Taking stock of the impact of the 2014–19 drought on the biodiversity of Phalaborwa

By Dr Anthony M Swemmer and Rion Lerm, SAEON Ndlovu Node Tweet

The small town of Phalaborwa (Limpopo Province) is encircled by a diversity of land-use types, including a national park, private game reserves, rural rangelands and mining.

From 2012 to 2019, staff and students of the SAEON Ndlovu Node conducted a range of surveys on various plant and animal groups inhabiting these areas, and the recent drought provided a rare opportunity to record how ecological disturbance interacts with drought.

While numerous plant species have suffered, results of many of the animal taxa show a surprisingly high level of resilience.

The recent drought in the Phalaborwa area provided a rare opportunity to record how ecological disturbance interacts with drought (Photo: Shutterstock)

Much of this work was funded by the Palabora Mining Company, and the project focused on comparing the biodiversity of the extensive rehabilitation areas of the mine with neighbouring protected areas. The largely unrestricted movement of animals into the mining area has meant that rehabilitation in these areas has proceeded in the presence of natural herbivores such as elephant, buffalo, kudu and blue wildebeest, which regularly move up onto man-made structures to feed.

A camera trap network operated by SAEON from 2012 to 2018 recorded a remarkable 22 species of large mammals on each of the mine rehabilitation areas, compared with 33 in a neighbouring game reserve. A few of these species, such as buffalo, were recorded more frequently on the rehabilitation areas than in the natural areas next door, including during the drought years.

Bird surveys conducted by the node’s technician, Rion Lerm, revealed that the diversity of birds was little affected by the drought, with more species recorded at the end of the drought than at the start at some sites.

Bird surveys revealed that the diversity of birds was little affected by the drought The sabota lark, one of the common bird species in the area (Copyright: Rion Lerm)

The Ndlovu Node’s technician, Rion Lerm, conducts a bird survey (Copyright: Rion Lerm)

Vegetation surveys initially conducted by SAEON students from North-West University, and recently repeated by SAEON MSc student Clarissa Minnaar, revealed the severity of the impact of the drought on the productivity and diversity of herbaceous plants (grasses and forbs). While the rehabilitation areas have always supported a far lower number of species, reductions in species richness were fortunately not as severe there as in the neighbouring protected area.

Vegetation surveys revealed the severity of the impact of the drought on the productivity and diversity of herbaceous plants SAEON MSc student Clarissa Minnaar (left) conducts a vegetation survey (Photo: Tony Swemmer)

Other surveys conducted over the past seven years, on dung beetles, dragonflies, reptiles, amphibians and rodents, have produced additional baseline data which can be used for future studies on long-term changes in the biodiversity of competing land uses.