A Survey of Small Mammals from Huu Lien Nature Reserve, Lang Son Province, Vietnam

Mammal Study 32: 155–168 (2007) © the Mammalogical Society of Japan A survey of small mammals from Huu Lien Nature Reserve, Lang Son Province, Vietnam Darrin P. Lunde1,*, Nguyen Truong Son2 and Guy G. Musser1 1 Department of Mammalogy, American Museum of Natural History, Central Park West @ 79th Street, New York, NY 10024 2 Department of Vertebrate Zoology, Institute of Ecology and Biological Resources, Vietnamese Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam Abstract. A survey of the small mammals of Huu Lien Nature Reserve, Lang Son Province, Vietnam (21°40'52''N, 106°20'28''E) resulted in the capture of 187 specimens representing 21 species of bat, insectivore, and rodent: Suncus etruscus, Rhinolophus pearsonii, Rhinolophus pusillus, Rhinolophus stheno microglobosus, Aselliscus stoliczkanus, Hipposideros armiger, Hipposideros larvatus, Harpiocephalus harpia, Pipistrellus paterculus, Scotomanes ornatus, Callosciurus erythraeus, Dremomys rufigenis, Niviventer fulvescens, Niviventer langbianis, Tonkinomys daovantieni, Rattus andamanensis, Rattus losea, Rattus tanezumi, Mus caroli, Rhizomys pruinosus, and Atherurus macrourus. In addition Ratufa bicolor and Tamiops sp. are reported from observations. The recently described genus and species Tonkinomys daovantieni is currently known only from material collected during the present survey and is apparently endemic to karst habitats in northeastern Vietnam. Key words: biodiversity, Huu Lien, mammals, Tonkinomys, Vietnam. Across the northeastern part of Vietnam extends a stun- resentative of the entire Viet Bac karst zone. The first ning landscape of forested limestone towers of the Viet efforts towards a comprehensive survey of the Huu Lien Bac karst zone (Tuyet 1998). Confined to Vietnam east mammal fauna were begun by the staff of the Institute of of the Red River, and extending into southern China, it is Ecology and Biological Resources (Can et al. 2000), the largest of at least five distinct limestone regions in which reported fifty-seven species of mostly large ani- Vietnam (Fig. 1). Despite its close proximity to Hanoi; mals based on interviews of local hunters. Additional the entire Viet Bac karst zone remains very poorly sur- surveys of bats were conducted in 1998 and 2000 veyed for small mammals. Delacour and Lowe passed (Hendrichsen et al. 2001; Son et al. 2004) but a de- through Bac Can and Lang Son Provinces in the winter tailed survey of rodents and shrews has been long out- of 1926–1927, but their expedition, focused as it was on standing. avian surveys, neglected the smaller terrestrial mammals In 2004 we surveyed small mammals from the tower so that little was added to our knowledge of these groups karst forests of Huu Lien Nature Reserve as part of an (Thomas 1928). It was only in the last years of the twen- effort to further document the fauna of this region. Our tieth century that comprehensive mammal surveys were specific goals were to: 1) fill a void in our understanding begun at the Huu Lien Nature Reserve. of the rodent and shrew fauna; 2) supplement the previ- Established in 1986 for the purpose of conserving ous surveys of bats; 3) specifically sample karst habitats limestone biodiversity and to protect the Musk deer, for endemic taxa; and, 4) establish an additional geo- Moschus berezovskii, the Huu Lien Nature Reserve is graphic reference point in a continuing effort by Lunde just 90 kilometers northeast of Hanoi and is accessible by towards eventually understanding the biogeography of a one-day car trip and a second day of hiking into the small mammals across all of northern Indochina. mountains. The reserve is an ideal site for implementing The location of our survey site is: Vietnam: Lang Son a mammal survey that could be regarded as broadly rep- Province; Huu Lung District; Huu Lien Commune; Huu *To whom correspondence should be addressed. E-mail: [email protected]. 156 Mammal Study 32 (2007) Fig. 2. Tower karst landscape typical of the Huu Lien Nature Reserve. Tropical moist deciduous forest covers the steep slopes, but the valley bottom has been cleared for agriculture. Photo by D. P. Lunde, April 2004. eroded limestone towers. The topography of the forest habitat was marked by sheer cliffs and limestone rubble (Figs. 2 & 4). There was abundant evidence of forest degradation as the local Dao villagers depend heavily on forest resources. Imperata grass (300–400) — A dense stand of tall Imperata grass. Bamboo forest — A thick stand of tall, hollow- stemmed bamboo and scattered trees. Continuing down the far side of the massif that was the focus of our study site we discovered an entirely deforested hillside of Fig. 1. Map of Vietnam showing five limestone regions recognized Imperata grass and swidden agriculture. by Tuyet (1998). The location of our study site in the Huu Lien Nature Reserve is indicated at 21°40'52''N, 106°20'28''E. Materials and methods Lien Nature Reserve; Lan Dat Village, 21°40'52''N, Fieldwork was continued for 20 consecutive days be- 106°20'28''E (Fig. 1). Trapping efforts were concen- ginning on April 6, 2004. Victor snap-traps, Sherman trated in several distinct habitats leading from our camp live traps, Tomahawk cage traps and Conibear traps were in a broad flat valley at 150 m elevation up to the top of used to trap small mammals (see Voss and Emmons an eroded karst tower at approximately 450 m elevation (1996) for descriptions of traps). Trapping efforts were (Fig. 2). Habitats sampled and their elevation range (in aimed at maximizing the number of species sampled, and parenthesis) are as follows: so in addition to setting traps on the ground, we tied Rice field (150 m) — A large expanse of fallow rice Victor and Conibear traps to woody vines to sample ar- fields occupying the relatively flat lowlands near the vil- boreal species. We also placed traps on elevated lime- lage (Fig. 2). At the time of our survey the fields were stone ledges and lowered them into caverns and cavities used for grazing small herds of buffalo. beneath limestone rubble. The type of trap employed Scrub (150–200 m) — A 30–70 m wide swath of and the length of time that a trap was allowed to remain scrub (grasses, shrubs, low secondary tree growth) defin- in one place depended on the experience of the trapper. ing the border between rice paddies in the valley and No attempts were made to standardize trapping effort evergreen forest on the karst slopes above (Fig. 3). but we did record the numbers, and kinds of traps set in Tropical moist deciduous forest (200–300) — moist different habitat types and these data are summarized in deciduous forest growing on the steep slopes of the Table 1. Traps were baited with a mixture of peanut Lunde et al., Small mammals in Vietnam 157 Fig. 3. A pitfall trapline in the dense scrub at the base of a karst Fig. 4. Tropical moist deciduous forest covering the steep slopes of tower. The only specimen captured in this line was a single Suncus a karst tower. Musser is seated near the entrance to a small cave-like etruscus, although several specimens of Niviventer fulvescens, Rattus structure where we captured specimens of Tonkinomys daovantieni, andamanensis, and Mus caroli were captured here using conventional Niviventer fulvescens, and Rattus andamanensis. Photo by D. P. traps. Photo by D. P. Lunde, April 2004. Lunde, April 2004. butter, oatmeal, raisins and bacon mixed in a 6 : 2 : 2 : 1 Liver samples were preserved in lysis buffer prior to ratio. In addition to conventional traps we also employed fixation. Skulls were extracted and cleaned from most pitfall-trap lines after a design depicted in Voss et al. specimens. Limits of standard external body measure- (2001); except our lines differed in the numbers of pit- ments (in mm) taken in the field are abbreviated: TL falls per line with one in secondary scrub consisting of (total length); T (tail length); HF (hind foot length); E 7 buckets along 40 meters of continuous drift fence (ear length); and FA (forearm length, bats only). Weight (Fig. 3), and a second in bamboo forest consisting of 19 was recorded in grams. Cranial measurements (in mm) buckets along 100 meters of continuous drift fence. Bats follow Bates and Harrison (1997) for bats, and Musser formed a secondary component of our survey and were (1979) for murid rodents. Specimens were cataloged in collected by providing mist nets to survey helpers from the American Museum of Natural History (AMNH) and Lan Dat village. will be eventually split with the Department of Zoology Specimens were fixed in formalin solution (3.75% at the Institute for Ecology and Biological Resources formaldehyde) and are now preserved in 70% ethanol. (IEBR). This paper is the sixth in a series on the small Table 1. Summary of trapping effort based on numbers of trap nights (a trap night is defined as one trap set for one night) per trap type and habitat type Victor Traps Sherman Traps Tomahawk Traps Conibear Traps Total trap nights Proportion of effort Scrub/Rice field 716 349 34 0 1099 26% Forest 2065 352 205 124 2746 65% Bamboo 200 0 47 0 247 6% Imerata grass 0 110 0 0 110 3% Total trap nights 2981 811 286 124 4202 100% Proportion of effort 71% 19% 7% 3% 100% – When expressed as a percentage of total trap nights it is clear that most of our sampling efforts were directed toward the forest habitat using Victor traps. Overall trap success is calculated at 2.9% based on 120 captures in 4202 trap-nights total. 158 Mammal Study 32 (2007) mammal fauna of Vietnam by Lunde and colleagues 4.4, anterior width of upper M2 1.3, length of M3 0.4.

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