Wildlife of Lao PDR: 1999 Status Report - IUCN

Zoogeographic Relationships
Lao PDR is situated in the Indochinese subdivision (sensu
Corbet and Hill 1992) of the Indomalayan Realm (Fig. 3).
Within this subdivision, MacKinnon and MacKinnon (1986)
considered that Lao PDR contained parts of four
biogeographic units. Their unit of ‘Annam’ encompasses the
Annamite Range and extends across Vietnam to the South
China Sea. The other three zones are sub-units of ‘central
Indochina’: the ‘tropical lowlands’, the ‘tropical montane’
and the ‘sub-tropical transition zone’. These are shared with
Cambodia, Thailand, Myanmar, Vietnam and China. The
Indochinese fauna includes species shared with the Himalayan
Palaearctic (in the northern mountainous part of the region),
with the Chinese Palaearctic (species that have spread along
the coast of southern China), with the Sundaic subregion to
the south, and with northern India through the Assam-Burma
transition zone (MacKinnon and MacKinnon 1986). The
Annamite Range and the Mekong River are the main natural
barriers in the area, forming the limits of the range of a number
of species and subspecies.
Figure 3. Biogeographic context of Lao PDR.
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Introduction
Geographical Subdivisions of Lao PDR
King et al. (1975) divided Lao PDR into three geographical
subdivisions, north, centre and south. These lines were
drawn following direct correspondence with J. Delacour (E.
C. Dickinson in litt. 1999), who, with P. Jabouille (1931, 1940)
discussed the geographical distribution of birds in Lao PDR.
They made frequent reference to ‘haut’, ‘moyen’ and ‘bas’
Laos, but no formal system was defined. Other historical
authors did not always follow their guidelines: for example,
Bangs and Van Tyne (1931: 33) refer to Vientiane as lying in
“southern Laos” (see also Dickinson 1970b: 481). King et
al. (1975) provided sketchy textual definitions of the boundaries’
locations, and a very small map. Thus, at the resurgence
of wildlife fieldwork in Lao PDR in the late 1980s, the most
appropriate precise divisions for use on the ground were unclear.
Thewlis et al. (1996, 1998) therefore set boundaries
precisely, as follows: the south-central boundary follows the
Xe Banghiang river from its confluence with the Mekong
upstream to Xe Pon and thence along the southernmost major
affluent (the Xe Pon river) to the Vietnamese border at Lao
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Indomalayan Realm
Indochinese Subregion
Lao PDR
Source: Corbet and Hill (1992)
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