A large-scale study at the Vrije Universiteit Brussel researching various wetlands that are visited by migratory birds during their migration shows that the Portuguese wetland formed by Tejo Estuary is a critical stopover for millions of migratory birds. However, the Portuguese government has plans to help transform this protected wetland into a new airport near Lisbon. "Because this wetland is used by a significant fraction of the population of Western European migratory birds, its disappearance would affect not only nature in Portugal, but also typical birds in Belgium, such as the black-tailed godwit and the avocet, which pass through or stay there during winter every year," says Lisa Partoens, who is conducting this research together with Evelien Deboelpaep within their doctorates under the supervision of Prof. Nico Koedam and Prof. Bram Vanschoenwinkel.
The researchers ranked 700 European and African wetlands along the important East Atlantic migratory route according to various criteria. In order to determine the importance of individual wetlands for this migration route, models were applied to high-resolution satellite maps on which all wetlands between 42 and 10 degrees north latitude were delineated. The connectivity models determine how well areas are interconnected: in other words, how easy or difficult it is for birds to reach wetland A wetland B from the wetland. Taking into account the size of the wetland and its position in the network, it appears that this Portuguese wetland is one of the 15 most important wetlands. The Portuguese wetland is therefore a critical stopover point for the entire East Atlantic migratory route.
The Portuguese government has plans for a new airport near Lisbon. The nature reserve, which is formed by the Tejo Estuary, would also be used for this purpose. The wetland area is part of the Natura 2000 European protection network. This means that a change of use is only possible if the airport cannot be constructed at another location and the area can be fully compensated elsewhere.
"In principle, a link in Natura 2000 should not simply be transformed into an airport. The wetland is an important stopping place for millions of migratory birds to complete their migration. Given the great importance of the system, it seems unlikely that the loss of such an ecosystem can easily be compensated elsewhere. The government's announcement caused a great deal of protest, including from Birdlife International and various Portuguese conservation organizations," concludes Partoens.
The research is financed by the Research Foundation - Flanders (FWO - Fonds voor Wetenschappelijk Onderzoek)