Terrestrial Leech Ecology
This research explored the ecological roles and biomonitoring potential of terrestrial leeches in tropical rainforests. FIrst, we analyzed over five years of survey data to model the spatial distributions of two sympatric leech species at Gunung Palung National Park, West Kalimantan, Indonesia, revealing distinct elevational and moisture-related preferences between species. A second study integrated leech survey data with camera trap records of 32 terrestrial mammal taxa to evaluate the reliability of leeches as proxies for mammal abundance. Together, these studies advance understanding of leech ecology and assess their potential as a low-cost, scalable tool for tropical biodiversity monitoring.
Two species of terrestrial leeches inhabit the tropical rainforests of Gunung Palung National Park in Indonesian Borneo: the tiger leech (left), with it's characteristic stripe and painful bite, and the brown leech (right). Both feed on blood and are most active during rainy periods.
Our first leech publication focused on the ecological distribution of both leech species. Using more than five years of survey data, we found that the tiger leech (Haemadipsa picta) is most abundant in the lower-elevation forest types at GPNP, while the brown leech (H. zeylanica) is more common in higher-elevation forests.
Our second study investigated whether leeches could serve as indicators of mammal abundance. Using camera trap data collected over the same five-year period as our leech surveys at GPNP, we modeled leeches as predictors of mammal counts and found that, overall, higher leech abundance was associated with lower mammal detections.
However, for certain mammal taxa, this relationship shifts during the wettest periods, as shown above. These results suggest that leeches can act as conditional indicators of some mammal species, primarily during periods of high rainfall when leeches are most active.