Artificial deepening of seasonal waterholes in eastern Cambodia: impact on water retention and use by large ungulates and waterbirds

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Thomas N.E. Gray
William J. McShea
Arnulf Koehncke
Prum Sovanna
Mark Wright


Natural seasonal waterholes (trapeang in Khmer) are an important feature of the deciduous dipterocarp forests of eastern Cambodia and are utilised by a number of globally threatened species of large ungulates and waterbirds. However at the end of the dry-season (April) only a small proportion of waterholes retain water. In 2011, we artificially deepened six waterholes in the core area of Mondulkiri Protected Forest, eastern Cambodia, removing 3m3 to 24m3 of earth (mean 16.5m3) from each.  Surveys prior to deepening demonstrated that only one of these waterholes, and 10% of all waterholes surveyed in the study area (n=50), held water at the end of the dry-season.  Following modification five of the six deepened waterholes (83%) held water at the end of the subsequent dry-season. From four camera traps over 448 trap-nights, 23 species including two globally threatened large ungulates, Banteng Bos javanicus and Eld’s Deer Rucervus eldii, and two Critically Endangered Ibises (Giant Thaumatibis gigantea and White-shouldered Ibis Pseudibis davisoni), were photographed foraging and drinking at the deepened waterholes between March and June 2012.  Our results suggest that artificial deepening of natural waterholes does not cause damage, and makes these waterholes suitable for use throughout the dry-season.  In the face of changing climate it is suggested that management plans should have a programme for the survey and determination of the status of waterholes every year and improve the use of water resources by artificial deepening.


Article Details

Author Biographies

Thomas N.E. Gray, WWF Greater Mekong, Conservation Strategy 3, House No. 39, Unit 05, Ban Saylom, Vientiane, Lao PDR

Thomas Gray is regional species manager for WWF Greater Mekong and has been conducting conservation research in Cambodia since 2005.


William J. McShea, Conservation Ecology Center, Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Rd., Front Royal, VA 22630 USA

William ‘Bill’ McShea is an ecologist who has worked at the National Zoo’s facility in Front Royal, Virginia, since 1986.  His research focuses on wildlife management and conservation of mammals and forests. 


Arnulf Koehncke, WWF Cambodia, #21, Street 322, Sangkat Beoung Keng Kang 1, Phnom Penh, Cambodia; WWF Germany, Reinhardtstr. 14, 10117 Berlin; Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Invalidenstr. 43, 10115 Berlin, Germany

Arnulf Koehncke was an intern supporting WWF Cambodia and currently works for WWF Germany


Prum Sovanna, Department of Wildlife and Biodiversity, Forestry Administration, Ministry of Agriculture Forestry and Fisheries, 40 Norodom Blvd, Phnom Penh, Cambodia

Prum Sovanna has worked in conservation for the government of Cambodia, and partner NGOs, since the mid 1990s and has led large mammal surveys across the country


Mark Wright, WWF Cambodia, #21, Street 322, Sangkat Beoung Keng Kang 1, Phnom Penh, Cambodia

Mark Wright was the landscape manager for WWF Cambodia’s Eastern Plains Landscape project.


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