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Part I Progress of IGCP 448 in 2000 ¡¡ By Yuan Daoxian(Karst Dynamics Laboratory, Guilin, China) ¡¡ 1 Summary of major past achievements of the project IGCP 448 is a successor project of IGCP 299 ¡°Geology, Climate, Hydrology and Karst Formation¡±(1990-1994) and 379 ¡°Karst Processes and the Carbon Cycle¡±(1995-1999). Previous works related to karst ecosystem are summarized in the 92 page first issue of IGCP 448 Newsletter (2000), and are available on our website. (http://www.glnet.edu.cn/KDL/IGCP/IGCP448/2000/index.htm) The major past achievements of the Project could be summarized according to the 4 main objectives of IGCP 448.
From the experiences of UK, Mediterranean realm, the Middle East, South China, Southeast Asia and Central America, it is generally accepted that karst ecosystem is fragile. This is the results of soluble rock dissolution which brings about the development of underground drainage system, and thus shortage in soil and water on the surface. In some part of the world¡¯s karst regions, the area of rock desertification is expanding. However, such fragility is differed at different part of the world with different geological, climatic, and vegetational background. For instance, in some boreal or temperate humid karst regions, such as Kungur, Southeast of Perm, Russia, underground karst system is good for agriculture because it can drain away excess water in wetland, and the carbonate rocks can buffer acid water of bogs. The function of Eucalyptus forest on hydrogeoecology in the karst regions of Southeast Australia is not to increase the water storage in the aquifer, but rather to mitigate soil salinization problem by lowering down groundwater table through its strong evapotranspiration. Therefore, it is necessary to carry out systematic comparison on world karst ecosystems, so as to enlighten knowledge on the mechanism of how different types of karst ecosystem coming into being, and thus benefit more reasonable treatment of ecological problems and sustainable development in karst.
It has been recognized that the karst vegetation is charactered by Petrophile, Xerophile and Calciphihe in those areas where soil cover is very thin, and the underground drainage system is well developed. Thus the biodiversity is limited. On the other hand, many petrophile species are precious. Plants such as the Lonicera hypoglauca Miq, Nervilia fordii(Hance) Schltr, and Eucommia ulmoides are herb medicines, but they are found growing only in areas of particular geochemical background with certain kind of effective trace elements. The karst vegetation is also effected by lithological features of the carbonate rocks, e.g, the old phase (pre-Triassic) hard compact carbonate rocks in mainland China is less favourable for soil formation and water detention than those young phase (Tertiary) porous soft carbonate rock in Central America and Southeast Asia, hence the ecological problem of the former is worse than the latter. There are also plant invasion problems in karst regions, such as the bracken in Yorkshire, UK; Eupatorium adenophorum in South China, and the Kudzu Vine in Appalachian, USA are spreading over the karst regions, and restrain the growth of other useful plants.
The geographical distribution of the subterranean ecosystem research in karst is uneven. Europe and North America is more advanced in general. Thousands of cave-dwelling species from about 82 caves in USA have been studied. In Europe, the Societe Internationale de Biospeologie was founded in France about a hundred years ago. The involvement of the Society into IGCP 448 with its current Chairman Dr. Giuseppe Messana (Firenze, Italy) as the Co-leader of the Project, and its newly edited Encyclopaedia Biospelogica will enhance interdisciplinary study in this direction. In China, cave fishes in more than 20 caves in the central and western past of Guangxi Province were studied systematic in early 1980s. In recent years, more studies were carried out on the threats to cave ecosystem. It is considered that the most important threats to cave habitat are changes in water and nutrients, and, to lesser extent, to toxic chemicals, oxygen loss and more direct impacts such as collecting, mining, and caving. Some special cave fishes, Typhlobarbos mudiventris; and Triplophysa geijuensis in Jianshui County, Geiju County of southern Yunnan Province are endangered because of over extraction of water from caves. The Sinocyclocheilus hyalinus in Luxi county, Yunnan province is endangered because of tourism boating on the underground stream. Cave flora and fauna are used for karst environmental and hydrological study. For instance, the cave salamanders Typhlomolge rathbuni and Typhlomolge robusta can be used to distinquish different pools of the Cretaceous Edward Karst Aquifer, Texas, USA. The composition of hypogean and epigean species are used to study the structure of karst aquifer in typical sites of southern and eastern France. The microflora indicated by Total Viable Counts (TVC) is used to trace the type of percolation (swallet, conduit or fissure) into the G. B. Cave, Somerset, UK. It shows great potential in this direction.
Many previous works dealt with the interaction between karst ecosystem and land use. The development of underground drainage system and geochemical features of limestone can restrict the biodiversity in karst. The flood in karst depressions limits the forest and agriculture, for instance, only early-maturing wheat can be grown in Gubeng Polje, Xichou County, Yunnan, south China because it is flooded in the summer by underground stream. On the other hand, there are a lot of works on the impacts of human activities (quarrying, mining, agriculture, timbering, urbanization, water conservancy, and etc.) on the karst ecological system. But how to achieve sustainable development in karst and mitigate geohazards, especially karst collapse remains a great challenge. ¡¡ 2 Achievements of the project in 2000 2.1 General scientific achievements (including societal benefits) In the first year of this Project, organization works went smoothly. Besides the 110 participants from 31 countries of IGCP 379 who will continue to be involved in the new project, 21 registration forms were received, which provided 14 new sites for international correlation. The suggested new karst ecosystems include tropical, subtropical, temperate, and Mediterranean types, protected or deteriorated. A conceptual model of karst ecosystem was worked out as the basis of methodologies for world correlation. It includes the structure, driving force and function of a karst ecosystem. The five-year detail plan of the project is defined. Concrete achievements of the project this year as reflected in the presentations of symposia, field workshop and reports from National Working Groups are summarized according to the 4 objectives of the project as followed. 2.1.1 World comparison of karst ecosystems Two major field correlations took place this year in northwest Romania, a Mediterranean karst system, and Lagoa Santa Karst, Eastern Brazil, a Gondwana subtropical karst system. Moreover, Vietnamese Working Group reported a tropical karst ecosystem in Cuc Phuong National Park, and Slovenia WG reported Skocjanske Jama world heritage site, another Mediterranean karst ecosystem. In northwest Romania, 7 caves were visited at Bihor Mountain karst including an ice cave (Scarisoara) with a big block of permanent ice; the longest cave of Romania, the Vantului (wind) cave (48 km long); and the Ursilor cave, a scientific reserve cave with late Pleistocene- Holocene bear fossils (Ursus spelaeus). The excursion also included some karst springs, and a typical karst region (Padis region, 37 km2) with many dolines, swallow holes, and sinking streams. The vegetation of Bihor Karst is in general very good in comparison with many other karst regions of the world, nevertheless, anthropologic impacts in some parts are very strong, especially in the areas of timbering, grazing and mineral deposit prospecting. In the excursion at Lagoa Santa Karst, Eastern Brazil, the Palmeiras karst plateau (700m asl) and Mocambeiro depression, 3 caves, 3 karst lakes, 2 blind valleys and sinking streams, one karst spring and a big limestone quarry were visited. Overall, the Lagoa Santa Karst represents a typical karst landform, but as it is developed on the bases of Proterozoic carbonate rock; a stable Gondwana land surface; and a subtropical climate (annual mean temperature 230C, and annual rainfall 1380mm), it enjoys some special features: (1). Long time of denudation on a stabler low relief land brings it a generally thick red soil covers (more than 10 m); (2). Numerous limestone cliffs at the base of dolines, with frequent occurrence of lakes at their base; (3). Lakes showing a complex hydrogeologial behaviour; (4). Caves showing evidence of paragenetic development, and numerous phases of sediment input and removal. Moreover, heliotropical stalagmites are usually seen on the entrance. The vegetations of Lagoa Santa Karst are characterized by subtropical and Gondwana, and can be classified into three types. The Savanna (Cerrado) vegetation occupied originally most of the area, having been replaced by grasslands suitable for cattle farming. Cerrado vegetation is now restricted to isolated pockets in the area. Semideciduous forest occurs associated to dolines and limestone cliffs. The Cuc Phuong National Park is located in Ninh Binh Province of Vietnam with an area of 22,220ha. It is underlain by Middle Triassic pure limestone 800m thick. The annual mean temperature is 23 ¡æ, with annual mean rainfall 2000mm. The elevation ranges between 200m and 640m and is featured by typical tropical karst landform, the peak cluster-depression. The vegetation here is a combination of indigenous species and migrant species from Himalaya, South China, Malaysia and Pacific Islands. The park is good at biodiversity, with 1853 species of Cormobiota plants. There are 407 species with medical value, 250 species of food plants, and 115 bonsai species. Moreover, the fauna there are also very rich, with 439 species of Chordate Phylum, and 1800 species of Arthropoda Phylum. Two new species of bats, Rhinotophus rouri, and Scotomanes Omatus are first discovered in Cuc Phuong.The world heritage site Skocjanske Jama is located in the Classic Karst of Slovenia. The region is underlain by Cretaceous-Tertiary limestone with typical karst features, such as poljes, dolines and big cave systems. The surface karst ecological system is in good condition, with a vegetation cover up to 45%. Moreover, karst setting has strong impact on human life. They are different in Triassic dolomite region or in Cretaceous-Tertiary limestone regions, and also different in low land of polje or on karst plateau. The word ¡°karst¡±(¡°kras¡±in Slovenia language) where the scientific discipline karstology came from means ¡°bare rock¡±. But such landscape no longer exists in the exact Classic Karst area now. The history of vegetation recovery in the region during the past century is a good example for world correlation on karst ecosystem. By investigating the sedimentation layers in typical dolines of Divaca Karst, western Slovenia, Andrej Mihevc reconstructed the course of human impacts on karst environment back to 5000 years BP, and classified it into several stages: burning down forest at the beginning (5000a BP); and then artificial flattening the doline bottom and cleaning rock from slope in Roman time. He found that the human activities were intensified after the 10th century, and reached a maximum in the 18th century. 2.1.2 Geological background of karst ecosystem and vegetation Iancu Oraseanu reported that in the Misid brook karst region of Northwest Romania, the general HCO3-Ca-Mg water changes into Ca-SO4 water with PH value up to 3 because of the local oxidation of pyrite by percolating water. Jianhua Cao (China) found that the water-bearing capacity of a carbonate rock surface can increase remarkably when it was reformed by Crustose lichens. This process is quite favorable for ecological rehabilitation of a rock-desertified karstland. Velasquez, L.N.M (Brazil) found from the study in the karst region of Mid-Southern Minas Gerais State, that the lithofacies formed by calcarenite are more susceptible to develop secondary porosity and karstification, and can thus create a more favorable hydroecologial condition. Ivo Karmann reported that under the long term denudation of the stable Gondwana land with a subtropical humid climate, karst features including dolines, collapse valley, kamenitzas, karren and sinkholes are well developed in Phanerozoic sandstones and Proterozoic quartzites of Cratonic covers and fold belts. There are 170 mapped caves in the siliceous rock of Brazil, ranging between several meters and 3.5 km long. Some contain opal speleothems, including dripstone, flowstone, rimstone dams and crust. During the excursion in NW Romania, we learned that the Bihor karst is an ideal site for world correlation on karst ecosystem because its biodiversity is a result of many controlling factors including geography, lithology, topography and Cenozoic history. Geographically, it is at the meeting place of Northern, south-Mediterranean, south-Balkan, central-European, Oriental and Eurasion species as well as of endemic and relict ones. In the Padis area, the plant communities are dominated by Sesleria rigida and Avenastrum decorum, both of them of great value for the Carpathian vegetation. The grasslands of Sesleria rigida are an important link in the grassing of rock and karst aforestation. In the limestone slope, one can find pioneer herbaceous communities of calcicol plants dominated by Dryopteris robertiana, Galium erectum, Thymus Comosus, etc. On the rocky belts and poljes develops a xerophyte vegetation dominated by Festuca Pallens, Melica Ciliata. The subalpine vegetation begins at the altitude of 1600m. The ligneous vegetation is represented by the dwarf-Juniper. The subalpine grass communities are dominated by Festuca rubra, Festuca Ovina, and Anthoxtantum odoratum. The Bihor karst vegetation also enjoys some relict species, such as the Tertiary relict of Transylvanian lilac (Syringa josikaea); the glacial relicts of Pedicularis limnogena, Eriophorum vaginatum, Empetrum nigrum, and Carex Pauciflora. 2.1.3 Subterranean Karst ecosystem New achievements in this field, including microbiology in cave and its impacts on weathering and depositional processes; behaviors of underground animals such as beetles, and some vertebrates; and description of cave fauna. Megan L Porter (USA) reported that the karst ecosystem in Movile cave, Southern Romania is a system that contains higher trophic level, which are entirely dependent on chemoautotrophic microorganisms. This makes it an excellent place for studying the ecology of sulfur-based ecosystem, i.e, better than deep-sea vent or deep groundwater aquifers for its accessibility. Moreover, the methane concentration in the Movile cave is approximately 1%(V/V). Elena Manolache et al tried to isolate and characterize the methanotrophic bacteria from the cave. On the other hand, the Villa Luz Cave in Mexico rich in Sulfur Hydrogen gas is another example of chemoautotrophic ecosystem based on Sulfur-loving organisms. Through works on some caves in Romania, Italy and USA, Annette Summers Engel (USA) indicates that there is considerable diversity in the populations of sulfur-oxidizing bacteria living in karst system, but their metabolic activity can have a significant impact on cave formation. By means of Mitochondrial DNA sequence analysis, Ruxandra Buzila (Romania) and Alfred Seitz (Germany) studied the phylogeography of cave beetles from Romania concerning their population structuring, speciation and evolutionary history, and recorded a cave cricket Troglophilus neglectus in SW Germany. Jacob Parzefall (Germany) studied the changes in the behaviours of some cave living vertebrates (fishes and amphibians), including their diurnal activity, alarm, aggressive, and sexual behaviours. By hybrid studies, he found that the differences between cave and surface forms are genetically based. Tudor Tamas found that the 1-30 mm thick black deposits in Cuciulata Pothole (NW Romania) are composed of amorphous aluminium gel-like material, amorphous iron and manganese hydroxides as main components. Its depositional mechanism is controlled by Eh and PH of the environment, and the presence of Iron-reducing bacteria. During a Sino-British Cave Expedition in Guangxi Province, China (2000 Summer), Arthur Clarke (Australia) found some cave fishes from Linyun county and Yangsuo county, which were identified by Zhou Jie(Guangxi Fisheries Research Institute) as parasilurus cochinchinensis (Cuvier et Valenciennes) and Parasinilabeo assimlis Wu et Yao. The former is a Stygobite with a very long whiskers, while the latter relies on algae on rock surface and is called by local people as ¡°oil fish¡± because it is fatty. 2.1.4 Human impacts on karst ecosystem The karst ecosystem of Lagoa Santa region is at present under heavy pressure of human activities, being probably the most endangered karst area in Brazil. Rapid urban expansion into the karst terrain, coupled with the ever increasing mining for cement plants represents a major threat to the region. Groundwater, soil and vegetation are under severe stress. Some karst lakes and rivers are polluted and unsuitable for human use. Berbert-Born M.L discussed the environmental impacts of human activities in this region (industrial and domestic waste recharge into lake, airport construction, and limestone quarry) with the informations provided by lake sediments. Pereira, R.G.F.A considered that the increase in catastrophic karst collapses in Una River Basin, Bahia, Brazil in the past 50 years were related to the intense deforestation in the region. Mining and quarrying have direct impacts on karst ecosystem. For instance, the Idrija Mercury deposit of Slovenia was exploited since 1500s, and used to be the second biggest mercury mine of the world (after the Almaden Mine in Spain). A total of 147,000 tons of mercury were extracted from here, which is more than 13% of the total world production of this metal. The Deposit was formed along a major, hundreds km long regional overthrust in NW direction, with wall rocks of Carboniferous beds being overturned on Triassic dolomite. Because of the sublimate nature of mercury, the Mine has brought about serious environmental problems to the area. We were told that about 20kg of mercury are emitted into the atmosphere per day, and giving rise to endemic deseases. The mine is being gradually shut down because of environmental awareness, the declining use of mercury and falling price of mercury as well as the impoverished ore deposit, although some 14,000 tons of mercury still remained. The Limestone Quarry near Koper is the third largest quarry of Slovenia. Its annual production is about 500,000m3 for use as aggregate or wave-broken stone in harbours. It exploites Pliocene limestone on a major nappe structure with elevation ranging between 420m and 340m. One of the main environmental concerns is that it is on the catchment area of several karst springs which are the source of water supply for local people. Moreover, it is located on the world renowned Classic Karst. The expanding of the quarry will inevitably destroy some karst features (macrospically or microscopically). In addition, the quarry has exposed some cave systems with unique sediments, which has particular scientific significance in reconstructing paleoclimatic change up to 1.7 million years. One of the remedial measures is to fill back the quarry pit with flysch material moved out during quarrying. The development of tourism is another source of disturbance to karst ecosystem. For instance, the opening of Hwansongul Cave, Taei Cave Zone, Samch¡¯ok city at eastern coast of South Korea has brought great economic benefit, but people are worried about the environment consequence of opening other caves, which is more marvellous but with more fragile speleothems. 2.1.5 Societal benefits
2.2 List of meeting with approximate attendance and number of countries
2.3 List of most important publication (including Maps)
2.4 Activities involving other IGCP projects or the IUGS
¡¡ 3 Proposed activities of the project for the year ahead ¡¡
4 Other information considered relevant ¡¡ http://ww.glnet.edu.cn/KDL). (2) Contribution to IHP. The Project prepared a manuscript of chapter 14 ¡°Hydrogeology of carbonate rocks¡± for the IHP- project M-1.3 ¡°groundwater studies¡±. We were informed from G.P.Kruseman that the book will come out soon. (3) The Project has established link with the Societe Internationale de Biospeologie, with its current chairman Dr.Giuseppe Messana (Italy) as Co-leader of IGCP448. It will help greatly the smooth running of the project, especially its 3rd objective: ¡°Subterranean ecological sysytem¡±. (4) The cooperation with Friends of Karst, an informal scientific organization of USA is continued. The 3rd joint meeting was held with success (July, 2000, Cluj, Romania). (5) The link between the Project and Working Group on Cave and Karst of LUCN (International Union for Conservation of Nature) and WCPA (Work Commission on Protected Areas) has been established through exchanging informations and coordinating works. (6) The Project continues to make contributions for Global Change study (IGBP), especially with informations of paleoclimatic change from karst records, and impacts of land use cover change on karst hydrogeology. |
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