Ecology of top predators in the North Sea – Baseline for and effects of offshore wind power developments

• Main Author: Peschko, Verena
• Other Authors: Garthe, Stefan, Wiltshire, Karen
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2019
• Subjects: thesis; ddc:500; ddc:570; ddc:590; offshore wind farms; ecological impacts; top predators; seabirds; grey seals; telemetry; distance sampling; behaviour; resource selection; distribution; abundance; rissa tridactyla; Uria aalge; uria
• Online Access: https://nbn-resolving.org/urn:nbn:de:gbv:8-mods-2020-00168-5; https://macau.uni-kiel.de/receive/macau_mods_00000528; https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/macau_derivate_00001536/202007_Dissertation_VPeschko.pdf

The North Sea is amongst the most intensively utilised sea areas worldwide and the marine habitat occupied by human uses substantially increased during the past years as numerous offshore wind farms (OWFs) were built. The construction of already approved OWFs and the consenting of additional areas for OWFs is still in progress. Due to the importance of apex predators for a healthy marine environment and their role as indicators for the state of the ecosystems it is of utmost importance to increase our knowledge on their habitat use and behaviour and to understand if and how they are affected by anthropogenic activities. In this thesis, fundamental knowledge on the ecology of several important top predator species is provided and applied as baseline information to investigate their reactions towards OWFs constructed in the southern North Sea. To provide a comprehensive view on the different aspects two methods were applied: Visual and digital surveys offer the opportunity to study the species abundance and distribution as well as changes of these on a large spatial and temporal scale. Telemetry of individual animals provides detailed information on their movements and behaviour during specific periods of their annual life cycle and enables to directly observe their reaction to changes in their environment. Five top predator species (including one species group) which differ substantially in their ecological requirements and constraints, e.g. due to their foraging behaviour, were chosen: black-legged kittiwakes (Rissa tridactyla), common guillemots (Uria aalge), the species group of loons (Gavia spp.), northern gannets (Morus bassanus), and grey seals (Halichoerus grypus). As wide ranging and abundant species they are prone to experience interference with OWFs at various locations. However, the reaction of seabirds towards large scale OWFs in the southern North Sea and towards OWFs located close to their breeding colonies, as well as their individual behaviour in response to OWFs were poorly studied so far. ...