Ecological characteristics of dayas and their impact on edaphic wildlife in Algeria

Abstract

The station selected for this study is characterized by specific ecological conditions. The plant transect conducted in this Daya has identified two plant species with a recovery rate of 18.7%. Ziziphus lotus species dominated and represent a recovery rate of 16.3%. Pistacia atlantica as second species has only 9.4% of recovery rate. A fauna inventory has identified 904 individuals representing 175 species which are divided into 18 orders and 3 classes with that of Gastropoda, Arachnida and those of insecta. The latter occupies the first place with 865 individuals and 153 species. Arachnida class occupies the second place with 20 species and the third place goes to that of Gastropoda with 2 species. In the insecta class, the Order of the Coleoptera is the high population with 75 species, followed by that of the Hymenoptera with 32 species. In the 3^rd place, we find the Diptera with 21 species. The orders of Actinedida, Solifugae, Neuroptera, Oribatida, Gamasida and Heteroptera are represented only by one or two individuals and one species for each. The richest family in terms of species is that of the Formicidae with 20 species followed by the Carabidae with 13 species. The collected population at the Daya of Bowden seen to be evolving with the increasing temperature, whereas the specific resources seen to act independently from the latter, but we note that number of the species is significant at the decrease of rainfall. The wind which has a constant speed during most of the year seems to have no direct effect on the soil fauna. The analysis of the acarofauna revealed the presence of only one species which is Oppia bicarinata. The Oribatida mites being as biological indicators in form us about the status of the soil at the Daya. In fact in spite of the favourable conditions for their development, the obtained results show that there are other factors which can influence their presence. Regarding the topography and the geomorphology characteristics, these Dayas constitute basins which are filled up with water in winter period. This state can significantly harm the evolution of the Oribatida mites. The second factor is that of the wind, the geographic situation of the Daya in desert region which constitutes large and open environment helps this factor to have a very important action especially in summer period. This action doesn’t have a direct effect on the acarofauna but more much on the litter which constitute a very important nutritive factor of the Oribatida mites.