INTEGRATED ASSESSMENT OF GEOMORPHOLOGICAL AND VEGETATION DYNAMICS IN A COMPLEX DUNEFIELD. CAPO COMINO CASE STUDY (NE SARDINIA, ITALY).
Creators: name: BALDUZZI, ILEANA
Publisher: name: Universit� degli Studi di Milano
Year: 2012

description: The coastal environment is increasingly subject to utilization and anthropogenic disturbance. Currently a large proportion of the worldwide human population lives close to the coastline and this has led to the modification ? and often the deterioration ? of many previously intact coasts and ecosystems. In particular, the marketing of coastal recreation has increased drastically during the last century obliterating many natural systems. As a result, many coastal systems of the world are in advanced stages of degradation (e.g. with the elimination of native and endemic species and the introduction of the exotics, or the erosive processes induced by human modification of the natural environment, in addition to the natural erosion to which coasts are exposed (Pranzini and Rossi, 2000). In the worst cases, coastal ecosystems have been completely removed in the process of providing living space for the encroaching human population. Dunes, beaches, coastal wetlands and salt marshes are generally considered as ecosystems at risk of loss as they are of high potential economic value or sources of biodiversity for coastal management schemes (e.g. biodiversity protection, ICZM protocols following the Barcelona protocol, 1978). The scientific investigation and understanding of natural processes in coastal ecosystems forms the basis of appropriate conservation and protection activities. The present study investigates the development of an integrated methodology for the characterization of costal dune systems. It aims to produce a general overview of the Capo Comino landscape and its evolution to aid strategic planning decisions for enhancing the environmental sustainability of this natural system. Focus has been given to the most relevant elements of the dunefield, such as its morphological aspect, the influence of the climate on its evolution and the distribution of vegetation. A preliminary study of the general setting of the dunefield area allowed the development of a novel procedure for monitoring the dunes, integrating remote sensing strategies, in-situ measurements and data organization using geographical information systems (GIS). The phases of this project may be summarized thus: - Review of the existing literature Coastal dunes have a worldwide distribution and they are characterized by a variety of forms exhibiting successional changes in geomorphology and ecological associations. The central topic for this phase of the research was the analysis of the studies focused on spatial and temporal variation in morphology, the sequences of biological succession in dune types and their adaptation to environmental stresses. From the morphological point of view, coastal dunes are highly variable in form and dimensions and their current aspect is the consequence of stabilization and destabilization processes (Nordstrom et al., 1991; Psuty, 1997, 1999; Hesp, 2004, 2006; Martinez and Psuty, 2004). The main morphological constraints for their development are related to sediment supply, wind conditions, stabilizing vegetation and human interaction. Furthermore, in coastal environments the dichotomy between the dunes and the beach is a very significant factor. With regard to vegetation, succession on coastal dunes has been the focus of many researches starting around a century ago (initial studies were carried out by Steinheil in 1832 and Cowles in 1899). In the present study vegetation associations and their distribution form the main topic, using the phytosociological method. - Identification of the available information for the study area The state of knowledge for the local study area was determined from published sources. Further data such as aerial and satellite images were evaluated and the vegetation analysis was carried out based on the existing literature that describes the main associations of Mediterranean coastal dune environments (G�hu, 1986; G�hu et al., 1984; G�hu and Biondi, 1994a, 1994b, 1995; Biondi 1999, 2007) and, in particular, of Sardinian coasts (Arrigoni, 1996; Bartolo et al., 1992; Biondi et al., 2001; Biondi and Bagella 2005; Filigheddu and Valsecchi, 2001). - General setting of the study area Investigation of the geology and geomorphology of the area, the wind-wave climate and bioclimatic indices were undertaken. Remote sensing analyses provided an essential overview of the general evolution and morphological complexity of this sector. Morphological and vegetation analyses were carried out on the two principal physionomic units of the coast: the dunefield and the beach. Results of vegetation data allowed a more precise delimitation and spatial distribution of plant associations and the characterization of two new sub-associations. A bathymetric survey including the collection of seafloor sediment samples were also carried out for the characterization of the nearshore system. All collected data and spatial analyses were ultimately implemented into a GIS, thereby allowing cross analysis of the information stored in the geodatabase to obtain both a qualitative and quantitative description of the landscape and the main morphological and vegetation characteristics of the environment. - Monitoring program The procedure integrates morphological and vegetational data - with several sedimentological considerations ? in order to test a novel and readily applicable procedure for coastal dune monitoring. Three field measurement campaigns were carried out during the PhD program. This included measurements of the main geomorphological features with the integration of vegetation distribution along specific transects. Samples of the sediments of the beach and dunefield were collected in order to give further information concerning the grain sizes and the aeolic transport of sand. This research demonstrates that the dynamic processes and disturbances are well recognizable along transects. Therefore it is possible to monitor the general status of a study area using a small number of geomorphological and vegetation profiles. This integrated methodology promises a precise, effective and rapid procedure for the monitoring of coastal dunefields.