Fern Diversity in Primary and Secondary Forests of Danum Valley and Ulu Segama Forest Complex, Lahad Datu, Sabah

Due to the depletion of primary forests, secondary forests are becoming
\nimportant to sustain biodiversity. Ferns are good indicators for forest quality
\nas many species have specific ecological preferences. The aim of this study
\nis to compare the diversity and composition of fern species between lowland
\nprimary and secondary forests. Secondary forests caused by logging
\nactivities are classified into secondary forest of high biomass and low
\nbiomass. Eight plots of 20 m × 20 m (400 m2
\n) were established in each
\nforest type totaling to 24 plots. Twenty-six species of ferns belonging to 11
\nfamilies were identified. Out of this, one species is new to Danum Valley
\nwhich is Leptochilus cf. decurrens. Shannon-Wiener Index showed that
\nsecondary forest of high biomass (H’=2.49) have high species richness than
\nprimary forest (H’=2.03) and secondary forest of low biomass (H’= 2.07).
\nSimilarity Index was used to compare the diversity of three forest types and
\ncluster analysis was used to show the grouping of the different forest types
\nby using PAST (Paleontological Statistics) version 2.17. Secondary forest
\nof high and low biomass showed high similarities. Higher species richness
\nof ferns in the secondary forest of high biomass is due to the presence of
\nmany light demanding fern species. Thus, canopy opening may have
\ninfluence the species diversity of ferns in secondary forests.