The effects of powerlines on bustards: how best to mitigate, how best to monitor?

Abstract

Summary Bustards comprise a highly threatened family of birds and, being relatively fast, heavy fliers with very limited frontal visual fields, are particularly susceptible to mortality at powerlines. These infrastructures can also displace them from immediately adjacent habitat and act as barriers, fragmenting their ranges. With geographically ever wider energy transmission and distribution grids, the powerline threat to bustards is constantly growing. Reviewing the published and unpublished literature up to January 2021, we found 2,774 records of bustard collision with powerlines, involving 14 species. Some studies associate powerline collisions with population declines. To avoid mortalities, the most effective solution is to bury the lines; otherwise they should be either routed away from bustard-frequented areas, or made redundant by local energy generation. When possible, new lines should run parallel to existing structures and wires should preferably be as low and thick as possible, with minimal conductor obstruction of vertical airspace, although it should be noted that these measures require additional testing. A review of studies finds limited evidence that ‘bird flight diverters’ (BFDs; devices fitted to wires to induce evasive action) achieve significant reductions in mortality for some bustard species. Nevertheless, dynamic BFDs are preferable to static ones as they are thought to perform more effectively. Rigorous evaluation of powerline mortalities, and effectiveness of mitigation measures, need systematic carcass surveys and bias corrections. Whenever feasible, assessments of displacement and barrier effects should be undertaken. Following best practice guidelines proposed with this review paper to monitor impacts and mitigation could help build a reliable body of evidence on best ways to prevent bustard mortality at powerlines. Research should focus on validating mitigation measures and quantifying, particularly for threatened bustards, the population effects of powerline grids at the national scale, to account for cumulative impacts on bustards and establish an equitable basis for compensation measures.

Deployment of Solar Energy at the Expense of Conservation Sensitive Areas Precludes its Classification as an Environmentally Sustainable Activity

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Detailed mapping of protected species distribution, an essential tool for renewable energy planning in agroecosystems

“…A large-scale experiment demonstrated that line marking reduces power line collision mortality in large terrestrial birds, but not in bustards (Shaw et al, 2021). For these reasons, underground cabling is the only solution that completely prevents bird collisions (Silva et al, 2022). For instance, in Austria and Hungary, extensive underground cabling of distribution lines was implemented in an important area for great bustards.…”

“…In addition, overhead power lines cause collision fatalities and are a major source of direct anthropogenic bird mortality (Loss et al, 2015), especially in large birds such as cranes, storks, or bustards (Bernardino et al, 2018). Bustards (family Otididae) are among the birds most vulnerable to collision with power lines, and collision losses represent the major cause of mortality in many of threatened species of this family (Burnside et al, 2015;Collar et al, 2017;Dutta et al, 2011;Garcia del Rey and Rodriguez-Lorenzo, 2011;Jenkins et al, 2011;Mahood et al, 2018;Marcelino et al, 2018;Marques et al, 2021;Reiter, 2000;Shaw, 2013;Shaw et al, 2018;Silva et al, 2010Silva et al, , 2022Uddin et al, 2021). The development of these infrastructures represents a global threat to bustards, which are among the world's most endangered birds (IUCN, 2022).…”

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“…Over the past years, a total of 65 ha of suitable habitat have already been lost to solar power plant, and 148 ha of suitable habitat will be further lost if proposed plants are developed. The development of solar energy plants typically carries the extension of the power lines, which have been found to be a main threat to bustard species worldwide (Silva et al 2023). Moreover, Abbasanta has been strongly afflicted by a locust plague over the past four years.…”