Seagrass beds are highly valuable ecosystems with a potential nursery function for rockfishes in British Columbia. Understanding how the nursery value of seagrass habitats differs for rockfish species, and what factors create this variability in habitat value, is important for effective conservation planning. In this study, the use of Zostera marina beds in Barkley Sound by juvenile rockfishes (Sebastes spp.) was investigated. Rockfish have been observed in Z. marina beds by many researchers, however, their abundance and distribution between beds has been shown to be variable. The abundance of juvenile rockfishes in five beds was assessed in 2005 and 2006 using visual surveys. Environmental and biological variables that could potentially influence this abundance were measured concurrently. These included supply of settling fish (hereafter “settlers”), biotic and abiotic habitat characteristics. The eelgrass beds that I studied were found to differ significantly in their habitat characteristics, the abundance of settlers arriving to them, as well as the abundance of juvenile recruits in the beds. Sebastes melanops and S. caurinus were found at the sites between June and September. There was no significant relationship between the abundance of settlers arriving at a bed, and the abundance of juveniles using it. However, many of the eleven habitat characteristics investigated were significantly correlated with the abundance of either S. melanops, or S. caurinus. It is likely that these relationships arose from multiple causes which acted both pre- and post-settlement. Habitat features that were identified as correlates with high juvenile abundance value included lower epiphyte biomass, nearness to kelp habitats, lower water temperature, lower shoot density, and higher leaf width.

Seagrass beds are highly valuable ecosystems with a potential nursery function for rockfishes in British Columbia. Understanding how the nursery value of seagrass habitats differs for rockfish species, and what factors create this variability in habitat value, is important for effective conservation planning. In this study, the use of Zostera marina beds in Barkley Sound by juvenile rockfishes (Sebastes spp.) was investigated. Rockfish have been observed in Z. marina beds by many researchers, however, their abundance and distribution between beds has been shown to be variable. The abundance of juvenile rockfishes in five beds was assessed in 2005 and 2006 using visual surveys. Environmental and biological variables that could potentially influence this abundance were measured concurrently. These included supply of settling fish (hereafter “settlers”), biotic and abiotic habitat characteristics. The eelgrass beds that I studied were found to differ significantly in their habitat characteristics, the abundance of settlers arriving to them, as well as the abundance of juvenile recruits in the beds. Sebastes melanops and S. caurinus were found at the sites between June and September. There was no significant relationship between the abundance of settlers arriving at a bed, and the abundance of juveniles using it. However, many of the eleven habitat characteristics investigated were significantly correlated with the abundance of either S. melanops, or S. caurinus. It is likely that these relationships arose from multiple causes which acted both pre- and post-settlement. Habitat features that were identified as correlates with high juvenile abundance value included lower epiphyte biomass, nearness to kelp habitats, lower water temperature, lower shoot density, and higher leaf width.

Seagrass beds are highly valuable ecosystems with a potential nursery function for rockfishes in British Columbia. Understanding how the nursery value of seagrass habitats differs for rockfish species, and what factors create this variability in habitat value, is important for effective conservation planning. In this study, the use of Zostera marina beds in Barkley Sound by juvenile rockfishes (Sebastes spp.) was investigated. Rockfish have been observed in Z. marina beds by many researchers, however, their abundance and distribution between beds has been shown to be variable. The abundance of juvenile rockfishes in five beds was assessed in 2005 and 2006 using visual surveys. Environmental and biological variables that could potentially influence this abundance were measured concurrently. These included supply of settling fish (hereafter “settlers”), biotic and abiotic habitat characteristics. The eelgrass beds that I studied were found to differ significantly in their habitat characteristics, the abundance of settlers arriving to them, as well as the abundance of juvenile recruits in the beds. Sebastes melanops and S. caurinus were found at the sites between June and September. There was no significant relationship between the abundance of settlers arriving at a bed, and the abundance of juveniles using it. However, many of the eleven habitat characteristics investigated were significantly correlated with the abundance of either S. melanops, or S. caurinus. It is likely that these relationships arose from multiple causes which acted both pre- and post-settlement. Habitat features that were identified as correlates with high juvenile abundance value included lower epiphyte biomass, nearness to kelp habitats, lower water temperature, lower shoot density, and higher leaf width. / Science, Faculty of / Botany, Department of / Graduate

The distribution of the kit fox (Vulpes macrotis) in Utah was studied from 1974 to 1976 . A variety of methods were used, but a questionnaire sent annually to state and federal agencies, combined with interviews of fie ld personnel of these agencies, was found to be the most valuable. Kit foxes occur in western Utah and Washington County as previously reported. In addition, range extensions were noted in central Utah , and in Carbon, Emery, Grand, Wayne, and Garfield counties in east-central Utah. These range extensions total approximately 4,600- square miles (12,000 - square kilometers). The kit fox probably also inhabits San Juan County , but this was not confirmed. Stepwise discriminant analysis ~1as performed on groups of skull s representing the three nominal subspecies of y_. macrotis reported to occur in Utah (V. m nevadensis, arsipus , and neomex i cana). The skulls were judged to represent three distinct populations significantly different from each other in at least seven skull characteristics. Six specimens from eastern Utah and western Colorado were tentatively assigned to V m nevadensis.

I studied the habitat characteristics of Mexican Spotted Owls (Strix occidentalis lucida), a federally threatened species, in the canyonlands region of southern Utah. Vegetative and geologic features were measured within 10m wide belt plots at each current or historic nest/roost site. Based on our findings, past research, and species life history characteristics, I constructed a species distribution model (SDM) predicting Mexican Spotted Owl distribution in Utah for the Colorado Plateau region. The SDM was generated using the following inputs as important habitat variables: elevation, aspect, surface ratio, curvature, slope, geology, and vegetation. Program R was used for model development and generation. The SDM was generated using an ensemble model approach by combining three modeling techniques: random forest, logistic regression, and maximum entropy. This study combines measured habitat characteristics, with sophisticated geographic information system (GIS) tools and SDMs to provide managers with an informative and useful toolkit for Mexican Spotted Owl conservation. Chapter 2 discusses modeling techniques and SDM development. I detail how individual models were constructed using random forest, logistic regression, and maximum entropy and how these were combined into an ensemble model. Final models indicated that several vegetative and geologic characteristics were considered important habitat characteristics for predicting Mexican Spotted Owl presence within the Colorado Plateau. The SDMs produced eight distribution maps predicting Mexican Spotted Owl presence and probability of occurrence in Utah for the Colorado Plateau region. Chapter 3 explains the use of SDMs by managers and synthesizes findings of measured habitat characteristics for southern Utah. For habitat characteristics I measured a combination of vegetative and geologic features within 10m wide belts at current and historic Mexican Spotted Owl sites. Vegetative features measured included: height and species of all trees and shrubs, position of tree or shrub within plot, presence of canopy cover, and tree diameter at breast height (DBH). Geologic features measured included: geologic formation type, wall height, structure type, number of caves, and number of solution cavities. I found that canyon width and density of vegetation > 2.5 m tall were significantly correlated with Mexican Spotted Owl presence.

In the study, we determined if corridor structures use by carnivores is influenced by habitat features or prey quantity. We found that predator utilization of corridors are primarily driven by abundances of its principal prey rather than corridor characteristics but this relationship between prey abundance and carnivore distribution is species-specific. None of the measured habitat features affected the probability of carnivore detection.

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The Bachman’s sparrow (Peucaea aestivalis) is a ground-dwelling, pine-obligate species experiencing range-wide population declines due to land development and fire exclusion. We explored the effects of fire seasonality on wintering Bachman’s sparrow abundance in Southern Mississippi from 2021-2022. We used generalized linear mixed models to investigate differences in sparrow abundance and vegetation characteristics following dormant and growing season fire. We explored the effects of growing season fire on breeding territory vegetation characteristics. Our results indicate that burn type (dormant vs. growing season), native grass groundcover, and shrubs over 1m were the most significant predictors for wintering Bachman’s sparrow abundance. Additionally, native grass groundcover increased in growing season breeding territories post-fire while grass standing crop and shrubs over 1m decreased. We recommend a combination of dormant and growing season fire when feasible to promote a matrix of conditions suitable for Bachman’s sparrows throughout their life cycle in the Southeastern United States.

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