濕地植物保育新思維：由貢寮水梯田的植物多樣性談其保育價值的生態學基礎

Plant Diversity of Gongliao Rice Terrace and Ecological Basis of its Conservation Value

謝佳倫(Chia-Lun Hsieh) ； 方韻如(Yun-Ju Fang) ； 謝傳鎧(Chuan-Kai Hsieh) ； 鍾國芳(Kuo-Fang Chung)

《國立臺灣大學生物資源暨農學院實驗林研究報告》 29卷4期 (2015/12) Pp. 279-291

https://doi.org/10.6542/EFNTU.2015.29(4).5

摘要

低海拔地區為人類活動最頻繁的區域，其自然棲地也因長期人為干擾而遭到嚴重破壞，其中天然濕地等水生植物的生存環境更是長期被忽略且破壞最為嚴重的棲地，致使許多低海拔水生植物嚴重瀕危。但相較於「天然」濕地，位處新北市貢寮山區的水梯田除了有豐富的極高的水生植物多樣性，也意外成為許多臺灣低海拔極為罕見的動、植物，包括許多現已瀕危的水生植物，最後殘存的棲地之一。何以「人造」的水梯田提供了低海拔水生植物的重要棲地，並孕育了豐富的生物多樣性？此一看似矛盾的現象在生態學上是否有適切的解釋？在生態學文獻中常以中度干擾假說（Intermediate Disturbance Hypothesis, IDH）來解釋人造干擾棲地高生物多樣性的現象，而本研究根據貢寮農民之傳統農作法及水梯田植物調查之結果提出貢寮水梯田符合Nekola（1999）在Ecology（80: 2459-2473）期刊上發表之「生物避難所（biological refugia）」的定義，即在低海拔「天然」濕地等水生植物原本棲息的環境消失後，貢寮地區「人造」的水梯田提供了水生植物殘留的生存空間；而更精確地來說，貢寮水梯田是晚近「新」形成的人造棲地，在原有天然溼地快速消失的近代，接納了原本傳播能力即佳的水生植物而成為生物多樣性高的水生植物避難所，因此貢寮水梯田可視為臺灣北部低海拔水生植物的「新避難所（neorefugia）」。本研究突顯貢寮水梯田與其創造出的里山價值對於水生植物與低海拔生態保育的重要性，在低海拔濕地植物棲地大量消失的當下具有相當重要的意義，應為保育主管機關重視。

關鍵字

生物避難所 ； 湧泉溼地 ； 新避難所 ； 中度干擾假說 ； 水生植物 ； 濕地保育 ； 人造棲地 ； 里山倡議 ； 生態系服務功能

並列摘要

Human activities mostly concentrate in low elevation. Consequently, lowland natural habitats have been disturbed and destructed at a higher rate. Of the various lowland natural habitats, wetlands and other environments alike suitable for aquatic plants are amongst the most neglected and least protected, which resulted in rapid diminishing and/or extinction of many aquatic plant species worldwide. However compared to natural wetlands, rice terraces in Gongliao, New Taipei City, constructed over generations by local farmers, are an artificial habitat harboring surprisingly high species biodiversity, offering remaining and even last sanctuary for a number of rare and highly endangered animal and aquatic plant species. How could these artificially constructed rice terraces become important habitats for lowland aquatic plants and harbor rich biodiversity? Are there ecological theories supporting this seemly paradoxical phenomenon? In literatures, ecologists often explain high species diversity in artificially constructed habitats such as Gongliao rice terraces by the Intermediate Disturbance Hypothesis (IDH). Alternatively, we propose that Gongliao rice terraces are biological refugia, offering ＂habitats that support populations not able to liveelsewhere in a landscape＂ [Nekola (1999) Ecology 80:2459-2473]. Essentially, rice terraces are artificial habitats recently constructed compared to surrounding natural wetlands, and serve as newly formed habitats for aquatic plants, especially those with superb dispersability. As such, Gongliao rice terraces qualify as neorefugia for lowland wetland plants in northern Taiwan, ＂representing habitats that are younger than the surrounding biological matrix.＂ Together with traditional and organic farming practices in the area, recognition of Gongliao rice terrace as important biological neorefugia not only emphasizes its importance for conservation of lowland aquatic plants, but also highlights its cultural values emerging from the Satoyama Initiative. We argue that, with rapid diminishing and destruction of lowland natural habitats in Taiwan, conservation values of lowland rice terraces such as those in Gongliao should be officially emphasized, recognized and sustained.

並列關鍵字

aquatic plants ； artificial habitat ； biological refugia ； ecosystem service ； fens ； intermediate disturbance hypothesis (IDH) ； neorefugia ； Satoyama Initiative ； wetland conservation