Wind farms on the Black Sea coast could endanger bat populations in
Eastern Europe

Date:
June 17, 2020
Source:
Forschungsverbund Berlin
Summary:
The Via Pontica, an important migration route for birds in Eastern
Europe, runs along the Black Sea coast of Romania and Bulgaria. Bats
also use this route. In this region, numerous wind farms have
been installed in recent years because of good wind conditions. A
research team has now demonstrated that this leads to high death
rates of migrating bats and potentially large declines even in
populations living in other countries.



FULL STORY ==========================================================================
The Via Pontica, an important migration route for birds in Eastern Europe,
runs along the Black Sea coast of Romania and Bulgaria. Bats also use
this route. In this region, numerous wind farms have been installed in
recent years because of good wind conditions, but there has been little implementation of the legally required measures for the protection of
bats. A Romanian research team cooperated with the Leibniz Institute for
Zoo and Wildlife Research (Leibniz- IZW) in Berlin to demonstrate that
this leads to high death rates of migrating bats and potentially large
declines even in populations living far away in other countries. The
scientists therefore recommend the widespread introduction of turn-off
times during the migration months, which -- as the team was able to
show in a local wind farm -- would massively decrease bat mortality yet
produce only a marginal loss in the energy production of the turbines.


==========================================================================
Over the past ten years, the coastal region west of the Black Sea
developed into a hotspot for wind energy production in Eastern
Europe. Favourable wind conditions make the operation of wind farms particularly profitable in this area. Moreover, the region is relatively sparsely populated, so conflicts between operators and residents are rare.

Because of the good wind conditions, there is also an important
migration route for numerous bird and bat species -- the so-called
Via Pontica, named after a historical Roman road connection. This area
should therefore particularly benefit from conservation measures such as carefully chosen turbine turn-off times in order to keep bat mortality to
a minimum. International agreements such as the EUROBATS agreement and
the European Union's Fauna Flora Habitat Directive do already provide
the legal framework for that. Currently, few protective measures have
been implemented and monitoring of the populations is limited or absent
in many regions in Eastern Europe. Accordingly, little is known about
the impact of wind farms on bat populations.

A Romanian research team in cooperation with the Leibniz-IZW investigated
bat fatalities in a local wind farm over a period of four years. The
wind farm, comprising twenty turbines, is located in the Romanian part
of the Dobruja, a historical coastal region between the Danube and the
Black Sea which forms the border between Romania and Bulgaria. Within
the four years, the scientists collected a total of 166 dead bats of 10 different species in the wind farm.

Carcasses of Nathusius' pipistrelle bats (Pipistrellus nathusii) and
common noctule bats (Nyctalus noctula) were particularly common. Since
many bats had open wounds and/or broken wing bones, they most likely
died as a result of direct collisions with rotating rotor blades. About
half as many animals died without direct collision from barotrauma,
which are commonly deadly lung injuries caused by huge differences in
air pressure close to the rotor blades.

Since the scientists conducted selective, punctual searches, the
scientists calculated the total loss of animals taking into account the
search pattern, search times and other factors such as the likely removal
of carcasses by foxes and stray dogs. According to this projection,
2,394 bats had died in this wind farm over the period of four years --
or in other words 30 bats per wind turbine and year or 14.2 bats per
megawatt and year. "This fatality rate is extremely high," says Dr
Christian Voigt, head of the Department of Evolutionary Ecology at the Leibniz-IZW. "For comparison: the highest fatality rates in Central Europe
or the USA are 10 bats per megawatt and year." A stable isotope analysis
of fur samples carried out at the Leibniz-IZW additionally revealed that
90 percent of bats came from distant regions in the north and northeast, including the Ukraine, Belarus and Russia.

"This has given us a clear picture of what happened," explains Christian
Voigt.

"The fatality rate is so high because the wind farm under investigation
is located in the middle of an important migration route for bats. Thus,
the wind farm does not only negatively affect local bats, but also
distant populations.

This makes it all the more important to take appropriate measures to
keep the fatality rate as low as possible, especially on such migration routes." The scientists have already shown at this site that this is relatively easy to achieve. During the summer months, when there is a
high level of bat migration, the operator -- in consultation with the scientists -- increased the threshold wind speed at which the turbines
start up (the cut-in speed) to 6.5 metres per second. As a result,
the fatality rate fell massively by 78 percent. "The energy production
of the wind farm decreased by only 0.35 percent per year, which is a
marginal loss for the operator," says Christian Voigt.

"This wind farm has a total capacity of 42 megawatts and is rather
small," the Leibniz-IZW scientist continues. "The wind farms throughout
the Dobruja region have a total capacity of at least 3,000 megawatts in operation. The total number of fatalities across this area could lead to
a long-term decline in local bat populations as well as those from large
parts of Eastern Europe. We therefore strongly recommend the widespread introduction of turn-off times and higher cut-in speeds. This will cost
the operators almost nothing and could make the Via Pontica once again
a largely safe flight path for bats."

========================================================================== Story Source: Materials provided by Forschungsverbund_Berlin. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Dragoş Ştefan Măntoiu, Kseniia Kravchenko, Linn
Sophia
Lehnert, Anton Vlaschenko, Oana Teodora Moldovan, Ionuţ
Cornel Mirea, Răzvan Cătălin Stanciu, Răzvan
Zaharia, Răzvan Popescu-Mirceni, Marius Costin Nistorescu,
Christian Claus Voigt. Wildlife and infrastructure: impact of wind
turbines on bats in the Black Sea coast region. European Journal
of Wildlife Research, 2020; 66 (3) DOI: 10.1007/s10344-020-01378-x ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200617150001.htm

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