Cat Tien National Park Research Articles

Orchid epiphytes do not receive organic substances from living trees through fungi.

Numerous studies of terrestrial orchids have demonstrated widespread partial mycoheterotrophy, particularly the possibility of obtaining organic matter from surrounding trees through a common fungal network. Fungi are also widespread in epiphytic orchid roots, but there have been no attempts to determine if epiphytes accept organic matter from the living stems of their phorophytes. We hypothesise that such transfer does not exist because epiphytes and phorophytes harbour different fungal communities. To test this hypothesis, we tagged three short Randia sp. trees with 13C-enriched CO2 and examined 13C transfer from the phorophyte into the epiphytic orchids Grosourdya appendiculata, Dendrobium oligophyllum and Gastrochilus sp. in Cat Tien National Park, (South Vietnam, Cat Tien National Park, plot size approx. 1ha). The coincidence of fungal sequences in the orchid roots and in the branches on which they grew was also examined. We did not detect 13C label moving from phorophytes to epiphytes. Using Illumina sequencing, 162 fungal operational taxonomic units (OTUs) were detected. The fungal communities were significantly different between the roots of epiphytes and branches of phorophytes, although no strict fungal specificity at the species level was found in either epiphytes or phorophytes.

<p><strong><em>Cryptomonas cattiensis</em></strong><strong> <em>sp. nov.</em> (Cryptophyceae: Cryptomonadales), a new species described from Vietnam</strong></p>

A new species, Cryptomonas cattiensis sp. nov., is described from Vietnam based on morphological and molecular data. Phylogenetic relationships inferred from nuclear small and large subunit ribosomal DNA, internal transcribed spacer 2, and plastid psbA sequences show that the new species forms a separate branch on the phylogenetic tree of the genus Cryptomonas. This species has slightly sigmoid to elliptical cells in ventral view and a single plastid, deeply notched into several irregular lobes, with two pyrenoids. C. cattiensis has been observed in one locality in Cat Tien National Park.

Chitinophaga tropicalis sp. nov., isolated from forest soil.

A novel bacterial strain, designated ysch24T, was isolated from a forest soil sample collected from the Cat Tien National Park, southern Vietnam. Cells were Gram-stain-negative, aerobic, gliding, filamentous or rod-shaped. The results of 16S rRNA gene analyses revealed that strain ysch24T belongs to the genus Chitinophaga, and was most closely related to Chitinophaga silvisoli GDMCC 1.1411T (97.4 %), followed by Chitinophaga oryziterrae JCM 16595T (97.3 %) and Chitinophaga sancti NBRC 15057T (96.9 %). The average nucleotide identity and digital DNA-DNA hybridization values between strain ysch24T and closely related type strains were 72.0-74.0 % and 19.1-19.4 %, respectively. Major fatty acids were iso-C15 : 0, C16 : 1 ω5c and iso-C17 : 0 3-OH and the predominant respiratory quinone was menaquinone 7. Polar lipids consisted of phosphatidylethanolamine, four unidentified aminophospholipids, two unidentified phospholipids and four unidentified lipids. The genomic DNA G+C content was 45.6 mol%. The study clearly showed that strain ysch24T should represent a novel species of the genus Chitinophaga, for which the name Chitinophaga tropicalis sp. nov. is proposed. The type strain is ysch24T (=GDMCC 1.1355T=KACC 21527T).

Monitoring of Forest Land Use/Cover Change in Cat Tien National Park, Dong Nai Province, Vietnam Using Remote Sensing and GIS techniques

The Cat Tien National Park in the south of Vietnam represents a protected ecological area. It is located in tropical rainforest zone. For monitoring purposes of forest land use/cover change of the park satellite images (Landsat 5, Landsat 7 and Sentinel-2A) taken in 1988, 2003 and 2019 were used. NDVI was used for the estimation of vegetation quality. Forest land use/cover were classified by 5 categories using maximum likelihood classifier algorithm in ENVI 5.3. After classification, differentiation of forest land use/cover was analyzed on every image. Deforestation took place in 1988-2003 periods and broad-leaved forest areas have undergone reduction. Currently, new policies were introduced to reduce deforestation and therefore support free growth of tropical forest areas.

Molecular and morphological characterisation of flatworm larvae parasitising on fish in Cat Tien National Park, Vietnam

Molecular and morphological characterisation of flatworm larvae parasitising on fish in Cat Tien National Park, Vietnam

New records of <i> Hipposideros griffini </i> from lava caves and the threats to its conservation in Vietnam

Lava caves are unique and fragile ecosystems which are suitable for a wide variety of plant and animal species. However, the biodiversity of lava caves is still poorly studied. To increase knowledge of these special ecosystems, several rapid surveys on bats were carried out in Dak Nong Province in sounthern Vietnam between 2014 and 2019. Bats were captured in the field using mist nets and harp traps. Echolocation calls were recorded in different situations using the PCTape system. The results include records of Griffin’s leaf-nosed bat (Hipposideros griffini) which is regarded as a species endemic to Vietnam only. Prior to the present study, it was only recorded from karst and moutain habitats in three different regions of Vietnam: Cat Ba National Park in the northeast, Chu Mom Ray in the central highlands, and Cat Tien National Park in the southeast. Records of Hipposideros griffini from Dak Nong Province extend its distributional range and highlight the importance of lava cave systems for biodiversity research and conservation in Vietnam. Griffin’s leaf-nosed bat and other animal species inhabiting the lava caves have been critically threatened by hunting and other human activities. Morphological measurements and echolocation calls of Hipposideros griffini together with the threats to its conservation status in Dak Nong Province are given in this paper.

New records of <i> Hipposideros griffini </i> from lava caves and the threats to its conservation in Vietnam

Lava caves are unique and fragile ecosystems which are suitable for a wide variety of plant and animal species. However, the biodiversity of lava caves is still poorly studied. To increase knowledge of these special ecosystems, several rapid surveys on bats were carried out in Dak Nong Province in sounthern Vietnam between 2014 and 2019. Bats were captured in the field using mist nets and harp traps. Echolocation calls were recorded in different situations using the PCTape system. The results include records of Griffin’s leaf-nosed bat (Hipposideros griffini) which is regarded as a species endemic to Vietnam only. Prior to the present study, it was only recorded from karst and moutain habitats in three different regions of Vietnam: Cat Ba National Park in the northeast, Chu Mom Ray in the central highlands, and Cat Tien National Park in the southeast. Records of Hipposideros griffini from Dak Nong Province extend its distributional range and highlight the importance of lava cave systems for biodiversity research and conservation in Vietnam. Griffin’s leaf-nosed bat and other animal species inhabiting the lava caves have been critically threatened by hunting and other human activities. Morphological measurements and echolocation calls of Hipposideros griffini together with the threats to its conservation status in Dak Nong Province are given in this paper.

Cladoceran diversity in Vinh Long province and redescription of the rare species <i> Grimaldina brazzai </i> richard, 1892 (Macrotricidae, Anomopoda, Branchiopoda) for zooplankton fauna Vietnam

In a total of four surveys at eight sites in some major rivers in Vinh Long province during 2013 to 2014, 18 species of cladoceran, belonging to 14 genera, 7 families and 2 orders, were recorded. The cladocerans fauna in Vinh Long province is recognized as moderate diverse, and the species recorded were mostly common species. Among 18 species, Grimaldina brazzai Richard, 1892 is a rare species. A total of four females specimens of species G. brazzai were collected at the Co Chien river, but male specimens were absent. The specimens were morphologically identified as G. brazzai described first by Richard (1892), followed by Brook (1959), Idris (1983), Smirnov (1992) and Hollwedel (2003). Grimaldina brazzai is currently the only one species in the genus Grimaldina and has been recorded in several tropical countries, such as Brazil, Thailand, Laos, Philippines, Indonesia, Malaysia, Cambodia and Singapore. They occur in lakes and rice fields, but population of this species is very limited in nature. In Vietnam, this species was first recorded in South Vietnam by Shirota (1966), but has not been described since then until recently Sinev & Korovchinsky (2013) recorded this species in the Cat Tien National Park, Dong Nai province, South Vietnam.

Cladoceran diversity in Vinh Long province and redescription of the rare species <i> Grimaldina brazzai </i> richard, 1892 (macrotricidae, anomopoda, branchiopoda) for zooplankton fauna Vietnam

In a total of four surveys at eight sites in some major rivers in Vinh Long province during 2013 to 2014, 18 species of cladoceran, belonging to 14 genera, 7 families and 2 orders, were recorded. The cladocerans fauna in Vinh Long province is recognized as moderate diverse, and the species recorded were mostly common species. Among 18 species, Grimaldina brazzai Richard, 1892 is a rare species. A total of four females specimens of species G. brazzai were collected at the Co Chien river, but male specimens were absent. The specimens were morphologically identified as G. brazzai described first by Richard (1892), followed by Brook (1959), Idris (1983), Smirnov (1992) and Hollwedel (2003). Grimaldina brazzai is currently the only one species in the genus Grimaldina and has been recorded in several tropical countries, such as Brazil, Thailand, Laos, Philippines, Indonesia, Malaysia, Cambodia and Singapore. They occur in lakes and rice fields, but population of this species is very limited in nature. In Vietnam, this species was first recorded in South Vietnam by Shirota (1966), but has not been described since then until recently Sinev & Korovchinsky (2013) recorded this species in the Cat Tien National Park, Dong Nai province, South Vietnam.

An Application of Autonomous Recorders for Gibbon Monitoring

Population monitoring is very important in wildlife management and conservation. All 18 species of gibbons are considered threatened with extinction and listed on the IUCN Red List of Threatened Species. Thus, understanding and effectively monitoring their population trends and distribution are critical. Thus far, all gibbon surveying and monitoring programs have been conducted by human surveyors; this is expensive, laborious, and dependent on the surveyors’ skills. In particular, estimating group density often requires a large sample size with several skilled observers working simultaneously in the field. We used autonomous recorders to record the calls of southern yellow-cheeked crested gibbon (Nomascus gabbrielae) for at least 3 days at each of 57 posts in Nam Cat Tien sector, Cat Tien National Park, Vietnam from July to October, 2016. We extracted gibbon calls from the recordings auditorily or visually using spectrograms in RAVEN software. We detected gibbon calls at 40 recording posts during the survey. The proportion of recorders with gibbon calls in the eastern region of Nam Cat Tien sector (mean = 0.79; SE = 0.13) was higher than that in the western region (mean = 0.46; SE = 0.11). The estimated probability of occurrence in the eastern region (ψ = 0.56; SE = 0.20) was higher than that in the western region (ψ = 0.23; SE = 0.16). Passive acoustic data were useful to investigate spatial variation in the probability of occurrence of gibbon. We recommend using autonomous recorders combined with occupancy model to complement human surveyors in gibbon monitoring in areas with low gibbon density because it is efficient, low cost, and not subject to errors caused by human surveyors. In the areas of high gibbon density, absolute density estimate achieved by human surveyors might be a more suitable indicator.

Tri thức bản địa về sử dụng thực vật rừng ăn được của đồng bào S’tiêng ở Vườn quốc gia Cát Tiên

Based on surveys combining household interviews with Participatory Rural Appraisal (PRA) and the “walk-in-the-wood” method, this paper is to examine the knowledge of S’tieng ethnic minorities in harvesting and using edible forest plants in Cat Tien National Park. The survey identified 94 species of edible forest plants belonging to 44 families used. The majority of them were herbs (37.2%), followed by trees (23.4%), shrubs (20.2%), and finally climbers (19.2%). Plants used as vegetables accounted for 59.6% of the total and 12.8% had UI ≥ 0.8. Many species used as vegetables have been important materials for the favourite daily food of S’tieng ethnic minorities and become an important part of their traditional food culture. However, the knowledge of S’tieng ethnic minorities has not been paid attention to applying, preserving and developing through sustainable plant use yet. So the indigenous knowledge should be applied to sustainable edible plant use and conservation. Especially, the harmful harvesting practices need bannning soon. The highly valued forest plants traditionally used by S’tieng ethnic should be domesticated and commercialized.

Myriapoda communities in a reforestation area and mature forest in Cat Tien national park

The Myriapoda community of 20-year old replanted forest surrounded by native lowland monsoon tropical forest in Cat Tien National Park, Southern Vietnam, was investigated in comparison with native forest and the same plantations 6 years ago. The author found that the Myriapoda community in replanted forest is very different from the mature forest community in species composition, structure, and abundance, and it has typical features of a soil community in a young, non-stable system. However after comparing the community in replanted forest with the same community 6 years later the author found a progressive dynamic in developing soil community into one similar to a mature forest community.

A distance sampling approach to estimate density and abundance of gibbon groups.

All 18 species of gibbons are considered threatened with extinction and listed on the IUCN Red List of Threatened Species. Because gibbons (Hylobatidae) are one of the most threatened primate families, a great need exists to determine and monitor their status effectively. To meet this need, we employed distance sampling methods to estimate the density and number of gibbon groups. We focused on southern yellow-cheeked crested gibbon in the Nam Cat Tien sector of Cat Tien National Park, Vietnam, from July to October, 2016. We used an auditory point count method at 48 listening posts to detect gibbon groups. We estimated our detection probability of calling groups of gibbons within 1,200 m of a listening post was 0.63 (95% CI: 0.54-0.74). In addition, we estimated the daily calling probability of a gibbon group to be 0.46 (95% CI: 0.33-0.59) and interpreted this as the probability that a group was available to be detected. We adjusted our group density and abundance estimates by both detection and availability probabilities. Ultimately we estimated 325 (95% CI: 232-455) gibbon groups in the Nam Cat Tien sector. Our results suggest that Cat Tien National Park contains one of the largest populations of southern yellow-cheeked crested gibbon in Vietnam. Our methods are one way of avoiding underestimation of gibbon group density and abundance by incorporating uncertainty in gibbon group availability and detection.

Falsiplecta integripedia gen. et sp. nov. from Vietnam (Gastropoda, Pulmonata, Helicarionidae)

On the territory of Cat-Tien National Park a new species of land snails has been found. Anatomical study has shown that the new species belongs to a new genus probably distantly related to the genus Hemiplecta . Illustrated description is presented.

A new species of Eustigmaeus (Acari: Prostigmata: Stigmaeidae) from Vietnam

A new species of the genus Eustigmaeus (Acari: Stigmaeidae), E. vietnamiensis sp. nov. is described from the bark of fig tree ( Ficus sp.) in Cat Tien National Park, Vietnam. The mite family Stigmaeidae is recorded from Vietnam for the first time.

Exploitation the cultural values of the Ma ethnic community in the buffer zone of Cat Tien national park to develop tourism: A case study in Ta Lai Commune

Established in 1998, Cat Tien National Park – the 41th Biosphere reserves of the world is not only highlighted with abundant fauna and flora but also a living locality of many native tribes with featured cultural tradition, in which most of population is the Ma people, mainly rounding up at Ta Lai village of the buffer zone of Cat Tien National Park. The variation about cultural tradition, customs and festival has made cultural humanity resources of this area more plentiful. However, the effectiveness of the exploitation of original culture of Ma people to develop tourism is still not true with its inherent advantages. This paper aims to show the potential, current state of development, im- pacts and solutions to exploit the cultural values of the Ma community in Ta Lai in order to develop tourism on the perspective of sustainable development standpoint.

Improving the Estimation of Calling Probability and Correction Factors in Gibbon Monitoring Using the Auditory Point Count Method

Estimating the population size of primate species is very important in identifying appropriate conservation actions and measuring their effectiveness. All 17 species of gibbons recognized by the IUCN are considered threatened with extinction. Thus, there is a great need to determine and monitor their status, to conduct effective conservation interventions. Gibbons can be detected by their loud and long song bouts, and surveys usually rely on auditory point count methods. However, gibbon groups do not call daily, so we need a correction factor based on the daily calling probability to estimate gibbon population size accurately. Several studies have estimated such correction factors, but these estimates might be negatively biased if gibbon groups move beyond the maximum hearing distance or are far from the listening post and their calls are faint. We aimed to address this issue and estimate the calling probability and correction factor accurately. We collected data on southern yellow-cheeked crested gibbon (Nomascus gabriellae) in Cat Tien National Park, Vietnam, from July to October 2016, using an auditory point count method. We explored the influence of the maximum distance between the listening post and the gibbons on estimates of the calling probability, correction factor, and population size. We detected 44 gibbon groups during the survey. The calling probability and correction factor decreased with the maximum distance from the listening post to the gibbon groups. If we used all the gibbon groups to estimate the correction factor, population estimates were 15% and 18% higher than those estimated using only gibbon groups detected within 700 m and 500 m, respectively. Based on these findings, we recommend that researchers calculate the calling probability and correction factor for several maximum distances and determine the percentage overestimation of the gibbon population. They should then choose the correction factor so as to balance sample size and the risk of overestimation of gibbon population size.

Key to the lichen families Pyrenulaceae and Trypetheliaceae in Vietnam, with eight new records

An identification key is presented for the members of the lichen families Pyrenulaceae and Trypetheliaceae in Vietnam. Eight pyrenocarpous species (in Anthracothecium, Astrothelium, Lithothelium, and Pyrenula) collected from Nam Cat Tien National Park, are new records for Vietnam. Taxonomic characters of the species are given along with ecology, distribution, and illustrations.

A new species of Sobarocephala Czerny, 1903 (Diptera: Clusiidae) from Vietnam

Sobarocephala is the most diverse genus of druid flies Clusiidae, known from all biogeographic regions. Two species, S. apoxys and S. triangula were known from Vietnam. Sobarocephala cattiensis sp.nov. from Vietnam is described and illustrated. The new species is close to S. megastylis and to S. cycla. This new species was collected in Cat Tien National park (Dong Nai Province), in a seasonal tropical forest.http://www.zoobank.org/urn:lsid:zoobank.org:pub:58CFBCD7-B876-4B09-9E17-5E70D0B586D7

NEW FINDINGS NOTES OF THE PARASITIC NEMATODES OF TERRESTRIAL INVERTEBRATES IN VIET NAM

First results of the parasitological survey of Vietnamese terrestrial invertebrates performed in 2007 demonstrate extreme diversity of nematodes parasitic in these animals. The most interesting new findings are nematodes of four superfamilies: Drilonematoidea, Thelastomatoidea, Rhabditoidea and Ransomnematoidea. Further progress was achieved in last three years in the studies of Drilonematoidea nematodes – coelomic parasites of earthworms. One new genus and several new species were discovered in large megascolecids collected in Bac Bo (Tam Dao) and Nam Bo (Bidoup - Nui Ba N.P.). Passalidae beetles are colonial coleopterans inhabiting rotten wood in tropical forests throughout tropics, and are known as characteristic hosts of one taxon of parasitic nematodes – family Hystrignathidae. The nematodes of this family were reported for the first time from Viet Nam in 2007. The fauna of parasitic nematodes of terrestrial mollusks is also diverse in Viet Nam. In addition to the new angiostomatids described in 2005 new Angiostoma species with unusual morphology was discovered in Cat Tien National Park. Nematodes of the family Hethidae were discovered in Vietnamese diplopods in 1997 but not identified up to species level. Examination of Heth specimens under light microscope and scanning electron microscope demonstrate prominent morphological differences between three samples from different areas in Viet Nam. Additional studies are needed to reveal the relationships of parasitic nematodes of terrestrial invertebrates found in Vietnam in 2007 and publish valid descriptions of these new taxa.