臺中市生態系服務對水-能源-糧食鏈結永續性的時空演變與影響評估

Abstract

在全球氣候變遷與資源壓力日益嚴峻的背景下，如何在經濟發展與生態保育之間取得平衡，已成為永續發展的重要課題。水、能源與糧食三者之間具高度關聯性，形成所謂的水－能源－糧食鏈結(Water- Energy- Food Nexus, WEF Nexus)。然而，目前對於生態系服務（Ecosystem Services, ESs）與WEF Nexus永續性之間關聯性的探討仍顯不足，尤缺乏區域尺度的實證研究。臺中市作為臺灣主要都市之一，其快速的城市化與產業發展對區域資源與環境系統帶來高度挑戰，因而成為進行相關研究的重要案例區。本研究旨在透過InVEST模式與空間統計方法，量化臺中市2007、2014與2021年間生態系服務之空間分布，並結合WEF Nexus永續性指標，探討兩者間之空間權衡關係與耦合協調度模型。期望藉由本研究，提供臺中市永續資源管理之量化依據，並為整合生態系服務與資源鏈結永續性提出具體策略建議，進一步促進區域永續發展與政策規劃。 本研究以臺中市為研究區，針對2007、2014與2021年三個時間點，運用InVEST模式量化七項生態系服務，包括碳儲存、作物生產、氮、磷營養鹽留存、沉積物留存、都市降溫與產水量，並進行標準化處理後透過區域型局部空間關聯指標 LISA（local indicators of spatial association）進行空間熱點分析，找出穩定且具包含四種以上生態系服務供應功能之熱區。另一方面，依據T. Ding, Fang, Chen, Ji, and Fang (2023)提出之WEF Nexus永續性指標體系，蒐集十八項代表性指標並以熵權法計算其權重，建立水、能源、糧食三個子系統之永續性空間分佈。進一步，採用皮爾遜相關分析探討多項生態系服務與WEF Nexus永續性之間的權衡關係，並運用耦合協調度方法(Coupling Coordination Degree Method, CCDM)評估二者在行政區尺度上的耦合協同程度，揭示其潛在的空間協作與資源優化可能性。 研究結果表示臺中市具有四種以上生態系服務熱點的區域分布於全市36%至38%之間，主要集中於林地覆蓋區，凸顯自然植被對生態功能的貢獻。臺中市整體生態系服務以協同關係為主，惟作物生產、產水量與都市降溫等項目與其他服務間存在競合或不穩定關係，主要受限於降雨與土地利用的時空變異性。WEF Nexus永續性分析方面，東部山區在水與糧食子系統中表現出高度且穩定之永續性，西部都市與農業區則因人口集中與資源需求壓力導致永續性偏低，能源子系統則在工業區域如大雅與西屯展現較佳表現。耦合協調度進一步揭示，和平區因森林覆蓋與自然資源優勢，整體協調度長期穩定表現最佳。碳儲存、營養鹽留存等調節型服務與WEF Nexus永續性關聯高度協同，且整體協調性隨時間提升，反之，都市核心與農業平原地區則多呈現不協調狀態。其中，三個年份各行政區的沉積物留存則持續呈現不協調狀態。作物生產受限於旱作比例與都市化壓力，多數行政區呈現不協調或弱協調，特別是和平區長期高度不協調。Pearson相關分析顯示，水與糧食子系統普遍與碳儲存、都市降溫、沉積物留存等服務具中至高度協同關係，能源子系統則僅與作物生產呈穩定正相關。三大子系統間競合與協同關係具時間動態，都市化與空間資源配置對整體耦合關係具有明顯影響。 本研究透過城市鄉鎮尺度探討生態系服務與水-能源-糧食鏈結永續性之空間與時間變化特性，透過耦合協調分析與權衡關係，揭示不同區域生態功能與資源系統間的互動關係與協同潛力。其研究成果可作為政府在國土規劃與資源管理政策制定之重要參考依據，亦可提供其他城市在推動多元生態系服務與WEF Nexus永續性協調發展時之策略指引，促進永續城市治理與區域整合發展。

Amid escalating global climate change and increasing resource pressures, achieving a balance between economic development and ecological conservation has become a critical issue for sustainable development. The water-energy-food nexus highlights the highly interlinked nature of water, energy, and food systems, which are directly influenced by the supply and stability of multiple ecosystem services. However, current research on the relationship between ecosystem services and the sustainability of the WEF nexus remains insufficient, especially empirical studies at the regional scale. As one of Taiwan’s major cities, Taichung has undergone rapid urbanization and industrial development, which has posed significant challenges to regional resources and environmental systems—making it an ideal case for this type of research. This study aims to apply the InVEST model and spatial statistical methods to quantify the spatial distribution of seven ecosystem services in Taichung City for the years 2007, 2014, and 2021. These services include carbon storage, food production, nitrogen and phosphorus retention, sediment retention, urban cooling, and water yield. After standardization, hotspot analysis was conducted using local indicators of spatial association to identify areas with stable multifunctionality—defined as providing four or more ecosystem services. Meanwhile, based on the WEF nexus sustainability indicator system proposed by T. Ding (2023), eighteen representative indicators were collected and weighted using the entropy weight method to construct spatial distributions of sustainability across the water, energy, and food subsystems. Subsequently, Pearson correlation analysis was used to examine the spatiotemporal trade-offs between various ecosystem services and the WEF nexus sustainability indices. The Coupling Coordination Degree Method was also employed to assess the degree of coordination between the two at the administrative district level, revealing potential areas for spatial collaboration and resource optimization. The results indicate that areas with hotspots of four or more ecosystem services cover approximately 36% to 38% of Taichung’s area, primarily concentrated in forested zones, highlighting the crucial role of natural vegetation in supporting ecological functions. Overall, ecosystem services in Taichung exhibit mainly synergistic relationships, though trade-offs or unstable interactions exist—particularly between crop production, water yield, and urban cooling—largely influenced by spatiotemporal variations in precipitation and land use. In terms of WEF nexus sustainability, the eastern mountainous regions display high and stable performance in the water and food subsystems, whereas the western urban and agricultural zones show relatively lower sustainability due to population density and resource pressure. The energy subsystem performs better in industrial areas such as Daya and Xitun. Coupling coordination analysis further reveals that Heping District, benefiting from its extensive forest cover and abundant natural resources, consistently exhibits the highest and most stable coordination levels. Regulating services such as carbon storage and nutrient retention show strong synergies with WEF sustainability, with overall coordination improving over time. In contrast, urban cores and agricultural plains often display uncoordinated states. Notably, sediment retention remains in an uncoordinated state across all districts throughout the three study years. Crop production, constrained by a high proportion of dryland farming and urbanization pressures, demonstrates uncoordinated or weakly coordinated states in most districts—particularly in Heping District, which shows persistent high-level uncoordination. Pearson correlation analysis indicates that the water and food subsystems generally exhibit moderate to strong synergies with services like carbon storage and urban cooling. In contrast, the energy subsystem shows a stable positive correlation only with crop production. The competitive and synergistic relationships among the three subsystems vary over time, with urbanization and spatial resource allocation having a clear influence on the overall coupling dynamics. By examining the spatial and temporal dynamics of ecosystem services and WEF nexus sustainability at the township level, this study reveals the interactive relationships and coordination potential between regional ecological functions and resource systems through trade-off and coupling analysis. The findings provide a quantitative foundation for sustainable resource management in Taichung and offer strategic insights for integrating ecosystem services and WEF nexus sustainability, thereby promoting sustainable urban governance and regional integrated development.