Pteridophyte Diversity in the Samar Island Natural Park (SINP), Samar Island, Philippines

Despite major efforts over the last 100 years assembling notable large amounts of information concerning the rich fern and lycophyte diversity of the Philippines, we still lack records for many areas including localities selected to protect biodiversity. Addressing the major gaps in our knowledge about the current distribution of plants in the Philippines is a crucial step towards the implementation of effective protection measurements to halter the ongoing biodiversity crisis. This study has been conducted to assemble a checklist of ferns and lycophytes occurring in the forests over limestone in Paranas, Samar Island Natural Park (SINP), Philippines. The Samar Island is of special interest not only to studies aiming to reconstruct the history of plants in the Philippines but also to our efforts to conserve this diversity in the Anthropocene. By field investigations in a series of transect walks and in combination with published fern records from online resources, a total of 139 fern species belonging to 59 genera and from 22 families were documented. About 18.7% of the recorded species were endemic to the Philippines. Two species Tectaria macleanii (Copel.) S.Y.Dong and T. psomiocarpa S.Y.Dong were considered to be endangered whereas Taenitis cordata (Gaudich.) Holttum and Pyrossia splendens (C.Presl) Ching were listed as vulnerable in the Philippines. This study provided the first comprehensive checklist of the fern and lycophyte diversity that has been protected in this natural park. However, we want to stress that further field exploration is required to improve our understanding of the fern and lycophyte diversity in the less explored parts of the Samar Island. Given the occurrences of several species with rather restricted occurrences including endemics, our study emphasizes the high value of the SINP to preserve the Philippine’s plant diversity.