Changes in Plants and Invertebrate Animals Communities along Gradients of Petroleum Products Pollution

Abstract

In this work, we investigated the effects of petroleum products contamination, caused by petrol stations rejects, on the vegetation and soil invertebrate animal communities. Three sites near two petrol stations were chosen, and the vegetation was inventoried during each season of the year. The invertebrates were sampled in the third site using Pitfall traps. Results indicated an influence of the petrol stations rejects on soil properties (TPH, N, C, pH and moisture). It was the same for plant species and invertebrate communities that were influenced through the abundance, species richness, biological diversity (H’) and species evenness (J), especially in the most contaminated zones. Some weed plant species showed a tolerance to the contamination, as Xanthium strumarium, Avena fatua, Conium maculatum and Oxalis pes-caprae, and their establishment may have been facilitated by the disturbances created by the petrol stations rejects. Also, some invertebrate orders, as Isopoda and Panpulmonata were mainly present in the contaminated zones. High levels of petroleum products contamination and the changes they can induce in soil properties, can affect the vegetation and soil invertebrates, by influencing the abundance and species richness and by facilitating the establishment of some species, like weed species in the vegetation case.