應用遙測技術評估玉山國家公園之植生退化潛勢

Estimating the Potential of Vegetation Degradation Using Remote Sensing in Yushan National Park of Taiwan

玉山國家公園成立於1985年，迄今已將屆30年，園區內之森林植生在國家公園依法經營管理之下，其演替變化為何？實務上有必要進行調查及分析，但廣闊的園區調查不易。本研究以1990及2013年之衛星影像，結合遙測、地理資訊系統與主成分分析方法，進行森林植生變遷之分析。研究結果發現天然災害的干擾為造成植生退化之重要因子，尤其莫拉克風災所形成的退化區位，多分布於南部園區之水系周邊，另藉由植生退化的分布與環境因子資料，產生植生退化潛勢分布，並劃分為高、中、低等級，其中屬高度等級者多出現在一般管制區，因此，有必要注意該計畫分區未來之發展趨勢。除此之外，有許多地區雖尚未有嚴重的植生退化情形發生，然其區位同樣座落於高度退化潛勢等級，亦須特別因應與防範。

It has been nearly 30 years since Yushan National Park was established under the National Park Law of Taiwan in 1985. Vegetation succession in the Park, however, has yet to be further understood to facilitate management efforts. In light of the high cost entailed by a large-scale ground-level study, in this study techniques of remote sensing, geographical information system and principal component analysis were integrated to estimate the vegetation change from 1990 to 2013 in Yushan National Park. The results demonstrated that decreased vegetation was more likely to occur adjacent to southern streams due to impact of typhoon Morakot in 2009. We used spatial patterns of degraded vegetation and environmental data, which came out with three levels to classify rankings of degradation, namely, high, medium and low. The results indicated that in addition to existing use area, most areas classified as high level included pristine vegetation coverage. These findings may provide insights for future land management.