物种多样性及环境因子对入侵植物空心莲子草群落稳定性的影响

为探讨外来入侵植物空心莲子草群落稳定性的驱动机制,在中国21°N-37°N范围内设置73个面积为10 mX 10 m的空心莲子草群落样地(陆生39个,水生34个),分别计算其Godron群落稳定性坐标值和4个α-物种多样性指数,并测定各样地的7项环境因子(经度、纬度、海拔、铵态氮、硝态氮、年均温和年均降雨量),采用回归...

Effects of species diversity and environmental factors on the stability of the invasive Alternanthera philoxeroides communities

To explore the mechanism underlying community stability of the invasive plant Alternanthera philoxeroides,we set up 73 plots(39 terrestrial and 34 aquatic)with a size of 10 m×10 m each in the latitudinal gradient from 21°N to 37°N in China.We calculated the Godron community stability coordinates and fourα-species diversity indices,and measured seven environmental factors(longitude,latitude,elevation,NH₄⁺-N,NO₃^--N,mean annual temperature,and mean annual precipitation).We used regression analysis and redundancy analysis to examine the effects of species diversity and heterogeneous habitats on the stability of invaded communities.The results showed that:(1)A total of 169 plant species were recorded in the terrestrial communities,belonging to 55 families and 147 genera,and the dominant species accompanying A.philoxeroides were Digitaria Sanguinalis,Echinochloa crusgalli,Bidens pilosa and Eleusine indica.A total of 107 plant species were recorded in the aquatic communities,belonging to 49 families and 92 genera,and the dominant accompanying species were Paspalum bipinnata,Ceratopteris thalictroides,E.crusgalli and Bidens pilosa.(2)Results of regression analysis showed that the stability of terrestrial communities decreased with the increases of Simpson diversity index,Shannon diversity index,and Pielou evenness index,whereas the stability of aquatic communities decreased with the increases of Pielou index.There was a unimodal change with the increases of Patrick richness index.(3)Results of regression analysis and redundancy analysis showed that the dominant environmental factors determining the stability of A.philoxeroides community in terrestrial and aquatic habitats were longitude,latitude,mean annual temperature,and mean annual precipitation.Among them,terrestrial community stability increased with the increases of longitude and latitude,but decreased with the increases of mean annual temperature and mean annual precipitation.However,the change of aquatic community stability along the environmental gradient was opposite to that of terrestrial communities.These results indicated that the responses of A.philoxeroides community stability to species diversity and heterogeneous environments differ greatly between terrestrial and aquatic habitats.Under the rapid global environmental changes,more attentions should be paid to the monitoring of terrestrial A.philoxeroides community dynamics in high latitudes as well as aquatic A.philoxeroides community in heavy rainfall areas.