INTEGRATION OF AN MCA-GIS APPROACH FOR THE MODELLING AND ASSESSMENT OF MASS MOVEMENT RISK. CASE OF AЇN EL HAMMAM, BASIN OF TIZI-OUZOU (ALGERIA)

This paper presents a three-step approach to evaluate and map mass movement risk. First, hazard and vulnerability, the two components of mass movement risk, are evaluated through the use of a Weighted Product Method (WPM) borrowed to the Multi-Attribute Utility Theory (MAUT). The model evaluates each potential action a A (set of potential actions) according to a set of attributes, points of view and criteria i, i = 1, ..., n, from gi measurement scales. The criteria retained are environmental factors of susceptibility to landslides and surrounding elements at risk (stakes). In a second phase, the risk is estimated by the product of its two components. Finally, the spatial mass movement risk is determined by crossing the susceptibility (hazard) and consequences (vulnerability) maps. The method has been tested in the area of Aїn el Hammam in the basin of Tizi-Ouzou (Algerian Tell)

Wildfire risk for main vegetation units in a biodiversity hotspot : modeling approach in New Caledonia, South Pacific

Wildfire has been recognized as one of the most ubiquitous disturbance agents to impact on natural environments. In this study, our main objective was to propose a modeling approach to investigate the potential impact of wildfire on biodiversity. The method is illustrated with an application example in New Caledonia where conservation and sustainable biodiversity management represent an important challenge. Firstly, a biodiversity loss index, including the diversity and the vulnerability indexes, was calculated for every vegetation unit in New Caledonia and mapped according to its distribution over the New Caledonian mainland. Then, based on spatially explicit fire behavior simulations (using the FLAMMAP software) and fire ignition probabilities, two original fire risk assessment approaches were proposed: a one-off event model and a multi-event burn probability model. The spatial distribution of fire risk across New Caledonia was similar for both indices with very small localized spots having high risk. The patterns relating to highest risk are all located around the remaining sclerophyll forest fragments and are representing 0.012% of the mainland surface. A small part of maquis and areas adjacent to dense humid forest on ultramafic substrates should also be monitored. Vegetation interfaces between secondary and primary units displayed high risk and should represent priority zones for fire effects mitigation. Low fire ignition probability in anthropogenic-free areas decreases drastically the risk. A one-off event associated risk allowed localizing of the most likely ignition areas with potential for extensive damage. Emergency actions could aim limiting specific fire spread known to have high impact or consist of on targeting high risk areas to limit one-off fire ignitions. Spatially explicit information on burning probability is necessary for setting strategic fire and fuel management planning. Both risk indices provide clues to preserve New Caledonia hot spot of biodiversity facing wildfires

Wildfire hazard and Risk modelling in the Northern regions of Ghana using GIS-based Multi-Criteria Decision Making Analysis

There has been tremendous adverse impact of fire outbreaks across the world over the last two decades. The human cost has been devastating and economic losses have exceeded an annual average of US$2500 million. Regardless of its importance in plant community regeneration, wildfires have been tremendously devastative to human societies and Earth’s ecosystems. To adequately manage wildfires and reduce their adverse effects, estimating the probability of occurrence of wildfires and critically assessing the spatially variable environmental conditions that affect the propagation and impact of these fires is imperative. This study integrates the broader biophysical and environmental variables with anthropogenic factors to model and predict spatial variation in hazard, vulnerability and risk of wildfires in the Savannah, Northeast and Northern regions of Ghana. These areas are characterised by endemic poverty and agrarian activity, which is the major source of livelihood for about 71% of the population. Disasters such as wildfires are therefore detrimental, severely undermining the natural capital relied on for livelihoods and further aggravating the high poverty rates in these regions. Against this backdrop, a GIS-based Multi Criteria Decision Making Analysis method (GIS-MCDA) – the Analytical Hierarchy Process (AHP) was used to map wildfire hazard and risk within these regions to aid response and mitigation. A wildfire risk map was then produced by developing and integrating hazard and vulnerability models. Results indicate that about 71.7% (48035 ) of the study area is highly exposed to wildfire hazard and about 13% of the study region is likely to experience the greatest risk when wildfires occur, although this is concentrated around urban settlements. It is recommended that future studies integrate intersectional social and economic characteristics to provide a more robust definition of vulnerable and at-risk communities and cultural infrastructure. Keywords: Wildfires, Vulnerability, Risk, GIS multi-criteria decision making, Northern Ghana DOI: 10.7176/JEES/10-11-02 Publication date: November 30th 202