Fig. 1From: Radical changes in the Wadden Sea fauna and flora over the last 2,000 yearsPopulation trends of harbour seals (solid line) and grey seals (dotted line) in the Wadden Sea since 1960 as estimated from aerial counts (data adapted from Reijnders 1992; de Jong et al. 1999; Reineking 2002; TSEG 2002). The gray bar on the left indicates the potential abundance estimate for harbour seals in 1900 (after Reijnders 1992)Back to article page