應用景觀指數評估地景變遷與其對水質及生態之衝擊-以台北水源特定區為例

Assessment of Landuse Change and Associated Impacts on Water Quality and Ecology by Employing Landscape Metrics -Case Study in Taipei Water Source Special District.

李元喻(Yuan-Yu Lee)

指導教授 ： 朱子偉 ； 譚智宏

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2013年)

https://doi.org/10.6841/NTUT.2013.00275

摘要

集水區土地利用之變遷，容易造成長期的水文及生態環境改變，然而此種變化往往是緩慢且不易查覺的，其中地理環境的改變很容易導致生態環境變遷，對水質也會產生直接或間接的影響。臺北水源特定區為大台北重要供水來源，其水質控管是首要的工作。因此，如何建立集水區內土地利用與流域內水質及生態的關連性知識，實為迫切需要的。
本研究旨在應用景觀生態指數計量方法，評估地景變遷與其對水質及生態之衝擊。研究收集特定區94和101兩年度之SPOT衛星影像，藉由影像分類、變遷偵測與景觀生態軟體，量化出之特定區八樣站之景觀生態指標；再比較七年間土地利用、上下游地景與景觀生態指數變遷之情形。結果顯示北勢溪之坪林、虎寮潭與南勢溪粗坑壩等三個樣區，作物類別都有取代森林與道路類別而擴張之情形；而桶後溪上游以及碧湖區塊變化較小。由各樣站量化出之景觀指數探討特定區上游至下游各類地景變遷情形發現，越趨於下游地段建成區塊群聚增加、森林區塊零碎下降、作物區塊鄰近增大、道路區塊蜿蜒上升而水體區塊有聚合增大等情形。
本研究進一步將各地區地景生態指數，與監測之水質生態指標進行相關性分析，結果顯示，當建成區與道路類別在地景中面積越大、邊緣長度越長，即人類的活動越頻繁時，會對各類水質指標產生負面影響。而農作區塊嵌塊數量增加、密度的提升以及有碎裂與穿孔等情況時，水質生態指標也有變差的趨勢。在草地、林地等森林區塊方面，若區塊面積越大、彼此相鄰且呈帶狀分布，會有類似過濾緩衝帶的功能，對水質有正面影響。綜合分析得知，經由空間與時間上地景指數的比較，能夠推測出該區域景觀分布與變遷情形以及水質變化之趨勢。

關鍵字

景觀指數 ； 土地利用 ； 河川水質 ； 環境生態監測指標

並列摘要

The change of hydrological environment in a watershed due to land use variation is usually slow and imperceptible. Since there are complicated relationships among water quality, water resource and ecosystem, the change of geographical environment will result in a variation of ecological environment and impacts of water quality. The rivers and the Feitsui reservoir at the Taipei water source district is an important source of water supply in Taipei Area. The control and management of water quality is a primary concern in this area. Therefore, it is an urgent need to establish the knowledge in land uses, water quality and ecology in the watershed.
The objective of the study is to use the landscape ecological metrics to assess land use change and associated impacts on water quality and ecology. The SPOT satellite images of 1995 and 2012 were implemented classification, change detection, and the landscape ecology metrics calculation at eight sampling sites in the district. The results showed that the agricultural area has expanded and partially replaced the area of forest and road at the Pinglin, Hu Liao Tan of Peishih River and Cukeng Dam of Nanshih River. The change was less in Bihu and in the upstream of Tungho River. It can also conclude from the study that when it tends to the downstream location in the special district, the cluster of construction zone, the contiguity of agricultural zone, the meander of road zone and the polymerization of water zone increase, but the fractional of forest zone decrease.
This study performed the correlation analysis for landscape metrics of each area and ecological indices of water quality. The result showed that it could bring out negative influences when large area and long length of edge of construction zone and road exist, which is the results of human activities. The trend was getting worse in agricultural blocks when the quantity of patches increased, the density elevated and there were situation such as perforation and fragmentation. There were positive effects in blocks of grass and forest if they were in large area of blocks and adjacent to each other, because they functioned like the buffer strips. It can see from the study that it is capable of evaluating the landscape distribution and the change of water quality in this area by comparing the spatial and temporal variation of landscape metrics.

並列關鍵字

landscape metrics ； land usage ； river water quality ； environmental ecology indices

參考文獻

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