Francisco Moreira
email: fmoreira@isa.utl.pt

Olga Viedma
email: olga.viedma@uclm.es

Margarita Arianoutsou

Thomas Curt
email: thomas.curt@cemagref.fr

Nikos Koutsias
email: nkoutsia@cc.uoi.gr

Eric Rigolot
email: eric.rigolot@avignon.inra.fr

Anna Barbati

Piermaria Corona
email: piermaria.corona@unitus.it

Pedro Vaz

Gavriil Xanthopoulos

Florent Mouillot
email: florent.mouillot@cefe.cnrs.fr

Ertugrul Bilgili
email: ertbilgili@ktu.edu

Landscape -wildfire interactions in Southern Europe: implications for landscape management

Keywords: Fire hazard, landscape changes, land use/land cover changes, land management, Mediterranean, fire regime, climate change

Every year approx. half a million hectares of land are burned by wildfires in southern Europe, causing large ecological and socio-economic impacts. Climate and land use changes in the last decades have increased fire risk and danger. In this paper we review the available scientific knowledge on the relationships between landscape and wildfires in the Mediterranean region, with a focus on its application for defining landscape management guidelines and policies that could be adopted in order to promote landscapes with lower fire hazard. The main findings are that (1) socio-economic drivers have favoured land cover changes contributing to increasing fire hazard in the last decades, (2) large wildfires are becoming more frequent, (3) increased fire frequency is promoting homogeneous landscapes covered by fire-prone shrublands; (4) landscape planning to reduce fuel loads may be successful only if fire weather conditions are not extreme. The challenges to address these problems and the policy and landscape management responses that should be adopted are discussed, along with the major knowledge gaps.

Introduction

Every year about 45000 forest fires occur in southern Europe, burning approximately 0.5 million hectares of forests and other rural lands [START_REF] Camia | Forest Fires in Europe[END_REF]. Despite the resources invested in fire prevention and suppression, the number of fires in recent decades has continued to increase remarkably (JRC, 2005). There is growing concern about the ecological and socio-economic impacts of wildfires, particularly under a climate change context that implies an increase in the frequency and severity of wildfires in European countries in the future (e.g. [START_REF] Arianoutsou | Resilience of Mediterranean vegetation to fire: issues under the global change scenarios[END_REF][START_REF] Mouillot | Simulating climate change impacts on fire frequency and vegetation dynamics in a Mediterranean-type ecosystem[END_REF][START_REF] Pausas | Changes in fire and climate in the Eastern Iberian Peninsula (Mediterranean Basin)[END_REF][START_REF] Piñol | Climate warming and wildfire hazard and wildfire occurrence in coastal eastern Spain[END_REF].

At landscape level, ignition and spread of wildfires result from a complex interaction among ignition sources, weather, topography and land cover (e.g. [START_REF] Mermoz | Landscape influences on occurrence and spread of wildfires in Patagonian forests and shrublands[END_REF][START_REF] Rothermel | How to predict the spread and intensity of forest and range fires[END_REF]. From a management perspective, land cover (related to vegetation structure and fuel loads) is the only landscape variable influencing fire behaviour that can be manipulated. Wildfires start from a local epicentre (ignition point) and spread across landscapes as a function of the abundance and arrangement of disturbance-susceptible patches [START_REF] Forman | Land Mosaics. The Ecology of Landscapes and Regions[END_REF][START_REF] Turner | Predicting the spread of disturbance across a heterogeneous landscape[END_REF]. Fire spread rate can be facilitated or retarded by landscape heterogeneity [START_REF] Turner | Modeling landscape disturbance[END_REF]. Thus, the spatial pattern of fire ignition and spread across landscapes are affected by fire proneness, i.e. the differential fire behaviour in various land cover types that are not equally fire-prone (e.g. [START_REF] Bajocco | Evidence of selective burning in. Sardinia (Italy): Which land-cover classes do wildfires prefer?[END_REF][START_REF] Moreira | Regional variations in wildfire susceptibility of land-cover types in Portugal: implications for landscape management to minimize fire hazard[END_REF]Moreno et al., in press).

Understanding this link between landscape pattern and fire spread would facilitate the definition of landscape-level management rules so that Mediterranean landscapes become less fire-prone. A straightforward application of this knowledge lies in the definition of landscape-scale fuel breaks, whose main objective is to reduce fuel loads or change the spatial arrangement of fuels (i.e. the landscape structure), so that when a wildfire ignites in a well managed landscape, it spreads more slowly, burns with less intensity and severity, and is less costly to suppress (e.g. [START_REF] Duguy | Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)[END_REF]. However, the management implications of understanding the landscape-fire relationships are not restricted to fuel break design, but they also enable the definition of land use management rules and the design and implementation of policies leading to specific landscape goals (in terms of overall fuel patterns), ranging from forest and agricultural and rural development, to urban development policies.

In this paper, we review the available scientific literature on the relationships between fires and landscape patterns and provide a critical evaluation of the scientific findings with relevant implications for landscape management. We concentrate on the geographic region covered by European Mediterranean countries where fire hazard is highest and scientific research still has important knowledge gaps. We have organised the structure of this review as a series of sections, each starting with a sentence that constitutes a key message for landscape and policy managers, and then reviewing and summarising the available scientific support. The basic structure of the approach used is shown in Figure 1. The concluding section addresses overall recommendations for landscape managers, knowledge gaps, and future trends under climate change.

# Figure 1 approximately here

Key concepts

Across the text we will use the definitions of [START_REF] Hardy | Wildland fire hazard and risk: Problems, definitions, and context[END_REF] for fire risk (the chance that a fire might start) and fire hazard (a fuel complex, defined by volume, type, condition, arrangement, and location that determines the degree of ease of ignition and the resistance to control). Fire hazard expresses the potential fire behaviour for a fuel type, regardless of the fuel type's weather-influenced fuel moisture content [START_REF] Hardy | Wildland fire hazard and risk: Problems, definitions, and context[END_REF]. Fire danger is commonly defined by the factors affecting the ignition, propagation, difficulty of control, and fire effects on the ecosystem [START_REF] Helms | The Dictionary of Forestry[END_REF]. Fire weather is defined as the weather conditions which influence fire ignition, behavior and suppression.What is a large fire (LF), in terms of burned area, depends on the region on the globe [START_REF] Viegas | Weather, fuel status and fire occurrence: predicting large fires[END_REF] and it can be defined as the upper tail of the fire size frequency distributions [START_REF] Gill | Large fires, fire effects and the fire regime concept[END_REF]. In Europe, fires above 100 ha (e. g. [START_REF] Bermudez | Spatial and temporal extremes of wildfire sizes in Portugal[END_REF], 500 ha [START_REF] Moreno | Recent history of forest fires in Spain[END_REF] or 1000 ha [START_REF] Piñol | Climate warming and wildfire hazard and wildfire occurrence in coastal eastern Spain[END_REF][START_REF] Viegas | Weather, fuel status and fire occurrence: predicting large fires[END_REF] are generally considered as LF. Along the paper we also use the terms fire intensity and fire severity according to [START_REF] Keeley | Fire intensity, fire severity and burn severity: a brief review and suggested usage[END_REF]. Thus, fire intensity refers to the energy release during a fire, expressed as, e.g. temperature or fireline intensity. Fire severity relates to the loss or decomposition of organic matter above or below ground. It is, thus, a measure of the impact of the fire on soil and vegetation. Typical indicators of fire severity include plant mortality, the degree of tree canopy damage by a fire, or the amount of surface litter consumed.

Mediterranean landscapes have increased fire hazard in the last decades: the role of land use / land cover.

Land use / land cover (LULC) changes are related to fire hazard through changes in vegetation structure and fuel load composition which, along with topography and weather, are the main drivers of fire intensity and rate of spread [START_REF] Fernandes | Combining forest structure data and fuel modelling to classify fire hazard in Portugal[END_REF][START_REF] Fernandes | A review of prescribed burning effectiveness in fire hazard reduction[END_REF][START_REF] Moreira | Regional variations in wildfire susceptibility of land-cover types in Portugal: implications for landscape management to minimize fire hazard[END_REF][START_REF] Rothermel | How to predict the spread and intensity of forest and range fires[END_REF]. Thus, changes in LULC are directly linked to changes in landscape fuel patterns and fire hazard [START_REF] Moreira | Regional variations in wildfire susceptibility of land-cover types in Portugal: implications for landscape management to minimize fire hazard[END_REF]Moreno et al., in press). Increased fire hazard is expected where LULC changes have promoted an increase in plant biomass (fuel load), such as those resulting from the abandonment of agricultural lands (e.g. vegetation succession in abandoned farms, pastures or woodlands) or from afforestation activities (Table 1). Conversely, other LULC changes will decrease fire hazard when associated with the removal of biomass (e.g. land clearing or forest harvesting) [START_REF] Rego | Land use changes and wildfires[END_REF].

Land cover influences fire patterns

Studies of fire patterns in landscapes confirm the differences in fire hazard associated with different LULC. Several studies have demonstrated that shrublands are the land cover most prone to fire, i.e. with a higher burned proportion than expected from the availability of this land cover in the landscape, in different places of the Mediterranean basin: Spain [START_REF] Diaz-Delgado | Spatial patterns of fire occurrence in Catalonia, NE, Spain[END_REF][START_REF] Gonzalez | A fire probability model for forest stands in Catalonia (north-east Spain)[END_REF][START_REF] Gonzalez | Characterization of forest fires in Catalonia (northeast Spain)[END_REF][START_REF] Lloret | Wildfires and landscape patterns in the Eastern Iberian Peninsula[END_REF][START_REF] Sebastian-Lopez | Integration of socio-economic and environmental variables for modelling longterm fire danger in Southern Europe[END_REF], France [START_REF] Mouillot | Some determinants of the spatio-temporal fire cycle in a Mediterranean landscape (Corsica, France)[END_REF][START_REF] Mouillot | Long-term forest dynamic after land abandonment in a fire prone Mediterranean landscape (central Corsica, France)[END_REF], Portugal [START_REF] Moreira | Temporal (1958-1995) pattern of change in a cultural landscape of northwestern Portugal: implications for fire occurrence[END_REF][START_REF] Moreira | Regional variations in wildfire susceptibility of land-cover types in Portugal: implications for landscape management to minimize fire hazard[END_REF][START_REF] Nunes | Land cover type and fire in Portugal: do fires burn land cover selectively?[END_REF], Italy [START_REF] Bajocco | Evidence of selective burning in. Sardinia (Italy): Which land-cover classes do wildfires prefer?[END_REF], and Greece [START_REF] Koutsias | Is there any special pattern of the extreme wildland fires occurred in Greece in the summer of 2007?[END_REF]). This can be explained by several factors, namely the lower priority given for fire fighting in shrublands (on the assumption that they are the least valuable land cover), the number of human-caused ignitions (e.g. burning for rangeland management purposes, such as creating pastures) and the higher rate of fire spread in this LULC [START_REF] Duguy | Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)[END_REF][START_REF] Fernandes | Combining forest structure data and fuel modelling to classify fire hazard in Portugal[END_REF][START_REF] Moreira | Regional variations in wildfire susceptibility of land-cover types in Portugal: implications for landscape management to minimize fire hazard[END_REF]. Additionally, as a consequence of shallower soils that prevent dense forest to establish (Garcia-Fayos et al., 1998) and abandonment of hard to mechanize terrace cultivation [START_REF] Tatoni | Secondary succession on abandonned cultivation terraces in calcareous Provence. I -Vegetation and soil[END_REF], shrublands are a common land cover type in steeper slopes where the rate of fire spread is higher. On the contrary, cultivated areas (particularly those with irrigated crops) are the LULC less fire prone, burning in a lower proportion than the surface they cover in the landscape [START_REF] Nunes | Land cover type and fire in Portugal: do fires burn land cover selectively?[END_REF][START_REF] Moreira | Regional variations in wildfire susceptibility of land-cover types in Portugal: implications for landscape management to minimize fire hazard[END_REF]Moreno et al., in press). The main reasons for the low fireproneness of agricultural areas include their low combustibility, and their geographic association with human presence enabling quicker fire detection and easier fire fighting. Forests are usually more fire prone than agricultural areas, but less susceptible than shrublands. Within a forest context, studies in Portugal suggest that mature forests of broadleaved deciduous and mixed forests generally have a low fire hazard compared to pure pine forests, eucalypt plantations, or mixed pine and eucalyptus stands [START_REF] Fernandes | Combining forest structure data and fuel modelling to classify fire hazard in Portugal[END_REF][START_REF] Moreira | Regional variations in wildfire susceptibility of land-cover types in Portugal: implications for landscape management to minimize fire hazard[END_REF]. However, forest structure may be more important than forest composition in defining hazard [START_REF] Fernandes | Combining forest structure data and fuel modelling to classify fire hazard in Portugal[END_REF]. In fact, differences between forest types may be explained by different fuel structures, e.g. the degree of canopy closure that limits the development of a grassy or shrubby fuel bed and maintains vegetation with high moisture content [START_REF] Gracia | Mid-term successional patterns after fire of mixed pine-oak forests in NE Spain[END_REF][START_REF] Pausas | Are wildfires a disaster in the Mediterranean basin? -A review[END_REF][START_REF] Vazquez | Recent fire regime characteristics and potential natural vegetation relationships in Spain[END_REF][START_REF] Zavala | Constraints and trade-offs in Mediterranean plant communities: the case of holm oak-Aleppo pine forests[END_REF]. There is some evidence that mature evergreen oak forests can even become 'self-protective' against wildfire, to the point of fire selfextinction [START_REF] Fernandes | Changes in wildfire severity from maritime pine woodland to contiguous forest types in the mountains of northwestern Portugal[END_REF].

In addition to landscape composition, landscape configuration also has strong implications for fire hazard. For example, the spatial patterns formed after the abandonment of rural areas have created landscapes of high combustibility through increasing significantly the availability and contiguity of fuel loads (e.g. [START_REF] Mazzoleni | Recent Dynamics of the Mediterranean Vegetation and Landscape[END_REF][START_REF] Sluiter | Spatial patterns of Mediterranean land abandonment and related land cover transitions[END_REF][START_REF] Saglam | Spatiotemporal analysis of forest fire risk and danger using LANDSAT imagery[END_REF]. Some studies have confirmed that fire hazard was greater in the more contiguous and homogeneous landscape portions [START_REF] Lloret | Wildfires and landscape patterns in the Eastern Iberian Peninsula[END_REF]Vega-Garcia and Chuvieco, 2006). Other studies applied fire resistance rules to LULC types at the scale of fire events [START_REF] Viedma | Landscape structural features control fire size in a Mediterranean forested area of central Spain[END_REF] or at both stand and landscape scales [START_REF] Gonzalez | Integrating fire risk considerations in forest management planning in Spain -a landscape level perspective[END_REF][START_REF] Gonzalez | Assessing functional landscape connectivity for disturbance propagation on regional scales -A cost-surface model approach applied to surface fire spread[END_REF] and showed that landscape resistance to fire was negatively influenced by the spatial contiguity of LULC, and positively influenced by the diversity resulting from fuel contrast at fire edges. Simulation models also showed that fire spread and behaviour were greatly influenced by fuel spatial distribution [START_REF] Duguy | Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)[END_REF].

Landscape changes have been increasing fire hazard in the last decades

Studies of LULC changes in the Mediterranean Europe typically have a time span of 30 to 50 years, since the 1950's (coinciding with the first available aerial photographs) to the beginning of the XXI century, although there are exceptions, e.g. [START_REF] Preiss | Rural depopulation and recent landscape changes in a Mediterranean region: consequences to the breeding avifauna[END_REF]ca. 15 years) and [START_REF] Mouillot | Long-term forest dynamic after land abandonment in a fire prone Mediterranean landscape (central Corsica, France)[END_REF]more than 200 years). The usual extension of a study area is 3000-5000 ha, but is also highly variable, e.g. 40 ha in [START_REF] Baudry | Changes in landscape patterns and vegetation dynamics in Provence, France[END_REF] to the whole of Italy [START_REF] Falcucci | Changes in land-use/land-cover patterns in Italy and their implications for biodiversity conservation[END_REF]. Aerial photographs, satellite images and land use or land cover maps have been the most common sources of data used.

A large number of studies has provided evidence of increased fire hazard in Meditarreanean rural areas, mainly due to the increased cover of forests and shrublands in areas with former lower fuel loads and fire hazard (e.g. agricultural or pastoral land) (Table 1). For example, Van Doorn and Baker (2007), in a region of southern Portugal, registered a 75% decline in the area of agricultural fields during the period 1985-2000, and an increase in matorral (shrubland) and forest plantations. [START_REF] Falcucci | Changes in land-use/land-cover patterns in Italy and their implications for biodiversity conservation[END_REF], for the whole of Italy, measured a 74% increase in forest cover during the period 1960-2000, and a 20% decrease in agricultural areas.

# Table 1 approximately here

Several other studies have shown similar patterns of change across different countries: Portugal [START_REF] Moreira | Temporal (1958-1995) pattern of change in a cultural landscape of northwestern Portugal: implications for fire occurrence[END_REF][START_REF] Moreira | Modelling the impact of agricultural abandonment and wildfires on vertebrate diversity in Mediterranean Europe[END_REF], Spain [START_REF] Lloret | Wildfires and landscape patterns in the Eastern Iberian Peninsula[END_REF][START_REF] Pérez | Effects of the recent land-use history on the postfire vegetation of uplands in Central Spain[END_REF][START_REF] Romero-Calcerrada | The role of land abandonment in landscape dynamics in the SPA 'Encinares del rio Alberche y Cofio, Central Spain, 1984-1999[END_REF][START_REF] Viedma | Interactions between land use/land cover change, forest fires and landscape structure in Sierra de Gredos (Central Spain)[END_REF]Vega-Garcia and Chuvieco, 2006;[START_REF] Duguy | Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)[END_REF][START_REF] Hill | Mediterranean desertification and land degradation: Mapping related land use change syndromes based on satellite observations[END_REF][START_REF] Olarieta | Preserving and destroying soils, transforming landscapes: Soils and land-use changes in the Vallès County (Catalunya, Spain) 1853-2004[END_REF], France [START_REF] Debussche | Mediterranean landscape changes: evidence from old postcards[END_REF][START_REF] Taillefumier | Contemporary land use changes in prealpine Mediterranean mountains: a multivariate GIS-based approach applied to two municipalities in the Southern French Prealps[END_REF][START_REF] Mouillot | Long-term forest dynamic after land abandonment in a fire prone Mediterranean landscape (central Corsica, France)[END_REF], Italy [START_REF] Peroni | Temporal and spatial changes in a mountainous area of central Italy[END_REF], Greece [START_REF] Papanastasis | Landuse changes and landscape dynamics in Western Crete[END_REF]) and Israel [START_REF] Carmel | Effects of grazing and topography on long-term vegetation changes in a Mediterranean ecosystem in Israel[END_REF], among others.

Agricultural land abandonment, including the decline of pastoral activities, is the major driver of landscape changes and increased fire hazard (Table 1), mainly in mountainous areas [START_REF] Acosta | Landscape change and ecosystem classification in a municipal district of a small city (Isernia, Central Italy)[END_REF]Aranbazal et al. 2008;[START_REF] Falcucci | Changes in land-use/land-cover patterns in Italy and their implications for biodiversity conservation[END_REF][START_REF] Macdonald | Agricultural abandonment in mountain areas of Europe[END_REF][START_REF] Papanastasis | Landuse changes and landscape dynamics in Western Crete[END_REF]. This abandonment is caused by the low economic profitability of these areas and is often associated with ageing, emigration and rural population declines. Marginal agricultural land, often located in steeper slopes, is the first to be abandoned (e.g. [START_REF] Peroni | Temporal and spatial changes in a mountainous area of central Italy[END_REF][START_REF] Sluiter | Spatial patterns of Mediterranean land abandonment and related land cover transitions[END_REF]Van Doorn and Baker, 2007). Vegetation succession then leads to scrub encroachment and forest development (e.g. [START_REF] Arianoutsou | Landscape changes in Mediterranean Ecosystems of Greece: implications for Fire and Biodiversity issues[END_REF][START_REF] Carmel | Effects of grazing and topography on long-term vegetation changes in a Mediterranean ecosystem in Israel[END_REF][START_REF] Scozzafava | Exploring the effects of land abandonment on habitat structures and on habitat suitability for three passerine species in a highland area of Central Italy[END_REF]. Even if farming activities do not disappear completely, the abandonment of traditional practices of exploitation of timber and wood resources [START_REF] Debussche | Mediterranean landscape changes: evidence from old postcards[END_REF][START_REF] Moreira | Temporal (1958-1995) pattern of change in a cultural landscape of northwestern Portugal: implications for fire occurrence[END_REF] contribute to increasing fire hazard. Reforestations and afforestations, which have been promoted in the Mediterranean region in the last decades, both under the scope of forest policies (e.g. Pausas et al., 2004a), or, more recently, as a policy-driven management alternative in abandoned agricultural land (e.g. [START_REF] Macdonald | Agricultural abandonment in mountain areas of Europe[END_REF]Pausas et al., 2004a), have achieved certain environmental goals (i.e. to increase carbon sink capacity or to stop desertification processes), but have also increased fire hazard when creating large areas with homogeneous even-aged stands of flammable species (cf. § 3.1).

In contrast to the general trend, only a small proportion of the studies, mainly located in coastal areas, provided evidence of decreased fire hazard coupled with the loss of forest and shrubland cover. For example, [START_REF] Serra | Land-cover and land-use change in a Mediterranean landscape: A spatial analysis of driving forces integrating biophysical and human factors[END_REF] described increased agricultural activities and urbanization in a coastal region of southern Spain. Similar patterns were described for coastal areas in Turkey [START_REF] Alphan | Monitoring environmental changes in the mediterranean coastal landscape: the case of Cukurova, Turkey[END_REF], Lebanon [START_REF] Jomaa | Landscape spatial dynamics over 38 years under natural and anthropogenic pressures in Mount Lebanon[END_REF] and Italy [START_REF] Corona | Aerial assessment of landscape net change by means of two-phase network sampling: an application to central Italy[END_REF][START_REF] Falcucci | Changes in land-use/land-cover patterns in Italy and their implications for biodiversity conservation[END_REF].These changes have been driven by the increase of urban, tourist and industrial development, population increases and intensification of agricultural practices (e.g. [START_REF] Serra | Land-cover and land-use change in a Mediterranean landscape: A spatial analysis of driving forces integrating biophysical and human factors[END_REF][START_REF] Tanrivermis | Agricultural land use change and sustainable use of land resources in the mediterranean region of Turkey[END_REF][START_REF] Van Eetvelde | Analyzing structural and functional changes of traditional landscapes-two examples from Southern France[END_REF], including livestock grazing (e.g. [START_REF] Lyrintzis | Human impact trend in Crete: the case of Psilorites Mountain[END_REF].

Depending on the social context in specific regions, some drivers may have a dual effect on fire hazard (Table 1). For example, LULC changes reflected in a hypothetically lowered fire hazard, because of biomass removal, may in fact increase fire risk. These include a more intensive use of pastures associated with an increasing use of fire for pasture renewal [START_REF] Arianoutsou | Aspects of demography in post-fire Mediterranean plant communities of Greece[END_REF][START_REF] Bajocco | Evidence of selective burning in. Sardinia (Italy): Which land-cover classes do wildfires prefer?[END_REF][START_REF] Martinez | Human-caused wildfire risk rating for prevention planning in Spain[END_REF][START_REF] Mouillot | Some determinants of the spatio-temporal fire cycle in a Mediterranean landscape (Corsica, France)[END_REF], or an increased wildland-urban interface due to urban sprawl (e.g. [START_REF] Arianoutsou | Landscape changes in Mediterranean Ecosystems of Greece: implications for Fire and Biodiversity issues[END_REF][START_REF] Curt | Managing road corridors to limit fire hazard. a simulation approach in southern France[END_REF][START_REF] Martinez | Human-caused wildfire risk rating for prevention planning in Spain[END_REF][START_REF] Romero-Calcerrada | Spatial modelling of socioeconomic data to understand patterns of human-caused wildfire ignition risk in the SW of Madrid (central Spain)[END_REF][START_REF] Wittenberg | Spatio temporal perspectives of forest fires regimes in a maturing Mediterranean mixed pine landscape[END_REF]Vasconcelos et al. 2001;[START_REF] Vazquez | Recent fire regime characteristics and potential natural vegetation relationships in Spain[END_REF]. In fact, population density and distance to road networks are the major drivers of ignition risk and recent fire research studies identified the rural-urban interface as the most fire prone areas in Mediterranean countries (Badia-Perpinya and Pallares- [START_REF] Badia-Perpinya | Spatial distribution of ignitions in Mediterranean periurban and rural areas: the case of Catalonia[END_REF][START_REF] Catry | Modelling and mapping wildfire ignition risk in Portugal[END_REF][START_REF] Curt | Managing road corridors to limit fire hazard. a simulation approach in southern France[END_REF][START_REF] Moreira | Regional variations in wildfire susceptibility of land-cover types in Portugal: implications for landscape management to minimize fire hazard[END_REF].

In summary, most observed landscape changes can be described by what Hill et al. (2008) called the "rural exodus syndrome", the widespread increase in vegetation biomass over wide areas of southern Europe and the "strong urbanization tendencies and concentration of population along the coasts and in major cities, contrasting with decreasing population in the hinterlands". This seems to be the main trend across all the European Mediterranean countries, causing increased fire hazard except near the coast and in specific locations where tourism, intensification of agriculture and urban development prevail [START_REF] Hill | Mediterranean desertification and land degradation: Mapping related land use change syndromes based on satellite observations[END_REF][START_REF] Mazzoleni | Recent Dynamics of the Mediterranean Vegetation and Landscape[END_REF]. This overall trend in southern Europe strongly contrasts with that observed in Mediterranean North African countries, where deforestation as a result of grazing, clearing for agriculture, woodcutting for heating and charcoal production [START_REF] Mazzoleni | Recent Dynamics of the Mediterranean Vegetation and Landscape[END_REF], coupled with increasing population, contribute to decreasing fire hazard.

Large fires are becoming more common in the Mediterranean region: the role of weather, landscape patterns and fire suppression policies

Large fires are becoming more frequent

Large fires (LF) are relatively new in the recent history of the Mediterranean Basin [START_REF] Lloret | A comparison of the medieval and the current fire regimes in managed pine forests of Catalonia (NE Spain)[END_REF]. Recent exceptional fire-seasons (e.g. 1978/79 and 1994in Spain, 1998[START_REF] Vélez | La defensa contra incendios forestales: fundamentos y experiencias[END_REF]and 2007in Greece, 2005in Portugal, 2003 throughout Europe) helped to highlight the importance of LF in the Euro-Mediterranean (e.g. [START_REF] Oliveras | Factors influencing the pattern of fire severities in a large wildfire under extreme meteorological conditions in the Mediterranean basin[END_REF][START_REF] Piñol | Climate warming and wildfire hazard and wildfire occurrence in coastal eastern Spain[END_REF][START_REF] Pausas | Changes in fire and climate in the Eastern Iberian Peninsula (Mediterranean Basin)[END_REF]Xanthopoulos, 2007a). LFs represent a small fraction of the total number of fires, but are responsible for a large percentage of the total land area burned in the Mediterranean basin (e. g. [START_REF] Bermudez | Spatial and temporal extremes of wildfire sizes in Portugal[END_REF][START_REF] Diaz-Delgado | Spatial patterns of fire occurrence in Catalonia, NE, Spain[END_REF]. They tend to occur under specific, relatively uncommon synoptic meteorological conditions (like high temperatures, prolonged drought and strong winds), have different behaviour (e. g. higher intensities), have different patterns and spread mechanisms, a lower range of suppression options, and, depending on their rate of recurrence as well as landscape-scale variation in severity, more adverse ecological effects [START_REF] Bermudez | Spatial and temporal extremes of wildfire sizes in Portugal[END_REF][START_REF] Diaz-Delgado | Spatial patterns of forest fires in Catalonia (NE of Spain) along the period 1975-1995. Analysis of vegetation recovery after fire[END_REF][START_REF] Gill | Large fires, fire effects and the fire regime concept[END_REF][START_REF] Pausas | Are wildfires a disaster in the Mediterranean basin? -A review[END_REF][START_REF] Romme | Are large, infrequent disturbances qualitatively different from small, frequent disturbances?[END_REF].

Although some studies reported an increase of LF occurrence in Spain during the last decades [START_REF] Diaz-Delgado | Spatial patterns of fire occurrence in Catalonia, NE, Spain[END_REF][START_REF] Moreno | Recent history of forest fires in Spain[END_REF], others found no evidence of increasing or decreasing trends over time in Portugal [START_REF] Bermudez | Spatial and temporal extremes of wildfire sizes in Portugal[END_REF], in France [START_REF] Amouric | Le feu à l'épreuve du temps[END_REF] or at the European scale during a period of ca. 20 years [START_REF] San-Miguel | Forest fires at a glance: facts, figures and trends in the EU[END_REF], suggesting that regional trends could be quite variable. For example, [START_REF] Bermudez | Spatial and temporal extremes of wildfire sizes in Portugal[END_REF] analysed the occurrence of LF in Portugal during a period of 21 years and found a cyclical pattern of occurrence of extreme fire sizes, with a return period of 3 to 5 years, and argued that this might result from post-fire recovery response of vegetation (i. e. rates of fuel accumulation), more than meteorological or anthropogenic factors. On the contrary, Pausas and Fernandez-Muñoz (in press) showed a large increase in LF occurrence in the 1973-2006 period in Valencia region (Spain), in relation to the 1873-1972 period.

In summary, although the number of fires and total burned area has increased in southern Europe, a clear trend of increasing occurrence of LF is not always the rule, as there is wide geographic variability. However, existing evidence does suggest an increase in LF frequency in several regions, either monotonically or in a cyclic pattern.

Fire weather is more important than landscape pattern in determining fire spread

There is still a debate on whether landscape pattern or meteorological conditions are the fundamental controller of fire spread, or whether temperature alone can explain recent and forecasted trends in fire occurrence in the Mediterranean basin [START_REF] Piñol | Modelling the effect of fire-exclusion and prescribed fire on wildfire size in Mediterranean ecosystems[END_REF]. While in some areas, such as in the boreal forest, it appears that landscape plays a less important role in determining what is burned by fires [START_REF] Podur | The influence of weather and fuel type on the fuel composition of the area burned by forest fires in Ontario, 1996-2006[END_REF], in the Mediterranean region, selectivity by fire towards certain LULC types show that the landscape plays a more critical role in fire spread (e.g. [START_REF] Bajocco | Evidence of selective burning in. Sardinia (Italy): Which land-cover classes do wildfires prefer?[END_REF][START_REF] Moreira | Temporal (1958-1995) pattern of change in a cultural landscape of northwestern Portugal: implications for fire occurrence[END_REF][START_REF] Moreira | Regional variations in wildfire susceptibility of land-cover types in Portugal: implications for landscape management to minimize fire hazard[END_REF]Moreno et al., in press).

Overall, inter annual variability in burned areas is closely linked with annual climate indices of drought, temperature or a combination of both. This has been shown from recent global remote sensing studies (Van der [START_REF] Van Der Werf | Carbon emissions from fires in tropical and subtropical ecosystems[END_REF] and used in global fire models [START_REF] Thonicke | The role of fire disturbance for global vegetation dynamics: coupling fire into a dynamic global vegetation model[END_REF]. In the Mediterranean, these indices remain valid at the landscape [START_REF] Mouillot | Some determinants of the spatio-temporal fire cycle in a Mediterranean landscape (Corsica, France)[END_REF] and regional levels [START_REF] Pausas | Changes in fire and climate in the Eastern Iberian Peninsula (Mediterranean Basin)[END_REF][START_REF] Pereira | Synoptic patterns associated with large summer forest fires in Portugal[END_REF][START_REF] Vazquez | Sensitivity of fire occurrence to meteorological variables in Mediterranean and Atlantic areas of Spain[END_REF][START_REF] Viegas | A relationship between rainfall and burned area for Portugal[END_REF] with as simple indices as summer rainfall explaining a significant proportion of annual variability in total area burned. For example, in Cantabria (north Spain), most fires occur in conjunction with "Suradas", a weather event which combines high winds and low humidity, resulting in high-risk situations [START_REF] Carracedo | An advance of the role of human and natural factors in the genesis of forest fires in Cantabria (Northern Spain)[END_REF]. Extreme fire weather may further promote the occurrence of fire brands and spot fires, leading to indirect climate-related extreme fire events in terms of area burned. In the Mediterranean region, people-ignited fires are largely predominant over natural ignitions, but [START_REF] Vazquez | Patterns of lightning-, and people-caused fires in peninsular Spain[END_REF] showed that the number of lightning fires is also increasing, and this cause was associated to some of the largest recorded fires [START_REF] Moreno | Recent history of forest fires in Spain[END_REF]Moreno 1998). Thus, LF occurrence can be favoured by an increase in natural caused ignitions, eventually even being influenced by solar activity [START_REF] Gomes | Solar activity as a possible cause of large forest fires -A case study: Analysis of the Portuguese forest fires[END_REF].

In spite of this trend for the total area burned being correlated with climate, there is scarce evidence that average (or maximum) fire size increases with harsher fire weather conditions (e.g. [START_REF] Piñol | Climate warming and wildfire hazard and wildfire occurrence in coastal eastern Spain[END_REF] in Spain and Good et al. (2007) in Italy and Greece). Some studies do not even showing a relationship between climate and fire occurrence [START_REF] Fule | Forest structure and fire history in an old Pinus nigra forest, eastern Spain[END_REF][START_REF] Wittenberg | Spatio temporal perspectives of forest fires regimes in a maturing Mediterranean mixed pine landscape[END_REF], confirming that other processes are also involved in fire ignition and spread.

Currently, the relative contribution of weather versus landscape pattern on fire spread in Mediterranean landscapes may be related to thresholds in fire weather that allow (or not) the landscape pattern to arise as a driver enhancing or, in particular, inhibiting fire spread. Under moderate fire spread conditions, fires tend to be smaller, and fuel spatial patterns would exert a stronger control on fire spread. Thus a higher selectivity towards flammable fuels would be expected. Extreme fire weather could produce large wildfires whose spread is not determined by landscape structure [START_REF] Salvador | Does fire occurrence modify the probability of being burned again? A null hypothesis test from Mediterranean ecosystems in NE Spain[END_REF][START_REF] Moritz | Spatial variation in extreme winds predicts large wildfire locations in chaparral ecosystems[END_REF]. In the past the situation may have been different. In a recent study, Pausas and Fernandéz-Muñoz (in press) suggested that fire regime changes in the western Mediterranean were different before the 1970s, where fires were mostly fuel-limited, from the present, where they are mostly drought-driven.

Fire suppression policies increase large fire occurrence?

Fire suppression policies can also lead to fuel accumulation and LF outbreaks (e.g. [START_REF] Oliveras | Relationships among number of fires, total area burnt, and large fires in southern France, eastern Spain and Portugal[END_REF]. [START_REF] Piñol | Modelling the effect of fire-exclusion and prescribed fire on wildfire size in Mediterranean ecosystems[END_REF] used a model of vegetation dynamics and fire spread, calibrated with real data from 2 areas in the Iberian Peninsula, to evaluate the effect of different fire fighting capacities on LF occurrence. Interestingly, their simulations showed that higher fire-fighting capacities, or a lower number of ignitions, resulted in the same total annual area burned but with a higher proportion of LF. In fact, the reinforced funds on fire suppression policies observed in Mediterranean countries (especially after disastrous fire seasons), if not combined with fuel management, seem to be effective at reducing small fires, but not large ones [START_REF] Diaz-Delgado | Spatial patterns of fire occurrence in Catalonia, NE, Spain[END_REF][START_REF] Duguy | Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)[END_REF]González and Pukkala, 2007;Xanthopoulos, 2007bXanthopoulos, , 2008a)). Events in Greece since the dramatic fire season of 2000 are a good example for this. As warned by some (e. g. [START_REF] Xanthopoulos | Forest fires in Greece: Past, present and future[END_REF]Xanthopoulos, , 2007c)), a strong fire suppression policy implemented in the 2001-2006 period, that temporarily appeared to be successful, did not solve the country's fire problem. In 2007 Greece experienced its worst fire season ever, with fires exceeding 20000-30000 ha mainly as a result of fuel accumulation.

Higher fire frequency in specific topographic locations and previously burned areas is creating homogeneous landscapes covered by shrublands

Contrary to what could be expected from the fuel-age paradigm, which states that fuel reduction as a consequence of wildfires would reduce the risk of future fires [START_REF] Zedler | Age mosaics and fire size in chaparral: a simulation study[END_REF], there is evidence that areas previously burned are characterized by a higher probability to burn when compared to areas that were never burned. So, it seems that previous fires determine conditions that favour a new fire in a relatively short time period. The repeated burning phenomenon might be interpreted as a result of several spatial legacies influencing fire occurrence, nested within each other, and resulting in a strong spatial dependence of fire on previously burned areas. The mechanisms that might contribute to and the consequences of repeated burning are summarised below.

Fire hazard is higher in specific topographic locations

Topography (altitude, exposure, slope) can affect fire frequency and rate of spread. The causes behind these topographic effects can be grouped into fire ignition patterns, fire behavior (in particular rate of spread), and fuel biomass. Disentangling these processes is not easy, as they are interrelated and dependent on the spatial scale (i.e., grain and extent). In fact, topography interacts with local wind direction, microclimates and, in turn, vegetation type, fuel loads and moisture content. Several studies have shown topographic influences on vegetation composition and structure (Fontaine et al., 2007;[START_REF] Rescia | Influence of landscape complexity and land management on woody plant diversity in northern Spain[END_REF], transpiration and desiccation conditions [START_REF] Rana | Measurement and modelling of evapotranspiration of irrigated citrus orchard under Mediterranean conditions[END_REF][START_REF] Van Der Trol | Topography induced spatial variations in diurnal cycles of assimilation and latent heat of Mediterranean forest[END_REF], vegetation dynamics [START_REF] Carmel | Comparing landscape scale vegetation dynamics following recent disturbance in climatically similar sites in California and the Mediterranean basin[END_REF][START_REF] Mouillot | Long-term forest dynamic after land abandonment in a fire prone Mediterranean landscape (central Corsica, France)[END_REF], fire severity [START_REF] Broncano | Topography and forest composition affecting the variability in fire severity and post-fire regeneration occurring after a large fire in the Mediterranean basin[END_REF], and post-fire vegetation regeneration [START_REF] Peñuelas | Migration, invasion and decline: changes in recruitment and forest structure in a warming-linked shift of European beech forest in Catalonia (NE Spain)[END_REF][START_REF] Baeza | Human disturbance and environmental factors as drivers of long-term post-fire regeneration patterns in Mediterranean forests[END_REF]. Furthermore, some of the observed topographic effects on fire occurrence can be explained by human activities (e.g. [START_REF] Carmo | Land use and topography influences on wildfire occurrence in northern Portugal[END_REF][START_REF] Catry | Modelling and mapping wildfire ignition risk in Portugal[END_REF][START_REF] De La Cueva | Recent fire regime in peninsular Spain in relation to forest potential productivity and population density[END_REF][START_REF] Martinez | Human-caused wildfire risk rating for prevention planning in Spain[END_REF][START_REF] Romero-Calcerrada | Spatial modelling of socioeconomic data to understand patterns of human-caused wildfire ignition risk in the SW of Madrid (central Spain)[END_REF][START_REF] Salvador | Does fire occurrence modify the probability of being burned again? A null hypothesis test from Mediterranean ecosystems in NE Spain[END_REF]. As an example, in some regions higher probabilities of ignitions have been estimated at higher altitudes, because of a higher likelihood of lighting and human use of fire for the management of pastures for livestock [START_REF] Catry | Modelling and mapping wildfire ignition risk in Portugal[END_REF][START_REF] Kilinc | The spatial and temporal distribution of lightning strikes and their relationship with vegetation type, elevation, and fire sears in the Northern Territory[END_REF]Price and Ride, 1994;[START_REF] Vazquez | Patterns of lightning-, and people-caused fires in peninsular Spain[END_REF]. In other locations, high ignition risk is associated with flat and lower elevated areas because of the high density and proximity to road networks, human settlements and urban interfaces (Vasconcelos et al., 2001).

As a result, several studies have provided evidence of significant spatial pattern of fire recurrence associated with certain topographic positions across the Mediterranean region. For example, [START_REF] Mouillot | Some determinants of the spatio-temporal fire cycle in a Mediterranean landscape (Corsica, France)[END_REF] found that south facing slopes and ridge crests burned more frequently than other positions in Corsica (France). Similar patterns were observed by [START_REF] Vazquez | Spatial distribution of forest fires in Sierra de Gredos (Central Spain)[END_REF] in Spain, and [START_REF] Trabaud | Effects of fire frequency on plant communities and landscape pattern in the Massif de Aspres (southern France)[END_REF] in the French Pyrenees. Fire spread simulation models, such as FARSITE [START_REF] Finney | Elevation and exposition rather than soil types determine communities and site suitability in Mediterranean mountain forests of southern Anatolia, Turkey[END_REF], and FIRETEC, recently applied for Mediterranean landscapes in Italy [START_REF] Arca | Evaluation of FARSITE simulator in Mediterranean maquis[END_REF]), middle East [START_REF] Carmel | Assessing fire risk using Monte Carlo simulations of fire spread[END_REF], Spain [START_REF] Duguy | Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)[END_REF] and France [START_REF] Pimont | Validation of FIRETEC windflows over a canopy and a fuel-break[END_REF] have highlighted the intrinsic preference for fire spread towards certain topo-climates as high altitudes and uphill directions where local winds, usually blowing toward the ridge top in the daytime, enhanced the topographical effect [START_REF] Boboulos | Wind and slope effects on ROS during the fire propagation in East-Mediterranean pine forest litter[END_REF].

Fire frequency is creating homogeneous areas covered by shrublands

Some pine forests have a low resilience to increased fire frequency. For example, Pinus halepensis and P. pinaster forests in eastern and Central Spain show very low resilience when burned frequently, turning into shrublands in the medium to long term after fire (e.g. [START_REF] Baeza | Human disturbance and environmental factors as drivers of long-term post-fire regeneration patterns in Mediterranean forests[END_REF][START_REF] Pausas | Are wildfires a disaster in the Mediterranean basin? -A review[END_REF]. The same was shown by [START_REF] Arianoutsou | Land-use interactions with fire in Mediterranean Pinus halepensis landscapes of Greece: patterns of biodiversity[END_REF] for Pinus halepensis forests in central Greece. The reason behind this shift is related to the characteristics of the reproductive biology of these pines [START_REF] Arianoutsou | Aspects of demography in post-fire Mediterranean plant communities of Greece[END_REF]. Pinus halepensis individuals reach their full reproductive capacity when 15-20 years old by having a canopy seed bank in their serotinous cones. Hence, when a fire occurs over a previously burned pine stand with a return period shorter than this time window, pines will not regenerate and the structure of vegetation communities is changed to one dominated by grasses and shrubs [START_REF] Eugenio | Recruitment and growth decline in Pinus halepensis populations after recurrent wildfires in Catalonia (NE Iberian Peninsula)[END_REF][START_REF] Kazanis | Long-term post-fire vegetation dynamics in Pinus halepensis forests of Central Greece: A functional group approach[END_REF][START_REF] Kazanis | Characterization of fire vulnerable Pinus halepensis ecosystems in Spain and Greece[END_REF][START_REF] Kazanis | Assessing the effect of reduced fire interval on Pinus halepensis Mill. communities: a comparative study from Spain and Greece[END_REF][START_REF] Lloret | Responses of Mediterranean plant species to different fire frequencies in Garraf Natural Park (Catalonia, Spain): field observations and modelling[END_REF] (Fig. 2). A similar pattern should be expected for Pinus brutia forests.

# Figure 2 approximately here

Other fire-sensitive pine species as Pinus nigra and Pinus sylvestris which are not serotinous, do not have any specific adaptation to cope with fire and their recovery is mainly dependent upon the seed dispersal from unburned patches [START_REF] Arianoutsou | Effects of fire on high altitude coniferous forests of Greece[END_REF][START_REF] Buhk | The challenge of plant regeneration after fire in the Mediterranean Basin: scientific gaps in our knowledge on plant strategies and evolution of traits[END_REF][START_REF] Eugenio | Fire recurrence effects on the structure and composition of Mediterranean Pinus halepensis communities in Catalonia (northeast Iberian Peninsula)[END_REF][START_REF] Eugenio | Recruitment and growth decline in Pinus halepensis populations after recurrent wildfires in Catalonia (NE Iberian Peninsula)[END_REF][START_REF] Retana | Regeneration patterns of three Mediterranean pines and forest changes after a large wildfire in northeastern Spain[END_REF][START_REF] Rodrigo | Direct regeneration is not the only response of Mediterranean forests to large fires[END_REF][START_REF] Rodrigo | Fire reduces Pinus pinea distribution in the northeastern Iberian Peninsula[END_REF]. In the case of some deciduous oak communities, the recovery process after fire is very low, and more than 50-60 years are needed to reach the pre-fire conditions [START_REF] Calvo | The dynamics of mediterranean shrubs species over 12 years following perturbations[END_REF][START_REF] Jacquet | Measuring the postfire resilience of a bird-vegetation system: a 28-year study in a Mediterranean oak woodland[END_REF]. During the initial stages (0-20 years) homogeneous shrubland communities dominate spatially and influence negatively the growth of Quercus pyrenaica [START_REF] Alvarez | Spatial and temporal patterns in structure and diversity of Mediterranean forest of Quercus pyrenaica in relation to fire[END_REF][START_REF] Calvo | The dynamics of mediterranean shrubs species over 12 years following perturbations[END_REF]. Hence, short fire intervals could favour the expansion of shrublands communities or the persistence of resprouting oak forests with a shrubland-type physiognomy (Fig. 2). Even for some evergreen oaks (as Quercus suber and Quercus ilex) that show vigourous resprouting after fire and a quick recovery [START_REF] Debussche | Changes in the vegetation of Quercus pubescens woodland after cessation of coppicing and grazing[END_REF][START_REF] Espelta | Resprouting patterns after fire and response to stool cleaning of two coexisting Mediterranean oaks with contrasting leaf habits on two different sites[END_REF], high fire frequencies may decrease such ability [START_REF] Diaz-Delgado | Satellite evidence of decreasing resilience in Mediterranean plant communities after recurrent wildfires[END_REF]Trabaud and Galtie 1996). Finally, in burned old croplands postfire succession is mostly limited to obligate-seeders, a process that has resulted in the spread of Mediterranean gorse shrublands (Ulex parviflorus) in some areas, increasing the risk and severity of fires [START_REF] Baeza | Human disturbance and environmental factors as drivers of long-term post-fire regeneration patterns in Mediterranean forests[END_REF] (Fig. 2).

Fire frequency is higher in previously burned areas

Several authors have documented high fire recurrence in previous burned areas across several Mediterranean countries. For example, in central Corsica (France), some areas were burned up to 7 times from 1957 to 1997 [START_REF] Mouillot | Some determinants of the spatio-temporal fire cycle in a Mediterranean landscape (Corsica, France)[END_REF]. In Catalonia (Spain), ca. 12% of the total areas burned during 1975-1998 burned twice during this period [START_REF] Diaz-Delgado | Spatial patterns of fire occurrence in Catalonia, NE, Spain[END_REF]. In an area of Central Spain, the forests that burned twice in the years 1970-1990 accounted for about the 7% of the total forest area burned [START_REF] Vazquez | Spatial distribution of forest fires in Sierra de Gredos (Central Spain)[END_REF]. In Italy, 60% of the forest fires in the period 2005-2009 occurred in areas that had been burned in the past ten years (CFS, 2005(CFS, , 2006(CFS, , 2007(CFS, , 2008(CFS, , 2009)).

As was mentioned in the previous section, one first explanatory mechanism for this increased fire recurrence is the low resilience of some forest types which prevents auto-succession, and favours the establishment of more fire-prone fuel types [START_REF] Acácio | Are drought and wildfires turning Mediterranean cork oak forests into persistent shrublands?[END_REF][START_REF] Lloret | Wildfires and landscape patterns in the Eastern Iberian Peninsula[END_REF][START_REF] Lloret | Responses of Mediterranean plant species to different fire frequencies in Garraf Natural Park (Catalonia, Spain): field observations and modelling[END_REF][START_REF] Pérez | Methods for quantifying fire severity in shrubland-fires[END_REF]) (Fig. 3). Secondly, surface fuel loads recover very quickly after fire, often exceeding pre-fire amounts. For example, in non-salvaged burned forests, hazardous fuel production is a function of the decay and fall of fire-killed snags driving accumulation of both coarse and fine woody debris [START_REF] Keyser | Short-term impact of post-fire salvage logging on regeneration, hazardous fuel accumulation and understory development in ponderosa pine forests of the Black Hills, SD, USA[END_REF]. In other burned areas, highly flammable tussock grasses (some of which are alien) can replace locally dominating woody species, resulting in increasing frequencies of very large and intense fires [START_REF] Grigulis | Landscape-scale positive feedbacks between fire and expansion of the large tussock grass, Ampelodesmos mauritanica in Catalan shrublands[END_REF][START_REF] Vilà | Positive fire-grass feedback in Mediterranean Basin woodlands[END_REF]. Several studies have confirmed that the recovery rate of scrub cover after fire was quite rapid, often exceeding the pre-fire biomass amount [START_REF] Hernandez-Clemente | Analysis of postfire vegetation dynamics of Mediterranean shrub species based on terrestrial and NDVI data[END_REF][START_REF] Roder | Using long time series of Landsat data to monitor fire events and post-fire dynamics and identify driving factors[END_REF][START_REF] Viedma | Modeling rates of ecosystem recovery after fires by using Landsat TM data[END_REF]. Simulation models such as FATELAND and BROLLA have shown an increase in shrublands as a response to increased fire frequency, creating a state of successional stagnation which may enhance the positive shrub-fire feedback [START_REF] Pausas | Response of plant functional types to changes in the fire regime in Mediterranean ecosystems: A simulation approach[END_REF][START_REF] Pausas | Spatial and temporal patterns of plant functional types under simulated fire regimes[END_REF] (Fig. 3).

# Figure 3 approximately here

Thirdly, fire disturbance creates more connected and homogeneous vegetation patches (fuel continuity) that favours fire spread and future fires [START_REF] Chuvieco | Measuring changes in landscape pattern from satellite images: short-term effects of fire on spatial diversity[END_REF][START_REF] Lloret | Wildfires and landscape patterns in the Eastern Iberian Peninsula[END_REF][START_REF] Loepfe | Feedbacks between fuel reduction and landscape homogenisation determine fire regimes in three Mediterranean areas[END_REF][START_REF] Van Leeuwen | Monitoring post-wildfire vegetation response with remotely sensed time-series data in Spain, USA and Israel[END_REF][START_REF] Viedma | Interactions between land use/land cover change, forest fires and landscape structure in Sierra de Gredos (Central Spain)[END_REF]. Shrublands form large patches of fuel of the same age because the post-fire fuel build-up is rapid [START_REF] Baeza | Vegetation recovery after fuel management in Mediterranean shrublands[END_REF]. Furthermore, spatial patterning of fire severity and associated fire-induced vegetation mortality can increase the amount and continuity of dead fuels contributing to reburning [START_REF] Collins | Spatial patterns of large natural fires in Sierra Nevada wilderness areas[END_REF]. However, it is also recognized that variations in fire severity can enhance landscape heterogeneity creating patches with different successional stages [START_REF] Lloret | Wildfires and landscape patterns in the Eastern Iberian Peninsula[END_REF][START_REF] Pérez | Effects of the recent land-use history on the postfire vegetation of uplands in Central Spain[END_REF][START_REF] Trabaud | Effects of fire frequency on plant communities and landscape pattern in the Massif de Aspres (southern France)[END_REF] and unburned patches within fire scar perimeters [START_REF] Koutsias | Logistic regression modelling of multitemporal Thematic Mapper data for burned area mapping[END_REF] that can alter the probability of reburning. In general, the effects of fire on landscape may vary from region to region because of differences in local fire history, regeneration patterns among main land covers and topographic constraints [START_REF] Viedma | The influence of topography and fire in controlling landscape composition and structure in Sierra de Gredos (Central Spain)[END_REF]. Finally, the loss of value that people give to burned lands reinforced these positive feedbacks leading to increased fire frequencies (Blasi et al., 2004;[START_REF] Vazquez | Spatial distribution of forest fires in Sierra de Gredos (Central Spain)[END_REF]. There is a social perception that burned areas are less valuable which, in the absence of proper conservation strategies, makes them more prone to land abandonment or misuse (e.g. grazing, pastoral burning) with the effects already discussed. This might potentially lead frequently burned areas to a spiral towards deforestation [START_REF] Arianoutsou | Desertification by overgrazing in Greece: the case of Lesvos island[END_REF] that will, in turn, create shrub-dominated landscapes with higher fire risk [START_REF] Espelta | Recurrent wildfires constrain long-term reproduction ability in Pinus halepensis Mill[END_REF] (Fig. 3).

Landscape fuel breaks are not always effective tools to reduce fire hazard under extreme weather conditions

Fuel management strategies

Fuel management can be implemented using three main strategies, respectively isolation by fuel breaks, area-wide fuel modification and fuel type conversion [START_REF] Rigolot | Managing wildfire risk: prevention, suppression[END_REF]. The isolation by fuel break strategy has been the most used, and involves compartmentalising large areas of fire prone fuel types with a network of strips where fuel has been manipulated with the objective of helping fire fighters to (i) break up the continuity of hazardous fuels across a landscape; (ii) reduce the intensity of wildfires, providing broad zones within which fire-fighters can conduct suppression operations more safely and efficiently; (iii) provide strips to facilitate subsequent area-wide fuel treatments; and (iv) provide various non-fire-related benefits (e.g. habitat diversity, landscape scenery) [START_REF] Agee | The use of shaded fuelbreaks in landscape fire management[END_REF][START_REF] Cumming | Forest type and wildfire in the Alberta boreal mixedwood: what do fires burn?[END_REF][START_REF] Rigolot | Fuel-break assessment with an expert appraisement approach[END_REF][START_REF] Weatherspoon | Landscape-level strategies for forest fuel management[END_REF]. This strategy has been implemented in southern Europe in the last decades, mainly in France, Portugal, and Spain, and to a lesser extent in Italy and Greece and Turkey [START_REF] Bilgili | Forest fires and fire management policies in Turkey. Procceedings FAO Meeting on Public Policies Affecting Forest Fires[END_REF][START_REF] Xanthopoulos | Forest Fuels Management in Europe[END_REF].

Area-wide fuel modifications are an extensive application of fuel treatments at the forest stand level that include reduction of fuel load, increased fuel compactness and disruption of vertical and horizontal fuel continuity [START_REF] Chandler | Forest fire management and organization[END_REF]. Although it is much less strategically planned than fuel break networks, it may complement it by working inside the landscape units isolated by the fuel break network. The patchy pattern of fuel treatments creates a landscape mosaic that increase its resistance to fire spread by the limitation of ladder fuels (Velez 1990(Velez , 2000)).

Fuel type conversion involves replacing highly flammable vegetation by low growing, less hazardous species [START_REF] Rigolot | Managing wildfire risk: prevention, suppression[END_REF]. Real fuel type conversion towards fire resistant vegetation is mostly limited to wildland-urban interfaces where landowners can choose less flammable ornamental (preferably native) species. In wildland areas, natural succession can be used where site conditions enable it to promote a mixture of species and to favour mature stages (Velez, 1990). This naturally slow process can be somewhat speeded up with some selective thinning favouring broadleaved species. [START_REF] Duché | (coord.) Conception des Coupures de combustible[END_REF] distinguish three main objectives for fuel breaks: to decrease fire ignition events, to decrease total burned area and to decrease fire effects on people, human resources and ecosystems. Thus, fuel break design and evaluation of effectiveness will differ depending on the objectives. Clearly, the effectiveness of fuel management in general and of landscape fuel breaks in particular can not be solely assessed by fire size reduction and effective fire suppression, but it should also take into account the benefits for fire suppression actions and the reduction of the environmental and the socio-economical impact of wildfires.

Assessing fuel break effectiveness

Several approaches have been used for assessing the effectiveness of fuel control techniques for fire hazard reduction (e.g. [START_REF] Fernandes | A review of prescribed burning effectiveness in fire hazard reduction[END_REF] or for decreasing wildfire intensity and severity [START_REF] Rigolot | Fuel-break assessment with an expert appraisement approach[END_REF]. The expert appraisement approach uses the experience of highly skilled fire professionals to provide standards for fuel break building and maintenance based on the best knowledge and practices [START_REF] Rigolot | Evaluation de l'efficacité des coupures de combustible par deux approches : dires d'experts et modélisation[END_REF]. Experimental fires can be used to test the probability of fuel break crossing, depending on fire intensity [START_REF] Davidson | Predicting the effectiveness of firebreaks[END_REF] or to assess fuel-break dimensions [START_REF] Wilson | Width of firebreak that is necessary to stop grass fires: some field experiments[END_REF]. The experimental approach is risky and it is almost impossible to test the highest part of fire intensity scale [START_REF] Davis | The economics of wildfire protection with emphasis on fuel break systems[END_REF]. Computer simulations using fire behaviour or fire growth models have been successfully used for assessing the effectiveness of silvicultural and fuel treatment scenarios [START_REF] Duguy | Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)[END_REF]. Finally, analysing in the field situations where fuel breaks have been hit by wildfires strongly contributes to an efficient fuel-break design [START_REF] Lambert | Analyse après incendie de six coupures de combustible[END_REF][START_REF] Rigolot | Learning from fuel-break behaviour during the 2003 large fires in South Eastern France[END_REF].

Field studies devoted to assessing the effectiveness of fuel breaks in controlling fire size have been carried out in south eastern France during 1993[START_REF] Tanrivermis | Agricultural land use change and sustainable use of land resources in the mediterranean region of Turkey[END_REF][START_REF] Lambert | Analyse après incendie de six coupures de combustible[END_REF]Perchat and Rigolot, 2005;[START_REF] Rigolot | Learning from fuel-break behaviour during the 2003 large fires in South Eastern France[END_REF]. On the whole, 28 fuel breaks have been analysed including a large variety of situations (topographic situation, width, vegetation types, weather conditions, alignment of fuel break with fire front). The difficulties met by suppression forces to arrive and fight the fire in the fuel break network, as well as the ability of homogeneous fuel break segments in containing fire were assessed. In all these studies, the key factors of fuel breaks success were the quality of fuel break design and maintenance, the early fire detection and the good knowledge of the fuel break network by fire-fighters. Factors of failure were late arrival of suppression forces and fuel break discontinuities due to legal restrictions on fuel management or weak points due to topographic or fuel control difficulties. Under extreme fire weather conditions (e.g., the 2003 fire season), fuel breaks perpendicular to fire propagation could never contain the fire front and were crossed over by surface fires in the absence of ground suppression forces and by heavy fire spotting. On the contrary, flank fuel breaks could systematically limit the lateral extension of wildfires, even under extreme fire conditions. But in general, fuel break design and maintenance standards [START_REF] Rcc | Du plan départemental à la coupure de combustible : Guide méthodologique et pratique[END_REF] were effective for moderate to severe fire weather conditions, providing suppression forces were present on the spot.

The case studies approach is constrained by the low number of fires versus fuel break situations encountered and limited data available to analyse them. The simulation approach enables to broaden the range of possible situations and to test innovative fuel break designs. Analyses from simulation models, (e.g. the physically-based fire propagation model FIRETEC) assessed the impact of fuel break vegetation structure on fire behaviour [START_REF] Dupuy | Fire start and spread[END_REF]. Using the same model, [START_REF] Pimont | Effects of vegetation description parameters on forest fire behavior with FIRETEC[END_REF][START_REF] Pimont | Validation of FIRETEC windflows over a canopy and a fuel-break[END_REF] explored the effect of tree layer cover in the likelihood of crowning fire and fire rate of spread. At landscape management scale, and using the spatially explicit fire growth model FARSITE, [START_REF] Duguy | Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)[END_REF] showed that different fuel scenarios may be successful in relation to fire size control: the fragmentation of a fire prone matrix with patches in different successional stages, the introduction of narrow corridors between wooded patches and the promotion of convoluted perimeters were effective in reducing fire size. In some northern Mediterranean regions, the local administration is using FARSITE as a tool for predicting consequences of fuel management options on fire growth [START_REF] Duguy | Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)[END_REF].

Concluding remarks: landscape management and policy implications

The main implications of the findings from scientific research for policy and landscape management are summarised in Table 2. We have identified four main challenges to address, that need specific landscape management and policy guidelines.

# Table 2 approximately here

Reverse the detrimental implications of land cover changes and manage LULC to reduce fire hazard

Population decline, agricultural and pastoral land abandonment (and the subsequent natural regeneration of forests), and policies promoting forest cover, particularly in former agricultural land, are driving the "rural exodus syndrome" [START_REF] Hill | Mediterranean desertification and land degradation: Mapping related land use change syndromes based on satellite observations[END_REF] and causing a widespread increase in vegetation biomass over large areas of the Mediterranean Europe, mainly in mountain areas, and a subsequent increase in fire hazard. This trend can only be counteracted effectively through the creation of policies enabling the improvement of the socio-economic conditions of people living in rural areas, promoting new immigration to these regions, and implementing rural development policies that foster activities contributing to reduce fire hazard, such as agriculture and livestock grazing. These policies are mainly related to agricultural, rural development and economic issues, rather than forest management. For example, the European Agriculture Fund for Rural Development (EAFRD) (EC 1698/2005 of 20 September 2005) could contribute to achieve these objectives in disadvantaged rural areas by: a) improving the competitiveness of agriculture and forestry activities; (b) improving the quality of life by the diversification of economic activity, and c) supporting land management strategies.

In relation to land management strategies, there is conclusive evidence that agricultural areas are the least fire-prone LULC, whereas shrublands are particularly fire prone. This general pattern highlights the relationships between agricultural abandonment and fire hazard in the Mediterranean, as the land-cover types more avoided by fire (agricultural crops) are progressively replaced, in many cases, by the most fire-prone land cover type (shrublands). So, there is a need to define policies to maintain farming activities in areas where landscape planning identified as priority sites for fuel reduction, such as areas surrounding villages or pastoral activities in landscape fuel breaks. In fact, one of the most serious consequences of the abandonment of traditional practices is that villages in mountain areas, traditionally surrounded by a belt of farmland that acted as a landscape fuel break, nowadays have forests and shrublands in the vicinity of houses and other infrastructures, which greatly increase fire hazard. Agro-environmental activities should continue to play a prominent role in supporting the sustainable development of rural areas and in responding to society's increasing demand for environmental services. In general, there is a need for reinforcement of the existing laws and regulations on fuel management around buildings and villages, either through farming or other types of fuel reduction techniques.

Prescribed fire or controlled pastoral fire, or energy policies supporting the environmentally compatible use of renewable bio-energy potential from agriculture and forestry (agricultural waste, crop mix for biomass production, complementary fellings and residues from silvicultural activities and/or fuel management) may also contribute to reducing fire hazard, while providing job opportunities to rural populations. Appropriate use of fire by rural communities coupled with the development of prescribed burning undertaken by fire professionals may be used in integrated fire management [START_REF] Silva | Towards Integrated Fire Management -Outcomes of the European Project Fire Paradox[END_REF]. In the Mediterranean countries, traditional use of fire is associated with rangeland management and other rural activities like burning agroforestry remains and game management. When not used under legal regulation and good practices, traditional use of fire may be a significant cause of wildfires [START_REF] Xanthopoulos | Forest Fuels Management in Europe[END_REF]. On the other hand, in some regions good practices in traditional burning should be maintained and this activity needs to be recognized, consolidated and regulated as part of a community based fire management approach [START_REF] Silva | Towards Integrated Fire Management -Outcomes of the European Project Fire Paradox[END_REF]. Under this new framework, traditional burning may fully contribute to fuel management at the landscape level (Rego et al., 2010b). Recent studies have shown the possible renewal of active rangeland management in south eastern France, with the clear objective of wildfire mitigation [START_REF] Etienne | Browse impact in silvopastoral systems participating in fire prevention in the French Mediterranean region[END_REF]. [START_REF] Beylier | Une coupure de combustible en Luberon: bilan de douze ans de suivis pastoralistes, DFCI et environnementaux[END_REF] showed the successful contribution of sheep grazing to fuel control on both a fuel break network and neighbouring areas in the Luberon Natural Park (France). [START_REF] Thavaud | Guide pratique pour l'entretien des coupures de combustible par le pastoralisme[END_REF] provided practical guidelines for reactivating rangeland management in various ecosystems of the Mediterranean area. They combine new establishments of livestock farmers in fire prone areas, together with consolidation of existing animal farming.

In areas where there are no possibilities of promoting agricultural or pastoral activities, one other alternative to manage shrublands is to carry out afforestations with less fire prone tree species. In terms of forest planning, preference should be given to deciduous broadleaved and mixed forests, usually less fire prone than pine stands or plantations of exotic species. Afforestation policies promoting large scale monocultural stands in former agricultural areas is highly detrimental for fire hazard at the landscape level. Thus, priority should be given to the creation of mosaics of smaller (less than 30 ha) non-contiguous forest patches. Moreira F., Viedma O., Arianoutsou M., Curt T., Koutsias N., Rigolot E., Barbati A., Corona P., Vaz P., Xanthopoulos G., Mouillot F. and Bilgili E. (2011) Landscape -wildfire interactions in Southern Europe: implications for landscape management, Journal of Environmental Management, vol. 92, 2389-2402, Author-produced version

Being prepared for large fires and aim at reducing damage rather than reducing area burned

Large fires are becoming more frequent, at least in some regions. Available evidence indicates that we do not have the technical capabilities to avoid large fires and that they will spread irrespective of LULC planning under extreme fire weather. Even if we tried to increase our technical suppression capacity more, we would simply increase the level at which fuel accumulation creates fire danger conditions that surpass the new suppression capacity. The implication of this is that under certain climatic and fuel load conditions, wildfires will always occur. Strange as it may be to policy makers, fire suppression policies can lead to fuel accumulation and large fire outbreaks. Thus, current fire policies in Mediterranean countries, directed towards reducing the number of ignitions, or having effective fire fighting abilities, will not decrease the number of large wildfires. Stakeholders and managers have to realise that fire-fighters can extinguish most of the fires, but when there is one beyond the extinction capacity, or when the fire-fighting system collapses because of the large number of concurrent ignitions, a large area will be burned because of the high fuel load resulting from successful fire suppression in previous years. Currently, the unbalanced fire management in Europe, with too much resources being allocated to pre-suppression and suppression actions compared to poor fuel management measures (e.g. [START_REF] Fernandes | Forest fires in Galicia (Spain): The outcome of unbalanced fire management. Letter to the editor[END_REF], is increasingly questioned. A major shift in the way fire management is seen requires a cross-sectoral approach integrating agricultural, forest and urban policies. Simultaneously, the "learning to live with fire" objective is increasingly shared [START_REF] Birot | The need for strategy anticipating climate … and other changes[END_REF], recognising that fire cannot be excluded from the Mediterranean environment (Rego et al., 2010a). Under this objective, fuel management is not only devoted to limiting wildfire spread, but also to lowering fire impacts on human resources and assets. This new forest management and planning vision also supposes increasing preparedness and response capacity to fire events, especially at the wildlandurban interface [START_REF] Lampin-Maillet | Wildland urban interface, fire behaviour and vulnerability: characterization, mapping and assessment[END_REF]. In the latter, forest and urban planning should be tuned together and citizens living in fire risk areas should also become part of the solution, by building and preparing their homes for the arrival of fire, as well as being well-informed for fire-response planning (defence and evacuation). The contrasting damages caused by two neighbouring simultaneous fires in poorly versus well planned wildland-urban interface settlements near Athens are the best possible argument for planners and convincing proof for people (Xanthopoulos, 2008b).

The success of policies and management has to be evaluated firstly by the amount of damage caused, rather than by the number of hectares burned. Reducing fire damage will be attained by reducing fuel loads and the vulnerability of the values at risk. This means better planning of locations of houses and villages, promoting policies to avoid the increase of the rural-wildland interface, greater awareness of citizens, and the enforcement of existing laws and regulations on fuel management around buildings and villages [START_REF] Silva | Towards Integrated Fire Management -Outcomes of the European Project Fire Paradox[END_REF].

Increase landscape heterogeneity and decrease the probability of repeated burning

The fact that Mediterranean fire-prone landscapes are increasingly covered by homogeneous shrublands that promote further wildfires creates a dangerous feedback mechanism that has to be stopped. In general, fire propagation may be favoured in landscapes that are homogeneous and hindered at places of greater heterogeneity, and where discontinuities occur. This knowledge can be used in landscape planning, by promoting a diversity of LULC. At the landscape management level, the interspersion of land uses with different fuel loads will counterbalance this trend promoting landscape heterogeneity. In forested regions, this could also be achieved through the spatial planning of stands with different ages to increase fuel load heterogeneity. Furthermore, controlling human behaviour through a better regulation of the use of fire for pastoral burning, particularly by avoiding burning recovering forest patches, could be a first policy measure. In terms of fire prevention in forested areas, top priority should be given to protect forests that have limited post-fire regeneration ability, namely (a) immature Pinus brutia, Pinus halepensis and Pinus pinaster forests, (b) Pinus nigra and Pinus sylvestris forests, and (c) other forest types with scarce distribution and high conservation value, and for which there is evidence of lack of any active post fire response mechanisms, such as the Abies forests of Mediterranean mountains [START_REF] Arianoutsou | Effects of fire on high altitude coniferous forests of Greece[END_REF]. Finally, Mediterranean oak forests, that take longer to recover, will not be able to reach maturity unless fire frequency in these ecosystems is highly reduced.

Combine landscape compartmentalization with self-protection options

Under moderate to severe fire weather conditions, fuel management should be focused on increasing the fire suppression options and effectiveness by limiting fire ignition and fire spread in strategic locations. This is what we call compartmentalization, the division of the landscape into blocks that should set a maximum fire size. However, under exceptional weather conditions, the differences of combustibility among land covers will decrease, and fire may propagate throughout a whole landscape regardless of land cover and fuel management. Increasing indirect fire-fighting capability through improved use of backfire and burn-out operations may help achieve better results in controlling maximum fire size taking advantage of compartmentalization [START_REF] Miralles | Towards Integrated Fire Management -Outcomes of the European Project Fire Paradox[END_REF]. However, that can never be assured. Thus, under extreme fire weather conditions, prevention strategy should move to self-protection options by limiting fire intensity and damages on both ecosystems and human assets, and assuming that fire fighting will not always be possible under these circumstances.

The implementation of a fuel break network requires a fire management plan at the landscape level. Landscape fragmentation is ensured by primary and secondary fuel break networks, the former being strategically located (e.g. ridge top fuel breaks) for increasing the efficiency of fire suppression actions, and the latter for guaranteeing the safe accessibility to the former. Following European standards, strategic fuel break width should be not less than 100 m [START_REF] Rcc | Du plan départemental à la coupure de combustible : Guide méthodologique et pratique[END_REF]Portuguese Republic, 2009, for France and Portugal respectively).

Both in fuel breaks and area-wide treatments, there is a wide range of possibilities to maintain or promote lower fuel loads, including silvicultural techniques, agricultural and grazing management, or even the use of fire. These treatments will increase the opportunities for safe and successful fire suppression options and reduce the fire severity on the ecosystem or valuable assets (e.g. [START_REF] Rigolot | Managing wildfire risk: prevention, suppression[END_REF]. Several surface fuel management techniques are available including mechanical clearing (increasing fuel compactness), phytocides (limiting plant growth), prescribed burning and controlled grazing (reducing fuel load) [START_REF] Etienne | Combining techniques of fuel reduction for fuelbreak maintenance in the French Mediterranean region[END_REF][START_REF] Valette | Intégration des techniques de débroussaillement dans l'aménagement de défense de la forêt contre les incendies[END_REF][START_REF] Xanthopoulos | Forest Fuels Management in Europe[END_REF]. Trees have a role to play for reducing inside stand wind speed and for limiting under storey vegetation growth, and should be maintained, ensuring the appropriate disruption in the vertical and horizontal fuel continuity. Agricultural cultivations and other land uses can be included in fuel break networks as far as they provide a low flammability cover type during the fire season.

The spatial distribution of fuel treatments should better follow a strategic than a random pattern [START_REF] Fernandes | Scientific knowledge and operational tools to support prescribed burning: recent developments[END_REF][START_REF] Loureiro | A simulation-based test of a landscape fuel management project in the Marão range of northern Portugal[END_REF], and modelling approaches that have been used for optimizing prescribed burning planning can be used at the landscape scale (e.g. [START_REF] Loureiro | Optimizing prescribed burning to reduce wildfire propagation at the landscape scale[END_REF].

Knowledge gaps

Several controversial and relevant research topics in the fire-landscape relationships are still not known or totally clarified. We came across the following ones, while carrying out this review:

a) The role of humans in fire danger. On one hand, land abandonment increases fire hazard, due to fuel accumulation. But at the same time, given that humans account for most of the fire ignitions in the Mediterranean region (see for example [START_REF] Catry | Modelling and mapping wildfire ignition risk in Portugal[END_REF][START_REF] Moreno | Recent history of forest fires in Spain[END_REF], it could be hypothesised that a decline in population, and particularly farming activities, would reduce the number of fire ignitions. For instance, [START_REF] Koutsias | Do factors causing wildfires vary in space? Evidence from geographically weighted regression[END_REF] claim that demographic shifts from rural to urban areas may favour fuel conditions that lead to large fires, once a fire has been ignited. However, the same population reduction also reduces the probability of (human-caused) fire ignition, simply because less people are around to trigger a fire for whatever reason. Moreover, there is some anecdotal evidence that certain LULC types with low fire hazard can turned into very hazardous ones under improper management. For example, permanent crops such as olive groves and vineyards, which will act as fuel breaks under correct maintenance (periodical removal of grasses and weeds), can facilitate fire spread when not properly managed. On the other end, the increase in the extent of the wildland-urban interface might increase fire danger in areas surrounding villages and settlements. These topics should be clarified. b) Will climate change increase fire intensity? Climate change predictions point out an increase in fire risk, fire intensity, the length of fire seasons, the number of days in each season with extreme fire danger, and area burned per year (e.g. [START_REF] Moriondo | Potential impact of climate change on fire risk in the Mediterranean area[END_REF][START_REF] Pausas | Changes in fire and climate in the Eastern Iberian Peninsula (Mediterranean Basin)[END_REF]. But the detrimental effects of climate change on increased fire occurrence are not always obvious. In the Eastern Iberian Peninsula, [START_REF] Pausas | Changes in fire and climate in the Eastern Iberian Peninsula (Mediterranean Basin)[END_REF] found a positive correlation between summer rainfall and area burned two years later, suggesting that this rainfall increases fuel loads for the subsequent fire seasons. In this perspective, climate change could decrease fire hazard by constraining vegetation growth and biomass (fuel accumulation). This author concluded that more research is needed on the potential impact of lower but drier fuel loads on future fire regimes. c) Is fire size limited by weather or landscape pattern? There is still a debate on whether landscape pattern or meteorological conditions is the fundamental control of fire spread in Mediterranean landscapes. A better understanding of these processes has strong implications for landscape planning, and to the expected role LULC management has in reducing fire extent of fire damages. d) Does fire suppression policies increase large fire occurrence? Further research is needed on the impact of fire suppression policies on resulting fire sizes. If scientific research shows beyond doubt that fire suppression policies, if not accompanied by fuel management, lead to fuel accumulation and are responsible for large fire outbreaks, a major shift on resource allocation from suppression to prevention should be made.

e) The role of invasive exotic species in fire hazard. Scientific evidence also suggests that controlling the spread of invasive species in burned areas could decrease future fire hazard. Exotic invasive species are becoming a major problem in Europe [START_REF] Lambdon | Alien flora of Europe: species diversity, temporal trends, geographical patterns and research[END_REF] and in specific regions (e.g. Portugal) are one of the main concerns of forest managers in burned areas. Their role on fire regime and post-fire ecosystem responses need to be further evaluated.

  of final draft post-refeering, original publication available at http://www.sciencedirect.com -doi:10.1016/j.jenvman.2011.06.028

Acknowledgements

This study was carried out under the scope of COST Action FP0701 "Post-fire forest management in southern Europe" and the PHOENIX network of the European Forest Institute. Support from projects IFAP-IP "Recuperação de áreas ardidas", FIRELAND (FCT Project PTDC/AGR-CFL/104651/2008) and FIREREG (FCT Project PTDC/AGR-CFL/099420/2008) is also acknowledged.

Figure 1 Moreira F., Viedma O., Arianoutsou M., Curt T., Koutsias N., Rigolot E., Barbati A., Corona P., Vaz P., Xanthopoulos G., Mouillot F. and Bilgili E. (2011) Landscape -wildfire interactions in Southern Europe: implications for landscape management, Journal of Environmental Management, vol. 92, 2389-2402, Author-produced Moreira F., Viedma O., Arianoutsou M., Curt T., Koutsias N., Rigolot E., Barbati A., Corona P., Vaz P., Xanthopoulos G., Mouillot F. and Bilgili E. (2011) Landscape -wildfire interactions in Southern Europe: implications for landscape management, Journal of Environmental Management, vol. 92, 2389-2402, Author-produced version of final draft post-refeering, original publication available at http://www. sciencedirect.com -doi:10.1016/j.jenvman.2011.06.028