A multi-component flood risk assessment in the Maresme coast (NW Mediterranean)

Coastal regions are the areas most threatened by natural hazards, with floods being the most frequent and significant threat in terms of their induced impacts, and therefore, any management scheme requires their evaluation. In coastal areas, flooding is a hazard associated with various processes acting at different scales: coastal storms, flash floods, and sea level rise (SLR). In order to address the problem as a whole, this study presents a methodology to undertake a preliminary integrated risk assessment that determines the magnitude of the different flood processes (flash flood, marine storm, SLR) and their associated consequences, taking into account their temporal and spatial scales. The risk is quantified using specific indicators to assess the magnitude of the hazard (for each component) and the consequences in a common scale. This allows for a robust comparison of the spatial risk distribution along the coast in order to identify both the areas at greatest risk and the risk components that have the greatest impact. This methodology is applied on the Maresme coast (NW Mediterranean, Spain), which can be considered representative of developed areas of the Spanish Mediterranean coast. The results obtained characterise this coastline as an area of relatively low overall risk, although some hot spots have been identified with high-risk values, with flash flooding being the principal risk process

Mediterranean shrublands as carbon sinks for climate change mitigation: new root-to-shoot ratios

Shrublands play an important role in the reduction of atmospheric CO2 and contribute to the mitigation of the effects of climate change, due to their ability to act as carbon sinks and the large expanses of land involved. Two of the most representative shrub species in the Iberian Peninsula, Cistus ladanifer L. and Erica arborea L., were studied in terms of biomass distribution and carbon and nitrogen contents in the different fractions. With a view to fast and cost-effective estimation of radical biomass, a new procedure for easy root-to-shoot calculation based on vibrational data was proposed, resulting in an excellent agreement with the values obtained from conventional direct belowground and aerial biomass measurements: 0.23 for C. ladanifer and 0.54 for E. arborea. Carbon sequestration, estimated at 45 and 73 t CO2 eq·ha-1 for C. ladanifer and E. arborea, respectively, was subsequently determined. Since these values are substantially higher than those of other shrubs, these two key species can be deemed particularly promising for ecological restoration and carbon offsetting

Scattered or polycentric? Untangling urban growth in three southern European metropolitan regions through exploratory spatial data analysis

The present study illustrates an exploratory spatial data analysis (ESDA) aimed at investigating changes in the distribution of built-up areas in three southern European metropolitan regions (Barcelona, Rome and Athens). An approach based on global Moran's indexes of spatial autocorrelations was proposed to assess similarities in the spatial organization of the three regions, based on land-use data for 1960 and 2010. Compact monocentric, scattered low-density and mixed polycentric structures were compared in the three regions using local Moran's indexes computed at two different scales, "urban" (5 km radius) and "regional" (20 km radius). The proposed approach identifies emerging trends in scattered monocentric or polycentric development. Our results outline the trend toward scattered urban expansion for the three cities, with signs of a modest shift toward polycentrism in Barcelona. ESDA provides basic information needed for policies promoting spatially balanced, sustainable development in originally compact and economically segmented regions