Lighting up the African continent what does this mean for our birds? JON SMALLIE¹, MEGAN DIAMOND 1 AND ANDREW JENKINS 2 ¹ Wildlife & Energy Interaction Group, Endangered Wildlife Trust, Private Bag X11, Parkview 2122, Johannesburg, South Africa. jons@ewt.org.za 2 AviSense Consulting, 10 Harrier Circle, Imhoff s Gift, Kommetjie, South Africa Smallie, J., Diamond, M. & Jenkins, A. 2009. Lighting up the African continent what does it mean for our birds? pp. 38 43. In: Harebottle, D.M., Craig, A.J.F.K., Anderson, M.D., Rakotomanana, H. & Muchai. (eds). Proceedings of the 12th Pan-African Ornithological Congress, 2008. Cape Town, Animal Demography Unit. (ISBN: 978-0-7992-2361-3) Keywords: power lines, electrification, electrocution, collision Increasing access to electricity has been recognised by most African leaders, fora and unions as a top priority for the continent. In South Africa (the most electrified African country to date), the Eskom Endangered Wildlife Trust Strategic Partnership was initiated in 1996 in response to the impacts of electrical infrastructure on birds and wildlife. This unique partnership has gained valuable experience in the various interactions between birds and electrical infrastructure. Interactions that are now well understood include collision of birds with overhead cables, electrocution of birds on poles, nesting of birds on poles, electrical faulting caused by birds (direct impacts). Experience has shown that the birds most prone to these interactions include vultures, eagles, cranes, bustards, storks, and flamingos. Indirect impacts include habitat destruction and disturbance. Although there appears to have been little concern for bird power line issues in African countries north of South Africa to date, this is likely attributable to the relative lack of power lines. There is good reason to expect the abovementioned impacts to emerge north of South Africa as increased electrification takes place on the continent. An opportunity exists to ensure that electrification takes place in as bird-friendly a manner as possible, thereby avoiding the early mistakes made in South Africa, where large scale electrification took place before an understanding of the impacts of power lines on birds existed. INTRODUCTION The World Bank (African Development Indicators) estimates that fewer than 5% of sub-saharan Africans have access to reliable electricity (www.worldbank.org/afri/adi2007, 2007). Increasing this access to electricity has been recognised by most African leaders, fora and unions as a top priority for the continent. Electrification will require power generation and distribution of this power to the end users, requiring thousands of kilometres of overhead power lines crossing our continent. In South Africa (certainly the most electrified African country to date), the Eskom Endangered Wildlife Trust Strategic Partnership was initiated in 1996 in response to the impacts of electrical infrastructure on birds and wildlife. This unique partnership between an electrical utility and a conservation non profit organisation has gained valuable experience in the various interactions between birds and electrical infrastructure. DISCUSSION The South African experience The Eskom EWT Strategic Partnership has over the years identified several interactions between birds and electrical infrastructure that are now well understood. These can be categorised into conservation and business impacts, both direct and indirect. Direct conservation impacts Collision of birds with overhead cables A bird collision occurs when a bird in mid-flight does not see the overhead cables until it is too late to take evasive action. In very low light or no light conditions birds may not see the lines at all. This results in the bird colliding with the cables, and usually dying through injuries related to the impact with the cable or the subsequent impact with the ground. The species that are most vulnerable to this impact are the large, heavy bodied birds with limited agility in flight. These flight characteristics make it difficult for the bird to take evasive action to avoid colliding with cables (Anderson 2001, van Rooyen 2004) Bird families most vulnerable to collision include the cranes, storks, bustards, flamingos and various water birds. Factors that influence the likelihood of a collision occurring include: weather; topography; habitat; land use; power line structure and height; power line orientation; and wind. Electrocution of birds on poles and in substations A bird electrocution occurs when a bird is perched or attempts to perch on the electrical structure and causes an electrical short circuit by physically bridging the air gap between live components and/or live and earthed components (van Rooyen 2004). The risk of an electrocution occurring on a given structure is determined by the physical clearances between 38
Smallie et al.: Effect of electification of Africa on birds 39 Fig. 1. Reported mortality of birds (per family) and mammals through both electrocution and collision, August 1996 to July 2008 (Eskom Endangered Wildlife Trust Strategic Partnership 2008a). Families comprising predominantly threatened species are shown in red. the relevant hardware, and the size of the bird. Large birds are more at risk, as they have a greater likelihood of bridging these clearances, either with their wingspan, or their tip of toe to tip of beak dimension. Families of birds most at risk include the vultures, eagles, storks and herons. Factors that affect the likelihood of an electrocution occurring include bird species, bird behaviour, and pole or pylon structure and dimensions. Figure 1 shows the number of reported bird collisions and electrocutions of birds and mammals, for the period August 1996 to July 2008 (Eskom Endangered Wildlife Trust Strategic Partnership 2008a). The likelihood of detection of bird carcasses is relatively low due to vegetation cover, and natural decomposition and scavenging of carcasses. This means that the vast majority of bird mortalities go unreported. Nesting of birds on poles and towers Power lines often represent suitable nesting substrate for certain bird species, in particular in arid regions, where natural nesting substrate such as trees may be absent. Large eagles such as Martial Polemaetus bellicosus and Verreauxs Aquila verreauxii Eagle have been recorded nesting on transmission (>132 000 volts) lines in the Karoo region since the 1990s. A helicopter survey in August 2006 revealed 132 eagle nests, 44 of which were active, on 1400 km of transmission line in predominantly Nama Karoo Biome (Jenkins et al. 2007). The nesting species were Martial Eagle, Tawny Eagle Aquila rapax and Verreaux s Eagle. Another species that appears to be taking advantage of power pylons as nesting substrate is the Sociable Weaver Philetairus socius. Whilst power lines may assist certain species in breeding, it comes with a set of risks. Firstly, nests can in some cases cause electrical faults. Secondly, often utility maintenance staff assumes nests to be problematic and remove them, with obvious conservation implications. Roosting of birds on poles and towers Similarly to nesting as described above, electrical infrastructure has provided safe roosting sites for certain species which have adapted to roosting on these structures, such as Southern Bald Ibis Geronticus calvus, Cape Vulture Gyps coprotheres, Black-headed Heron Ardea melanocephala, and Cape Crow Corvus capensis. This provision of artificial roosts potentially allows species to occupy areas where they were previously excluded. Indirect conservation impacts Destruction of bird habitat during construction and maintenance of infrastructure During the construction phase and maintenance of power lines and substations, a certain amount of habitat destruction and alteration inevitably takes place. The construction of access roads, clearing of servitudes and the levelling of substation yards, all require the removal of natural vegetation. Once operational, power line servitudes have to be regularly cleared of excess vegetation to allow access to the line for maintenance, and to minimize the risk of fire under the line. Any removal of natural vegetation results in a change to the habitat available to the birds of the area, potentially impacting on the birds that occupy these sites ability to breed, forage and roost in the vicinity. Disturbance of birds during construction and maintenance of infrastructure The above described activities can also impact on birds through disturbance of their daily activities, in particular breeding. This is most likely during construction, when vehicle and human activity on the site is at a peak. Range expansion due to provision of artificial perching and nesting substrate As described above, the construction of power line infrastructure has provided perching and nesting substrate for certain bird species in areas where the natural vegetation did not previously meet the requirements. It is suspected that this might result in a range expansion for certain species, with a
40 12th Pan-African Ornithological Congress ISBN: 978-0-7992-2361-3 Fig. 2. Distribution of four crane species in Africa. (Data from BirdLife International & International Crane Foundation.) host of secondary ecological effects, including competition with other bird species for resources (food and nesting sites). Direct business impacts Electrical faulting caused by birds Birds are able to cause electrical faults on power lines through a number of mechanisms, including bird streamers, bird pollution and bird nesting. This faulting lowers the quality of electrical supply to the end customers, which in turn impacts on the electrical utility s business. Both bird streamers and bird pollution occur as a result of birds perching on pylons or towers, often directly above live conductors. Mitigation and management methods to reduce the extent and significance of the above interactions have been developed in South Africa over the years, in an effort to ensure that electricity is supplied with as little impact on our birds as possible. LIGHTING UP AFRICA AND THE BIRDS? In South Africa, huge lengths of power line were constructed prior to an understanding of the potential impacts on birds, and a massive task now exists to address this infrastructure reactively. An opportunity exists through much of Africa to avoid making these mistakes, and build the power lines in a safe manner from the start. All of the families of birds that have proven to be vulnerable to electrical infrastructure in South Africa are well represented across much of the African continent, as shown by Figures 2, 3 and 4. Since power line design and construction is very similar within the region, similar impacts can be expected to occur. The reason these impacts have not been more evident in other African countries to date include: the relative lack of power lines in these landscapes to date; the relatively low awareness of these interactions amongst the electrical, conservation and public sectors; the low likelihood of detecting bird carcasses in some habitats Figures 5, 6 and 7 show the layout of the planned transmission Power Corridors emanating from only one proposed power generation source, i.e. the Inga Hydroelectric Scheme on the Congo River in the Democratic Republic of Congo (various unpublished sources at World Energy Council s International Forum on the Grand Inga Project, 2007). It is clear that there is huge spatial overlap with the distributions of the families discussed above. In addition, each of these power corridors will give rise to an even greater length of secondary transmission (>132 000 volts) line (hypothetically illustrated in Figures 5 7), and ultimately distribution (<132 000 volts) power line. In South Africa, the ratio of transmission line length to distribution line length is roughly ten to one ( Eskom Endangered Wildlife Trust Strategic Partnership 2008b). One can therefore multiply the power line network shown in the above figures by ten to get an indication of how much distribution line to expect emanating from Inga. CONCLUSION The South African experience has shown that significant impacts on birds can occur with electrification. The relative lack of electrification to date in many African countries provides
Smallie et al.: Effect of electification of Africa on birds 41 Fig. 3. Distribution of three vulture species in Africa. (Data from BirdLife International & International Crane Foundation.) Fig. 4. Distribution of the Lesser Flamingo in Africa. (Data from BirdLife International & International Crane Foundation.)
42 12th Pan-African Ornithological Congress ISBN: 978-0-7992-2361-3 Fig. 5. Distribution of four crane species, and position of planned and possible power lines emanating from Inga Hydroelectric Scheme. Fig. 6. Distribution of three vulture species, and position of planned and possible power lines emanating from Inga Hydroelectric Scheme.
Smallie et al.: Effect of electification of Africa on birds 43 Fig. 7. Distribution of the Lesser Flamingo, and position of planned and possible power lines emanating from Inga Hydroelectric Scheme. an opportunity to incorporate the South African knowledge into future electrification from the start. Experience now needs to be transferred to electrical utilities and environmental and conservation organisations in these countries in preparation for the future electrification. REFERENCES Anderson, M.D. 2001. The effectiveness of two different marking devices to reduce large terrestrial bird collisions with overhead electricity cables in the eastern Karoo, South Africa. Draft report to Eskom Resources and Strategy Division. Johannesburg, South Africa. Eskom Endangered Wildlife Trust Strategic Partnership. 2008a. Central Incident Register. Unpubl. Report. Eskom Endangered Wildlife Trust Strategic Partnership. 2008b. Geographic Information System. Unpubl. Report. Jenkins, A., de Goede, K. & van Rooyen, C. 2007. Improving the products of the Eskom Electric Eagle Project. Unpubl. report to Eskom Transmission. van Rooyen, C.S. 2004a. The Management of Wildlife Interactions with overhead lines. In: The Fundamentals and Practice of Overhead Line Maintenance (132kV and above). pp. 217 245. Eskom Technology, Services International, Johannesburg. Van Rooyen, C.S. 2004b. Investigations into vulture electrocutions on the Edwardsdam Mareetsane 88kV feeder. Unpubl. report. Endangered Wildlife Trust, Johannesburg. World Bank. 2007. African Development Indicators 2007.