西沙群岛的有害植物及其防控策略

Pernicious plants in the Xisha Islands and their control strategies

关键词:  有害植物, 入侵植物, 西沙群岛, 热带珊瑚岛, 控制策略, 风险评估

Key words:  pernicious plants, invasive plants, the Xisha Islands, tropical coral islands, control strategy, risk assessment

摘要:

西沙群岛是我国南海西北部的一群热带珊瑚岛屿,其自然环境独特且恶劣、生物多样性较低、生态系统极为脆弱。有害植物是西沙群岛植被退化的重要因素之一。为了开展西沙群岛有害植物的种类、分布及危害程度的调查研究,该文对西沙群岛有植被分布的24个岛屿进行了野外实地调查,并结合相关文献资料及评价体系,对西沙群岛有害植物的种类组成、分布、生长特性和危害程度等进行了全面的调查分析。结果表明:(1)西沙群岛现存有害植物共10科20属26种,其中菊科、豆科、马鞭草科、樟科4个科的植物种类数量占有害植物总数的53.8%。(2)根据生长、分布及危害程度情况,将西沙群岛的有害植物分为3个危害等级,其中1级危害植物有无根藤、飞机草、孪花蟛蜞菊、银合欢、鬼针草、羽芒菊6种,主要分布在永兴岛、东岛、琛航岛和珊瑚岛。(3)有害植物严重程度与岛屿上的植物种数和岛屿面积密切相关。因此,建议对西沙群岛的有害植物进行长期监测,对已造成严重危害的有害植物制定科学的防控策略,包括加强检验检疫、物理清除、化学防治、替代防控和宣传教育等。该研究结果为西沙群岛植被和生态系统的保护、恢复和管理提供了重要基础资料,为我国热带珊瑚岛礁陆域生态系统健康、安全及可持续发展提供了科技支撑。

Abstract:

The Xisha Islands are a group of tropical coral islands in the northwest of the South China Sea. In these islands, the natural environment is unique and harsh, the biodiversity is low, and the ecosystem is extremely fragile. Threat from pernicious plants is one of the important factors for vegetation degradation in the Xisha Islands. It is necessary to investigate the pernicious plant species and their distribution, and the extent of harm in the Xisha Islands. In this research, field investigation on the 24 islands with vegetation in the Xisha Islands was conducted, and the species composition, distribution, growth characteristics and hazard degree of pernicious plants were comprehensively investigated and analyzed in combination with relevant literature and evaluation system. The results were as follows:(1)There were 26 species of pernicious plants belonging to 20 genera and 10 families in the Xisha Islands, of which the number of plant species belonging to four families of Asteraceae, Fabaceae, Verbenaceae and Lauraceae, accounted for 53.8% of the total number species of pernicious plants.(2)According to their growth, distribution, and hazard degree, pernicious plants could be classified into three hazard levels. The Level 1 of pernicious plants included Cassytha filiformis, Chromolaena odorata, Wollastonia biflora, Leucaena leucocephala, Bidens pilosa and Tridax procumbens, mainly distributed in Yongxing Dao, Dong Dao, Chenhang Dao, and Shanhu Dao.(3)The severity of pernicious plants was closely related to the total number of plant species and area of the island. The life form of pernicious plants in the Xisha Islands was mainly terrestrial herbs, accounting for 57.7%. The pernicious plants mainly came from the Americas, with a similar proportion of natural spread, unintentional introduction, intentional introduction sources. Based on the above results, it is suggested to conduct long-term monitoring of pernicious plants in the Xisha Islands, and formulate scientific prevention and control strategies for pernicious plants that have caused serious harm, including strengthening inspection and quarantine, physical removal, chemical control, alternative control, and publicity and education, etc. The research results provide important basic data, scientific and technological support for the protection, health and sustainable development of the vegetation and ecosystems in the Xisha Islands.