| Abstract: | 在全球的碳固定機制中，熱帶雨林扮演由大氣進入林木相當重要的角色，碳被儲存在泥炭沼澤森林中的樹木與有機土-些許腐爛的植物內，然而森林大火導致碳被排放至大氣層，對生態環境造成破壞性的影響。在Leuser Ecosystem-Aceh地區，聯合國科教文組織指定Leuser森林作為Sumatera熱帶雨林遺產的一部份，存有高度生物多樣性的本地物種。此森林地區持續不斷地發生大規模火災事件，在1990年至2018年期間，Southwest Aceh與Nagan Raya Regency (Tripa泥炭沼澤森林)的泥炭林面積減少至今僅存10.47%，從80,269公頃減少到8,407公頃。因此，為了支持環境保護和環境恢復的理由，評估該地區生態環境與森林大火相關的脆弱性顯得至關重要。
本研究我們提出評估框架，其中包含5個指標（森林火災、水文氣象學、土地資源、地形、社會經濟學），透過16個變量去量化生態環境脆弱度，其中8個變量由1990、1998、2004、2009、2018年的Landsat衛星影像推算獲得。我們使用GIS技術推導生態環境地圖，這些地圖分為6個等級（極低，低，中，中高，高和極高的脆弱度），利用層次分析法（Analytic hierarchy process, AHP）決定全球權重、局部權重以及分類權重。結果表明觀察森林大火在1990-2018年間特別突出的年份之後，高和極高脆弱度的空間分布範圍顯著增加。
由極高脆弱度等級的分布顯示其增長變化在1990年為1%，1998年為12%，2004年為4%，2009年為9.8%，2018年為7.6%。這些地區的特徵是人類活動密度較高，如例如農業活動、砍伐焚燒、興建建築物，以及莽原、疏林。在這些區域由於森林火災以及人類活動的因素，我們對生態環境評估的框架顯得更有價值。生態環境脆弱度的分析圖有助於地方當局為每個脆弱程度規劃有效的解決對策，以恢復生態環境的豐富性和健康。
;The tropical rainforest plays an important role in global carbon sequestration from the atmosphere into forest tree. The carbon is stored in the trees and organic soil-partly decayed plants in the peat swamp forest. The deforestation due to fire disturbance triggers carbon to emit back to the atmosphere, resulting in devastating impacts on the eco-environment. The Leuser Ecosystem-Aceh area, UNESCO designated Leuser forest as a part of the tropical rainforest heritage of Sumatera, contains high biodiversity indigenous species. However, the massive fire events continuously occured across the forest areas. The peat forest areas decreased remain only 10.47%, which are declined from 80,269 ha to 8,407 ha in the time period from 1990 to 2018 in Southwest Aceh and Nagan Raya regency (Tripa peat swamp forest). Thus, it is crucial to assess the vulnerability of the eco-environment in this region in association with forest fire to support for environmental protection and restoration.
Here, we propose an assessment framework consisting of five metrics (forest fire events, hydrometeorology, land resource, topography, and socioeconomics) to qualify the eco-environment vulnerability via 16 variables, with eight of them derived from Landsat images. Landsat images acquired in 1990,1998, 2004, 2009 and 2018. GIS techniques were used to derive the eco-environmental maps, which are classified into six levels (very low, low, medium, medium high, high, and very high vulnerabilities). The Analytic hierarchy process (AHP) is applied to determine the global weights, local weights, and class weights. Results show that spatial distribution of high and very high vulnerable significantly increasing in the time frame of 1990 – 2018 following the high massive forest fire case in highlighted year.
The contribution of very high vulnerability level shows evolving patterns of 1% in 1990, of 12% in 1998, 4% in 2004, 9.8% in 2009, and 7.6% in 2018. These areas are characterized by high density of human activities such as agricultural practices including plantation, slash burning cultivation, built-up, savannah, and sparse forest. Our framework is valuable for eco-environmental assessment due to forest fire and human disturbances in the region. The eco-environmental vulnerability map is useful for local authorities to design effective solution for each vulnerable degree to mitigate and restore the richness and health of eco-environment. |
