Effects of the biotic and abiotic factors on the overall invasion
extent of exotic aquatic plants
Regression models showed that the site-level mean biomass of exotic
plants (MBSE ) decreased with increased native
plant richness (Rnative_site , P <
0.001), native plant performance (Pnative_site ,
P < 0.001), and habitat size (Ahabitat ,
P < 0.05), but increased as water nutrient status
(Nwater , P < 0.001) and mean water
depth (Hsite , P < 0.05) increased (Fig.
2A-E). The best-fit SEM showed that Pnative_site had a direct effect on MBSE , butHsite and Ahabitat had
indirect effects by influencing Rnative_site positively or negatively; Rnative_site andNwater not only had direct effects onMBSE , but also had indirect effects by positively
influencing the Pnative_site or negatively
influencing the Rnative_site andPnative_site (Fig. 4A). In addition, although
there were no significant relationships between theMBSE and annual mean temperature (T , P
> 0.05) and distance to town
(Lsite-town , P > 0.05), T andLsite-town could affectMBSE by negatively influencing theRnative_site and Nwater (Fig. 2F and G, Fig. 4A). Hierarchical partitioning results indicated
that Pnative_site was the most important
determinant factor for MBSE (independent effect =
54.55%), followed by Rnative_site ,Nwater , Hsite , T ,Ahabitat , and Lsite-town(independent effects were 25.84%, 13.47%, 3.67%, 1.26%, 1.09%, and
0.12%) (Fig. 5A).