Probabilistic modelling of wildfire occurrence based on logistic regression, Niassa Reserve, Mozambique

Eufrásio João Sozinho Nhongo,Denise Cybis Fontana,Laurindo Antonio Guasselli,Carolina Bremm

doi:10.1080/19475705.2019.1615559

Abstract

Fires are one of the main factors for disturbances in Niassa Reserve-Mozambique, with economic and environmental impacts. There are cyclical records of fire occurrences across the reserve. However, studies on the main causative factors and identification of more susceptible locations are very limited. In this perspective, this study had as objectives: (1) determine the main significant factors for wildfire occurrences; (2) Map the probability of wildfire occurrences, using logistic regression. Independent variables included vegetation index (NDVI), climatic, topographic and socioeconomic data. The analysis period was from 2001 to 2015 and comprised the months with more occurrences of wildfire (May to December). According to the results, the main factors that determine the occurrence of fires were: NDVI, temperature, elevation, followed by precipitation, slope, relative humidity and human settlements. The spatial distribution of probability of fire occurrence reveals that zones with high and very high risk are located at the west and central west zones (areas with higher accumulation of dry biomass); medium risk zones are located in the centre of the reserve, while in central east and east zones the probability of fire occurrence is low and very low risk. Results showed that the expectation of wildfire ignition using logistic regression presented good precision (area under the curve 74%).

Highlights

Wildfire is one of the most important sources of economic, social and environmental damages globally (Lozano et al 2008; Renard et al 2012)
Modelling approach To estimate the probability of fire risk in Niassa Reserve, logistic regression was applied based on the following equation: Pi
A preliminary analysis of fire spatial distribution against the variables selected (Figure 2) shows that the highest frequencies of fires occurred in areas where temperatures were mild, with low precipitation (

Summary

Introduction

Wildfire is one of the most important sources of economic, social and environmental damages globally (Lozano et al 2008; Renard et al 2012). Niassa Reserve is the most extensive area of miombo vegetation conservation worldwide (Ribeiro et al 2008), with one of the largest fauna concentrations in Mozambique (Leo-Smith et al 2007). From 2000 to 2012 alone, 45% of the reserve area burnt annually or over two years, and 27% burnt each 3–4 years, only 9% of the total area did not record burning during this period (Ribeiro et al 2017). According to this same author, fire in the Reserve presents a return interval of 3.29 years, which means a total frequency of 0.36 year–1

Methods

Results

Discussion

Conclusion