On the rise: impacts and challenges in management of invasive grasses in South American savannas

The rapid spread of non-native perennial grasses across South American savannas poses a growing threat to native plant diversity and ecosystem functioning.They disrupt key ecological processes, including fire regimes, nutrient cycling and plant community dynamics, driving the loss of functional diversity and the homogenization of native vegetation.This review compiles current knowledge on the ecological impacts of the nine most invasive perennial grass species in South American savannas and the challenges faced in controlling them, with a particular emphasis on the Brazilian Cerrado.We examine the mechanisms by which they outcompete native species, alter soil-plant interactions, and inhibit natural regeneration.Particular attention is given to the ecological traits that confer competitive advantages to these invasive grasses under conditions of disturbance, increased nutrient availability and climate change.We also evaluate the challenges faced in the ecological restoration of invaded areas and discuss integrated strategies for controlling invasions and promoting the recovery of native species.This synthesis underscores the urgent need to address invasions by non-native grasses through coordinated research, new policies and management efforts aimed to safeguard the long-term biodiversity and ecological resilience of South American savannas.