StUKplus Conference. Five Years of Ecological Research at alpha ventus - Challenges, Results and Perspectives October 2013, Berlin

Transcription

1 StUKplus Conference Five Years of Ecological Research at alpha ventus October 2013, Berlin Presentations and List of Participants

2 Bundesamt für Seeschifffahrt und Hydrographie (BSH)/ Federal Maritime and Hydrographic Agency Hamburg and Rostock All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission by the BSH. Cover photos courtesy of: alpha ventus/doti 2009 (photographer: Matthias Ibeler).

3 Part A: Presentations Developing Offshore Wind Energy: Tasks, Challenges and Demands A key milestone in German offshore wind energy: the alpha ventus offshore test site Jörg Kuhbier Offshore Wind Energy Foundation, Corresponding author: joerg.kuhbier@bbh-online.de In a February 2002 strategy paper, the German government adopted the ambitious and trailblazing goal of building 20,000 to 25,000 MW of offshore wind power capacity off the German coast by 2025 to The government and all parties in the German parliament adhere to that goal in principle to this day. But merely setting goals is not enough. Attaining them takes action, and the way there is often long, hard and full of obstacles. The development of offshore wind power has involved learning the hard way, and we are far from the end of the learning curve. alpha ventus is a key milestone marking the breakthrough for offshore wind power in. It is an important industrial and energy policy demonstration project, and numerous other offshore windfarms since built, planned or started in and elsewhere in Europe have benefited from the engineering and environmental experience and expertise gained in its construction and operation. The offshore wind farm Borkum West, the pioneer project later renamed alpha ventus, was approved by the Federal Maritime and Hydrographic Agency (BSH) in November The German Offshore Wind Energy Foundation, which was launched in 2005, used a 5 million grant from the German Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) to buy the rights to the wind farm in September A little over a year later, the foundation leased the rights out to a consortium formed by energy utilities EWE, Vattenfall and E.ON - the Deutsche Offshore-Testfeld und Infrastruktur GmbH (DOTI). Initial construction work began in autumn Under the strict German regulations on marine facilities, the interplay between offshore wind farms and the marine environment was a key issue for alpha ventus from the outset both during approval and in the ensuing planning, construction and operation phase. A major consideration was the impact on birdlife, marine fauna and life on the sea floor. The highest priority was and remains to minimise the impact on the natural environment. Page 3 of 43

4 Combining ecological research with the development of guidelines for environmental offshore monitoring (the StUKplus project) Nico Nolte & Anika Beiersdorf Federal Maritime and Hydrographic Agency (BSH), Corresponding author: In 2005, the development of the alpha ventus offshore wind farm was initiated. Being the nucleus for s offshore wind energy sector, the test site is a focal point for technical, ecological and social research comprised under the umbrella of the RAVE initiative. The ecological research at alpha ventus is bundled in the StUKplus research project, funded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU). This project supplements the mandatory ecological monitoring that has to be carried out by the wind farm operator according to BSH Standard for Environmental Impact Assessment, in short StUK. The StUKplus project sets a wider frame in size, scope and content than the ordinary StUK monitoring. In 2008, BSH was put in charge of coordinating the StUKplus project over a time period of almost six years - from May 2008 to March StUKplus is the most important German research project on potential environmental impacts related to offshore wind farms so far. During the extensive field research programme, novel observation methods and technologies such as aerial digital survey techniques and new bird migration radars were applied for the first time in German waters. The purpose of the ecological research programme was to gain a better understanding of possible environmental impacts of offshore wind farms and to evaluate the 2 nd update of the StUK standard (StUK3, BSH 2007), which was used for the first time in an offshore wind farm during construction and operation - in the alpha ventus offshore test site. The main research topics aimed to provide answers to the following questions: How do habitats change for benthic organisms and fish close to the foundations? How are these organisms influenced by the artificial reef structures? How do habitats change as a result of fisheries being excluded from the wind farm area? How do birds react to the rotating, illuminated wind turbines? Is there a risk of migratory birds colliding with the turbines at sea? Will resting birds avoid the wind farm area? What impacts will noise-intensive construction work have on marine mammals? Will they continue to use the wind farm as habitat and how can they be protected from noise? How do they react to operating noise? Page 4 of 43

5 Environmental impact of Belgian offshore wind farms: Learning from the past to optimise future monitoring programmes Steven Degraer, Robin Brabant, Delphine Coates, Ilse De Mesel, Jozefien Derweduwen, Marisa Di Marcantonio, Jan Haelters, Kris Hostens, Francis Kerckhof, Alain Norro, Jan Reubens, Bob Rumes, Eric Stienen, Jan Vanaverbeke, Sofie Vandendriessche, Nicolas Vanermen, Laurence Vigin & Magda Vincx Operational Directorate Natural Environment, Royal Belgian Institute of Natural Science, Belgium Corresponding author: In Europe, offshore wind farm projects are accompanied by obligatory environmental impact assessments, including baseline monitoring of the effects onto the marine ecosystem. Though very obvious to some extent, the effects of offshore wind farms are highly complex from an ecological perspective. While for example various monitoring programmes already demonstrated changes in community structure in e.g. benthic invertebrates, demersal fish and seabirds, it is less obvious how these effects are interlinked and what the underlying cause-effect relationships are. Unfortunately, baseline monitoring to which many, if not most monitoring programmes are restricted, only allows for an a posteriori quantification of the resultant effect, but not for a scientific identification and understanding of the underlying ecological processes. Such understanding however is indispensable when aiming at extrapolating knowledge for science-based mitigation actions in future wind farms. Key ecological processes behind the effects should therefore be identified and become subject of hypothesis-driven targeted monitoring and experimental studies. Such approach will facilitate a more time- and cost-efficient environmental impact assessment as well as an international collaboration aiming at an avoidance of duplication of research. The Belgian wind farm monitoring programme combines both baseline and targeted monitoring. The baseline monitoring ensures a continued vigilance and focuses on the distribution and community structure of marine mammals, seabirds, as well as soft and hard bottom bentho-pelagic and demersal fish, and benthic invertebrates. Targeted monitoring so far focused on e.g. the increased productivity of soft bottom benthos in relation to local organic enrichment, the trophic structure and habitat use of fish, and the harbour porpoise Phocoena phocoena redistribution due to construction noise propagation. On a yearly basis, the findings from both the baseline and targeted monitoring programme are discussed within a scientific committee composed only of those responsible for the scientific research, as to correct the monitoring programme in a scientifically-sound and, time- and cost-efficient manner, where needed. The programme hence ensures combining long-term continuity needed when monitoring, and short-term flexibility needed for a continuous programme optimisation. Page 5 of 43

6 Ocean Dynamics Oceanographic measurements at the alpha ventus offshore test site: the RAVE measurement service project Anja Schneehorst, Jens-Georg Fischer & Kai Herklotz Federal Maritime and Hydrographic Agency (BSH), Corresponding author: During the last decade, the demand for offshore wind energy utilisation has increased. The weather conditions in the North Sea ensure the power generation of large amounts of wind energy. Strong winds cause high and rough waves and can thus result in increased costs and high risks for the construction and operation of offshore wind farms. The RAVE measurement service project is part of the RAVE research initiative and coordinated by Federal Maritime and Hydrographic Agency (BSH). The project accompanied the construction and operation of alpha ventus in order to acquire a broad knowledge and experience base. The project was divided into several work packages covering a wide range of technical and scientific measurements. BSH collected particularly geological and oceanographic data to obtain reliable information about interactions between offshore facilities and the marine environment. Reliable information on the prevailing sea state, i.e. the wave heights, wave directions and wave periods, are essential for planning offshore logistics and for the optimisation of cost-intensive shipping and work operations. Such information is also essential for safety purposes. A range of sensors and measurement devices were mounted on wind turbines and in the test site for detailed investigation of oceanographic conditions. Temperature sensors, directional wave riders, video cameras and current sensors captured data to analyse interactions between the wind farm and the ocean. A central feature of the test site research was that the measurements were taken directly from the offshore structures. As many sensors as possible were mounted prior to erection of the turbines at sea to reduce the amount of difficult offshore installation work. In addition, BSH also coordinated and supported all measurements for the RAVE research initiative in the test site area. BSH conducted all maintenance and installation works, whenever sensors needed to be deployed or recovered for any of the participating RAVE research partners. The following presentation is intended to give the audience an impression of the different measurements made at the alpha ventus test site during the last five years of construction and operation. Page 6 of 43

7 Geological research at alpha ventus: the spatiotemporal development of scours Bettina Kühn & Manfred Zeiler Federal Maritime and Hydrographic Agency (BSH), Corresponding author: Different parameters, such as current speed and direction, sediment types or the foundation design itself, control the sediment transport underneath the foundation structures and may cause scouring around the piles of the foundations. There is still lack of knowledge regarding scouring and the relocation of the eroded sediment around pile-driven foundations. The depth and the extent of a scour can influence the stability of a construction. At the beginning of the RAVE research programme, no in situ-measurements were available for the German North Sea. To rectify this situation, the variability of the seabed morphology at the alpha ventus test site has been investigated and a geological subsurface model for the upper five meters of the seabed has been developed. The relevant parameters and their interactions had to be analysed. A combination of fixed single-beam echosounders and full-coverage multi-beam echosounders was employed in order to obtain a spatiotemporal dataset of the scour dynamics at the alpha ventus wind farm. In order to monitor the scour depths and processes, 33 single-beam echosounders were attached to the tripod (AV7) and the jacket foundation (AV4) before the installation of the turbines at sea. Since 2009, the single-beam echosounders have been recording data in high temporal resolution every 10 minutes. These data reveal that scouring is still occurring although the erosion rate decreased substantially after the first five months. In addition to the single-beam echosounders, which only provide point measurements, multibeam sonar surveys have been performed every spring and autumn since The results of the surveys confirm the data of the fixed single-beam echosounders. Furthermore, the individual scours around the piles show a tendency to combine to form one scour beneath the substructure by lateral growth. The results from both locations reveal the different scouring effects at tripod and jacket foundations. Additionally, the tidal signal shows a strong correlation between the current speed and the direction of movement along the sediment pathway. Page 7 of 43

8 On the effect of offshore wind farms on ocean dynamics Elke Ludewig 1,2 & Thomas Pohlmann 2 1 International Max-Planck Research School for Maritime Affairs, 2 Institute of Oceanography of the University of Hamburg, Corresponding author: elke.ludewig@zmaw.de As a result of the increased demand for renewable energy, offshore wind farms have become increasingly popular, especially since over sea yields are larger and more reliable than over land. In this context, has adopted the position of a pioneering nation due to its national offshore wind energy programme comprising an intensified construction of wind turbines in the North and Baltic Seas. Against this background, it becomes particularly urgent to enquire whether and to what extent such expansion affects our oceans and local climates. As known from the relevant literature, offshore wind farms generate a so-called wake-effect, which impacts atmosphere s boundary layer, locally modifies the wind characteristics and, in turn, affects ocean dynamics. To study the entire complex in more detail, our investigation utilised model simulations and measurements. Among the models used are the atmosphere model METRAS (MEsoscaleTRAnsport and Stream model), which considers changes in the atmosphere due to wind turbines, and the ocean model HAMSOM (HAMburg Shelf Ocean Model), which is forced by METRAS results and provides information on hydrodynamic and hydrographical changes evoked by wind turbines. In collaboration with the Federal Maritime and Hydrographic Agency (BSH), model results were validated by means of measurements taken in May 2013 around the alpha ventus offshore wind farm. Our model simulations include a sensitivity study and more realistic simulations of s Exclusive Economic Zone (EEZ) to identify, on the one hand, changes in the physical oceanic processes induced by offshore wind farms, and on the other hand, to estimate possible future integrated changes of the marine system based on the offshore construction plan for The main results of our studies show significant dynamic changes including an evolving dipole structure of the sea surface elevation around offshore wind farms (magnitude of several mm) and up- and downwelling cells with a horizontal extension of approximately 30 x 30 km, spanning the entire ocean depth. The connected vertical velocities reach magnitudes of 10-5 m/s, or around 3 to 4 m/d, respectively. In turn, these vertical motions induce changes in stratification of temperature and salinity, which result in a maximum excursion of the thermocline by as much as 10 m. Hence, it can be concluded that offshore wind farms cause an intensified vertical mixing in the ocean, which may result in a fundamental change in the North Sea ecosystem. Model results and measurements show a reasonable agreement, which supports the principle validity of our model approach. Page 8 of 43

9 Benthos and Fish Development of a soft bottom community within an offshore wind farm results after three year operation of alpha ventus Andreas Schmidt 1, Lars Gutow 2, Katharina Teschke 2, Stephanie Preuß 1, Manuela Gusky 2, Stefanie Breyer 1, Rita Fürst 1 & Regine Bönsch 1 1 Institute of Applied Ecology GmbH (IfAÖ), 2 Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Corresponding author: a.schmidt@ifaoe.de Many benthic invertebrate species persist in complex interactions with their biotic and abiotic environment, and thereby providing important ecosystem goods and services. In the first German offshore wind farm alpha ventus, which has been in operation since 2009, benthic data were sampled continuously from 2008 (baseline survey) until 2012 (third year of operation) in the spring and autumn of each year. Investigations of the macrofauna communities (in- and epifauna) have been conducted according to the Standard Investigation of the Impacts of Offshore Wind Turbines on the Marine Environment (StUK3, BSH 2007) issued by the Federal Maritime and Hydrographic Agency (BSH). The standard is based on the most widely used environmental impact assessment design, the BACI design (Before After Control Impact). During the investigations about 200 benthos species were detected in the sandy sediments of the alpha ventus wind farm. The species community belongs to the typical Tellina fabula association of the North Sea. The results show alterations both over time and between the wind farm and the reference area for the benthic community as well as for the sediment parameters. The temporal and spatial variation is evident in e.g. the total abundance, which was different between the wind farm and the reference area. As to the epifauna, the abundance was higher in the reference area than in the wind farm area at the end of the study period. In accordance with the principles of environmental impact assessment using the BACI design, the different temporal variations of various community descriptors in the wind farm and in the reference area indicate different environmental conditions in those two areas, which might have been the result of the construction and operation of the turbines in the alpha ventus area. However, the results have to be interpreted carefully. Hence, the results of the study will be used to identify possible weaknesses in the underlying methods; and they additionally provide a valuable basis for impact assessments for future offshore wind farm projects. Page 9 of 43

10 Effects of offshore wind turbine foundations on mobile demersal megafauna and pelagic fish research at the alpha ventus offshore wind farm Roland Krone & Sören Krägefsky Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Corresponding author: Several thousand planned wind turbine foundations will substantially increase the amount of habitat available for hard-bottom associated mobile demersal megafauna (MDM) in the German Bight (North Sea). To assess the effect of the large-scale habitat creation on MDMstocks, the foundations (tripods and jackets) of the small-scale alpha ventus wind farm were systematically scrutinized by diving. Two years after construction, hard-bottom species already reached 100 fold higher abundances at the foundations than at autochthonous soft sediments. Large concentrations of pouting (Trisopterus luscus) and the Atlantic horse mackerel (Trachurus trachurus) were detected at the foundations. The brown crab (Cancer pagurus) reached abundances of 2,300 individuals at single foundations, whereas it reached only 29 individuals in the reference areas. The uppermost parts of the foundation structures were densely and exclusively colonised by young C. pagurus they potentially function as nursery grounds. The stocks of predatory hard bottom species could multiply with the installation of numerous offshore wind farm foundations in the North Sea. The settlement of MDM at the foundations of wind farms should be considered when assessing offshore wind farm reef effects and possible environmental impacts. The effects of alpha ventus on pelagic fish were investigated by hydroacoustic surveys, by sampling with net catches and by fish stomach content analysis. A relative decline in abundance of pelagic fish in alpha ventus during the construction phase suggests scaring effects on fish caused by pile driving and other construction related activities. Stomach content analysis shows that hard substrate associated organisms were an insignificant food component of Atlantic mackerel (Scomber scombrus) and T. trachurus captured within the alpha ventus wind farm. Mackerels caught within the wind farm showed a significantly reduced degree of stomach fullness compared to mackerels caught outside the wind farm, suggesting disturbed food gathering behaviour or differences in food composition and distribution within the wind farm area. Page 10 of 43

11 Large-scale studies on benthos in the German Bight the value of combining scientific data and data from offshore wind farm monitoring Jennifer Dannheim, Jan Holstein, Manuela Gusky & Lars Gutow Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Corresponding author: In, offshore wind farm projects are accompanied by obligatory Environmental Impact Assessments (EIA) studies. The mandatory monitoring standard Investigation of the Impacts of Offshore Wind Turbines on the Marine Environment (StUK3, BSH 2007) prescribes extensive investigations of soft-bottom benthos and benthic fouling assemblages on the wind turbine foundations. The data collected in the implementation of EIAs and scientific projects in the last five years were consolidated, harmonised and subjected to quality control before being entered into a database. To date, the database contains information on marine benthos with > 250,000 taxonomic entries relating to > 9,000 stations. This unique database serves as the basis for large-scale benthic ecosystem analysis. Numerous ecosystem goods and services, such as marine biodiversity, long-term carbon storage and natural resources (e.g. for fish, birds, mammals and finally humans), are intimately linked to the benthic system. Maintenance of the benthic system at a healthy ecological status is thus of particular interest. At the scale of the German Exclusive Economic Zone (EEZ), analyses are performed to identify benthic spatial patterns, to revise benthic associations, as required, and to determine the main drivers for species distribution or assemblages. Current efforts are being made to quantitatively model benthic species distributions in the German EEZ on a transnational scale. Finally, functionally sensible areas and important geographic sites that are of public concern regarding ecosystem services and goods are to be identified. This data will be used to provide evaluation criteria for identifying sensible areas in the context of licensing procedures of offshore wind farms and marine spatial planning. Furthermore, we strive to estimate species or group specific natural corridors of variation to discriminate anthropogenic effects from natural background variability in the future. Study outcomes (e.g. in terms of maps) will be made public via the internet in order to provide stakeholders, e.g. authorities and scientific institutions, with scientific advice. Page 11 of 43

12 The turbine focus: benthic fauna on and around offshore wind farm constructions Lars Gutow 1, Katharina Teschke 1, Manuela Gusky 1 Roland Krone 1 & Andreas Schmidt 2 1 Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 2 Institute of Applied Ecology GmbH (IfAÖ), Corresponding author: lars.gutow@awi.de Artificial hard substrata in the marine environment have substantial influence on nearby sediments and the inhabiting benthic communities. Scouring of the seafloor and import of biomass from the fouling assemblage on the solid underwater structure induce physical and chemical changes of the benthic environment. The spatial extent of these changes depend on the size and shape of the underwater structure and on the local hydrographic conditions and is yet unknown for offshore wind turbines. After construction of the turbine foundations at alpha ventus in 2009, species richness and biomass of the fouling assemblage increased steadily reaching a biomass of more than 20 kg m -2 in the shallow subtidal mussel accumulation. A random walk particle drift model was established to estimate the distribution of biomass released from the fouling assemblage on the surrounding sediments. The results predict the sedimentation of biomass in distances of up to 4 km from a wind turbine. Therefore, a turbine related monitoring was initiated to investigate potential effects of the organic enrichment of the sediment on the composition of the benthic infaunal community. The monitoring covered the entire distance between two turbines with spaces between sampling stations of 100 m. After the construction of the turbines and two years of wind farm operation no changes in the distribution of single species and in the structure of the entire infaunal community were evident that could be related to the presence of the turbines. Furthermore, no sign of recovery of the benthos from bottom trawling was evident after fisheries had been banned from the wind farm area for three years. We conclude that the spatial resolution of the monitoring was likely inappropriate to identify effects induced by the turbines. Additionally, the benthos requires longer time to recover from decades of continuous bottom trawling. Page 12 of 43

13 Seabirds Effects of alpha ventus on distribution patterns, behaviour and flight heights of seabirds Stefan Garthe, Bettina Mendel, Jana Kotzerka & Julia Sommerfeld Research and Technology Centre (FTZ), University of Kiel, Corresponding author: The number of offshore wind farms in the German Bight (North Sea) is increasing rapidly. To date, 33 wind farms have been licensed, and many more, proposed (as of September 2013). Eight wind farms are currently under construction, the first (and until very recently the only one) was completed in April Two seabird projects were implemented in the framework of StUKplus. In the TESTBIRD project, the impact of alpha ventus on seabirds was examined during the operational period of the offshore wind farm. In a second project, data on seabird distributions from all Environmental Impact Assessments (EIA) studies conducted prior to the construction of offshore wind farms, during the construction period, and during the operational periods were combined with the long-time dataset from various research projects conducted by the Research and Technology Centre (FTZ) in Büsum. This presentation is based on data from the combined database (EIAs and FTZ studies) for the alpha ventus wind farm and large-scale monitoring and research surveys. We used this database to investigate seabird abundance and distribution in relation to alpha ventus. This includes possible differences in seabird densities between the pre- and post-construction periods. Finally, using the TESTBIRD project as a basis, data on behaviour and flight heights of selected seabird species are shown. Data on seabird distribution for the periods before and after construction of alpha ventus show substantial differences, primarily as declines in the overall abundances of most seabird species. Most species avoid the wind farm site and its direct vicinity. Behavioural observations show that at least some seabird species (most prominent among them, the lesser black-backed gull Larus fuscus) use the wind farm site as a foraging area, though in lower numbers than before construction. Flight height measurements from a reference area suggest low to high overlap between flight heights of seabirds and the operational height of alpha ventus, with large gulls being exposed to the highest collision risks. Such information may become relevant when comparing flight heights inside and outside wind farms (our sample size is currently still too small) and as input for collision risk models. Page 13 of 43

14 Is the distribution and abundance of waterbirds altered in and around Danish offshore wind farms? Ib Krag Petersen Department of Bioscience, Aarhus University, Denmark Corresponding author: In 1999 a Danish demonstration programme concerning offshore wind farms was initiated. The aim was to evaluate environmental and technical aspects in relation to introducing these new structures at sea. Aarhus University was involved in ornithological investigations in that respect. Monitoring programmes for Horns Rev 1 and the Nysted offshore wind farms were initiated, and after the erection of the turbines post-construction monitoring programmes were initiated. Data from these investigations will be touched upon. At Nysted offshore wind farm common eiders (Somateria mollissima) avoided flying through the wind farm to a large extent and long-tailed ducks (Clangula hyemalis) utilised the area of the wind farm significantly less after the appearance of the wind farm than before. At Horns Rev 1 it seemed that red-throated diver (Gavia stellata) avoided utilising the area of the wind farm and the near surroundings. Common scoters (Melanitta nigra) initially showed signs of avoidance, but in the spring of 2007 birds were seen in densities within the Horns Rev 1 wind farm that was equal to the densities found around the wind farm. Very recent findings from Horns Rev 2 indicate that this have to be re-considered. Later development at Rødsand 2 and Horns Rev 2 opens a discussion about the aspect of cumulative effects. These discussions involve also considerations about what the consequences are for displaced birds in an area. Modeled approaches are required to assess these issues. Monitoring of marine birds has switched from aerial surveys conducted by human observers to surveys using digital cameras. Aarhus University have developed a survey method using very high end airborne cameras and object-based semi-automated pattern recognition principles to extract birds from the images. This development will be shortly mentioned too. Page 14 of 43

15 Lessons learnt from offshore wind farms in the Netherlands: SOME habitat loss for SOME seabirds Mardik Leopold Wageningen-IMARES, Netherlands Corresponding author: When the first offshore wind farms were planned seabirds were considered to be at considerable risk of losing part of their at-sea habitat. Unlike birds living in forests, they would be unfamiliar with large object above ground level and these would scare them off. After several years of on-site studies, we have learnt that indeed some birds shy away from offshore wind farms, but that at the same time, others are attracted to them, or simply ignore their presence. Furthermore, avoidance behaviour seems to be dependent on wind farm design: the size and/or configurations of the turbines in the wind farm. Studying seabird avoidance behaviour is by no means a simple matter. Seabird distribution patterns are notoriously patchy and often show wind-farm sized areas where numbers are low. Moreover, many seabirds occur in low numbers around a given wind farm and their whereabouts are not only influenced by the presence of the wind farm studied, but by many factors: shipping, discarding fishing vessels, natural variation in food availability or gradients in abiotic factors and even other wind farms in the vicinity. One should thus carefully design survey layouts to study possible effects of a single wind farm on seabird densities. Comparing a single impact area (wind farm) to a single reference area has the risk of not comparing likes with likes: The reference area may differ in other respects than wind farm presence from the impact area, or local seabird densities differ, just by chance given the patchiness of their distributions. The power of such comparative studies is usually low but can be improved by a careful study design and proper analysis of the data. In general, it is cost-effective to put most study effort into the birds that really matter and into times of the year when these are abundantly present. Such an approach would be preferable over standard year-round surveys, which waste a lot of time and effort on surveys that will never produce meaningful results. Page 15 of 43

16 Bird and Bat Migration Results, conclusions and perspectives from 10 years of offshore bird migration research in the German Bight Reinhold Hill, Ralf Aumüller, Karin Boos, Sabine Freienstein & Katrin Hill Avitec Research GbR, Corresponding author: The number of offshore wind farms in the German Bight is currently increasing. Concurrently, concern about their possible effects on migrating birds is also increasing. The German Bight is located at the centre of the East Atlantic flyway, which is passed twice a year by millions of migratory birds on their recurrent journeys between their breeding and wintering areas. During the last decade, data on bird migration has been collected comprehensively on the FINO1 research platform within the framework of ecological research projects on behalf of the Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) as well as of Environmental Impact Assessments (EIA) studies in the scope of StUK3 (BSH 2007). Some species migrate during the day, but the majority of the species are nocturnal migrants. They are probably affected by wind turbines in different ways: Diurnal migrants might be more likely to avoid wind farm areas than to collide with the turbines. Conversely, nocturnal migrants are likely to be attracted to the obstruction lights of the turbines and consequently experience a higher collision risk. Both, diurnal and nocturnal migrants are affected strongly by weather variables, such as wind, visibility or precipitation. To investigate the above mentioned challenges, a number of automated techniques, such as radar, different camera systems and recording of species-specific flight calls, have been used on FINO1 since its construction in Collected data offer insights into the migration course including bird densities and species affiliation irrespectively of variability among specific years. During the day, we introduced an advancement of visual observations that allow for directly observing different responses of numerous species or species groups to offshore wind farms. From standardised viewing directions alternating towards and away from the wind farm, it can be concluded that some species groups avoid the wind farm, whereas others are attracted to it. Currently, we are attempting to determine species-specific thresholds for the occurrence of distance reactions to offshore wind farms. The long-term data allow comparisons before and after construction of the proximal alpha ventus wind farm, and changes in bird migration patterns are presented in this presentation. Moreover, results for species-specific reactions to the alpha ventus wind farm from visual observations are presented. Another research platform, FINO3, was constructed in 2009 and provides similar remote sensing techniques for measuring bird migration and thus allows comparisons between different locations within the German Bight. The differences between the results from FINO1 and from FINO3 are presented exemplarily. Page 16 of 43

17 Avian migration over offshore wind farms: How many birds will get stuck plus the tools you need to find out Timothy Coppack, Tobias Dittmann & Axel Schulz Institute of Applied Ecology GmbH (IfAÖ), Corresponding author: Large bodies of water represent significant ecological barriers for migrating land birds, often resulting in impressive accumulations of migrants along coastlines a phenomenon referred to by ornithologists as mass migration (as opposed to mass accumulations caused by artificial light). Bird observatories and ringing stations are therefore classically situated on coastal peninsulas or islands, with the consequence that most of our knowledge of migration rates and patterns is based on what is observed at these hot spots. Before ornithological research on the research platform FINO1 (and within the alpha ventus wind farm) in the German Bight was initiated, little was known about the occurrence and performance of migrants at sea, and answering fundamental questions related to wind farming was limited by a lack of suitable detection methods and continuous monitoring information from operational wind farms. It is well established that the vast majority of migrants fly solitarily and nocturnally. Furthermore, migration appears to take place during a comparatively low number of nights when certain favourable meteorological conditions coincide. To assess the collision risks for migrating birds, their occurrence has to be quantified within the rotor-swept zone and set into relation to overall migration rates. The purpose-built radar BirdScan installed on FINO1 next to alpha ventus has been continuously recording migration traffic rates since The design of this ongoing survey includes alternating measurements within and outside the wind farm, enabling the assessment of avoidance rates and phototactic aggregations of migrants under various weather situations. The presence and performance of birds within the rotor-swept zone can be further elucidated with the motion-controlled infrared camera system VARS that is mounted onto the nacelle of a representative wind turbine and which has been running continuously over three years. Results combining data collected by radar on FINO1 and night-vision cameras on the wind turbine show that birds may be attracted to wind farms. We analysed such accumulation events, which have been detected at various functional levels using a multi-scale approach. The attraction of birds by artificial light obviously plays a crucial role, profoundly influencing the risk of collision for nocturnal migrants, in particular if attraction occurs when overall migration density is high. At a smaller spatial scale, however, such attraction effects may be offset to some extent by micro-avoidance in response to rotor movements. To substantiate this hypothesis, long-term continuous surveys are urgently needed to be able to detect migratory bouts and accumulations of migrants associated with elevated collision risk. Final results will allow testing the effectiveness of the currently recommended operational controls, i.e., shutting down wind turbines during peak migratory periods. Page 17 of 43

18 Comparing baseline and construction studies in the BARD Offshore 1 wind farm: aspects of bird migration Helmut Wendeln, Gottfried Walter & Dieter Todeskino IBL Umweltplanung GmbH, Corresponding author: wendeln@ibl-umweltplanung.de Bird migration is an important issue in the approval procedure of offshore wind farms in. A threat of bird migration can be a reason to refuse a windfarm project (Section 5 (6) (2), SeeAnlV). According to the Standard for Environmental Impact Assessments (StUK3, BSH 2007) three years of baseline monitoring for the BARD Offshore 1 wind farm in the German North Sea were performed (2004/2005/2008), which was followed by a monitoring of three years construction period ( ). Methods applied comprised visual observations and radar detection (vertically and horizontal rotating ship radar, 25 kw power). Both methods were applied from vessels. Additionally, vertically rotating ship radar was operated on the transformer substation BARD1 in the second and third year of construction to investigate evasive and attraction movements within the wind farm. In the presentation we show comparative results between baseline and construction period monitoring. These results refer to possible changes in number and composition of species (visual observations) as well as to a comparison of migration volumes and flight altitudes based on radar data. Next to the comparison of periods, we also present results on possible effects of the construction activities on migrating birds Page 18 of 43

19 Pilot study on bat migration on the German Baltic Sea Antje Seebens 1,2, Angelika Fuß 1,2, Peter Allgeyer 1,2, Henrik Pommeranz 1,2, Michael Göttsche 1, Matthias Göttsche 1, Mathias Mähler³, Hinrich Matthes 1,2, Christoph Paatsch 1,2 & Lothar Bach 1 1 Working Group Bat Migration over the Baltic Sea, ² Expert Committee for Bat Conservation and Research of the Nature and Biodiversity Conservation, Union Mecklenburg-Western Pomerania, ³ Jordsand Association for the Protection of Seabirds and Nature, Corresponding author: info@batmigration.de The fact that bats fly over the Baltic Sea during migration and foraging and that they are attracted by offshore wind turbines and might thus collide with the turbines has been shown in studies conducted along the Scandinavian Baltic coast. In the German Baltic Sea, the construction of approximately wind turbines is planned. Reliable and comparable data on bat occurrence and phenology is urgently needed to allow bats to be included in the wind farm licensing procedure. A pilot study was therefore started at the German Baltic coast of Mecklenburg-Western Pomerania to contribute to the currently rather basic knowledge on bat migration over the southwestern Baltic Sea. An acoustic survey was conducted with time expansion detectors (Petersson D 500x, Avisoft Ultrasound Gate, EcoObs Batcorder) on the Riff Rosenort research platform (situated 2,2 km offshore), on the Greifswaler Oie island (situated 12 km north of the island of Usedom) and additionally on a ferry crossing the southwestern Baltic Sea. Migratory bat species such as nathusius' pipistrelle Pipistrellus nathusii and common noctule Nyctalus noctula were detected in significant numbers during the migration period. Calls of common pipistrelle Pipistrellus pipistrellus were also recorded in large numbers. Furthermore we found the two species leather-winged bat Vespertilio murinus and soprano pipistrelle Pipistrellus pygmaeus. Numbers of bats detected on the ferry far out on the Baltic Sea were much lower. In addition to specifying the species-specific amount and phenology of bat activity offshore, further studies should concentrate on those factors that might predict offshore bat migration peaks. Knowledge of these factors, which would reliably predict periods of possible high fatality rates, is essential to protect migrating bats from offshore-wind-energy-related mortality by implementing turn-off-times of turbines a possible solution that fulfils the requirements for both bat conservation and renewable energy production. Page 19 of 43

20 Marine Mammals I Harbour porpoises in the southern North Sea analysis of potential influences of alpha ventus in the context of general distribution trends Anita Gilles 1, Michael Dähne 1, Verena Peschko 1, Sven Adler 2, Katrin Ronnenberg 1 & Ursula Siebert 1 1 Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, 2 Swedish University of Agricultural Sciences, Sweden Corresponding author: anita.gilles@tiho-hannover.de Before, during and after the construction of alpha ventus a comprehensive monitoring was carried out using visual line transect sampling along with continuous static acoustic monitoring to investigate possible short- and long-term impacts of alpha ventus on harbour porpoises. The seasonal and spatial distribution of porpoises were analysed by dedicated aerial surveys in a study area of almost 11,000 km 2 while the habitat use and behaviour were investigated with 12 echolocation loggers. We showed that the effect of the short-term construction period had an impact over large distances as detection rates decreased in less than 10.8 km and increased in larger distances to alpha ventus, suggesting that porpoises were displaced towards these positions. Here, we will focus on data of the operating period and place results in the context of general distribution trends. The operation period most likely has a small spatial scale impact where effects could either be attributable to noise or to the creation of artificial reefs that impact on prey species. To validate noise effects we modelled the C-POD data collected in 2011 constructing one model with data from periods when turbines were switched off and another from periods when turbines were switched on. The analysis shows that while very close range effects may occur, they most probably do not have a larger scale effect on porpoise detection rates. A Bayesian trend analysis revealed an increase of porpoise occurrence in the southern German North Sea between 2002 and This increase has been observed since 2005, i.e. before the installation of alpha ventus. It is, thus, unlikely that this small-scale wind farm has an impact on densities over the large monitored area. The effects documented at alpha ventus should now be set into perspective with cumulative impacts of a larger number of wind farms being constructed quasisimultaneously. Page 20 of 43

21 Behavioural response of harbour porpoises to pile driving on a temporal and spatial scale at BARD Offshore 1 Veronika Wahl, Alexander Braasch, Michael Joost, Christian Ketzer, Andreas Michalik & Dieter Todeskino IBL Umweltplanung GmbH, Corresponding author: wahl@ibl-umweltplanung.de During the construction period (April 2010 until March 2013) of the German offshore wind farm BARD Offshore 1, we investigated temporal and spatial patterns of behavioural responses of harbour porpoises (Phocoena phocoena) to pile driving. As a measure of abundance, harbour porpoise acoustical activity was monitored using passive acoustic monitoring devices (C-PODs). During the construction period C-PODs were deployed in a gradient sampling design ( mobile C-PODs) in distances of 750 m, 2,000 m, 5,000 m and 8,000 m with respect to the respective pile driving site. The obtained dataset was complemented with long-term measurements using data from three C-POD stations located in the surroundings of the construction site (up to a distance of 26 km). We analysed waiting times (pauses between continuous porpoise-click-sequences) to assess the magnitude of the pile driving effect. Additionally, porpoise acoustical activity per hour in relation to time after pile driving was evaluated using generalized additive models (GAM) to estimate the possible duration of the effect. Our results indicate that harbour porpoises left the immediate vicinity of the wind farm during pile driving as the acoustical activity was reduced by almost 100 %. After pile driving, the acoustical activity stayed below normal levels for on average 20 h. Prolonged waiting times after pile driving were detectable up to a distance of 8 km; the magnitude of the effect gradually decreased with increasing distance. Beyond a distance of 8 km no consistent pattern was observable, although there is strong indication that the behavioural response of harbour porpoises to pile driving may extend to distances greater than 20 km. Page 21 of 43

22 Lesson learned: effects of pile driving on harbour porpoises for three offshore wind farms in the German Bight Ansgar Diederichs, Miriam Brandt, Armin Rose, Caroline Höschle & Georg Nehls BioConsult SH GmbH, Corresponding author: Pile driving during offshore wind farm construction goes along with considerable noise emissions that potentially harm harbour porpoises (Phocoena phocoena L., 1758) in the vicinity of the sound source and may displace the animals over large distances. Knowledge about the scale of such effects grew considerably during the last few years. Three aligned studies at Horns Rev II, alpha ventus, and Borkum West II uncovered a close relationship between the levels of underwater noise caused by pile driving and the intensity of spatial and temporal displacement effects on harbour porpoises. Great efforts were made with all these studies towards gaining statistically robust data sets under complex conditions. Horns Rev II offshore wind farm proved spatial displacement effects up to 18 km distance from the construction site, following a gradient with more animals being affected with decreasing distance. The alpha ventus offshore wind farm confirmed these findings, even though a complex seasonal pattern of porpoises in the wind farm area impaired analyses. In addition, it was shown that besides the noise level also pile driving duration played an important role regarding the magnitude of the displacement effect. During the construction of the Borkum West II offshore wind farm, displacement effects were for the first time shown to be directly related to noise levels measured at different positions in and outside the wind farm area. These results were consistent with former findings and approved that displacement of harbour porpoises during pile driving was in close relation with sound exposure level and followed a gradient of more animals being affected at higher noise levels. These results clearly demonstrate that noise reduction has the potential to be a major benefit for a threatened species listed in Annexes II and IV of the EU Habitats Directive. Page 22 of 43

23 Habitat modelling of porpoises in support for marine spatial planning in the German Bight Henrik Skov 1, Stefan Heinänen 1, Dennis A. Hansen 1, Florian Ladage 2, Bastian Schlenz 2, Ramūnas Žydelis 1 & Frank Thomsen 1 1 DHI, Denmark 2 DHI-WASY, Corresponding author: hsk@dhigroup.com The harbour porpoise habitat modelling project has been launched to consolidate the existing data from offshore wind farm projects on the distribution and abundance of the harbour porpoise Phocoena phocoena in the German Bight by means of long-term analysis and modelling. The objective is to achieve a unified understanding of the environmental factors governing the distribution of the species and to determine good porpoise habitats in this region. Although this is an ongoing project, the results are expected to allow prediction of seasonal distributions at fine spatial resolution for the 10 year investigation period. In this context, estimates of the persistence of the distribution of harbour porpoises during the summer season are given; they are based on linkages between observations from aerial surveys and oceanographic conditions and pressures. This approach requires coherent oceanographic and pressure data for the entire German Bight, which is based on hydrodynamic and noise models designed for this purpose. In total, 139 aerial summer surveys were included in the analysis. According to the model, areas of high and very high persistence of harbour porpoises are found in three regions; one in the outer German Bight stretching northwest from Helgoland, one off the East Frisian islands and one just north of the Dogger Bank. In total, these areas represent less than 20 % of the total area of the German Exclusive Economic Zone (EEZ). In terms of oceanographic and pressure characteristics, these areas can be described as consisting of deep areas with fairly coarse surface sediments, intermediate west and east-flowing current velocities, weak northerly currents, relatively low sound levels and increasing current speed. The model has good explanatory and predictive power, as it explains 44.4 % of the variance in the input data, and the correlation between predicted and observed weighted percentage occurrence was 0.59 (Pearson s correlation) or 0.49 (Spearman s correlation). Page 23 of 43