Piera Di Marzio

Monitoring Natura 2000 habitats: habitat 92A0 in central Italy as an example

The evaluation and the subsequent monitoring of the conservation status of habitats is one of the key steps in nature protection. While some European countries have tested suitable methodologies, others, including Italy, lack procedures tested at the national level. The aim of this work is to propose a method to assess the conservation status of habitat 92A0 (Salix alba and Populus alba galleries) in central Italy, and to test the method using data from the Molise region. We selected parameters that highlight the conservation status of the flora and vegetation in order to assess habitat structures and functions at the site level. After selecting the parameters, we tested them on a training dataset of 22 unpublished phytosociological releves taken from the whole dataset, which consists of 119 releves (49 unpublished releves for the study area, and 70 published releves for central Italy). We detected the most serious conservation problems in the middle and lower course of the Biferno river: the past use of river terraces for agriculture and continual human interventions on the river water flow have drastically reduced the riparian forests of Molise. Our results show that in areas in which forest structure and floristic composition have been substantially modified, certain alien plant species, particularly Robinia pseudoacacia, Amorpha fruticosa and Erigeron canadensis, have spread extensively along rivers. In the management of riparian forests, actions aimed at maintaining the stratification of the forest, its uneven-agedness and tree species richness may help to ensure the conservation status, as well as favour the restoration, of habitat 92A0.

Differentiation and hybridization of Quercus frainetto, Q. petraea, and Q. pubescens (Fagaceae): insights from macro-morphological leaf traits and molecular data

Macro-morphological leaf traits and genetic assignments were combined to study the differentiation and hybridization of three sympatric and inter-fertile white oak species (Quercus frainetto, Q. petraea, and Q. pubescens). The sampling was performed in a single forest stand of central Italy (Mount Vairano) in which the cover percentages of each of these three oak species were almost equal. The individuals classified as pure species and the hybrid individuals were divided into two subsets (A and B) which were subsequently statistically analysed. The results regarding the subset of pure individuals showed a clear separation between the three species on the basis of differences observed in the following leaf traits: basal leaf shape, petiole ratio, petiole length, number of intercalary veins, pubescence of the petiole, leaf area, number of lobes, lamina length, and percentage of venation. Regarding the subset of hybrid individuals, as expected, a wider pattern of leaf traits compared to that exhibited by the pure individuals was observed. The leaf traits of the pure species that had provided the greater genetic contribution in the hybridization process were easily identifiable. Quercus pubescens and its hybrids exhibited a higher degree of leaf traits variability when compared with those observed for Q. petraea and Q. frainetto.

Using vegetation dynamics to face the challenge of the conservation status assessment in semi-natural habitats

The conservation of semi-natural habitats represents a primary challenge for European nature conservation due to their great species diversity and their vulnerability to ongoing massive land-use changes. As these changes rapidly transform and phase out semi-natural habitats, conservation measures should be prompt and specifically focused on a sound assessment of the degree of conservation. Here we develop a methodological strategy for the assessment of the degree of conservation of semi-natural grasslands based on well-defined criteria rather than on expert opinion. Through mixed effect models, we tested ten potential indicators, encompassing proxies of species composition, habitat structure, and landscape patterns, against a measure of compositional change from habitat favourable condition, i.e., an inverse proxy of conservation status. This measure derives from the re-visitation of 132 sampling units historically sampled between 1966 and 1992 along the Apennines. The compositional change was quantified as the dissimilarity between historical habitat species pools and the composition of current communities. The compositional change was significantly related to the number of habitat diagnostic species and the relative cover of woody species with opposite sign (positive and negative, respectively). We classified and combined the classes of these two indicators in each sampling unit to assess the habitat degree of conservation at the plot and at the Natura 2000 site level. At the plot level, our assessment was in good agreement with the occurrence of species of conservation concern. On the other hand, at the site level, our assessment was not always harmonic with the habitat conservation assessment officially reported for the site investigated.