Records of Odonata in the Riparian System of Andanan Watershed Forest Reserve, Philippines

Abstract

The Odonata fauna is a good biological indicator of freshwater ecosystems. This research aims to provide a record inventory of both dragonflies and damselflies occurring in the riparian ecosystem of Andanan Watershed Forest Reserve. Field collection using sweep nets was done in three locations along the riparian area. Odonatans (n=79) were recorded belonging to 19 species, comprising 58% dragonflies and 42% damselflies. Out of 19 species recorded in the area, one species of dragonfly and six species of damselfly are endemic to the Philippines, with 36.84% endemicity in the area. All dragonflies documented are ground skimmers with a high tolerance for anthropogenic disturbances in freshwater systems. The genus Orthetrum Newman, 1833 is relatively abundant and obtained the highest number of species. On the other hand, the genus Euphaea Selys, 1840 in damselflies, was recorded to have the highest abundance. The genus Risiocnemis Cowley, 1934 has the highest species richness. All species of Risiocnemis were also reported endemic. Despite the high diversity (H’=2.77; H'/H_max=0.94) of the Odonata fauna in Andanan Watershed Forest Reserve, human activities and intervention were still observed around the riparian ecosystem. The results shown in the current study may be utilized as primary information to allow local conservation efforts for odonatans found in the watershed and its tributaries.