中国辽宁-浙江沿海地区川蔓草分布现状、生态特征及其主要威胁

Distribution,ecological features,and threats to Ruppia popula-tions between Liaoning and Zhejiang,China

川蔓草(Ruppia)是一种广泛分布在咸水、半咸水生境中的广义海草,其形成的川蔓草床具有重要的生态学价值。然而,对于其在中国境内的分布情况尚缺乏大范围的调查。基于此,本研究于2016—2019年对中国辽宁-浙江沿海区域的川蔓草分布情况进行了初步调查,探究了调查区域内川蔓草的生境分布类型,及生态特征,分析了川蔓草床的主要威胁,并提出了对川蔓草床科学管理的建议。结果表明:川蔓草在中国浙江省、江苏省、山东省、天津市、河北省、辽宁省均有分布;分布面积超过2 100 ha;该区域内分布的川蔓草物种均为中国川蔓草,主要分布生境包括咸水养殖池塘、咸水沟渠(池塘)、盐场、瀉湖(湖泊)、潮间带(围堰)5类;人类活动影响(人工清捞、施药、河道工程等)与极端气候事件(极端干旱事件)都会导致川蔓草床退化,但大部分川蔓草床可以依靠沉积物中的种子库在环境适宜时进行种群恢复;不同生境中的川蔓草种群特征差异较大,因此,对不同生境中的川蔓草应制定差异性管理措施。

Ruppia is a seagrass species that is widely distributed in salt and brackish water habitats.Although Ruppia beds have ecological value,limited information is available on their current distribution in China.Therefore,we investigated the distribution status of Ruppia from northern Zhejiang Province to Liaoning Province during 2016–2019.The habitat types and ecological features of the Ruppia populations were recorded during the investi-gation,and their major threats and suggestions for management were addressed.The results showed that Ruppia was observed in six provinces,including Zhejiang,Jiangsu,Shandong,Tianjin,Hebei,and Liaoning,with a distri-bution area of more than 2,100 ha,and all species were identified as Ruppia sinensis.Five main habitat types were summarized in the investigated area,including marine culture pond,brackish water ditch(pond),saltpan,lagoon(lake),and intertidal zone(batardeau).Human activities(artificial clear,herbicide application,and river engineering)and climate change(extreme drought conditions)could result in a decline in the Ruppia population;however,sev-eral Ruppia populations rely on their seed banks when the conditions become suitable.Moreover,different man-agement strategies should be applied to Ruppia populations in different habitats.