Salix × rubens invasion

The aim of this project is to understand willows’ population structure and which factors are involved in the invasion process.

Willows (Salix spp.) are important tree invaders worldwide. Salix × rubens Schrank is a hybrid species originated from the crossing of S. alba L. and S. fragilis L. This species has a single, highly branched trunk and grow more than 15 m in height. S. × rubens is dispersed by wind and water and vegetatively, through woody cuttings. Willows of the Salix alba–Salix fragilis complex are native to western Eurasia and represent typical invaders of floodplain ecosystems worldwide. S. × rubens was introduced in the highlands of southern Brazil in mid-20th century by Italian immigrants due to its wood elasticity and durability to be used as rope for tying grape vineyards. The species adapted well in the region, has become a naturalized species and nowadays is being used for basketry and wicker culture. In Brazil, it has been alleged that the species is not invasive and could even be used for ecosystem restoration – especially near watercourses. However, several reports on the invasiveness potential, invasion and impacts of willows – including S. × rubens – worldwide have likely been ignored. Despite its economic importance, the invasive property of S. × rubens and its possible detrimental effects on Brazilian ecosystems have never been addressed. In this project we are reporting the occurrence and invasion of S. × rubens in the highlands of southern Brazil, in both protected and non-protected areas. This is the first report drawing attention to the invasion of S. × rubens in Brazil, which sometimes forms pure stands along rivers and floodplains. Additionally, we are providing advices on control actions that can be used to control the invasion of this species and instructions for its cultivation in order to decrease its invasiveness.

This project is being developed together with Prof. Dr. Michele de Sá Dechoum and Dr. Sílvia R. Ziller.