Bringing ploughed fields back to nature, by counting the ants

As the South African National Parks (SANParks) expand their territories by buying up neighbouring farmlands, each new property needs to be assessed for environmental damage caused by ploughing, overgrazing, pesticides, alien plants and erosion. And one of the best ways to do that is by studying the ant population.


Land previously used for farming must first be “rehabilitated” into something resembling a natural state fit for wildlife, a process that can take years. Data from living creatures on the land can help provide a guide to levels of degradation, and the most suitable living creatures are ants.

Hendrik Sithole, research manager for invertebrates at SANParks Scientific Services, told the SANParks Times that ants were ideal because they are plentiful, less mobile than other creatures, and create their own diverse habitats within larger natural habitats.

His team collect ants from farmlands that have not yet been rehabilitated, and compare the results to land that has undergone rehabilitation or land that was never degraded by farming. They have found that the more degraded the land, the lower the ant population. “There is one degraded site in Mountain Zebra National Park where the ant abundance was 16 times less than what we found at a site that was not degraded,” said Sithole.
He also found that the variety of ant species was significantly lower on degraded sites.

Since ants are extremely sensitive to soil conditions, degradation of soil conditions has an immediate effect on them. The ants are therefore an ideal barometer of the success of rehabilitation projects.

Source: SANParks Times, June 2017