Environmental Impact of Invasion by an African Grass (Echinochloa pyramidalis) on Tropical Wetlands: Using Functional Differences as a Control Strategy

Abstract

Tropical wetlands are commonly used for cattle ranching and have been modified either by draining them or introducing non-native species that are palatable to cattle. Some of these introduced species have become wetland and dune invaders. In Mexico, the introduction of antelope grass (Echinochloa pyramidalis) and its effects are being documented. This grass species is highly appreciated by cattle ranchers and is invading natural wetlands. It has C4 photosynthesis, high biomass production and high vegetative propagation, is tolerant to grazing and able to grow in both flooded and dry conditions. It is reducing plant biodiversity by increasing its own aerial coverage, changing wetland hydrology, reducing faunal habitat and causing soil physicochemical changes (e.g. vertical accretion). Reducing its dominance and increasing the density of native wetland species is difficult, expensive and time-consuming. We began a restoration project in a coastal wetland in central Veracruz, Gulf of Mexico, which included using shade to control the invader. This strategy reduced E. pyramidalis cover and increased the cover of native species, highlighting the importance of understanding the functional differences between native and invasive species when developing strategies for the control and eradication of problematic species.