Management priorities for exotic plants in an urban Atlantic forest reserve.
Biological diversity is directly affected by alien species, even though the diagnosed impacts vary with scale. Early identification of the invasion of natural patches is essential for effective conservation actions. We aimed to determine the exotic plant species present inside Fontes do Ipiranga State Park (PEFI), an urban protected area located in the city of São Paulo, Brazil, and their relative proportions of occurrence in the native forest. Our goal was to use these data to assess their invasion status according to specific literature and to define management priorities for them. Therefore, we surveyed the presence of exotic plants within the canopy layer and understory of three native forest areas with different levels of disturbance. We found ten exotic plant species. The species found in both strata (60%) were considered non-dominant ruderal. We assessed the density:coverage ratio to try to distinguish groups of priority, and found Livistona chinensis, Archontophoenix cunninghamiana, and Syzygium jambos to be classified as high priority for management. The early stage of the invasion process at PEFI indicates it is an area of high conservation value, and so we provide recommendations for management priorities prior to severe changes in the composition of the natural plant community.