Drones and GIS database to monitor anthropogenic threats to dunes

The general objectives of the LIFE REDUNE project are the ecological restoration of the natural coastal zone, the reduction of negative human impacts on habitats and species and the integration of tourism with the conservation of the natural heritage, in an area - the northern Adriatic coast - where tourism represents one of the main economic activities and sources of income.

The dune systems involved in the LIFE REDUNE project are located in a tourist area, close to well-known seaside resorts that are very popular during the summer season.

For example, in the municipality of San Michele al Tagliamento in 2017 the tourist flow was 5,722,191 overnight stays. Despite the innate value of dune ecosystems for both human well-being and biodiversity, the relevant habitats have been subject to a long history of unsustainable exploitation and mismanagement.

While on the one hand tourism represents one of the most important elements of the regional economic system, on the other hand it represents the main threat to the conservation of dune systems. This is mainly due to a general lack of awareness of the environmental problems associated with coastal dunes, which include habitat loss, the spread of invasive alien species and habitat degradation due to tourism and recreational activities, as major threats. As a result, both the biodiversity of dunes and the related ecosystem services they provide are negatively affected, with the result that native species are threatened and habitat resilience is reduced.

Intense anthropogenic pressure, coupled with a lack of ecological awareness, is compromising not only the natural and ecological value, but above all the distinctive and identifying elements of the landscape that constitute one of the factors for tourist attraction..

Two and a half years ago, an initial series of monitoring and inspections was carried out to explore the existing ecological systems and draw up an initial list of habitats present in the four project sites, with particular reference to xerophilous habitats. Since then, the project partner European Project Consulting (EPC) has made several visits to all the sites, acquiring aerial images using a drone, a remotely piloted aircraft.

The processing of the data allowed the creation of a three-dimensional digital model of the terrain(DTM) with a resolution of 25 cm and updated photomaps of the working areas with a pixel resolution of 5 cm on the ground. From these printouts, a vector rendering of surveys, digital orthophotoplans and digital terrain models was produced. Subsequently, photo interpretation and video digitisation of the perimeters of the individual habitat polygons were created. This first draft of the map made it possible to identify the spatial discontinuities between the habitat types and to define the network of access routes to the sea resulting from uncontrolled trampling.

The attribution to the various habitat types was carried out by the University of Venice Cà Foscari through further on-site inspections and field surveys and the integration of information from vegetation surveys.

The analysis of the digital orthophotoplans led to the production of:

  1. a) an initial mapping of routes, walkways, tracks and areas with the highest tourist load;
  2. b) location of the discontinuity of the mobile dunes that should protect against marine ingress
  3. c) Habitat maps, with specific reference to the project and surrounding areas.

All maps were produced at a scale of 1: 500. This information was included in a GIS (Geographic Information System) geodatabase, which is an integral part of the LIFE REDUNE project and is periodically updated. GIS is a computer system for acquiring, storing, controlling and displaying data related to positions on the Earth's surface. By linking seemingly unrelated data, GIS can help to better understand spatial patterns and relationships.

In the first phase of the LIFE REDUNE project, this high-resolution mapping enabled the identification of the complex micro-mosaic in which the same habitat is present in the same polygon at different conservation levels, proportional to the level of disturbance. This led to the definition of the fine location and quantitative composition of the native species to be included and the location of prohibited areas.

In the final phase of the LIFE REDUNE project, this system will make it possible to monitor and measure the effectiveness of the interventions carried out by the project.