A heavy toll
Human pressure is often intense on migratory animals and on the habitats they need to survive. Unsustainable hunting and fishing practices and incidental capture in fisheries take a heavy toll on thousands of species. Destruction of wetlands, forests and grasslands removes food and shelter vital to life. Barriers to migration such as roads, fences, dams, power lines and wind farms can disrupt migratory patterns and result in a significant number of deaths. Birds face the danger of electrocution, injuries or death caused by power transmission lines or towers. Armed conflicts pose a threat to humans and animals alike.
The introduction of alien species and the harmful effects of industrial and agricultural pollutants are further risks. The potentially huge impact of climate change is just beginning to be understood, but it is predicted that migration patterns and reproduction will be disrupted. As a result, many migratory animals are becoming increasingly rare. A great many are threatened with extinction.
A need for international action
While migrating, many species cross national borders, artificial constructs which are, of course, not recognised by animals. Borders not only divide countries, they also separate national legislation, interests and political priorities. Migratory animals are particularly vulnerable in international waters. There, the lack of national jurisdiction makes it even morenecessary for countries to assume their shared responsibility to conserve this common natural heritage.
Some of these threats are listed below.
Habitat loss and degradation - Example: Barriers to migration in Central Asia
Unsustainable fishing - Example: Bycatch