Georg Nehls

BioConsult SH

PHAROS4MPAs A REVIEW OF SOLUTIONS TO AVOID AND MITIGATE ENVIRONMENTAL IMPACTS OF OFFSHORE WINDFARMS BioConsult SH report commissioned by WWF-France

The utilization of marine renewable energies such as offshore wind farming leads to globally expanding human activities in marine habitats. While knowledge on the responses to offshore wind farms and associated shipping traffic is accumulating now at a fast pace, it becomes important to assess the population impacts on species affected by those act...

Fossil and renewable energy production takes places in proximity to or within the Wadden Sea. The development of offshore wind energy in the Netherlands, Germany and Denmark has been rapid in the last decades and will even speed up in this decade. Up to now, more than 2,000 wind turbines have been built offshore in the North Sea within the territor...

In this study, the annual movements of a seabird species, the red-throated diver (Gavia stellata), were investigated in space and time. Between 2015 and 2017, 33 individuals were fitted with satellite transmitters at the German Bight (eastern North Sea). In addition, stable isotope analyses of feathers (δ13C) were used to identify staging areas dur...

Underwater noise immissions from construction vessels has been subject to intensive discussions in the planning phase of the Fehmarnbelt Fixed Link Project, because of a lack of national or international standards to measure and assess noise from shipping and dredging. The Fehmarnbelt-though one of the busiest waterways in Europe-holds important nu...

Birds migrating across offshore areas at night under certain weather conditions become attracted by artificial light and approach and even collide with vessels. In order to mitigate these effects during the construction of an Immersed Tunnel across the Fehmarnbelt between the Danish island of Lolland and the German island of Fehmarn, the German Pla...

The application of Very-High-Resolution (VHR) satellites to survey cetaceans has gained considerable tractionover the last decade. Large whale species in particular lend themselves to detection by VHR imagery of ~0.50mresolution or less. Processing of satellite images can be manually intensive, and consequently artificial intelligencemethods are un...

Expansion of offshore wind energy is vital for the reduction of CO2 emissions. However, offshore wind farms may negatively impact the environment without proper planning. Here we assess the robustness of the conclusions of earlier studies that the strictly protected red-throated diver, Gavia stellata, is strongly displaced from wind farms in the Ge...

The present study is based on a high-quality data set on the distribution and occurrence of divers in the German North Sea over the last 18 years and represents the most extensive data set currently available. For spring, 16 years of data were available (no data for 2006 and 2007), for winter, 17 years were available (2006 missing). This data set c...

Most cetacean species are wide-ranging and highly mobile, creating significant challenges for researchers by limiting the scope of data that can be collected and leaving large areas un-surveyed. Aerial surveys have proven an effective way to locate and study cetacean movements but are costly and limited in spatial extent. Here we present a semi-aut...

Marine habitats are nowadays strongly affected by human activities, while for many species the consequences of these impacts are still unclear. The red-throated diver (Gavia stellata) has been reported to be sensitive to ship traffic and other anthropogenic pressures and is consequently of high conservation concern. We studied red-throated divers i...

Seabird surveys have a long history and have been adapted for use in relation to wind farms. At first, boat-based and aerial observer surveys were used, but digital aerial survey techniques have been developed that offer enhancements in terms of speed of survey and, in some cases, cost, accuracy and safety. With specific stand-alone examples presen...

In Europe, the German Bight is one of the most important non-breeding areas for protected red-throated divers (Gavia stellata). It is unclear what attracts the birds to this area, especially as the food composition of seabirds outside the breeding season is notoriously difficult to study. To obtain information on prey species composition of red-thr...

The increasing demand for robust marine bird abundance and distribution assessments coupled with technological advances has led to the development of digital survey techniques for birds. Although digital surveys for bird monitoring are becoming a standard method in some countries, their strengths and weaknesses and comparability with traditional vi...

Marine mammals naturally occur in probably every offshore wind farm (OWF) worldwide. During construction, operation and decommissioning they are exposed to various pressures, of which the high levels of noise produced during pile driving of foundations into the seabed are the strongest, although other sources of noise including vessels may also hav...

We investigated the disturbance effects of offshore windfarm construction on harbour porpoises using acoustic porpoise monitoring data and noise measurements during construction of the first seven large-scale offshore wind farms in the German Bight between 2010 and 2013. At six wind farms active noise mitigation systems (NMS) were applied during mo...

Gas, oil and wind are energy sources exploited directly in or at least with effects to the Wadden Sea. In the Netherlands gas subtractions partially cause subsidence effects, with impact to an ecosystem under the influence of changing sea levels. The only active oil field in operation in the Wadden Sea is located in Schleswig-Holstein and is being...

In contrast to the outer North Sea, where mainly fish is targeted by large vessel or small scale fishery, the fisheries in and adjacent to the Wadden Sea concentrate on shrimps and mussels. Blue mussels are the most intensely exploited bivalve shellfish in the Dutch and German Wadden Sea, also by using cultures or mussel seed transfers. This fisher...

Dredging and marine sediment extraction both have been carried out during decades or even centuries in the Wadden Sea area. Due to high sedimentation rates in the Wadden Sea particularly dredging is an essential measure for maintaining harbours and shipping lanes. Between 2006 and 2013 an annual average of 36 million tons of sand was dredged within...

Anthropogenic developments in marine coastal zones potentially overlap with areas of conservation interest, including important areas for birds. Ideally, spatial patterns of species abundance should be considered at ecologically relevant spatial resolutions (high resolutions) to inform spatial planning and environmental assessments. Most planning s...

Aim of this part of the study was to investigate the flight behaviour of white-tailed sea eagles in the vicinity of existing wind farms by means of visual observations to determine especially the collision risk. Attempts were made to observe adult birds flying near wind turbines and to determine flight paths. Despite long watching series no substan...

By means of case studies, nature and extent of the effects of individuals lost due to wind turbines on establishment and survival of breeding territories and the breeding success of the white-tailed sea eagle are presented. By identifying individual colour rings and collection of moulted feathers, the individual breeding birds and the breeding succ...

In this chapter, distance from breeding site, spatial distribution of birds found dead and location of foraging waters of white-tailed sea eagles is put into context with existing wind turbines in Schleswig-Holstein in northern Germany. A general spatial separation of breeding sites of the white-tailed sea eagle and currently installed wind turbine...

Aim of the project was to investigate to what extent white-tailed sea eagles fly near wind turbines, to estimate the collision risks and to make proposals on how to reduce collisions.

This chapter summarizes the main results of the study and recommends measures to avoid collisions of birds of prey at wind turbines.

The behaviour of breeding Montagu’s harriers towards wind farms in Schleswig-Holstein in Northern Germany was investigated in a two years telemetry study. A total of 11 breeding birds were fitted with VHF transmitters. The home ranges varied between 340 and 1560 ha (kernel). Males had larger home ranges than females. Centres of flight activity (50%...

This book discusses the increase in number and capacity of wind farms in Germany and how this is affecting birds of prey. Several methods are used to study the behaviour of birds of prey in relation to wind farms, including telemetry data, field observations, and comparisons of turbine base areas. Special attention is given to the effects on differ...

First results of a study of red-throated diver, see www.divertracking.com for further information

Poster containing first results of a study of Red-throated Divers, see www.divertracking.com for details.

Collisions of birds with wind turbines are a focal point when discussing the implications of renewable energies on nature conservation. The project “Prognosis and assessment of collision risks of birds at wind turbines in northern Germany” (PROGRESS) focused on the extent and consequences of bird mortality at wind turbines. Collision victims were s...

Nocturnally migrating birds, particularly passerines, are known to be vulnerable to collision with manmade structures such as buildings, towers or offshore platforms, yet information with respect to wind farms is ambiguous. We recorded bird flight intensities using radar during autumn migration at four wind farms situated within a major migration f...

Effects of shipping traffic on the spatial and temporal distribution of seabirds in the Baltic Sea

The number of offshore wind farms in Europe and elsewhere has substantially increased in recent years. This rapid development has raised concerns about potential impacts on marine wildlife, particularly on seabirds, as these can be negatively affected through collision and displacement. While collision risk has been the focus of a number of studies...

Numerous studies based on passive acoustic monitoring by Porpoise Detectors (C-PODs) showed negative effects of pile driving by hydraulic hammers for the construction of offshore wind farms on harbour porpoise (Phocoena phocoena). We studied the efficiency of noise mitigation by two configurations of circular big bubble curtains (BBC1 & BBC2) regar...

During offshore wind farms construction, abundance in harbour porpoise (Phocoena phocoena) is known to be negatively affected. From 2011 to 2013, extensive passive acoustic monitoring was conducted during research projects accompanying the construction of two wind farms in the German North Sea. Using C-PODs, we studied the effect ranges of pile dri...

Kollisionen von Vögeln (und Fledermäusen) sind ein zentrales Konfliktfeld zwischen dem Ausbau der Windenergienutzung und dem Naturschutz. Obwohl mittlerweile eine hohe Anzahl von Studien zu diesem Bereich vorliegt, gibt es nur sehr wenige systematische Untersuchungen, in denen Kollisionsraten von Vögeln quantifiziert wurden. Dies erschwert die Bewe...

This study analyses the effects of the construction of eight offshore wind farms within the German North Sea between 2009 and 2013 on harbour porpoises (Phocoena phocoena). It combines porpoise monitoring data from passive acoustic monitoring using Porpoise Detectors (POD data 2010-2013) and aerial surveys (2009-2013) with data on noise levels and...

Acoustic monitoring of harbor porpoises (Phocoena phocoena L., 1758) indicated a strongly reduced disturbance by noise emitted by pile driving for offshore wind turbine foundations insulated by a big bubble curtain (BBC). This newly developed noise mitigation system was tested during construction of the offshore wind farm Borkum West II (North Sea)...

The construction of industrial offshore structures may lead to colonization by a variety of marine organisms resulting in locally enhanced biodiversity and biomass, which may then affect the habitat use and behavior of marine predators. For harbor porpoises high nocturnal echolocation activity was demonstrated near industrial structures and it was...

Unterwasser-Rammarbeiten zur Installation der Stahlfundamente von Offshore-Windenergieanlagen bewirken starke Schallemissionen, die zu Störungen oder Schädigungen von Meeressäugetieren führen können. Daher wird die Entwicklung von Schallminderungsmaßnahmen in Deutschland vorangetrieben. Im Projekt HYDROSCHALL-OFF BW II wurde das Schallschutzsystem...

The first German offshore windfarm (OWF) alpha ventus was constructed between September 2008 and August 2009 in the German Bight north of Borkum, North Sea. It comprises twelve offshore wind turbines on an area of 4 km² and is officially operating since April 2010. Using OWF alpha ventus as a test site, a major goal of this study, being part of pro...

Unterwasser-Rammarbeiten zur Installation der Stahlfundamente von Offshore-Windenergieanlagen bewirken starke Schallemissionen, die zu Störungen oder Schädigungen von Meeressäugetieren führen können. Daher wird die Entwicklung von Schallminderungsmaßnahmen in Deutschland vorangetrieben. Im Projekt HYDROSCHALL-OFF BW II wurde das Schallschutzsystem...

Common Scoter (Melanitta nigra) at the Schleswig-Holstein North Sea coast The Schleswig-Holstein North Sea coast has internatio- nal importance for Common Scoters as a wintering and moulting area. The Agency for Mining, Energy and Geo- logy (Landesamt für Bergbau, Energie und Geologie (LBEG)) gave the permission to extract sea sand to the west of...

Conservation decisions often rely on defining a reference status for habitats and species to enable targets to be set and progress measured. Long-lasting and continual anthropogenic impacts on habitats and species make the setting of undisturbed reference values such as diversity, distribution, population size or other ecological characteristics, d...

Underwater noise emissions from pile-driving during the construction of offshore wind farms can physically harm harbour porpoises in the vicinity of the construction site. In order to avoid injury to these animals, German legislation demands that pile-driving noise must not exceed 160dB re 1µ Pa (SEL) at 750 m distance from the sound source. Before...

Although seal scarers are widely used both to reduce economic losses at fish farms caused by seal predation and to reduce risks posed to marine mammals by offshore pile driving activities, the spatial extent of their deterrent effect on harbour porpoises is still largely unclear. However, this information is crucial to understanding the effects the...

Offshore pile driving, e. g. during wind farm construction, produces substantial noise emissions into the water column, which may harm marine mammals. Therefore, it is common practice to attempt to deter the mammals out of potential danger zones beforehand. Seal scarers are commonly used as a deterrent for harbour porpoises in spite of a lack of cl...

The Wadden Sea is situated along the coasts of Denmark, Germany, and The Netherlands, separated from the North Sea by small islands and sandbanks. Despite a range of anthropogenic pressures, including industrial activity, coastal development and resource exploitation, the Wadden Sea ecosystem is recognized as a biologically highly productive ecosys...

Rammarbeiten zur Installation der Stahlfundamente von Offshore-Windenergieanlagen bewirken hohe Schallemissionen, die je nach Entfernung zur Rammbaustelle Schädigungen oder Störungen von marinen Säugetieren führen können. Während dem Risiko einer direkten Schädigung von Meeressäugetieren durch Vergrämungsmaßnahmen und einer langsamen Erhöhung der R...

The world’s growing demand for sustainable and environmentally friendly energy has led a growing number of countries to explore the options for the installation of offshore wind farms. In particular, noise emissions during the construction phase, when, in many cases, steel foundations are driven into the seafloor, are expected to cause temporal avo...

Mortality of introduced Pacific oysters (Crassostrea gigas) was studied in the northern Wadden Sea in response to an ice winter. After a decade of mild winters, in January and February 2010, the first severe winter occurred since the Pacific oysters became dominant on former intertidal blue mussel (Mytilus edulis) beds in the North-Frisian Wadden S...

1. Offshore-Rammarbeiten zur Errichtung von Fundamenten für Offshore-Windenergieanlagen führen zu hohen Schallemissionen, die kurzzeitig eine großräumige Störung von marinen Säugetieren bewirken. 2. Die großen Wassertiefen der geplanten Offshore-Windparks bedingen insgesamt hohe konstruktive Anforderungen an Fundamente für große Windenergieanlagen,...