Vegetation indices for Pontederia crassipes Pellegrini & Horn and multitemporal distribution in the Hydroituango reservoir•

Abstract

Pontederia crassipes Pellegrini & Horn (water hyacinth) is an invasive, world-wide distributed aquatic plant, which has been evinced in the reservoir of the Ituango Hydroelectric Project - IHP (Colombia) since 2018. In this study, the ability of several Vegetation Indices (VIs) to detect P. crassipes was evaluated based on monthly Sentinel-2 images, between September 2018 and March 2020. The invasive capacity of P. crassipes was demonstrated with covered area doubling each month in the IHP reservoir. A maximum 32-fold increase of P. crassipes in just one month was registered during the rainy season and resulted in a 104-ha expansion. Results based on Cl red edge, MSR, and DVI were consistent and had less deviations from normality. Our results highlight the importance of new-generation sensors to discriminate and map the spatial distribution of P. crassipes for the development of efficient monitoring and management strategies at the reservoir scale.