Civil society can play a relevant role in supporting local environmental management, as volunteer efforts can be carried out at low cost and therefore be sustained over time. We present in this paper the assessment of the effectiveness of a volunteer program for the control of invasive pines in a protected area (PA) in a coastal zone of southern Brazil. Volunteer work has been ongoing for 8 years and the current state of invasion was compared with three simulation scenarios of species distribution that considered suitable habitats for pine invasion. Our results suggest that management actions have been effective. In the absence of any control efforts, pine trees would cover a high percentage of suitable habitats within the PA. Eliminating adult pine trees that function as seed sources and not allowing the next generation to reach maturity has been an efficient control strategy that has led to changes in the population structure of pines in the PA. Reaching neighboring private property owners is key for the future effective control of pines in the area, as all sources of pine seeds need to be eliminated. The approach used in our study may be applied to broader spatial scales to provide a baseline for management efforts needed to effectively control non-native invasive species.