Avaluació de la vegetació al projecte de restauració de l'Illa de Gallifa o del Sorral (riu Ter a les Masies de Voltregà, Osona)

Abstract

In this study we mainly conduct an assessment of the vegetation of the island of Gallifa or Sorral ( Location: River Ter, Masies de Voltregà, Osona), after the restoration project which took place in the island. This project was part of a bigger project to restore vegatation which currently aims at the riverbank of the river Ter, the project was led by Centre d’Estudis dels Rius meditarranis – Museu del Ter. The island of Gallifa or Sorral is one of the few fluvial islands which are to be found in the upper-mid section of the river Ter. It is tangible evidence that the geomorphological activity of the Mediterranean rivers, along their meanders and floodable areas, make up habitats of great ecological potential. Thus, in 2010 there was a felling of the artificial poplar (of Populus deltoides) plantation found on the Island. From then on, they started a project of restoration to recover the adequate vegetation of the area. To do so, they planted native trees of the area; they followed previous experimental design. The main objective of the project was to see in the long run whether it was better to plant vegetation or to let it grow on its own. This experimental design consisted of dividing the area into pieces of land which would then be restored. They just planted trees in half of those areas. In the pieces of land where they planted trees, they chose different species of trees, depending on the relative distance to the phreatic water level. We have looked at the evolution of the survival of the planted trees, the differences between the native and exotic species and the pieces of land with and without planting schemes. We have compared the abundance of native trees, especially the white willow (Salix alba), taking into consideration the different types of habitats. Generally, after 5 years, the riverbank forest has seen progressive improvement after the forest restoration were conducted. Additionally, even though the richness of species has not varied throughout the past 5 years, the plant structure in the riverbank forest has improved outstandingly, especially in the pieces of land where measures were taken and trees planted