Matching Items (2)
Filtering by
- All Subjects: Plants
- Creators: Alford, Eddie J
Description
This study was designed to produce a comprehensive flora of Usery Mountain Regional Park and Pass Mountain of the Tonto National Forest. A total of 168 vascular plant species representing 46 families and 127 genera were collected or documented at this study area. Sixteen species were not native to the flora of Arizona and represent 9.5% of the flora. Nevertheless, the study area does not appear to be significantly damaged or degraded in spite of its historical and current land use. The location and types of invasive species recorded in this study will assist with implementing preventative measures to prevent further spreading of certain species. The complete list of all vascular species recorded in this study will provide a valuable tool for land management decisions and future restoration projects that may occur at this area or similar sites and invasive species control. The distribution of the saguaro (Carnegiea gigantea) population on Pass Mountain was documented through the measurement of saguaros by random sampling. ArcGIS was used to generate 50 random points for sampling the saguaro population. Analysis to determine saguaro habitat preferences based on the parameters of aspect, slope and elevation was conducted through ArcGIS. The saguaro population of Pass Mountain significantly favored the southern aspects with the highest concentration occurring in the southwest aspects at an average density of 42.66 saguaros per hectare. The large numbers of saguaros recorded in the younger size classes suggests a growing populations.
ContributorsMarshall, Laura Lee (Author) / Steele, Kelly P (Thesis advisor) / Miller, William H. (Committee member) / Alford, Eddie J (Committee member) / Arizona State University (Publisher)
Created2011
Description
Climate and land use change are projected to threaten biodiversity over the coming century. However, the combined effects of these threats on biodiversity and the capacity of current conservation networks to protect species' habitat are not well understood. The goals of this study were to evaluate the effect of climate change and urban development on vegetation distribution in a Mediterranean-type ecosystem; to identify the primary source of uncertainty in suitable habitat predictions; and to evaluate how well conservation areas protect future habitat in the Southwest ecoregion of the California Floristic Province. I used a consensus-based modeling approach combining three different species distribution models to predict current and future suitable habitat for 19 plant species representing different plant functional types (PFT) defined by fire-response (obligate seeders, resprouting shrubs), and life forms (herbs, subshurbs). I also examined the response of species grouped by range sizes (large, small). I used two climate models, two emission scenarios, two thresholds, and high-resolution (90m resolution) environmental data to create a range of potential scenarios. I evaluated the effectiveness of an existing conservation network to protect suitable habitat for rare species in light of climate and land use change. The results indicate that the area of suitable habitat for each species varied depending on the climate model, emission scenario, and threshold combination. The suitable habitat for up to four species could disappear from the ecoregion, while suitable habitat for up to 15 other species could decrease under climate change conditions. The centroid of the species' suitable environmental conditions could shift up to 440 km. Large net gains in suitable habitat were predicted for a few species. The suitable habitat area for herbs has a small response to climate change, while obligate seeders could be the most affected PFT. The results indicate that the other two PFTs gain a considerable amount of suitable habitat area. Several rare species could lose suitable habitat area inside designated conservation areas while gaining suitable habitat area outside. Climate change is predicted to be more important than urban development as a driver of habitat loss for vegetation in this region in the coming century. These results indicate that regional analyses of this type are useful and necessary to understand the dynamics of drivers of change at the regional scale and to inform decision making at this scale.
ContributorsBeltrán Villarreal, Bray de Jesús (Author) / Franklin, Janet (Thesis advisor) / Fenichel, Eli P (Committee member) / Kinzig, Ann P (Committee member) / Collins, James P. (Committee member) / Arizona State University (Publisher)
Created2012