The Reconstruction and Monitoring of Long- and Short- Term Environmental Changes by the Use of Fossil and Living Plants
Geography Dept., KyungHee University
Seoul, 130-701, KOREA
Present work aims to reconstruct the long-term(geological) environmental and vegetational changes of the Korean Peninsula based upon plant fossils, both macroscopic and microscopic data. Research also intends to develop the biogeographical indicators for the monitoring of short-term climatic and environmental changes, especially in connection with the climatic change by the use of living plants, such as arctic-alpine and alpine elements, which are sensitive to global warming.
Palaeo-vegetational data are collected from 40 sites for the conifers and taxads, and 75 sites for the dicotyledons from both South Korea(ROK) and North Korea(D.P.R.K.). Data are analysed within the time-frame from the Permian period of the Palaeozoic era to the present day and presented chronologically for the time-spatial analysis. Current floristic and phytogeographical data on the distribution of cold-loving plants are collected and collated from many high mountains of Korea to detect the short-term environmental changes. Intensive field surveys both on the distribution of arctic-alpine and alpine plants and temperature recording at 1,700 and 1,950m a.s.l. have carried out on the summit of Mt. Halla, Cheju Island from 1995 to 1997.
2. Vegetational and Environmental Changes During the Geological Period
Though the oldest plant fossil in Korea(Neuropteris) dates back to the Carboniferous period, the appearance of oldest conifers in Korea discovered at Sadong, ROK and dates back to the Permian period of Palaeozoic era and includes Elatocladus, Ullmannia and Walchia. In case of dicotyledons the oldest floristic data date back to the Cretaceous period of the Mesozoic era in Korea and include seventeen genera e.g., Platanus, Viburnum, Populophyllum, Tabeinidium, Phyllites, Zamiophyllum, Salix, Populus, Nelumbies, Menispermites, Cinnamomum, Legminoisites, Ilex, Rhamnites, Grewia, Aralia and Lindera. Seven genera i.e., Platanus, Viburnum, Salix, Populus, Cinnamomum, Ilex, Grewia, Aralia and Lindera still grow naturally in wild.
The first appearance of many of the present-day floristic genera indeed dates back to the Oligocene period. The presence of thermophilous genera such as Myrica, Ficus and Hedera in the Oligocene at up to four degrees north of their present distributional limits implies that the climate of the Oligocene was warmer than that of today.
The occurrence of similar thermophilous floristic element at up to six degree north of present range during the Middle Miocene suggests a maximum northward expansion of warmth-loving evergreen broadleaved vegetation, for example Cinnamomum, Cyclobalanopsis and Ilex for the recent Korean vegetation history. The continued occurrence of numerous present-day genera since the Oligocene period indicates a long-term stability of Korean vegetation, along with minor fluctuations within it.
The admixture of evergreen coniferous plants e.g. Taxus, Abies and Thuja and deciduous broadleaved plants indicates a probable temperate climate for much of the Middle Pleistocene of Korea. The presence of cold-episodes during the Upper Pleistocene might has caused a general expansion of deciduous broadleaved plants and cryophilous evergreen coniferous plants as well as the southward expansion of cryophilous arctic-alpine and alpine floras in Korea. The disappearances of some cryophilous genera, such as Pinus(Haploxylon), Picea, Abies, Larix and so on from 10,000 years B.P. marks the continued climatic amelioration since then, along with minor climatic fluctuation during the Holocene period.
Overall, the continuous appearances of both conifers and taxads since the Permian period of the Palaeozoic era as well as dicotyledons in Korea since the Mesozoic era, despites the sporadic hiatus of fossil data indicates the absence of catastrophic environmental changes in the past which ensure the long-term climatic stability, along with minor climatic fluctuations within it and the presences of both environmental and habitat diversities at present.
3. Recent Changes of Alpine Plants on Mt. Halla, Cheju Island
The alpine plants of Mt. Halla, Cheju Island, Korea can be divided into eight groups based upon their horizontal and vertical distributions, and include (1) species solely grow on Mt. Halla(15 spp.), (2)species common to northern Korea and Mt. Halla(14 spp.), (3) species common to Mt. Sorak and Mt. Halla(5 spp.), (4) species common to Mt. Chiri and Mt. Halla(7 spp.), (5) species common to Mt. Sorak, Mt. Chiri and Mt. Halla(40 spp.), (6) species which are endemic to Mt. Halla or Korea(27 spp.), (7) species common to numerous Korean mountains and Mt. Halla(22 spp.), (8) species common to Japan and Mt. Halla(6 spp.).
Out of the numerous alpine plants of Mt. Halla four arboreal species(Juniperus chinensis var. sargentii, Diapensia lapponica subsp. obovata, Empetrum nigrum var. japonicum and Vaccinium uliginosum) and four herbaceous species(Pedicularis verticillata, Scabiosa japonica form. alpina, Anaphalis sinica subsp. morii and Leontopodium coreanum), respectively have been selected to delimit the horizontal and vertical distributional ranges and also to monitor the minor changes of their range.
Seventy percents of the alpine plants of Mt. Halla, which do occur in the Korean Peninsula and Japanese Islands may indicates the previous floristic connections between two areas in the past, probably through the former land-bridge. The presence of alpine flora on Mt. Halla must primarily be attributed to historical factors, since it can not be wholly explained by reference to present environmental conditions. The alpine flora of Mt. Halla are evidently descended from immigrants from NE Asia via the Korean Peninsula and eventually moved down to the Japanese Isles during the epoches of the Ice Age. These plants, which are very intolerant of competition with the temperate vegetation on mild conditions, have been able to persist in alpine area thanks to their harsh climatic conditions, sterile soil, rugged topography and cryoturbation of Mt. Halla in which they are more competitive. Current distributional ranges of eight alpine plants are confined to near the summit of Mt. Halla. Detailed horizontal in the Korean Peninsula and vertical ranges on Mt. Halla are as follow: Juniperus chinensis var. sargentii occurs at Mts. Seungjuk(1,600m - ), Peenanduk(1,000m - ), Myohyang(1,600m - ), Sasoo(1,600 - 1,740m), Chuae(1,500m -), Kumkang(1,000 - 1,600m), Sorak(700 - 850), Chiri(1,400 - 1,900m.), Dokyoo(1,400 -), Kaya and Halla(1,900 - 1,950), and growing slopes and altitudes of Mt. Halla are East(1,920 - 1,700m), West(1,940 - 1,550m), South(1,920 - 1,500m) and North(1,900 - 1,670m) ; Diapensia lapponica subsp. obovata is found at Cheju Island, and growing slopes and altitudes at Mt. Halla are West(1,800- 1,850m) and North(1,850m) ; Empetrum nigrum var. japonicum occurs at Mts. Paekdoo, Kwanmo, Turyu, Puksoobaek and Halla, and growing slopes and altitudes of Mt. Halla are East(1,920 - 1,500m), West(1,940 - 1,200m), South(1,920 - 1,400m) and North(1,900 - 1,200m) ; Vaccinium uliginosum grows at Mts. Paekdoo(1,200 - 2,540m), Kwanmo, Mantap(2,000 - 2,300m), Hamjiwon, Pujonkowon, Myungdangbong, Hwangsoowon, Turyu, Puksoobaek, Robong(1,700 - 2,000m), Hoochiryung(800 - 1,200m), Kumpaeryong(1,300 - 1,600m), Myohyang, Nangrim(1,900 - 2,200m), Sasoo(1,800 - 1,860m), Kumkang(1,000 - 1,680m), Sorak(1,500 - 1,700m), Konbong and Halla and growing slopes and altitudes at Mt. Halla are East(1,920 - 1,700m), West(1,930m), South(1,910m), North(1,850m) ; Pedicularis verticillata occurs at Mts. Paekdoo, Kwanmo, Turyu, Puksoobaek, Robong, Pujonkowon, Sorak, Chiri and Halla, and growing slopes and altitudes at Mt. Halla is West(1,940m); Scabiosa japonica form. alpina exists at Mts. Myohyang and Halla, and growing slopes and altitudes at Mt. Halla are East(1,880m), West(1,700 - 1,500m) and South(1,800-1,750m) ; Anaphalis sinica subsp. morii is found at Mt. Halla, and growing slopes and altitudes at Mt. Halla are East(1,900 - 1,850m), West(1,900 - 1,500m), South(1,900 - 1,760m) and North(1,850m) ; Leontopodium coreanum occurs at Mts. Chail, Kumkang, Sorak, Sobaek and Halla and growing slopes and altitudes at Mt. Halla are West(1,900m) and South(1,900m). The comparison of previous data which published during c. 1960', 1970' 1980' with present distributional ranges indicates that the alpine plants of Mt. Halla surveyed are on the stage or process of retreat toward the mountain top, probably due to the recent climatic amelioration.
Overall, palaeo-biogeographical and current phyto-geographical data seems to provide useful informations for the better understanding of long-term and short-term environmental changes of Korea. Continuing works on the palaeo-environment and thermal amplitudes of alpine elements on Mt. Halla may provide good information, which may helpful to establish the impact of the short-term environmental changes of the Cheju Island, and enable to develop a criteria for the selection of biogeographical indicator of temperature warming trend.
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