PartⅤ

Previous Works of IGCP 448 Participants Relevant to the Project

1. Comparison of Karst Ecosystems

Some initial data on karstic ecosystem in Vietnam
---Example of Cuc Phuong National Park

Dr. Tuyet, B.Sc Dinh Xuan Quyet
Research Institute of Geology and Mineral Resources, Ministry of Industry, Vietnam. Address: Thanh Xuan, Ha Noi, Vietnam.

Setting on tropical karst of Vietnam

Karst of Vietnam is typical for the tropical humid region. It is the continuance of the tropical karst belt of the world and closely related to tropical and subtropical karst of South China and tropical humid karst of Southeast Asia. In Vietnam, karst occupies about 60,000km² and consists of main zones. Those are the Northeast, the Viet Bac, the Northwest, the North Central and some small areas in the South. Among them the Northeast zone is a mixture of continental and marine environment or the coastal karst, the rest are the continental or continentally dominant ones. Karst of Vietnam is formed on host rocks mainly consisting of limestone, dolomite and marble in some cases. They belong to different formations ranging from Late Cambrian to Middle Triassic with fairly pure composition and are intensively affected by folding and faulting activities of various tectonic cycles.

The distinctive characteristics of the tropical humid karst of Vietnam are: high temperature (both in water and soil) with mean value of 23℃, high comparative air humidity of more than 95%, high rainfall with annual average of 2,000mm and up to 3,000mm in some places and a long lasting rainy season; well-developed cave systems with large dimensions and complex structure, which are a favorable environment for wildlife, the presence and development of big and long underground cavern rivers of which the Toi is one of the longest in the world; the presence of peak cluter-depression and peak cluster valleys; especially the presence of thick evergreen rainforest of tropical monsoon climates making them ecologically attractive for research and tourism. Cuc Phuong National Park, presented hereafter, is a fairly typical example of the natural ecosystem on tropical humid karst and still well preserved.

Some data on the karst ecosystem in Cuc Phuong National Park

The Cuc phuong National Park located in Ninh Binh province is the SE part of the NW karst zone with area of 22,220 ha. It borders to the fluvial plains in the SW and NE. The park is outstandingly landscaped by the peak cluster-depression and the peak cluster-valleys. Elevation ranges from less than 200m to more than 500m and the highest summit is 648m (May Bac peak). The peaks have relative heights of 100-300m. Dolines, closed depression are deep, the valleys prolong in NW-SE direction. The slopes are often steep or sometimes are the scarps. The karstified rock is pure limestone of Dong Giao formation of Middle Triassic, 800m thick and strongly affected by folding and faulting activities. The Buoi is the only surface river running through the park in NE-SW direction. Underground water is fairly rich in the caves and procaves, at a depth of 30-50m. There is a spring near the park gate. Studies on the karst ecosystem are being carried out there. The initial results are presented below:

1 On the plant kingdom

The lower plants are not botanised well. The higher plants (Cormobiota) are reported to be abundant, comprising of 1,853 species from 896 genera, 224 families, 86 orders and 7 phyla(table1).

The Cuc Phuong’ s plant system is diverse, of which the Cormobiota’s representatives occupy 31% of total Cormobiota of north and 24% of Cormobiota of the whole Vietnam territory. The woody trees are the richest with the absolutely superiority of representatives of magnoliophyta (Angiospermae), the next ranks are the shrubby, weedy and ligament or climber plants. Nguyen Nghia Thin (1995) observed 19 plant communities belonging to 3 formation classes. These plants form a world of a tropical lush rainforest green all year round with a five-layer structure:

Table 1 Cormobiota in Cuc phuong National Park ( source: Le Vu Khoi, 1994 )

No	Phylum	Class	Order	Family	Genus	Species	Proportion(%)
1	Bryophyta	3	9	31	75	125	6.36
2	Psilotophyta	1	1	1	1	1	0.05
3	Lycopodiophyta	2	2	2	2	9	0.49
4	Equiserophyta	1	1	1	1	1	0.05
5	Polypodiophyta	3	7	27	55	129	6.97
6	Pinophyta	3	3	3	3	3	0.16
7	Magliophyta	2	63	159	759	1, 583	85.42
Total:		15	86	224	896	1,853	100

The highest layer (Al) or emergent height of 50 to 75 m and 2 to 7m in diameter with scattered distribution. Some typical species are Parashorae chiensis, Aglia gigantean, Annamocarya chiensis, Cinnamonum balancae, Terminalia myriocarpa, Heritiera macrophilla, Pterospermun sp., Diospyresmum, Chukraria tabularis, paviesia annamensis.

canopy consists of woody trees with 0">The layer A2 is composed of woody trees of 40-50m high and makes out a 0">Layer A3 is a canopy with plants of 10-20 m high and 0">Layer A4 consists of plants below 8 m high with 0">Layer A5 (forest floor) consists of weedy and shrubby style="font-size:12.0pt">Besides,

2 On the Animal kingdom

Investigation of faunas in Cuc Phuong National Park currently focuses on the Chordata phylum. The initial results specify a list with 439 species from 84 families, 37 orders and 4 classes(table 2).

Species of the Arthropod phylum such as insects, diptera, spiders etc are abundant and diverse with 1,800 species from 200 families and 30 orders. The animal kingdom here has many precious and rare groups like Pantera tigris, Neofelis nebulosa, Chrotogale owstoni, Pavo maticus, Polylectron briealcaratum. Among them there are more than 50 species of mammals of big and medium size. Some species such as Selenaretos thebetanus, Hylobates concodor, Trachipythecus francosi delacouri are endemic ones and considered as symbols of the park. Some others such as Trachipythecus phreyrei, Nycticebus pygmacus, Manis pentadactyla are marked in the

Table 2 Cordata in Cuc Phuong National park
(source: Vo Quy et al, 1996; Le Vu Khoi, 1994 )

No	Class	Order	Family	Species
1	Mammals	17	25	71
2	Birds	16	42	319
3	Reptiles	3	12	33
4	Amphibians(frog and tadpole)	1	5	16
4	Total:	37	84	439

RED BOOK of Vietnam. Rhinotophus rouri and Scotomanes omatus, two new species of bats in Vietnam, have been first discovered in Cuc Phuong.

Species of birds are abundant. Among them, there are 70-80 species of the order Passerifomes. Some typical species such as Garrulax cnarus, Garrulax chinensis, Lanius schuch, Passer montanus, Pericrocotus flammenus, Alcedo bicornis, Anthracoceras malabaricus, Pavo muticus, Polyplectron bicalcaratum, Lophura nycthemera are rare and precious.

Among 17 species of snakes, there are many venomous ones such as Naja Hannah, Naja naja, Bungarus fasciatus, B. candidus, Trimeresurus mucroquamatus. There are 13 species of lizards, among them Draco sp., is flying one.

References

Le Vu Khoi, 1994, Model for the construction of villages at the buffer zone of Cuc Phuong national Park. Ministry of Forestry, Hanoi, Vietnam.
Vo Quy, Nguyen Ba Thu, Ha Dinh Thuc, Le Van Tac, 1996, Cuc Phuong National Park, Agr. Publ. House, Hanoi Vietnam.
Thai Van Trung, 1965, Characters of Cuc Phuong National forest, The Forest No.3-4, P.29-36, Hanoi ,Vietnam.

The Ecological Environment Regionalization in Karst Area
--- a case study of Houzhai Basin in Puding couty, Guizhou province

Wang La-chun^① , Shi Yun-liang^① , Wang Wen-fu^② ,Yang Yong^② , Chen Hong-yuan^②

(①Department of Urban and Resources Science, Najing University, and State Pilot
Laboratory of Coast and Island Exploitation, Nanjing University, Najing 210093, China)
(②The Karst Experiment Station of Puding County, Guizhou Province 562100,China)

Abstract: Karst mountains are widely distributed in south-west China where the ecological environment is fragile and the economy is undeveloped. In this paper, a case study of ecological environment regionalization at Houzhai Basin in Puding county, Guizhou province is introduced. Based on the study of regional indication of the ecological environment in the area, the 4 regions are divided by applying cluster analysis method. The ecological environment characteristics are described and the regulation modes are suggested in every region. This method of regionalization can be applied in other karst areas.
Carsologica Sinica, 2000, VOL.19 , NO.1, P.96

Geoecological studies on the karstic surface of the planned Protected Area in Western Mecsek, South Hungary

Edit Hoyk

Earlier studies on the karst in Western Mecsek have already shown that this area is worth protection due to its quite well preserved natural state. In consequence, declaring the karstic territory with its wider environment as a protected area is being considered in the Danube-Drava Natural Park. In order to prove the almost untouched natural state of an area good starting point is to examine its soil and flora. Soil studies focus on determining the pH, detecting any tendency of a shift towards lower pH values and on examining the carbonate content. In the future measurements to check the heavy metal content that are especially suitable for showing the levels of anthropogenic contamination will be added to these studies. Investigations on the flora based on the examination of water balance, soil reaction and determination of the rank according to the categories of nature conservation value offer a support to the claim of being protected. The results show that indirect anthropogenic effects can be detected by the pH shift towards lower values, but the same tendency of turning acidic is less characteristic in dolines which are the most sensitive points of karst field. However, the relatively high carbonate content favours the resistance against felling pH values. Examining the vegetation, and paying special attention to the ranking into nature conservation categories, a significantly high ratio of association-forming and accompanying species and the presence of protected species in relatively high numbers can be seen that proves the nature conserving feature of the territory. On the basis of the investigations carried out the maintenance of the present state of the territory is a desirable objective and in order to realize it the protection of the area is absolutely justified.

The Mecsek Mountains are the southernmost mountain range of Hungary. There are three adjoining karstic areas in its western part: near the villages of Abaliget and Orfü, and in the Melegmany Valley. These three areas are part of the Western Mecsek Mountains Protected Area proposed by the Danube-Drava National Park. The southern part of this Area is covered by sandstone, so that is not part of our project(Fig.1).
The intensive karstic processes began in the Pleistocene and have been continuous till today (LOVASZ 1977), which can be proved by the high number of dolinas which are still forming.
There have been geoecological examinations of the area near Orfü, which are now extended to the Abaliget and Melegmany areas.
The goal of the examinations, which concentrate on the soils and the flora, is to prove that these areas are worth protecting. There had been similar research in the Aggtelek karstic region and in the Bukk Mountains, too (KEVEINE 1983).
The pedological examinations were carried out in laboratory conditions. The vegetation, however, was inspected on site.
The pedological examinations consisted of the analysis of pH-value, carbonate- and heavy metal-content.
The pH-value of the soil is acidic, the average value is 5-6. The graph shows that the average pH in the Melegmany area is a little bit higher, and there are more values around neutral. This can be explained by the higher carbonate content of the soil here. The acidic pH is natural, because these soil types(the main type of soil is brown forest soil with clay washed in) usually have such a pH value (STEFANOVITS 1975).

fig.1 Karst areas of Hungary

2. Karst Vegetation

Rock Desertification in the Subtropical
Karst of South China

Yuan Daoxian

Summary: An overview of world karst indicates that most karst environmental problems, especially rock desertification, occur mainly in tropical and subtropical karst terrains. Population pressure and some malpractices in land use have intensified the processes of rock desertification. In Guizhou Province, the annual rate of rock desertification in karst areas was as high as 933 km² in the 1980s, although in recent years, many projects to tackle with this fragile environment in south China have been implemented. Measures such as in harnessing underground streams, ecological rehabilitation, and comprehensive development in the poorest karst regions of South China have proved to be successful. However, ecological conditions there vary from place to place as a result of geological, climatic, and topographic differences. Consequently, more research and improved management are necessary for better planning and more effective implementation of rehabilitation measures.

1 Introduction

Rock desertification refers to the processes which transform a karst area that was covered by vegetation and soil into a rocky landscape almost devoid of soil and vegetation (Fig.1).It is a serious ecological problem in the subtropical karst regions of South China (Fig.2)and it leads to progressive impoverishment of the local residents. A similar process has occurred in other parts of the world, such as in Southeast Asia and in the Mediterranean basin. The fragility of the karst ecological system in tropical and subtropical regions is the basis of rock desertification, but the vicious sequence of events is triggered by human activities including population pressure, bad land use planning and practices, and air pollution. In recent years, key projects supported by government and international communities to mitigate the problem have been implemented. A series of countermeasures are proving to be successful. However, more research is necessary to underpin the measures being taken.

Fig. 1 The landscape of rock desertification on hillsides near
Liangsuatun village, Anshun, Guizhou Province.

Fig. 2 Areas affected by rock desertification in southwest China

2 The fragile ecological system of the subtropical karst of south China

2.1 The recognition of karst fragility

The ecologically fragile karst system is characterized by droughts, floods, soil erosion, rock desertification, surface collapse, limited biodiversity, low primary productivity, and poverty of human life. According to the results of IGCP 299 "Geology, Climate, Hydrology and Karst Formation"(1990-1994), the rock desertification in south China is a part of the fragile world karst ecosystem belt that extends from the Mediterranean, through the Middle East and parts of southeast Asia to the central Americas. Karst has been recognised as a fragile environment by the scientific community since at least 1983, when a symposium entitled "Degradation and Rehabilitation of Fragile Environments: Karst Areas and Desert Margins" was held at the 149th Conference of the American Association for the Advancement of Science (AAAS 1983). A similar symposium took place in the same year in Guizhou, China.

The warm humid climate of the south China karst with mean annual precipitation values ranging between 1000 and 2000 mm and mean annual temperatures of 15-21^oC is very favourable for forest (the natural vegetation) and agriculture. The ecological fragility originates from the particular geological environment associated with karst processes, although the vicious land degradational sequence taking place in recent years is associated with human activities.

2.2 Geological Background and Ecology

Karst processes are controlled by the system CO₂--H₂O--CaCO₃ . It is an open triphase disequilibrium system and very sensitive to environmental change(YUAN 1997, this volume). The major geological factors that predispose the south China karst to fragility are :

(1) the low soil forming capability of soluble rocks, especially pure carbonates, and their relative shortage in nutritive elements. This results in thin soils with low fertility which readily succumb to rocky desertification, when soil erosion takes place under improper land management. To illustrate this affect, areas of rock desertification in the karst of Guizhou Province expanded at an average rate of 933 km²/a during the 1980s (YANG,1988).

(2)The double spatial structure formed after prolonged intensive karstification. This brings about not only loss of surface water and dessication, but also floods when the subsurface drainage capacity is insufficient during storms. Consequently, farmlands in the south China karsts are subjected to alternating droughts and inundation. Small patches of soil accumulate in dolines at the expense of centuries of erosion from surrounding rocky slopes. But vegetation can hardly grow on such soil because of its repeated inundation year after year. Thus reverse "timber lines" can often be seen in depressions in the south China karst, especially in the great expanses of fengcong depressions (Fig.3). Under favourable climatic conditions, forest can grow on the higher bare rocky slopes. But because of the shortage of soil, trees develop very deep root systems to get moisture and nutrition from rock fissures, and even from underground streams.Mosses and algae are usually the pioneer plants that help vegetation establishment in such inhospitable conditions with little or no soil. Through biogenic processes a thin water-bearing layer is formed on the surface of carbonate outcrops(CAO et al.1995). Its moisture absorption or releasing capacity can be 3-15 times higher than that of bare fresh rock (Fig.4). Under natural conditions, trees establish themselves on thin water bearing layers such as this, and develop into forests, but re-establishment is very difficult once cleared.

On the other hand, the species selection that occurs in karst micro-ecological systems characterized by thin soil, shortage of water, and alkaline conditions involves petrophile, xerophile, and calciphile species of the subtropical karst forest, thus limiting potential biodiversity. Table 1 shows the results of a comparison between the Maolan karst forest in Libo county, southern Guizhou, and the Mangshan Forest on granite in southern Hunan Province. Both of them cover about 200,000 ha and are located at a similar latitude and are subject to similar climatic conditions. The table shows that the species of pteridophyte, gymnosperm and the total wood storage in the Maolan Karst Forest are only 20-50% of those in the Mangshan Forest on granite.

Fig. 3 The formation of a "reverse timber line" in south China karst. An example from Longrui doline, Longgang Nature Reserve, Ningming County, Guangxi (Yuan,1993).

Table. 1 Species comparison between Maolan Karst Forest, southern Guizhou, and Mangshan Forest on granite southern Hunan (JIANG 1996)

Location	Lithology	Area (10⁴ ha)	Species of pteridophyte	Species of gymnosperm	Species of angiosperm	Species of vascular plant	Wood storage (10⁴.m³)
Maolan	carbonate rocks	19.37	31	13	757	801	134
Mangshan	granite	20.00	>100	60	850	>1000	248