Guyonne F. E. Janss

Avian mortality from power lines: a morphologic approach of a species-specific mortality

Abstract Avian mortality from power lines is a species-specific mortality which affects several vulnerable and endangered species. Identifying the characteristics of species at risk of power line mortality can help solve this conservation problem. The relative abundance of bird species near power lines was compared with records of electrocution and collision casualties from these power lines to identify species-specific death risk as determined by wing morphology. Generally, collision victims were “poor” fliers, while electrocution victims were birds of prey, ravens and thermal soarers. Bird species were categorised by wing morphology and risk of either collision or electrocution. Three categories were identified: species with a high risk of collision, species with a high risk of electrocution and a third mixed group, susceptible to both these causes of death. The variables, weight, wing length, total length and tail length classified 88.6% of the species correctly in these three categories when used in a discriminant analysis. The classification can be used in a predictive model to identify species susceptible to power line mortality. The third mixed group warrants special attention from a conservation point of view because risk is not easily identified and depends on specific behaviour and local circumstances.

The effects of a wind farm on birds in a migration point: the Strait of Gibraltar

The interaction between birds and wind turbines is an important factor to consider when a wind farm is constructed. A wind farm and two control areas were studied in Tarifa (Andalusia Province, southern Spain, 30STF590000–30STE610950). Variables were studied along linear transects in each area and observations of flight were also recorded from fixed points in the wind farm. The main purpose of our research was to determine the impact and the degree of flight behavioural change in birds flights resulting from a wind farm. Soaring birds can detect the presence of the turbines because they change their flight direction when they fly near the turbines and their abundance did not seem to be affected. This is also supported by the low amount of dead birds we found in the whole study period in the wind farm area. More studies will be necessary after and before the construction of wind farms to assess changes in passerine populations. Windfarms do not appear to be more detrimental to birds than other man-made structures.

Avian electrocution mortality in relation to pole design and adjacent habitat in Spain

Quantitative differences were assessed in avian mortality by electrocution between the most frequent pole designs and habitat types in south-west Spain. Pin-type insulators in natural habitats accounted for 36.9% of total avian mortality. Including all species, we estimated a mean annual death rate of 4.5 birds per 100 poles (95% confidence interval: 3.0–6.03), of which 53.8% were diurnal birds of prey. We identified all power poles in the distribution area of the Spanish Imperial Eagle Aquila adalberti population of the Donana area. The estimated total mortality for adults was 0.38 birds per year and for immature eagles 3.38, which was 1.3% of the adult population and 30.0% of the mean annual number of fledged young. Adequate modification of 18.6% of power poles in the distribution area of the eagle population could reduce the total estimated mortality by 51.6%.

Using Wind Tunnels to Predict Bird Mortality in Wind Farms: The Case of Griffon Vultures

Background Wind farms have shown a spectacular growth during the last 15 years. Avian mortality through collision with moving rotor blades is well-known as one of the main adverse impacts of wind farms. In Spain, the griffon vulture incurs the highest mortality rates in wind farms. Methodology/Principal Findings As far as we know, this study is the first attempt to predict flight trajectories of birds in order to foresee potentially dangerous areas for wind farm development. We analyse topography and wind flows in relation to flight paths of griffon vultures, using a scaled model of the wind farm area in an aerodynamic wind tunnel, and test the difference between the observed flight paths of griffon vultures and the predominant wind flows. Different wind currents for each wind direction in the aerodynamic model were observed. Simulations of wind flows in a wind tunnel were compared with observed flight paths of griffon vultures. No statistical differences were detected between the observed flight trajectories of griffon vultures and the wind passages observed in our wind tunnel model. A significant correlation was found between dead vultures predicted proportion of vultures crossing those cells according to the aerodynamic model. Conclusions Griffon vulture flight routes matched the predominant wind flows in the area (i.e. they followed the routes where less flight effort was needed). We suggest using these kinds of simulations to predict flight paths over complex terrains can inform the location of wind turbines and thereby reduce soaring bird mortality.

Ecosystem services in European protected areas: Ambiguity in the views of scientists and managers?

Protected Areas are a key component of nature conservation. They can play an important role in counterbalancing the impacts of ecosystem degradation. For an optimal protection of a Protected Area it is essential to account for the variables underlying the major Ecosystem Services an area delivers, and the threats upon them. Here we show that the perception of these important variables differs markedly between scientists and managers of Protected Areas in mountains and transitional waters. Scientists emphasise variables of abiotic and biotic nature, whereas managers highlight socio-economic, cultural and anthropogenic variables. This indicates fundamental differences in perception. To be able to better protect an area it would be advisable to bring the perception of scientists and managers closer together. Intensified and harmonised communication across disciplinary and professional boundaries will be needed to implement and improve Ecosystem Service oriented management strategies in current and future Protected Areas.

Developing methods for assessing abundance and distribution of European oysters (Ostrea edulis) using towed video

Due to large-scale habitat losses and increasing pressures, benthic habitats in general, and perhaps oyster beds in particular, are commonly in decline and severely threatened on regional and global scales. Appropriate and cost-efficient methods for mapping and monitoring of the distribution, abundance and quality of remaining oyster populations are fundamental for sustainable management and conservation of these habitats and their associated values. Towed video has emerged as a promising method for surveying benthic communities in a both non-destructive and cost-efficient way. Here we examine its use as a tool for quantification and monitoring of oyster populations by (i) analysing how well abundances can be estimated and how living Ostrea edulis individuals can be distinguished from dead ones, (ii) estimating the variability within and among observers as well as the spatial variability at a number of scales, and finally (iii) evaluating the precision of estimated abundances under different scenarios for monitoring. Overall, the results show that the can be used to quantify abundance and occurrence of Ostrea edulis in heterogeneous environments. There was a strong correlation between abundances determined in the field and abundances estimated by video-analyses (r2 = 0.93), even though video analyses underestimated the total abundance of living oysters by 20%. Additionally, the method was largely repeatable within and among observers and revealed no evident bias in identification of living and dead oysters. We also concluded that the spatial variability was an order of magnitude larger than that due to observer errors. Subsequent modelling of precision showed that the total area sampled was the main determinant of precision and provided general method for determining precision. This study provides a thorough validation of the application of towed video on quantitative estimations of live oysters. The results suggest that the method can indeed be very useful for this purpose and we therefor recommend it for future monitoring of oysters and other threatened habitats and species.