Discipline: Ecology Environmental and Earth Sciences
Subcategory: Climate Change
Room: Exhibit Hall
Kyra Harvey - Virginia State University
Co-Author(s): Brooke Rose, University of California Riverside, Riverside, CA; Loralee Larios, University of California Riverside, Riverside, CA
Climate change is a prominent global issue and as climate change persists, it is imperative that we understand how this will affect plant species in their environments. In California, climate change is predicted to cause an increase in drought. However, the Riversidean Alluvial Fan Sage Scrub (RAFSS) community in southwest California has already adapted to dry environmental conditions. Drought adapted plants may be less vulnerable to future environmental changes that increase dry areas. In this study, I explored the effects of climate change on three California plant species of different conservation statuses within the RAFSS community. The three focal species are the abundant Turkey Mullein (Croton setigerus), the sensitive Parry’s Spineflower (Chorizanthe parryi), and the endangered Slender-horned Spineflower (Dodecahema leptoceras). In light of the drought tolerance of the community, I hypothesized that all species would have an increase in available habitat suitability, with the abundant species retaining the highest proportion of suitable habitat under climate change.To identify suitable habitat in geographic space under current climatic conditions (years 1980-2010), I produced Maxent species distribution models (SDMs) for each species using current occurrences, climatic, (minimum temperature, evapotranspiration, summer precipitation, winter precipitation) and soil data (pH, depth, clay%, sand%). Each model’s area under the receiver operating characteristic (ROC) curve (AUC) was evaluated for the ability to discriminate between species’ occurrence points and background points. Each model had a score above 0.89. These models were then used to predict suitable habitat areas with future climate change under a warm, dry scenario (years 2040-2069). As expected, all species experienced an overall increase in suitable habitat area, with Croton setigerus increasing by 43.7%, Chorizanthe parryi increasing by 2%, and Dodecahema leptoceras increasing by 24.7%. However, we found that considering only the southwestern region of California, where RAFSS is found, our model predicts an 8% decrease in habitat suitability for Croton setigerus. Our data also showed location shifts between the current and future suitability areas, suggesting the currently suitable areas are not the same suitable areas in the future. This approach shows that an abundant species can be vulnerable to habitat shift and that future conservation efforts can focus on dispersal dynamics to ensure species have the mobility to move into more suitable habitats.
Funder Acknowledgement(s): Funding was provided by a grant to Paul Nabity from University of California Office of the President. Funding was also provided by the Vulcan Foundation to Loralee Larios.
Faculty Advisor: Sarah Melissa Witiak, firstname.lastname@example.org
Role: For this research, I observed the species in the field, entered occurrence and climate data into the model in R, cleaned the data, produced SDM models for each species, and analyzed the results.