Definição de método de controle para vimeiros invasores (Salix x rubens)

Abstract

Invasive alien species are one of the biggest threats to biodiversity in protected areas. Experiments to define effective control methods for these species are essential if management projects and programs are to be implemented in protected areas. The invasive hybrid Salix x rubens, popularly known as willows, is an example of an invasive tree in riparian areas in the highlands of southern Brazil, as well as in other regions of the world. Willows cause significant physical and biological impacts in riparian areas, such as increased erosion and flooding; reduced water quality, availability and flow; and altered habitat for various species of plants and animals. The general aim of this study was to experimentally define an effective method for eliminating individuals of Salix x rubens, in order to provide technical support for the species eradication in São Joaquim National Park (Santa Catarina, Brazil) as well as for its management in other protected areas. An experiment with a four-treatment block design was set up in an area with a dense patch of willows inside the park. The treatments were: (1) mechanical control only; (2) mechanical control and application of a 2% Triclopyr-based herbicide; (3) mechanical control and application of a 3% Triclopyr-based herbicide; and (4) mechanical control and application of a 4% Triclopyr-based herbicide. The trees subjected to the treatments were monitored for nine months after the experiment was set up. The most suitable method for eradication and control initiatives of the invasive hybrid Salix x rubens is the combination of mechanical control with the immediate sequential application of Triclopyr-based herbicide at a concentration of 2%. The mechanical control technique should not be used in isolation to control Salix x rubens, given the high rate of ineffectiveness, with more than 80% of individuals resprouting. The definition of an effective control method has made it possible to eradicate invasive willows in São Joaquim National Park. However, for the results to be expanded beyond the boundaries of the protected area, it is essential that production systems in which invasive species are used are implemented with management measures that contain the expansion of these species or their replacement by native species.