An urgent need to confront Nassella in SA

South American grass species from the genus Nassella were unwittingly introduced to South Africa over 120 years ago and continue to invade montane veld. As Mike Burgess writes, research-based action is required.

- Mike Burgess

When the British Army sourced horse feed from Argentina for their war effort against the Boers between 1899 and 1902, serrated tussock grass (Nassella trichotoma), Chilean needlegrass (N. neesiana) and Mexican feather grass (N. tenuissima) were unwittingly introduced to South Africa.

By the mid-1900s these species had become naturalised to higher-lying veld, and in the 1970s, state-funded research and control campaigns (mainly spraying herbicides) were launched to curb their spread. However, these efforts were abandoned in 2000.

Since then, these unpalatable Nassella grass species have continued to proliferate in South African veld.

According to Centre for Invasion Biology-funded (CIB) PhD student Anthony Mapaura – who in 2020 completed an extensive literature review on Nassella with the support of researchers at CIB, Rhodes University, and the University of the Free State’s QwaQwa campus – urgent action is required to curb the environmental and socio-economic impacts of these exotic grasses.

NEGATIVE IMPACTS

Exotic