Is ant fauna a good bio-indicator of coastal dune ecosystems in North-East of Algeria?

Abstract

Summary Ants are good bioindicators of habitats and of their quality in many ecosystems. However, their interest in the case of coastal dunes remains to be determined because the environments are instable or subject to strong constraints. The degree of preservation of the Jijel coastal dune system is variable and presents an environmental gradient (sea-land) of five habitats defined by vegetation: upper beach, embryonic, mobile, steady and wooded dune. The aim of the study is to determine if (i) these five habitats have characteristic ant assemblages; (ii) if the variation in ant richness along the gradient shows a continuous increase reflecting very strong disturbances or shows a peak reached before the most stable habitat, therefore at the level of a medium disturbance; and (iii) how environmental factors play on the different ant species. Seventeen stations spread over four sites were selected for the study of myrmecofauna by barber trap, bait, and manual collection, and of vegetation by the quadrats method. Overall, the ant richness profile along the gradient is consistent with an increase towards the most stable environments. The composition of ant communities varies according to habitats and is correlated with the composition of plant communities. The effects on ants of environmental factors deduced from the structure of the vegetation are analysed at the community and species levels. Along the habitat gradient, there is a quadratic relationship between the barycentre and the range of habitat of the species. Despite the small number of species, this group of insects gives interesting results in terms of sensitivity to disturbances.