No evidence of increased fire risk due to agricultural land abandonment in Sardinia (Italy)

C. Ricotta,A. Migliozzi,D. Guglietta

doi:10.5194/nhess-12-1333-2012

Abstract

Abstract. Different land cover types are related to different levels of fire hazard through their vegetation structure and fuel load composition. Therefore, understanding the relationships between landscape changes and fire behavior is of crucial importance for developing adequate fire fighting and fire prevention strategies for a changing world. In the last decades the abandonment of agricultural lands and pastoral activities has been the major driver of landscape transformations in Mediterranean Europe. As agricultural land abandonment typically promotes an increase in plant biomass (fuel load), a number of authors argue that vegetation succession in abandoned fields and pastures is expected to increase fire hazard. In this short paper, based on 28 493 fires in Sardinia (Italy) in the period 2001–2010, we show that there is no evidence of increased probability of fire ignition in abandoned rural areas. To the contrary, in Sardinia the decreased human impact associated with agricultural land abandonment leads to a statistically significant decrease of fire ignition probability.

Highlights

Wildland fires affect large areas and cause serious damage, having ecological, social and economic consequences
In the Mediterranean Basin, where most fires are of human origin, fire behavior is affected to some extent by the different land use and land cover (LULC) types (Nunes et al, 2005; Bajocco and Ricotta, 2008; Catry et al, 2009)
Different LULC types are subject to different levels of human pressure and to different levels of ignition risk related to anthropogenic fires of intentional or accidental origin (Bajocco et al, 2011)

Summary

Introduction

Wildland fires affect large areas and cause serious damage, having ecological, social and economic consequences. While fire risk embodies a clear and simple probabilistic/frequentistic concept (i.e. the chance that a fire might start, independently of how large the fire will be), fire hazard is a more complex concept that is related to the potential fire behavior for a fuel type, including the probability that an ignition will result in a large burned area In this sense, as fire hazard is, by definition, tightly connected to biomass availability, the observation that the rural exodus increases fire hazard due to the increased fuel load in the abandoned areas is not really surprising, adding little to our knowledge on the influence of landscape change on fire behavior. In this short paper, focusing on fire risk rather than on fire hazard, we argue that there is no evidence of increased probability of fires starting in Sardinia (Italy) in the period 2001–2010 due to agricultural land abandonment

Study area

Materials and methods

Results and discussion