Abstract:

Wind-farms threaten Southern Africa’s cliff nesting vultures

Ian Rushworth, Sonja Krüger

Ezemvelo KZN Wildlife, P.O. Box 13053, Cascades, 3202, South Africa

The Lesotho and South African governments have signed an agreement for the development of wind-farms in the highlands of the Maluti-Drakensberg mountains.  The range of the remaining 100 pairs of the endangered Bearded Vulture Gypaetus barbatus is restricted to the Maluti-Drakensberg mountains which is also home to 20% of the global population of the southern African endemic Cape Vulture Gyps coprotheres.  The potential effects of proposed wind energy developments on these two threatened species of cliff nesting vultures are explored.
As wind-farms are a new development in Africa, no quantitative data exists as to the extent to which wind-farms will kill vultures.  However, international experience indicates that vultures are extremely susceptible to being killed by rotor blades, because of a combination of their lack of forward visual field, their foraging behaviour and lack of ability to take rapid avoidance action.  It can be expected therefore that wind energy developments in the Maluti-Drakensberg mountains will have negative impacts on already declining populations of vultures.
Long term monitoring of vulture populations and data from 20 tagged Bearded Vultures since 2007 however provides a unique opportunity of having a pre-construction population status baseline, but has also provided detailed information on use of habitat for foraging, ranging behavior of different age classes, and flying height.  This information, together with published information from other studies, was incorporated into Population Viability Models to assess the potential impacts of different scenarios of wind-farm development.
Mortalities as a result of collisions with wind-farm structures were included in the model as a combination of increased age-specific mortality rates and/or additional harvest. The resultant impact of mortalities from wind-farms was extreme, with Bearded and Cape Vulture populations rate of decline increasing from the current -1.1% and -2% per annum respectively to in excess of -5% per annum. The models predict a devastating impact of wind-farms, with a high probability of both populations going extinct.  So-called ‘clean’ energy is not synonymous with ‘green’ energy.

Presentation Topic

Wind-farms threaten Southern Africa’s cliff nesting vultures

 

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Ezemvelo KZN Wildlife, P.O. Box 13053, Cascades, 3202, South Africa

 

 

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