Questions: we studied old growth beech forest vegetation in Permanent Monitoring Plots
(PMPs) located in Italy, with the following questions: is species turnover the main
component of the observed changes or the present species assemblages is an
impoverished sub-sets of the former ones?; 2) how compositional changes are reflected
by specific plant functional traits?
Location: we selected 4 PMPs (50 x 50 m) of the CONECOFOR network, placed along a
latitudinal and climatic gradient in Italy, from south to north: CALABRIA03, CAMPANIA04,
ABRUZZO01 and VENETO20.
Methods: presence/absence of herb layer species were recorded in 100 permanent
micro-plots of 50 x 50 cm over 12 years (1999-2011). For all sampled species we chose a
set of 8 easy-to-measure functional traits. We compared the persistence, nestedness and
turnover components of compositional changes. The role of plant traits explaining species
persistence were analyzed by classification and regression tree.
Results: Analysis in species diversity reveal antithetical ecological phenomena due to the
diversity and complexity of the 4 different forest stands. ABRUZZO01 and CALABRIA03
show a clear nestedness trends over time with persistent species in ABR01 having higher
seed mass and persistent species in CALABRIA03 having scleromorphic leaves and
mesoporphic leaves, with large below-ground budbank. On the other hand, VENETO20
and CAMPANIA04 exibit a significant turnover trends over the 12 years characterized by
persistent species in VENETO20 having helomorphic leaves, while in CAMPANIA04 large
below-ground budbank and smaller SLA were the most important traits for species
survival.
Conclusion: Fine-scale approach highlight different mechanisms for the maintenance of
species diversity in different complex forest systems driven significantly by specific traits,
influenced by context-dependent factors
