Taiwan is located about 130 km off the southeastern coast of mainland China and has an area of 35,960 km2. About two-thirds of the islands is occupied by mountains, and there are more than sixty peaks that exceed 3,000 m in elevation. Taiwan has a subtropical and tropical climate with an annual precipitation ranging from 2,124 mm to 3,575 mm and mean monthly temperature ranging from 12.4 to 20 C. The diverse environmental conditions and habitats result in a great diversity of flora and fauna. Forest covers about 520f the total land area of Taiwan and forms the predominant terrestrial ecosystems, which comprise hardwood forest, conifer forest and grassland ecosystems. In addition, in the estuary area of the western coast, there is a unique mangrove forest ecosystem, which possesses a great diversity of marine organisms. Little attention has been paid to natural conservation and ecological studies of the island until the last decade. Rapid industrial development and extensive human activity as well as natural disturbances, e.g. typhoons, soil erosion, and landslides are common, and persistent forces change and regulate the species composition, structure, stability, and productivity of ecosystems in Taiwan. Long-term monitoring of ecological factors and a database of the environmental parameters would be very useful references for decision makers, particularly in environmental policy and regulations. Long-Term Ecological Research (LTER) is thus particularly necessary for sustainable development in Taiwan.

Under the support of the National Science Council (NSC), the Council of Agriculture (COA), and Academia Sinica (AS) of Taiwan, five research sites -- Fushan, Yuenyang Lake, Guandaushi, Nanjenshan, and Tatachia -- were declared in 1994. More than 60 research projects (e.g. about 1.8 million US dollars for the fiscal year of 1996-1997) have been supported by the NSC, except for the one at Yuenyang Lake, which has been supported by the AS since 1992.

The main obiectives of LTER in Taiwan are (1) to understand long-term ecological changes in Taiwan, (2) to elucidate the mechanisms involved in ecological processes, (3) to provide suitable ecological information for social and economic development, and (4) to merit membership in an international LTER network in order to provide ecological information of regional and global interest. Taiwan LTER studies have put emphasis upon the structure and function of the forest ecosystem as well as on the hydrological and nutrient ilux of that ecosystem. The database will also be made available to those who participate in the global change research program.

Taiwan Long-Term Ecological Research

1. Fushan Forest Ecosystem

The Fu-Shan Forest site is operated by the Fu-shan Research Branch, Taiwan Forestry Research Institute, and the site is situated in the Harpen Natural Preserve located in I-Lan county in northeastern Taiwan, approximately 35 km south of Taipei city. The geographical location lies at 24 46'N and 121 43 'E. The subtropical climate is warm and humid with wet summers and frequent fog. Annual precipitation averages 2,900 millimeters (mm), 700f which occurs during the summer season. Mean annual temperature ranges from 4 C to 28 C with an average of 20 C. The annual relative humidity averages 88%, varying from about 75 0n the winter to nearly saturation in the summer. The prevailing wind direction is SE during summer and NE during winter. The site is 1,100 ha in size and ranges from about 400 to 1,400 meters in elevation. Three subwatersheds have been delineated within the Har pen-chi watershed. The bedrocks are mainly weakly metamorphized sedimentary rocks of Oligocene to Miocene in age and consist of argillites interbeded with fine sandstones. Soils developed from either residual or colluvial materials. Two subgroups of soils are identified. The subtropical moist forest is regarded as pristine in condition and is composed predominantly of Lauraccae and Fagaceae associated with lush epiphtyes and abundant understory vegetation. Major tree species are chinkapin (Castanopsis carlesii var. sessilis), red machilus (Persea thumbergii), yellow basket willow (Engelhardria roxburghiana), Chinese meliosma (Meliosma squamulata), litsea (Listsea acuminata), narrow leaved oak (Cyclobalanopsis longinux), gold colored neolitsea (Neolitsea sericea) and Pyrenaria shinkoensis. Common shrubs are predominantly blastus (blastus cochinchinensis) and tree fern (Alsophila podophylla). Understory vegetation is mainly herbs consisting of ferns (Dipluzium petri and Pleocnemia rufincrvis) and Elatostema lincolatum. The first six years' study concentrates on establishing plots (such as gauging subwatersheds, meteorological stations, long-term vegetation plots etc.), monitoring abiotic variables (climate, hydrology and soils moisture regimes etc.), surveying and carrying out inventory for flora, fauna and microorganisms of the site. Some functions/processes of the forest ecosystems (elemental budgets and cyclings, nutrient movement in the riparian zones etc.) are being conducted.

A team of 16 principal investigators, was initially organized by coordinator, Dr. C. H. Chou, and later succeeded by Dr. H. B. King. The research has been supported by the NSC of Taiwan since 1992. The next 3 years (1997-1999) will then focus on developing a dynamic landscape model based on the data obtained. It is hoped that the ecological model based on the integration of the aforementioned studies can be fruitful in predicting the effect of global change on the forest ecosystem in Taiwan.

2. Yuenyang Lake Ecosystem

The Yuenyang Lake Ecosystem study is conducted on at the Yuenyang Lake Natural Preserve site located in the northeastern part of Hsinchu county, at the uppermost head water of the Tahan River watershed with an elevation of 1650-2432 m. The total area of the natural preserve is about 374 ha, of which the lake is about 3.6 ha and the marsh area encircling the lake is about 2.2 ha. The surrounding hillsides are dominated by valuable cypress forest. The climate is temperate heavy moist.

The purpose of this natural preserve is to protect the unique forest ecosystem, comprising some endemic species of flora and fauna and its magnificent landscape. Because of the unique system, a team research program has been organized by the present author and involves seven principal investigators, who are researchers of the Institute of Botany, Academia Sinica, Taipei. The program has been supported by the Institute since 1992. The Yuenyang Lake Ecosystem Program focuses on (1) the mechanism in the formation of dominant vegetation in the preserve, (2) the primary productivity of the dominant vegetation, (3) the model of the nutrient cycle within the ecosystem, (4) the physiological study of aquatic plants, and phytoplankton, and (5) the adaptive mechanism of dominant marsh plants. In addition, several other individual researchers from other institutes have been involved in studies on atmospheric chemistry, such as acid precipitation, and acidic lake mechanisms. The significant research findings based on the aforementioned five objectives are given as follows:

Concerning the vegetation here is unique comprising three dominant communities, namely a) Potanzogeton octandrus, Sparganium faller, and Schoenoplectus mucronatus. b) Miscanthus transmorrisonensis, Schoenoplectus morrisonensis and Rhododendron mariseii - Rhamus cranata, and c) Chamaecyparis formosensis and Chamaecyparis obtusa var. formosana, for which the mechanism of dominance has been investigated. Both allelopathy and competition are involved in determining the dominance of vegetation.

Comparing the photosynthetic rates of the dominant aquatic plants, it was found that the metabolism was quite different from that of temperate forest species growing at the same altitudes.

The nutrient budget of the forest ecosystem is under investigation. The status of carbon and nitrogen in soil is crucial for establishing a model of energy flow in the lake ecosystem. The research has involved a general survey of the soil and of the biomass of microorganisms in the forest soil and in the swamp sediments.

An acidified lake, Yuenyang Lake was investigated to study the relationship of the resources of phytoplankton and epilithic algae to the acidic environment. The study aimed to find a way to use algae as a bioindicator of acidification in the environment and to reconstruct the paleolimnological environment in this lake. Diatoms are the dominant algae throughout the year. The species appearing in the lake are typical acidophiles, such as Eunotia, Tabellaria, Frustulia, Pinnularia and Anomoeoneis. The changes in the species composition of diatom assemblages in the surface sediments are found to be related to the pH gradient of the lake water measured between the eastern inlet and outlet. This suggests that these species can also serve as an indicator of pH change in the environment.

The Yuenyang Lake area is 3.3 ha and its maximum depth is 4.5 m. The population dynamics of two dominant aquatic plants, Sparganium fallax and Schoenoplectus mucronatus were studied. The different patterns of growth and metabolite translocation in these two aquatic plants growing in different habitats of the same region revealed differences in adaptation strategy. For example, the relationship between free absicic acid (ABA) levels and shoot elongation was investigated in shoots of Scirpus mucronatus L. Under submergence, shoot elongation increased, but free ABA levels decreased. The results indicate that ABA is an internal inhibitor of shoot growth in Scirpus.

Furthermore, changes in polyamine biosynthesis in relation to submergenceenhanced shoot elongation were determined in shoots of Scirpus mucronatus L. The increases in free putrescine and shoot elongation in submerged shoots diminished from the base to the apex. The increase in free putrescine in submerged shoots was coincident with the increase in shoot length. These overall results indicate that arginine decarboxylase (ADC-) and ornithine decarboxylase (ODC-) mediated putrescine synthesis are essential for the elongation of Scirpus shoot grown under submergence.

3. Guandaushi Forest Ecosystem

The Guandaushi LTER site situated at the Nantou County of the center Taiwan, is located in a 47-ha watershed with elevation from 1,100 to 1,700 m. The mean temperature is about 25 C, and the annual rainfall is about 2,700 m with distinct rainy and dry seasons. This forest station was established in 1949 and is currently operated by the National Chung-Hsing University and designated for teaching, experimentation, as well as the demonstrative management of economic forests, protected forests and forest recreation. The research approaches here are similar to those of the Fushan site. There are 12 principal investigators, involving scientists from various disciplines. Dr. M. Y. Chen has been serving as coordinator.

Typhoons occur occasionally during the period from June to September and bring a great amount of rainfall but sometimes it damage the forest. This LTER site represents a typical subtropical forest in central Taiwan, which is characterized by steep topographies, abundant riparian ferns, virgin hardwood forests, and abundant epiphytes at stratified forests. The forests at ridges have been deforested and planted with Chinese fir.

The Guandaushi Forest Ecosystem program has been fully supported by the NSC since August of 1994. The goal of this program is not only to understand the structure and function in a subtropical forest ecosystem in central Taiwan, but also to reveal the possible effects of changing environments on biotic species and ecological processes. The current program includes studies on forest vegetation, dependent plants, fish communities, mammal communities, amphibian and reptile communities, insect fauna, basidiomycetes, hydrological models, hydrochemicals, and nutrient cycling.

Most of our research, particularly the hydrological model and nutrient cycling, are carried on at the selected watershed area and its adjacent areas, including Schima reserve, Calocedrus reserve, Guandaushi basin, and a site where a forest accidentally burned in 1992 has received considerable research attention.

Regarding the vegetation structure and function of the Guandaushi forest ecosystem, a total of 917 species of vascular plants were found in the forest. These included Pteridophyta (121 species), Gymnospermae (20 species) and Angiospermae (776 species). Six permanent plots (20mx 25m each) were established. All trees with DBH > 5cm were measured, tagged and mapped. Lauraceae and Fagaceae were the most important families of woody plants. The dominant understory shrubs were Rubiaceae, Mysinaceae and Theaceae. Inventory on the vascular epiphytes (dependent plants) at stratified forest has also been carried out. In addition, more than 900 species of vascular plants were recorded, including rare species, such as Brania formosana, Rhododendron lasiostylum, Litsea rotundifolia var. oblongifolia, Lindera aggregata, Pasania nantoensis, Helicia rengehensis, Castanopsis eyrei and Cyclobalanopsis globosa, etc. Two natural preserves were set up to protect Schima superba and Calocedrus formosana.

The heterotrophic organisms play essential roles in the influence of the dynamics of forest ecosystems. Thus, the studies on the diversity of mammals, amphibians and reptiles, fishes, insects, and Basidiomycetes were conducted.

The hydrology study is one of the most important aspects of research on the forest ecosystem. The primary objective of this research at the site is to understand the hydrological model of the watershed. Meteorological instruments were installed at the site for a long-term observation.

Furthermore, the studies of the biogeochemical cycle at the site include (1) hydrochemicals at the riparian zone, (2) biomass productivity and nutrient cycling, and (3) soil microbial ecology and nutlient cycling.

4. Nanjenshan Forest Ecosystem

The Nanjenshan LTER site is situated in the Kenting National Park at the southern tip of the island with its unique tropical and subtropical forests, exhibiting an ecotone vegetation of Taiwanese and the Philippines. A relatively small Nanjen Lake on the site is ideal for studying the effect of environmental change on the forest and lake ecosystem.

The Nanjenshan Forest Ecosystem Research Program was started and has been coordinated by Dr. Y. L. Kuo since August 1, 1995. In its first year, there were 14 research projects, dealing the inventory of plants, animals and microorganisms, and the monitory of environment changes of this site. The Nanjenshan ecosystem is greatly influenced by northeastern monsoon that persists for four months during winter season. Forest physiognomy may shift from tropical rain forest to temperate forest, where the elevation rises from 200 m to 480 m. Forest composition changes completely with every 300 m rise in elevation. A canopy photosynthesis study was conducted to estimate primary productivity, and the influence of sunflecks on the growth of understory seedlings was also investigated. As for zoological inventory, only 8 species of mammals and 45 species of birds were found in this area, significantly less than in other tropical forests. Others included 16 species of amphibians, 21 species of reptiles and 74 families of 15 orders of insects. For non-insect invertebrates, 15 species were recorded under natural forest and l l species under secondary forest. Depth of soils ranged from 60 cm to 130 cm with clay texture on the top and clay loam beneath. Soils were very acidic (pH value was about 4.5) and poor in nutrient contents. However, the pH value of precipitation averaged 5.92, indicating that there were no acid rains in the study area. About 30 ha of the lake is sedimentary, and the lake possessed 386 species of phytoplankton and 60 species of zooplankton. The pH value of the water and dissolved oxygen showed an apparent diurnal variation pattern. The kinds and amount of methanogens, sulfate reducing bacteria, and sedimentary bacteria in anaerobic condition were under investigation.

5. Tatachia Montane Ecosystem

Tatachia Montane Ecosystem, the fifth site of LTER, is located in the central part of Taiwan, (23.5N, 121E). Elevation of this site is about 2500 m above sea level. Average annual precipitation is 3700 mm, most of it occurs between June and September, while November to January is a distinct dry season. Average temperature is 7.7 C in January and 16.1 C in July; frost is normal occurring from November to February. As the region is humid and foggy, montane temperate conifers and grassland prevail. This site is a part of the Experimental Forest of National Taiwan University and it's also in the range of the Yu-shan National Park.

Geologically, it is unstable and fragile. The bedrock is metamorphosed sedimentary rocks of Miocene Epoch, composed mainly of sandstone and shale. The soil develops poorly because of the steep, erosive terrain. It consists of colluvial eithosol and podzol mixed with visible rocks. Wet and sticky soil is only found deeper in mild slope areas.

The vegetation in Tatachia represents a typical cool temperate area of Taiwan. Morrison spruce (Picea morrisonicola) and Chinese hemlock (Tsuga chinensis) are both dominant, while Taiwan red cypress (Chamaecyparis formosensis) and armand's pine (Pinus armandi) are co-dominant. On the other hand, Yushan cane (Yushania niitakayamensis) and alpine silver grass (Miscanthus transmorrisonensis) are dominant as post-fire grasses, where Taiwan red pine (Pinus taiwanensis) is a pioneer tree species.

Wildlife is abundant at this site, especially formosan rock-monkey (Macaca cyclopis), mikado pheasant (Syrmaticus mikado) and formosan salamander (Hynobius formosanus). However, a newly constructed highway runs through the area and the tourism has had a great impact on it.

The primary objectives of this study are to understand the structure and functions of montane temperate conifers and grassland, and to reveal the effects of environmental change on biotic species and ecological processes. Some permanent plots have already been set up. Several sub-projects, including studies on forest and grassland vegetation, bird and mammal communities, insect fauna, microorganisms, hydrological budgets, soil nutrient dynamics, nutrient cycling, microhabitats, plant physiology, and human impacts are being conducted. In the 1996-1997 fiscal year, there are 13 projects being carrying out, and more than 20 researchers from various institutions, such as National Taiwan University (NTU), Experimental Forest of NTU, and Academia Sinica, etc., are involved.

Promotion of Taiwan LTER Activity

Under the auspices of the National Science Council of Taiwan, a special program to promote the LTER has been established since August 1995. The present author serves as the National Coordinator of the research. The LTER has been recognized as one of the important projects and was selected as one of four main theme topics of the 16th Annual Meeting of Science and Technology Advisory Group (STAG) of Executive Yuan of Taiwan. As a result of the STAG Meeting, the LTER should receive more support from the Council. Additionally, several recommendations were proposed to the Council. In order to expedite LTER research and to promote future collaboration between scientists from Taiwan and abroad, an Ecological Research Center at Academia Sinica was proposed. The present author thus invited ecologists and environmental experts to hold meetings in order to plan such an organization for LTER in Taiwan.

In addition to the improvement of infrastructure of LTER in Taiwan, each LTER site has invited every principal investigator (PI) to a monthly round table discussion involving graduate students and assistants in order to accelerate the research.

We are proposing that an International LTER workshop should be held in Taiwan as a satellite meeting for the 26th General Assembly of International Union of Biological Sciences during November 17-23, 1997. In order to increase public awareness of the importance of LTER, we have published four issues of the TLTER Newsletter in Chinese since October 1995. In addition, an Introduction to the Taiwan LTER in English will be published in June 1997. Research findings from each site have been placed on the World Wide Web to make further intellectual communication between scientists possible and to promote better international connectivity.

Conclusion

The aforementioned five LTER sites in Taiwan provide information regarding representative forest and lake ecosystems in the subtropical and tropical region of Taiwan. The Taiwan LTER program is also in the scope of IGBP and is much related to the international scientific programs, such as Global Change and Terrestrial Ecosystem (GCTE) and Diversitas, which was recently established by the IUBS, SCOPE and UNESCO. The research findings are available for scientific interest and the guidance of government in improving forest management. They are valuable for the ecological and environmental education that may increase our people's awareness of the importance of natural conservancy.

Acknowledgements

The author would like to extend his appreciation to Drs. H. B. King, M. I. Chen, Y. L. Kuo, and K. C. Lee, who are the coordinators of each LTER site in Taiwan, providing the valuable information we are concerned with. Great acknowledgment is due to the National Science Council, the Council of Agriculture, and the Academia Sinica. Taiwan for financial support of these studies.