Abstract:
This study represents a continuation of research carried out in Danube Delta Biosphere Reserve, within the Core
Program, financed by the Romanian Ministry of Research and Innovation. Communities of edaphic microarthropods in
halophilic ecosystems of D.D.B.R. have been investigated to assess their vulnerability. The analysis was performed
qualitatively and quantitatively, on systematic and trophic groups, in a space-time dynamic. The obtained results have
shown that the structural features of edaphic mesofauna depend both on the vegetation and the biopedoclimatic
conditions, in general the halophilic habitats being restrictive for most edaphic microarthropods. The highest density is
observed in a salinized wet meadow, characterized by a great floral diversity. The lowest population abundance was
recorded in the grassland with the poorest vegetation, where Salicornia europaea is the only dominant species. The
analysis of the relationships between the trophic groups highlights the dominance of the detritomicrophytophages
versus zoophages, a situation that is usually found in meadow ecosystems. The analysis of the seasonal dynamics of the
mesofauna as a whole revealed that in most of the studied ecosystems, under summer drought conditions there was a
decrease in the total number of edaphic mesofauna (1.6-4.3 times), the most significant decrease (2 -20 times) being the
number of springtails that are known to be susceptible to edaphic dryness. The numerical ratio between oribatid mites
and springtails (the main groups of detritomicrophytophages) is in most cases supraunitary, indicating that in the
nutrient cycling the humification processes are predominant.
