互花米草在關渡自然保留區的擴散評估與模擬

Abstract

本研究試圖了解外來種互花米草在關渡自然保留區的入侵性，並且模擬互花米草進入關渡自然保留區可能的生長趨勢，提供防治外來種互花米草與經營紅樹林生態的參考依據，為面對或管理外來物種的決策支持提供一種方法。比較互花米草與水筆仔的生物特性、環境的適應力與兩者在關渡自然保留區的環境適合度及競爭關係，本研究結合生態系統模型模擬的兩種方式，利用『系統動力學』 與『行為者基礎模型』，將互花米草與水筆仔在關渡自然保留區的生長關係，由 Tilman多物種共存模型建構出的生態模型，並運用STELLA和NetLogo軟體模擬不同假設與情況下兩物種在時間與空間上的動態變化。 就關渡自然保留區而言，水筆仔對台灣有較高的環境適合度，加上物種本身的高擴散力與成林高密度的競爭優勢，對倘若自然漂流到關渡自然保留區的互花米草具備控制其爆發的條件，而淡水河岸其他水筆仔覆蓋度低的裸露灘地則是互花米草較具備競爭優勢。防治工作的進行，在裸露灘地，需把握互花米草尚未進入快速擴散期之階段的防治工作；而關渡自然保留區最需關注由分散多處進入之互花米草的擴散。進行互花米草與水筆仔移除工作以每年進行一定比例的移除對擴散有較佳的控制效果。

This study attempts to understand the possibility of an alien species (Spartina alterniflora Loisel) outbreak in Kuantu Nature Reserve and to simulate the tendency of diffusion in order to provide basic information for decision making on the management of this alien species, and also to provide a scientific method for management of alien species in the decision-making processes. Biological characteristics and environmental adaptability of Spartina alterniflora Loisel and Kandelia candel (L.) were compared and their competitive relationship was estimated based on the environmental conditions in Kuantu Nature Reserve. Tilman's multispecies coexistence model was used as an ecological model to explore population interactions between Spartina alterniflora Loisel and Kandelia candel (L.) Druce in Kuantu Nature Reserve. Then, two ecosystem simulation models, system dynamics and agent-based models, were applied to evaluate population dynamic changes in these two species by using STELLA and NetLogo software package, respectively. Based on current environmental conditions of Kuantu Nature Reserve, Kandelia candel (L.) forest can limit the spread of Spartina alterniflora Loisel. However, Spartina alterniflora Loisel has great competitive ability in bare area of Tamsui River. For bare area, the prevention and control of Spartina alterniflora Loisel shall take immediate action before its population enters the rapid diffusion period. In Kuantu Nature Reserve, the prevention and control of Spartina alterniflora Loisel need to pay attention on this species diffusing through multiple sites. It will be more effective to annually removal of a certain proportion of this species population in order to be in a better control of Spartina alterniflora Loisel in Kuantu Nature Reserve.