artisanal and industrial salt works still persist in the wetlands of Aveiro, Mondego,
Tagus, and Sado estuaries, along the western coast of the country, as well as in
wetlands along the southern coast of Algarve. According to figures from the most
recent national census in 2015, there were only 73 saltpans in the whole country,
which produced a total of 117 tons of salt (INE 2016). Once a thriving industry in
the majority of the estuaries and coastal lagoons of the Portuguese coast, the marine
salt extraction declined with the onset of new food conservation technologies and
the reduction or abandonment of the once-prosperous long-range fishing fleet,
particularly since the early 1960s (Rodrigues et al. 2011; Vieira and Bio 2014).
In this chapter, we provide a case study developed in the coastal lagoon of
Aveiro (Ria de Aveiro), evaluating the response of shorebirds using saltpans to the
impacts associated with the construction and operation of a new railway, both
during the breeding and the wintering seasons. Under this scope, our specific
objectives were to evaluate whether the railway affected (a) the numbers of the main
breeding shorebirds (Black-winged Stilt, Kentish plover and Little tern); (b) the
phenology and breeding success of Black-winged Stilt; and (c) the numbers, distribution, and activity of wintering shorebirds.
Methodology
Study Area
The study was carried out in Ria de Aveiro (Fig. 12.1), which is a complex lagoon
system located in western Portugal at the mouth of the Vouga River that covers an
area of approximately 450 km
2 . For centuries, marine salt extraction occupied a large
part of this system (Bastos 2009; Rodrigues et al. 2011). By the early 1970s, there
were still some 270 saltpans (1160 ha), but in subsequent decades, most of these
saltpans were abandoned, flooded, and/or converted for other purposes (e.g., aquaculture production), with only nine saltpans (56 ha) persisting in 2007 (Bastos 2009;
Rodrigues et al. 2011). In contrast, a busy trading and fishing harbor has grown in the
last few decades, particularly since it was linked by a highway to the Spanish border.
To connect the harbor to the national rail network, a new railroad connection about
9 km long started to be built in 2007 (REFER 2009). The engineering and environmental problems faced by the project were challenging, because this was a
densely populated area, and Ria de Aveiro is a wetland included in the Natura 2000
network, established by the European Directive 92/43/EEC. Furthermore, the proposed rail path crossed important wetland areas, including eight of the last remaining
untransformed saltpans, and there were no technically viable alternatives. For this
reason, it was decided that the railway should cross the saltpans and adjoining areas
through a 5.5 km viaduct, to minimize the loss of important shorebird habitats.
Despite these efforts, three saltpans were directly affected by sustaining viaduct
pillars (Fig. 12.1), or the construction of a service road (REFER 2009).
12 Evaluating the Impacts of a New Railway on Shorebirds …
199
Tagus, and Sado estuaries, along the western coast of the country, as well as in
wetlands along the southern coast of Algarve. According to figures from the most
recent national census in 2015, there were only 73 saltpans in the whole country,
which produced a total of 117 tons of salt (INE 2016). Once a thriving industry in
the majority of the estuaries and coastal lagoons of the Portuguese coast, the marine
salt extraction declined with the onset of new food conservation technologies and
the reduction or abandonment of the once-prosperous long-range fishing fleet,
particularly since the early 1960s (Rodrigues et al. 2011; Vieira and Bio 2014).
In this chapter, we provide a case study developed in the coastal lagoon of
Aveiro (Ria de Aveiro), evaluating the response of shorebirds using saltpans to the
impacts associated with the construction and operation of a new railway, both
during the breeding and the wintering seasons. Under this scope, our specific
objectives were to evaluate whether the railway affected (a) the numbers of the main
breeding shorebirds (Black-winged Stilt, Kentish plover and Little tern); (b) the
phenology and breeding success of Black-winged Stilt; and (c) the numbers, distribution, and activity of wintering shorebirds.
Methodology
Study Area
The study was carried out in Ria de Aveiro (Fig. 12.1), which is a complex lagoon
system located in western Portugal at the mouth of the Vouga River that covers an
area of approximately 450 km
2 . For centuries, marine salt extraction occupied a large
part of this system (Bastos 2009; Rodrigues et al. 2011). By the early 1970s, there
were still some 270 saltpans (1160 ha), but in subsequent decades, most of these
saltpans were abandoned, flooded, and/or converted for other purposes (e.g., aquaculture production), with only nine saltpans (56 ha) persisting in 2007 (Bastos 2009;
Rodrigues et al. 2011). In contrast, a busy trading and fishing harbor has grown in the
last few decades, particularly since it was linked by a highway to the Spanish border.
To connect the harbor to the national rail network, a new railroad connection about
9 km long started to be built in 2007 (REFER 2009). The engineering and environmental problems faced by the project were challenging, because this was a
densely populated area, and Ria de Aveiro is a wetland included in the Natura 2000
network, established by the European Directive 92/43/EEC. Furthermore, the proposed rail path crossed important wetland areas, including eight of the last remaining
untransformed saltpans, and there were no technically viable alternatives. For this
reason, it was decided that the railway should cross the saltpans and adjoining areas
through a 5.5 km viaduct, to minimize the loss of important shorebird habitats.
Despite these efforts, three saltpans were directly affected by sustaining viaduct
pillars (Fig. 12.1), or the construction of a service road (REFER 2009).
12 Evaluating the Impacts of a New Railway on Shorebirds …
199