Mangrove species distribution and abundance in relation to local environmental settings: a case-study at Tumpat, Kelantan Delta, east coast of peninsular Malaysia

We studied mangrove vegetation at Tumpat to estimate different tree structural parameters (e.g., stem density and basal area) at selected sites (PCQ method). There were five dominant taxa in the vegetation, i.e., Sonneratia caseolaris, Nypa fruticans, Avicennia alba, Rhizophora mucronata, and Bruguiera gymnorrhiza in order of importance. Total tree density varied between 79 and 132 stems 0.1 ha-1, and basal area from 0.14 to 4.9 m2 0.1 ha-1. Based on species composition and stem density, the mangrove sites were separable into two groups (Bray-Curtis similarity: 60%). While Group-1 (sites G9, J5, K4, N6 and O4), dominated by S. caseolaris and N. fruticans, was distributed throughout the forest, Group-2 (sites C6 and G6), represented largely by A. alba, was present close to the bay-mangrove boundary. Elevation measurements indicate that Group-1 species occupied low-lying to elevated grounds (0.87–2.23 m above mean sea level) with a (mean) salinity between 0.38 and 14.6 psu, whereas Group-2 occurred preferentially at low to medium elevations (0.86–1.29 m) and high salinity (14.6 psu). Discrete mangrove associations (=groupings) were discerned, wherein the distribution of species was governed by factors such as proximity of land or sea, freshwater input and elevation.