1998/1999 Northern Troung Son
Biogeography & Conservation
In 1998, 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, focused their primary collecting efforts within the Huong Son Forest Enterprises, Ha Tinh Province, in north-central Vietnam. Additional satellite sites at Ke Bo (Nghe An Province) and Cha Lo (Quang Binh Province) were less intensively surveyed. The Truong Son Mountain Range runs for approximately 1200km along the Vietnam-Lao PDR border and into south-central Vietnam. A complex history of geological uplifting and folding in this region has created a large, topographically diverse assemblage of limestone and granite formations, with a central ridge rising over 1000m interspersed with low passes. Field sites were selected to provide diverse samples from roughly the geographic center of the Truong Son Range.
Two factors contribute to the high biodiversity and conservation value of this region. First, the overlap of Sino-Himalayan and Indo-Malayan biotic influences creates a zone of high diversity. A
unique transitional flora combines northerly, subtropical plant families (e.g., Ericaceae, Fagaceae, Lauraceae and Magnoliaceae) with the Dipterocarpaceae of the tropical south. Unusual juxtapositions of these floral elements occur in which Ericaceae and Fagaceae are intermixed with palms and Dipterocarpaceae in lowland forest; transitions to montane forests are associated with altitudinal variation in the mixture of the two biotas. Second, both climatic and historical factors have contributed to high rates of endemism in the Truong Son. The eastern flank in Vietnam experiences a relatively stable and wet climate for much of the year (average annual rainfall 3000mm); to the west in Lao PDR, drier southwesterly winds result in a more marked and severe dry season. These climatic differences are associated with a suite of species whose distributions are limited to the eastern slopes and lowlands. Historically, the Truong Son Mountains are postulated to have provided stable refugia for forest-dwelling species during the dry periods of the Pleistocene glaciations. This long-term climatic stability is thought to have contributed to the high rates of local endemism in these regions.
The high species diversity and endemism of this endangered forest ecosystem makes it a priority for continued conservation and research efforts. The Huong Son Forest is a critical link in a chain of current and proposed protected areas in the Northern Truong Son Range, linking northern and central reserves. It is contiguous with the established Vu Quang Nature Reserve (NR) in Vietnam and the Nakai-Nam Theun National Biodiversity Conservation Area (NBCA) and its proposed northern extension in Lao PDR. Preservation of this forested region will consolidate the existing protected area network in this region and help maintain continuity of forest communities along the Truong Son spine.
The primary study area in the Northern Truong Son Range was located in the watershed of the An River within Huong Son Forest, Ha Tinh Province (18° 15'-37' N, 105° 07'-17' E). The forests are predominantly lowland through premontane broad-leaved evergreens with additional components mixed in (e.g., conifers, bamboo, cycads). Both secondary and primary forests are present and disturbance level varies with accessibility and topography along the river valleys. The primary collecting locations for terrestrial organisms and plants were located along an altitudinal range of 220-1270m. Sampling efforts focused on five main work sites:
- Riparian and seasonally inundated floodplain lowland evergreen forest along the An River and its tributaries, elevation 220-230m.
- Disturbed secondary lowland evergreen forest, elevation 250m. This habitat lay above the level of average seasonal inundation and had been heavily degraded by shrub and sapling harvesting.
- Lowland to premontane broad-leaved evergreen forest, elevation 250-1000m. The forest canopy along these hillside slopes was closed, and fern and cycads were present in some areas. The habitats sampled included sites along ridges and well-drained slopes. Collections focused at 680m and 920m.
- Premontane mixed broad-leaved evergreen coniferous forests, elevation 1000-1270m. The habitat was disturbed primary forest with a more open structure and dense understory of dwarf bamboo at higher elevations (1150-1270m). Collections focused at 1250m.
Aquatic vertebrates and invertebrates were sampled from the An River and its tributaries in the watershed. Streams were rocky and granite-bottomed, and lowland and premontane forests generally extended to the banks.
Additional collections of amphibians, reptiles and freshwater fishes were made at two lowland sites in the Northern Truong Son Range. The first satellite work site was located in and around Ke Bu Commune in Con Cuong District, Nghe An Province (19° 02' N, 104° 42' E). The vegetation was heavily disturbed secondary forests and scrub, elevation 200-300m. The second work site at Cha Lo in Minh Hoa District, Quang Binh Province (17° 42' N, 105° 45' E) was situated in minimally disturbed closed broad-leaved evergreen forests, elevation 250-400m. Streams at this location were granite-bottomed with medium to high gradients.
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. Limited survey work was undertaken at Huong Son Forest in 1999. A detailed list of taxa-specific work sites, methods and dates is included in the Biotic Survey Reports.
The 1998 arthropod survey team included Dr. James M. Carpenter, Dr. David Grimaldi, Dr. Lee Herman, Dr. Diana Silva and Cal Snyder from the American Museum of Natural History, New York, and Dr. Khuat Dang Long from the Institute of Ecology and Biological Resources, Hanoi.
Collections were made over a period of approximately seven weeks in April and May, 1998, at three localities in the northern Truong Son Mountains of north-central Vietnam.
The primary work site was located in the watershed of the An River, Huong Son District, Ha Tinh Province (18° 22' N, 105° 13' 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. At Rao An, sampling occurred over a six-week period, April 10-May 25, along an altitudinal range of 220-1270m. Permanent, passive collection methods (e.g., malaise traps) were deployed at four main elevations and associated habitats along this transect: 1) 220m, seasonally inundated flood plain and riverine evergreen forest; 2) 650m, well-drained closed canopy broad-leaved evergreen forest, located in a saddle along a ridgeline; 3) 920m, moist premontane closed canopy broad-leaved evergreen forest; and 4) 1240m, disturbed primary premontane mixed conifer and broad-leaved evergreen forest with a dense dwarf bamboo understory. Active collection techniques (e.g., sweep netting) and supplementary traps were both used at additional elevations and in suitable microhabitats (e.g., light gaps) along the transect. Aquatic invertebrates were collected from the An River and tributaries in part to examine water quality in the watershed.
Additional surveys were made at two satellite sites in neighboring provinces: Cha Lo, Minh Hoa District, Quang Binh Province (17° 42' N, 105° 45' E), and a number of localities in Con Cuong District, Nghe An Province (19° 02' N, 104° 42' E). Collections at these locations were more limited in scope (e.g., methods used) and duration, and all sampling occurred at elevations below 400m. At Cha Lo, collections were made in minimally disturbed, closed-canopy lowland broad-leaved evergreen forest at elevations of 250-400m. Habitats sampled in the Con Cuong District were heavily disturbed secondary vegetation in and around the Khe Bo commune, elevation 200-300m.
Methods and collecting protocols were designed to effectively sample both the general terrestrial invertebrate fauna and the focal taxa, provide an altitudinal distribution profile of the main study site (Huong Son Forest), and generate results for use in comparative analyses within and between surveys.
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: Ctenidae (Arachnida), Reduviidae (Heteroptera), Staphylinidae (Coleoptera), Vespidae and Braconidae (Hymenoptera), and Mycetophilidae and Drosophilidae (Diptera).
The collecting methods used at the main study site can be broadly categorized as either passive, permanently established traps, or active collection techniques used in appropriate microhabitats. Malaise traps, flight intercept traps, yellow pan traps and pitfall lines with drift fences (five 8" diameter buckets set at 3m intervals along a 20m transecting drift fence) were placed along the elevation transect near each of the four main work sites (220m, 650m, 920m, 1240m). Samples were collected weekly for the six weeks of the survey except for the flight intercept (2 weeks) and pitfall (5 weeks) traps. Additional malaise traps, flight intercept traps and pitfall lines without drift fences (sets of ten 3" diameter buckets) were located in microhabitats to increase trap productivity, sample diversity and focal taxa capture. These included a palm and cycad assemblage, light gaps, forest edges, and a disturbed streamside area. Active collecting techniques included litter sifter and aspirator, Winkler concentrator, sweep netting, aerial netting, beating and hand collecting. All of these methods were used in suitable habitats along the altitudinal transect to maximize the productivity and diversity of specific focal taxa samples (e.g., sweep netting in damp litter and near fruit falls and fungi to capture Drosophilidae and Mycetophilidae). Only active surveying methods were deployed at the two satellite sites.
Over 100,000 arthropods were collected during the 1998 surveys in Ha Tinh, Quang Binh and Nghe An Provinces. In order to process this enormous volume of material, the CBC established a dedicated invertebrate preparation laboratory at the AMNH. (For detailed information on the activities of the invertebrate preparation laboratory, please visit the CBC's Invertebrate Research Laboratory.) All specimens have been cleaned, sorted to order and family, and the wet collections labeled. Focal taxa specimens have been removed for analysis and focal groups in the orders Coleoptera, Diptera, Hymenoptera and Heteroptera have been prepared (sorted, mounted and labeled). To assist in the sorting and identification of the wet material, small synoptic collections of Coleoptera, Diptera and Hymenoptera were prepared from the 1998 specimens. Additionally, collections of Mymaridae (Hymenoptera), Trichoptera, Sciaridae (Diptera), Tettigoniidae (Orthoptera), and the families Cleridae, Ptylodactylidae, Throscidae, Leiodidae, Chrysomelidae, Elateridae, Carabidae, and the highly diverse Lampyridae in the order Coleoptera have been sent to outside specialists for analysis. The CBC is actively seeking collaborators to work with additional large and interesting groups from these surveys, including the families Ichneumonidae (Hymenoptera) and Cerambycidae (Coleoptera). The majority of these collections are currently housed in the Department of Invertebrate Zoology at the AMNH. Approximately 900 specimens of Braconidae have been prepared and repatriated to Dr. Long of IEBR for use in his continuing research on agriculturally important parasitoids. Additional specimens will be returned to Vietnam after identifications and descriptions are completed.
Results from the terrestrial invertebrate surveys are still very much preliminary and analyses continue. However, some descriptions and initial results organized by method and taxon are available.
New taxa descriptions resulting from the 1998 collections include (to date):
- A new genus, Loyugesa, in the Lygistorrhinidae (Diptera: Sciaroidea), a cosmopolitan family of 21 described species of fungus gnats found in tropical and warm temperate forests, based on the new species Loyugesa khuati (Grimaldi & Blagoderov, 2001). This species is named after Dr. Khuat Dang Long of IEBR, in recognition of his work and collegiality in the CBC-AMNH/IEBR biotic surveys.
- A new species of hover wasp, Cochlischnogaster spatulata, in the subfamily Stenogastrinae (Hymenoptera: Vespidae), a group endemic to the Oriental region (Carpenter, 2001; Carpenter & Starr, 2000).
- A new species of stingless bee, Lisotrigona carpenteri, in the tribe Meliponini (Hymenoptera: Apidae), an uncommon genus of the Indian and Southeast Asian meliponine fauna (Engel, 2000).
The vast majority (~75%) of invertebrates collected during the 1998 surveys were captured using malaise and flight intercept traps. At least 50 dominant families and an estimated minimum 100 families and 300-400 species total are present in these samples. Trapping results varied greatly over time, altitude, and between traps set at the same elevation, and a detailed analysis of altitudinal distribution patterns will have to wait until further identification work is completed. Notable findings include rare crepuscular staphylinid beetles in the subfamilies Staphylininae and Aleocharinae (Coleoptera: Staphylinidae) and seldom-collected specimens of small wasps.
Pitfall traps and drift fences collected a variety of millipedes, beetles and spiders. There was a high abundance and diversity of beetles in the families Carabidae and Scarabaeidae (Coleoptera), particularly the dung-rolling geotrupines. This result is interesting given the current low density of large mammals in Huong Son Forest. The small mammal fauna is abundant and diverse; it is possible that these taxa can survive primarily on their dung, although densities of the two groups were inversely correlated across elevation. (For results from the small and large mammal surveys of the Northern Truong Son Mountains, please visit the Mammalogy Biotic Surveys). Specific results from the spider collections are detailed below.
The litter sifter and aspirator and the Winkler concentrator methods were used primarily to collect beetles in the family Staphylinidae (Coleoptera) from forest floor litter. Collections were made primarily in the streamside microhabitats occupied by these beetles. The fauna was unexpectedly rich, and subfamilies collected included Paederinae, Staphylininae, Tachyporinae, Osoriinae, Oxytelinae, Steninae and Aleocharinae. All of these groups are known to contain large numbers of tropical taxa.
A modest diversity of drosophilids (estimated 30-35 species in 12 genera) was captured by sweep and aerial netting along the 220-1270m altitudinal transect at Huong Son. Sampling around fungi, fruit falls and inflorescence yielded a number of additional small fly taxa (Mycodrosophila, Hirtodrosophila, Zygothrica and Colocasiomyia). Preliminary results from netting samples of aculeate Hymenoptera suggest that the diversity of social wasps is quite high given the small number of specimens collected (<500). Solitary Vespidae and Eumeninae collections were also very productive; however, there were fewer active colonies of social wasps than expected. Beating and hand collecting techniques were used primarily for spider collections (see below).
Arachnida were extensively sampled during the survey using a variety of methods, including a protocol designed to collect and observe spiders in the family Ctenidae (wandering spiders). This family has been revised by Dr. Silva based in part on these collections (Silva, 2001). Results reveal a diverse spider community in the Northern Truong Son dominated by Indo-Malayan faunal elements. At least 38 families were collected, many of which were recorded for the first time in Vietnam. Abundance was highest in the families Zodariidae, Heteropodidae, Corinnidae, Salticidae and Lycosidae; species diversity was highest in the Salticidae, Theridiidae, and Araneidae. Notable findings include three taxa previously known only from Australia, Indonesia, and Java, respectively, and a species (Coelotes palinitropus Zu 1994) recorded only from an island in southern China. For a more detailed summary of the spider survey methods and results, including a preliminary list of families, please visit the 1998 Northern Truong Son Mountains Spider Survey.
Although the results detailed above are preliminary and tentative, they clearly suggest that the Northern Truong Son Mountains' eastern flanks house a diverse and biogeographically informative invertebrate fauna. Arthropods constitute a rich faunal group which can be systematically sampled, allowing comparative analyses both within and between survey locations. Results indicate a predominance of Indo-Malayan taxa, with both temperate and tropical components strongly represented. As analyses continue, it will be interesting to see if there is a significant altitudinal component structuring the distribution of species with these climatic affinities. Initial results from the malaise and flight intercept traps indicate an interesting if complicated relationship between elevation and diversity. The intrinsic species richness of the region's invertebrate fauna and the value of additional collections, independent of their conservation and biodiversity assessment utility, are also clear from these surveys. Early results from some focal taxa (Arachnida, Staphylinidae, social wasps) point to high diversity, and we expect new taxa descriptions to result from the continuing analyses.
The eastern slopes of the Northern Truong Son Mountains (Annamites) are a region with both high species diversity and a strong endemic component. These initial arthropod survey findings support conclusions from additional taxa surveys that Huong Son's forests have high biodiversity and conservation value representative of the region's lowland and premontane evergreen ecosystems.
Literature Cited - Arthropod Research
Carpenter, J.M. 2001. New generic synonymy in Stenogastrinae (Insecta: Hymenoptera; Vespidae). Natural History Bulletin of Ibaraki University, 5:27-30.
Carpenter, J.M., and C.K. Starr. 2000. A new genus of hover wasps from Southeast Asia (Hymenoptera: Vespidae; Stenogastrinae). American Museum Novitates, 3291:1-12.
Engel, M.S. 2000. A review of the Indo-Malayan Meliponine genus Lisotrigona, with two new species (Hymenoptera: Apidae). Oriental Insects, 34:229-237.
Grimaldi, D., and V. Blagoderov. 2001. A new genus of Lygistorrhinidae from Vietnam (Diptera: Sciaroidea), and phylogenetic relationships in the family. Studia Dipterologica, 8:43-57.
Silva, D. 2001. Species richness and phylogenetic diversity of Ctenid spiders (Araneae: Ctenidae). Unpublished doctoral dissertation, Cornell University.
For a detailed summary of sampling methods, results, and a preliminary list of families in the Arachnida collected during these surveys, please visit the 1998 Northern Truong Son Mountains Spider Survey.
Dr. Diana Silva, then a CBC-AMNH International Graduate Student Fellow, made intensive spider collections focusing on the family Ctenidae (wandering spiders) as part of the 1998 arthropod inventories in the Northern Truong Son Mountains. This family has been revised by Dr. Silva, based in part on these collections (Silva, 2001).
Spider inventories were made at two study areas in the Northern Truong Son Mountains. Extensive collections were made April 12-May 22, 1998, in the An River (Rao An) watershed in Huong Son Forest, Huong Son District, Ha Tinh Province (18° 22' N; 105° 13' E). Spiders were collected along an altitudinal range of 200-1150m, using pitfall traps and active collection techniques (e.g., beating). Small pitfall trap lines were set in conjunction with those for insects and small mammals at the following elevations and associated broad-leaved evergreen forest habitats: 1) 200m, seasonally inundated flood plain and riverine forest; 2) 600m, well-drained, closed-canopy forest on a ridgeline; and 3) 900m, moist, closed-canopy premontane forest. Additional sets of independent pitfall traps were established at 230m, 400m, 700m and 1150m in lowland through premontane forest habitats. Active collection techniques were employed at all elevations in light gaps and at edges in the primary forest interior, in specialized habitats (e.g., a Podocarpus-bamboo association above 1100m), in secondary forest, and in degraded habitats along streams and near agricultural disturbance.
A second set of spider collections were made April 25-May 3, 1998, at one of the satellite work sites located in Con Cuong District, Nghe An Province (19° 02' N, 104° 42' E). Collections were made using active collection techniques only at elevations of 300-500m. Sampling efforts focused on four main localities and habitats: 1) along Ngun stream in bamboo, highly degraded and old secondary forest; 2) along Khe Choang stream; 3) in recently logged, old secondary forest; and 4) in disturbed secondary habitats on the edge of limestone forest near Khe Bo commune.
The sampling protocol for spiders was designed primarily to observe and collect spiders in the family Ctenidae. These spiders are mainly nocturnal ambush predators and an effective inventory requires exhaustive sampling of a wide variety of microhabitats. These methods also collect specimens from many other spider communities and can provide a preliminary inventory of the general spider fauna present. Collection protocols used at the primary site (Rao An) were designed to comprehensively sample the Ctenidae and gather a large, general sample of the Huong Son fauna; at the secondary site (Con Cuong) the focus was on sampling microhabitats.
The spider pitfall traps used at Rao An consisted of twelve sets of ten 3" diameter and 6" deep plastic cups containing ethylene glycol set flush with the ground without a drift fence. Pitfall trap sets were placed in a variety of microhabitats in order to sample spider fauna diversity. Beating was used to sample communities on low tree branches and complex associations of dried leaves and twigs in shrubby understory vegetation. Sweep netting was used to collect small spiders hidden in low herbaceous vegetation. Sifting was used to collect spiders inhabiting forest floor litter. Spiders were hand-collected during day and night time surveys in microhabitats not otherwise sampled, including fallen logs, tree bark, crevices in rocks, streamside vegetation and partially submerged stones.
Specimens were also captured using protocols employed to collect other taxa. The general arthropod and mammalogy pitfall lines contributed spiders not captured by any other techniques, the mammalogists' pitfalls being particularly effective due to their larger size.
A majority of the spiders collected at Huong Son (Rao An) and Con Cuong were adult specimens; juveniles were avoided when possible because accurate identification of them can be problematic. All specimens were preserved in 70% alcohol in the field. Spiders from the 1998 survey have been cleaned, sorted to family (and genus or species where possible) and the wet collections labeled. These collections are currently housed in the Department of Invertebrate Zoology at the AMNH. A representative portion of the spider specimens will be repatriated to Vietnam after identifications and descriptions are completed.
Preliminary analyses indicate that at least 38 families are represented in these samples and that most are recorded for the first time in Vietnam. Abundance was highest in the families Zodariidae, Sparassidae, Corinnidae, Salticidae and Lycosidae; diversity was highest in the Salticidae (> 25 species), Theridiidae and Araneidae (> 10 species each). Analyses are ongoing and all identifications remain preliminary; any taxon numbers are tentative and represent approximations of true diversity. In general the spider community at Huong Son appears to be dominated by groups with Indo-Malayan affinities. At the generic level a large proportion of the taxa present are also common to other countries in Southeast Asia, including Thailand, Malaysia, Indonesia and Singapore. However, the richness of microhabitats and floral diversity in the An River watershed suggests that the geographic range of many of these species might be narrow. There was no evidence of differentiation across the 200-1000m altitudinal range. Further inventory work is necessary to confirm this result, and additional sampling in premontane and montane forest habitats at higher elevations (>1200m) may reveal differences across elevations not detected in this survey. Collections from degraded habitats sampled in Con Cuong District were surprisingly rich in species and there is a preliminary indication of family abundance and diversity variation between the two sites. However, we are unable to make quantitative or more detailed qualitative comparisons of diversity and abundance due to differences in survey time and methods.
There were qualitative differences between the spider fauna active during day and night at both sites. During the study period (March-April) the daytime spider community was dominated by hunters of the family Salticidae, occurring mainly on shrubs and herbaceous plants, and by members of the Lycosidae and the Linyphiidae, on the ground. Other frequently encountered daytime families include the Theridiidae and Areneidae. At night the dominant families recorded from hand collections and pitfalls were the Zodariidae and Corinnidae. Both are active hunters on the ground and around the bases of trees. The dominant group on vegetation at night was the hunter family Sparassidae.
Spiders were collected in pitfall traps set out specifically for arachnids as well as from pitfall lines with drift fences designed to capture small mammals and the general arthropod community. Standard pitfall lines collected numerous specimens in the families Lycosidae and Zodariidae as well as many other taxa from families such as the Salticidae, Oonopidae and Corinnidae. General entomology pitfall lines with drift fences collected the families Corinnidae, Zodariidae, Lycosidae and a small number of Ctenidae, among other taxa. Additional arachnid orders collected in pitfall traps included Schizomida (2 species), Opiliones (5 species), scorpions and pseudoscorpions.
A number of interesting taxa were collected only in the larger pitfall traps with drift fences used by the mammalogists. Several mygalomorph spiders were obtained from these, including two species of Atypidae, two probable species of Theraphosidae, one species of Ctenizidae, and several other taxa to be determined. These specimens include the first record of a male Cyclocosmia ricketti (Pocock), a species previously known only from female specimens collected in China and Thailand. Numerous specimens of araneomorph spiders were captured, including males, a single female and a juvenile ctenid also collected at night in forest along the Ngun stream (Con Cuong). Additional taxa collected by this method include: several specimens of Borboropactus, a taxon in the family Thomisidae known only from the Southeast Asian tropics; four species of Zodariidae; three species of Sparassidae; and species of Corinnidae belonging to the genera Castianeira, Oedignatha, and an unidentified genus which is apparently new and related to a group previously known only from Australia.
Hand collecting and sifting collected a number of notable taxa, some of them previously undescribed. Nighttime hand collecting produced three species of Ctenidae belonging to two genera. The genus Acantheisis represented by various males and females of species previously known only from Thailand. These individuals were collected from trees in a mixed bamboo and evergreen streamside habitat. The two additional species collected from the forest floor belong to a genus preciously known only from the Malayan region; one is recorded from Indonesia and the second is new to science.
Additional interesting taxa using these methods include a number of species from genera not previously recorded in Southeast Asia: Thelcticopis (Sparassidae), known only from East Asia and the Malay Archipelago prior to this survey; Anapogonia (Symphytognathidae), described only from Java; and the genusConculus(Anapidae) which is currently being revised and has been recorded only in Japan and Korea. The species Coelotes palinitropus (Zhu & Wang, 1994) in the family Amaurobiidae is only known previously from a small island in southern China. New taxon descriptions will likely include species in the genera Mallinella (Zodariidae), a widely distributed paleotropical group, and Panjange (Pholcidae), which has an Indo-Australian distribution.
Analyses of data gathered during the 1998 spider surveys on the east slope of the Northern Truong Son Mountains are still in their preliminary stages. However, a few broad conclusions can be drawn. First, specimens collected at the two sites include both previously undescribed taxa and a large number of new country records, indicating that Vietnam remains under-surveyed for the Order Aranaea. This conclusion likely applies to Cambodia and Lao PDR as well. Second, although the majority of taxa are from Indo-Malayan families with representatives found elsewhere in Southeast Asia, a number of genera with East Asian and particularly southern Chinese distributions were also present. The Truong Son Mountains are believed to represent a zone of overlap between the more northerly and temperate Sino-Himalayan biota found in northern Vietnam and southern China, and the more southerly Malesian fauna characteristic of tropical Southeast Asia. The presence of northern spider genera mixed in with the more typical fauna are consistent with this biogeographical explanation and suggest that arthropods may be good taxa with which to further refine these hypotheses. Third, the observed family-level community differences between Huong Son and Con Cuong need further investigation. Study area differences could be attributed to underlying community structure variation between the two sites, differences in the habitats sampled, or both. Resolution of the scale at which spider diversity is structured in the region will require further sampling in additional habitats and localities. Fourth, the lack of variation in the spider fauna with elevation at Huong Son is intriguing. Dominant tree families, vegetation structure, climate and rainfall all vary with altitude and it is surprising that differences between lowland and premontane broad-leaved evergreen forests were not detected. Additional sampling at higher elevations should be carried out before a firm conclusion can be drawn regarding elevation and spider fauna distribution. Finally, surveys of both birds and mammals in the Truong Son Mountains have detected distribution differences between the eastern (Vietnam) and western (Lao PDR) slopes with a suite of species restricted to the eastern slopes and lowlands. This has been attributed to a combination of climate and topography: on the eastern side the climate is relatively stable and wet most of the year, while drier southwesterly winds on the western side result in a more marked and severe dry season. It is likely that arthropod diversity and distribution patterns are affected by these factors as well and they provide a phylogenetically independent set of taxa with which to test this hypothesis. Results from the current survey suggest that spiders are an appropriate group for comparative analyses of arthropod abundance and diversity on the eastern and western slopes of the Northern Truong Son Mountains.
Literature Cited - Spider Report
Silva, D. 2001. Species richness and phylogenetic diversity of Ctenid spiders (Araneae: Ctenidae). Unpublished doctoral dissertation, Cornell University.
Zhu, C.-D., and J.-F. Wang. 1994. Seven new species of the genusCoelotesfrom China (Araneae: Agelenidae).Acta Zootaxonomica Sinica 19:37-45.
For a detailed summary of sampling methods and preliminary results from the general arthropod surveys, please visit the 1998 Northern Truong Son Mountains Arthropod Survey.
The 1998 herpetofauna survey team included Dr. David Kizirian from the American Museum of Natural History, New York, and Nguyen Quang Truong from the Institute of Ecology and Biological Resources, Hanoi.
Collections were made over a period of seven weeks in April and May, 1998, at three localities in the northern Truong Son Mountains.
The primary work site was located on the An River, Huong Son District, Ha Tinh Province (18° 22' N; 105° 13' E). At Rao An, specimens were collected April 19-22 and May 4-22, 1998, along an elevation range of 160-1200m. Sampled habitats included: seasonally inundated flood plain and riverine evergreen forest (220-230m), lowland broad-leaved evergreen forest (220-1000m), ridge forest (800-1000m), and premontane mixed broad-leaved evergreen and coniferous forest (above 1000m).
Additional collections were made at two satellite sites: Cha Lo, Minh Hoa District, Quang Binh Province (17° 42' N, 105° 45' E), and a number of localities in Con Cuong District, Nghe An Province (19° 02' N, 104° 42' E). Collection activity at the satellite sites was more limited and occurred at lower elevations (< 400m) than at Rao An. At Cha Lo, collections were made April 13-16, 1998, in closed lowland broad-leaved evergreen forest at elevations between 250 and 400m. Specimens were collected April 25-May 2, 1998, in the Con Cuong District at elevations between 200 and 300m. Habitats sampled at Con Cuong were mostly heavily disturbed secondary vegetation in and around the Khe Bo commune.
The primary sampling method was visual encounters during day and nighttime opportunistic collecting. The vast majority of specimens were obtained this way. Visual encounters included searches along streams, under rocks and logs, and within leaf litter. Turtle traps were established at Rao An at the lowland work site for approximately one month, and at Con Cuong for two nights. Additional specimens were collected opportunistically in both mammalogy and entomology pitfall trap lines.
Approximately 700 specimens were collected during the 1998 surveys, representing 37 species and 5 families of amphibians and 37 species and 10 families of reptiles. Specimens were fixed in formalin and preserved in alcohol, and 120 tissue samples were collected for DNA analysis. Half of the alcohol-preserved specimens have been repatriated to the IEBR in Hanoi; the other half are currently housed in the collections of the Department of Herpetology at the AMNH.
The herpetofauna observed at the primary work site in the Rao An watershed was large and diverse, with a rich community of amphibians and reptiles across the sampled elevations. Survey team members spent the longest period of time at this work site, and a wider range of habitats and altitudes was sampled compared to the other localities. A total of 71 species (35 amphibian, 36 reptile) were collected, a number of which had restricted elevation or habitat distributions. Unique to elevations below 600m at Huong Son were four species of snake (Bungarus multicinctus,Rhabdophis sp., and the restricted-rangeCalamaria buchiandSinonatrix aequifasciata) and two frog species (Ophryophryne sp.and the restricted-rangeRhacophorus calcaneus). The colubrid snake specimenC. buchirepresents a range extension for this species, a Vietnamese endemic previously known only from the Da Lat Plateau, Lam Dong Province. Unique to elevations above 900m were two species of snakes (Trimeresurus stejnegeriand the restricted-rangeElaphe mandarina), two turtle species (Manouria impressaandPlatysternon megacephalum), and two frog species (Huia nasicaandRhacophorusbipunctatus). Species found at sampling sites throughout the watershed includedAcanthosaura lepidogaster,Physignathus cocincinus,Limnonectes kuhliicomplex, and the human commensalsBufo melanostictusandPolypedatesleucomystaxcomplex. Notable range extensions for two restricted-range species were recorded at Huong Son:Amolops cremnobatus, a new country record for Vietnam (Bain & Truong, 2001a), andRana chapaensis, a new provincial record for Ha Tinh Province (Bain & Truong, 2001b). Additional collecting at some localities in this rich site would likely increase both the number of species identified from restricted microhabitats and the total number of species recorded.
A total of 16 species were collected in four nights of sampling at the first satellite study site, Cha Lo, from a small riparian system also sampled by ichthyologists and entomologists. The majority of species (14) were amphibians, including a morphologically and ecologically diverse assemblage of rhacophorid tree frogs (four species) and ranid frogs (seven species). The variety of these sympatric species and other herpetofauna indicate a relatively high level of diversity and ecosystem health along this watershed, despite increasing degradation of the surrounding forest.
Sampling at the second satellite site, a group of localities in the Con Cuong District, produced the least diverse fauna of any of the work sites. A total of 20 (10 amphibian, 10 reptile) species were found during the five nights of sampling at a variety of sites and elevations. However, the highly disturbed habitats around the villages at Khe Bo commune yielded the only specimens of one species of snake (Boiga kraepelini) and one genus of lizard (Takydromus spp.).
Noteworthy findings from the 1998 herpetofauna survey in the northern Truong Son Mountains include the diversity of amphibians and reptiles across elevations in the Rao An watershed and the sympatric rhacophorid and ranid species assemblages found during one night of sampling at Cha Lo. Approximately 19% (7/37) of amphibians and 2.7% (1/37) of reptiles collected were endemic or restricted-range species.
Although no provincial herpetofauna list exists for Ha Tinh Province, most species collected occupy expected or known ranges. Significant range extensions recorded during this survey include a new country record (Amolops cremnobatus), a new provincial record (Rana chapaensis), and a significant range extension for the Vietnamese endemic snake speciesCalamaria buchi, previously known only from the Central Highlands. Fifteen species remain unidentified, nine of which are believed to be previously undescribed. We are currently working on new species descriptions for these taxa. A lacertid specimen collected at Huong Son has been designated a paratype for the newly described grass lizardTakydromus hani(Chou, Nguyen & Pauwells, 2001) and is currently housed at the Institute for Ecology and Biological Resources, Hanoi.
In general the specimens collected throughout the survey indicate the biogeographic affinity of the northern Truong Son Mountains with Sino-Himalayan taxa found in northern Vietnam, southern China, northern Burma and across the Himalayan Mountain range. This is particularly true for the anurans, including the restricted-range speciesLeptobrachium chapaense,Ophryophryne spp., andRana johnsi. Additionally, taxa distributed throughout Southeast Asia and the Indo-Malay archipelago were identified, as well as a species of rhacophorid generally found in southern Vietnam (Rhacophorus calcaneus). These findings indicate an overlap between northern sub-tropical, southern tropical and broadly distributed fauna which contributes to the high herpetofauna diversity in this region.
A number of species of conservation interest were found at Rao An, including three turtle species listed as Vulnerable or Endangered by the IUCN (2000):Pyxidea mouhotii,Manouria impressaandPlatysternon megacephalum. However, the lack of a more diverse and abundant aquatic turtle and large snake fauna from the otherwise rich Rao An and Cha Lo work sites is of note. These animals are presumably subjected to high local hunting pressure, and their apparent absence from otherwise healthy and robust herpetofauna populations must be viewed with concern.
Literature Cited - Herpetology Research
Bain, R.H., and Nguyen Quang Truong. 2001a. Geographic distribution. Amolops cremnobatus. Herpetological Review, 32:269.
Bain, R.H., and Nguyen Quang Truong. 2001b. Geographic distribution. Rana chapaensis. Herpetological Review, 32: 272.
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 1998 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. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). 2001. "Appendices I, II and III." Retrieved June 27, 2001 from Convention on International Trade in Endangered Species of Wild Fauna and Flora: http://www.cites.org/.
3. Bourret, R. 1936. Les Serpents de l'Indochine, Vols. 1 & 2. Libraire pour les Sciences Naturelles, Paris.
4. Bourret, R. 1942. Les Batraciens de l'Indochine. Gouvernment général de l'Indochine, Hanoi.
5. Campden-Main, S.M. 1970. A Field Guide to the Snakes of South Vietnam. Smithsonian Institution, Washington, D.C.
6. Cox, M.J., P.P. van Dijk, J. Nabhitabhata, and K. Thirakupt. 1999. A Photographic Guide to Snakes and Other Reptiles of Peninsular Malaysia, Singapore and Thailand. Ralph Curtis Publishing, Sanibel Island, FL.
7. Darevsky, I.S. 1999. The herpetofauna of some offshore islands of Vietnam, as related to that of the adjacent mainland. In: Ota, H. (ed.), Tropical Island Herpetofauna: Origin, Current Diversity, and Conservation, pp. 27-42. Elsevier, Amsterdam.
8. Fei, L. (ed.). 1999. Atlas of Amphibians of China. Henan Publishing House of Science and Technology, Zhengzhou.
9. Frost, D.R. 1985. Amphibian Species of the World: A Taxonomic and Geographical Reference. Association of Systematic Collections and Allen Press, Lawrence, KA.
10. Frost, D.R. 2000. "Amphibian Species of the World: An Online Reference, v. 2.20" (http://research.amnh.org/herpetology/amphibia/index.html). American Museum of Natural History, New York, NY.
11. Inger, R.F. 1966. The systematics and zoogeography of the amphibia of Borneo. Fieldiana: Zoology, 52:188-191, 364.
12. Inger, R. F. 1999. Distribution of amphibians of southern Asia and adjacent islands. In: Duellman, W.E. (ed.), Patterns of Distribution of Amphibians: A Global Perspective, pp. 445-482. Johns Hopkins University Press, Baltimore, MD.
13. Inger, R.F., N. Orlov, and I. Darevsky. 1999. Frogs of Vietnam: a report on new collections.Fieldiana: Zoology, New Series, 92:iii-iv, 1-46.
14. Iverson, J.B. 1992. A Revised Checklist with Distribution Maps of the Turtles of the World. Private Printing, Richmond, IN.
15. Lathrop, A., R.W. Murphy, N. Orlov, and Ho Thu Chuc. 1998. Two new species of Leptolalax (Anura: Megophryidae) from northern Vietnam.Amphibia-Reptilia, 19:253-267.
16. Lathrop, A., R.W. Murphy, N. Orlov, and Ho Thu Chuc. 1998. Two new species of Leptobrachium (Anura: Megophryidae) from the Central Highlands of Vietnam with a redescription of Leptobrachium chapaense. Russian Journal of Herpetology, 5:51-60.
17. Liu, C.-C., and S.-Q. Hu (as S.-C. Hu). 1961. Chinese Tailless Amphibians. Science Press, Peking.
18. Manthey, U., and W. Grossman. 1997. Amphibien & Reptilien Südostasiens. Natur und Tier-Verlag, Berlin.
19. Nussbaum, R.A., Jr., E.D. Brodie, and Y. Datong. 1995. A taxonomic review of Tylototriton verrucosus Anderson (Amphibia: Caudata: Salmandridae). Herpetologica, 51:257-268.
20. Orlov, N.L., R.W. Murphy, and T.J. Papenfuss. 2000. List of snakes of Tam-Dao Mountain Ridge (Tonkin, Vietnam). Russian Journal of Herpetology, 7:69-80.
21. Orlov, N., A. Lathrop, R.W. Murphy, and Ho Thu Cuc. 2001. Frogs of the family Rhacophoridae (Anura: Amphibia) in the Northern Hoang Lien Mountains (Mount Fan Si Pan, Sa Pa District, Lao Cai Province), Vietnam.Russian Journal of Herpetology, 8:17-44.
22. Ota, H., M.W. Lau, T. Weidenhöfer, Y. Yasukawa, and A. Bogadek. 1995. Taxonomic review of the geckos allied to Gekko chinensis Gray 1842 (Gekkonidae Reptilia) from China and Vietnam.Tropical Zoology, 8:181-196.
23. Pope, C.H. 1935. Reptiles of China: Turtles, Crocodilians, Snakes, Lizards. American Museum of Natural History, New York, NY.
24. Smith, M.A. 1931. The Fauna of British India, Including Ceylon and Burma: Reptilia and Amphibia. Vol. 1: Loricata, Testudines. Taylor and Francis, London.
25. Smith, M.A. 1935. The Fauna of British India, Including Ceylon and Burma: Reptilia and Amphibia. Vol. 2: Sauria. Taylor and Francis, London.
26. Smith, M.A. 1945. The Fauna of British India, Including Ceylon and Burma: Reptilia and Amphibia. Vol. 3: Serpentes. Taylor and Francis, London.
27. Taylor, E.H. 1962. The amphibian fauna of Thailand.University of Kansas Science Bulletin, 43:265-599, errata.
28. Taylor, E.H. 1963. The lizards of Thailand.University of Kansas Science Bulletin, 44:687-1077.
29. Taylor, E.H. 1965. The serpents of Thailand and adjacent waters.University of Kansas Science Bulletin, 55:610-1096.
30. Welch, K.R.G. 1994. Snakes of the World: A Checklist. Vol. 1: Venomous Snakes. Longdunn Press, Bristol.
31. Welch, K.R.G. 1994. Snakes of the World: A Checklist. Vol. 2: Boas, Pythons, Shield-tails, and Worm Snakes. Longdunn Press, Bristol.
32. Yang, D. 1991. Phylogenetic systematics of the Amolops group of ranid frogs of Southeastern Asia and the Greater Sunda Islands.Fieldiana: Zoology, New Series, 63:1-42.
33. Yang, D.-T., S. Li, W. Liu, and S. Lu (eds.). 1991. Amphibian-Fauna of Yunnan. China Forestry Publishing House, Beijing.
34. Zhao, E.-M., and K. Adler (eds.). 1993. Herpetology of China. Society for the Study of Amphibians and Reptiles, St. Louis, MO.
The 1998 ichthyology survey team members were Radford Arinndell and Dr. Barbara Brown from the American Museum of Natural History, New York, and Le Hung Anh and Dr. Nguyen Kiem Son from the Institute of Ecology and Biological Resources, Hanoi.
Specimens were collected April 11-27, 1998 from four locations in the northern Truong Son Mountains of Vietnam along the international border with Lao PDR.
The primary work site was located in the watershed of the An River, Huong Son District, Ha Tinh Province (18° 22' N; 105° 13' E). Surveys were carried out along the granite-bottomed streams of the Rao An and its tributaries in the Huong Son Forest. The surrounding vegetation was relatively undisturbed lowland and premontane broad-leaved evergreen forest. These collections from the Rao An watershed were supplemented with local market purchases within the District.
Three additional satellite sites were sampled. At Cha Lo, Minh Hoa District, Quang Binh Province (17° 42' N, 105° 45' E), fishes were collected from both low and high gradient rocky streams situated in a closed lowland broad-leaved evergreen forest. At Khe Bu, Con Cuong District, Nghe An Province (19° 02' N, 104° 42' E), a low gradient stream was sampled in a heavily disturbed area: the forest had been burned to the stream edge and there was a significant amount of algae in the water. Finally, fishes were collected from a stream located in a well-populated area at Khe Ve, Minh Hoa District, Quang Binh Province (17° 55' N, 105° 49' E).
Field collections were supplemented by market specimens from three additional locations: Quy Dat Market, Minh Hoa District, and Ferry (Minh Cam) and Dinh Le Markets, Tuyen Hoa District, all in Quang Binh Province.
Collecting methods were limited to dip nets and gill nets. Habitats sampled and time constraints prevented the effective use of seine nets. Rotenone and electro-shocking were not employed.
More than 800 specimens representing 56 taxa in 17 families were collected during the 1998 ichthyology surveys in the northern Truong Son Mountains. Captured and purchased fishes were fixed in 10% formalin and subsequently preserved in 75% ethanol. Approximately two-thirds of the specimens are currently housed in the collections of the Department of Ichthyology at the AMNH; the remainder have been returned to Vietnam. Additional returns will be made after identifications and descriptions are completed.
This survey recorded a diverse and relatively undisturbed freshwater ichthyofauna from three provinces in the northern Truong Son Mountains. The collections included a significant number of new country records for Vietnam and potentially undescribed species. Additionally, the surveys recorded a relatively low number of introduced species, indicating that widespread distribution of exotics is not yet a problem in these areas.
The distribution of taxa was strongly skewed across both the localities and families collected. Over half of the taxa (32/56, or 57.1%) were collected from only one of the seven locations, and only one site (Quy Dat Market) had no unique specimens. At the family level, the Cyprinidae was by far the most abundant group, containing 50% (28/56) of all the taxa collected. Only two other families (Cobitidae and Gobiidae) contained as many as five taxa, and a majority (11/17, or 64.7%) were represented by a single taxon. Both of these results indicate that regional freshwater fish species diversity and distribution may be highly localized and spatially structured. However, they may also reflect under-sampling during this survey (see below).
Two factors prevent a more complete assessment of fish species diversity, distribution patterns and regional conservation value based on the survey results. First, the freshwater ichthyofauna of Vietnam specifically and Southeast Asia as a whole remains under-surveyed and consequently under-described (Lundberg, et al., 2000). The current survey reflects this: over one-third of the taxa collected (21/56, or 37.5%) are currently either unidentified or tentatively identified. Second, limitations on time and collection methods resulted in under-estimation of true species diversity, even at the most intensively collected site along the An River.
Noteworthy findings from the 1998 ichthyofauna survey in the northern Truong Son Mountains include diverse assemblages of hill and lowland fish species with an encouragingly limited number of exotics, new country records, and the potential presence of previously undescribed taxa. We are currently working on identifications and possible new species descriptions based on these specimens.
Overall, the freshwater fish fauna recorded from Nghe An, Ha Tinh, and Quang Binh Provinces in the northern Truong Son Mountains reflects the region's location at the overlap of northern Sino-Himalayan, southern Indo-Malaysian and Australasian biogeographic zones. Species diversity appears to be both relatively high and spatially structured, although interpretation of these patterns is complicated by problems of under-sampling and limited regional taxonomic knowledge. The primary locality along the An River in the Huong Son Forest is part of an intact, contiguously forested ecosystem with an extensive (albeit somewhat degraded) network of lowland river valleys, one of the most threatened habitats in Southeast Asia. Adding this unprotected watershed forest to the regional protected areas system would help conserve the rich and still poorly understood regional freshwater fish diversity.
Literature Cited - Ichthyology Research
Lundberg, J.G., M. Kottelat, G.R. Smith, M.L.J. Stiassny, and A.C Gill. 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.
For a preliminary list of species' identifications and localities collected from the 1998 freshwater fishes inventory in the northern Truong Son Mountains, please go to the 1998 Ichthyofauna Inventory.
Literature Cited - Fishes Recorded During the 1998 CBC-AMNH/IEBR Biotic Inventory Survey
1. FishBase (compiler). 2001. "FishBase: A Global Information System on Fishes." Retrieved October 3, 2001 from FishBase: http://www.fishbase.org/home.htm
2. Kottelat, M., pers. comm.
3. Ng, H.H., pers. comm.
Mammalogy Research (Small Mammal Survey)
The 1998 and 1999 mammalogy survey team included Eric Brothers, Darrin Lunde and Dr. Guy Musser from the American Museum of Natural History, New York, and Pham Duc Tien and Nguyen Xuan Tam from the Institute of Ecology and Biological Resources, Hanoi.
The mammal survey was conducted April 13 - May 22, 1998 and March 26 - April 25, 1999 at the An River, Huong Son District, Ha Tinh Province, located in the Northern Truong Son Mountains along the international border with Lao PDR (18° 22' N, 105° 13' 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.
The Huong Son Forest contains the headwaters of four rivers (Rao An, Nam Sot, Nam Mac and Song Con). The primary vegetation along the valley bottoms and slopes is broad-leaved evergreen forest. Sampling was carried out along an elevation range of 220-1270m and opportunistic observations of mammals and signs were made throughout the study area. Efforts focused on five main habitats along the transect: 1) seasonally inundated riparian flood plain evergreen forest (220-230m); 2) disturbed primary and secondary lowland evergreen forest (250m); 3) closed canopy primary lowland and premontane broad-leaved evergreen forest (250-1000m, sampling focused at 680m and 920m); 4) disturbed primary premontane mixed conifer and broad-leaved evergreen forest (1000-1150m), and 5) disturbed primary premontane mixed conifer and broad-leaved evergreen forest with a dense dwarf bamboo understory (1150-1270m).
Conventional traps, mist nets and pitfall lines were used to assess the diversity of the small mammal species present. Conventional traps (Conibear steel traps, Tomahawk live cage traps, Sherman aluminum live traps, Victor rat snap-traps, and Museum Special mouse snap-traps) were baited with a mixture of peanut butter, oatmeal, raisins and raw bacon and set in microhabitats where small mammals were likely to appear, such as liana tangles, hollow logs and runways. Mist nets were placed along waterways, in forest gaps, and adjacent to fruiting trees (elevation: 200-1000m), and were left open from dusk until 8pm and occasionally overnight. Fifty meter pitfall lines with drift fences were placed in forest habitats at 230m, 680m, 920m and 1240m. In addition to trapping, all opportunistic sightings and signs of mammals were recorded.
The 1998 and 1999 mammal survey team positively identified 40 species in 18 families and 8 orders at Huong Son. Over 550 specimens were collected during the two field seasons, representing 35 species in 15 families and 7 orders. Specimens were preserved as either whole alcoholic specimens or prepared as skins and skulls. Approximately one-third of the specimens have been repatriated to the IEBR in Hanoi; the remaining specimens are currently housed in the collections of the Department of Mammalogy at the AMNH.
The small mammal community observed in the Rao An watershed was diverse, intact and abundant. Species present were typical of those associated with primary evergreen forests in this geographic region and at the elevations sampled. An analysis of elevation data indicated that some distributions were correlated with altitude, with species found only in lowland forests (< 250m), species restricted to premontane forests (>1000m), and species common across the elevation transect. Different trapping methods and placement was important in accurately recording species composition and abundance. Pitfall lines, although relatively unproductive (c. 0.5 captures/day) were the only method by which three species were detected: Short-tailed GymnureHylomys suillus,Crocidura sp., and Sikkim MouseMus pahari. Arboreal trapping (e.g., vines, liana tangles) provided the majority of records of Lang Bian White-bellied RatNiviventer langbianis and the only specimens of Pencil-tailed Tree MouseChiropodomys gliroides.
The survey records include a number of rare, endemic and threatened mammals. Results from mist-netting efforts include a number of rare, threatened vespertilionid bat species (Lunde, Musser, & Pham, submitted). Spotted LinsangPrionodon pardicolor, is a nocturnal, largely arboreal viverrid rarely observed throughout its known range (Evans, et al., 2000). Annamite Striped RabbitNesolagus timminsi, a recently described lagomorph, is apparently restricted to the Truong Son Mountains along the Lao PDR-Vietnam border (Surridge, et al., 1989, Averianov, et al., 2000). Globally Threatened and Near Threatened species known to be present in Huong Son Forest include three bat species (M. annectans,P. paterculusandP. cadornae), Assamese MacaqueMacaca assamensis, Gibbon speciesHylobates sp., and East Asian PorcupineHystrix brachyura(after Hilton-Taylor, 2000).
The complete absence of human commensals (Rattus rattus,Mus musculus,Suncus murinus) and species associated with habitats modified by human activity (Bandicota spp.) indicates that the Huong Son Forest is currently a healthy and relatively undisturbed forested ecosystem with potentially high conservation value. The threeRattusspecies (Himalayan RatR. nitidus, Sikkim RatR.remotusand Tanezumi RatR. tanezumi) caught during the survey are generally associated with agriculture and other disturbed areas. However, these species were confined to rivers and streams running into and through the study area. Such waterways probably represent the natural habitat of these species, and may provide routes by whichRattus spp.can invade disturbed forest areas.
Noteworthy findings from the 1998 and 1999 mammal survey in the Huong Son Forest include the description of an abundant and healthy small mammal community with no human commensal species; records of bat, primate and rodent species of global conservation significance; and evidence for the recently described Annamite Striped RabbitNesolagus timminsi. Additionally, this survey has provided baseline data on taxonomy and species diversity which will enable continued monitoring of Huong Son Forest. We are currently preparing detailed descriptions of specimens, habitat and elevation associations and survey results from this work.
The mammal community observed at Huong Son is typical of the region's lowland and premontane evergreen forests, encompassing northern Sino-Himalayan, southern Indo-Malayan and regional endemic components. Despite limited evidence of large mammal presence, the forest ecosystem appears relatively healthy and robust, with little current impact on the small mammal community from human activity along the watershed. Although far from pristine, its health and location within a contiguously forested habitat block makes Huong Son Forest an important component in northern Truong Son Mountain conservation. The presence of Globally Threatened and Near Threatened species and of a probable regional endemic (N. timminsi) both re-enforce Huong Son's biodiversity and conservation value.
Literature Cited - Mammalogy Research (Small 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.
Evans, T.D., J.W. Duckworth, and R.J. Timmins. 2000. Field observations of larger mammals in Laos, 1994-1995. Mammalia, 64:55-100.
Hilton-Taylor, C. (compiler). 2000. "2000 IUCN Red List of Threatened Species." International Union of the Conservation of Nature (IUCN), Gland and Cambridge.
Lunde, D.P., G.G. Musser, and Pham Duc Tien. First record of Myotis annectans from Vietnam and additional specimens of rare bats (Chiroptera: Vespertilionidae). Submitted:Mammalia.
Lunde, D.P., and Nguyen Truong Son. 2001. "An Identification Guide to the Rodents of Vietnam." Center for Biodiversity and Conservation at the American Museum of Natural History, New York, NY.
Surridge, A.K., R.J. Timmins, G.M. Hewitt, and D.J. Bell. 1999. Striped rabbits in Southeast Asia. Nature, 400:726.
Literature Cited - Mammals Recorded During the 1998/99 CBC-AMNH/IEBR Biotic Inventory Survey (Small Mammal 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 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 results are included in the summary report (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. Four main lowland valleys were visited: Rao An, 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.
Data was gathered during opportunistic diurnal searching and observation; total survey effort was 29 person-days across all habitats. Observations were made while walking along trails and during occasional periods of static watching. An emphasis was placed on recording 'key species' considered important in national, regional and global contexts. Abundance and status were assessed based on encounter frequency, vocalizations, and factors such as ecology and behavior which affect species' observability.
A total of 141 species in 33 families were recorded and positively identified during the 1999 ornithological survey in the Huong Son Forest. Six of these are considered of global conservation significance: Crested ArgusRheinardia ocellata (Globally Threatened-Vulnerable) and Chestnut-necklaced PartridgeArborophila charltonii, Red-collared WoodpeckerPicus rabieri, Brown HornbillAnorrhinus tickelli, Blyth's KingfisherAlcedo hercules, and Short-tailed Scimitar BabblerJabouilleia danjoui (all Globally Near Threatened) (after Stattersfield, Capper & Dutson, 2000). Three species recorded have regionally restricted ranges:J. danjoui is distributed East of the Mekong in Vietnam and Lao PDR, and Red-vented BarbetMegalaima lagrandieriand Grey-faced Tit BabblerMacronus kelleyi are distributed in this region and Cambodia (after Robson, 2000).
The bird communities recorded at Huong Son were generally characteristic of the habitat types and altitudes surveyed and of the biogeographic location of the forest. The degraded areas along valleys bottoms were characterized by a suite of widespread species. Interestingly, Short-tailed ParrotbillParadoxornis davidianus, an uncommon species with a poorly understood distribution, was found in this habitat. Characteristic lowland valley species included Rufous-throated FulvettaAlcippe rufogularis,A. hercules(Globally Near Threatened) andM. kelleyi(regional endemic). The bird community observed at the highest altitudes was transitionally between mid-altitude and montane to sub-montane altitude avifauna. Mountain BulbulHypsipetes mcclellandii, Puff-throated BulbulAlophoixus pallidus, and Mrs. Gould's SunbirdAethopyga gouldia(a characteristic montane species) were found only on a high ridge at 1200-1250m.
These results are consistent with known regional bird distribution patterns and reinforce previously recorded faunal differences between the eastern and western slopes of the Truong Son Mountain Range. Three species which were relatively common at Huong Son, Fork-tailed SunbirdAethopyga christinae,J. danjoui, andR. ocellata, are either scarce or have restricted distributions to the west in Lao PDR. Conversely, Moustached BarbetMegalaima incognita, which is the commonest mid-altitude barbet in Nakai-Nam Theun NBCA, was not recorded during this survey. At a larger scale, the bird community from these forests reflect the overlap of northern Sino-Himalayan and southern Indo-Malayan biota which is characteristic of central Vietnam's biogeography.
Despite its limited length and scope, there were few absences in the bird records which could not be explained by the timing of the survey. Field work coincided with the end of the spring passage and the nesting and fledging periods of many species, both of which reduced the likelihood of seeing or hearing birds. There was evidence that the abundance of some large bird species may have been reduced by hunting. Large quarry species characteristic of these habitats, including large hornbillsBuceros/Aceros,A.tickelli,R. ocellata, Hill MynaGracula religiosaand imperial pigeonDucula, were either absent or present at reduced densities. It is clear that the Huong Son Forest avifauna remains under-inventoried, and further survey efforts are necessary to better understand species diversity, distribution and status in these habitats.
Noteworthy findings from the 1999 ornithology survey at Huong Son include descriptions of bird communities characteristic of habitat, elevation and the Northern Truong Son region, and records of three regionally endemic and six Globally Threatened or Near Threatened species. Given the length of time in the field, the recorded bird communities are remarkably complete when compared to expected species diversity.
The Huong Son Forest is located in the northern section of the Truong Son Mountains, a range of low-lying hills and mountains running roughly north to south along the Vietnam-Lao PDR border and into southern central Vietnam. The Truong Son avifauna (and other biota) are notable for their high species richness and endemic taxa, and for distribution differences between the drier, more seasonal western slopes and wetter, more climatically stable eastern ones. Results from the current survey reflect and support these conclusions.
It is this combination of rich biodiversity and endemism and its location in an intact, contiguously forested ecosystem which makes Huong Son a region of high conservation significance. Additionally, Huong Son contains an extensive (albeit somewhat degraded) network of forested lowland river valleys, one of the most threatened habitats in Southeast Asia. The survey's ornithological records indicate both the value of the forest to conservation (presence of regional endemics and threatened species) and current threats (hunting and habitat degradation). 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 - 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.
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.
A corresponding list and survey report has been published in the following report and is available as a downloadable PDF:
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 Study for Large Mammals and Birds." Center for Biodiversity and Conservation at the American Museum of Natural History, New York.
For a list of species identifications and conservation status from the 1999 ornithology survey at Huong Son Forest, Ha Tinh Province, please go to the 1999 Northern Truong Son Ornithology Inventory.
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.