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

Abstract

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.

Old Lineage on an Old Island: Pixibinthus, a New Cricket Genus Endemic to New Caledonia Shed Light on Gryllid Diversification in a Hotspot of Biodiversity

“…This increasing change in fire regime created a large vegetation mosaic of maquis-forest, dominated by flammable maquis, especially in the southern part of New Caledonia. This mosaic influence fire regime with more maquis prone to burn rather than forest remnants [ 93 , 95 ]. Before man arrival, the low regime of fire was related to a maquis-forest mosaic dominated by forest, which we hypothesize offer more opportunity of stable open shrubby maquis areas available for Pixibinthus population with a low turn over (a mosaic of maquis minier of differents ages in a matrix of forest).…”

Impact of Austropuccinia psidii in New Caledonia, a biodiversity hotspot

“…New Caledonia is a French archipelago located in the south‐west Pacific. It comprises a main island, called “Grande Terre,” and small islands, including the “Loyauté Islands.” New Caledonia is renowned for its extraordinary botanical richness, which is ranked third in terms of world endemism (Gomez et al., ; Morat, ). The flora of New Caledonia includes approximately 257 species of Myrtaceae, of which 99% are endemic, which makes Myrtaceae the most species‐rich angiosperm family in this territory (Grandcolas et al., ; Kier et al., ; Morat et al., ; Myers, Mittermeier, Mittermeier, da Fonseca, & Kent, ).…”

Assessing Climate Change Impacts on Wildfire Exposure in Mediterranean Areas

“…Landscape fire spread and behavior models such as FSim, FlamMap, and its command line version Randig allow simulating thousands of fires and generating burn probability and intensity maps based on the minimum travel time (MTT) algorithm . The models have been tested and applied in a number of fire systems in the United States, Canada, Portugal, and the Mediterranean basin . However, these models have not been fully leveraged…”