Maintenance of the favourable conservation status in two Special Protection Areas in co-habitation with development of the Antwerp harbour

The growing Antwerp harbour on the left bank of the River Schelde has a considerable overlap with designated Birds and Habitats Directive areas (SPA and SAC). Harbour development projects threaten the favourable conservation status of the protected habitats and species. On the other hand the international conservation commitment hampers the harbour development. ‘Co-habitation’, the aim of the Flemish Government to maintain a balance between industrial and ecological needs is a key word in the present-day management of the region. The Deurganckdock case exemplifies possible problems and solutions for Natura 2000 in harbour development areas. Compliance with article 6 of the Habitats directive is the most complex issue. In this case it failed with respect to the assessment of adverse effects and several aspects of the compensation policy. Well defined conservation objectives and performance criteria are essential to the process and should be defined as soon as possible for any Natura 2000 site. Habitat creation/development as compensatory measure should start prior to and not simultaneously or after habitat destruction. Temporary compensations are no sustainable solutions and are only acceptable when an existing habitat is involved; temporary habitat creation is both an economic and ecological loss. Monitoring Natura 2000 sites is essential to successful adaptive management and the maintenance of a favourable conservation status, especially in highly dynamic areas such as harbour development areas

High levels of effective long-distance dispersal may blur ecotypic divergence in a rare terrestrial orchid

Background: Gene flow and adaptive divergence are key aspects of metapopulation dynamics and ecological speciation. Long-distance dispersal is hard to detect and few studies estimate dispersal in combination with adaptive divergence. The aim of this study was to investigate effective long-distance dispersal and adaptive divergence in the fen orchid (Liparis loeselii (L.) Rich.). We used amplified fragment length polymorphism (AFLP)-based assignment tests to quantify effective long-distance dispersal at two different regions in Northwest Europe. In addition, genomic divergence between fen orchid populations occupying two distinguishable habitats, wet dune slacks and alkaline fens, was investigated by a genome scan approach at different spatial scales (continental, landscape and regional) and based on 451 AFLP loci. Results: We expected that different habitats would contribute to strong divergence and restricted gene flow resulting in isolation-by-adaptation. Instead, we found remarkably high levels of effective long-distance seed dispersal and low levels of adaptive divergence. At least 15% of the assigned individuals likely originated from among-population dispersal events with dispersal distances up to 220 km. Six (1.3%) ‘outlier’ loci, potentially reflecting local adaptation to habitat-type, were identified with high statistical support. Of these, only one (0.22%) was a replicated outlier in multiple independent dune-fen population comparisons and thus possibly reflecting truly parallel divergence. Signals of adaptation in response to habitat type were most evident at the scale of individual populations. Conclusions: The findings of this study suggest that the homogenizing effect of effective long-distance seed dispersal may overwhelm divergent selection associated to habitat type in fen orchids in Northwest Europe