Individual study: mechanical and manual control of prickly pear Opuntia dillenii in lakeside dunes at Laguna del Portil, southern Spain.
Abstract
We present the results of an intervention to control prickly pear Opuntia dillenii in an area of coastal dunes with Juniperus spp. and Pinus pinea at the 'Laguna del Portil' Site of Community Importance, Huelva, southern Spain, in 2015-2017. In the first stage, a total of 2,266 m3 (approximately 460 MT) of the cactus was removed using heavy machinery, which was supplemented by the manual removal of 4 MT of fragments. Subsequently, as part of the periodic control and monitoring work, a total of 200 and 126 kg of shoots and saplings were removed manually after 15 and 25 months respectively. Twenty-six months after the mechanical removal, the composition of native plant species in treated and reference plots (uninvaded areas that represent well-preserved native vegetation) provided evidence of natural recovery. The economic efficiency of the different control stages was compared. The results suggest that combining mechanical and manual methods, adapted to the abundance, size and distribution of the invasive plant, was an effective approach. Additionally, subsequent annual rounds of control appear to be sufficient to provide effective ongoing control of the invasion of Opuntia dillenii.