J.G. Watson, Inundation Classes, and their Influence on Paradigms in Mangrove Forest Ecology

The influence of tidal inundation on mangrove vegetation species distribution is a key concept in mangrove ecology, and is especially important when considering the vulnerability of mangroves to predicted future sea level rise. While the tidal inundation-vegetation relationship defines a huge number of studies in mangrove science, it is not a new concept, but was mapped in the 1920s by scientists such as James Gilbert Watson, a forester with the colonial Forestry Department in Malaysia. Watson is particularly famous for his description of “Inundation Classes”, which described the flooding frequency at which different mangrove vegetation species could be found. It is interesting to consider how current paradigms and management practices (e.g. mangrove restoration) are shaped by the historical research that contributed to them. This article introduces JG Watson as a key figure in mangrove ecology, describes his seminal work on mangrove species distribution in peninsular Malaysia, and charts his legacy and contribution to current scientific debates surrounding physical controls on mangrove ecology. Importantly, research on tidal inundation and species distribution by Watson and others must be used correctly, including an acknowledgement that vegetation-inundation linkages are not universally applicable, and that species distribution is multi-factorial, and not dependent on inundation alone.