- A study from central Karnataka that analysed the responses of birds and mammals to the wind turbines, found that species richness, abundance, and unique species of birds were relatively higher in areas without wind turbines over wind turbine sites.
- Raptors such as hawks, kites or eagles, and bats, are highly vulnerable to wind turbines due to chances of direct collision. Blackbucks, chinkaras, golden jackals and jungle cats were less likely to occupy sites with a high number of wind turbines, the study found.
- Researchers and wildlife conservationists note that wind energy and its impact on biodiversity is an understudied subject in India and recommend long-term assessments in important landscapes that are suited for windfarms, to ensure wind energy development is environmentally responsible.
Despite the increasing expansion of wind energy in India, research on the impact of windfarms on terrestrial mammals is limited. A recent study, published earlier this year, addresses this knowledge gap. It assesses the responses of birds and mammals to the wind turbines in central Karnataka. In the study conducted from January 2016 to May 2018, the researchers investigated the fatality rate of birds due to collision with wind turbines, the response of the diversity and composition of birds and the occupancy pattern of terrestrial mammals in the windfarms located in the Chitradurga and Gadag districts.
Wind turbines have been known to stand as a threat to airborne species such as bats and birds, which often die due to collision with the rotor blade of the wind turbine. In India, the conversation about the impact of windfarms on biodiversity, especially birds, is increasing. A case in the Supreme Court is considering the impact of wind power projects on the population of birds, including the critically endangered great Indian bustard (GIB), in Gujarat and Rajasthan, as there are reports of deaths due to collision with the turbines. In Tamil Nadu (the state with 25 percent of India’s total wind energy capacity) harriers seem to be avoiding areas dominated by windfarms, as indicated in the initial observations, as part of an ongoing study.
In the Karnataka study, the researchers found that the selection of sites to set up windfarms is a major factor that can influence the wildlife around it. “If it (the wind turbine) is on the migratory path of birds or bats, or wildlife habitats, or close to water bodies, then a negative impact can be expected. Otherwise, there’s no impact,” says Honnavalli N. Kumara, Principal Scientist – Conservation Biology, Salim Ali Centre for Ornithology and Natural History, and lead author of the study.
Also, certain species tend to be impacted more than others. Birds, particularly raptors such as hawks, kites or eagles, and bats, are highly vulnerable due to direct collision. “Certain species of animals on the ground get displaced,” adds Kumara, stating that this can have a lasting impact on the area’s biodiversity.
This is consistent with the findings of the report, which confirm that the mean annual animal fatality rate per wind turbine was 0.26/year. Species richness, abundance, and unique species of birds were, relatively higher in control sites (adjoining areas without wind turbines, but with a similar habitat) over wind turbine sites. This important finding indicated that certain species tended to avoid the surroundings of windfarms for foraging, nesting and roosting, thus reducing the activity of those species in the immediate footprint of turbines.
The study evidences that blackbucks, chinkaras, golden jackals and jungle cats were less likely to occupy sites with a high number of wind turbines, whereas four-horned antelopes favoured the area. While the abundance of wind turbines did not play a major role in the occupancy of a few species, the avoidance of wind turbines by many mammals should be a cause for concern to the management of the forested area, where the wind turbines are established, noted the study.
“At the moment, there is no documentation on whether the presence of long-established wind turbines can wipe out an entire species. There’s no information available about places in India where wildlife is in direct conflict with windfarms, and no government guidelines on how to mitigate it. This is a poorly studied area, and a lot more needs to be done,” says Kumara.
In India, the renewable energy sector has grown at a compounded annual growth rate of 15.51 percent in the last five years. Wind energy, specifically, has grown at a rate of about eight percent. While this is positive from a climate change mitigation perspective, there are also side effects that impact biodiversity.
The threat from windfarms, however, is one among many threats that bird populations around the world face such as the rise of invasive species and pesticide poisoning, collision with windows and predation by outdoor cats. Then there’s also climate change and habitat loss. The 2020 State of India’s Birds report found that half of the avian species were on the decline in the country, with endemic species, birds of prey, and those dwelling in forests and grasslands, being the most vulnerable.
Work in progress
The establishment of windfarms may rise in the future, not only in India, but globally. To meet its renewable energy targets, India needs an area almost the size of Bihar, primarily consisting of open natural ecosystems. Windfarms are mostly located in these open natural ecosystems with rich biodiversity. Therefore, it is important to understand the sensitive biodiversity present in these landscapes before installing wind turbines.
The study, initiated by the Karnataka Forest Department (Bengaluru) recommends that before installing turbines at a site or before licensing new windfarms in forested areas, in the vicinity of the forest patches or next to wetlands, there should be a critical evaluation of animal diversity, especially the birds and their seasonal movements, occupancy and abundance of mammals, and possible impact on them. “These small measures could support responsible wind energy development in a biodiversity-friendly way,” says Abhay Jha, a wildlife conservationist based in Karnataka.
To overcome some challenges in site selection, the researchers suggest measures such as retaining a portion of hill regions or natural habitat in the wind turbine-dominated terrain as refugia for animals. There also needs to be long-term monitoring of the biodiversity around the existing windfarms, they say. Studies on raptors and their food resources like rodents, reptiles are essential to understanding the consequences of turbines. “Such studies could help in the management and mitigation of the impact caused by wind turbines,” says Jha.
While there is growing realisation about the conflicts arising between its deployment of wind energy and wildlife conservation at a local level, more research on this front is needed. Among initiatives working towards a better understanding of the situation, is the Bird Sensitivity Map for India created by the Bombay Natural History Society in collaboration with Birdlife International. The map, expected to be available by the end of 2022, will be useful for setting up windfarms and transmission lines and help in site selection with the least impact on birds.
Globally there are also efforts to mitigate the impact of windfarms on birds. For example, WindEurope, which advocates wind energy policies for Europe, launched a paper in 2017 that provides practical information on the mitigation measures to reduce wind turbine impact on wildlife. It recommends, placement of infrastructure, at the outset, in a way that can avoid impacts on biodiversity, followed by reduction, compensation and offsetting steps to minimise wind turbine impacts.
Banner image: As per a recent study in central Karnataka, blackbucks were less likely to occupy sites with high number of wind turbines. Photo by CRaghavan/Wikimedia Commons.