Environmental conditions and plant biomass in a field experiment : biomanipulation of macroarthropods

Changes of environmental conditions in mesocosms differentiated in the accessibility for epigean arthropods (closed and open for animals) were compared on a meadow of the Arrhenatheretalia order. In general, moisture of the exposed litter and of the underlying substrate did not differ between the open and closed treatments. Plant biomass, considered as an index of the environmental conditions, did not differentiate the two mesocosm types, either aboveground (total and subdivided into dead and living) or belowground. The open mesocosms were characterised by higher weight of fragmented plant material and of invertebrate faeces than the closed treatment.