围垦对条子泥互花米草种群年季扩张特征的影响

Effect of reclamation on the annual and seasonal characteristics of Spartina alterniflora population in Tiaozini coastal wetland

为了解围垦对入侵植物互花米草种群扩张的影响,借助无人机航测技术,观测了2017年5月—2018年7月江苏盐城滨海湿地条子泥围垦大堤内外互花米草种群面积的年季变化,并结合实地监测数据,分析了土壤含水率、土壤盐度、生长地高程、地表水位对互花米草生长和种群面积的影响。结果表明:围垦显著降低了互花米草的扩张速度,观测期间堤内面积增幅为21%,而未围垦的堤外增幅超过400%,且互花米草扩张具有明显的季节性,堤内和堤外快速扩张的季节分别为秋季和夏季;围垦区土壤含水率和盐度分别较围垦区外平均降低25%和50%;互花米草植株高度与生长地高程之间存在显著正相关性(P<0.01);互花米草种群的扩张距离与地表水位呈显著正相关性(P<0.01)。研究表明,围垦工程阻断了互花米草海水传播的途径,改变了围垦区土壤水盐条件,进而抑制了互花米草的扩张。

In order to explore the impact of reclamation on the expansion of Spartina alterniflora(a kind of invasive species)population, the annual and seasonal changes of Spartina alterniflora population distributed inside and outside the embankment was observed in the Yancheng coastal wetland, Jiangsu Province from May 2017 to July 2018 with the help of unmanned aerial vehicle(UAV)monitoring tech-nology. Combined with field monitoring data, the effects of soil moisture content, soil salinity, growth elevation, and surface water level on the growth and population area of Spartina alterniflora were analyzed. The results showed that the reclamation significantly reduced the ex-pansion rate of Spartina alterniflora, and the area inside the embankment increased by 21% during the observation period, while the area outside the embankment increased by more than 400%. The population expansion inside and outside the embankment of Spartina alterniflo-ra had obvious seasonality, and the seasons of expansion were autumn and summer respectively. The soil moisture content and salinity in the reclamation area decreased by 25% and 50% respectively compared with the area outside the embankment. There was a significant pos-itive correlation between the height of Spartina alterniflora and the elevation of the growing area(P<0.01). The expansion distance of Spar-tina alterniflora population was significantly positively correlated with surface water level(P<0.01). The reclamation project blocked the transmission path of Spartina alterniflora, and seawater changed the soil water and salt conditions in the reclamation area, and thus inhibit-ed the expansion of Spartina alterniflora.