Guwahati: In Assam, a key part of the Indo-Burma biodiversity hotspot, scientists report that despite rapid urbanization, deforestation, and agricultural expansion, there is no confirmed extinction or major loss of native leech species in the state so far.
However, experts caution that continued habitat degradation could pose long-term risks to these ecologically important invertebrates.
Recent surveys, including a detailed 2020 statewide assessment, documented both aquatic and terrestrial leeches across multiple districts. Researchers recorded five aquatic species along with common land leeches such as Haemadipsa sylvestris, which thrives in moist forested belts.
Nearly 2,000 specimens were collected during fieldwork, indicating a stable presence in suitable habitats, though abundance varies by season and locality.
Earlier molecular research conducted in Northeast India around 2018 expanded the known inventory of the region’s leech fauna.
Scientists identified genera such as Hirudinaria, Haemadipsa, Whitmania, and notably Myxobdella annandalae in yak-infested tracts. These findings added to biodiversity records rather than indicating declines or local extirpation.
No major post-2020 assessments have reported red-listing or species loss among Assam’s Hirudinea fauna. In broader biodiversity evaluations of Northeast India, leeches are seldom categorized as threatened; instead, they are often regarded as bio-indicators of freshwater quality and forest ecosystem health.
Nevertheless, indirect pressures remain a concern.
Expanding urban settlements, wetland reclamation, forest fragmentation, and the spread of invasive plant species are altering natural ecosystems. Such changes may gradually impact invertebrate communities, including leeches, even if immediate declines are not evident.
Ethnobotanical reviews also note that habitat shifts could erode traditional knowledge systems once used to manage leech infestations in rural areas.
Field observations further reveal that leech encounters remain common in Assam’s rural landscapes and forested zones, affecting humans and livestock alike, a sign of continued resilience in many pockets.
Ecologists say updated, targeted surveys using modern tools such as DNA barcoding are needed to detect subtle population shifts.
For now, Assam’s leeches, often overlooked yet ecologically significant, continue to survive quietly in wetlands and forests, even as the landscapes around them change.