Warming's Impact on Bird Distributions in California

Authors: Carly Robbins*, Clark University, James Shute, NASA Center for Climate Simulation (NCCS), NASA Goddard Space Flight Center, Laura Carriere, NASA Center for Climate Simulation (NCCS), NASA Goddard Space Flight Center, Gerald Potter, NASA Center for Climate Simulation (NCCS), NASA Goddard Space Flight Center, Judy Hertz, NASA Center for Climate Simulation (NCCS), NASA Goddard Space Flight Center
Topics: Geographic Information Science and Systems, Biogeography
Keywords: GIS, species distribution, story map, Esri, ArcGIS, NASA
Session Type: Poster
Day: 4/4/2019
Start / End Time: 9:55 AM / 11:35 AM
Room: Lincoln 2, Marriott, Exhibition Level
Presentation File: Download


This study examines the effect of Earth’s rising temperatures on the species distributions of the migratory Hirundo rustica (barn swallow) in California between 1980 - 1997 and 1998 - 2017. We evaluated the change in bird distributions by applying spatial statistics such as the Getis-Ord Gi* statistic and Moran's I to measure geographic distributions and to detect and analyze spatial dependence of bird counts. In addition, we conducted a negative binomial regression to determine if monthly mean temperature could predict bird counts. Results indicated a northward shift in species distributions between the two time intervals. A comparison of barn swallow hot spot analysis maps revealed spatial clusters of high bird counts between 1998 - 2017 north of California, suggesting a change in environmental conditions that enabled these areas to support the two species. Negative binomial regression results showed that increases in monthly mean surface temperature would lead to increases in barn swallow counts and that temperature was a statistically significant predictor variable. However, inclusion of additional explanatory variables--climatic, biotic, land change, etc.--into the negative binomial regression models may improve results.

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