and waterfowl (Lourenço et al. 2009; Alves et al. 2011). Also, the temporal patterns
of species’ composition were similar to those of other wetlands, with diversity and
abundance of most species peaking during the autumn and, to a lesser extent, spring
migration periods, and in winter. There was no evidence that the spatial patterns of
bird assemblages were affected by proximity to the railway, with species richness
and abundances not showing significant differences in areas close to and far from the
railway. Although higher densities of some species were recorded far from the
railway on some occasions, there was no consistent pattern due to strong variation
across species and seasons, and through the tidal cycle. Overall, we could find no
noticeable exclusion effects of this railway line on wetland birds, which is in line
Fig. 11.2 Variation in mean densities (birds/ha) of the most abundant wetland birds counted in
sectors close to (<500 m) and far from (>500 m) the railway line, in relation to season and level of
the tidal cycle
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