自然解方於荷蘭海岸沙丘應用之評析與台灣本土適用之課題

Evaluation of Nature-based Solutions Application in Dutch Coastal Dunes and Lessons Learned for Local Adaptation in Taiwan

全球海岸環境因人為活動和自然變遷的壓力而逐漸惡化，土地利用變遷、海岸侵蝕、海水面上升、污染等等因素，都使這些退化的環境變得相對脆弱，也提高了災難發生的風險。在面對這些挑戰的各種對策中，「自然解方」因為它的高度適用性及諸多好處而受到全球越來越多的關注。海岸沙丘是海岸防護的天然屏障，在思考對應海水面上升及海岸侵蝕的挑戰時，常比傳統的硬性工程措施，更加適合應用「自然解方」來減輕災害風險。本研究評析幾個在荷蘭海岸沙丘應用「自然解方」的實作案例，收集其相關的環境管理策略，討論其過程與成效，並將這些經驗教訓提供臺灣海岸本土適用之參考。雖然荷蘭海岸線在過去大部分已受到沙丘與不同軟性工法的保護，現今則更重視與自然協作。在這些應用「自然解方」的專案計畫中，減少人為的介入，明顯地促進了生物多樣性的發展，也加快了環境的恢復。臺灣和荷蘭一樣，相當倚賴海洋資源，海岸環境的多樣性高，並擁有許多獨特的棲地環境，但海岸地區同樣也面臨許多如海岸侵蝕的威脅。過去針對海岸侵蝕的對應策略以硬性工法為主，較少從生態面向來思考，而海岸管理也因事權分散而導致缺乏綜合管理，所以臺灣迄今尚無任何地區以自然生態系統管理面向，來研究軟性工法或探究如何降低災害風險。但以2020年6月新成立的桃園草漯沙丘地質公園為例，可以發現人們對於以設置地質公園方式來保育沙丘、降低災害風險，或透過可持續管理來加強沙丘生態系統等作為，已愈感興趣。現在這個地方級地質公園仍保存著脆弱的沙丘環境和大約八公里的活動海岸線，應該是一個可以適用「自然解方」的地區。

Coastal environments are deteriorating worldwide due to a combination of human activities and natural stressors, such as land-use change, coastal erosion, sea level rise, pollution, etc. These degraded environments are vulnerable and can become a driver for disaster risk. As a countermeasure to these challenges, Nature-based Solutions (NbS) gain more awareness on a global scale due to their high applicability and many co-benefits. Additionally, NbS have a high rate of long-term benefits compared to traditional (hard) adaptation measures, which have been used frequently as a solution to sea level rise and coastal erosion. Coastal sand dune environments are well suited areas to implement NbS because they already act as a barrier to sea level rise or coastal erosion. Building upon this knowledge, it is important to compare coastal dune sites among different localities and learn from best practices. This study will contribute to gaining more knowledge on NbS and management strategies in sand dune areas in the Netherlands and provide lessons learned for Taiwan. For a large part, the Dutch coastline is protected by sand dunes, and different soft engineering approaches have been established over time, recently focussing more on working with nature. During the implementation of these projects, it became evident that less human involvement stimulates biodiversity and speeds up environmental recovery. Like the Netherlands, Taiwan also relies on marine sources and has a high diversity of coastal environments with unique habitats, but the coastal zone also faces many threats. Strategies to deal with coastal erosion are more focused on hard engineering methods and fragmentation in sectoral management represents different interests, leading to lack of integrated management in Taiwan. So far, not many areas in Taiwan are studied in terms of soft engineering approaches or disaster risk reduction through natural ecosystem management. This paper will outline different management approaches and experiments that are conducted in Dutch dune areas, discuss the evaluation of these projects, and explore possible implications for Taiwan. More specifically, there is a growing global interest in the use of geoparks for disaster risk reduction through NbS, by conservation or enhancement of ecosystems through sustainable management. A new geopark in Taiwan, called Caota Sand Dunes, now conserves a fragile dune environment and 8 km of living shoreline and might be a well-suited area to implement NbS strategies.