues in habitat selection for the golden-cheeked warbler (Dendroica chrysoparia) using simulated conspecific vocalizations during pre-settlement and post-breeding periods, across a range of woodland canopy cover. I measured territory density, pairing, and fledging success in paired treatment and control units. Territory density was >2 times higher in treatment units across the range of canopy (P = 0.02). Pairing success was positively correlated with territory density (P = 0.008). Territory density response was higher for pre-settlement than post-breeding treatment (P = 0.004). I found pre-settlement and post-breeding conspecific cues influence golden-cheeked warbler habitat selection, inducing settlement in previously unoccupied areas, and producing aggregations within areas of similar vegetative characteristics. Better understanding of social information use in habitat selection can improve our understanding of species distributions, yielding more accurate predictive distribution models; improve our ability to predict impacts of habitat changes on habitat use, survival, reproduction, and ultimately fitness; and provide a potential tool for attracting individuals to restored or managed sites.

Goitered gazelle is one of the threatened species of Turkey living in only &amp / #289 / anliurfa region. In this study, goitered gazelles have been released to their previous habitat in Sanliurfa-Suru&ccedil / region and seven of females were collared with GPS collars. These individuals were monitored for a year and their seasonal habitat selection and home range sizes are determined by using location data recorded on the collars. In addition to 4 seasons of the year, home range and habitat selection are estimated for mating and calving periods. Also, summer period is divided to two as summer1 and summer 2 because of changing availability of water resources in study area. Seasonal home range sizes of GPS collared gazelles are estimated as average 3.61 &plusmn / 0.47 km2 for winter, 3.96 &plusmn / 0.44 km2 for spring, 4.55 &plusmn / 1.35 km2 for summer1, 2.26 &plusmn / 0.20 km2 for summer2, 3.38 &plusmn / 0.44 km2 for autumn, 1.37 &plusmn / 0.50 km2 for mating season, and 1.66 &plusmn / 0.50 km2 for calving season.Seven habitat variable layers were prepared for the evaluation of seasonal habitat selection of GPS collared female gazelles. Gazelles were selected east aspects in summer and west aspects in winter seasons and, north and flat aspects were avoided in all seasons for a year. Water can be considered the key habitat variable for the goitered gazelles. The results show that some home ranges are outside of the protected area and gazelles do not use large areas in the protected area. In order to improve conservation of gazelles, protected area should be re-arranged and shifted to more intensely used areas by gazelles.

In this thesis the demography, home range and habitat selection of a reintroduced population of Anatolian mouflon (Ovis gmelinii anatolica), which had a single remaining population, was studied to evaluate the reintroduction success and determine the conservation management interventions. For this purpose among 104 individuals reintroduced in Sariyar Wildlife Protection Area (Ankara, Turkey), 40 adults were radio-collared and 28 juvenile were ear-tagged and monitored from 2005 to 2009. The survival of the population according to the age groups (females, 0: 0.5423, 1: 0.60, 2: 0.5316, 3: 0.6637, 3+: 0.6728) and the fecundity of adult females (2: 0.2260, 3: 0.2034, 3+: 0.2034) are estimated. A population viability analysis was performed and the persistence of the population within the next 20 years was estimated. Increasing the survival rate of adult female through conservation or restocking the population with at least six adult females every year decreased the risk of extinction in the near future considerably. The year-round home ranges of the individuals ranged between 805 &ndash / 3435 ha. (Mean &plusmn / SE: 1934 &plusmn / 140 ha). The movements of the tracked individuals followed seasonal patterns: centers of activities changed according to seasons in 80% of the adult mouflon. Reintroduced mouflon selected southern aspects (p=0.001), increasing slopes &ndash / especially medium to high slope terrain &ndash / (slope &gt / 30&deg / , p=0.002), and distant locations to villages and roads. Results indicate that appropriate protective measures should be implemented immediately to mitigate the causes of juvenile mortality. Restocking the population for the next 10 years with adult females would have a stabilizing effect on the declining population and will act as a buffering mechanism during the adaptation period to the new area.