The scientific achievements
of the Project's second year is characterized by an international
comparison of various karst ecosystem along a north-south transect
in East Asia, i.e. from tropical ones to boreal ones. Concrete achievements
of the Project this year could be summarized according to its 4 objectives(Yuan,2000)
on the bases of presentations and discussions in symposia took place
in Beijing, August 30-31, 2001, reports from National Working Groups,
and field excursion from September 1-12, 2001 in China.
1. World Comparison of Karst Ecosystem
Based on the 2001 field correlation in subtropical karst of SW China
and semiarid karst in western Beijing of North China, and integrating
with reports from Eastern Siberia (Russia), and tropical karsts of
Ryukyu Island (Japan), Vietnam, Malaysia, and Indonesia, the Project
got a whole transect of karst ecosystems in East Asia from tropical,
subtropical, coastal, semiarid to boreal karst ecosystems. This is
a major step for the Project toward understanding karst ecosystem
of the world. Yuri Trjzhtsinski reported the boreal karst ecosystem
used to enjoy shallow groundwater perched on permafrost, which support
vegetation. But global warming and series of reservoirs constructed
on Angara River since 1960s had brought about vanishing of permafrost,
draining of shallow groundwater, and damaging the boreal Forest. The
reservoirs also activate the dissolution of Cambrian evaporite-carbonate
rock formation, and result in serious karst collapse problems. Do
Tuyet finds the good biodiversity of tropical karst on Paleozoic and
Triassic carbonate rocks in Vietnam, e.g, the thick vegetation cover
of evergreen tropical rainforest enjoys approximately 2000 species
of cormophytes, the phylum chordatas is represented by 541 species,
and the Class Insecta has about 2000 species. But processes of rock
desertification, under the impacts of human activities, like those
occurred in SW China also happened in the karst of Northwest Vietnam.
Sambudhi Sudibyo discussed the tropical ecosystem of the karst belt
underlain by Tertiary limestone along southern coast of Java Island,
the Yogyakarta Province of Indonesia. Under the prevailing climatic
conditions marked with seasonal extremes of water and heat, the population
pressure, and bad land use planning have transformed the karst ecosystem
into a rocky barren landscape that almost devoid of soil and vegetation.
The remaining soils on karstland are confined in dissolutional fissures
or holes distributed in a patchy pattern between limestone outcrops
or boulders. Local peasants cultivate their soil like growing plants
in pots, the so-called "pot culture".
In the middle part of the great East Asia transect, China enjoys various
subtropical monsoon karst ecosystems, under different geological,
topographical, climatic, vegetational, and human activity background.
During the excursion in 5 typical sites, some particular species were
examined, e.g. in the Jinfo Mountain Nature Preserve, Chongqing city,
Cathaya argyrophylla,(Photo1) a living fossil of Cretaceous and Tertiary
now remaining only in China survived from Glaciations because of its
special geographical situation; Chimonobambusa utilis, a particular
species of bamboo with rectangular cross section; and Liriodendron
Chinese(Photo2), remaining only in North America and China, so being
considered an evidence of continental drift.
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Photo1 Cathaya argyrophylla
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 Photo
2 Liriodendron chinense |
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| The vegetation cover
in Liupanshui city on Guizhou Plateau is only 1.14% with severe karst
rock desertification(Photo3). |
 Photo
3 Rock desertification in Yangmei, Liupanshui, Guizhou
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is proved that years of vegetation protection in rock desert can help
ecological rehabilitation, which also improved the eco-hydrological
system, such as the formation of permanent epikarst spring in rehabilitation
area. Such springs can be source of water supply for villagers in
karst area which used to suffer from shortage of drinking water. The
karst Hydrogeological Experimental Site near Yaji village at east
of Guilin is now in a positive evolution stage from rocky desert to
secondary grass-bush vegetation, with Vitex negundo(Photo4), Loropetalum
chinensis(Photo5), Phyllostachys sulphurea, and Rosa cymosa as |
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Photo
4 The predominant species of vegetation
(Vitex negundo) in the Yaji
Karst Experimental Site, Guliin
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Photo 5 The predominant
species of vegetation(Loropetalum chinnensis) in the Yaji Karst
Experimental Site, Guilin |
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predominant species.
Some relationship between ecosystem, hydrochemistry and microclimate
were found. The monitoring data reveals, that following the recovery
of vegetation, the Pco2 in soil atmosphere and the Ca2+, HCO3- content
in karst water are all increased remarkably. Moreover, it is found
by data log that the conductivity in the borehole water is increased,
and Ph value reduced during a storm. The phenomena are considered
to be a result of pushing CO2 into the borehole by the storm water.
Meanwhile, the microclimate in the Site is still worse than in the
nearby karst forest on the boundary between Guangxi and Guizhou. For
example, the annual variation of temperature and humidity in the Site
is 33oC, and 80% respectively, but in the karst forest, they are only
18.3oC and 35%. Moreover, the temperature on the surface of bare limestone
in the summer could be as high as 58oC, a condition that very unfavourable
for the rehabilitation of karst rock desert.
2. Geology and Karst Ecosystem
Many species growing on carbonate rocks are identified as calciphile.
Some of them are useful for humanbeing, such as Zenia insignis chun,
Lonicera hypoglauca Miq, Camellia Kuding, Nervilia fordii(Hance) Schltr,
Eucommia Ulmoides. Others are harmful, such as Pteridium, Kudzu vine,
Euratorium adenophorum.Zhang Weiji discussed the formation type of
red soils in Yunnan Province of China and its relation with ecology,
especially with agriculture, forestry, water conservancy and environmental
protection. Dora Angelova reported the ecological consequences of
paleoearthquakes in the karst terrains along the Northern Bulgaria
Black Sea Coast: rearrangement of karst water basins; cave deformation
or collapse; intrusions of oil, gas and salt; and etc. Vyda Elena
Gasiuniene analysed the impacts of paleokarst and its reactivation
on ecosystems in Akmene and Karpenai of Northern Lithuania, including
change in water quality, geohazards and quarry. Hiroyasu Furukawa
and others found the high permeability of Quaternary coral reef limestone
at Ryukyu Island, Japan brings about severe water shortage due to
rapid leakage. Based on the research in Nongla, Guangxi, a subtropical
peak-cluster depression mountainuous village, Jiang Zhongcheng discussed
the relationship between element migration (K, Na, Ca, Mg, Si, Al,
Fe, Mn) in rock, soil, water and karst ecosyetem, especially the development
of precious medicinal herb.
3. Subterranean Karst Ecosystem
Some biospeleologic findings were got by Christian Lascu and Serban
Sarbu at Movile Cave, southeast coast of Romania. The cave is developed
in limestone of upper Miocene, with a passage a little lower than
modern sea level. Through diving in a siphon, a totally closed chamber
24m3 in volume was found to be dwelt by 1000 of cave animals from
33 species including centipedes and spiders. The closed condition
of the cavity with temperature 25-30oC and its high concentration
in methane(1%v/v) and H2S bring about the idea that the cave fauna
are entirely dependent on chemoautotrophic microorganisms. Li Wei
and Yu Longjiang screened out the subsoil bacteria that produce Carbonic
Anhydrase (CA) which can accelerate carbonate rock dissolution in
4 different karst ecosystems of SW China. It is found that the activity
of CA in subsoil bacteria is related to vegetation. Perrin J and others
reported results of investigating faecal bacteria in a karst aquifer
of Milandre Test Site, Swiss Jura. Tian Youping identified 188 species
of aerial blue algae on the surface of carbonate rocks in the Stone
Forest Resort, Yunnan, China, and discussed their actions on the formation
of micro karst features. Based on a study at Barkly Karst, Northern
Australia, Russell Drysdale reported his findings on the role of some
aquatic insect larvae (Orders of Diptera, Lepidoptera, Trichoptera)
in travertine building.
4. Effects of human activities on karst ecosystem.
Tan Boon-Kong provided an overview of karst engineering geology in
Malaysia, with special discussions on rockfall, sinkhole and karst
foundation problems. V. V. Tolmachev reported the karst hazards on
sulphate-carbonate rocks in the European part of Russia, and suggested
three protective measures for civil and industrial buildings. Milena
Samalikova discussed the karst formation at Moravia, Czech, and relevant
problems such as rock fall, sinkhole foundation, quarrying, and ecological
aspects of civil engineering works. Shane Fryer talked about the vulnerability
of karst terrain to contamination with a dramatic incident of 3800
gallons diesel oil leakage happened recently in the Mammoth Cave region,
USA.
The reciprocal changing of biodiversity in the Stone Forest area,
Yunnan, China in the past half century provides a good example of
relation between human activity and Biodiversity. People noticed that
in the center part of Big Stone Forest, the evergreen broadleaf endemic
flora are surrounded by uni-species artificial forest(pine trees).
It showed that the planting could bring about quick afforestation
on one hand, but reduction of biodiversity on the other.
The Lionne Karst Spring at Swiss Jura is a test site of COST Action
620, for Karst Hydrogeology and Vulnerability Study. It covers an
area of about 30km2, and underlain by Jurassic limestone. The discharge
of the spring ranges between 100 l/s and 8500 l/s. Two approaches
of vulnerability assessment and mapping for the karst system have
been worked out. The first one is the EPIK method. Vulnerability is
here defined as the intrinsic geological and hydrogeological characteristics
which determine the sensitivity of groundwater to contamination by
human activities. The EPIK method is based on a conceptual model of
karst hydrological system with 4 karst aquifer attributes: E-Epikarst;
P-Protective cover; I-infiltration condition; K-karst network distribution.
The application of this method in several sites in Switzerland resulted
in recommending new boundaries for karst water protection zone. Another
is the VULK model. It also takes into account the characteristics
of 4 layers in the catchment area. A contaminant transit time map
was demonstrated, and provides bases for vulnerability assessment.
The results of the two years of IGCP448 have shown that world comparison
on karst ecosystems has enlightened knowledge on the mechanism of
how different karst ecosystems coming into being, and will benefit
more reasonable treatment of ecological problems and sustainable development
in karst. It is therefore in keeping with the guideline of IGCP "Geoscience
in the service of society".
Reference
Yuan Daoxian, IGCP448, World Correlation of Karst Ecosystem(2000-2004).
Episodes, 2000, 23(4): 285-286
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