Wind farms in proximity to marine protected areas put conservation targets at risk

ABSTRACT

Special Protection Areas (SPAs) are an important EU legislative tool to protect species biodiversity. Red-throated loons Gavia stellata and black-throated loons G. arctica are the key species in the designation of the SPA ’Eastern German Bight’, located in the German Exclusive Economic Zone of the North Sea; however, one offshore windfarm (OWF) has been constructed within and four OWFs just outside this SPA within the last few years. The current study integrated previous findings on the strong avoidance of OWFs by loons to assess the effects of these developments on the SPA. OWFs affected on average half of the SPA. We observed a major change in the overall distribution of loons in the study area; the area with the highest densities had shifted southwest and the spatial extent of the high-density area had decreased. The northern third of the SPA, which previously often included the highest concentrations, had been almost abandoned by loons. Variability in loon distribution was significantly restricted after the OWFs became operational. These findings have important implications for the functioning of this Marine Protected Area. The construction of OWFs within the loons’ foraging habitats has increasingly restricted their spatial flexibility and thus their foraging behaviour. We conclude that the establishment of OWFs inside and even adjacent to a protected area counteracts its conservation targets. Ignoring such effects may lead to a loss of such retreats for threatened species and habitats.

RESULTS

Disturbance effects by OWFs on loons were shown to affect huge proportions of the SPA Eastern German Bight, ranging from more than a third to around two thirds of the SPA, depending on which disturbance distance was used (Table 1, Fig. 2). On average, half of the SPA was affected, with approximately half of this affected area impacted by the four wind farms located entirely outside the SPA (Table 1, Fig. 2). We observed a major change in the overall distribution of loons in the study area (Fig. 3). The core distribution shifted to some degree in the five 2-year periods before the establishment of the OWFs, and remained almost identical in the three 2-year periods after OWF operations commenced. Furthermore, the area with the highest densities shifted southwest and the spatial extent of the high-density area decreased. The northern third of the SPA, which had often exhibited the highest concentrations, has been almost completely abandoned by loons (Fig. 3). The spatial variability between subsequent 2-year periods varied over time (Fig. 4). The two lowest values coincided with the operational stage of the OWFs, while spatial variability was higher in all five periods before establishment of the OWFs, and much higher in four cases (Fig. 4).