Search publications of the members of the Royal Belgian institute of natural Sciences
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The effect of successional stage and salinity on the vertical distribution of seeds in salt marsh soils
- Seed bank density and similarity between above-ground vegetation and seed bank with depth were compared between two adjacent salt marshes that differ in age. In addition, the effect of salinity on the variation in seed bank density and similarity between above-ground vegetation and seed bank with depth was compared between euhaline against mesohaline conditions in three salt marshes. Ten plots of 2 m x 2 m were situated in a new salt marsh (existing since 2002) and 80 plots in three old salt marshes. Soil samples were collected at three different depths (0-5, 5-10, 10-15 cm) in spring 2006. Soil seed bank was investigated in germination experiments under greenhouse conditions. Germination experiments lasted 6 months and all seedlings were identified and removed after identification. Above-ground vegetation composition was determined during the growing season in all plots. Viable seed density was calculated for each plot and for the three different depths; the similarity between seed bank and floristic composition of the above-ground vegetation was calculated. A general linear model was used to investigate the effect of soil depth, salinity and age of the salt marsh on density and similarity between seed bank and above-ground vegetation. The results showed that seed density decreased with depth in all salt marshes, irrespective of their age and soil salinity. Seed density and similarity between seed bank and above-ground vegetation were higher in the new salt marsh than in the old one in the same study area. This is because in young as well as in old successional stages, the seed bank was mostly composed of new colonizers, while most perennial species were absent from the soil seed bank, although they were dominant in the standing vegetation of the old salt marsh. The characteristics of the seed bank of a mesohaline salt marsh were found not to be fundamentally different from that of both euhaline salt marshes. (C) 2010 Elsevier GmbH. All rights reserved.
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The effects of forest patch size and matrix type on changes in carabid beetle assemblages in an urbanized landscape
- In this study we compared ground beetles (Carabidae) from a range of different forest fragments along an urbanization gradient in Brussels, Belgium. We address the following questions: (i) How does the degree of urbanization in the surrounding habitat affect forest beetles, and does it interact with the effects of patch size and distance to forest edge? (ii) Do these factors have a different effect at the level of individual species, habitat affinity groups or total community? During 2002 we sampled 13 forest plots in 10 forest patches, ranging in size from 5.27 to 4383 ha. The beetles were captured using transects of pitfall traps from the edge to a distance of 100 m into each woodland and identified to species level. Effects of urbanization, forest size and forest edge were evaluated on total species number, abundance and habitat affinity groups and ten abundant, widespread model carabid species. Overall, the effects of urbanization, forest size and edge effects slightly influenced total species richness and abundance but appeared to have a major effect on ground beetle assemblages through species specific responses. More urbanized sites had significantly fewer forest specialists and more generalist species. Large forest fragments were favoured by forest specialist species while generalist species and species frequently associated with forest (forest generalists) dominated the smaller forests. Forest edges mainly harboured generalist species while forest specialist species were more frequent into the forests if the forest patches were large enough, otherwise they disappeared due to the destruction or impoverishment of their habitat. Our results show the importance of differentiating between habitat affinity, especially habitat generalists versus specialists, the latter having a higher value in nature conservation, and merely the quantity of species represented in human-dominated areas. (c) 2008 Elsevier Ltd. All rights reserved.
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The importance of biological factors affecting trace metal concentration as revealed from accumulation patterns in co-occurring terrestrial invertebrates
- As physicochemical properties of the soil highly influence the bioavailable fraction of a particular trace metal, measured metal body burdens in a particular species are often assumed to be more reliable estimators of the contamination of the biota. To test this we compared the Cd, Cu and Zn content of three spiders (generalist predators) and two amphipods (detritivores), co-occurring in seven tidal marshes along the river Schelde, between each other and with the total metal concentrations and the concentrations of four sequential extractions of the soils. Correlations were significant in only one case and significant site x species interactions for all metals demonstrate that factors affecting metal concentration were species and site specific and not solely determined by site specific characteristics. These results emphasize that site and species specific biological factors might be of the utmost importance in determining the contamination of the biota, at least for higher trophic levels. A hypothetical example clarifies these findings. (C) 2003 Elsevier Ltd. All rights reserved.
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The richness and paucity of the spider fauna of the Belgian coast.
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La Formation des schistes noires de Matagne et l'extinction du Dévonien Supérieur
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A single tooth replacement pattern generates diversity in the dentition in cichlids of the tribe Eretmodini, endemic to Lake Tanganyika.pdf
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Biology of the Soricidae
- Crocidura is the largest shrew genus, and occurs in most of the Old World. Its taxonomy is complex, and some species are morphologically so similar that they are allocated to “species groups”. Among the African Crocidura, several species are in need of taxonomic revision or are known by a few speci- mens only. Additional sampling is necessary to in- crease the number of specimens available in order to perform multivariate analyses of morphological characters. Meanwhile, molecular tools might help solve taxonomical difficulties and select specimens for further analyses. We used a combined morpho- logical and molecular approach to investigate spe- cies boundaries and phylogenetic relationships within African Crocidura species groups. We se- quenced part of the 16s rRNA mitochondrial gene of 131 specimens, representing a minimum of 30 morphologically defined species. Mitochondrial DNA sequences confirmed the distinctness of spe- cies in groups where cranio-dental characters allow reliable specific identification, but failed to confirm the differentiation of species within the most com- plex species groups. Within two of these groups, haplotypes tended to cluster by localities rather than by putative species, suggesting potential synonymy. We also detected three potentially new or unrecog- nized species. Our findings are encouraging, but will have to be further investigated using multivariate analyses of morphological characters and additional molecular analyses.
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Chapter 14 Genetic Traces Of Environmental Variations In Ancient Lakes
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De la phylogénie comparée à la biogéographie historique l'exemple des quelques mammifères forestiers d'Afrique Centrale
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Lake level fluctuations and speciation in rock-dwelling cichlid fish in lake Tanganyika, East Africa
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Mitochondrial Phylogeny of African woord mice, genus Hylomyscus (Rodentia, Muridae): Implications for their taxonomy and biogeography
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Mitochondrial phylogeny reveals differential modes of chromosomal evolution in ther genus tatera (Rodentia: Gerbillinae) in Africa
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Patterns of diversification in two African forest shrews: Sylvisorex johnstoni and Sylvisorex ollula (Soricidae, Insectiovora) in relation to paleo-environmental changes
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Respiration of Sepia officinalis during embryonic and early juvenile age
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Small mammals morphology and molecules - Tale bearing tenant of the Nigerian southwestern forest block
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The effect of complexation by organic ligands on the bioavailability of copper to the brine shrimp Artemia sp..pdf
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The Tanganyika problem comments on the taxonomy and distribution patterns of its cichlid fauna.pdf
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Acceptance of two native myrmecophilous species, Platyarthrus hoffmannseggii (Isopoda : Oniscidea) and Cyphoderus albinus (Collembola : Cyphoderidae) by the introduced invasive garden ant Lasius neglectus (Hymenoptera : Formicidae) in Belgium
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Ant biodiversity conservation in Belgian calcareous grasslands: active management is vital
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Centipede communities on the inland dunes of eastern Flanders (Belgium)
