Zandhagedissen in de Amsterdamse Waterleidingduinen: 30 jaar monitoring

Net als in veel delen van Nederland nam de zandhagedis in de Amsterdamse Waterleidingduinen aan het begin van de tellingen toe, maar rond 2010 beginnen de aantallen te dalen. Dit artikel gaat in op de ontwikkelingen in het gebied en beschrijft de mogelijke oorzaken van achteruitgang. Monitoring Sand lizards at Amsterdamse Waterleidingduinen Long-term standardized monitoring shows that sand lizards (Lacerta agilis) increased during the 1990s and the first decade of the twentyfirst century at Amsterdamse Waterleidingduinen, a 3.400 ha. lime-rich Dutch coastal dune system. Since then, the numbers of sand lizards have declined, locally and nationwide. The declines have more widespread causes, but they started earlier and were steeper at Amsterdamse Waterleidingduinen, also compared to nearby similar dune systems. Therefore local causes also seem to play a part. A series of publications about the Amsterdamse Waterleidingduinen shows that a steep increase of the feral fallow deer (Dama dama) population led to a high grazing pressure that a(ected dune habitats. As a result, many plant and animal species have steeply declined. This article advocates that locally sand lizards have probably su(ered from decreased vegetation structure due to overgrazing. Furthermore, European rabbits (Oryctolagus cuniculus) have a very positive effect on dune landscapes by creating small scale, varied mosaic vegetation structures, favoured habitats by sand lizards. Rabbit numbers have however dwindled over the past decade due to (new variants of) diseases. Since 2016 deer numbers have been reduced by culling, and currently there are experiments to re-introduce rabbits. Hopefully these measures will lead to a more varied vegetation structure in the future, improving sand lizard habitat.