Preliminary results on Exxaro relocation of baboon spiders

Adult female Golden-brown Baboon spider

The relocation of populations of the golden-brown baboon spider (Augacephalus junodi) and burst horned baboon spider (Ceratogyrus darlingi) is the first such project involving these species in southern Africa.

According to the project team, consisting of Exxaro's ecologist Koos Smit, Manketti Game Reserve research manager Marius Fuls, and entomologist Dr Dawid Jacobs, who was appointed to conduct the relocation and research, the project enables the company to mitigate the impact of its operations on biodiversity by relocating these spiders.

"We now know that, if we need to relocate such spiders in future, we have successfully done the science, and this will speed up future processes. The research and findings have given Exxaro not just the ability to re-establish an ecosystem functioning quicker in rehabilitated areas, but following publication of our methods, they will provide other industrial operations with an effective method to help re-establish a particular species in disturbed areas successfully," said Smit.

Relocated successfully

"The research findings also indicate that these species can be relocated successfully to ensure the survival of individuals and populations. Dr Jacobs is of the opinion that the relocation methods that have been tested will probably be applicable to most other baboon spider species as the two species that were relocated are the most common species," he added.

The project came about due to the Medupi power station construction activities. The role players included Eskom and the Exxaro Grootegeluk Medupi Expansion Project teams.

During the vegetation clearing phase in March 2012, baboon spiders were observed along the roads and suggestions were made to move them to a safer area as they are long-living invertebrates protected under the National Environmental Management: Biodiversity Act. The spiders are protected due to being regularly caught illegally for the pet trade, but the two species used in this project are not endangered.

A desktop study and advice provided by spider specialists Dr Ansie Dippenaar and Dr Dawid Jacobs of the University of Pretoria, revealed there was no proven method for the relocation of baboon spiders. Exxaro, with inputs from Dr Jacobs, agreed to initiate a scientific research project to determine if the two species of baboon spiders could be relocated successfully.

Research objectives

Broadly, the research objectives were to:

• Determine the most effective method of baboon spider relocation by testing different options, including the provision of man-made burrows (200 releases);
  
• Determine if the two species of baboon spiders can construct their own burrows after relocation (80 releases);
  
• Test the research theory and findings by relocating 60 individuals of the species to a rehabilitation site where they used to occur prior to construction, but disappeared due to the industrial disturbance.

The latter objective emerged after the launch of the project when Eskom offered a nearby rehabilitated site for such a test at the Matimba power station.

The research process involved identifying a relocation site in Exxaro's nearby Manketti Game Reserve, creating a relocation plan and establishing a relocation method. All this was done in consultation and with scientific inputs from Dr Jacobs.

During transect walks along nearly 30km of roadside, Koos Smit, together with members of the local community, Grootegeluk's environmental specialist Filomaine Swanepoel and rangers from Manketti Game Reserve, recorded and marked some 175 baboon spider burrows.

Capturing the spiders

Transferring of an adult female Golden-brown Baboon spider.

Exxaro then put the job of capturing the spiders out to tender and engaged Marius Koekemoer, a local resident of Lephalale with extensive knowledge about reptiles and spiders, (and moreover with a government permit to remove the spiders from the wild) to remove them from the site. Koekemoer worked with two research technicians, Bianca Smith and Roelien Jacobs, to capture the spiders over a period of three weeks in March 2012. Overall they removed 175 individuals of the two species along the Nelson Mandela Road and another 376 along the Kuipersbult Road. In some cases the burrows marked were occupied by wolf spiders. A few trapdoor spiders of interest were also recorded and sent for identification and record keeping purposes to the National Collection of Arachnida in Pretoria. Koekemoer then kept and fed the spiders until they could be relocated in the Manketti Game Reserve. Individuals collected in the same area were marked for relocation together, in order to minimise the impacts on the population.

The habitat of sub-populations was investigated to determine acceptable habitat conditions. Aspects considered included substrate structure and texture; soil moisture; vegetation type and density; food-source availability (invertebrates) and vegetation canopy cover.

An 800ha portion in the south of the Manketti Game Reserve, some 5-10km from the capture site, was identified as a suitable new habitat. The area was screened and a natural population of baboon spiders identified and used as a naturally occurring control population.

Four relocation periods were planned: the first happened in the second half of August 2012, after the coldest part of winter. The second and third relocations were made in October and November 2012 after the first summer rains.

Artificial burrows

Artificial burrows were created using hand-made soil augers with different diameters to create 200 man-made burrows of different diameters in the ground to accommodate the baboon spiders. A steel cage manufactured by the central plate workshop team at Grootegeluk was fixed into the ground over each artificial burrow to prevent spiders from escaping until they had adopted the burrow, and to keep predators out.

Each burrow, for both the relocated and control populations was monitored weekly, directly after release, and monthly after the first three months.

A total of 80 spiders were released without burrows but in protected boxes. A number of them constructed their own burrows, but the research team believes this incidence and their survival rate would have been lower if it were not for the boxes that contained them and provided protection against predators while they constructed the burrows.

A total of 60 spiders were relocated on Eskom's rehabilitated Matimba power station ash dump in order to test the results of the research project in action.

High acceptance rate

"We said that we would be happy if over a period of one week, 50% accepted their new burrows, so we were absolutely thrilled with a 95% acceptance rate," said Marius Fuls.

"Releasing them without a ready-made burrow is not very successful. They are usually eaten by predators such as baboons, mongooses, birds and other spiders before they can build a shelter for themselves. We also observed that the time of day of relocation is important: it seemed more successful to relocate the spiders in the first half of the day in order to give them time to settle before they become active at night.

Adult, female Golden-brown Baboon spider (Augacephalus junodi)

"Of course, as Eskom provided a rehabilitated relocation test site, they're also very excited about the results. Construction company Basil Read heard about the project and brought through a number of spiders they had discovered while working on the Mokolo pipeline project in the Lephalale area, and another mining company, BHP Billiton, has expressed interest in our project as well," said Fuhls.

"I am really proud to have been involved in a project like this. It's the first time in southern Africa that such a project has been conducted, giving us an opportunity to add to the body of knowledge about spiders and contribute to scientific research. It has given us an opportunity to show that while mining will impact an area, we do have a mitigation method, thereby giving us an opportunity to meet our commitment to sustainability.

"It is another successful first for Exxaro which demonstrates our vision in action: 'Through our innovation and growth we will be a powerful source of endless possibilities'. And Exxaro and Eskom have shown that when it comes to the environment, we can work together for the benefit of the environment," he added.

Exxaro will continue to monitor the burrows of the relocated as well as the control populations to determine survival rates and will also continue to look for similar projects for future research opportunities.