Assessing Landscape Fragmentation: A Composite Indicator

Abstract

The assessment and management of landscape fragmentation (LF), i.e., the subdivision of the habitat into smaller and more isolated patches, can benefit from the adoption of a composite indicator explaining, in a unique measure, the various concerns involved. However, the use of composite indicators may be affected by lack of data, subjectivity in algorithm design, and oversimplification connected to reduction to just one index. In these cases, the findings obtained might not provide the researcher with reliable information. In this paper, we design and apply the Composite Indicator of Landscape Fragmentation (CILF), a metric resuming three indicators concerning the effect on LF of transport and mobility infrastructures, human settlements, and patch density per se. The application concerns the measurement of LF spatial pattern and dynamics from 2003 to 2008 of 51 landscape units in the island of Sardinia (Italy). We considered a complete spatial data set, chose the generalized geometric mean as aggregation algorithm, and verified its robustness via sensitivity analysis of the results. We found that, in 2003 and 2008, the CILF spatial pattern shows higher values in coastal areas and has varied randomly, i.e., without a consistent tendency to converge to, or diverge from, a mean value. Overall, we demonstrate that the CILF is a powerful instrument for monitoring LF in Sardinia and advocate that it can be further implemented, following the same methodological framework, by extending the pool of indicators considered and assessing a weighted version of the composite indicator.

Revisiting the Concept of Quietness in the Urban Environment—Towards Ecosystems’ Health and Human Well-Being

“…However, several inconsistencies among indicators produce results that are hard to decipher. Consequently, the identification of the appropriate indicators and their combination in a new composite indicator [ 86 ] is presented below.…”

To Weight or Not to Weight, That Is the Question: The Design of a Composite Indicator of Landscape Fragmentation

“…The experimented method is a complement of the framework presented by De Montis et al [10], who build, apply, and evaluate the robustness of the composite index of landscape fragmentation (CILF) with respect to the volatility of the ranking of 51 landscape units (LUs) established by the Regional Landscape Plan of Sardinia (RLP) [34]. De Montis et al [10] (i) considered a complete spatial data set, which consisted of human settlements and transport and mobility infrastructures (roads and railways), (ii) applied the generalized geometric mean (GGM) as aggregation algorithm, and (iii) performed a sensitivity analysis of the findings to assess the robustness of CILF.…”

“…CILF is designed as a three-indicator unweighted composite, according to the scheme proposed by the Organisation for Economic Co-operation and Development (OECD) [35] and Nardo and Saisana [5]. The scheme includes the following steps: theoretical framework, variables, normalization, aggregation, and robustness and sensitivity [10]. Since we now focus on a weighted release of the CILF, we add a new step concerning the assessment of values representing the importance of the indicators.…”

“…In this case, we chose the min-max transformation rescaling the original values into figures calculating the distance from the minimum normalized with respect to the range of the original indicator. We selected this model because it was chosen by De Montis et al [10] for designing the baseline release of the CILF.…”

“…The indicators of LF provide a useful indication to effectively addressing green-based urban and regional management and planning. In a scientific panorama, in which contributions on composite indicators of LF are still rare, De Montis et al [10] propose the composite index of landscape fragmentation (CILF). CILF combines three LF indicators bearing the same importance (i.e., weight)-the infrastructural fragmentation index (IFI), the urban fragmentation index (UFI), and the mesh size density (S eff ).…”