Plantas Invasoras na Floresta com Araucária: novas espécies, novos impactos, novos desafios

ZALBA, SERGIO M.; MONDIN, CLAUDIO A.; ZILLER, SÍLVIA R.

Floresta com Araucária: Ecologia, Conservação e Desenvolvimento Sustentável

Editora Holus

Lugar: Ribeirão Preto, SP, Brasil; Año: 2009; p. 267 - 272

Dispersion of species away from their original geographical ranges is one of the most intense environmental consequences of human activities on Earth. A portion of the introduced species manages to establish self-sustaining populations and to advance over natural environments in the new locations; these species are known as alien invasive species (IAS). The great majority of them are moved purposely by man for a variety of reasons, while another set spreads unconsciously in association to human transport and commerce. They alter biological communities and the whole landscape, change nutrient cycling and modify the frequency, seasonality and intensity of disturbances. The effects of IAS on biological communities are so intense that they are considered the second cause of biodiversity loss at the global scale, being also responsible for significant impacts on human health and economy. Despite the seriousness of this problem, it has only recently been affectively addressed in South America. This chapter presents a preliminary survey of alien plants invading Araucaria forest in Southern Brazil together with information on their antecedents as invaders in other ecosystems, most probable causes of introduction and impacts. It also highlights significant issues for their effective management. Our survey includes 33 invasive plants belonging to 21 families; being Poaceae the most represented one. One third of the species came from Asia and about a quarter from Africa. The most cited species in literature are Eriobotrya japonica (Japanese plum) and Hovenia dulcis (Chinese raisintree), followed by Pinus taeda (Loblolly pine) and Hedychium coronarium (White ginger). Almost all the species cited as invaders in the Araucaria forest has antecedents as invaders in other countries. The main cause of introduction of alien plants to Southern Brazil has been their use as ornamental (63.6 %) followed by timber and fodder production. Data on species abundance indicates that in most of the cases invasion processes are in their initial stages, pointing the opportunity of addressing the problem in the short term. Among the research and management priorities for the region are: 1- detect sleeping species, that is introduced plants that have not yet managed to invade natural ecosystems, and start prevention measures, 2- develop research and extension strategies directed to explore and promote the use of native species for economic activities, 3- prevent the spread of species already invading other forest ecosystems in Brazil like Persea americana L. (Avocado) e Citrus limonia (Rough lemon), 4- strengthen regional initiatives among different countries of the region and coordinate trans-boundaries management strategies. Biological invasions are an expanding problem, and their impact becomes almost irreversible beyond certain threshold. It needs research, awareness and concrete political action. In the case of the Araucaria forest there is an opportunity to intervene in order to avoid significant problems in the future, and raising concern in academic, political and productive arenas appears as an immediate challenge in this direction.