THE WORLD HERITAGE PHONG NHA - KẺ BÀNG NATIONAL PARK, QUẢNG B̀NH PROVINCE, VIỆT NAM

In the 2003 year a heartening event came to Vietnamese people in general, and Quảng B́nh people in particular - the Phong Nha - Kẻ Bàng National Park was recognized as "World Heritage" by UNESCO. On this occasion an author group from University of Natural Sciences, Hà Nội University and Centre of Forestry Resources and Environment, Institute for Forest Investigation and Planning under the editorship of Prof. Dr. Trần Nghi have been collaborating with one another to compile this book for contributing in the popularization of the miraculous abudance of the Vietnamese nature in a retired area, still unknown by many people.

The content of the work is as follows.

1. BRIEF NATURAL CONDITIONS

a. Climate. The climate in Phong Nha - Kẻ Bàng characterized by a tropical monsoon regime. There are two distinct seasons: hot dry and rainy. All climatic characteristics of the Phong Nha - Kẻ Bàng area is shown in Table 1.

Table 1. Some major climatic characteristics at Đồng Hới and Tuyên Hoá Stations

 

Đồng Hới Station

Tuyên Hoá Station

Temperature (oC)

Rainfall

(mm)

Humidity

(%)

Temperature

(oC)

Rainfall

(mm)

Humidity

(%)

Jan.

19.0

62.4

88

17.5

50.7

90

Feb.

19.3

43.4

85

18.8

34.9

90

Mar.

21.7

43.2

90

21.4

49.2

90

Apr.

24.9

56.1

87

24.8

65.0

86

May

28.0

106.0

79

27.7

140.7

80

Jun.

29.7

84.2

73

28.8

170.0

76

Jul.

29.7

86.9

72

29.2

136.1

72

Aug.

29.1

140.4

76

28.1

209.5

79

Sep.

27.0

444.6

85

26.2

530.1

88

Oct.

24.8

396.5

87

23.8

582.0

90

Nov.

22.4

366.2

88

20.9

231.4

90

Dec.

19.9

128.9

87

18.4

67.9

89

Annual

24.3

2159.4

83

23.8

2266.5

85

 

b. Hydrology. The Phong Nha - Kẻ Bàng is a catchment area of many streams and rivers which feed the Gianh River. There are some rivers in Phong Nha - Kẻ Bàng area, such as Chày, Troóc, Sơn. The flooding season takes place from Sept. to Nov., and dry season is from Feb. to Jul..

c. Soil. There are eight kinds of soil in the Phong Nha - Kẻ Bàng area. They are: 1) dark margalite-ferralite soil formed from limestone; 2) red and red-brown ferralite soil formed from limestone: 3) red-yellow ferralite soil formed from shale; 4) yellow-red ferralite soil formed from acidic magmatic rock; 5) yellow ferralite soil formed from sandstone; 6) alluvial soil situated in the valley and at the foot of limestone blocks; 7) alluvial soil situated along streams and rivers, and 8) yellow humic ferralite soil formed on low mountains.

d. Vegetation. There are about 96.2% of forest coverage in Phong Nha - Kẻ Bàng and 92.2% of which is primary forest. So, Phong Nha - Kẻ Bàng area has one of the highest percentage of forest coverage of the protected areas in Việt Nam.

e. Flora. Preliminary surveys of the botanical diversity of Phong Nha - Kẻ Bàng area are less than comprehensive. However, the results have been indicating a rich and diversed flora in this area with a preliminary list of vascular plant with 152 families, 511 genera and 876 species.

f. Fauna. Preliminary faunal surveys have identified 568 vertebrate species of 132 families, 44 orders, comprising 113 mammal species, 81 reptile and amphibian species, 302 bird species and 72 fish species

 

2. GEODIVERSITY

2.1. Stratigraphy

In the Phong Nha - Kẻ Bàng area there are from Paleozoi to Quaternary geological formations as follows.

 

PALEOZOIC ERATHEM

Upper Ordovician - Lower Silurian

Long Đại Formation (O3-S1 lđ): gneiss biotite - feldspar -sillimanite, schist, quartzite, sandstone, etc, about 900 m thick containing Graptolites.

 

Devonian

Hoa Sơn Group (D1-D2e hs) divided into two formations:

Rào Chan Formation (D1 rc): characterized by schist with interbeds or lenses of limestone, containing the fossils Dohmophyllum sp., Calceola sp., Desquamatia vijaica, Lissocrinus curtus, about 1500m thick.

Bản Giàng Formation (D1-D2e bg): grey sandstone, quartzite intercalated with limestone and schist containing abundant fossils: Calceola sandalina, Hexacrinites aff. biconcavus, Atrypa auriculata, etc, about 1000 m thick.

Mục Băi Formation (D2g mb): characterized by limestone intercalated with black clayey limestone containing abundant fossils: Stringocephalus burtini, Caliapora battersbyi, Scoliopora denticulata, etc.

Động Thờ Formation (D2g-D3fr đt): sandstone intercalated with siltstone and shale containing black organic matter and abundant fauna and flora fossils: Megachonetes sp., Schizophoria cf. ivanovi, Adolfia sp., Styliolina sp., Homoctenus sp., Protolepidodendron sp., Bergeria (Lepidodendropsis) sp..

Cát Đằng Formation (D3 cđ): mainly of limestome intercalated with some interbeds of shale containing the fossils Stachyodes aff. costulata, S. lagowiensis, Palmatolepis rhenana, etc, about 250 m thick.

 

Upper Devonian - Lower Carboniferous

Phong Nha Formation (D3-C1 pn): divided into three parts: lower part- massive grey limestone, about 100 m thick; middle part- limestone, about 140 m thick; upper part- shale, about 30 m thick. These beds yield a lot of fossils.

 

Lower Carboniferous

La Khê Formation (C1 lk): shale, siltstone, sandstone, etc, about 200 m thickness, containing a lot of fossils, such as Platycrinus sp., Pentagonocyclicus circumvallatus, Anthinocrinus ex gr. carbonicus; Globivalvulina sp., Glomodiscus sp., etc.

 

Carboniferous - Permian

Bắc Sơn Formation (C-P bs): massive limestone, from 600 to 1000 m thick, containing abundant fossils: Parathurammina suleimanovi, Archaesphaera minima, Eostaffella mosquensis, Mediocris mediocris,...

 

Upper Permian

Khe Giữa Formation (P3 kg): limestone, cherty limestone, black chert, about 100 m thickness, containing the foraminiferas: Neoschwagerina, Paraschwagerina, Codonofusiella nana, Neoendothyra eostaffeloidea, Lasiodiscus aff. tenuis, Nipponitella sp..

 

MESOZOIC ERATHEM

Cretaceous

Mụ Giạ Formation (K mg): including conglomerate, sandstone in the lower part and siltstone, shale, containing bivalve fossils such as Plicatounio sp., Trigonioides sp., Peregrinoconcha sp. (cf. P. chuxiongensis), Unio sp. and sporomorphs: Periplecotriletes sp., Leptolepidites sp.,.

 

CENOZOIC ERATHEM

Neogene

Đồng Hới Formation (N13-N21 đh). The Đồng Hới Formation is found in boreholes with three parts. The lower part includes pebble and gravels, sometimes intercalated with silty clay, from 30 to 160 m thick, containing the sporomorphs: Polypodium sp., Platicarya sp., Cystopteris sp., Ginkgo sp., Alnus sp.; the middle part comprises clay, sand, kaolin intercalated with pebbles, from 50 to 120 m in thickness; containing the sporomorphs: Polypodium sp., Cyathea sp., Lygodium sp., Selaginella sp.; the upper part includes clay, silt and gravel, from 50 to 100 m in thickness, containing the sporomorphs: Cycas sp., Taxodium sp., Quercus sp..

 

Quaternary

Middle-Upper Pleistocene. Lệ Ninh Formation (QI2-3 ln): found in boreholes with pebble, gravels grit and yellow to white-grey clay, without fossils.

Upper Pleistocene (QI3): mottley-coloured sand, silty sand and clay. They form the II step terrace with the elevation of 10-15 m surrounding the plain.

Lower-Middle Holocene (Q21-2). The Lower-Middle Holocene sediments are very different according to their origins. They were formed in marine, deltaic or territorial environment.

Upper Holocene (Q23) includes flood-plain (aQ23), fluvio-lacustrine (alQ23), marine-eolian (mvQ23) and marine-swampy (mbQ23) sediments.

2.2. History of geological development

Based on the UNESCO’s classification of the World Heritage, among the four criteria, the Phong Nha - Kẻ Bàng area has potential value as criteria (1) and (4) to become natural world heritage. The first one is geodiversity.

- Geological structures. The Phong Nha - Kẻ Bàng area has a diverse and complicated geological structure with five basic synclines and five basic anticlines: 1) Đồng Hới dome-like anticline with the core of Cambrian rocks; 2) Đại Đủ anticline with the core of Lower Devonian rocks; 3) Đông Ph­ơng anticline with the core of Middle Devonian rocks; 4) Cao Mại anticline with the core of Early Devonian rocks; 5) Rào Nậy graben; 6) Quỳ Đạt syncline; 7) Phong Nha syncline; 8) Thác Dài - Ma Rai syncline; 9) Trung Thuận syncline.

- Faults. There are two main fault systems and two secondary fault systems. The two main systems are NW-SE and NE-SW trend and the two secondary systems are of longitudinal and latitudinal trend.

- The Earth’s crust has undergone five tectonic megacycles corresponding with the five geological evolution stages of the world. They are: Late Ordovician - Early Silurian Stage (about 450 Ma); middle-late Devonian Stage (about 340 Ma); Carboniferous-Permian (about 300 Ma); Mesozoic Orogenic stage and Cenozoic stage.

2.3. Geomorphology

In general, there are two groups of landforms in the Phong Nha - Kẻ Bàng area. They are non-karstic and karstic landforms.

Non-karstic landforms can be divided into three types as follows:

- The middle and low dome-block mountains developed in intrusive magmatic massifs;

- The middle denudation-structural mountain belts developed in terrigenous rocks of Cretaceous age;

- The low block-denudational mountain belts developed in other terrigenous rocks

Karstic landforms in Phong Nha - Kẻ Bàng area are of typical tropical karst. They can be divided into two groups of forms as follows:

- The karstic forms on the surface including cone and tower karst, karrens, valleys and dolines, border polje, etc;

- The underground karst consisting of caves.

There are two main systems of caves and some other ones in Phong Nha - Kẻ Bàng area. They are Ṿm and Phong Nha cavern systems. The total length of the surveyed caves in this area is about 85 km (Table 2).

Table 2. List of the caves in Phong Nha - Kẻ Bàng

V̉M CAVERN SYSTEM

No

Name of cave

Length (m)

Height (m)

1

Ṿm Cave

15 050

145

2

Đại Cáo Cave

1 645

28

3

Maze (Duat) Cave

3 927

45

4

Cá (Fish) Cave

1 500

60

5

Hổ (Tiger) Cave

1 616

46

6

Over Cave

3 244

103

7

Pymy Cave

845

94

8

Ruc Carrong Cave

2 800

45

9

Dany Cave

250

30

10

Water Melon Cave

400

25

Total

31 277

 

PHONG NHA CAVERN SYSTEM

No

Name of cave

Length (m)

Height (m)

1

Phong Nha Cave

7 729

83

2

Tối Cave

5 558

80

3

E Cave

736

0

4

Cha An Cave

667

15

5

Thung Cave

3 351

133

6

En Cave

1 645

49

7

Khe Tiên Cave

520

15

8

Khery Cave

18 902

141

9

Khe Thi Cave

35

20

10

Phong Nha Khô (Dry) Cave

981

25

11

Lạnh (Cold) Cave

3 753

114

12

Cá (Fish) Cave

361

14

13

Dơi (Bat) Cave

453

-24

Total

44 391

 

OTHER CAVES IN QUẢNG B̀NH PROVINCE

No

Name of caves

Length (m)

Height (m)

1

Rục Ṃn Cave

2 863

49

2

Tiên Cave

2 500

51

3

Chén Chuột Cave

279

15

4

Minh Cầm Cave

246

15

5

Thông cave

193

10

6

Ban Co Cave

144

6

7

Khai Cave

100

5

8

36 Cave

140

38

9

Cây Tre Cave

160

5

10

Factory Cave

150

0

11

Dơi (Bat) Cave

125

25

12

La Ken I Cave

30

0

13

La Ken II Cave

250

10

14

Ton Cave

30

0

Total

7 410

 

The specific features of the cavern systems are as follows:

- There are long river caves, especially Khe Ry Cave of 18 km long. So that, it is the longest single river cave in South-East Asia.

- Caves are developed in massive pure limestone, thus forming many intersecting systems of different ages.

- There are now five levels of cavern entrances at different elevations above the local eroded level as 0 m; 20 ± 5 m; 50 ± 10 m; 100 ± 10 m and 200 ± 50 m. There are four level in Over cave as 0 m; 24 m; 43 m and 93 m.

- The stalactites and stalagmites are beautiful, fantastic; there are many generations of stalactites and stalagmites superimposed on each other with the age corresponding to that of the cavern levels.

3. BIODIVERSITY

1. Forest

Based on the FAO (1986) classification of vegetation types, in Phong Nha - Kẻ Bàng area there are eleven vegetation types and subtypes as follows (Table 3).

Table 3. Forest vegetation types of Phong Nha - Kẻ Bàng area

No

Vegetation types

Code

Area (ha)

%

1

Tropical dense moist evergreen forest on limestone under 800 m a.s.l.

2.1

112,476

74.7

2

Low tropical montane evergreen forest on limestone above 800 m a.s.l.

1.1

12,600

8.5

3

Tropical dense moist evergreen forest on hills under 800 m a.s.l.

2.1

12,220

8.3

4

Low tropical montane evergreen forest on hills above 800 m a.s.l.

1.2

1,070

0.7

5

Degraded evergreen forest on limestone

2.3

1,641

1.1

6

Degraded evergreen forest on hills

2.3

4,212

2.8

7

Tree and shrub savanna on limestone

2.8

1,925

1.3

8

Tree and shrub savanna on hills

2.7

2,950

2.0

9

Riverine forest

2.6

180

0.1

10

Bamboo forest

2.5

150

1.0

11

Cultivated land

2.9

521

0.3

Total

 

147,945

100

2. Flora

The flora of Phong Nha - Kẻ Bàng area is representative of the transition zone between two big floristic regions: the northern and southern regions. This area is the southernmost locality of some species of the northern floristic region, such as Burretiodendron hsienmu and Platanus kerrii. The area is also northernmost of some species of the southern floristic region such as Dipterocartus kerrii and D. grandiflorus.

In particular, Phong Nha - Kẻ Bàng area is a center of endemism. The site supports 13 plant species which are endemic in Việt Nam (Table 4). For example, the narrowly endemic species Sao đá (Hopea sp.) is confined in the site. It is a new species and will be described in a near future.

Table 4. List of endemic plant species in Phong Nha - Kẻ Bàng area

No

Scientific name

Vietnamese name

1

Burretiodendron hsienmu

Nghiến

2

Cryptocarya lenticellata

Nanh chuột

3

Deutrizanthus tonkinensis

Mọ

4

Eberhardtia tonkinensis

Mắc niễng

5

Heritiera macrophylla

Cui lá to

6

Hopea sp.

Sao đá

7

Illicium parviflorum

Hồi núi

8

Litsea baviensis

Bời lời Ba V́

9

Madhuca pasquieri

Sến mật

10

Michelia faveolata

Giổi nhung

11

Pelthophorum tonkinensis

Lim xẹt

12

Semecarpus annamensis

S­ng nam

13

Sindora tonkinensis

Gụ lau

 

Among the recorded plant species, 38 are listed in the Plant Red Book of Việt Nam (1996) and 25 species are listed in the 1997 IUCN Red List of Threatened Plants

3. Fauna

Preliminary faunal surveys have identified 568 vertebrate species of 132 families, 44 orders, comprising 113 mammal species, 81 reptile and amphibian species, 302 bird species and 72 fish species (Table 5).

Table 5. List of animal species in Phong Nha - Kẻ Bàng area

Taxon

Orders

Families

Species

Mammals

11

28

113

Reptiles&amphibians

3

24

81

Birds

18

57

302

Fish

11

23

72

Total

43

132

568

 

The fauna of Phong Nha - Kẻ Bàng area is representative of the northern Tr­ờng Sơn Range and is closely related to the Indian and Myanmarese faunas. Among species recorded at the site, there are 568 animal species listed in the Red Book of Việt Nam and 44 species listed in the IUCN 1997 Red List of Threatened Animals (Table 6).

Table 6. List of threatened animals species in Phong Nha - Kẻ Bàng area

Taxon

Red Book of Việt Nam (1992)

Red List of IUCN
(1997)

Mammals

35

19

Birds

15

19

Reptiles&amphibians

18

5

Total

68

44

 

Notable characteristics of the Phong Nha - Kẻ Bàng fauna are:

- The fauna of the Phong Nha - Kẻ Bàng is very rich in species, especially mammals, with many threatened species such as tiger, bear, elephant, giant muntjac, wild dog, leopard, etc. The numerous caves, abundant food sources and low human population density provide good habitat for several primate species.

- Ten species and subspecies of primates have been recorded at the site equivalent to 45.5% of the total number of Vietnam’s primate species. All these species are listed in Decree 18/HĐBT dated 17th January, 1992 of the government, and seven of them listed in the Red Book of Việt Nam. The site supports four endemic primate species in Indochina, namely Trachypithecus francoisi hatinhensis, Pigathrix nemaeus, Hylobates lencogonis and Nictycebus coucang. In particular, the site supports the total world population of Trachypithecus francoisi hatinhensis.

Mammal. Among the 113 mammal species, 35 are listed in the Red Data Book of Việt Nam (1992), 19 species are listed in the 1997 IUCN, Red List of Threatened Animals. Two newly discovered large mammal species Mang Lớn (Megamuntiacus vuquangensis) and Sao La (Pseudoryx nghetinhensis) are also found in the Phong Nha - Kẻ Bàng area.

Birds. Phong Nha - Kẻ Bàng supports 302 species from 57 families and 18 orders, including 15 species listed in Red Book of Việt Nam and 18 species listed in the 1997 IUCN Red List of Threatened Animals. In particular, there is good evidence for the Lophura hatinhensis and Lophura imperialis species at Phong Nha - Kẻ Bàng area.

Reptiles and amphibians. Initial field-surveys in Phong Nha - Kẻ Bàng area have recorded 59 reptile species belong to 16 families and 2 orders, and 22 amphibian species belonging to 6 families and 1 order. Among these species 18 are listed in Red Book of Việt Nam and 6 species are listed in the 1997 IUCN Red List of Threatened Animals.

Fishes. Comparing with other Vietnam’s protected areas, Phong Nha - Kẻ Bàng area has the greatest number of taxa, with 72 species belonging to 23 families and 11 orders. In the Phong Nha - Kẻ Bàng area, there are many different fish habitats. Four strictly endemic fish species have just been discovered that are known only in Phong Nha - Kẻ Bàng or a neighbouring area. These species include Chela quangbinhensis. The eel fish Anguilla bengalensis is an economically valuable fish species found at Phong Nha - Kẻ Bàng. This species is found in the caves, along the rivers and in streams. In the Phong Nha - Kẻ Bàng area, every year, fishers catch about 30-70 of this fish species.

Butterflies. An initiative survey by Vienamese-Russian Tropical Centre (funded by WWF) recorded 259 butterfly species of 11 families. Almost all major butterfly taxa in Việt Nam can be found in Phong Nha - Kẻ Bàng area.