Potential threats. Potential threats are those for which there is no clear evidence of direct links between the threat and Long-tailed Duck population impacts, but for which there is reason to believe that there may be an impact, either currently or one is anticipated during the lifetime of this plan. Pollution from hazardous substances in the Baltic Sea (Importance: Unknown, potentially low) Bioaccumulation of toxins, through consumption of bivalves that filter large volumes of water, is considered a potentially significant threat to Long-tailed Ducks in the non-breeding areas. Such pollutants may cause indirect mortality, reduced fitness, disturbed reproduction and pathological disorders in individuals, and thus have knock-on impacts on the population. In the Baltic Sea, many of the most harmful substances such as Polychlorinated biphenyls (PCBs), Dichlorodiphenyltrichloroethane (DDT/DDE) and Tributyltin (TBT) – which were primarily input decades ago – are still present in undesirable concentrations (Xxxx et al. 2011). Other substances have seen increasing trends, for example, levels of Hexabromocyclododecane (HBCDD) and Perfluorooctane sulphonate (PFOS) recorded in Guillemot Uria aalge eggs have shown increasing trends since the 1960s, which may be of high concern to other predatory bird species. Pharmaceuticals are also increasingly being recognized as environmental contaminants in the Baltic Sea, with potential adverse effects on Blue Mussels reported for some substances (HELCOM 2010). Toxin release from oil spills, both deliberate and accidental, is expected to rise given the rapid increase in oil extraction and transportation from the Arctic (see above). The main routes by which hazardous substances enter the Baltic ecosystem are i) point source pollution along the coast or inland catchments, ii) land-based diffuse sources such as agricultural runoff, iii) at sea activities such as shipping, iv) dredging, and v) atmospheric deposition of contaminants from various sources. Exposure concentrations to toxins in the Baltic Sea are relatively high compared with other sea areas, due to the enclosed brackish waters of the Baltic in which pollutants are not diluted to the same extent as in more open seas. Open-sea waters in the main basin of the Baltic Sea – the Northern Baltic Proper, and the Western and Eastern Gotland Basins – together with some areas of the Kiel and Mecklenburg Bights have been identified as the most contaminated areas (HELCOM 2010). Eutrophication and nu...
Potential threats. 3.4.1 Lead poisoning Lead shot is the preferred ammunition for many hunters. It is highly toxic and causes high mortality in many wildfowl, including non target species, which accidentally ingest spent shot pellets along with grit, used to aid digestion. The banning of lead shot over wetlands is widely recommended, and appropriate legislation is being introduced in many European countries. The use of lead shot is, however, legal in all of the major range states for Red-breasted Geese, and only in Bulgaria is a ban currently being considered. (Many hunters in countries where lead is banned continue to use lead shot in wetland areas contrary to the legislation.) Another potential source of poisoning is lead used as fishing weights, though the extent of use is probably far less in range states. It is currently unknown if lead poisoning is an issue in Red-breasted Geese, what the potential sources of lead are for this species, or whether lead poses a greater risk in particular parts of the flyway. Lead poisoning is not cited as a threat for Lesser White-fronted Geese. Importance: Unknown, potentially medium
Potential threats. Potential threats to the pink-foot population have been categorised according to sources and perceived root causes (Table 1). Potential consequences have also been listed. However, since the Svalbard population of pinkfeet continues to grow, the overall assessment is that none of these threats are significantly impacting the population level at the moment, although they may become important in the longer-term future. This section is not intended as a full risk assessment but merely outlines the anticipated actual / potential threats that the management framework may need to cope with. These threats may also vary between range states. Since the status of the population is dynamic the management framework will need to incorporate various forms of risk assessment at the flyway and regional levels. A key part of the risk assessment will require stakeholder input (there are always differing perceptions of risk) as well as monitoring to enable management plans to adapt to these changing threats. In addition some threats may be seen as opportunities in certain circumstances and time scales e.g. climate change could also increase the breeding habitat available due to a decrease of snow and ice cover, whilst increasing red fox numbers may naturally regulate the population.
