Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (May 25, 2006) Vita. Includes bibliographical references.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on October 29, 2007) Includes bibliographical references.

Abstract Habitat selection is a crucial process affecting space use and reproductive success of birds. In this thesis, I investigated spatial and behavioural aspects of nest spacing, brood stage space use, habitat selection and factors affecting reproductive success of breeding common goldeneye (Bucephala clangula) using two large and long-term observational data sets from individually marked females. In the nesting stage, I found that spatial nesting pattern of goldeneye females changed from one year to the next and also between spatial scales. However, increasing aggregation of nesting females decreased nesting success due to increasing rate of nest desertion and nest predation especially at small spatial scale. These results provide evidence of a density-dependent population process in the common goldeneye in terms of association between annual spatial dispersion of nesting females and annual nesting success. In the brood stage, the most important factor affecting habitat selection was the amount of food. However, safe nest sites and food requirements of ducklings were not usually met in the same patch and females with broods adjusted their space-use tactics according to these critical breeding resources. Spatial divergence of these two obligatory resources induced brood movements at various distances shortly after hatching. During movements, broods used different landscape elements such as patches, corridors and matrix in a flexible way without clear fitness consequences in terms of duckling survival. Goldeneye broods suffered heavy losses especially during the early brood stage. Increasing predation risk by northern pike (Esox lucius) decreased survival of young ducklings, but frequent total brood losses suggest that also other factors affected duckling survival. Environmental factors such as temperature or rain were not related to the survival of ducklings.

Abstract For effective management of stream salmonids, it is essential to (i) assess the productive potential of a stream in relation to species-specific habitat requirements, and to (ii) identify the key factors underlying any bottleneck periods during the life cycle of a fish. For this purpose, this PhD-thesis focuses on the mechanisms of habitat selection by juvenile salmonids in boreal streams. Habitat preference curves for depth, water velocity, substrate and instream cover for brown trout (Salmo trutta L.) in river Kuusinkijoki, northeastern Finland, indicated that larger trout preferred deeper stream areas than age-0 trout did. In summer, all size-classes of trout preferred small substrates, whereas in winter, areas with cobble-boulder substrates were preferred. Winter presents a bottleneck period for trout in boreal streams; therefore winter habitat curves should be incorporated into habitat-hydraulic models when estimating habitat suitable for riverine trout in areas with severe winter conditions. The preference curves of age-0 trout were validated by correlating age-0 trout density with habitat availability at multiple sites in two boreal rivers where trout densities were monitored in 1988-1995. Substrate preference curve was effective in predicting trout densities among sites, whereas among-year variation in trout densities was best predicted by depth-related preference curves. The responses of age-0 brown trout and grayling (Thymallus thymallus (L.)) to enhancement structures were investigated in artificial stream flumes. For both species a crucial habitat factor was the availability of flow refuges, especially in winter. In another experiment, age-1 trout dominated over age-0 trout when competing for velocity and overhead cover they both found suitable, emphasizing the role of intraspecific interactions in habitat selection by trout. These results suggest that the provision of a broad diversity of microhabitats should be a major goal in rehabilitation programs for fishery purposes. A new method, combining GIS-assisted (Geographical Information System) approach with geostatistical tools, facilitated the detection of fish distribution patterns in a spatially heterogenous stream habitat. The method will likely prove valuable when determining appropriate sampling scale(s) for future studies of fish habitat selection in relation to benthic prey. Unlike Arctic bullhead (Cottus poecilopus, Heckel), trout did not show any aggregation with their benthic prey according to spatially-referenced data on the distribution of lotic fishes and benthic macroinvertebrates within a stream reach.

Parasteatoda tepidariorum is a cob-web weaving spider abundant in both urban and rural areas across the temperate regions of the globe. They are typically found in sheltered areas such as garages, porches, caves, and between stones where they are able to construct a three-dimensional web structure. Because these organisms function as both predator and prey, proper habitat selection is vital for the survival of the individual. Individuals of this species must find locations that are conducive to high levels of prey availability but also sheltered to avoid undue predator exposure. In their natural habitats, these locations tend to be shaded. Because these spiders do not readily move locations once their webs are built, proper habitat choice is important. With this information in mind, these apparent preferences in habitat may infer specific inclinations towards light exposure. These interactions, however, have not been thoroughly investigated. Because of the natural variation of light levels in these habitats, we hypothesize that these spiders may be utilizing light levels in habitat choice. In this study, we aimed to detect any indications of preferences using adult female P. tepidariorum. Spiders were captured in Sullivan and Washington counties in Tennessee and were returned to the lab where they were maintained under standard conditions prior to being placed into the experimental chamber. This experimental chamber consisted of two concentric circles that created a consistent tunnel structure for web-building throughout. A light gradient was constructed so that one side of the circular tunnel had the maximum light exposure of 410 lux and the other side faded to 0 lux. The chamber was placed in a controlled environment with a 12 h light:12 h dark cycle at ~24° C. One spider was placed into the choice chamber at a time and allowed three full days to explore and choose an environment in which to build a web. After three days, the location of the spider was recorded, and the spider was removed. The chamber was cleaned with ethanol and allowed to dry before another spider was placed into the chamber. Each spider was repeated at least twice. All individuals built webs in the dark half of the arena, and there was a significant preference for very low light (but not complete darkness). These results indicate that P. tepidariorum may select habitats based on light exposures. By investigating these preferences, we are able to get a better understanding of how P. tepidariorum interpret their environment to choose proper web locations.

No description available.

Migratory species are expected to demonstrate habitat selection that occurs at multiple spatial and temporal scales. Western monarch butterflies migrate seasonally to overwinter in groves at geographically predictable locations along the California coast. To date, overwintering habitat selection by western monarch butterflies has been studied assuming that habitat selection occurs where overwintering aggregations form, meaning at the spatial scale where monarchs form dense overwintering aggregations within overwintering groves. We argue that since western monarch butterflies are migratory, studies of habitat selection could have commingled selection at different scales into a single spatial scale. This likely leads to ignoring some levels of habitat selection, confounding the scale of habitat selection itself, and potentially misidentifying the habitat attributes under selection. Therefore, we explore monarch overwintering habitat selection to determine whether an explicit spatial framework is necessary.We studied nine groves on the coast of California and at each grove we collected temperature, humidity, and light data from grove edges, grove interiors, and aggregation locations over several weeks of the overwintering season. We tested the hypothesis that monarchs aggregate in locations within groves that have consistent attributes across groves. We find that locations on the outer edges of groves differed significantly in particular attributes of daily temperature and light from the interior of groves. Yet we find neither evidence supporting the hypothesis that the aggregation locations have a unique microclimate that differs significantly from other locations inside the grove nor that aggregation locations are uniform in their microclimatic attributes across overwintering groves. Rather, we find that the microclimatic attributes at the aggregation locations vary spatially with latitude. Thus, the overwintering climatic attributes that appear to be under selection varied spatially based on locations within groves and based on latitude of each particular grove. We conclude it will be necessary to consider spatial effects when studying western monarch butterfly overwintering habitat selection and that interpretations of habitat selection to date have commingled habitat selection at multiple spatial scales.

Photocopy of typescript. / Digitized by Kansas Correctional Industries

No description available.

Observations of animal distributions have revealed that population densities have tracked resource quality. Various models have been proposed to account for such “resource matching.” For example, the Ideal Free Distribution (Fretwell and Lucas 1970) model employs habitat selection rules which assume mobile animals evaluate available habitat patches and select the highest quality patch first. I examined movement patterns of northern crayfish (Orconectes virilis) in response to habitat patches of different quality to test this assumption. I found that animals were more likely to leave a low quality patch than a high quality patch even when there were no other patches available, suggesting that the quality of encountered resources plays a significant role in subsequent decisions about movement. However, many animals did not leave the first patch they encountered, even when better habitat existed elsewhere and was well within their ability to sample it. Finally, not all crayfish selected the best site they encountered. My studies demonstrate that the response to resources is complex, and IFDs and other distribution models may rely on overly simplified assumptions about habitat selection behavior.