ABSTRACT
At some point in their history, most forests in the Mediterranean Basin have been subjected to intensive management or converted to agriculture land. Knowing how forest plant communities recovered after the abandonment of forest-management or agricultural practices (including livestock grazing) provides a basis for investigating how previous land management have affected plant species diversity and composition in forest ecosystems. Our study investigated the consequences of historical "land management" practices on present-day Mediterranean forests by comparing species assemblages and the diversity of (i) all plant species and (ii) each ecological group defined by species' habitat preferences and successional status (i.e., early-, mid-, and late-successional species). We compared forest stands that differed both in land-use history and in successional stage. In addition, we evaluated the value of those stands for biodiversity conservation. The study revealed significant compositional differentiation among stands that was due to among-stand variations in the diversity (namely, species richness and evenness) of early-, intermediate-, and late-successional species. Historical land management has led to an increase in compositional divergences among forest stands and the loss of late-successional forest species.
Subject(s)
Biodiversity , Forests , Plants , Agriculture , Ecosystem , Mediterranean RegionABSTRACT
The essential oil has been studied of leaves of Senecio coincyi Rouy, an endemic species of Spain restricted to a very small area of the Central Iberian Peninsula. Samples from five locations were obtained by hydrodistillation and extraction and analysed by gas chromatography-mass spectrometry. The main compound was 1-tridecene (28.1 +/- 8.5%). The presence of unsaturated hydrocarbons (1-undecene, 1-dodecene and 1-tridecene) seems to indicate a chemotaxonomic relationship between Senecio coincyi and S. congestus.
