Hyperspectral remote sensing of salinity stress on red (Rhizophora mangle) and white (Laguncularia racemosa) mangroves on Galapagos Islands

Abstract

Mangroves are an assemblage of salt-tolerant woody hydrophytes that are the foundational species along tropical and subtropical coastlines, estuaries, lagoons and rivers. Once covering 75% of the world's tropical and subtropical coastlines, mangrove forests have been declining rapidly throughout the world in the last few decades. Monitoring and modelling mangrove forest growth are critical for their conservation. Salinity is one of the primary limiting factors for mangrove forest growth. In this letter, we report the potential of using hyperspectral remotely sensed data collected in the field for monitoring the photosynthesis rate of red (Rhizophora mangle) and white (Laguncularia racemosa) mangroves with regard to salinity gradient. Using photochemical reflectance index (PRI) as proxy for photosynthetic rate, PRI for both species are strongly related to salinity gradient, indicating the potential of monitoring mangrove forest growth on a regional scale using hyperspectral remote sensing.

Acknowledgement

The authors thank Dr. Sarah Lee, Kristin Blank, Evan Raczkowski, Stacey Frisk and Royce Brown for their field assistance, and the Galapagos National Park for providing transportation and a field guide. Funding for this pilot study was provided by the Center of Galapagos Studies at UNC, Chapel Hill, NC, USA.