Competition between halophytes and invasive species: Dittrichia viscosa and Limbarda crithmoides: A study case from the Valencian salt marshes

Dittrichia viscosa is a Mediterranean native species, normally associated with degraded and anthropogenic influenced environments, which is expanding its distribution to habitats sheltering diverse and threatened species, as salt marshes. Although it is not an alien species, due to its ability to compete with other species, it may be considered as invasive. Its stress tolerance was compared to a taxonomically closely related species Limbarda crithmoides, formerly both ascribed in the genus Inula. A multidisciplinary approach based on field, germination, and physiological and biochemical studies revealed that D. viscosa represents a threat for halophyte flora only at lower salinities, as those registered at the borders of salt marshes, as it tolerates only a moderate level of salt stress. The results of this study intend to be of interest for salt marshes management as they offer information on the extent to which D. viscosa can act as invasive in these important habitats.