Control of elmleaf blackberry invasion in a natural reserve in Argentina

The invasion of exotic plants is a serious problem for natural communities. The efficacy of the combination of physical and chemical methods to control blackberry invasion and their impact on native plant communities were evaluated. The experiment was conducted at Laguna de los Padres Reserve, located in the southeast of Buenos Aires Province, Argentina. In winter 2006, two areas were bulldozed. In one of them, blackberry plants were cut and left on the ground. In the other, plants were cut and the upper part of the soil was removed, digging out the crowns and roots. After regrowth, two chemical treatments were applied: glyphosate 2% and 4%, leaving plots without herbicide. The percentages of cover of blackberry and each one of the species growing were recorded. Measurements started in October 2006 and were made twice a month during spring–autumn 2006–2007 and 2007–2008. The methods evaluated in this study controlled blackberry and allowed the growth of other species. Glyphosate was more efficient if applied in late summer–early autumn. No differences between herbicide doses were found. The most intense physical treatment was more effective, leading to a higher cover of other species and proportion of natives. Here, the herbicide was not essential in the recovery of vegetation, although it was an important factor controlling blackberry. In places with less intense physical treatment, the herbicide application became important for the community recover. Control actions to recover the ecosystem should be constant in time using methods that take into account weed and native species features.