Impacts of power infrastructure
This project attempts to mitigate the impacts of power generation and transmission infrastructure on birds and other biota. Initial attention was focused on collision impacts associated with powerlines, which mainly affect large, open-country birds such as bustards and cranes that are unable to react rapidly when they encounter aerial obstructions. More recently the project has considered the impacts of renewable energy technologies, including wind and solar power generation.
Wind and solar power generation have much less broad-scale environmental impact than the coal-fired power stations on which South Africa relies for most of its power generation, but both technologies can have significant impacts at a local scale. The aim of this programme is to provide practical solutions to reduce the impacts of renewable energy projects, as well as energy transmission infrastructure, on birds in southern Africa. The programme is run in close collaboration with BirdLife South Africa’s Birds and Renewable Energy programme and the Endangered Wildlife Trust. Modelling the impacts of wind farms on Verreaux’s Eagles Aquila verreauxii is reported separately in the section “Conserving Verreaux’s Eagles”.
Activities in 2018
- CB MSc student Sydney Davies completed her research project with Tanya Smith (EWT) on GPS-GSM tracking of Blue Cranes Grus paradisea in the Overberg. Christie Craig, a former CB MSc student, was recruited by the EWT to take this work forward, and will register for a PhD in 2020. More GPS-GSM tags were deployed on cranes in the Overberg, Swartland and eastern Karoo. The Bateleurs kindly arranged two flights in August and September to count Blue Cranes in the Swartland and Overberg, respectively. The Overberg population was estimated as 39000±7000 (SE) birds, roughly six times the population in 1993. We hope to be able to repeat these flights in 2019, and to include a summer count when the cranes are more dispersed, narrowing our confidence in the resultant population estimates. We are particularly grateful to Mark Rule for safely conducting the survey flights.
- A final report was delivered to ESKOM on Jess Shaw’s large-scale experiment to test the efficacy of transmission line marking (using flappers or static flight diverters) to reducecollision mortality. This study, set up in the De Aar region of the eastern Nama Karoo, was a partnership between ESKOM, the Endangered Wildlife Trust (EWT) and UCT. Jess, now based in Scotland, and former post-doc Tim Reid, now based in Australia, completed analyses of the collision data to show that marking lines reduces collisions of Blue Cranes, but has no significant benefit for Ludwig’s Bustards Neotis ludwigii. A paper on this very important experiment should be completed in 2019.
- Vonica Perold and Peter Ryan worked with Sam Ralston-Paton (BLSA) to review bird mortality monitoring reports at wind turbine facilities around South Africa. So far 130 species of birds have been reported killed at 20 windfarms, with raptors and swifts making up the majority of casualties. Species accumulation models suggest that around 40% of species found in the vicinity of wind farms will be killed at least occasionally. The average mortality rate averaged 1.0 bird per turbine per year, but this increased to aroundfive birds per turbine per year once the biases introduced by imperfect carcass detection and scavenger removal were factored into the estimate.
- There have been few studies of windfarm impacts on birds in the Southern Hemisphere, so we can use the collision rates observed in South Africa to test the utility of a model estimating collision risks for terrestrial bird species developed using data from facilities in the Northern Hemisphere. The mortality rates recorded in South Africa were correlated with the predicted values, but the relationship was weak, with predicted values explaining only 8-15% of the variation in observed collision rates among species.
- Vonica also helped CB MSc student Corey Jeal to publish two papers arising from his study of a concentrated solar power (CSP) ‘trough’ facility, Bokpoort, near Groblershoop in the Northern Cape. The paper in press with Ostrich shows that the impacts on birds and other large charismatic animals are relatively small, with the biggest threat posed by drowning in the plant’s evaporation ponds. Fitz RA Colleen Seymour assisted with the paper on changes in macro-invertebrate communities at the site, now in press with Journal of Arid Environments.
- Robin Colyn (BLSA) started fieldwork to better understand the factors determining the distributions of range-restricted larks in the Karoo regions of southern Africa. The Red Lark Certhilauda burra is a species of particular concern, given the large number of wind energy projects planned in the range of this localised, vulnerable species. Using a range-finder that also measures the angle of elevation, he was able to show that average flight height of displaying males is around 50 m, which definitely places them at risk of collisions (blade heights range from 25-60 m above the ground). Some larks were recorded displaying at more than 150 m elevation, and Robin is trying to determine the effect of wind strength on display height. Initial results suggest that birds might fly higher when wind speeds are low.
- Sydney Davies obtained her MSc on habitat use and movements of Blue Cranes in the Overberg.
- Elke Visser’s paper showing the relatively minor impacts of utility-scale photovoltaic solar power generation on birds in the Northern Cape was published online in Renewable Energy.
- Two papers from Corey Jeal’s CB MSc project on the impacts of a concentrated solar power ‘trough’ facility are now in press.
Endangered Wildlife Trust-Eskom Strategic Partnership; The Bataleurs, Hans Hoheisen Charitable Trust, Leiden Conservaiton Fund, Dave Myers.
Prof. Peter Ryan (FIAO, UCT)
Dr Arjun Amar (FIAO, UCT)
Robin Colyn (BLSA)
Christie Craig (EWT)
Dr Andrew Jenkins (FIAO, UCT)
Dr Me gan Murgatroyd (FIAO, UCT)
Vonica Perold (FIAO, UCT)
Samantha Ralston-Paton (BLSA)
Dr Tim Reid (ANU, Canberra)
Dr Jess Shaw (Scottish Natural Heritage)
Tanya Smith (EWT)
Students: Sydney Davies (CB MSc, UCT)