绿狐尾藻区域适应性与生态竞争力研究

绿狐尾藻(Myriophyllum elatinoides)湿地具有高效去除水体中有机物和氮磷的功能,其生物质产量高并可以作为优质畜禽饲料,是实现农业面源污染治理与氮磷污染物资源化利用有机结合的可靠途径,但对其生长适应性和生态竞争力尚缺乏研究。本研究依托我国亚热带(南方)和温带(华北)地区的11个中国科学院野外试验站开展了系列试验。结果表明:绿狐尾藻在中国亚热带地区可以良好生长并顺利越冬,但在中国北方温带地区则不能自然越冬;风浪、水深、蓝藻爆发以及香蒲(Typha orientalis)、莲(Nelumbo nucifera)、双穗雀稗(Paspalum distichum)、辣蓼(Polygonum hydropiper)、水竹叶(Murdannia triquetra)等本土水生植物竞争等多种因素均会对绿狐尾藻的正常生长产生显著抑制作用;绿狐尾藻存在非专一性天敌,主要包括斜纹夜蛾(Spodoptera litura)、造桥虫(Anomis flava)等食叶性昆虫,其主要爆发期在夏季7—8月的高温阶段。因此,从生长适应性、群落竞争力、天敌危害等方面来看,初步认为绿狐尾藻在我国大陆地区大范围自然扩张的可能性十分有限。

Regional adaptability and ecological competitiveness of Myriophyllum elatinoides in mainland China

Myriophyllum elatinoides wetlands can efficiently remove organic substances, such as nitrogen (N), and phosphorus (P), from polluted waters, and the biomass of M. elatinoides can be utilized as a high-quality feed for livestock and poultry as it contains high concentrations of nutrients such as protein. This suggests that M. elatinoides wetlands are reliable areas for combining the re-utilization of N & P pollutants and the control of agricultural non-point source pollution. However, the ecological adaptability and competitiveness of M. elatinoides are still unknown and require evidence-based clarification in China. Therefore, several M. elatinoides plantation experiments were conducted in eleven of the Chinese Academy of Sciences'' field observation stations located in the subtropical and temperate regions of China, from Yucheng County in Shandong (in the north) and Wuxi City in Jiangsu Province (in the east) to Zhongxian County in Chongqing City (in the west). Our results regarding M. elatinoides plantations provided three main conclusions. First, M. elatinoides grew well and overwintered smoothly in subtropical regions. However, it could not overwinter under the natural conditions of the temperate area in Northern China. Second, the natural growth of M. elatinoides could be significantly disturbed by several factors, such as large waves, deep water, algae (cyanobacteria) blooms, and competition for survival with other native aquatic plants, such as Typha orientalis, Nelumbo nucifera, Paspalum distichum, Polygonum hydropiper, and Murdannia triquetra. Third, non-specific predators to M. elatinoides, especially the leaf-feeding insects Spodoptera litura and Anomis flava, were observed in all study regions and caused severe damage to M. elatinoides biomass,which mainly occurred in the hot season from July to August. Therefore, from several aspects of its ecological adaptability, natural competitiveness, and pest damage, we could conclude that the natural extension risk of M. elatinoides at an aggressive scale in mainland China is very low and highly manageable.