Plant species diversity in Mediterranean old-growth forests: A case study from central Italy

Abstract

To investigate the differences in understorey composition and diversity between old-growth and managed forests, we analyzed an old-growth and a managed beech stand in the same area displaying similar abiotic features. We considered variations in understorey species composition and richness. The sampled understorey species were characterized in terms of functional traits, Ellenberg's indicator values and taxonomic distinctness; next, we calculated four different pairwise plot-to-plot dissimilarity matrices based on species composition, functional traits, Ellenberg's indices and taxonomic distances. We applied a permutational multivariate extension of ANOVA to test whether the forest stands significantly differ in the considered features. Indicator values of all plant species in managed and old-growth stands were evaluated.

The old-growth forest had a higher species richness; permutational analysis of variance showed significant differences between the two stands in plant species composition, functional traits, Ellenberg indices and taxonomic distances. Indicator species analysis highlighted 14 indicator species for the unmanaged stand, while only 3 indicators were found for the managed one.

The results suggest that forest management determines ecological differences that strongly affect plant species composition.

The knowledge of natural stands dynamics could allow development of new approaches and practices in forest management focusing on biodiversity conservation.

Keywords:

• Ellenberg indices
• forest management
• functional traits
• permutational multivariate analysis of variance
• taxonomic diversity

Acknowledgements

We thank the Scientific Service of Abruzzo, Lazio and Molise National Park for collaboration and for permission to conduct this study. We are also grateful to Carlo Ricotta for assistance with the statistical analysis, Fabio Lombardi and Marco Marchetti (Università degli studi del Molise) for providing the structural data, and to Francesco Maria Sabatini and Giuseppe Di Marco for helping us during fieldwork, and Michela Marignani for useful comments and a critical revision of the manuscript.