Taiwan is located off the southeastern coast of mainland China, separating the East and South China Seas, and boarding the Pacific Ocean in the east. The climate is warm (average annual temperature is 18 degree) and humid (average annual precipitation is 2500 mm). This small (36,000 km2) and very mountainous island has approximately one third of its land area higher than 1000 m above sea level. The central mountain range, which runs from north to south, reaches a maximum height of about 4000 m. This range forms a great barrier to air parcel movement and thus represents one of the important factors that regulates the climate and ecology of both the west and east slopelands. Associated with this disruption of air circulation, Taiwan experiences almost annual summer typhoon landfall. The high winds and heavy rain associated with typhoon represents a major disturbances to Taiwanese ecosystems. For example, on 31 July to 1 August 1996, typhoon Herb contributed nearly 2000 mm rainfall in the Mt. Alishan area in the central range of Taiwan. Other major natural disturbances are frequent landslides and a high rate of soil erosion resulting from fast crustal up-lifting associated with weakly consolidated sedimentary rock formations.
Changing land-use patterns and pollution are two major anthropogenic impacts that influence both natural ecosystems as well as populated urban areas. Little systematical research has been done in Taiwan to explore the effect of these disturbances on the impacted systems.
Forests cover about 60 percent of the total land area of the island of Taiwan and thus constitute the predominant terrestrial ecosystem. Due to the rapid uplifting of the island, lakes are relatively few and of small areal extent. Therefore the five TERN sites include four forest sites and one alpine lake site. The sites differ in geography, geology, climate, and vegetation types and represent the range of important ecosystems of Taiwan.
Major Factors affecting ecosystems of Taiwan include:
Typhoon
This is one of the most influential forces that shape and regulate Taiwan's ecosystems. Three-quarter of Taiwan's annual rainfall of 2500 mm or 100 inches occurs during typhoons, whose season is between June and September, occasionally stretching into October. For example, typhoon Doug (August 10-11, 1994) dumped around 800 mm (32 inches) of rain, while typhoon Seth (October 8-10, 1994) dumped around 630 mm (25 inches) of rain. In addition, strong winds associated with typhoons are very destructive. The ravages of typhoons are numerous but little known.
Unstable
geological formation
Taiwan experiences rapid crustal uplifting rates -- up to about 40 mm in northeastern Taiwan, with an average of no less than 10 mm per year islandwide. This results in high rate of soil erosion, extensive and frequent occurrences of landslides, channel sedimentation, and reservoir siltation.
Air pollution
The effects of local and regional on sparsely populated natural ecosystems have received little attention. Effects of acid deposition on forests is one of the research areas under TERN.
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Natural
Environment of Taiwan
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