The potential of the National Forest Inventory to assess the state of conservation of forest Habitat types of Community Interest: new challenges to comply with biodiversity conservation policies

Abstract

Assessing the state of conservation (SC) of the Habitat types of Community Interest (HCIs) is a requirement of the Habitats Directive (92/43/CEE) that seeks to safeguard their biodiversity. Thus, extensive knowledge about the distribution, structure and function (S&F) and conditions of these habitats is needed. The National Forest Inventory (NFI) can represent an adequate and precise tool to characterize forest habitats, by monitoring around 100 parameters every ten years in more than 90 000 plots distributed throughout Spain. The aim of this work is to assess the suitability of the NFI as a data source to report on the SC of the S&F parameter of the 22 Spanish forestry HCIs. For this, the representativeness of each HCI in the NFI was evaluated and a total of 15 diagnostic variables of the S&F parameter were estimated in the plots categorized within each HCI. The results showed that most of the forestry HCIs in Spain are well represented in the NFI but that their SC of the S&F parameter was mainly 'unfavourable-inadequate' (15 HCIs) and 'unfavourable-bad' (6 HCIs), which agrees with previous evaluations. Specifically, forests of Ilex aquifolium (9380) and (9380) and Quercus suber (9330) showed the highest percentage of plots in ‘favorable’ status, in contrast to palm groves of Phoenix (9370) and Q. ilex and Q. rotundifolia forests (9340). This work presents a standardized and optimized approximation to evaluate the SC of the S&F parameter of forest habitats whose easy implementation could guide European strategies for their monitoring and conservation.