Assessing habitat associations of critically endangered big-headed turtles to support grassroots river conservation
Abstract
1. Modern biodiversity conservation relies largely on state-run protected areas and environmental regulations, whereas grassroots initiatives to protect species and ecosystems are underrecognized and receive limited scientific support. 2. We studied critically endangered big-headed turtles (Platysternon megacephalum) to support a grassroots river conservation initiative in Southeast Asia’s rapidly changing Mekong region. The study area was a montane watershed in northern Thailand, including an ambiguous protected area boundary, national forest reserve lands used and cultivated by local people, and a state-planned (currently suspended) large dam site. Residents have warned that the dam project could threaten the local wild-caught fishery and other freshwater biodiversity, including big-headed turtles, which have been encountered by fishers. 3. We aimed to provide the initiative’s leading village council and government-mandated authorities with current information on the turtle population to support species and ecosystem conservation. We trapped for turtles at 250 river and stream pools (494 trap-nights) above the planned dam site in 2024–2025 and assessed how species occurrence and observed body size varied with different pool features. 4. We captured 24 individual turtles (seven juveniles, four subadults, 13 adults) in 22 widely distributed river and stream pools inside and outside of the protected area, as close as ~400 meters to the planned dam reservoir. Species occurrence increased with pool width, depth, and boulder substrate (refugia). Body size was smaller in streams than in the river and correspondingly increased with water pH and decreased with forest canopy closure, possibly reflecting favorable conditions for nesting and/or juvenile survival in stream habitats. 5. Practical implication. Dam construction could diminish a breeding population of big-headed turtles by inundating parts of some turtles’ home ranges, blocking species dispersal, and/or disrupting river flow regimes and food webs. Hazardous irrigation (e.g. diversion of freshwater from turtle nesting areas) and fishing practices (e.g. electrofishing, use of explosives) observed by researchers inside and outside of the protected area could also threaten the turtle population. Amidst institutional fragmentation and ongoing land-use intensification and environmental degradation, grassroots initiatives to halt undesirable land development projects and improve local environmental management have key roles in protecting threatened species.
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BibTeX
@misc{herse2026assessing,
title = {{Assessing habitat associations of critically endangered big-headed turtles to support grassroots river conservation}},
author = {Mark Richard Herse and Wanlop Chutipong and Noppasorn Khuntong and Yik Hei Sung and George Andrew Gale},
howpublished = {EcoEvoRxiv},
year = {2026},
month = sep,
doi = {10.32942/x2d98g},
url = {https://ecoevorxiv.org/repository/view/14791/},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Assessing habitat associations of critically endangered big-headed turtles to support grassroots river conservation
AU - Mark Richard Herse
AU - Wanlop Chutipong
AU - Noppasorn Khuntong
AU - Yik Hei Sung
AU - George Andrew Gale
PY - 2026
DA - 2026/09/05
PB - EcoEvoRxiv
DO - 10.32942/x2d98g
UR - https://ecoevorxiv.org/repository/view/14791/
AB - 1. Modern biodiversity conservation relies largely on state-run protected areas and environmental regulations, whereas grassroots initiatives to protect species and ecosystems are underrecognized and receive limited scientific support. 2. We studied critically endangered big-headed turtles (Platysternon megacephalum) to support a grassroots river conservation initiative in Southeast Asia’s rapidly changing Mekong region. The study area was a montane watershed in northern Thailand, including an ambiguous protected area boundary, national forest reserve lands used and cultivated by local people, and a state-planned (currently suspended) large dam site. Residents have warned that the dam project could threaten the local wild-caught fishery and other freshwater biodiversity, including big-headed turtles, which have been encountered by fishers. 3. We aimed to provide the initiative’s leading village council and government-mandated authorities with current information on the turtle population to support species and ecosystem conservation. We trapped for turtles at 250 river and stream pools (494 trap-nights) above the planned dam site in 2024–2025 and assessed how species occurrence and observed body size varied with different pool features. 4. We captured 24 individual turtles (seven juveniles, four subadults, 13 adults) in 22 widely distributed river and stream pools inside and outside of the protected area, as close as ~400 meters to the planned dam reservoir. Species occurrence increased with pool width, depth, and boulder substrate (refugia). Body size was smaller in streams than in the river and correspondingly increased with water pH and decreased with forest canopy closure, possibly reflecting favorable conditions for nesting and/or juvenile survival in stream habitats. 5. Practical implication. Dam construction could diminish a breeding population of big-headed turtles by inundating parts of some turtles’ home ranges, blocking species dispersal, and/or disrupting river flow regimes and food webs. Hazardous irrigation (e.g. diversion of freshwater from turtle nesting areas) and fishing practices (e.g. electrofishing, use of explosives) observed by researchers inside and outside of the protected area could also threaten the turtle population. Amidst institutional fragmentation and ongoing land-use intensification and environmental degradation, grassroots initiatives to halt undesirable land development projects and improve local environmental management have key roles in protecting threatened species.
ER -