Evaluation of changes in vegetation cover on Guadalupe Island with vegetation indices

Detection of spatial and temporal changes in vegetation cover are essential for a better understanding of the state and abundance of resources in a region. This study focuses on the evaluation of the changes and the recovery of the vegetation cover of Guadalupe Island, affected by the presence of feral goats, eradicated in 2007. The change analysis was based on the calculation of the normalized difference vegetation index (NDVI) and soil adjusted vegetation index (SAVI), using high-resolution multispectral satellite images of the QuickBird and WorldView-2 satellites, from 2004 and 2013, corresponding to the stage before and after the eradication of goats, respectively. The change in the surface and the rate of change in the coverage of the plant communities were evaluated. According to the results obtained, the cypress, pine and palm forest cover were easily identified, with an increase in biomass for 2013. Similarly, it was found that the grassland doubled its surface coverage, and there was a decrease in bare soil for 2013. However, the NDVI had limitations in determining changes in scrub cover due to the low and medium density of vegetation for both years; therefore, the analysis of SAVI coverage was deepened, with better results and a sustained increase in post-eradication values. The changes indicate a recovery for almost all communities by 2013.

Automated summary

This study evaluates the changes and recovery of vegetation cover on Guadalupe Island using high-resolution satellite images, showing recovery for almost all plant communities post-goat eradication.