Inventaire de Mare Longue (suite suite)

During the month of August, 2 Master students Sébastien Albert and Sohan Sauroy-Toucouère finished the measurements of the dbh of the trees.
Trunks were measured for woody plants > 4 cm diameter at breast height (dbh) in the one hectare plot in the forest of Mare Longue around 300 m above sea level.

Pix: Left, Sohan and Asplenium nidus var. nidus in the understorey. No day without rain during three weeks in the tropical rain forest, but no drop of rain mitigated our enthusiasm.

Dominance-diversity distribution for trees (dbh > 8 cm) was compared between 2005 and 2016 (Fig.1). With 36 species in 2016, 4 species have disappeared from the plot since 2005 : Pittosporum senacia, Cyathea excelsa, Memecylon confusum and the endangered Ochrosia borbonica.
The three most common species represent more than half of total trees. Labourdonnaisia calophylloides is more numerous in 2016 (362) than in 2005 (335). At the same time, Antirhea borbonica lost 40 trees, and this trend is stronger if we considered dbh > 4 cm (Fig.2). This species is the one which lost the most of stems (140) between 2005 and 2016, the second one is Chassalia corallioides which lost 69 stems. The important death-rate of the heliophilous species Antirhea borbonica is likely due to the canopy closure, while the shrub Chassalia corallioides shows a very important turnover with plenty of seedlings in the understorey.