Antagonistic and cumulative effects of connectivity: a predictive model based on aquatic vegetation in riverine wetlands

The effects of connectivity cannot be reduced to a simple gradient. River o verflows disturb the vegetation of connected wetlands but, reducing competi tion, promote plant diversity. Overflows also bring nutrients, silt and pla nt propagules. Nutrients increase eutrophication and promote phytoplankton development, which reduces water transparency and impedes the growth of roo ted plants. Silt inputs accelerate terrestrialization but provide regenerat ion niches that favour the recruitment of allochthonous propagules. These m ultiple effects are combined into a model that predicts diversity and life- history traits of aquatic plants (growth form, potential size, phenology an d frequency of flowering, vegetative reproduction and defence against herbi vores) in relation to the connectivity of the riverine wetlands.