A phytosociological review of siliceous sedges in C-W Spain and their state of conservation based on diversity indices

A study was made of waterlogged areas in C-W Spain, and revealed the presence of the alliance Genistion micrantho-anglicae, and a series of associations belonging to Isoeto-Nanojuncetea included in habitat 3170*. This work describes the new association Ericetum scopario-lusitanicae in Genistion micrantho-anglicae, and assigns it to habitat 4020*. Due to the importance of these areas, we study their state of conservation and analyse their diversity by applying Shannon’s index and establishing a relationship between the characteristic and companion species abundance in the community. The analysis of the diversity and state of conservation of the sampled plots at a global scale over the whole territory shows a conservation level of VmCa-VmCo > 0. However the study of individual plots reveals a trend towards the transformation of heathland into plant communities of Molinia caeruelea, Junxcus acutiflorus, Pteridium aquilinum and Rubus ulmifolius.