Effects of metal contamination on the activity and diversity of carabid beetles in an ancient Pb-Zn mining area at Plombières (Belgium)

Carabid beetles were monthly sampled with pitfall traps in the ancient Pb-Zn mining area of Plombieres during one year. Based on the total soil concentrations of lead, zinc, cadmium and copper, it was expected that zinc would probably have the most adverse effects on the populations. Activity and species richness of carabid beetles were, however, not significantly correlated with total zinc concentration nor with the water soluble and the calciumchloride extractable concentration. In fact, despite the high soil concentrations, carabid beetles did not seem to be affected in the study area. The apparent lack of effects at the high observed zinc concentrations is probably caused by the low bioavailability of zinc to the beetles in the litter of the study sites which was also reflected in the low observed water soluble zinc concentrations

Inter- and intraspecific genetic and morphological variation in a sibling pair of carabid species

BACKGROUND: Pogonus littoralis and Pogonus chalceus are very close related species with quite different ecological preferences within salt marshes. We study the evolutionary processes in and between these presumably young species. Therefore, we compare the variation in ecologically relevant characters and the genetic variation within one of the species (intraspecific differentiation) with the variation of the two types of characters between the two species (interspecific variation). Data are compared between two independent sets of populations, one set at a small geographical scale (the ecologically diverse Guérande area in France) and the other set at a Atlantic-Mediterranean scale. RESULTS: Body and relative wing size and IDH1 allozyme data show that the intraspecific variation in P. chalceus is high and in the same range as the interspecific variation (P. chalceus versus P. littoralis). Based on neutral markers (other allozymes and mitochondrial DNA) on the other hand, the intraspecific variation in P. chalceus is much lower in comparison to the interspecific variation. CONCLUSION: The different ecotypes in the highly polytypic species P. chalceus are as highly differentiated in ecological characters as true species, but are not recognised as such by screening neutral DNA polymorphisms. This can be interpreted as a case of ongoing speciation driven by natural selection adapting each ecotype to its respective ecological niche. The same ecological process can be recognised in the differentiation between the two sister species, where en plus reproductive isolation between the two gene pools occurred, allowing independent drift and mutation accumulation in neutral genetic characters

Loss of genetic diversity and increased genetic structuring in response to forest area reduction in a ground dwelling insect: a case study of the flightless carabid beetle Carabus problematicus (Coleoptera, Carabidae)

1.Old growth temperate broadleaved forests are characterised by a large proportion of forest specialists with low dispersal capability. Hence, species bound to this habitat are expected to be highly susceptible to the effects of decreasing patch size and increasing isolation. 2. Here, we investigate the relative effect of both factors by genotyping individuals of a flightless and forest specialist beetle Carabus problematicus from 29 populations, sampled in 21 different forest fragments in Belgium, at eight microsatellite loci. 3. A high degree of genetic differentiation among fragments was observed, with populations from smaller forests being considerably more differentiated and characterised by a lower genetic diversity compared to those of larger forests. 4. A more detailed study on forest remnants of a former historic continuous woodland area revealed that population differentiation was high among, but not within remnants, irrespective of geographical distance. This suggests that patch fragmentation rather than geographical distance is the ultimate factor that hampers gene flow in this species. 5. he results indicate that gene flow among suitable habitat patches is primarily reduced by the inability of this specialised species to traverse the landscape matrix. This lack of dispersal may pose a serious threat for the persistence of C. problematicus and ecologically similar species, and suggests that present populations can best be protected by securing or increasing the size of existing habitat patches

Een Karolingische vlechtwerkwaterput uit Zerkegem (gem. Jabbeke, prov. West-Vlaanderen): culturele en ecologische archaeologica

Midden 1991 werd door het Gemeentebestuur van Jabbeke besloten een sociale verkaveling te realiseren in het woonuitbreidingsgebied van de deelgemente Zerkegem. Deze nieuwe verkaveling zou ingeplant worden ten zuiden van de dorpskom, tussen de Mosselstraat en de Paradijsweg. Over de archeologische potentie van het terrein zelf waren op dat ogenblik geen gegevens voorhanden. Een vluchtig onderzoek van de schaarse historische studies bracht geen soelaas en ook de oude kartografische bronnen leverden niets op. Enkel de recente topografische kaarten maakten gewag van een loods op de oostelijke helft van het terrein tot in het begin van de jaren \u2780