Reassessing the Conservation Status of an Island Endemic Frog
2016
Lehtinen, Richard M. | Calkins, Travis L. | Novick, Aaron M. | McQuigg, Jessica L.
Amphibians are among the most endangered organisms on Earth; however, few monitoring studies have been conducted in the tropics despite high amphibian diversity in these regions. To help fill this gap, we completed fieldwork to reassess the status of the Bloody Bay Poison Frog (Mannophryne olmonae, an endemic from the island of Tobago), classified as “Critically Endangered” by the original IUCN Global Amphibian Assessment, though recently downgraded to “Vulnerable.” To assess occupancy patterns and population stability, we used occupancy modeling with three years of listening survey data (2011–2013) from 35 sites. To examine patterns of relative abundance and recruitment, we gathered frog encounter rate and body size data from 18 stream-side transects. To assess current distributional limits, we conducted listening surveys at and beyond the known range limits. Together, these data suggest that M. olmonae is more widely distributed than previously reported (we found 23 extralimital populations), is present at a high percentage of sites surveyed (>70%), and is successfully reproducing along all of the stream-side transects on which they were found. Also, we found M. olmonae in a variety of forest types including both degraded secondary forest and abandoned cacao plantations. These field data were instrumental in downgrading this species and emphasize that species of conservation concern need to be monitored on the ground after listing, and these efforts must be continued to detect ongoing change. Our study suggests that even brief surveys in limited areas can quickly provide useful conservation data.
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