Inferring Zonation in Mangrove Ecosystem via Leaf Size Indices in Rhizophora apiculata Blume

The present study intends to establish the relationship between the leaf size indices of Rhizophora apiculata relative to the zonation of the mangrove ecosystem in Masapelid Island. A transect line with 20 meters width and 160 meters length was established from the sandy soils up to the seaward zone of the forest. The transect was further subdivided into zones based on the typical species zonation patterns with the first zone covering 20 meters from the shore comprising the landward; the second zone considered as the middle covers from >20 to 60 meters while the third zone was the seaward zone includes >60 meters up to where mangrove species still exist. The leaves in every first branch of these species were collected in each zone to determine the variables such as length, width, thickness, and area. Collected samples then undergo tissue analysis to determine the nutrient status. The result shows that except for leaf thickness, a negative correlation between the zones was observed. This implies that the leaf length, area, and width decreases towards the seaward zone. In contrary, the leaf thickness showed a positive correlation which would mean increasing leaf thickness towards the seaward. Moreover, the leaf length and area were negatively correlated to nitrogen and phosphorus which implies that increasing amounts would lead to lower length and area while K has an opposite effect. Despite the seemingly decreasing trend observed,however, LSI, in this case,could not be the reliable indicator to demarcate zonations in the mangrove ecosystem