Prevalence of Haemosporidian Parasites in an Arctic Breeding Seabird Species-The Red-Throated Diver (Gavia stellata).

Haemosporida, vector-transmitted blood parasites, can have various effects and may also exert selection pressures on their hosts. In this study we analyse the presence of Haemosporida in a previously unstudied migratory seabird species, the red-throated diver Gavia stellata. Red-throated divers were sampled during winter and spring in the eastern German Bight (North Sea). We used molecular methods and data from a related tracking study to reveal (i) if red-throated divers are infected with Haemosporida of the genera Leucocytozoon, Plasmodium and Haemoproteus, and (ii) how infection and prevalence are linked with the breeding regions of infected individuals. Divers in this study were assigned to western Palearctic breeding grounds, namely Greenland, Svalbard, Norway and Arctic Russia. We found a prevalence of Leucocytozoon of 11.0% in all birds sampled (n = 45), of 33.0% in birds breeding in Norway (n = 3) and of 8.3% in birds breeding in Arctic Russia (n = 25). For two birds that were infected no breeding regions could be assigned. We identified two previously unknown lineages, one each of Plasmodium and Leucocytozoon. Haemosporida have not been detected in birds from Greenland (n = 2) and Svalbard (n = 2). In summary, this study presents the first record of Haemosporida in red-throated divers and reports a new lineage of each, Plasmodium and Leucocytozoon GAVSTE01 and GAVSTE02, respectively.

Satellite telemetry and digital aerial surveys show strong displacement of red-throated divers (Gavia stellata) from offshore wind farms.

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 German Bight (North Sea). We modelled the distribution of divers based on two independent data sets, digital aerial surveys and satellite telemetry, in relation to the dynamic offshore environment and anthropogenic pressures. Both data types found that divers were strongly displaced from wind farms in suitable habitat. The displacement effect gradually decreased with distance from the wind farms (being very strong up to 5 km away), but a significant effect could be detected up to 10-15 km away. The telemetry data further indicated that the displacement distance decreased with decreasing visibility. The displacement distance was also shorter during the day than during the night, potentially as a response to aviation and navigation lights of the wind farms. These findings should be taken into consideration in marine spatial planning to avoid cumulative impacts on red-throated diver populations.

A novel approach for assessing effects of ship traffic on distributions and movements of seabirds.

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 in the German Bight (North Sea) using satellite telemetry and digital aerial surveys with the aim of assessing effects of ship traffic on the distribution and movements of this species during the non-breeding season. Data from the automatic identification system of ships (AIS) were intersected with bird data and allowed detailed spatial and temporal analyses. During the study period, ship traffic was present throughout the main distribution area of divers. Depending on impact radius, only small areas existed in which ship traffic was present on less than 20% of the days. Ship traffic was dominated by fishing vessels and cargo ships, but also wind farm-related ships were frequently recorded. Red-throated divers were more abundant in areas with no or little concurrent ship traffic. Analysis of aerial survey data revealed strong effects of ship speed on divers: in areas with vessels sailing at high speed only a slow resettlement of the area was observed after the disturbance, while in areas with vessels sailing at medium speed the resettlement was more rapid during the observed time period of 7 hours. Data from satellite-tracking of divers suggest that large relocation distances of individuals are related to disturbance by ships which often trigger birds to take flight. Effective measures to reduce disturbance could include channeled traffic in sensitive areas, as well as speed limits for ships traveling within the protected marine area.

Adopting Bacteria in Order to Adapt to Water-How Reed Beetles Colonized the Wetlands (Coleoptera, Chrysomelidae, Donaciinae).

The present paper reviews the biology of reed beetles (Donaciinae), presents experimental data on the role of specific symbiotic bacteria, and describes a molecular method for the detection of those bacteria. Reed beetles are herbivores living on wetland plants, each species being mono- or oligo-phagous. They lay their eggs on the host plant and the larvae live underwater in the sediment attached to its roots. The larvae pupate there in a water-tight cocoon, which they build using a secretion that is produced by symbiotic bacteria. The bacteria are located in four blind sacs at the foregut of the larvae; in (female) adults they colonize two out of the six Malpighian tubules. Tetracycline treatment of larvae reduced their pupation rate, although the bacteria could not be fully eliminated. When the small amount of bacterial mass attached to eggs was experimentally removed before hatching, symbiont free larvae resulted, showing the external transmission of the bacteria to the offspring. Specific primers were designed to detect the bacteria, and to confirm their absence in manipulated larvae. The pupation underwater enabled the reed beetles to permanently colonize the wetlands and to diversify in this habitat underexploited by herbivorous insects (adaptive radiation).