Invasive Asian oysters help threatened Dutch oysters


This 2011 video is about Patella sp. and Ostrea edulis oyster, along the coast of Brittany in France.

From Marine Biology Research, 25 June 2018:

Return of the native facilitated by the invasive? Population composition, substrate preferences and epibenthic species richness of a recently discovered shellfish reef with native European flat oysters (Ostrea edulis) in the North Sea

ABSTRACT

After being ecologically extinct for almost a century, the discovery of a shellfish reef with native European flat oysters (Ostrea edulis) in the Dutch coastal area of the North Sea by the authors of this study called for an extensive survey to better understand some of the key requirements for the return of the native oyster in coastal waters. We assessed habitat conditions, its potential for increasing biodiversity, and the role of substrate provision by other bivalves such as the invasive alien Pacific oyster (Crassostrea gigas). Using underwater visual census, O. edulis size-frequency distributions and attachment substrate was investigated, as well as the composition of the epibenthic community and substrata types inside quadrats that were distributed across the reef. This reef was found to be composed of native European flat oysters, invasive alien Pacific oysters and blue mussels (Mytilus edulis), alternated with sandy patches.

The O. edulis population (6.8 ± 0.6 oysters m−2) consisted of individuals of different size classes. In quadrats with native and non-native oysters the number of epibenthic species was 60% higher compared to adjacent sand patches within the reef.

Notably, our results showed that the native oyster predominantly used shell (fragments) of the invasive Pacific oyster as settlement substrate (81% of individuals). Our results optimistically show that conditions for native oyster restoration can be suitable at a local scale in the coastal North Sea area and suggest that the return of native oysters may be facilitated by novel substrate provided by invasive oysters at sites where their distribution overlap.

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Hornets at their nest, video


This 7 August 2018 video from Arnhem city in the Netherlands is about hornets at their nest.

Everdien van der Bijl made this video from a distance, with a 500mm telephoto lens. Hornets are not the most aggressive wasp species. But if you come too close to their nest, they will sting. Their stings are more painful than those of smaller wasp species.

Special beetle discovered on Texel island


This 2009 video from Slovakia is called Buprestis (Ancylocheira) novemmaculata novemmaculata, Linnaeus, 1767.

Warden Erik van der Spek on Texel island in the Netherlands reports today:

At the work shed of Staatsbosbeheer on Texel the jewel beetle Buprestis novemmaculata was found. Until now, this beetle was only known in the Netherlands from the Bergen and Schoorl dune forest, the first sighting there was in 1997. …

Presumably the closest natural population can be found in Alsace

in France.