1999 Ngoc Linh
Biogeography & Conservation
In 1999, the joint Center for Biodiversity and Conservation at the American Museum of Natural History (CBC-AMNH), Institute for Ecology and Biological Resources (IEBR) and Missouri Botanical Garden (MBG) biotic inventory survey teams visited the Ngoc Linh Mountain Range in Quang Nam Province, central Vietnam. Ngoc Linh (2598m) is the second highest mountain in Vietnam and its associated peaks form part of the Kon Tum Plateau in the mountainous Western Highlands at the southern end of the Truong Son Range. The primary work site on the northeastern slope was chosen to complement previous and ongoing research focused on expanding the protected areas network in the region.
The Western Highlands represent the southern extension of the Truong Son Mountains into Vietnam, and they share the biogeographic and climatic factors which make the entire range a region of high species diversity and endemism. Geologic, topographic and climatic variation along this extended chain of mountains and drier lowland passes results in separate biodiversity and conservation significance for the different forested ecosystems. Ngoc Linh Range and the high altitude montane habitats of the Kon Tum Plateau fall within the distinct Central Annam Mountains (Ma) subunit of the Indochinese subregion. There are significant climatic differences between the northeast (Quang Nam) and southwest (Kon Tum) sides of the range. The southern and western exposures are subject to the southwest monsoon and are much drier with a distinct xerophytic component; the northern and eastern sides experience the northeastern monsoon, are more humid and have higher monthly and annual precipitation. The dominant vegetation type at all elevations is montane broadleaf evergreen forest; within this broad category forest types can be highly varied depending on local microclimates. Elfin cloud forest ("moss forest") is distributed along the high mountain ridge separating the two provinces. At medium and high elevations (above 1000m) families representative of a Sino-Himalayan flora are present, including the Fagaceae, Lauraceae, Magnoliaceae and Ericaceae. Small areas of mixed coniferous/evergreen forest contain the Vietnamese endemic Pinus dalatensis. Below 1000m, forest diversity is high with no one family dominant; species include Sino-Himalayan (Juglandaceae, Ulmaceae) and Malesian (Myrtaceae, Sterculiaceae) elements. A large number of montane passerine species and subspecies occur in the central Truong Son which are endemics or near-endemics to the region. Two new species have recently been described from Ngoc Linh, the Golden-Winged Laughingthrush Garrulax ngoclinhensis and the Black-Crowned Barwing Actinodurasodangorum. The Kon Tum Plateau has recently been designated one of four Endemic Bird Areas (EBAs) in Vietnam.
The subtropical montane forests of the Kon Tum Plateau are significant to national, regional and global conservation. High levels of floral and ornithological diversity are indicative of the biogeographical uniqueness of this sub-unit, especially the high altitude montane areas. The CBC's collaborative biotic surveys of the northeastern slope of Ngoc Linh (Quang Nam Province) were designed to increase basic understanding of multi-taxa diversity patterns in the region and to aid in conservation efforts. Currently the southwestern slopes (Kon Tum Province) of the Ngoc Linh range are incorporated in the Ngoc Linh Nature Reserve (NR). Extension of the nature reserve to include the northeastern slopes would greatly increase protection for this species-rich forested ecosystem. The expanded reserve area would be contiguous with Song Thanh-Dakpring Proposed NR, covering a combined 160,000ha of Vietnam in a continuous reserve chain abutting the Xe Sap National Biodiversity Conservation Area (NBCA) proposed extension in Lao PDR. Results from this survey were combined with research conducted by Birdlife International Vietnam, the Forestry Inventory Protection Institute (FIPI) in Hanoi, and the Royal Ontario Museum (ROM), in a feasibility study for the inclusion of Ngoc Linh (Quang Nam) in Vietnam's protected area system.
Collections and observations were made in forests, streams and rivers located on the northeastern flank of the Ngoc Linh Mountain Range in Tra My District, Quang Nam Province (15° 11' N, 108° 02' E). The dominant forest habitats on these slopes are lowland through montane broad-leaved evergreen communities, with deciduous components below 1000m and small mixed coniferous areas above 1000m. The dry season is short (February and March) and total annual rainfall exceeds 3500mm per year, with higher elevations experiencing heavier precipitation. Sino-Himalayan and Malesian tree families are intermixed and present at all altitudes. Up to approximately 900m (low montane forest) the habitat was heavily disturbed, with forests persisting only in ravines and steeper slopes. At higher elevations (medium and high montane forests) disturbance levels were lower and the canopy became increasingly closed. Surveys were carried out along an altitudinal range of 200-1650m, with sampling efforts focused at main work site elevations of 200m, 920-940m, 1100m and 1450m. Freshwater fishes were collected from the pools, backwaters, side streams and main waterways of four rivers in the Tra My District: Tranh, Nuoc Ta, Loo and Nam Nin. Stream bottom composition included rock, gravel, sand and mud. Disturbance of the waterways and surrounding vegetation varied between sites.
At each locality the specific work site locations and microhabitat sampling regimes varied between the taxa collected, and additional localities were sampled for some groups. Small mammal and bat surveys were carried out concurrently at the Ngoc Linh work sites by Dr. Judith Eger, Dr. Lorelie Mitchell and Burton Lim from the Royal Ontario Museum. A detailed list of taxa-specific work sites, methods and dates is included in the Biotic Survey Reports.
The 1999 arthropod survey team included Dr. David Grimaldi, Dr. Lee Herman, Dr. Eleanor Sterling, Christine A. Johnson, Tam C. Nguyen and Xin-Ping Wang from the American Museum of Natural History, New York, and Dr. Khuat Dang Long from the Institute of Ecology and Biological Resources, Hanoi.
Arthropod surveys were carried out March 11-April 16, 1999, in the foothills of the Ngoc Linh Range, Tra My District, Quang Nam Province (15° 11' N, 108° 02' E). Located on the Kon Tum plateau in Vietnam's central highlands, the area is contiguous to the southwest with an existing protected area, Ngoc Linh (Kon Tum) Nature Reserve. This field survey was part of a collaborative effort to assess the feasibility of establishing an adjacent protected area at Ngoc Linh (Quang Nam) (Tordoff, Tran & Tran, 2000). The proposed site is currently awaiting approval by the provincial people's committee and the central government (BirdLife, 2002).
Permanent passive traps and general collecting techniques were used at elevations of 700-1470m. Up to approximately 900m, the habitat was mostly degraded cultivated land with some forest persisting in ravines and on steeper slopes. These remnants were low montane broad-leaved evergreen forest with a diverse mixture of both Sino-Himalayan (Juglandaceae, Ulmaceae, Lauraceae) and Malesian (Myrtaceae, Sterculiaceae) species. At higher elevations the vegetation intergraded with medium montane broad-leaved evergreen forest. This habitat became increasingly dominant above 1000m and in general was typical of Vietnamese montane forests. The characteristic species were representative of Sino-Himalayan floral elements (Fagaceae, Lauraceae, Magnoliaceae) with some conifer species mixed in.
Additional small collections were made in highly degraded and agricultural habitats at 200m.
Methods and collecting protocols were designed to effectively sample focal taxa and the general terrestrial arthropod fauna, to provide an altitudinal distribution profile of Ngoc Linh's lower northeastern slopes, and to generate results for use in comparative analyses within and between survey locations.
Focal groups were chosen to provide a cross-section of arthropod biodiversity and to take advantage of AMNH and IEBR researchers' expertise. The following focal families were included in sampling protocols: Arachnida, Reduviidae (Heteroptera), Staphylinidae (Coleoptera), Vespidae and Braconidae (Hymenoptera), and Mycetophilidae and Drosophilidae (Diptera).
Collecting methods can be broadly classified as either permanent traps emptied at regular intervals or active collecting techniques. Coordinated house malaise traps and pitfall lines with drift fences were placed at four work site elevations: 950m, 1080m, 1290m and 1460m. Additional malaise traps were placed in suitable microhabitats at 830m and 920m. All permanent traps were emptied on a weekly basis and the majority were run for the duration of study. Nighttime collections using mercury vapor lamps and black lights were made near the 950m and 1460m work sites and at additional locations at 200m and 920m.
General collecting methods were used to sample arthropods around the four stationary trap work sites and in suitable microhabitats at elevations of 200m and 700-1470m. Active collecting techniques included sweep netting, aerial netting, and hand collecting.
Approximately 6,300 arthropod specimens were collected during the 1999 biotic surveys at Ngoc Linh. The materials have been cleaned, sorted to order, and the wet collections have been labeled. Focal group specimens in the Coleoptera, Diptera, Hymenoptera and Heteroptera have been removed for analysis by taxonomic specialists. Additionally, all specimens in the Reduviidae (Heteroptera) have been sorted, mounted and labeled. To process the large number of specimens collected during the three-year inventory project, the CBC has established a dedicated invertebrate preparation laboratory (for more information, please visit the Invertebrate Research Laboratory).
Analyses of these collections are still in the early stages and no additional information is currently available. Results, including identifications, descriptions, and information on species diversity and arthropod community structure, will be included as they are completed.
Literature Cited - Arthropod Research
BirdLife International. 2002. "Sourcebook of Existing and Proposed Protected Areas in Vietnam." Retrieved February 14, 2002 from BirdLife International Vietnam Programme web site: http://www.wing-wbsj.or.jp/~vietnam/source_book/index.htm. (Second edition: http://birdlifeindochina.org/birdlife/source_book/index.html)
Tordoff, A.W., Tran Hieu Minh and Tran Quang Ngoc. 2000. "A Feasibility Study for the Establishment of Ngoc Linh Nature Reserve, Quang Nam Province, Vietnam." BirdLife International Vietnam Programme, Hanoi.
Nguyen Quang Truong from the Institute of Ecology and Biological Resources, Hanoi, carried out the 1999 herpetofauna survey.
Specimens were collected March 10-April 2, 1999, at Ngoc Linh Range, Tra My District, Quang Nam Province (15° 11' N, 108° 02' E). This field survey was part of a collaborative effort to assess the feasibility of establishing a Nature Reserve at Ngoc Linh (Quang Nam) contiguous with the existing Ngoc Linh Nature Reserve in Kon Tum Province. Preliminary results from the CBC-AMNH/IEBR herpetofauna survey are included in "A feasibility study for the establishment of Ngoc Linh Nature Reserve, Quang Nam Province, Vietnam" (Tordoff, Tran & Tran, 2000).
Sampling efforts focused around four work sites at Ngoc Linh (Quang Nam): 1) Thon 2 Village, 920m; 2) Camp 1, 940m; 3) worksite, 1100m; and 4) Camp 2, 1460m. Sampling occurred in a variety of suitable microhabitats near these work sites and covered a total elevation range of 800-1500m. Up to approximately 1000m the habitat was mostly degraded cultivated land with some forest persisting in ravines and on steeper slopes. These remnants were low montane broad-leaved evergreen forest with a diverse mixture of both Sino-Himalayan (Juglandaceae, Ulmaceae, Lauraceae) and Malesian (Myrtaceae, Sterculiaceae) species. At higher elevations this forest type intergraded with medium montane broad-leaved evergreen forest, which became increasingly dominant above 1000m. The characteristic species were representative of Sino-Himalayan floral elements (Fagaceae, Lauraceae, Magnoliaceae) with some conifer species mixed in, and the habitat typical of Vietnamese montane forests above 1000m.
The primary sampling method was visual encounters during day and nighttime opportunistic collecting in appropriate microhabitats. The vast majority of specimens were obtained this way. Visual encounters included searches along streams, under rocks and logs, and within leaf litter. A small number of specimens (<10) were collected from pitfall trap lines established by the entomology survey team.
A total of 258 specimens were collected during the 1999 herpetofauna survey, representing 23 species and 5 families of amphibians and 11 species and 6 families of reptiles. All specimens were fixed in formalin and preserved in alcohol. Photographs and tissue samples for DNA analysis were collected from a sub-set of specimens. Approximately one-third of the alcohol-preserved specimens have been repatriated to the IEBR in Vietnam; the rest are currently housed in the collections of the Department of Herpetology at the AMNH. Additional specimens will be returned after identifications and descriptions are completed.
The Ngoc Linh survey recorded high levels of species diversity and endemism for the herpetofauna. Approximately 26% (6/23) of amphibians and 9% (1/11) of reptiles collected were endemic or restricted-range species. These elevated values may in part reflect patchy regional sampling efforts, which until recently have been poor in neighboring Lao PDR. Specimens collected included both northern (Ophryophryne microstoma, Paa spp.) and southern (Ophryophryne poilani, Rana milleti) Vietnamese elements, along with a number of widespread species (Leptolalax pelodytoides, Megophrys lateralis, all snake species). Range extensions were recorded for the megophryid frog Leptolalax tuberosus, the ranid frogs Amolops spinapectoralis and Rana attigua, the racophorid frog Rhacophorus exechopygus, and the anguid lizard Ophisaurus sokolovi (Bain & Nguyen, 2002a-d, in press). All five are restricted-range species and were previously known only from the Kon Tum Plateau in Gia Lai Province. Additionally, four species complexes were identified in the amphibian collections: Limnonectes blythii, Limnonectes kuhlii, Rana livida, and Polypedates leucomystax. These specimens may represent additional undescribed biodiversity at the site.
Despite these indications of high local biodiversity and endemism at Ngoc Linh, it is clear from literature and species accumulation curves that the current survey sampled a small sub-set of the actual herpetofauna in the region. Additionally, sampling was restricted to an elevation band of low- and mid-montane broad-leaved evergreen forest (the majority of specimens were collected at 850-1100m). Further sampling in both lowland and high montane forests and in additional microhabitats at Ngoc Linh would increase the number and diversity of species recorded.
The herpetofauna collections from Ngoc Linh are noteworthy for the high levels of species diversity and endemism recorded during a limited sampling period in one broad elevation zone. Highlights from the collections include high endemism rates for amphibians and reptiles, and species representing one rhacophorid and three ranid species complexes. New Quang Nam provincial records were recorded for four frog (Leptolalax tuberosus, Amolops spinapectoralis, Rana attigua, Racophorus exechopygus) and one lizard (Ophisaurus sokolovi) species. Seven of the 34 species collected remain unidentified (1 gecko, 6 amphibians); it is not clear how many of these are previously undescribed. We are currently working on identifications and possible new species descriptions for these taxa. A lacertid specimen collected at Ngoc Linh has been designated a paratype for the newly described grass lizard Takydromus hani (Chou, Nguyen & Pauwells, 2001) and is currently housed at the Institute for Ecology and Biological Resources, Hanoi.
Species with affinities to northern Vietnam and southern China and to southern Vietnam were collected during the survey. This overlap of northern sub-tropical and southern tropical faunas at mid-elevations parallels forest species diversity at Ngoc Linh. It is also consistent with the hypothesis that Vietnamese species diversity patterns are structured in part by the overlap of Sino-Himalayan and Indo-Malayan biogeographic zones. This apparent overlap of biota coupled with a relatively high number of endemic and restricted-range species indicates that Ngoc Linh should be considered a region of high amphibian and reptile biodiversity and subsequent conservation value. Further sampling, both locally and in adjacent regions of Vietnam and Lao PDR, will help refine this assessment.
Literature Cited - Herpetology Research
Bain, R.H., and Nguyen Quang Truong. 2002a. Geographic distribution. Rhacophorus exechopygus. Herpetological Review, 33:64.
Bain, R.H., and Nguyen Quang Truong. 2002b. Geographic distribution. Rana attigua. Herpetological Review, 33:63.
Bain, R.H., and Nguyen Quang Truong. 2002c. Geographic distribution. Amolops spinapectoralis. Herpetological Review, 33:61.
Bain, R.H., and Nguyen Quang Truong. 2002d. Geographic distribution. Ophisaurus sokolovi. Herpetological Review, 33:66.
Bain, R.H., and Nguyen Quang Truong. In press. Geographic distribution. Leptolalax tuberosus. Herpetological Review.
Chou, W.-H., Nguyen Quang Truong, and O.S.G. Pauwells. 2001. A new species of Takydromus (Reptilia: Lacertidae) from Vietnam. Herpetologica, 57:497-508.
Literature Cited - Amphibians and Reptiles Recorded During the 1999 CBC-AMNH/IEBR Biotic Inventory Survey
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The 1999 ichthyology survey team members were Radford Arrindell and Dr. Melanie L.J. Stiassny from the American Museum of Natural History, New York, and Le Hung Anh and Dr. Nguyen Xuan Huan from the Institute of Ecology and Biological Resources, Hanoi.
Freshwater fishes were collected in the spring of 1999 from four rivers in the Tra My District, Quang Nam Province (15° 14'-18' N; 108° 05-07' E): Tranh, Nuoc Ta, Loo and Nam Nin. Collection sites along the rivers included isolated pools, backwaters and small side streams with varied rock, gravel, sand and mud bottoms. Specimens were also purchased at five locations in Quang Nam Province: Tra My Market in Tra My District; Tam Ky Market in Tam Ky District; and Dong Da Hotel, Han River Market and Da Nang Market in Da Nang City.
A combination of dip nets, seine nets and overnight gill nets were employed at the collecting stations. Local Vietnamese assisting with the collections also used cast nets and hook-and-line. Rotenone was used at approximately one-third of the sites. Electro-shocking was not employed.
At each collection site a number of variables were recorded, including time, collection methods, water temperature and depth, and latitude and longitude, and brief site descriptions were noted. Photographs were taken of some specimens and worksites.
The 1999 freshwater ichthyology surveys in Quang Nam Province collected 947 specimens representing 97 taxa in 35 families from rivers in the Ngoc Linh Mountain range, and from markets in Tra My and Tam Ky Districts and Da Nang City. Captured and purchased fishes were fixed in 10% formalin and subsequently preserved in 75% ethanol. These specimens are currently housed in the collections of the Department of Ichthyology at the AMNH. Approximately half will be returned to Vietnam after identifications and descriptions are completed.
Specimens in these collections are currently identified to family, and analyses are ongoing. Preliminary results indicate that the majority of the taxa are in the Cyprinidae (minnow) family, consistent with previous survey work in Indochina and Southeast Asia. The freshwater fish fauna of Vietnam remains both under-surveyed and under-described, and identifications are complicated by the independent development of ichthyology in the region (Lundberg, et al., 2000). Additional results from these expeditions will be added as soon as they become available.
Literature Cited - Ichthyology Research
Lundberg, J.G., Kottelat, M., Smith, G.R., Stiassny, M.L.J., and Gill, A.C. 2000. So many fishes, so little time: an overview of recent ichthyological discovery in continental waters. Annals of the Missouri Botanical Gardens, 87: 26-62.
Literature Cited - Fishes Recorded During the 1999 CBC-AMNH/IEBR Biotic Inventory Survey
1. FishBase (compiler). 2001. "FishBase: A Global Information System on Fishes." Retrieved October 5, 2001 from FishBase: http://www.fishbase.org/home.htm
Mammalogy Research (Large Mammal Survey)
The 1999 mammalogy survey team members were Robert J. Timmins from the American Museum of Natural History, New York, and Trinh Viet Cuong from the Institute of Ecology and Biological Resources, Hanoi.
The survey was conducted April 22-May 24, 1999 at the Huong Son Forest, Huong Son District, Ha Tinh Province, located in the Northern Truong Son Mountains along the international border with Lao PDR (18° 15'-37' N; 105° 07'-17' E). Huong Son Forest is part of a trans-national complex of evergreen forests in the region, contiguous to the south with Vu Quang Nature Reserve (NR) in Vietnam, and to the west with Nakai-Nam Theun National Biodiversity Conservation Area (NBCA) in Lao PDR. This work was part of a larger field survey assessing the conservation value of the Huong Son Forest and is included in the summary report along with additional results (Timmins & Trinh, 2001).
The Huong Son Forest contains the headwaters of four rivers (Rao An, Nam Sot, Nam Mac and Song Con) and the primary vegetation along the valley bottoms and slopes is broad-leaved evergreen forest. Observations were made at elevations up to 1250m in four habitats: lowland valleys, lower slopes (150-500m), higher slopes (500-850m) and forests above 850m. Five main lowland valleys were visited: Rao An, Nga Doi, Nam Mac, Khe Tre and Song Con. The habitat in these areas was mostly degraded flat valley forest with tall secondary forest growth. In some areas (e.g., Rao An) the forest structure was fair to good, with trees of 20-30cm dbh present. Lower slope (150-500m) habitat quality varied with accessibility. At the upper ends of the valleys forest structure was good, with many mid-sized trees (20-35cm dbh), a closed canopy and healthy sapling growth; lower down the canopy was broken with fewer mid-sized trees, little evidence of regeneration, and many vines and bamboo. Higher up the slopes (500-850m) the forest was in good condition with only the largest trees removed. Large trees (>50cm dbh) were frequent and large fan-leafed ferns and cycads were characteristic of some areas. Habitat above 850m was surveyed only in the Rao An Tren Valley. The forests here were generally shorter and more open, with few large trees and some clumps of mid-sized bamboo. Ridges in this area were characterized by small bamboo species, ferns, rattan, and considerable herb ground cover.
The methods used to survey mammals in the Huong Son Forest were: diurnal searches, nocturnal spotlighting, camera-trapping and local interviews. Throughout the survey an emphasis was placed on recording large mammals and 'key species' considered important in national, regional and global conservation contexts. Observations of identifiable small mammals were also recorded and included in the results. Total survey effort was 29 person-days across all habitats and locations.
The primary method employed was opportunistic daytime searching and observation. Most observations were made while walking quietly along trails and during periods of static watching. Concentrated searches for mammal signs were conducted in the forest and along stretches of the Rao An and Nam Mac rivers. Night-time searches for nocturnal mammals were carried out at Rao An, Nga Doi and Nam Mac using headlamps (initial contact) and spotlights (identification). Seven camera traps were positioned in areas to maximize the likelihood of large mammal records. The receiver and transmitter were set 4-6m apart with the beam 15-30cm above ground and the camera set to incorporate this area up to a height of 50cm (where possible). Minimal emphasis was placed on interviews with local people and a systematic survey of villages and wildlife exploitation was not made. Efforts focused on locating remains in villages and contacting local wildlife dealers.
The mammal survey team positively identified a total of twenty-two species in twelve families and seven orders from the Huong Son Forest. Approximately one-third (8/22) of these are considered either Globally Threatened or Near Threatened: Sunda Pangolin Manis javanica, Bear Macaque Macaca arctoides, Douc Langur Pygathrix nemaeus, White-cheeked/Yellow-cheeked Crested Gibbon Hylobates leucogenys/gabriellae, Sun Bear Ursus malayanus, Owston's Civet Hemigalus owstoni, Saola Pseudoryx nghetinhensis, Southern Serow Naemorhedus sumatraensis and East Asian Porcupine Hystrix brachyura (after Hilton-Taylor, 2000). In addition, six species recorded have ranges limited to a subset of the Southern China and Indochina region: P. nemaeus, H. owstoni, Large-antlered Muntjac Muntiacus vuquangensis, P. nghetinhensis, Inornate Squirrel Callosciurus inornatus, and Annamite Striped Rabbit Nesolagus timminsi.
The large mammal fauna recorded at Huong Son is typical of the lowland and premontane broad-leaved evergreen habitats sampled and of known regional distribution patterns. The results also reinforce previously known or suspected faunal differences between the eastern and western slopes of the Truong Son Mountains. Two species recorded during the survey, H. owstoni and P. nghetinhensis, both have widespread records from Vietnam (east slope) but are only sporadically known from Lao PDR (west slope). The Truong Son Mountains are considered a center for regionally endemic flora and fauna, and there is evidence for this from the current survey. Among the species recorded was N. timminsi, a recently described lagomorph apparently restricted to the Truong Son Mountains along the Lao PDR-Vietnam border (Averianov, et al., 2000, Surridge, et al., 1989).
However, the large mammal fauna is clearly a sub-set of what would be expected from intact forests in this region. Most large mammal species were not common in their respective habitats, and there were no records of Bos, Elaphas, big cats and large deer and only limited signs, sightings or other evidence of diurnal primates, small carnivores and Muntiacus. This is in contrast with results from small mammal (1998/99) and ornithological (1999) surveys of Huong Son which found most species to be common in their respective habitats, with the exception of some larger quarry birds. In addition, the extensive small mammal survey found no evidence of human commensal species, indicating that the Huong Son Forest ecosystem is currently healthy and relatively undisturbed by human activities.
It probable that local hunting pressure is depressing the abundance of large mammals in the Huong Son. Snare lines were common throughout the forest. Trophies and recently killed small and large mammals were seen in the possession of villagers and local wildlife dealers. Additionally, there seems to be little evidence of buffering by mammal populations in adjacent Lao PDR forests as occurs elsewhere in this region of Vietnam. These two factors may be responsible for the reduced mammal populations, particularly those susceptible to hunting pressure. For example, only three out of seven diurnal primate species expected to occupy these habitats were observed and gibbon calling densities were extremely low given the extensive areas of good quality habitat still present.
Noteworthy findings from the 1999 survey at Huong Son Forest include evidence for a large mammal fauna characteristic of the eastern slopes of the Truong Son Mountains. Eight Globally Threatened and Near Threatened species were identified and six species with limited ranges recorded, including the probable regional endemics Owston's Civet Hemigalus owstoni, Saola Pseudoryx nghetinhensis and the recently described Annamite Striped Rabbit Nesolagus timminsi. The survey also found direct evidence that the abundance of these large mammals is currently depressed by intensive local hunting pressure.
Despite evidence of exploitation resulting in reduced population sizes and the absence of some expected species, Huong Son has potentially high conservation value in national, regional and global contexts. The forest is located in the northern section of the Truong Son Mountains, a low-lying range of hills and mountains along the Vietnam-Lao PDR border notable for the high species richness and endemic biota which the current study recorded. Additionally, Huong Son is part of a contiguously forested habitat block and there is evidence that the overall ecosystem is relatively healthy, with abundant bird and small mammal species and little evidence of commensal fauna. The combination of regional species diversity, the presence of threatened species and a relatively healthy and intact ecosystem confer high conservation value on this forest. Adding Huong Son to the regional network of protected areas would conserve biodiversity, increase habitat continuity and buffer wildlife exploitation throughout the region.
Literature Cited - Mammalogy Research (Large Mammal Survey)
Averianov, A. O., A. V. Abramov, and A. N. Tikhonov. 2000. A new species of Nesolagus (Lagomorpha, Leporidae) from Vietnam with osteological description. Contributions from the Zoological Institute, St. Petersburg, 3:1-22.
Hilton-Taylor, C (compiler). 2000. "2000 IUCN Red List of Threatened Species." International Union of the Conservation of Nature (IUCN), Gland and Cambridge.
Surridge, A. K., R. J. Timmins, G. M. Hewitt, and D. J. Bell. 1999. Striped rabbits in Southeast Asia. Nature, 400:726.
Timmins, R.J., and Trinh Viet Cuong. 2001. "An Assessment of the Conservation Importance of the Huong Son (Annamite) Forest, Ha Tinh Province, Vietnam, Based on the Results of a Field Survey for Large Mammals and Birds." Center for Biodiversity and Conservation at the American Museum of Natural History, New York.
Literature Cited - Mammals Recorded During the 1999 CBC-AMNH/IEBR Biotic Inventory Survey
1. Hilton-Taylor, C. (compiler). 2000. "2000 IUCN Red List of Threatened Species." International Union of the Conservation of Nature (IUCN), Gland, Switzerland and Cambridge, UK.
2. Corbet, G.B., and J.E. Hill. 1992. The Mammals of the Indomalayan Region: A Systematic Review. Oxford University Press, Oxford.
The 1999 ornithology survey team members were Dr. R. Terry Chesser, Ben F. King and Paul R. Sweet from the American Museum of Natural History, New York, and Dr. Le Dinh Thuy from the Institute of Ecology and Biological Resources, Hanoi.
The survey was conducted March 11-April 4, 1999, in the foothills of the Ngoc Linh Range, Tra My District, Quang Nam Province (15° 11' N, 108° 02' E), located on the Kon Tum plateau in Vietnam's central highlands. This field survey was part of a collaborative effort to assess the feasibility of establishing a Nature Reserve at Ngoc Linh (Quang Nam) contiguous with the existing Ngoc Linh Nature Reserve in Kon Tum Province. Preliminary results from the CBC-AMNH/IEBR ornithology survey are included in "A feasibility study for the establishment of Ngoc Linh Nature Reserve, Quang Nam Province, Vietnam" (Tordoff, Tran & Tran, 2000).
Collections and observations were made along an elevation transect of 200-1650m. Sampling was performed in various microhabitats at four altitudes: 200m, 920m, 1100m and 1450m. Up to approximately 900m the habitat was mostly degraded cultivated land with some forest persisting in ravines and on steeper slopes. These remnants were low montane broadleaf evergreen forest with a diverse mixture of both Sino-Himalayan (Juglandaceae, Ulmaceae, Lauraceae) and Malesian (Myrtaceae, Sterculiaceae) species. At higher elevations this forest type intergraded with medium montane broadleaf evergreen forest, which became increasingly dominant above 1000m. The characteristic species were representative of Sino-Himalayan floral elements (Fagaceae, Lauraceae, Magnoliaceae) with some conifer species mixed in, and the habitat typical of Vietnamese montane forests above 1000m.
Data were gathered through capture and direct observation. Specimens were collected using mist nets placed in microhabitats to maximize likelihood of capture, including ridge tops, gullies, slopes, forest gaps, and alongside and across streams. Direct observations were made in areas near mist net locations, and while walking into and out of the study site. Observational data was recorded daily and included both species identifications and estimated abundance.
A total of 146 species in 40 families were identified during the 1999 ornithological survey. Fifty-six species in 18 families were captured and139 species in 40 families were recorded by direct observation. Additional data on age, sex, degree of sub-cutaneous fat, molt, soft part colors, weight and breeding status were recorded. Specimens are currently housed in the collections of the Department of Ornithology at the AMNH; approximately half will be repatriated to the IEBR in Hanoi after identifications and descriptions are completed.
The 1999 ornithology survey recorded a rich avifauna with marked Sino-Himalayan affinities and a relatively high degree of localized biodiversity. The study site at Ngoc Linh is part of the Kon Tum Plateau Endemic Bird Area (EBA), and three of the seven restricted-range species known from this region were identified during the survey: Crested Argus Rheinardia ocellata, Yellow-billed Nuthatch Sitta solangiae and Black-hooded Laughingthrush Garrulax milleti. All three species are classified as either Globally Threatened (R. ocellata) or Near Threatened (S. solangiae, G. milleti) (after Stattersfield, Capper, and Dutson, 2000). Four species with ranges restricted to Vietnam, Lao PDR, Cambodia (east of the Mekong) and Southern China were also recorded: Red-vented Barbet Megalaima lagrandieri, Blue-rumped Pitta Pitta soror, White-winged Magpie Urocissa whiteheadi and Indochinese Green Magpie Cissa hypoleuca (after Robson, 2000).
Three other survey results suggest that the Ngoc Linh study site is an area of high local biodiversity. First, range extensions were recorded for a number of species. In general these were southward extensions of montane species known from the Truong Son Range and the highlands of northern Vietnam. Second, there is good evidence for differences in altitude distributions among closely related passerines which increases local species number (e.g., Black-browed Fulvetta Alcippe grotei and Mountain Fulvetta A. peracensis). Finally, information on migratory and breeding behavior collected during the survey will further elucidate regional biodiversity patterns.
Despite these results, the species recorded represent only a subset of those expected to occur at Ngoc Linh. Additional sampling, especially at higher elevations in the high montane evergreen, mixed coniferous and elfin forests, would likely increase recorded biodiversity.
Noteworthy findings from the 1999 ornithology survey at Ngoc Linh include records of three restricted-range species and four regional endemics and high levels of local avian biodiversity. Taxa observed and collected represent a number of new range extensions and we are currently working on analyses of these results.
Bird surveys in the central highlands have historically focused on and around the Da Lat plateau to the south, and biodiversity of the Kon Tum plateau (including Ngoc Linh) remains relatively understudied. Birds recorded from the eastern slope of Ngoc Linh include groups with geographic ranges generally extending either north or south from central Vietnam as well as those with more widespread, pan-Southeast Asian distributions. This overlap of northern and southern taxa increases species' richness and parallels observed patterns of both amphibian and tree species' diversity recorded at the site. Additionally, the presence of regional endemics indicates that the ecosystem has a strong component of localized biodiversity.
Ngoc Linh's conservation value arises from high biodiversity associated with overlapping northern and southern faunas, the presence of local endemics, and records of three Globally Threatened (Rheinardia ocellata) or Near Threatened (Sitta solangiae, Garrulax milleti) species from the survey. Recently published descriptions of two new bird species from Ngoc Linh (Kon Tum) (Golden-winged Laughingthrush Garrulax ngoclinhensis and Black-crowned Barwing Actinodura sodangorum) suggest that regional biodiversity may be underdescribed. Expanding the Ngoc Linh Nature Reserve to included the northern slopes would protect this species-rich ecosystem and add to a contiguous trans-national chain of proposed protected areas.
Literature Cited - Ornithology Research
Robson, C. 2000. A Guide to the Birds of Southeast Asia: Thailand, Peninsular Malaysia, Singapore, Myanmar, Laos, Vietnam, Cambodia. Princeton University Press, Princeton.
Stattersfield, A.J., D.R. Capper, and G.C.L. Dutson. 2000. Threatened Birds of the World: The Official Source for Birds on the IUCN Red List. BirdLife International, Cambridge.
Tordoff, A.W., Tran Hieu Minh and Tran Quang Ngoc. 2000. "A Feasibility Study for the Establishment of Ngoc Linh Nature Reserve, Quang Nam Province, Vietnam." BirdLife International Vietnam Programme, Hanoi, Vietnam.
Literature Cited - Birds Recorded During the 1999 CBC-AMNH/IEBR Biotic Inventory Survey
1. Stattersfield, A.J., D.R. Capper, and G.C.L. Dutson. 2000. Threatened Birds of the World: The Official Source for Birds on the IUCN Red List. BirdLife International, Cambridge.
2. Robinson, C. 2000. A Guide to the Birds of Southeast Asia: Thailand, Peninsular Malaysia, Singapore, Myammar, Laos, Vietnam, Cambodia. Princeton University Press, Princeton.