Status and changes of ground vegetation at the CONECOFOR plots, 1999 - 2005

Abstract

The vegetation dataset (1999-2005) of the CONECOFOR network is analyzed in the paper, to produce a present-day status and evaluation of changes in a sub-set of Permanent Monitoring Plots (PMPs). Descriptors such as mean number of species (community and population scale), diversity indices and species turnover were selected. Each PMP was investigated to evaluate: (i) type and direction of variations; (ii) significant changes of species indicator values. At the community level, significant variations in richness occurred in sites affected by recent anthropic or natural disturbances. In few PMPs directional changes can be observed; in most of cases a typical fluctuation pattern (more or less regular) was detected. The use of a priori reference standard (RS) supported the interpretation of changes. At finer scale (population level), annual richness variations are frequent but of minor importance. Higher values of species turnover occurred in communities under intense dynamic processes, interested by disturbance or influenced by neighboring communities. The abundance of nitrophilous species was consistent in beech forests, while the contribution of acidophilous species was not important. Moreover, our results suggest that: (a) the data collected at the community level seem more sensitive to describe important changes at the forest stand level; (b) a strong relationship is present between plant diversity and the forest dynamical state. The inherent non-linear dynamics of forest regeneration processes emphasizes the needs of long-term datasets for detecting the plant diversity responses to environmental changes.

Keywords

• forest monitoring
• long term studies
• species diversity
• Reference Standard
• species richness
• species turnover
• species indicator values.