Environment: Marche, 9 hectares of natural reserve lost due to coastal erosion

In the last 20 years nine hectares of Bilge Natural Reserve, in the south-eastern end of the Marche region, were lost to the sea due to erosion; moreover, between 1985 and 2012 the area covered with dunes decreased by over 80%, i.e. 40,000 square meters of natural habitat.

This was reported in a study published in the prestigious international journal “Ocean & Coastal Management” by a team of researchers from ENEA, ISPRA, CNR and the University of Camerino. The study, available online in open access until 4 March 2021, analyzes the geomorphological and sedimentological characteristics of the coastal area, ALSO identifying the evolutionary dynamics of the beach-dune system.

According to the researchers, there is also evidence that the river Tronto - which flows in the area and marks the border between Marche and Abruzzo - cannot transport the amount of sand necessary to maintain the balance of the Marche coast any longer, due to the impoverishment of its bed, also caused by extractive activities [1], with damage to the ecosystem and shoreline retreat.

"The methodological approach based on geographical, historical and territorial data crossing and surveys in the field, allows mapping, data and results sharing and replicability and adaptability to other contexts - Sergio Cappucci of the ENEA Department of Sustainability of Productive and Territorial Systems, pointed out - Moreover, it could be an efficient support tool for administrations and institutions involved in the management of sediments for the conservation of the coastal habitat and development of adaptation strategies ".

Starting from the evidences of the study, local authorities have begun to implement actions to mitigate the effects of erosion in the most vulnerable stretches of coast through the so-called "soft beach nourishment",  that is by dredging the sediments from the nearby port of San Benedetto del Tronto, which periodically experiences siltation problems.

This type of intervention allows on the one hand to ensure safe navigation in port areas and on the other hand to safeguard the habitat of the natural reserve, crucial for the management and development of coastal protection strategies. “However- Cappucci concluded- in the long term, interventions aimed at reducing the anthropogenic pressure on the area and increasing the availability of sand will be needed”.

"Thanks to the results obtained, the area underwent the first ecological restoration intervention", Emiliana Valentini of the Institute of Polar Sciences of the National Research Council (Cnr-Isp) said "this made it possible to restore part of the coastal plain [2] to  its natural wetland status ".

"The important findings of this study", Carlo Bisci of Unicam pointed out, "which stems from an over twenty-year collaboration among the University, Municipality of S. Benedetto del Tronto and Sentina Natural Reserve, yielded accurate measurements of the morphology of the emerged beach area and the seabed, as well as the related morpho-evolutionary trends.

Adequate measures are urgently needed to prevent this rare and important wetland area from being submerged by the sea within a few years, also given the poor state of the whole coastal dune areas of the Marche Region ".

"In order to understand the evolution of the coast both in its emerged and submerged portion" Matteo Conti of ISPRA pointed out, "topographic, bathymetric, sedimentological and stratigraphic surveys were conducted analyzing data from 1985 to today, and a geo-database with all the information collected was set up ".

Sentina Natural Reserve, in fact, covers an area of approximately 180 hectares within the Municipality of San Benedetto del Tronto (AP), between the Municipality of Porto d'Ascoli to the north and the river Tronto to the south. A unique landscape alternating water, sand, wetlands and brackish meadows, characterized by rich flora -disappearing in the rest of the Adriatic coast because of anthropization-  which has an important role for migratory birdlife, whose only possibility of coastal rest is on the wet areas of the Po delta and the Gargano.

Sentina is among the 40 italian coastal areas at risk of flooding identified by ENEA in 2019: according to the researchers, in the absence of mitigation and adaptation interventions, by 2100 over 5,600 square km – the size of a region like Liguria - and more than 385 km of Italian coast are in danger of being submerged by the sea due to a rise in the Mediterranean sea level caused by global warming

The following researchers collaborated in the study: Alessio Acciarri, Carlo Bisci, Gino Cantalamessa and Giorgio di Pancrazio of the University of Camerino, Federico Spagnoli and Emiliana Valentini of the CNR and Matteo Conti of ISPRA.

For more information please contact:

Sergio Cappucci, ENEA – Sustainability of Productive and Territorial Systems Department  - email: sergio.cappucci@enea.it

Link: https://authors.elsevier.com/a/1cPNM3RKK-nkgn

Link to the Journal  “Ocean & Coastal Management” (Volume 201, 15 February 2021) [3]: https://www.sciencedirect.com/science/article/pii/S0964569120303793?dgcid=author

Elevation map of the coastal area of the Bilge at 2100:

2100: https://www.enea.it/it/Stampa/File/martinsicuro-tronto.pdf

Video by the Sentina Natural Reserve

[1] Anthropogenic influence on recent evolution of shorelines between the Conero Mt. and the Tronto R. mouth (southern Marche, Central Italy) Acciarri, Bisci, Cantalamessa, Di Pancrazio. (2016) Catena, 146, 545-555.

[2] Valentini E., Conti M. Bovina G., Cappucci S., Gabellini M. (2010). Integrating ecological and hydrological features to assess coastal wetland restoration. In Bottarin R., Schirpke U., Tappeiner U. EURAC book - Analisi spazio-temporali: dinamiche e processi a confronto, Proceedings of XIX SItE Conference, VOL. II, 15-18 September 2009, Bolzano, 57: 113 -122.
http://www.eurac.edu/en/research/mountains/alpenv/projects/Documents/SITE2009_atti_vol2.pdf

[3] Acciarri A, Bisci C., Cantalamessa G., Cappucci S., Conti M., Di Pancrazio G., Spagnoli F., Valentini E (2021) – Metrics for short-term coastal characterization, protection and planning decisions of Sentina Natural Reserve, Italy. Ocean & Coastal Management, 201, 1-16.