Land degradation versus fire: A spiral process?

Abstract

Originally associated to arid regions, vulnerability to land degradation (LD) has rapidly spread in temperate areas, such as the Mediterranean basin. In this region LD increased in the last years due to worsening climate conditions, land-cover changes, soil erosion and anthropogenic pressures. Increasing land vulnerability is mutually linked with an increasing risk of disturbance propagation: the spatio-temporal distribution of areas with different degrees of LD determines different dynamic patterns of the disturbance; in turn, LD is strongly affected by the disturbance occurrence regime, which alters the status quality of a given territory. These considerations invite a comparison between vulnerability to LD and fire occurrence, since historically, in the Mediterranean areas, fire represents one of the main disturbance sources, which is mostly human-induced and with a strong seasonality pattern. Under certain conditions, LD may create conducive conditions for fire to thrive that in turn if repeated may alter the quality status of a landscape, setting the interested area into a LD-fire feedback dynamic. The aim of this paper is to analyse the relationship between fire incidence and LD and their potential feedbacks in Sardinia during two reference periods, 1990 and 2000. Results indicated that in areas already affected by high LD vulnerability there is a sort of LD-fire spiralling connection that can be seen as a 'mutual early-warning system' with strong implications on fire prevention strategies and landscape quality status monitoring

Desperately Seeking Sustainability: Urban Shrinkage, Land Consumption and Regional Planning in a Mediterranean Metropolitan Area

“…Conserving relict natural ecosystems is a key issue in the sustainable land management of suburban areas [33]. Our results suggest that planning strategies against land degradation have to distinguish passive degradation deriving from the past environmental dynamics-and often requiring land restoration-from active degradation, needing permanent assessment and specific policy response [28].…”

“…The outcomes of the ESA model have been extensively validated on the ground [10,23,33]. A specific assessment [24] based on heterogeneous datasets with different reliability, confirms that the ESA indicators are reliable proxies for land quality and vulnerability to degradation in the Mediterranean region [28].…”

“…The ESA procedure allowed to rank each spatial unit according to a score based on the estimated degree of correlation with LD processes [24]. The weighting system introduced by Bajocco et al [33] was adopted to the specificity of the local context and supplemented with information taken from Salvati et al [10,28], Lavado Contador et al [24] and Ferrara et al [25]. Despite its acknowledged importance as a tool to detect vulnerability of land to degradation, the ESA approach presents some shortcomings: the assessment of the importance of the individual variables or thematic indicators is quite simple [25] and the input variables are oriented towards the in-depth description of biophysical conditions of the area, leaving out some important socio-political and cultural factors [10].…”

“…Despite its acknowledged importance as a tool to detect vulnerability of land to degradation, the ESA approach presents some shortcomings: the assessment of the importance of the individual variables or thematic indicators is quite simple [25] and the input variables are oriented towards the in-depth description of biophysical conditions of the area, leaving out some important socio-political and cultural factors [10]. Small changes in the input variables from the original formulation of the ESAI introduced by Basso et al [23] were proposed to overcome the drawbacks mentioned above and to address place-specific factors [10,28,33]. Lavado Contador et al [24] and Ferrara et al [25] demonstrated that the ESA algorithm is rather stable over changes in the input variables.…”

“…The ESA model evaluates land quality by assessing place-specific conditions predisposing land to potential degradation [33]. Land vulnerability results from a combination of inadequate land management together with a particular set of environmental factors, including soil, climate and vegetation [24].…”