|Studie naar de ecologie van de vrijlevende Plathelminthes (Turbellaria) van de zandstranden van de Belgische kust|
Jouk, P. (1992). Studie naar de ecologie van de vrijlevende Plathelminthes (Turbellaria) van de zandstranden van de Belgische kust. PhD Thesis. Limburgs Universitair Centrum: Diepenbeek. 2 volumes pp.
This dissertation contains the ecologic study of the sheath Plathelminthes ("Turbellaria ") of the Belgian coastal sandy beaches. In a first phase of the research 10 localities were sampled , spread along the entire coast, immediately processing the abiotic (mainly the sediment) and the non-fixed samples for the qualitative determination of the turbullarian fauna. The second phase of the research consisted of a quantitative analysis of the total meiofauna in six chosen localities, based on fixed samples, with, obviously, special attention for the Turbellaria. These were determined up to species level, while Nematoda, harpacticoida, gastrotricha and “other” meiofauna-organisms were only counted on the general taxon-level. On the one hand these data can be used to check the share and the importance of turbellaria in the entire meiofauna, both density and biomass. Also the samples contain an entire year cycle, through which the temporal evolution of the meiofauna can be traced. For most abundant turbellaria the life-cycli are being researched. On the other hand the data can be used to trace if there are several fauna compositions of the turbellaria fauna in different biotopes, and to see if and to what extend the abiotic factors (mainly the sediment) are determining for the composition of the turbellaria fauna. General conclusions. From this research we can generally conclude that for sandy localities both diversity and density and biomass of the turbellaria is higher in dynamic habitats than in localities with low “stress”. (if the stress factor(s) are too high, however, diversity, density and biomass can diminish again.) The total density of the meiofauna decreases with an increasing dynamic in the biotope, where the turbellaria in dynamic habitats are a (much) more important part of the meiofauna, than in localities with little “stress”. In terms of biomasses, the share of the turbellaria in the total meiofauna is even bigger than in terms of density, caused by the high individual biomasses of turbellaria compared to other meiofauna-organisms. For each type of biotope a clear difference between turbellariafauna can be reckognised. Finally one can state generally that fore sandy biotopes in temperate regions the life cyclus of most turbellaria species is univoltian.
- Vertical distribution of the free-living Plathelminthes (Turbellaria) from the sandy beaches of the Belgian coast in 1985 and 1986