Adaptation of mangrove trees to different salinity areas in the Ayeyarwaddy Delta Coastal Zone, Myanmar

Abstract

Mangroves in the Ayeyarwaddy Coastal Delta Zone (ADCZ) of Myanmar are well known for their rich biodiversity and their enormous ecosystem services. However, as recently evident from the adverse impacts of Cyclone Nargis in 2008, they are increasingly threatened by the impacts of climate change and variability. This study was aimed to understand mangrove species composition and their characteristics driven by climate-related variables such as salinity. Transect survey method to investigate the species composition and mangrove quality including tree density, canopy height, and diameter at breast height and species distribution were used. The study was conducted during 2015–2017 in Laputta and Bogalay Townships of ADCZ. Individual transects of 500 m which included six sample plots of 15 m × 15 m along each transect line were investigated. Salinity was significantly higher in Laputta (14.4 ± 3.0 PSU in November - 28.8 ± 0.5 PSU in May) than in Bogalay (0.5 ± 0.2 PSU in November - 14.4 ± 3.0 PSU in May). Six species were confirmed to grown only in the high salinity area at Laputta. Nine species showed a preference for low salinity area at Bogalay. Among the thirty species, fifteen species were documented as the highest salt tolerant species as observed in both low and high salinity areas.