It was noted that Acacia decurrens Willd. invaded the park and threatened the cork oak ecosystem (Beddiar et al., 2012). Results showed the negative effect of acacia on cork oak growth, its mycorrhizal status as well as on the morphotypic diversity of its ectomycorrhizae. The plant and fungal biodiversity decreased significantly in the sites invaded by this acacia species. A. decurrens homogenized invaded areas and was found to have the ability to inhibit and compete with native species (Afrianto et al., 2010).