摘要
盐沼湿地植物种群动态通常受生物和非生物因素调控。以往研究主要关注盐度、水分等上行因子对滨海湿地植物种群动态的影响。有关动物植食等下行因子的研究相对较少;特别是,植食性动物对滨海湿地植物种群动态影响的空间变异及机制仍不明确。以黄河三角洲盐沼湿地为研究系统,通过开展2年的野外去除实验,研究了天津厚蟹(Helice tientsinensis)植食对芦苇(Phragmites australis)种群动态的下行控制作用及其空间变异。研究结果表明:(1)蟹类强烈抑制芦苇的密度增长(P<0.05),但其抑制强度在3个不同盐沼湿地间存在显著差异;(2)与土壤盐度相比,蟹类对芦苇密度增长的抑制作用较弱;蟹类和盐度对芦苇密度增长的抑制作用均受土壤水分的调节,分别与土壤水分呈正相关和负相关。因此,蟹类植食作用是影响黄河三角洲盐沼湿地芦苇种群动态的关键因素,其作用强度随土壤水分的增加而增强。研究结果有助于深入理解动物植食等下行因子的作用及变异机制,对提升滨海湿地植被保护修复的成效亦有借鉴意义。
Dynamics of salt marsh plants are regulated by biotic and abiotic factors.While effects of bottom-up forces,such as salinity and flooding have traditionally been the research focus in coastal wetlands,top-down effects of herbivores and their spatial-temporal variation remain to be further studied.Here,by employing a two-year crab exclusion experiment,we aimed to investigate the top-down effects of herbivorous crabs(Helice tientsinensis)on the population dynamics of a native grass(Phragmites australis)and how the effects varied spatially among different salt marshes in the Yellow River Delta,China.Our results showed that(1)herbivorous crabs significantly suppressed the density of P.australis(P<0.05),but the strength of their effect varied among different salt marsh sites;(2)compared to soil salinity,the suppressive effects of crabs were weaker,but both factors were mediated by soil water content,and the effects of soil salinity and crabs were mediated by soil water content in opposite ways(negative vs.positive).We conclude that herbivorous crabs are a key top-down factor affecting P.australis population dynamics in the Yellow River Delta salt marshes and that their effects are enhanced with soil moisture.Our results are helpful to understand the top-down effects of herbivory,and can be used for reference to improve the effectiveness of coastal wetland vegetation protection and restoration.
作者
徐长林
任君临
贺强
XU Changlin;REN Junlin;HE Qiang(Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering,Fudan University,Shanghai 200438,China;National Observations and Research Station for Wetland Ecosystem of the Yangtze Estuary,Fudan University,Shanghai 200438,China)
出处
《复旦学报（自然科学版）》
CAS
CSCD
北大核心
2022年第4期417-423,共7页
Journal of Fudan University：Natural Science
基金
国家青年海外高层次人才引进计划
上海市科技人才计划(19QA1401200)。
关键词
盐沼
下行效应
动植物互作
天津厚蟹
芦苇
salt marsh
top-down control
plant-herbivore interactions
Helice tientsinensis
Phragmites australis
