# GI Guidelines for the Metropolitan City of Cagliari (Italy): A Method for Implementing Green Areas
## 4 Application and Results: A Proposal of GI Guidelines for the Metropolitan City of Cagliari
### Context Analysis
Basins 'Sulcis' and 'Campidano' include the MC of Cagliari and are significantly affected by hydrogeological risk. In these areas, a poor adaptation to hydrogeological risk has emerged. Basin 'Sulcis' is the area most affected by the risk of landslides. In areas affected by hydraulic and landslide risk, GIs are able to mitigate the risk. In this regard, the hydrogeological regional plan suggests the use of non-structural and naturalistic structural engineering measures based on GIs components [38]. In Figure 3, the landslide hazard (Hg) ranges from Hg0 (lowest hazard) to Hg4 (highest hazard), while the flood hazard (Hi) ranges from Hi1 (lowest hazard) to Hi4 (highest hazard). According to the strategic plan [34], the inclusion of nature-based solutions -such as GIs- in planning tools, and their practical implementation, are useful solutions against climate change and hydrogeological vulnerability, which are reported as the main threats to be tackled. Finally, we consider the landscape fragmentation issue, as it can affect biodiversity and ecosystem continuity [39; 40]. We consider the degree of landscape fragmentation due to urbanized areas and transport and mobility infrastructures, which was calculated by applying a composite indicator [41; 42]. The composite indicator of landscape fragmentation (CILF) consists of three indicators, which consider the effect of roads and railways, human settlements, and patch density on landscape fragmentation. Specifically, CILF combines the Infrastructural Fragmentation Index (IFI), the Urban Fragmentation Index (UFI), and effective mesh density (S\({}_{\text{eff}}\)) [39; 41; 42; 43; 44]. [PERSON] et al. point out that \"the use of the CILF is intended for analytical and decision-making purposes, as it allows a simplification in the interpretation of a unique metric\" [41]. In addition, the use of a composite indicator can provide \"a system able to support policymakers, who are able to visualize results and maps via an intuitive graphic representation [and] a wise reading of the CILF may support planners and policymakers in addressing the most efficacious measures for managing LF [... ]\" [41]. In Figure 3C, according to the values of CILF, the darker the color, the more fragmented the landscape. The CILF has been calculated for each landscape unit defined by the RLP of Sardinia [45]. Table 3 reports on CILF values measured for the landscape units included, also partially, in the MC. The composite indicator varies in the range 0-1: the higher the value, the higher the degree of landscape fragmentation. Landscape Unit 'Golfo di Cagliari' is the most fragmented (CILF = 0.5). Landscape Unit 'Basso Campidano' also shows moderate fragmentation (0.37). In this context, the adoption of GIs as an ensemble of ecological corridors linking otherwise isolated habitat patches can contribute to the reduction of landscape fragmentation. This spatial analysis might be relevant to regional (and sub-regional) planning, as it focuses on key issues, such as: the conservation of biodiversity in Natura 2000 sites; an overview on the areas affected by geological and hydrogeological risk, where countermeasures have to be defined; and landscape fragmentation, which hinders the movement of \begin{table}
\begin{tabular}{c c} \hline \hline
**Landscape Unit (Code)** & **CILF** \\ \hline
31 & 0.04 \\
28 & 0.05 \\
29 & 0.06 \\
2 & 0.10 \\
33 & 0.14 \\
27 & 0.15 \\
30 & 0.37 \\
1 & 0.50 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Composite indicator of landscape fragmentation (CILF) by RLP landscape unit included in the MC of Cagliari. specific target species between habitat patches, where defragmentation measures could be planned. However, such a spatial analysis needs to be supplemented with information, data, and suggestions provided by the stakeholders involved in the planning process.