Effectiveness of management strategies in Acacia dealbata Link invasion, native vegetation and soil microbial community responses

Acacia dealbata Link is an aggressive invasive tree currently widely distributed but little information concerning its management is available. To our knowledge, this paper presents the first approach to its control in Europe. Presented assay was carried out in an invaded area in the NW of Spain using direct herbicide (triclopyr) spraying and herbicide application after cutting of saplings and adult plants. Biometrical measurements were periodically carried out and soil microbial community activity, plant diversity and species composition were monitored. A. dealbata individuals were severely affected by treatments, causing all of the treated individuals to die. Enzymatic activities and soil respiration were significantly enhanced when cutting and herbicide were applied in combination but not after herbicide application on its own. Species richness, diversity, evenness and cover were significantly reduced in the sprayed herbicide treatment one year after the last herbicide application, but the differences disappeared in the following spring. Plant species and functional group distribution were conditioned due to the treatment. This study provides the first approach to A. dealbata management in Europe. Due to the effectiveness of treatments and the absence of long-term effects, further application of triclopyr would seem to be feasible to reduce A. dealbata spreading.