Massimo Iannetta

Satellite estimate of grass biomass in a mountainous range in central Italy

One of the main problems in managing ranges used for extensive pastoralism is the difficulty of obtaining reliable estimates of grass biomass over very large areas. Estimates of grass biomass are useful as an indicator of both available forage and risk of soil erosion. Nevertheless, large scale field measurements are expensive and time-consuming. The use of satellite images may provide a complementary means of estimating grass biomass over very large areas at a reasonable cost. The aim of this study was to test the use of Landsat satellite data for estimating grass biomass in a mountainous range in central Italy used primarily for sheep breeding. During each of four ground campaigns carried out over two years, grass was cut and its biomass measured in 60-90 test plots. Four Landsat images taken simultaneously to the ground campaigns were processed to obtain several vegetation indexes calculated for each ground test plot. The vegetation indexes showed significant correlations with measured grass biomass. The Normalized Difference Vegetation Index (NDVI) provided the most accurate estimate of grass biomass. When data for each of the four ground campaigns were analyzed separately, correlations for early summer campaigns were higher than correlations for late summer campaigns, indicating that when the ratio of dry/green biomass increases, satellite estimate becomes less accurate. Overall, our results show that satellite data can provide a useful source of biomass information for the management of large ranges.

Coastal dune systems and disturbance factors: monitoring and analysis in central Italy

This study describes the conservation status of dune systems in relation to disturbance factors in the coastal stretch of the Viterbo province, Latium Region, Italy. Particular emphasis was given to the bioindication value of plant communities and their sequence. Each plant community was considered as a “habitat” in accordance with Annex I of the Directive 92/43/EU. Stress factors, such as sand dynamic and erosion, and anthropogenic pressures, such as trampling and bathing settlements, influence the sequence of habitats and weaken the system of relations that makes these coenoses to occur in extreme conditions. The choice to carry out surveys along wide transects, recording different data, allowed to explore the use of habitats as bioindicators. Comparing sites characterized by the same extension in a homogeneous area, it was possible to expand the use of canonical correspondence analysis (CCA) as a tool to correlate habitat composition and disturbance factors. The application of CCA showed a high correlation of degradation and habitat loss with coastal erosion, trampling and presence of waste. Furthermore, floristic surveys allowed the application of different biodiversity indices to quantify species richness of sampled areas. The conservation status of the sites investigated was found to be diverse, from the total disappearance of the mobile dune habitats to their complete sequence. The proposed methodology has been useful to fulfill the objective of the work and is applicable to other case studies in the Mediterranean.