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Research Article
Lithocarpus vuquangensis (Fagaceae), a new species from Vu Quang National Park, Vietnam
expand article infoNgoc Nguyen Van§, Hung Nguyen Viet|, Binh Hoang Thi§, Shuichiro Tagane, Hironori Toyama, Hoang Thanh Son, Ha Tran Viet#, Tetsukazu Yahara
‡ Kyushu University, Fukuoka, Japan
§ Dalat University, Dalat, Vietnam
| Vu Quang National Park, Ha Tinh, Vietnam
¶ Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Ha Noi, Vietnam
# Vietnam National University of Forestry, Ha Noi, Vietnam
Open Access

Abstract

Lithocarpus vuquangensis Ngoc & Hung is described from Vu Quang National Park, North Central Vietnam. The morphological comparison and phylogenetic analysis based on rbcL, matK and ITS provided evidence that the new species was not assignable to any of the previously known taxa in Vietnam and its surrounding countries. The description, photographs, preliminary conservation status and DNA barcode sequences are also provided for the new species.

Keywords

Fagaceae, Lithocarpus, new species, phylogeny, taxonomy, Vietnam, Vu Quang National Park

Introduction

It has been known that species richness of the genus Lithocarpus Blume (Fagaceae Dumorier) is high in Vietnam where 120 species and two varieties have been reported including the recently published species, L. dahuoaiensis Ngoc & L. V. Dung (Ban 2003, Ho 2003, Ngoc et al. 2016). Here, an additional new species of Lithocarpus is described from Vu Quang National Park located in Ha Tinh Province, North Central Vietnam (Figure 1).

Figure 1. 

Location of Vu Quang National Park (Black triangle), type locality of Lithocarpus vuquangensis.

Vu Quang National Park covers an area of ca. 56,000 ha from lowlands (alt. 10–300 m) to the highlands (the highest peak of Rao Co, alt. 2,286 m). Two new species of mammals (Sao La - Pseudoryx nghetinhensis, Artiodactyla and the world’s largest muntjac - Muntiacus vuquangensis, Cetartiodactyla) were discovered from this national park in the 1990s (Dung et al. 1993, 1994). The vegetation is diverse along the elevation gradient and five major forest types are recognised: lowland forests (alt. 10–300 m), hill forest (alt. 300–1,000 m), medium montane forest (alt. 1,000–1,400 m), montane forest (alt. 1,400–1,900 m) and upper montane forest (alt. 1,900–2,100 m) (Kuznetsov 2001, Vu Quang National Park Management Board 2014). Until now, 1,678 species of vascular plants including many endemic and rare species have been reported (Vu Quang National Park Management Board 2014, Tagane et al. 2016). As for Fagaceae, one species of Castanea Mill, nine species of Castanopsis (D. Don) Spach., 12 species of Quercus L. and 37 species of Lithocarpus Blume have been recorded from the National Park, amongst which 10 species have been listed in Viet Nam Red Data Book (Ban et al. 2007, Hung et al. 2014). In addition, natural populations of Trigonobalanus verticillata Forman were discovered during the authors’ recent botanical surveys in the National Park in 2016 (voucher specimens: Yahara et al. V5764 & V5766, DLU, FU, the herbarium of Vu Quang National Park), which brings the number of Fagaceae genera in the region up to five.

From 2015 to 2016, floristic expeditions were carried out in Vu Quang National Park and trees of the genus Lithocarpus were discovered that did not match any described species. Here, the authors describe and name it as Lithocarpus vuquangensis Ngoc & Hung, sp. nov. accompanied with its photographs and the morphological comparison with related species. In addition to the morphological examination, DNA sequences and phylogenetic analysis are extremely helpful for identifying and delimiting species (Hebert and Gregory 2005, Dick and Webb 2012). Here, parts of the DNA barcode regions rbcL, matK (CBOL Plant Working Group 2009) and ITS (China Plant BOL Working Group 2011) were sequenced and the phylogenic relationship of L. vuquangensis and its related taxa were examined.

Materials and methods

Morphological observations

The morphological traits of the new species were compared with its putative relatives based on systematic literature (Camus 1948, Huang et al. 1999, Ban 2003, Ho 2003, Phengklai 2008) and more than three hundreds dried specimens kept in the following herbaria were also examined: BKF, DLU, FOF, HN, KYO, P, RUPP, TI and VNM as well as digitised plant specimen images available on the web of JSTOR Global Plants (https://plants.jstor.org/), Muséum National d’Histoire Naturelle (https://science.mnhn.fr/) and Chinese Virtual Herbarium (http://www.cvh.org.cn/).

DNA extraction and sequencing

Total DNA was extracted from 17 silica-gel dried leaf pieces collected in the field. DNA extraction was performed using the CTAB method (Doyle and Doyle 1987) with minor modifications described in Toyama et al. (2015). Two chloroplast DNA barcode regions, rbcL and matK, were amplified and sequenced following published protocols (Kress et al. 2009, Dunning and Savolainen 2010). In addition, the internal transcribed spacer (ITS) region was sequenced using the protocol of Rohwer et al. (2009) with a minor modification in PCR amplification using the Tks GflexTM DNA Polymerase (Takara Bio Inc., Japan).

Phylogenetic analysis

A total of 16 accessions representing 15 species of Lithocarpus, collected throughout Vietnam, were analysed (Table 1). In addition, Trigonobalanus verticillata Forman was used as an outgroup in the phylogenetic analysis. The sequence alignment was performed by ClustalW with default parameters implemented in MEGA v 7.0.25 (Kumar et al. 2016) and subsequently adjusted manually.

List of taxa used in this study with vouchers and GenBank accession number.

Species Vouchers GenBank accession number
rbcL matK ITS
Lithocarpus aggregatus Tagane et al. V6288 (DLU, FU) LC318967 LC318550 MF770309
Lithocarpus bidoupensis Tagane et al. V4320 (DLU, FU, VNM) LC318961 LC318547 KY940070
Lithocarpus coalitus Tagane et al. V4191 (DLU, FU, VNM) LC318959 LC318545 MF770305
Lithocarpus dahuoaiensis Ngoc et al. V3194 (DLU, FU, HN, K, KYO, P, VNM) LC318953 LC318551 KY436002
Ngoc et al. V5404 (DLU, FU) LC318964 LC318548 MF770307
Lithocarpus gigantophyllus Ngoc et al. V3185 (DLU, FU) LC318951 LC318538 MF770299
Lithocarpus hancei Ngoc et al. V5111 (DLU, FU) LC318963 LC318970 MF952868
Lithocarpus hongiaoensis Ngoc et al. V3235 (DLU, FU) LC318956 LC318542 KY851759
Lithocarpus lemeeanus Tagane et al. V4273 (DLU, FU) LC318960 LC318546 MF770306
Lithocarpus licentii Ngoc et al. V3205 (DLU, FU) LC318954 LC318540 MF770301
Lithocarpus longipedicellatus Nguyen et al. V3813 (DLU, FU) LC318958 LC318544 MF770304
Lithocarpus ombrophilus Yahara et al. V3000 (DLU, FU) LC318949 LC318420 MF770297
Lithocarpus pseudomagneinii Ngoc et al. V3223 (DLU, FU) LC318955 LC318541 MF770302
Lithocarpus stenopus Ngoc et al. V3187 (DLU, FU) LC318952 LC318539 MF770300
Lithocarpus vinhensis Nguyen et al. V3787 (DLU, FU) LC318957 LC318543 MF770303
Lithocarpus vuquangensis Yahara et al. V5743 (DLU, FU) LC319671 LC319670 KY786083
Trigonobalanus verticillata Yahara et al. V5764 (DLU, FU) LC318965 LC318549 MF770308

Bayesian Inference (BI) of phylogeny was performed on the concatenated data set of three genes (rbcL, matK and ITS) using MrBayes v. 3.2 (Huelsenbeck and Ronquist 2001, Ronquist et al. 2012). The hierarchical likelihood ratio test (hLRT) and Akaike Information Criterion (AIC) were used to select the best model of evolution using MrModeltest v. 2.3 (Nylander 2004). The nucleotide substitution model was set to GTR+γ as selected by MrModeltest. Four independent Markov Chain Monte Carlo (MCMC) runs of four chains each were run for 10,000,000 generations sampling every 1,000 generations. The programme Tracer v. 1.6 (Rambaut et al. 2014) was used to examine marginal prior and posterior densities of MCMC outputs. Each run produced 10,001 trees and a relative burnin of 25% was used for diagnostics. Consequently, 7,501 trees of each run were sampled to generate the summary tree and posterior probabilities distributions. The summary tree was visualised and edited with FigTree v1.4.3 (http://tree.bio.ed.ac.uk/software/figtree/).

Results

The morphological comparison showed that Lithocarpus vuquangensis is most similar to L. nantoensis (Hayata) Hayata distributed in Taiwan, in having entire leaf margin, mostly solitary, rarely 2 or 3 clustered cupules, cupules not completely enclosing nut and glabrous nut. The Vietnamese species sharing the above diagnostic feature of L. vuquangensis are L. hongiaoensis, in ined. (Ngoc et al. in review) and L. vinhensis A. Camus. However, the new species is clearly different from all three in the following points: L. vuquangensis is distinguished from L. nantoensis by its fewer secondary veins (7–10 pairs vs. 10–15 pairs), shorter infructescences (4–7 cm long vs. 16 cm long), longer fruiting stalks (4–6 mm long vs. almost sessile), larger nut size (1.7–2.0 cm high by 2.1–2.4 cm in diam. vs. 1.4–1.7 cm high by 1.5–1.6 cm in diam.) and larger basal scar of the nut (ca. 1.1 cm in diam. vs. 0.5–0.8 cm in diam.). Lithocarpus vuquangensis is distinct from L. hongiaoensis by its shorter petioles (1–1.5 cm long vs. 2.1–3 cm long), shorter infructescences (4–7 cm long vs. 10 cm long), longer fruiting stalks (4–6 mm long vs. almost sessile), arrangement of scales on the cupule (scales arranged into concentric rings vs. imbricate, not forming rings) and larger nut size (1.7–2.0 cm long, 2.1–2.4 cm in diam. vs. 0.6–0.8 cm long, 1.2–1.5 cm in diam.). The new species differs from L. vinhensis in having fewer secondary veins (7–10 pairs vs. 11–12 pairs), shorter infructescences (4–7 cm long vs. 10 cm long) and larger nut size (1.7–2.0 cm long, 2.1–2.4 cm in diam. vs. 0.9–1 cm long, 1 cm in diam.). A more detailed comparison amongst these four species is shown in Table 2.

Morphological comparison of Lithocarpus vuquangensis with three related species: The measurements of L. nantoensis is derived from Hayata (1911), Liao (1996), Huang et al. (1999) and from digitised type specimen image (Kawakami & Mori 1157, TI); The measurements of L. vinhensis and L. hongiaoensis are derived from Camus (1948) and Ngoc et al. (in review), respectively.

Characters L. vuquangensis L. nantoensis L. hongiaoensis L. vinhensis
Leaf margin Entire Entire Entire Entire
Leaf surface Glabrous adaxially, adaxially white farinose Abaxially glaucous to light green and with adherent, waxy scalelike trichomes Glabrous upper, adherent waxy scale abaxially Glabrous adaxially, covered with very short white villi abaxially
Leaf blade size 7.5–11 × 2.3–3.6 cm 12–16 × 2.5–3.5 cm 9.6–14.5 × 2.5–3.8 cm 7.5 cm × 3 cm
Petiole length 1–1.5 cm long 0.7–1.3 cm long 2.1–3 cm long 1 cm long
Number of secondary veins 7–10 pairs 10–15 pairs 8–11 pairs 11–12 pairs
Infructescences length 4–7 cm long 16 cm long 12.5–16.5 cm long 10 cm long
Fruiting stalk length 4–6 mm long, 4–7 mm in diam. Almost sessile Sessile to 2 mm long 5–6 mm long
Cupule Solitary, 0.6–0.9 cm high by 1.8–2.2 cm in diam. Solitary, 1.2–1.5 cm in diam. Solitary, 1–1.2 cm high by 1.8–2.1 cm in diam. Solitary, 1.2–1.3 cm high by 0.8–1 cm in diam.
Scale arrangement Arranged into concentric rings Arranged into concentric rings Imbricate Arranged into concentric rings
Nut size 1.7–2.0 cm high by 2.1–2.4 cm in diam. 1.4–1.7 cm high by 1.5–1.6 cm in diam. 0.6–0.8 cm high by 1.2–1.5 cm in diam. 0.9–1 cm high by 1 cm in diam.
Nut enclosure by cupule Only basal to 1/4 of the nut Only basal part of the nut Enclosing ca. 1/3–1/2 of the nut Enclosing ca. 1/3–1/2 of the nut
Basal scar of the nut Concave, ca. 1.1 cm in diam. Concave, 0.5–0.8 cm in diam. Slightly concave, 1.2–1.4 cm in diam. Nearly flat

In the molecular phylogenetic tree (Fig. 2), L. vuquangensis is sister to L. hongiaoensis with the posterior probability of 0.94. One nucleotide substitution in rbcL, six in matK and six in ITS were found between these two species. On the other hand, L. vinhensis, another Vietnamese species most similar to L. vuquangensis, is placed in a separated clade which includes L. longipedicellatus, L. ombrophilus, L. gigantophyllus, L. licentii, L. pseudomagneinii and L. lemeeanus, with a posterior probability 0.93.

Figure 2. 

Bayesian phylogeny estimate of 15 taxa of Lithocarpus and one Trigonobalanus verticillata (as an outgroup) based on combined rbcL, matK and ITS sequences. Branches are labelled with posterior probabilities greater than 0.7.

Both Lithocarpus vuquangensis and L. vinhensis were collected in Vu Quang National Park, but these two species occur at different altitudes: L. vuquangensis was found between 1,500 m and 1,700 m altitude, while L. vinhensis was found at a lower elevation, below 1,100 m.

Discussion

Phylogenetically, L. vuquangensis is sister to L. hongiaoensis in ined. collected from Lam Dong Province located in southern Vietnam. These two species are morphologically distinguished in their length of infructescences and fruiting stalk, the arrangement of cupule bracts, nut size and other characteristics as summarised in Table 2. Further molecular phylogenetic studies, using additional DNA markers, are needed to clarify the relationship between L. vuquangensis and L. hongiaoensis. However, morphological differences are sufficiently distinct to distinguish them as different species.

Lithocarpus vuquangensis is also morphologically similar to L. vinhensis in having an entire leaf margin, solitary cupules not completely enclosing nut, scales arranged into concentric rings and glabrous nut, but these two species are not closely located in the phylogeny. This morphological similarity may have evolved in the similar habitat of the montane evergreen forest in Vu Quang National Park. Whereas L. vuquangensis and L. vinhensis were collected at 1,518 m and 1,062 m, respectively, altitudinal distributions of the two species may overlap in the montane evergreen forest.

The morphological comparison provided evidence to distinguish L. vuquangensis from a Taiwanese species, L. nantoensis, although the relationship between them remains to be clarified by further molecular phylogenetic studies.

Taxonomy

Lithocarpus vuquangensis Ngoc & Hung, sp. nov.

Figure 3

Diagnosis

Similar to Lithocarpus nantoensis, L. hongiaoensis and L. vinhensis, but distinguished from L. nantoensis mainly by its fewer secondary veins, shorter infructescences, longer fruiting stalk, larger nut size and larger scar size of the nut, from L. hongiaoensis by its much shorter petioles and infructescences, longer fruiting stalk, scales united into concentric rings and much larger nut size and from L. vinhensis by having fewer secondary veins, shorter infructescences and much larger nut size (Table 2).

Type

VIETNAM. Ha Tinh Province, Vu Quang National Park, in lower montane forest, along trail to the summit of Mt. Rào Cô, alt. 1518 m, 18°12'12.2"N, 105°23'15.3"E, 22 June 2016, Yahara T., Nguyen Van Ngoc, Toyama H., Tagane S., Okabe N., Nguyen Viet Hung V5743 (holotype: KYO!; isotypes: DLU!, FU!, HN!, K!, P!, VNM!).

Description

Trees, to 20 m tall; young branches mostly glabrous, yellowish in vivo, reddish-brown in sicco. Leaves alternate, spirally arranged, blade narrowly elliptic to lanceolate, 7.5–11 × 2.3–3.6 cm, crunchy, glabrous adaxially, white farinose abaxially, apex long acuminate, acumen up to 1.2 cm long, base cuneate to attenuate, margin entire and wavy; midrib flat or slightly prominent near base adaxially, prominent abaxially, greenish-yellow in vivo, reddish-brown in sicco, secondary veins 7–10 pairs, at an angle of 40–50 degrees from the midrib, prominent abaxially, tertiary veins scalariform, faintly visible to invisible on both sides; petiole 1–1.5 cm long, glabrous, terete. Male inflorescence a spike, 7–8.5 cm long. Male flower solitary; calyx 6-lobed, lobes ovate, 0.5–0.6 mm × 0.4–0.5 mm, pubescent on both surfaces; stamens 12, 0.7–0.9 mm long, anthers 0.1–0.15 mm long. Infructescences erect, woody spike, up to 7 cm long, axis ca. 2 mm thick at base, greyish-brown, lenticellate. Cupule solitary, broadly obconical to saucer-shaped, 1.4 cm long, 1.8 cm in diam., enclosing only basal to 1/4 of the nuts; scales triangular, arranged into 4–5 concentric rings, apex shortly acuminate, densely covered with tawny minute hairs; fruiting stalk ca. 4–6 mm long, 4–7 mm in diam. Nut obovoid or globose, 1.7–2.0 cm long, 2.1–2.4 cm in diam., glabrous, dehiscent; basal scar concave, ca. 1.1 cm in diam.

Figure 3. 

Lithocarpus vuquangensis Ngoc & Hung: A Branch with male inflorescences B Lower leaf surface C Holotype (KYO) D Spike with cupule E Young acorn F–H Side view, top view and scar of the mature nut, respectively I A part of infructescence K, L Inside and outside of the cupule. C, D, F–L From Yahara et al. V5743. Scale bars: 2 cm (D), 1 cm (F–H, K, L).

Phenology

Mature fruits were collected in June.

Distribution

Vietnam (so far known only from Vu Quang National Park, Ha Tinh Province) (Figure 1).

Etymology

The specific epithet is derived from its type locality, Vu Quang National Park.

GenBank accession No

Yahara et al. V5743: LC319671 (rbcL), LC319670 (matK), KY786083 (ITS).

Preliminary conservation status

Critically Endangered (CR). In the field observation, less than 10 individuals were found along the trail to the summit of Mt. Rào Cô, in lower montane forest. The habitat is inside the protected areas of Vu Quang National Park, but based on criterion D of the IUCN Red List criteria (IUCN 2012), this species is qualified as CR. Further intensive inventories are needed to find additional populations in Vu Quang National Park and its surrounding areas.

Acknowledgements

The authors thank the Director of Vu Quang National Park for providing us with opportunities to undertake field surveys in the protected area. We thank the curators and staff of the following herbaria BKF, DLU, FOF, HN, KYO, P, RUPP, TI and VNM for making their materials accessible. The present study was supported by the Environment Research and Technology Development Fund (S9 & 4–1601) of the Ministry of the Environment, Japan and MEXT/JSPS KAKENHI (Grant Number JP15H02640 and JP16H02553).

References

  • Ban NT (2003) Fagaceae. In: Ban NT (Ed.) Checklist of plant species of Vietnam 2. Agricultural Publishing House, Hanoi, 227–271.
  • Ban NT, Ly DT, Tap N, Dung VV, Thin NN, Tien VN, Khoi KN (2007) Vietnam Red Data Book Part II. Plants. Natural Sciences and Technology Publishers, Hanoi, 563 pp.
  • Camus A (1948) Les Chênes: Monographie du genres Quercus et Lithocarpus. Chênes Atlas Volume 3. Paul Lechevalier & fils, 1–1314.
  • CBOL Plant Working Group (2009) A DNA barcode for land plants. Proceedings of the National Academy of Sciences of the United States of America 106: 12794–12797. https:// doi.org/10.1073/pnas.0905845106
  • China Plant BOL Working Group (2011) Comparative analysis of a large dataset indicates that internal transcribed spacer (ITS) should be incorporated into the core barcode for seed plants. Proceedings of the National Academy of Sciences 108(49): 19641–19646. https://doi.org/10.1073/pnas.1104551108
  • Dick CW, Webb CO (2012) Plant DNA barcodes, taxonomic management, and species discovery in tropical forests. In: Kress WJ, Erickson DL (Eds) DNA barcodes: methods and protocols. Methods in Molecular Biology, vol. 858, 379–393. https://doi.org/10.1007/978-1-61779-591-6_18
  • Doyle JJ, Doyle JL (1987) A rapid DNA isolation procedure for small quantities of fresh leaf tissue. Phytochemical Bulletin 19: 11–15.
  • Dung VV, Giao PM, Chinh NN, Tuoc D, Arctander P, Mackinnon J (1993) A new species of living bovid from Vietnam. Nature 363: 443–445. https://doi.org/10.1038/363443a0
  • Hayata B (1911) Materials for a Flora of Formosa. The journal of the College of Science, Imperial University of Tokyo, Japan 30 (Art. 1): 1–471.
  • Ho PH (2003) An Illustrated Flora of Vietnam Vol. 2. Young Publishing House, Ho Chi Minh City, 951 pp.
  • Huang CJ, Zhang YT, Bartholomew B (1999) Fagaceae. In: Zhengyi W, Raven PH, Deyuan H (Eds) Flora of China. Volume 4, 333–369. http://www.efloras.org
  • Hung NV, Son NT, Toan TC, Phien DD, Son MT, Anh PNQ, Anh TD (2014) Results on species composition of Fagaceae at the Vu Quang National Park, Ha Tinh province. Vietnam Forest Sciences Journal 1: 3095–3100.
  • IUCN (2012) IUCN Red List Categories and Criteria. Version 3.1. Second edition. IUCN Species Survival Commission, IUCN, Gland, Switzerland and Cambridge, UK.
  • Kress WJ, Erickson DL, Jones FA, Swenson NG, Perez R, Sanjur O, Bermingham E (2009) Plant DNA barcodes and a community phylogeny of a tropical forest dynamics plot in Panama. Proceedings of the National Academy of Sciences of the United States of America 106(44): 18621–18626. https://doi.org/10.1073/pnas.0909820106
  • Kumar S, Stecher G, Tamura K (2016) MEGA7: Molecular Evolutionary Genetics Analysis Version 7.0 for Bigger Datasets. Molecular Biology and Evolution 33(7): 1870–1874. https://doi.org/10.1093/molbev/msw054
  • Kuznetsov A (2001) The forests of Vu Quang Nature Reserve: a description of habitats and plant communities. WWF, Hanoi, 1–102.
  • Liao JC (1996) Fagaceae. In: Huang TC (Eds) Flora of Taiwan. Volume 2, 51–123.
  • Ngoc NV, Dung LV, Tagane S, Binh HT, Son HT, Trung VQ, Yahara T (2016) Lithocarpus dahuoaiensis (Fagaceae), a new species from Lam Dong Province, Vietnam. PhytoKeys 69: 23–30. https://doi.org/10.3897/phytokeys.69.9821
  • Ngoc NV, Binh HT, Tagane S, Toyama H, Dang VS, Naiki A, Nagamasu H, Yahara T (in review) Two new species of Lithocarpus (Fagaceae) from Bidoup-Nui Ba National Park, Vietnam.
  • Nylander JAA (2004) MrModeltest 2.3. Program distributed by the author. Evolutionary Biology Centre, Uppsala University.
  • Phengklai C (2008) Fagaceae. In: Santisuk T, Larsen K (Eds) Flora of Thailand 9(3). The Forest Herbarium, Bangkok, 179–410.
  • Rohwer JG, Li J, Rudolph B, Schmidt SA, van der Wer H, Li HW (2009) Is Persea (Lauraceae) monophyletic? Evidence from nuclear ribosomal ITS sequences. Taxon 58(4): 1153–1167.
  • Ronquist F, Teslenko M, Van Der Mark P, Ayres DL, Darling A, Höhna S, Larget B, Liu L, Suchard MA, Huelsenbeck JP (2012) MrBayes 3.2: efficient Bayesian phylogenetic inference and model choice across a large model space. Systematic biology 61(3): 539–542. https://doi.org/10.1093/sysbio/sys029
  • Tagane S, Nguyen VH, Ngoc NV, Son HT, Toyama H, Yang C-J, Yahara T (2016) Homalium glandulosum (Salicaceae), a new species from Vu Quang National Park, North Central Vietnam. PhytoKeys 58: 97–104. https://doi.org/10.3897/phytokeys.58.6816
  • Toyama H, Kajisa T, Tagane S, Mase K, Chhang P, Samreth V, Ma V, Sokh H, Ichihasi R, Onoda Y, Mizoue N, Yahara T (2015) Effects of logging and recruitment on community phylogenetic structure in 32 permanent forest plots of Kampong Thom, Cambodia. Philosophical Transactions of the Royal Society B: Biological Sciences 370(1662): 20140008. https://doi.org/10.1098/rstb.2014.0008
  • Vu Quang National Park Management Board (2014) Planning for conservation and development of Vu Quang National Park 2015–2020. [In Vietnamese; published by author]