Date of Award:

5-2014

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Committee Chair(s)

Eugene W. Schupp

Committee

Eugene W. Schupp

Committee

Frank Howe

Committee

David Koons

Abstract

Mexican Spotted Owls are considered a threatened species by the US Fish and Wildlife Service. Therefore, they must be properly managed and protected by federal and state agencies. In this study I explored the habitat characteristics used by Mexican Spotted Owls in the canyonlands region of southern Utah. I spent three summer field seasons (May-September) from 2010 – 2013 locating Mexican Spotted Owl sites and measuring vegetative and geologic features at these sites. I found that canyon width and very tall vegetation influenced Mexican Spotted Owl presence, suggesting that these owls prefer narrow canyons that are vegetated with trees.

Based on habitat features and species life history characteristics several species distribution models (SDM) were generated for Mexican Spotted Owls in Utah. These models produce maps showing where Mexican Spotted Owls are likely to occur within Utah’s Colorado Plateau region. In order to predict Mexican Spotted Owl presence we used several vegetative and geologic variables including: elevation, aspect, surface ratio, curvature, slope, geology, and vegetation. Of these variables elevation, surface ratio, curvature, geology, and vegetation were most important in predicting where Mexican Spotted Owls occur. The variables curvature, which indicates the presence of canyons, and surface ratio, which identifies steep cliffs and walls, indicated that Mexican Spotted Owls prefer steep and narrow canyons, as opposed to flat tablelands that show little topographic variability.

These distribution maps can be used by managers to help conserve, protect, and manage Utah’s population of Mexican Spotted Owls. Managers can use the distribution maps to select new areas to survey for owls by identifying areas of potential owl occurrence. They can also identify areas of suitable habitat and designate important habitat areas, to provide protection to zones threatened with human disturbance or resource extraction. Such distribution maps can be a vital component in future conservation efforts and management of threatened and endangered species.

Chapter 1 of my thesis provides an introduction to Mexican Spotted Owls and the goals of my research project. Chapter 2 explains the construction of the SDMs and distribution maps. Chapter 3 synthesizes data on Mexican Spotted Owl habitat and how managers can effectively and efficiently employ the distribution maps presented in Chapter 2. Chapter 4 provides a conclusion to my research and future conservation implications for Mexican Spotted Owls and the respective SDMs.

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