In the past, the dog whelk Nucella lapillus (Mollusca, Gastropoda, Muricidae) used to be a common species on jetties and groynes along the Belgian coast. During the seventies, the species became increasingly rare and the last Belgian specimen observed in situ was found in 1981. The extinction of the species is attributed to the use of paintings containing tributyltin (TBT) on the hulls of ships as antifouling protection. TBT dilutes in seawater and, even at extremely low concentration, sterilizes dog whelks. Since 1990, the use of Tributyltin (TBT) was restricted to ships smaller than 25 m; in 2003, it was totally forbidden and in 2008 old TBT paintings had to be removed from ship hulls. As a consequence the concentration in TBT of seawater presumably decreased in Belgian waters. On November 17th, 2012, several living adult dog whelks and 40 to 50 spawns ofthat species were observed on the concrete blocks of the western jetty of Zeebrugge harbour, indicating recolonization of the species in Belgium at least in one locality.
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RBINS Staff Publications
Urbanization is one of the major causes of the destruction of natural habitats in the world. Cities are urban heat islands and can thus significantly influence populations of plants and animals. The research project SPEEDY investigated the effects of urbanization in northern Belgium with a nested sampling design at local and landscape scales for a variety of organisms. Here, we tested the effects of urbanization on non-marine ostracod communities, sampling 81 small pools in three urbanization categories, as defined by percentage built up cover (low, intermediate, high). We identified 17 ostracod species, together occurring in 60 of the 81 sampled pools. We found that urbanization per se had no significant effect on ostracod communities. Of all the measured local factors, ammonium and total phosphorus concentrations had a significant effect on the community structure. In contrast, water temperature had no significant effect, most likely because the ostracod species found in northern Belgium in the present survey mostly have wide temperature tolerances.
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RBINS Staff Publications 2021
