Description
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 perineal surface 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 focused on the Lower Willows section of Coyote Creek with the goal of quantifying the land cover changes between 2014, 2016, and 2018 using ArcGIS. Using 4-Band aerial imagery (USDA) clipped to the study area, analysis consisted of running Normalized Difference Vegetation Index (NDVI) to measure vegetation cover. To quantify the changes in land cover over time, in two-year increments, the raster calculator tool subtracts the older data set from the newer one. This creates a new raster image of the differences that were then re-classified into 5 categories highlighting gains, losses, and no change. NDVI successfully captured the vegetation distribution on Lower Willows, showing that vegetative land cover increased between 2014-2016, particularly in the downstream half of the reach, but decreased between 2016-2018. Vegetation cover in streams aids in retaining flow and desert aquatic species habitat, an important factor in arid lands conservation and management.
Land Cover Change on Coyote Creek, Anza-Borrego Desert State Park
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 perineal surface 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 focused on the Lower Willows section of Coyote Creek with the goal of quantifying the land cover changes between 2014, 2016, and 2018 using ArcGIS. Using 4-Band aerial imagery (USDA) clipped to the study area, analysis consisted of running Normalized Difference Vegetation Index (NDVI) to measure vegetation cover. To quantify the changes in land cover over time, in two-year increments, the raster calculator tool subtracts the older data set from the newer one. This creates a new raster image of the differences that were then re-classified into 5 categories highlighting gains, losses, and no change. NDVI successfully captured the vegetation distribution on Lower Willows, showing that vegetative land cover increased between 2014-2016, particularly in the downstream half of the reach, but decreased between 2016-2018. Vegetation cover in streams aids in retaining flow and desert aquatic species habitat, an important factor in arid lands conservation and management.