Herpetological Assemblages in Tropical Forests of the Taguibo Watershed, Butuan City, Eastern Mindanao, Philippines

Abstract

Tropical watershed ecosystems support heterogeneous habitats and diverse non-human species assemblages, together providing ecosystem services to humans. Amphibians and reptiles are recognized as sensitive indicators of ecosystem “health,” related to beneficial services (provisional, regulating, cultural, structural, functional) human societies receive from terrestrial watersheds. The Taguibo Watershed supplies fresh drinking water to Butuan City in the Caraga Region of northeast Mindanao Island. However, very little is known about the herpetofauna of the area. Here, we synthesize biodiversity data from historical (1971, 1979) and recent (2013, 2017) herpetological surveys from the region. We utilize specimen-associated occurrence records and natural history information to produce a species inventory, analyze their habitat utilization, and characterize diversity metrics to describe herpetological communities of the watershed – resulting in 44 species (27 new records). A number of historically-documented species persist, having partitioned riparian and terrestrial habitat types in dipterocarp and secondary-growth forests of Taguibo. Reptiles exhibit little overlap in the use of microhabitats – in contrast to amphibians, which exhibit either unique or frequently shared microhabitat substrates. In terrestrial microhabitats (not immediately associated with water), many newly-recorded reptiles and amphibians (particularly, of the genus Platymantis) partition space predictably – either occupying a single microhabitat or, in one species (a pit viper, Tropidolaemus subannulatus), two microhabitats. We anticipate that our initial characterization of Taguibo’s herpetofauna may serve as a baseline to promote further research and facilitate conservation initiatives. We emphasize the importance of primary sources – field-based surveys and re-surveys – and open-access biodiversity data served via online platforms that provide live, transparent access to original, unaltered data. Anthropogenic threats involving economic-driven activities present a need for field-based research in support of watershed management. Periodic, survey, and re-survey studies – continuously updating earlier work – are the most reliable, repeatable, and publicly-transparent use of biodiversity survey data in support of societal benefits and ecosystem services.