Dragonflies in the City: Diversity of Odonates in Urban Davao, Philippines

Abstract

Dragonflies are well-known group of insects because of their biological and ecological importance in a community, that is, they indicate the environmental health of an ecosystem. However, in an urban ecosystem, there are many threats that can affect the assemblages of dragonfly species such as the intensification of urbanization which contributes biodiversity loss of most dragonfly species. This study aimed to identify dragonfly species and determine the species richness, relative abundance, species diversity, evenness and effective number of dragonflies in selected areas in Davao City. Opportunistic sampling using sweep net and photo documentation were used during the study. The sampling lasted for three months from June 2017 to August 2017. A total of 962 individuals of dragonflies were observed and recorded comprising of six species of dragonflies from six different genera of one family. Orthethrum sabina was the most abundant among the six species recorded in all sampling sites. The species richness was six. Low species diversity was obtained in all sampling which shows that the sites were not evenly distributed and indicating that the study sites were not diverse in terms of the number of species and highly disturbed.