海河流域河流滨岸带入侵植物等级与分布特征

为了解海河流域河流生态系统的退化程度,进而为河流植被修复提供支撑,对河流滨岸带植被入侵物种开展调查,并分析其入侵等级、分布规律及成因. 调查了海河流域九大水系滨岸带402个样地的植物物种信息和主要环境因子,参照《中国入侵植物名录》确定入侵植物名单,根据物种的出现频率和以该物种为优势种的样地所占比例来评价植物入侵等级,并分析物种入侵与环境因子之间的关系. 结果表明:①海河流域河流滨岸带入侵植物共有48种,其中一年生草本植物占72.9%,并且以菊科、苋科、禾本科物种数最多. ②Ⅰ级入侵种为反枝苋(Amaranthus retroflexusn)、苘麻(Abutilon theophrasti)、小藜(Chenopodium serotinum)、鬼针草(Bidens pilosa)和鳢肠(Eclipta prostrata)共5个物种,出现频率超过25%；Ⅱ级入侵种为小蓬草(Conyza canadensis)、大狼杷草(Bidens frondosa)、圆叶牵牛(Pharbitis purpurea)等共11种；Ⅲ级入侵种共32种. ③各水系平均出现入侵植物23种,其中子牙河水系入侵植物种数最多,为33种；其次为滦河水系,为25种；漳卫河水系最少,为15种. ④海拔和堤外土地类型与植物入侵强度相关性最大,海拔与入侵植物的关系主要通过人口压力相关联. 

Grading and Distribution Patterns of Invasive Plants in Riparian Area of Hai Basin

Investigating distribution patterns of invasive plants in riparian areas and evaluating their invasive grades are greatly useful to understand the degree of degradation of river ecosystems. The riparian vegetation from 402 sampling sites in nine river systems of Hai Basin was investigated. Invasive species were confirmed according to the Checklist of Chinese Invasive Plants. Invasive grades were evaluated via the species appearance frequency and the percentage of sites where the species were dominant. The relationship between plant invasion and environmental factors was analyzed as well. The results show that 48 invasive species were registered, of which 72.9% are annual plants. Asteraceae, Amaranthaceae and Gramineae were the families with most invasive species. Amaranthus retroflexusn, Abutilon theophrasti, Chenopodium serotinum and Eclipta prostrata were classified as the invasion grade Ⅰ, appearing in more than 25% of sampling sites. 10 species including Bidens pilosa, Bidens frondosa, Conyza canadensis and Pharbitis purpurea, were classified into gradeⅡ, and 32 as grade Ⅲ. The average number of invasive species in each river system was 23. Ziya River system had the highest number at 33 species, while Zhangwei River system had the least at 15 species. The altitude and land use type outside dykes were the two major factors affecting the species distribution, and also indirectly reflecting the pressure from populations.