The Conservation Status of Phayre's Leaf Monkey Trachypithecus phayrei in Lao PDR

Phayre's leaf monkey Trachypithecus phayrei had fewer confirmed 1990s records in Lao PDR than any other monkey known from the country, suggesting a general rarity there. This review collates records, historical and recent, to evaluate its national conservation status. Although in no area have surveyors regularly and readily seen the species, records come from a wide scatter of areas in and north/west of Nam Kading National Protected Area to the far north and west of the country. There are inconclusive indications of occurrence up to 120 km south of confirmed records, but this part of the country is well enough surveyed that the animal must be very rare there, if it occurs at all. Much of North Lao PDR comprises ragged highlands over 800 m altitude, but only one Phayre's leaf monkey field record is from above this height (at 1,125 m). Whether this apparent altitudinal restriction is a natural pattern or reflects heavy hunting is unclear. Despite their lower-lying locations, records are not associated with gentle terrain. Most records come from forest with a heavily broken canopy and much tall bamboo; none is from deep within extensive closed-canopy forest. This might simply reflect the paucity of such forest within the known Lao geographic and altitudinal range, but a genuine habitat association with broken canopy and tall bamboo is likely. The status of Phayre's leaf monkey in Lao PDR is less grim than was feared a decade ago, and it inhabits three national protected areas, which are benefitting from long-term external collaboration. Nonetheless, its status in Lao PDR cannot yet be considered secure. Lao populations are probably relatively insignificant to the global status of T. phayrei as here taxonomically constituted.