Veronica Zumpano

Variations in the susceptibility to landslides, as a consequence of land cover changes: A look to the past, and another towards the future

Land cover is one of the most important conditioning factors in landslide susceptibility analysis. Usually it is considered as a static factor, but it has proven to be dynamic, with changes occurring even in few decades. In this work the influence of land cover changes on landslide susceptibility are analyzed for the past and for future scenarios. For the application, an area representative of the hilly-low mountain sectors of the Italian Southern Apennines was chosen (Rivo basin, in Molise Region). With this purpose landslide inventories and land cover maps were produced for the years 1954, 1981 and 2007. Two alternative future scenarios were created for 2050, one which follows the past trend (2050-trend), and another one more extreme, foreseeing a decrease of forested and cultivated areas (2050-alternative). The landslide susceptibility analysis was performed using the Spatial Multi-Criteria Evaluation method for different time steps, investigating changes to susceptibility over time. The results show that environmental dynamics, such as land cover change, affect slope stability in time. In fact there is a decrease of susceptibility in the past and in the future 2050-trend scenario. This is due to the increase of forest or cultivated areas, that is probably determined by a better land management, water and soil control respect to other land cover types such as shrubland, pasture or bareland. Conversely the results revealed by the alternative scenario (2050-alternative), show how the decrease in forest and cultivated areas leads to an increase in landslide susceptibility. This can be related to the assumed worst climatic condition leading to a minor agricultural activity and lower extension of forested areas, possibly associated also to the effects of forest fires. The results suggest that conscious landscape management might contribute to determine a significant reduction in landslide susceptibility.

A morphogenetic insight into a multi-hazard analysis: Bâsca Mare landslide dam

Slope–channel coupling in geomorphologically active regions represents a topic with numerous implications, from both fundamental and applied perspectives. Landsliding and erosion combine under the influence of the morphostructural and lithological, seismic, climatic, and anthropic factors, and their interaction may materialize in landslide dams, forms which are conditioning the future slope and river morphology and morphodynamics. The proper understanding of the predisposition and preparing and triggering factors in case of landslide dams could provide significant information in the risk analysis, assessment, and management. The occurrence in July 2013 of a landslide dam in the Buzău Mountains (along the Bâsca Mare river), caused by the partial reactivation of a dormant deep-seated landslide, allowed the outlining of the entire agents–forms–processes framework, offering in the meantime the background data for a future multi-hazard assessment. Since the Vrancea seismic region (area that comprises the Curvature Carpathians of Romania) represents one of Europe’s most slope/channel/seismically active regions, the case–study offers important insight information that allows in the meantime the analysis of multi-hazard at a regional scale.

Forest management and future changes to ecosystem services in the Romanian Carpathians

This study investigates consequences of future changes to the provision of ecosystem services (ES) in the Romanian Carpathians. Two 2040 forest management scenarios were compared, using two indicators to describe the gains and losses of ES. Changes in landslide regulation potential were defined as changes to landslide susceptibility. High nature value grasslands characterized biodiversity support. The business as usual scenario results in a 8% lower loss of landslide regulation potential compared to the alternative scenario. It also results in a 29% higher regional net gain of landslide regulation potential. Both scenarios result in the loss of biodiversity support due to their prevalent transition of forest expansion. This type of information is crucial for informing decision makers on the locations of potential gains and losses of future development.

Scenarios of Land Cover Change and Landslide Susceptibility: An Example from the Buzau Subcarpathians, Romania

Since 1990 the Subcarpathians in Buzau County, Romania have witnessed substantial socioeconomic changes and resulting changes in the land cover. Influenced by the interplay of poor economic conditions, land ownership reforms, and institutional difficulties, these changes have been difficult to manage, resulting in a dispersal of built-up areas. Even though, the spatial extent of land cover changes has not reached critical levels as similar areas in the Carpathians, our analysis suggests that in the future the area might experience more extreme land cover changes. Moreover, the litho-structural traits and the high relief energy of the Romanian Subcarpathians favored the occurrence of various types of mass movements, imposing different levels of risk to people, buildings and infrastructure. Increase of human influence in form of expansion of built-up areas in the area could therefore result in slope instability and changes in the temporal and spatial patterns of hydro-meteorological hazards. This study shows, that possible future changes in land cover will not have a major influence on hazards, however risk might increase due to the increased value and number of elements at risk.

Built-Up Area Exposure to Landslides and Related Social Impacts in Molise (Italy)

Open image in new window In central-southern Italy, Molise stands among the most prone sectors to landslide occurrence where mass movements regularly affect towns and villages, causing frequent damages to assets such as infrastructures or houses. For these reasons landslides may influence the life quality of the population in the area. Aim of this study is to explore the relationship between the exposure to landslides occurrence by considering the landslide susceptibility map, that is the potential for an area to become unstable and the population dynamics in Molise, with a particular focus on population dynamics and its relation with susceptibility and exposure. For each municipality of the region we attempt to find a correspondence between the areal extension of the elements exposed to landslide susceptibility, and the Demographic Malaise State indicator (SMD). The SMD is a composite index that analyses the changes of growing/decreasing rates in the local population. This can lead to a better understanding of how the environment degradation (in terms of landslide occurrence and evolution) could promote out-migration from the affected areas. The observed results indicate that for the case study there is indeed a certain connection between the landslide exposure of the analyzed assets and the SMD, especially in the central area of the region, where the susceptibility is higher. This study is a contribution to improve the knowledge of the relationships among landslide prone areas and social effects in the Molise territory, which can be essential for the development of efficient strategies for landslide risk reduction.

Multi-Temporal Landslide Susceptibility Maps and Future Scenarios for Expected Land Cover Changes (Southern Apennines, Italy)

Human activities, including extensive land use practices, such as deforestation and intensive cultivation, may severely affect the landscape, and have caused important changes to the extent of natural forests during the last century in Southern Italy. Such changes had a strong influence on the frequency of occurrence of natural hazards, including landslides. Being one of the most significant control factors of slope movements, any variation in land cover pattern may determine changes in landslide distribution. The study area is the Rivo Basin which is located in Molise (Southern Apennines of Italy), a region severely affected by landslides. We prepared multi-temporal land cover and landslide inventory maps, aimed at developing different susceptibility maps to evaluate the effects of land cover changes in the predisposition to landslides. Based on the observed land cover trends in the study area, we simulated future scenarios of land cover in the attempt to assess potential future changes in landslide distribution and susceptibility. By investigating the relationship between the spatial pattern and distribution of past land cover settings and location factors (as elevation, slope, distance to settlements), we were able to calibrate a land cover change model to simulate future scenarios. The obtained results give important information both regarding the impact of past trends of land cover changes on landslide occurrence and possible future directions. They could be useful to provide insights toward a better land management for the study area, as well as for similar landslide-prone environments in Southern Italy, contributing to establish good practices for future landslide risk mitigation.

Landslide susceptibility zonation at the regional scale: the Molise case study (Italy)

Molise is an Italian region with a high concentration of landslides. However, an estimation of landslide susceptibility for the entire region has never been officially performed. In this paper, a landslide susceptibility analysis is illustrated based on the implementation of two different statistical methods (bivariate and multivariate). The aim is to obtain a susceptibility map that provides a good representation of the criticality of the study area together with a reliable statistical performance. Various combinations of conditioning factors were tested with the two methods and, based on expert judgment and ROC (Receiver Operating Curve) values, the one obtained through the multivariate approach was selected as the best map.