field expeditions — Southwest cambodia

Click on a photo to view an enlarged image

Prey Nup mangroves

The Prey Nup mangroves were briefly flown over on the 22 October 2008, and were visited for part of one day on the 13 November 2008 by R. J. Timmins. The Prey Nup mangroves of the Prek Smach estuary were a minor survey site, and notes reported here are drawn up in comparison with finding from the rest of the survey. A ca. 700 ha block of mangroves on the southwestern, seaward edge of the Prek Smach estuary are under title by a concerned Cambodian businessman who, in partnership with entrepreneurial expatriate associates, wishes to maintain the integrity of the mangroves and develop the site for ecotourism and sustainable resource-use management by local communities.

From the northern edge of the Ream National Park (on the Prek Taek-sap estuary) stretches a relatively broad band of mangroves and rear-mangroves north to the Prek Smach estuary. Colonial era dykes separate this mangrove band from extensive areas of paddies that stretch inland to National Route # 4 and settlements that line the road. However, in various areas, especially north of the Prek Smach, there are areas of marsh and seasonally inundated grasslands interspersed with paddy land. The Prek Smach is a relatively small river with a reasonably extensive mangrove band surrounding the estuary. But above the Veal Rhen — Kampot road bridge there is little to no riparian forest remaining. Several large sedimentary formations in the Prek Smach (largely below the bridge) support seasonal rice agriculture.

This stretch of coast and the Prek Smach is one of the more heavily used areas in comparison to other parts of the coast surveyed further west. It has not be ascertained if there are any major developments planned for the area, but the numbers of people living in close proximity and the extent of agriculture, suggests land use will significantly intensify in the near future. It was somewhat surprising that the mangroves were still in reasonable condition and contiguous along the coast. However, there had been recent clearance of mangroves on the northeastern border of Ream NP, including some aquaculture development and apparently there is ongoing housing development on the adjacent hilly terrain (Kaoh Khyang — within Ream NP). If all of these threats are unchecked, it will likely break the continuity of the coastal mangrove strip.

The mangroves remain intact along the coast and in relatively good condition, equal to (and in places better than) the condition of those in Peam Krasop Wildlife Sanctuary, although somewhat more degraded in general than those in the northwest of Kampong Saom Bay. The coastal mangroves from Ream NP to the Prek Smach estuary, although lacking the richness of habitats present at some of the other surveyed sites (e.g., the area does not have extensive Melaleuca woodlands, grasslands, ‘upper’ riparian forests nor ‘black water’ swamps and marshes), still represent a significant area of mangroves at the national, if not also the regional level.

The 700 ha mangrove estate is at its ‘centre’ greater in width (i.e., perpendicular distance from sea to dyke) than most of the remaining coastal mangrove band. It has also better on average forest condition, than other sections of the coastal mangrove band and retains significant groves of mature trees (some sections of the coastal band are predominantly young secondary growth). These two factors make it one of two ‘core’ areas (the other being further south, closer to Ream) within this coastal mangrove band.

Detailed surveys are needed to fully quantify the biodiversity conservation significance of the coastal mangroves, but preliminary observations suggest the area is nationally significant for several species and possibly even globally. Storks are still widespread in Cambodia and are obviously common in the coastal strip between Ream NP and the Prek Smach. Of most significance are the observed numbers of Milky Stork (Globally Vulnerable) and Lesser Adjutant (Globally Vulnerable). It is not clear if these two species are non-breeding visitors from breeding colonies at Prek Toal on the Tonle Sap floodplain, but if they are coastal breeders, then the Lesser Adjutant population would be of notable national significant, whilst that of Milky Stork would be potentially of global significance. Understanding the seasonal movements of Milky Storks and determining if they breed along the coast is probably the highest wildlife research priority at present.

Otters also reportedly persist in these mangroves, and dependent on the species present, the population is likely to be of national, if not regionally, significant. If Hairy-nosed Otters (Globally Threatened — Endangered) persist, they are a high priority for protection and management and would give the site great conservation value.

Large fruit-bats (‘flyingfoxes’) Pteropus spp. also reportedly use the coastal strip seasonally for roosting. The two likely species, Large Flying-fox (Globally Near Threatened) and Lyle’s Flying-fox (Globally Vulnerable), are both at high risk nationally and any significant roost sites are automatically of national conservation significance.

Certain other observations suggest that this coastal strip has perhaps additional conservation value in comparison to other mangrove areas along the Cambodian coast, for instance significantly higher numbers of Brahminy Kites (Regionally At Risk) were observed in the area, compared with all the other survey sites further to the west. The environs of the Prek Smach, was the only survey site where Blue-tailed Bee-eaters were found (these birds were common there). Numbers of Lesser Whistling Duck, herons, egret and waders were relatively high; altogether suggesting a healthy avifauna remains in the area.