气候变化下喜旱莲子草在海南热带雨林国家公园的扩散风险研究

Dispersal risk of Alternanthera philoxeroides in Hainan Tropical Rainforest National Park under climate change

关键词:  Biomod2模型, 外来入侵植物, 潜在分布, 环境因子, 国家公园

Key words:  Biomod2 model, alien invasive plants, potential distribution, environmental factors, national park

摘要:

喜旱莲子草(Alternanthera philoxeroides)在全球范围内广泛入侵,给当地生态环境带来严重威胁。海南热带雨林国家公园作为生物多样性保护的关键区域,正面临着喜旱莲子草扩散传播的风险,因此准确掌握其分布情况并开展动态监测至关重要。该研究通过野外实地调查收集数据,采用R语言的“biomod2”程序包建立物种分布模型,分析喜旱莲子草在海南热带雨林国家公园当前及未来气候模式下的空间分布及关键环境影响因素。结果表明:(1)喜旱莲子草在海南热带雨林国家公园的适生区分为低度、中度、高度和非常适宜适生区,当前时期的高适生区面积约为180.75 km²,主要集中于鹦哥岭、吊罗山及黎母山片区。(2)参与模型预测的各类因子中,气候因子对喜旱莲子草生境适宜性的影响最为显著。在11个环境变量中,年均温变化范围(bio7)、植被归一化指数(ndvi)、最暖月最高温度(bio5)和最暖季度降水量(bio18)是影响喜旱莲子草生境适宜性的关键环境因子。(3)在未来不同气候情景预测下,喜旱莲子草总适生区变化趋势呈现出两种不同态势,但质心变化均呈现东移趋势。与温和可持续发展情景(SSP126)相比,在高排放、极端气候加剧情景(SSP585)下,喜旱莲子草的适生区扩张更为迅速。综上认为,当前气候下喜旱莲子草的潜在适生区域主要集中在国家公园的边界区域; 未来全球极端气候增多及环境剧烈变动将增加其在国家公园内的扩散风险。因此,持续开展喜旱莲子草的动态监测,掌握其入侵和扩散态势,是有效管理并预防喜旱莲子草在国家公园大面积扩散的重要举措。

Abstract:

Alternanthera philoxeroides, a globally invasive species, poses a significant threat to local ecological enviroment due to its rapid spread and adaptability to diverse environmental conditions. Hainan Tropical Rainforest National Park, a critical area for biodiversity conservation, is increasingly at risk from the spread of A. philoxeroides. Therefore, accurately mapping its distribution and conducting dynamic monitoring are essential for effective management. This study utilized field survey data and employed the “biomod2” package in the R programming language to establish species distribution models, analyzed the spatial distribution of A. philoxeroides in the national park under current and future climate scenarios, as well as key environmental factors influencing its habitat suitability. The results were as follows:(1)The suitable areas for A. philoxeroides in the national park were categorized into low, moderate, high, and very high suitability zones. Under current condition, the highly suitable area covered approximately 180.75 km², concentrated primarily in the Yinggeling, Diaoluoshan, and Limushan areas.(2)Among the various factors influencing habitat suitability, climatic variables were found to have the most significant impact on the distribution of A. philoxeroides. Specifically, annual mean temperature range(bio7), normalized difference vegetation index(ndvi), maximum temperature in the warmest month(bio5), and precipitation of the warmest quarter(bio18)were identified as the key factors influencing habitat suitability.(3)The trends in the total habitat suitability area of A. philoxeroides under different future climate scenarios revealed two distinct patterns. In both scenarios, the centroid of suitable habitat shifted eastward. Under the high emission, extreme climate intensification scenario(SSP585), the expansion of suitable habitat was more rapid compared to the moderate sustainable development scenario(SSP126). In conclusion, the potential suitable habitat of A. philoxeroides under current climate condition is primarily located on the periphery of the national park; however, with the expected increase in global extreme climates and drastic environmental changes in the future, the risk of its spread within the national park is significantly heightened. Therefore, continuous dynamic monitoring of A. philoxeroides to track its invasion and spread trends is an important measure to effectively manage and prevent its large-scale spread in the national park.