Mortality limits used in wind energy impact assessment underestimate impacts of wind farms on bird populations

Abstract

The consequences of bird mortality caused by collisions with wind turbines are increasingly receiving attention. So‐called acceptable mortality limits of populations, that is, those that assume that 1%–5% of additional mortality and the potential biological removal (PBR), provide seemingly clear‐cut methods for establishing the reduction in population viability. We examine how the application of these commonly used mortality limits could affect populations of the Common Starling, Black‐tailed Godwit, Marsh Harrier, Eurasian Spoonbill, White Stork, Common Tern, and White‐tailed Eagle using stochastic density‐independent and density‐dependent Leslie matrix models. Results show that population viability can be very sensitive to proportionally small increases in mortality. Rather than having a negligible effect, we found that a 1% additional mortality in postfledging cohorts of our studied populations resulted in a 2%–24% decrease in the population level after 10 years. Allowing a 5% mortality increase to existing mortality resulted in a 9%–77% reduction in the populations after 10 years. When the PBR method is used in the density‐dependent simulations, the proportional change in the resulting growth rate and carrying capacity was species‐independent and largely determined by the recovery factor (Fr). When Fr = 1, a value typically used for robust populations, additional mortality resulted in a 50%–55% reduction in the equilibrium density and the resulting growth rate. When Fr = 0.1, used for threatened populations, the reduction in the equilibrium density and growth rate was about 5%. Synthesis and applications. Our results show that by allowing a mortality increase from wind farm collisions according to both criteria, the population impacts of these collisions can still be severe. We propose a simple new method as an alternative that was able to estimate mortality impacts of age‐structured stochastic density‐dependent matrix models.

Wind power development in Eastern Kazakhstan threatens migration of eagles

“…Such species, and this includes all eagles, unlike species with lower survival rates and higher breeding performance, are generally unable to withstand excessive anthropogenic mortality (see, e.g., Sandercock et al, 2011). Modeling results based on the Leslie matrix model show that population viability can be very sensitive to proportionally small increases in mortality, and instead of a small effect it was found that an additional 1% mortality in the populations of several species studied, including the White-Tailed Eagle and the Marsh Harrier (Circus aeruginosus) resulted in population declines of 2-24% after 10 years, and assumption of a 5% increase in mortality over existing mortality resulted in population decline of 9-77% after 10 years (Schippers et al, 2020). This for species increasing their population size.…”

“…Many sources of anthropogenic mortality can also work together cumulatively to reduce populations in different locations throughout their life cycles (Loss et al, 2012;Schippers et al, 2020). For example, the number of breeding Griffon Vultures in the study territory in Spain decreased by 24%, adult survival by 30% and breeding performance by 35% as a result of the combined effects of feeding site closure and mortality at WPPs, but the population recovered once feeding was restored и др., 2018;Миллер и др., 2018;Fielding et al, 2021;Murgatroyd et al, 2021).…”

“…Такие виды, а к ним относятся все орлы, в отличие от видов с более низкой выживаемостью и более высокой плодовитостью, как правило не способны противостоять избыточной антропогенной смертности (см., например, Sandercock et al, 2011). Результаты моделирования на основе матричной модели Лесли показывают, что жизнеспособность популяции может быть очень чувствительной к пропорционально небольшому увеличению смертности и вместо незначительного эффекта обнаружилось, что дополнительная смертность на 1% в популяциях ряда изученных видов, в том числе орлана-белохвоста и болотного луня (Circus aeruginosus), привела к снижению численности на 2-24% через 10 лет, а допущение увеличения смертности на 5% по сравнению с существующей смертностью привело к снижению численности на 9-77% через 10 лет (Schippers et al, 2020) -и это для видов, увеличивающих численность.…”

“…Многие источники антропогенной смертности также могут кумулятивно работать вместе на сокращение численности популяций в разных местах на протяжении их жизненных циклов (Loss et al, 2012;Schippers et al, 2020). Например, численность гнездящихся белоголовых сипов на контрольной территории в Испании уменьшилась на 24%, выживаемость взрослых особей на 30% и плодовитость на 35% в результате совместного влияния закрытия подкормочных площадок и гибели на ВЭС, однако популяция восстановилась, как только подкормка была восстановлена, а самые проблемные ВЭС закрыты; исследование показало, что на продуктивность и выживаемость влияли в основном ВЭС, а нехватка пищи способствовала изменению поведения и удлиняло кормовые перемещения сипов, увеличивая риск столкновений (Martinez-Abrain et al, 2012).…”

Protecting the Local Landscape or Reducing Greenhouse Gas Emissions? A Study on Social Acceptance and Preferences towards the Installation of a Wind Farm

“…In the recent years, the rapid spread of wind farms worldwide as an answer to national commitments has entered into international agreements to tackle global warming, which have focused the attention of the public and academia on issues related to local negative impacts, such as landscape alterations; the production of noise; electromagnetic interferences; the subtraction of agricultural and natural space; and the risk of possible damages to flora and fauna, especially to migratory birds [1][2][3][4][5][6]. Although numerous sector studies and monitoring activities demonstrated the marginality of the majority of such impacts [7], the landscape degradation of wind farms is still considered a limiting factor, especially when wind farms take place in areas with distinctive landscape characteristics and identity place beliefs [8,9].…”