Estimation of plant diversity in a forested mosaic landscape: the role of landscape, habitat and patch features

In Europe traditional mosaic landscapes have been experienced dramatic changes through either intensification or abandonment of land use. Both trends are thought to affect plant diversity in forest areas. To evaluate the sustainability of specific forest systems we need approaches for 1) assessment of the contribution of different land use systems for plant species diversity and 2) identification of habitat and landscape features that lead to patterns of biodiversity. Despite good theoretical knowledge about determinants of plant species richness in mosaic landscapes, validations based on surveys are scarce. We conducted a case study in a forested landscape in Central Portugal, with an area of 130 km2, were the already referred drivers of change have been shaping the landscape in the past decades. We used aerial photo-interpretation to identify land cover/use types; and a multi-scale field inventory to assess plant species diversity. Diversity measures were calculated at patch, habitat and landscape level. Hypothetical influencing factors were also categorized at patch, habitat and landscape. Influencing factors were assessed by means of metrics that reflect structure and dynamics of the landscape at patch, habitats and landscape level. The relationship between species diversity and influencing factors was investigated by means of multiple linear regression models. Results showed significant differences between cultivated forests in what plant diversity is concerned. The main influencing factors were identified. The evidence and indicatives values found and their interest for the development of sustainable landscape management is discusse