Thesis (M. Sc.)--Acadia University, 1997. / Includes bibliographical references. Also available on the Internet via the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves - ). Also available on the World Wide Web.

Alguns dos padrões ecológicos mais consistentemente encontrados na natureza, como as relações espécie-área e as distribuições de rank-abundância, podem ser previstas por uma classe de modelos neutros. Nesse contexto, neutralidade quer dizer que há equivalência demográfica entre os indivíduos de todas as espécies. Para os modelos dessa classe, extinções causadas por flutuações demográficas são contrabalanceadas por algum mecanismo de especiação. Cada modo de especiação deixa uma marca nos padrões ecológicos emergentes. Foi mostrado que um modelo com uma implementação mecanística de especiação gera padrões de diversidade que dependem de limites geográficos. Eu usei simulações baseadas em indivíduos com uma implementação mecanística de especiação para investigar se padrões espaciais intrínsecos das comunidades poderiam transformar os padrões de biodiversidade. Eu descobri que existe uma transição de fase no modo de especiação que depende da estrutura espacial da comunidade. Uma gama extensa de padrões encontrados na natureza puderam ser unificados em um único modelo dada essa transição de fase. Relações entre riqueza e idade de um clado podem ser melhor compreendidas considerando-se o efeito previsto de desaceleração crítica da diversificação. Uma nova interpretação foi dado ao efeito \"Clado Morto Andando\", característico dos períodos seguintes a extinções em massa. Uma redefinição objetiva e biologicamente razoável para especiação alopátrica é explorada, graças às propriedades da transição de fase descrita. Eu proponho a existência de um \"crédito de especiação\", e exploro suas possíveis implicações para a conservação a longo prazo da biodiversidade / Some of the most consistent ecological patterns encountered in nature, such as species-area relationships and rank-abundance distributions, can be predicted from a class of neutral models. In this context, neutrality means demographic equivalence between individuals of all species. Within this class of neutral models, species extinction by demographic fluctuations is counterbalanced by some speciation mechanism. Each particular speciation mode leaves an imprint in the resulting patterns. A model with a mechanistic speciation implementation was shown to generate patterns dependent on geographic constraints. I used individual based simulations with a mechanistic speciation implementation to investigate whether the intrinsic spatial patterning of organisms could transform biodiversity patterns. I found out that there is a phase transition on speciation modes that is dependent on the spatial structure of the community. An extended range of the biodiversity patterns found in nature can be unified into a single model because of this phase transition. Clade richness and age relationships may be understood by the predicted critical slowdowns in diversification. A new interpretation is given to the post mass extinction \"Dead Clade Walking\" effect. An objective and biologically reasonable redefinition of allopatric speciation is explored by exploiting the phase transition. I propose the \"speciation credit\" effect, and its potential implications for long term biodiversity conservation

<p>Blanding’s Turtles (Emydoidea blandingii) and Wood Turtles (Glyptemys insculpta) face population declines range wide, largely because of degradation and loss of habitat in the landscapes  they occupy. Studies of spatial ecology inform land managers of both the resource needs of animal  populations and provide insight on site specific conservation priorities. I examined movements  and habitat use of overlapping populations of Blanding’s Turtles and Wood Turtles at a site in  northern Michigan. I used radio telemetry to locate turtles of each species over the course of two  active seasons. I examined full active season and bi-weekly movement patterns and compared  activity between the species and sexes of each using one-way analysis of covariance (ANCOVA)  and repeated measures analysis of variance (RM ANOVA), respectively. Using multiple  commonly used spatial metrics, including range length, 100% minimum convex polygons (MCP),  95% MCP, 50% MCP, and 95% kernel density estimation (KDE), I estimated seasonal activity  ranges of turtles and examined site fidelity, making comparisons of species and sexes using two?way multivariate analysis of variance (MANOVA). Finally, I used Euclidean Distance Analysis  to examine habitat use at Johnson’s 2nd and 3rd orders of selection, making comparisons at different  levels using MANOVA. Movement analyses suggest that Blanding’s Turtles and Wood Turtles at  this site travel similar distances over the active season and during different seasonal periods,  though females of both species make slightly larger movements during the spring nesting season and male Wood Turtles move more than females in late summer. Activity ranges were individually  variable, but comparable among species and sexes. Wood Turtles do appear to exhibit site fidelity  at this site, occupying similarly sized and overlapping activity ranges year to year. Habitat  selection was evident at the 2nd order for Wood Turtles, indicating favorable use of creek, mid?canopy, and high-canopy upland habitat types and avoidance of river habitat. Blanding’s Turtles  also showed selection of habitat at the second order, with scrub-shrub and cut or burned areas  ranking highest among available habitat types. Neither Wood Turtles nor Blanding’s Turtles  showed evidence of habitat selection at the 3rd order, which may indicate an abundance of high?quality habitat available to these species at this site. Maintenance of corridors between high-use  habitat areas, and mitigation of threats especially during times of greater movement may be  advantageous to the conservation of Blanding’s Turtles and Wood Turtles at this site. </p>

An organism’s spatial ecology allows for access to essential resources such as food, mates, and escape from predators. Home range size, or the total area an organism inhabits, varies in relation to numerous factors including seasonality. During the breeding season, home range size increases in males across taxa. In addition, males usually also have larger home range sizes than females. This implicates testosterone (T) as a possible mediator of this relationship. Indeed, T causes an increase in home range size of males in numerous species of lizards. In addition to T causing an increase in home range size, it also causes an increase in coloration, which is used as a signal to deter or elicit aggressive behaviors in lizards. Potentially, contests are less common in natural settings than in the lab due to this signaling despite increased frequency overlap of home ranges in males. The larger the home range size of males, mediated through an increase in T, the more overlap with conspecifics. With this increase in spatial demand, or home range size, there is often a corresponding increase in spatially related brain regions. In reptiles, these brain regions are the medial and dorsal cortices (MC and DC respectively). The increase in cortical brain region size due to an increase in spatial demand may be mediated by an increase in neurogenesis. Proliferation of neurons occurs along the ventricles and radiate to numerous regions in the brain including the MC. With respect to the MC, immature neurons, which express the protein doublecortin (DCX), migrate from the ventricles, through the inner plexiform layer and are integrated into the cell layer. Because DCX is only expressed in recently born, migrating neurons, it can be used to measure neurogenesis. In mammals and birds, neurogenesis and growth of certain brain regions is affected by steroid hormones, including T. Here we tested two hypotheses: (1) T affects the home range size of Sceloporus occidentalis and (2) cortical brain region volumes are related to home range size and/or T which is mediated through changes in rates of neurogenesis. We surgically castrated individuals and implanted subjects with either a T-filled implant or blank implant and then released them at their initial capture sites. In addition to these castrated individuals, subjects not subjected to castration served as unmanipulated controls. Home range size of individuals in the field was quantified using a global positioning system (GPS) unit and later delineating those GPS points using minimum convex polygons (MCPs). We predicted that (1) castrated, T-treated lizards and unmanipulated control lizards would have larger home range sizes than castrated, control lizards c and (2) MC and DC cortices would be larger in volume and contain more DCX-immunoreactive cells in the lizards with the highest circulating T levels and with the largest home range sizes. We found that increased T caused an increase in the number of blue abdominal scales. We found no differences in home range size relating to T. Likewise, T did not affect MC volumes. However, we did observe a decrease in DC volume with increasing plasma levels of T. Because T did not affect home range size, it follows that we did not find an effect of T on MC volume. However, the significant result of T causing a decrease in DC volume implies a possible trade off with regards to energetics and the maintenance of brain region volumes as prior research indicates that T in increases energy expenditure and decreases foraging efforts.

Striped skunks (Mephitis mephitis) are distributed across much of North America with variable habitat preferences and behaviors recorded throughout their range. Striped skunks also readily adapt to human activity and act as hosts to many common pathogens and parasites that infect other wildlife, domestic animals, and humans. Despite how common striped skunks are in both anthropogenic and natural landscapes, few studies have investigated the influence of human activity on striped skunk ecology, and regional studies of the species in the lower Midwest are uncommon. I captured, radiocollared, and tracked striped skunks in southern Illinois during April 2018-August 2021. I used these data along with camera trap photos, necropsies, and spatial data layers in a GIS to quantify winter denning behavior, pathogen prevalence, habitat selection, and survival. Individual striped skunks used 3-21 unique dens during a single winter and denned consecutively in 1 location for 2-59 days. Three striped skunks participated in communal denning, and ≤3 striped skunks were observed at a den concurrently. Eleven mammalian species were observed at striped skunk dens, and the presence of a striped skunk at a den was positively associated with the presence of Virginia opossums (Didelphis virginiana). Human modification had no significant effect on the number of dens used by a striped skunk, but human modification, distance to stream/shoreline, and mean daily temperature had significant negative effects on striped skunk denning duration. Winter denning behavior of striped skunks in southern Illinois followed the latitudinal gradient of behavior across North America, and dens are a shared resource where direct and indirect intraspecific and interspecific interactions occur. No striped skunks tested positive for canine parvovirus (CPV) or Toxoplasma gondii, 55 striped skunks (83.33%) tested positive for Babesia microti, 24 striped skunks (28.6%) tested positive for Leptospira spp., and 5 striped skunks (6%) tested positive for canine distemper virus (CDV). As distance to permanent water increased, so did probability of infection with Leptospira spp. and CDV, which may be due to pathogen persistence in temporary water sources. No other spatial or temporal covariates affected pathogen presence indicating that pathogen transmission via striped skunks is equally likely across the urban-rural gradient. However, the high prevalence of B. microti indicates further study of vectors is needed in the area. I radiotracked 41 (20 F, 21 M) striped skunks and estimated 3,255 locations (x ̅ per individual =79 ± 43 locations; SD) for analyses of home ranges and habitat selection. Annual home ranges varied in size from 14.2-1196.0 ha (x ̅ =270.5 ±257.1 ha) and annual core areas ranged from 2.7-201.1 ha (x ̅ =55.0 ±48.5 ha). Male home ranges and core areas were larger than those of females (Home range: W =86, P <0.001, Core area: W =85, P <0.001) but did not differ by season (Home range: F3,43 =1.2, P =0.317, Core area: F3,43 =1.3, P =0.276). At the second order of habitat selection, striped skunks preferred developed, grassland/pasture, and forest cover types, areas with less canopy cover, areas with moderate levels of human modification, and spaces closer to permanent water and roads. At the third order of habitat selection, selection by individuals was significant but was so variable that trends were difficult to identify. Although striped skunk preferences are expected to differ across their geographic range, my study indicates striped skunk home ranges and habitat selection within one region can vary drastically, making it difficult to elucidate trends and further reinforcing striped skunks as a quintessential generalist species. I radiocollared 63 striped skunks and tracked them for 6,636 radiodays (x ̅ per individual =105 ± 11 days; SE) for survival analysis. Fifty-seven percent of individuals in my study had unknown fates and 43% were found deceased. I attributed 8% of mortalities to predation, 25% to vehicle collisions, 33% to disease or poor body condition, and 33% to unknown causes. Disease or poor body condition and vehicle collisions are top causes of mortality for striped skunks in other populations. I used the null model to estimate a monthly survival rate of 0.91 (95% CI: 0.87-0.94) and annual survival rate of 0.32 (95% CI: 0.20-0.48). This estimated annual survival rate is similar to reports from other stable striped skunk populations, so I expect it represents a stable striped skunk population in southern Illinois. Overall, my study highlighted variability in striped skunk preferences and behavior across an urban-rural gradient and discussed pathogen transmission implications of this variability.

<p dir="ltr">Blanding’s turtles (<i>Emydoidea blandingii</i>) and Wood Turtles (<i>Glyptemys insculpta</i>) are two threatened species that face various natural and anthropogenic threats to their populations. Many of these threats cause a decline in their recruitment, which can lead to drastic declines in populations. Females put themselves at-risk during periods of movement. My objectives were to identify portions of the season that females were most at-risk, potential nest predators, preferrable nest microhabitat characteristics, and movement of hatchlings. I studied movements in adult females of both species at a site in Northern Michigan using GPS and radiotelemetry. I compared these movements to the relative level of risk, or resistance, in the path they chose to take. I found both species had relatively similar resistance movements over the entire season. It seems that Blanding’s turtles tend to make more resistant movements during nesting, while Wood Turtles seem to be less resistant. Neither species seems to take the least resistance path available. I also conducted nesting surveys to determine nesting locations and selection characteristics at the site for both species. I did not find any characteristic that predicts nesting locations. The located nests were also recorded via trail cams to assess for predator activity. I recorded many species on trail camera review, but I did not note any predation behavior, all damage to nest cages were caused by humans and their vehicles. Lastly, I used radiotelemetry to analyze movements for hatchling turtles. Hatchlings of both species tended to make short daily movements until they reached a wetland. I also found hatchling’s succumbed to predation, desiccation, and road mortality. My data suggests further research needs to be conducted to expand our knowledge on recruitment threats. Nevertheless, I suggest active management for the threats we have noted. Nest cages seemed to be relatively successful at protecting nests, so I recommend continued nest cages to prevent or deter predators. Head-starting may be a strong strategy to help hatchlings reach a larger size before release. These larger hatchlings would also allow for larger transmitters and longer tracking times. This will help to prevent lost turtles and further our knowledge on hatchling success.</p>

Mesocarnivores, including bobcats (Lynx rufus) and coyotes (Canis latrans), fill a unique ecological role throughout much of North America, where they were once influenced by larger predators, but are now the top predators where large carnivores have been extirpated. Their adaptability, generalist traits, and ability to coexist with humans to a greater extent than many species makes them an important subject for current predator research. In addition, their recent population recovery in the case of bobcats and historical range expansion in the case of coyotes make their study timely given a potential increase in their influence on their prey and environments. I investigated how bobcats and coyotes in southern and central Illinois respond in their spatial behavior to factors in their environment like human modification and resources, including a local pulsed resource, white-tailed deer (Odocoileus virginianus) fawns. These spatial behaviors include home-ranging behaviors, habitat selection, and movement, which can be extremely informative in estimating how mesocarnivores respond to landscape heterogeneity. I found that individual variation, which is understudied in much of current spatial research, played a powerful role in all of these behaviors. Bobcats and coyotes used different strategies to respond to human modification in their home ranges, with bobcats broadly expanding their home range with increases in human modification, and clearly selecting for or avoiding these features on the landscape. Meanwhile, coyotes did not expand their home ranges with human modification, but instead displayed temporal and spatial complexity in their functional responses to human modification. These differences in response revealed a gradient in spatial behaviors animals can use to exist in anthropogenic environments, influenced by a species’ behavioral plasticity. I also found that while bobcat and coyote targeting of fawns during fawns’ most vulnerable period was weakly supported at the population-level, there was a substantial amount of individual variation in fawn exploitation. These results provided evidence that there were some specialist individuals that may contribute much more to fawn predation than others, which was somewhat influenced by habitat type. Overall, I found important interspecies and interindividual variation in mesocarnivore spatial behaviors. My study demonstrates how mesocarnivores respond to habitat and prey resources and risks associated with human development. Using this information, I present a framework for predicting how species may respond to changes in their environments, as well as provide further insight into how mesocarnivores may affect ungulate recruitment.

[Truncated abstract] The aim of this research was to define key species-environment relationships to better understand the spatial ecology of demersal fish. To help understand these relationships a combination of multivariate analyses, landscape analysis and species distribution models were employed. Of particular interest was to establish the scale at which these species respond to their environment. With recent high resolution surveying and mapping of the benthos in five of Victoria's Marine National Parks (MNPs), full coverage bathymetry, terrain data and accurate predicted benthic habitat maps were available for each of these parks. This information proved invaluable to this research, providing detailed (1:25,000) benthic environmental data, which facilitated the development and implementation of a very targeted and robust sampling strategy for the demersal fish at Cape Howe MNP. The sampling strategy was designed to provide good spatial coverage of the park and to represent the park's dominant substrate types and benthic communities, whilst also satisfying the assumptions of the statistical and spatial analyses applied. The fish assemblage data was collected using baited remote underwater stereo-video systems (stereo- BRUVS), with a total of 237 one-hour drops collected. Analysis of the video footage identified 77 species belonging to 40 families with a total of 14,449 individual fish recorded. ... This research revealed that the statistical modelling techniques employed provided an accurate means for predicting species distributions. These predicted distributions will allow for more effective management of these species by providing a robust and spatially explicit map of their current distribution enabling the identification and prediction of future changes in these species distributions. This research demonstrated the importance of the benthic environment on the spatial distribution of demersal fish. The results revealed that different species responded to different scales of investigation and that all scales must be ix considered to establish the factors fish are responding to and the strength and nature of this response. Having individual, continuous and spatially explicit environmental measures provided a significant advantage over traditional measures that group environmental and biological factors into 'habitat type'. It enabled better identification of individual factors, or correlates, driving the distribution of demersal fish. The environmental and biological measures were found to be of ecological relevance to the species and the scale of investigation and offered a more informative description of the distributions of the species examined. The use of species distribution modelling provided a robust means for the characterisation of the nature and strength of these relationships. In addition, it enabled species distributions to be predicted accurately across unsampled locations. Outcomes of the project include a greater understanding of how the benthic environment influences the distribution of demersal fish and demonstrates a suite of robust and useful marine species distribution tools that may be used by researcher and managers to understand, monitor, manage and predict marine species distributions.

In this thesis I describe fine-scale spatial patterns in rain forest termites, from the colony to the assemblage level, sampled from one hectare plots in Central African and South East Asian lowland rain forest. By so doing the ecological interactions that structure this functionally important and abundant soil community were identified. The African termite assemblage, dominated by soil-feeding termites, saturated the upper soil profile (collected from 90% of soil pits). In contrast termites were collected from &lt;50% of soil pits in Asia, with this difference reflecting the lower species densities and abundances of soil-feeding termites in Asian forests. Territoriality and inter-specific competition was shown to be important between colonies of soil-feeding species in the African plot. The termite assemblages were spatially associated with several environmental properties. However these could not explain the spatial patterns in the functional components of the assemblages. Wood-feeding termites were highly patchily distributed, due to the heterogeneous nature of their food material, but also due to possible competitive interactions for this. Humus-feeding termites were homogenously structured, due to the continuous nature of soil as their feeding and nesting material. True soil-feeding termites, unique to the African assemblage, were heterogeneously distributed despite the equally continuous nature of their feeding and nesting material. This structure may arise from facilitative interactions, such as co-operative defence against ant predation which may be intense in African systems, or through the transfer of soil material at different stages of decomposition. Competition for space is apparent in both regions, both at the colony level among soil-feeding genera, and between aggregations of functional groups. Positive and negative biotic interactions, operating at various spatial and functional scales, appear to be important in influencing how assemblage composition is spatially structured. If indeed facilitation is important in maintaining the taxonomic and functional diversity in termite assemblages, it would be valuable to confirm the mechanism(s) that drives this (i.e. predation and/or food transfer), as these may then influence ecosystem stability.