Propagule pressure, invasibility of freshwater ecosystems by macrophytes and their ecological impacts: a review of tropical freshwater ecosystems

Abstract

In this review, we aim to draw parallels between the principal concepts of invasion biology, developed mainly for terrestrial plants in temperate regions, with findings for macrophytes recorded in tropical inland waters. In these ecosystems, the most important abiotic and biotic filters influencing invasion success are related to water and sediment conditions, light, disturbance, hydrology and the diversity and density of native species. The main impacts are related to direct and indirect changes in the populations and communities of native macrophytes and other associated organisms. Non-native ecosystem engineer species of macrophytes can affect ecosystems directly, and after affecting ecosystems, their effects can extend to populations and communities. High plant growth rates in the tropics could lead to rapid invasion and larger impacts compared to temperate ecosystems. Although we found many parallels between ecosystems regarding the general concepts of invasion, areas that should receive further investigation in the tropics include (i) the synergistic interaction of multiple invasive species, (ii) the effects of regime shift on invasion success and vice versa and (iii) how climate change will affect the dynamics of macrophyte invasion in tropical ecosystems.