Abstract

Exotic weed invasion has been identified as one of the serious environmental problem impacting the structure, composition and function of biological diversity. They are aggressive colonizers, which have flexible habitat requirement and ability to outcompete native species. The present paper describes the distribution and autecology of an exotic weed Limnocharis flava (L.) Buchenau (an emergent aquatic weed of ‘Limnocharitaceae’) in Kumarakom Grama Panchayat, one of the well known tourist spot of South India famous for its vast stretches of paddy fields, wetlands and backwaters. The mapping of L. flava in the entire study area has been done using Geographical Information System (Arc-info 8.3 version). The growth and distribution pattern of L. flava were studied quantitatively. Data on distribution, abundance, biomass, ecological associations and root zone nutrient quality of water and sediment samples were collected from different sampling points of Kumarakom. The study reflected that nutrients, water depth and land use patterns were the major factors responsible for the growth and proliferation of this exotic weed. The strategies for controlling L. flava invasion are discussed in detail. If early steps are not taken to eradicate this weed, it will become a problematic weed in the same way as other noxious aquatic weeds like Salvinia molesta D. Mitch and Eichhornia crassipes (C. Martius) Solms-Laub.

中文摘要

外來雜草的入侵對於生物多樣性的結構、組成以及功能所造成的衝擊，已是全世界公認的重大環境議題之一。這些外來物種多半是具有侵略性的殖民者，對於棲地環境的要求具有彈性，並且有能力競爭排除原生物種。本研究就印度南部克拉拉邦庫瑪蘭肯地區 (Kumarakom Grama Panchayat) 的黃花藺 (Limnocharis flava (L.) Buchenau) 之分布及個體生態學進行探討。庫瑪蘭肯地區是印度南部為人熟知的觀光勝地，向來以其一望無際的稻田及濕地著稱。本研究以地理資訊系統軟體 (Arc-info 8.3 版本) 繪製、量化黃花藺於本地區的分布。此外，並於研究範圍內之採樣點，收集黃花藺之豐富度、生物量、生態相關數值、根部營養鹽、水質及沉積物樣本加以分析研究。結果顯示，營養程度、水深以及土地利用類型為主要造成黃花藺大量繁殖的元兇。本文中也就黃花藺的控制方法加以討論。針對此物種而言，早期的發現與移除最為重要，否則造成的危害，將如人厭槐葉萍 (Salvinia molesta D. Mitch) 及布袋蓮 (Eichhornia crassipes (C. Martius) Solms-Laub)所造成的入侵一般難以收拾。

Keyword: Limnocharis flava (L.) Buchenau, Exotic weed, Invasion, Biological diversity, Sustainable management. 黃花藺、Buchenau、外來雜草、入侵、生物多樣性、Sustainable management。