氣候與土地利用與覆蓋變遷對生態系服務的影響-以大屯溪流域為例

Abstract

氣候變遷隨著時間的推移，影響著土地利用與覆蓋變遷，進而深深影響生態系服務。為了實現生態系永續健康發展，如何對土地利用與覆蓋變遷和氣候變遷的影響做出量化評估，並通過永續土地保育計劃對生態系服務進行維護是研究重點。 本研究中以臺北市大屯溪流域為例，參考IPCC第五次評估報告（AR5）中五個情境預測的2022年之氣候數據，採用CLUE-s模式（Conversion of Land Use and its Effect at Small regional extent）模擬不同土地管理方案及氣候變遷影響下2022年土地利用與覆蓋的變遷情況，藉由生態系服務評估與權衡模式InVEST模式(Integrated Valuation of Ecosystem Services and Tradeoffs)模擬研究區域內2022年之陸域生態系服務（棲地品質、碳貯存量）及水域生態系服務（出水量、沉積物留存、氮營養鹽留存量和磷營養鹽留存量）分佈情況，通過與1994年的生態系服務進行kappa對比，分析適合實施的土地利用與覆蓋保育規劃方案,從而得出最佳土地利用與覆蓋保育規劃方案以達到生態維護之目的。 研究中將氣候（溫度與雨量）作為新增的動態CLUE-s模式考量因素，與前人結果進行對比，發現其AUC值與KAPPA值皆得到提升，表明氣候對於土地利用與覆蓋變遷是有影響的。InVEST模式模擬結果表明，氣候變遷對水域生態系服務（出水量、沉積物留存）影響較大。 本研究中土地管理方案的情境1單以陽明山森林公園作為保育區域，是目前政府採取的保育政策，作為對照組。採用模擬1994年生態系服務的熱點，代入Zonation空間分佈統計得到的前（10%，20%，30%）重點區域聯合陽明山國家森林公園做為土地管理方案的情境2、3、4。土地管理方案的情境5則不做任何限制區域。代入Zonation空間分佈統計得到的前（10%，20%，30%）重點區域作為土地管理方案的情境6,7,8。 研究發現，土地利用與覆蓋變遷對生態系服務有影響，其中保育大部分陽明山森林公園的情境（情境1、2、3、4、8）在陸域生態系服務（棲地品質、碳貯存量）效果較優。保育了Zonation空間分佈的情境（情境2、3、4、6、7、8）在水域生態系服務（氮營養鹽留存量和磷營養鹽留存量）效果較優。水域生態系服務（出水量、沉積物留存）所有保育情境結果接近，但是不同氣候變遷模式下有差異，證明保育水域生態系服務（出水量、沉積物留存）應當注重氣象的調整。考量到生態系服務效果與經濟因素，認為情境2（Zonation前10%重點區域加陽明山森林公園）是最佳情境。由此認為現階段對於陽明山森林公園的保育是合理的，但是基於保育水域生態系服務（氮營養鹽留存量和磷營養鹽留存量）的考慮建議將Zonation前10%重點區域作為後續政策規劃的參考。

Climate and land use change has influenced the ecosystem and biodiversity on various levels, having an effect on human beings. So it is meaningful and important to identify the impact from Climate and land use change, and then to formulate sustainability land use management strategies to maintain ecosystem. Take Datun river watershed which is located in the northern part of Taiwan as an example. We used CLUE-s model to simulate the future land use map under different strategies and different future climate scenarios of RCP2.6 and RCP8.5 which are all from the research of the IPCC fifth assessment report (AR5). Meanwhile, the research put the result of CLUE-s into InVEST model to simulate the future ecosystem services, including the terrestrial ecosystem services (Biodiversity, Carbon storage) and freshwater ecosystem services (Water yield, Sediment retention, Nutrient retention). Finally, comparing the 1994’s ecosystem service, to confirm the best land use management strategy on ecosystem protection. As a result，we found that climate is an important factor in land use change caused the AUC and KAPPA in considering climate when using CLUE-s model to simulate land use for higher value than without considering climate. What’s more, beside the result of INVEST, we found that the freshwater ecosystem services (Water yield, Sediment retention) will be affected by climate change, especially the CCSM4 climate scenario. In this paper, we use 1994’s ecosystem service data to identify the conservation priority of a certain region by LISA and Zonation meta-algorithm, and then to set up different land use restrict areas that serving as land use management strategies. We selected Yangming mountain National Park as protection area as control group. Then named strategy1 for present portaction, strategy 5 for no any restricted area, strategy 6, 7 and 8 (joint set of Yangming mountain National Park as strategy 2, 3 and 4) for the 10% ,20% ,30% Zonation critical protection area. As a result, we found that ecosystem service will be significantly affected by land use change. Compared with 1994’s ecosystem service ,by the Kappa statistical method, Protecting Yangming mountain National Park is important of the terrestrial ecosystem services (Biodiversity, Carbon storage), protecting Zonation critical protection area is important of the freshwater ecosystem services (Water yield, Sediment retention, Nutrient retention), and protecting climate is important of the freshwater ecosystem services (Water yield, Sediment retention). We further prioritized the important conservation areas by strategy 2 in the future but we also found that strategy 1 which is the present conservation is reasonable, based on the conservation of nutrient will consider recommending Zonation of the top 10% key areas for the follow-up policy planning reference.