Authors: Timothy Layton*, University of San Diego, Suzanné Walther, University of San Diego
Topics: Environmental Science
Keywords: stream, desert, riparian, landcover, change
Session Type: Virtual Paper
Start / End Time: 4:40 PM / 5:55 PM
Room: Virtual 46
Presentation File: No File Uploaded
Coyote Creek, a stream located in the largest watershed in Anza-Borrego Desert State Park (ABDSP), is intermittent most of its length, with sections of perennial flow. Though desert aquatic species are adapted to survive the extreme variability in precipitation characteristic of the southwest, these habitats show evidence of negative climate impacts. Changes in stream flow that result in fragmented pools and dry streambeds, can reduce freshwater aquatic invertebrate species richness and biological diversity. Vegetation along the stream also influences flow and, therefore, freshwater fauna. California experienced a drought in 2011-2016, altering vegetation cover in the creek. This study uses ArcGIS to quantify land cover changes between 2014, 2016, and 2018 on the Lower Willows section of Coyote Creek. To do so, we measured vegetation cover using the Normalized Difference Vegetation Index (NDVI) on 4-Band aerial imagery (USDA) of the study area. In two year, increments, we differenced the NDVI raster layer to quantify the changes in land cover over time. The resultant raster images were then re-classified into 5 categories highlighting gains, losses, and no change. NDVI successfully captured the vegetation distribution on Lower Willows, showing that vegetation cover increased between 2014-2016, particularly in the downstream half of the reach, but decreased between 2016-2018. Vegetation cover along streams can aid in retaining flow and desert aquatic species habitat, an important factor in arid lands management.