TABLE OF CONTENTS 1. Introduction

Prescribed burning (PB) is defined (e.g., [START_REF] Wade | A Guide for Prescribed Fire in Southern Forests[END_REF] as the use of fire in wildland vegetation under environmental conditions and using techniques allowing to satisfy predefined and properly formulated management objectives. The prescription defines the desired burn conditions as well as a set of operational procedures ensuring that fire is controlled in size, intensity and environmental impacts. PB combines art and science and is expected to comply with a planning and evaluation process that distinguishes it from traditional burning practices [START_REF] Pyne | Introduction to Wildland Fire[END_REF]. As a concept and practice, PB was originated and developed in the SE of the USA and in Australia in the 1930s-1960s. From a tool locally used in the frame of rural economy, fire became an institutionalized technology serving silvicultural, forest protection and ecosystem restoration goals.

This introduction focus solely on France and Portugal, where the practice is more institutionalized, even if it was in Greece in the 1960s that PB was first advocated and the first experiments were carried out [START_REF] Liacos | Present studies and history of burning in Greece[END_REF]. Early 19 th century descriptions reveal burning practices in maritime pine forest in southern France consistent with the concept of PB, obeying to legislation and generalized among landowners in the Maures and Esterel region [START_REF] Alexandrian | Feu contrôlé et contre-feu dans les Maures et l'Estérel en 1869[END_REF]. This memory was lost, and PB was introduced in France in the 1980s after a visit of French foresters to the USA. The initial demonstrations in pine forest were fostered by the contemporary Portuguese experience and were carried out 'a la portugaise' [START_REF] Binggeli | Dix ans de brûlage dirige dans les forêts du Massif des Maures[END_REF]. However, and given the initial lack of interest by forest managers, the first initiatives were limited to INRA's research and focused on PB ecological effects and comparison with the results attained with other fuel treatment methods. The first 'true' PB programs in France were established in open vegetation in the Eastern Pyrenees and Maritime Alps and subsequently expanded to other regions. PB appears in the French forestry law since 1992, which states that '… forest fire prevention activities carried out by land management collectivities can include PB in pastures and treeless areas …'. However, legislation considering PB in its full extent did not appear until 2001, even if it was preceded by the definition of formal training processes: burn crew leader, 12 days of training, 1996; and burn crew element, 5 days of training, 1998. Regulation of training activities was completed in 2004, which are located in two centers (Gardanne, Bouches-du-Rhône; Bazas, Gironde) and are monitored and assessed by a national committee. Additionally, burn credentiation requires significative operational experience.

PB is nowadays actively and officially supported by the Mediterranean French agencies and organizations involved in fire management. Wildfire hazard reduction has been the initial goal of PB in France, with proven benefits to wildfire control operations [START_REF] Rigolot | Etude sur la caractérisation des effects causés aux écosystèmes forestieres méditerranéens par les brulages dirigés et répétés, exercice[END_REF][START_REF] Lambert | Analyse aprés incendie de six coupures de combustible[END_REF]. However, as burn crews developed their capacity, additional objectives were added, namely habitat management for pastoral, hunting or nature conservation purposes. Burn crews are of variable origin -the forest service, protected areas, civil protection, pastoral associations -and their number increased gradually between the 1980s and the 2000s. The teams are organized in a network initiated under INRA's umbrella and periodically gather to share experiences.

Similarly to France, a description exists of a PB-like 19 th -century practice in pine forest in Portugal. Officially, PB in Portugal was introduced after visits by Edwin Komarek from the Tall Timbers Research Station in Florida in the 1970s. [START_REF] Silva | Fogo controlado[END_REF][START_REF] Silva | Historique des feux contrôlés au Portugal[END_REF] gives an historic account of the initiation and early development of PB in Portugal. The Forest Service trialled PB in the pine stands of NW Portugal between 1976 and 1981. An 'emergency plan' to reduce fire hazard followed in the winter of 1982, probably the first of its kind in southern Europe and respecting to ~55% of the communal forest area in the region. More than adopted, PB in NW Portugal was adapted to the local context, and its development paralleled that of research. Analysis of the data collected by the practitioners revealed significant insufficiencies in planning, but also effective hazard reduction without detrimental effects [START_REF] Fernandes | Analysis of the prescribed burning practice in the pine forest of northwestern Portugal[END_REF]. Roughly from 1994 to 2004 PB become an occasional and very localized practice. Increased political support as a consequence of the tragic fire seasons of 2003 and 2005 and improved and more widespread training lead to a recent revival of PB activity in Portugal, which has spread from the NW region to include other vegetation types.

Previous work has addressed the policies, legislative framework and practices of PB in southern Europe and how they have evolved [START_REF] Lázaro | Overview of prescribed burning policies and practices in Europe and other countries[END_REF][START_REF] Montiel | Best Practices of Fire Use -Prescribed Burning and Suppression Fire Programmes in Selected Case-Study Regions in Europe[END_REF], as well as the existing societal concerns and future perspectives and challenges [START_REF] Fernandes | Prescribed burning in southern Europe: developing fire management in a dynamic landscape[END_REF]). Here we supplement and update previous characterizations of PB in southern Europe with more detailed and thorough information, including data collected in the frame of the PB monitoring process.

Prescribed burning legal framework and regulation

The legal framework for PB in southern Europe is quite variable. In France the framework for the practice is given by the following legal documents: 1) and Italy (Table 2), PB-related legislation and regulation are regional in nature.

Characterizing prescribed burning

Our characterization of PB in southern Europe is restricted to its western sector, i.e. Portugal, Spain, France, and Italy, as PB is not practiced elsewhere. The elements available to characterise the practice vary widely across countries and regions. We could access the official Portuguese and Catalonian databases that report information for each individual burn operation, respectively maintained and made available by the ICNF (Forest Service) for the 2006-2015 period, and collected (for the period of 1998 to 2015) from the Generalitat de Catalunya Bombers website (https://bombers.blog.gencat.cat/2016/01/07/informacio-cremes-prescrites-bombers-1998-2015/). For the remaining regions of Spain we rely on information supplied by regional agencies. Regarding France we used preprocessed and summarized data (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) from the database maintained by INRA. Finally, Italian data were supplied by Davide Ascoli (University of Torino) and Giuseppe Delogu (CFVA, Sardegna). Hence, it is not easy to harmonize analysis and compare PB across southern Europe countries.

Prescribed burning objectives

PB objectives in southern Europe are variable, but fuel hazard reduction and pastoral burning are prevalent. Fuel reduction to decrease fire hazard is particularly (and overwhelmingly) important in Portugal (Table 3). Equilibrium exists between hazard reduction, essentially by treating specific locations in a strategic location, and pastoral/habitat management in Catalonia, while land management objectives other than hazard reduction prevail in France.

Regional distinctive patterns regarding PB objectives are quite manifest in Spain. Catalonia depicts the most balanced and complete set of objectives (Table 3). In the northern regions of the country (Galicia, Asturias, Cantabria, Navarra, Aragón) and in Extremadura, PB is used solely to manage pastures and shrublands for grazing, which simultaneously decreases the risks of unplanned damaging fires. In contrast, grazing is not mentioned as a PB motive in Castilla-La-Mancha and Andalusia, and fuel hazard reduction either (or both) in wildlands and wildland-urban interfaces and training emerge in the former two regions and in Valencia and Castilla y León, besides Catalonia. Four types of PB uses occur in Italy in the four regions where it is practiced: fuel hazard reduction, rangeland management, training, and habitat restoration, all of them present in Campania and Piemonte. Sardegna and Toscania employ PB respectively for the first three and for the first two objectives.

Prescribed burning activity in numbers

Extent and location

PB activity in southern Europe remains local in scope and the area treated is quite modest (Figure 1). The number of burn operations in Portugal exceeds Catalonia by a factor of four, and is exceeded by a factor of three in France. The leading position of France is confirmed by the amount of area treated, which is four times higher than in Portugal.

Despite annual variation no temporal patterns in the extent of PB activity are visible in Figure 1. The total amount of prescribed-burnt area in Spain is not available -but see [START_REF] Lázaro | Development of prescribed burning and suppression fire in Europe[END_REF] Larger figures respect to regions, smaller (italic) figures respect to departments that contributed with a minimum of 0.5% to total area treated and could be individualized. In France, PB activity is concentrated in the south of the country in Provence-Alpes-Côte d'Azur, Languedoc-Roussillon Midi-Pyrénées and Corsica NUT2 regions, which together account for 93% of the treated area (Figure 2). Two departments are particularly relevant for PB in France, as they concentrate more than half of PB area, respectively the Maritime Alpes (31.0%) and Eastern Pyrenees (20.4%); in the latter case 14% of the total rangeland area has been treated with PB from 1987 to 2009 [START_REF] Lambert | The French prescribed burning network and its professional team in Pyrénées Orientales: lessons drawn from 20 years of experience[END_REF]. Quantitative assessment of PB extent is more limited in some regions (e.g. Pyrenees) by the new tendency of PB teams to support traditional burning practices (training) and to limit their own activity to the most difficult PB operations [START_REF] Fernandes | Prescribed burning in southern Europe: developing fire management in a dynamic landscape[END_REF]. In Portugal most PB operations are carried out in the north of the country, and especially in the oceanic NW quadrant (55% of total area treated, Figure 3), being essentially absent from the south of the country.

Size and vegetation/fuel types

PB operations are small in the Mediterranean basin. Roughly half of the burns belong to the 1-4 ha size class, both in Portugal and in Catalonia (Figure 4), and only 10% of the burns exceed 20 ha (Portugal) and 10 ha (Catalonia). The results of inquiries to fire managers indicate that in other Spanish autonomies PB units do not exceed 5 ha (Valencia, Aragón, Andalusia, Castilla-La-Mancha), 10 ha (Galicia, Asturias, Cantabria), 20 ha (Navarra), or 30 ha (Castilla y León). Likewise, figures for Italy are <5 ha (Piemonte, Toscana) and <10 ha (Campania, Sardegna). By way of comparison, mean PB size in USA federal land is 34.5 ha [START_REF] Barnett | Beyond fuel treatment effectiveness: Characterizing Interactions between fire and treatments in the US[END_REF]. Burn operations increase in size from Catalonia to Portugal and from Portugal to France, and those carried out in shrubland and grassland double in size in relation to forest PB (Table 4). In France, annual mean PB size decreased almost by half from 2001 to 2016 ha, reaching about 10 ha (n=4870 PB operations) which is viewed as a refinement of PB implementation. PB in forest requires more personnel because the need to maintain fire intensity and effects on trees within acceptable limits imply more conservative ignition patterns. A breakdown of data by fuel type (Table 5) does not detract from the trend, but it is interesting to note that in Portugal the mean size of PB is comparable in shrubland, pine forest without understory (hence lower potential fire intensity), and post-harvest slash fuels. (PT, 2006(PT, -2015) ) and Catalonia (CAT, 1998(CAT, -2015)). Maximum PB sizes in the databases are 146 ha (PT) and 67 ha (CT). For the Eastern Pyrenees in France a maximum of 179 ha is mentioned by Lambert (2010).

Seasonality

PB operations in Portugal are carried out essentially from October to May, and mostly in the February-April period (Figure 5). In Catalonia PB can proceed at any month of the year, but the number of operations and area treated are strongly concentrated in February-March. For the rest of Spain PB is an Autumn to Spring activity, except in Andalusia where it is practiced only during Spring. PB operations in France occur during Winter and Spring, but in Alpes Maritimes, Haute-Garonne, Pyrénées Orientales, Corse and Landes de Gascogne also include the Autumn months. Finally, Italian PB proceeds from Autumn to Spring, except in Piemont (Autumn-Winter).

Figure 5. Monthly distribution of PB operations and treated area and monthly mean PB size in Portugal (PT, 2006(PT, -2015) ) and Catalonia (CAT, 1998(CAT, -2015)). PB-FR-66

Spatial patterns

The spatial features of PB are a relevant descriptor, as they indicate how the practice impacts landscape structure and the potential for large fire spread. The small scale of PB in Europe, in both treatment size and treatment effort, implies that most PB units are dispersed in the landscape and account for a small fraction of the potentially treatable area. However, at sub-regional to local scales the landscape imprint of PB history is visible. Such is the case of the Eastern Pyrenees in southern France where PB is mostly used to maintain or restore rangelands (Figure 6). Long-term (since 1983) mapping of PB areas produced a small-grained mosaic of vegetation patches, which is generally viewed as beneficial for both wildfire hazard reduction and biodiversity [START_REF] Lambert | The French prescribed burning network and its professional team in Pyrénées Orientales: lessons drawn from 20 years of experience[END_REF].

In Catalonia, 45% of the total number of PB are designed as 'strategic management points', i.e. PB is applied to specific locations that are expected to block or delay the spread of a subsequent wildfire. Most patches shown in Figure 7 reflect this strategy. In Portugal, PB units tend to be more linear in shrubland, corresponding to fuel breaks (up to 200-m wide), and are more variable in shape in forests (Figure 8). Overall, the effect on the spread of a large wildfire is expected to be minimal, because PB projects are very localized and the blocking/delaying effect of treatments is seldom replicated or supplemented by nearby treatments [START_REF] Finney | A computational method for optimising fuel treatment locations[END_REF]).

Prescribed burning management

PB management, as naturally expected, varies widely across Europe. PB managers can resort to a variety of tools to help in the decision-making process of where, when and how to burn. In particular, plot/stand or landscape-level fire behaviour simulators, including either those developed by the USDA Forest Service (based on Rothermel's fire spread model and assignment of fuel models to typify fuel conditions) [START_REF] Finney | An overview of FlamMap fire modeling capabilities[END_REF][START_REF] Andrews | Current status and future needs of the BehavePlus Fire Modeling System[END_REF] or empirically-based burning guides such as PiroPinus [START_REF] Fernandes | PiroPinus: a spreadsheet application to guide prescribed burning operations in maritime pine forest[END_REF]). In the Spanish regions of Valencia, Andalusia, Catalonia and Castilla-La-Mancha PB planning makes use of fire behaviour modelling tools, and training on the use of such tools is standard in Portugal. However, more often than not, PB users define their prescriptions from generic burning windows as a function of monitored weather and fuel moisture conditions, e.g. PB planning in France does not rely on fire behaviour simulation. A set of burn prescriptions for European ecosystems has been previously developed (Fernandes and Loureiro 2010;Fernandes et al. 2010), based on the analysis and compilation of existing burning guides and best practices, prescriptions from the agencies and individuals involved in PB management or research in Europe and, additionally, usage of fire behaviour and effects models to assist in attaining specific treatment goals. Likewise, fire-modeling based spatial-planning of PB is customary in Catalonia, but does not seem to be practiced elsewhere, with the exception of a few Portuguese examples (Figure 9). An important component of PB management is the ability to attain treatment area targets. In this respect, it is crucial that burning opportunities (as defined by the weather prescription) are fully exploited, which can be achieved through close monitoring of weather forecasts and fire danger rating (e.g., Figure 10) combined with flexibility, i.e. PB is given top priority.

Figure 9. Spatial planning of PB units (in yellow) as part of a Forest Service fuel treatment project implemented in central Portugal (Perímetro Florestal do Rabadão, Góis). Results of simulations with the FlamMap software contributed to the decision-making process, allowing to identify major fire travel routes (blue lines) using a minimum travel time algorithm [START_REF] Finney | A computational method for optimising fuel treatment locations[END_REF]) and optimal treatment locations as a function of wind direction scenarios (pink, red and dark brown areas). Map supplied by P. Palheiro. (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) are illustrative of the existing difficulties:

-The estimated number of annual burn days for each PB 'cell', based on normal climatology, varies between 20 and 83, but on average and since 2001, PB operations only took place on 58% of that number of days (range: 13-121%);

-the total number of calendar burn-days per year (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) varied in the 40-91 range, mean = 66;

-the average annual number of burn-days per 'cell' varied between 7 and 18, averaging 10 (2001-2015);

-only half of the planned PB area was achieved, with an yearly variation ranging between 33.5 and 72.4%.

A properly managed PB programme should also include post-treatment evaluation of results and long-term monitoring, in order to correct deficiencies, improve the practice, and consequently ensure social acceptance. In Portugal, PB reporting includes an assessment of whether treatment objectives were met and to what extent. For the 2006-2015 period, respondents classified the accomplishment of objectives as 38.8% very good, 53.9% good, 6.3% acceptable, 0.7% unsatisfactory, and 0.2% very unsatisfactory. This is a more optimistic assessment than previous work [START_REF] Fernandes | Analysis of the prescribed burning practice in the pine forest of northwestern Portugal[END_REF]) revealed for the 1980s-1990s, which can reflect improved procedures but probably is biased because it was not carried out independently. In fact, preliminary inspection of the database suggests that ~50% of the PB were carried out under sub-optimal to excessively dry fuel conditions. Comparative data for other countries was not available.

The quantification of PB costs is an important component of its evaluation. In France, an important cost factor is whether the PB is a first entry or maintenance operation, the former being more costly. Annual means for regional averages (2009)(2010)(2011)(2012)(2013)(2014)(2015) varied from 139 to 288 € ha -1 , with ranges of 29-135 and 764-1241 € ha -1 for the minimum and maximum costs, respectively. Portuguese surrogate data for costs (personnel and equipment used) offer some insight on what drives PB costs. The amount of human resources and vehicles used in the operations is poorly correlated with PB size (Figure 11). This implies that increasingly larger PB units will be increasingly less costly to treat. Indeed, personnel costs per unit area treated decrease sharply when PB size exceeds 2 ha and stabilize in its minimum at ~5-10 ha. Hence, these thresholds are useful to rationalize PB costs and offer an additional argument to increase the spatial scale of PB. The evaluation of PB costs in Spain (Rodríguez Silva 2016 personal communication available online [https://www.youtube.com/watch?v=FRfgukRYdBU] based on González-Pan 2012b) shows average values from 650 to 890 € ha -1 . Most of costs are human resources (72%) and the rest are materials and indirect costs (28%). The preparation of PB consumes 41% of the total cost (shrub cutting and removal), followed by fireline ignition costs (36%) and by extinction costs (23%). PB size (ha)

Conclusions

Proper, 'complete' legal and regulamentory frameworks for PB exist in France and Portugal only, mirroring the current state of development and acceptance of PB in southern Europe. The predominant motives for PB vary between and within countries. Rangeland management prevails in northern Spain autonomous regions and in France, where PB is largely a surrogate for traditional burning practices that are declining or are perceived as risky (given the current trends in fuel accumulation and landscape-scale fuel connectivity) or unsustainable. In Portugal, where the wildfire problem is distinctively more severe, and in the Spanish regions that confine with the Mediterranean, hazard reduction takes the lead although rangeland management can still be relevant.

The degree of PB implementation remains quite limited, as shown by the size and, especially, the extent of areas treated. However, PB is a relevant practice at sub-regional to local scales -in the Maritime Alps and Eastern Pyrenees in France and in NW Portugal -where it leaves its mark in the landscape and is a significant factor in the fire regime; note that in France PB extent is sometimes larger than wildfire extent. PB has attracted increasing interest in Portugal and Spain during the current decade but so far that did not translate into more area treated. Obstacles to PB expansion are varied and important, including social acceptance, funding, training and available human resources, administrative constraints and difficulties to accept PB in the forest services, land tenure and conservation status, weather/climate constrains, and existing or potential conflicts with other land management activities and assets. Furthermore, a substantial increase in PB area is unlikely as long as fire management policies are reactive and dominated by activities in the realm of pre-suppression and suppression.

Open vegetation types (shrubland and grassland) are the main PB target in southern Europe, with the exception of Catalonia. This relates with treatment objectives, i.e. management for grazing or for other purposes that require the maintenance of initial seral states, but has also to do with the existence of stronger obstacles to apply fire in forests. And yet, in fire prone regions where hazard reduction is an important concern, PB in forests is expected to be more effective than in shrubland, and forests are in general a more valued asset. Where PB effort is large enough to create a fuel-age mosaic, wildfire spread should be substantially constrained, but otherwise current spatial patterns of PB in Europe do not seem to be effective at impacting large-fire growth. In face of the existing limitations to apply PB on a broader scale, the Catalonian practice of treating 'strategic points' is suggestive of a low cost-to-benefit ratio but this warrants further research.

Current management of PB operations, from planning to evaluation and monitoring is also quite heterogeneous. PB management procedures in Europe seem poor in comparison with overseas practices carried out by relatively large organizations that manage fire on public land and on much broad scales. The need for better PB management will only arise if the practice expands, but further progress is desirable under the current situation. Room for improvement is apparent concerning spatial planning, burning opportunities, compliance with burn prescriptions, and optimization of costs. All of these would be benefited by increased use of decision-support tools.

Figure 1 .Figure 2 .

 12 Figure 1. Temporal evolution of the total area and number of PB operations in Portugal (PT), Catalonia (CAT), and France (FR). Overlaid values are means for 2006-2015, for which data was available for comparison.

Figure 3 .

 3 Figure 3. PB area distribution (%) in Portugal (2006-2015).

Figure 4 .

 4 Figure 4. Distribution of PB operations by size class and cumulative probability of PB size in Portugal(PT, 2006(PT, -2015) ) and Catalonia(CAT, 1998(CAT, -2015)). Maximum PB sizes in the databases are 146 ha (PT) and 67 ha (CT). For the Eastern Pyrenees in France a maximum of 179 ha is mentioned by[START_REF] Lambert | The French prescribed burning network and its professional team in Pyrénées Orientales: lessons drawn from 20 years of experience[END_REF].

Figure 6 .

 6 Figure 6. PB spatial patterns in the Eastern Pyrenees department of France (1983-2016), including the burn mosaic detail for the largest area treated. Map supplied by B. Lambert.

Figure 7 .

 7 Figure 7. Examples of spatial patterns of PB in Catalonia, overlaid on Google Earth imagery. Data source: https://bombers.blog.gencat.cat/2016/01/07/informacio-cremes-prescrites-bombers-1998-2015/

Figure 8b .

 8b Figure 8b. Examples of spatial patterns of PB in Portugal, overlaid on Google Earth imagery. Data source: ICNF.

  PB planning occurs on an annual (France, Spain, Italy) to multi-annual (Portugal) scale. France and Portugal have implemented systems to collect PB data and monitor practitioners' activity, respectively through the National PB network initiated by INRA and ICNF. Differently from Spain, where PB implementation is limited to state organizations (either forest services or civil protection agencies, most noticeably EPRIF in northern Spain and Extremadura), PB users in France and Portugal have more diverse backgrounds, including private forest associations, pastoral associations, and municipalities. Still, the amount of active teams is limited in both countries. In France, an average of 20 PB 'cells', i.e. teams with active PB activity, was recorded between2001 and 2015. In Portugal (2006-2015), 86 different technicians participated in PB operations, but only 24 were involved in more than 20 fires. These figures explain in part the modest acreage of PB in southern Europe.

Figure 11 .

 11 Figure 11. Size of individual PB operations in Portugal (2006-2015) plotted and regressed (linear least squares fit) as a function of number of operational personnel and number of fire-fighting vehicles employed.

Figure 12 .

 12 Figure 12. Number of operational personnel, normalized by area, plotted as a function of the size of individual PB operations in Portugal (2006-2015). The inset enlarges the lower ranges of variation to better show the 5-10 ha threshold above which persons ha -1 stabilizes. PB carried out for training or scientific purposes are excluded.

-

  Loi d'orientation forestière, July 9 2001 (L 321-12 du C.F.) -Forest defense against fires decree, April 29, 2002; -Interministerial decree of 15 March 2004 on the validation of the competences of those responsible for PB and

	incineration;
	-Circular DERF/SDF/C2002-3021 of 31 October 2002 on the protection of forests against fire: prescribed burning and
	incineration;
	-Circular DGFAR/SDFB/C2004-5033 of 31 August 2004 on the training and validation of the competences of persons
	responsible for PB and/or incineration;
	-Law no. 2010-874 of 27 July 2010 of modernization of agriculture and fisheries, article 69.
	Additionally, PB in France is subjected to Local Arrêté départemental regulation.
	In Portugal, PB use (and in general the use of 'technical' fire) is regulated by Despacho no. 7511/2014 from 9 June
	2014, which abides by Decree-Law no. 124/2006, of June 28 (National System of Forest Defense Against Wildfires)
	with subsequent modifications (no. 15/2009 and 17/2009, of January 14, 114/2011, of November 30, and 83/2014, of
	May 23). In Spain (Table

Table 1 .

 1 Legal framework and PB regulation in Spain.

	Autonomous region	Legal framework	Specific PB regulation
			Annual decisions about PB permits, e.g. Decreto
			105/2006 de 22 de junio por el que se regulan
	Galicia	Ley 3/2007 de Prevención y Defensa contra los incendios forestales en Galicia	medidas relativas a prevención de incendios forestales, la protección de los asentamientos en el medio rural y la regulación de
			aprovechamientos y repoblaciones forestales
			Annual decisions about PB permits, e.g.
			Resolución de 30 de enero de 2012 de la
	Asturias	Ley 3/2004 de Montes y Ordenación Forestal	Consejería de Agroganadería y Recursos
			Autóctonos por la que se aprueban las normas
			sobre quemas en el territorio del Principado de
			Asturias
	Cantabria	Orden DES/44/2007 Normas de uso del fuego	Regulated for agricultural, grazing and
			silvicultural uses
			Annual decisions about PB permits and
	Navarra

regulation about the use of fire in pasture regeneration and silviculture, e.g. Orden Foral 231/2011 de 15 de noviembre de la Consejería de Desarrollo Rural por al que se regula el régimen excepcional de concesión de autorizaciones para el uso del fuego como el tratamiento de los pastos naturales y realización de trabajos selvícolas Castilla y León Ley 3/2009 de Montes de Castilla y León Annual regulation on fire risk season and restrictions to fire use Valencia Ley 3/1993 Forestal de la Comunidad Valenciana Annual regulation on fire risk season and restrictions to fire use, e.g. Orden de 30 de marzo de 1994 de la Consellería de Medio Ambiente por las que se regulan las medidas generales para la prevención de incendios forestales Extremadura INFOEX Plan Annual regulation on fire risk season and restrictions to fire use Aragón Orden anual de Prevención y Lucha contra incendios Annual regulation on fire risk season and restrictions to fire use Andalusia Ley 5/1999 de Montes de Andalucía and INFOCA Plan Annual regulation on fire risk season and restrictions to fire use Catalonia Decret 312/2006, de 25 de juliol, pel qual es regula la gestió del foc tècnic per part del personal dels serveis de prevenció i extinció d'incendis de la Generalitat de Catalunya Regulated for agricultural, grazing and silvicultural uses Castilla-La Mancha Orden 26/09/2012 de la Consejería de Agricultura (DOCM de 1 de octubre de 2012) Capacity and authorization of forest firefighting crews to plan and carry out PB Canarias Decreto 146/2001 por el que se regula la prevención y extinción de incendios forestales n.a.

Table 2 .

 2 Legal framework and PB regulation in Italy.

	Administrative region	Legal framework	Specific PB regulation
	Campania	n.a.
	Sardegna	Regional Fire Management Plan 2014-2016 -	n.a.
		Delibera n. 33/22 of 10/06/2016
	Toscana	n.a.	Decreto Giunta Regionale 48/2003. Regolamento
			Forestale della Toscana di attuazione della LR n. 39
			del 21/03/2000. Aggiornato con decreto del Presidente
			della Giunta regionale 16 marzo 2010, n. 32/R.

Legge regionale 13 giugno 2016, n. 20. Norme per l'applicazione pianificata del fuoco prescritto. Piemonte n.a. Legge Regionale n. 21 del 2013. Norme di attuazione della legge 353/2000.

Table 3 .

 3 Prescribed fire operations distribution (number / area, %) in Portugal and Catalonia by treatment objective.

	Objective	Portugal (2006-2015)	Catalonia (1998-2015)	France*
			Strategic fuel treatment 45.1 / 25.1
	Fuel treatment	81.2 / 84.0	Civil protection	10.3 / 7.6	33.0 / -
			Silviculture	10.9 / 6.4
	Silviculture	4.0 / 4.0 a		-	18.7 / -c
	Pastoral	6.1 / 9.5		20.4 / 46.8	41.3 / -
	Habitat management b	1.5 / 0.7		2.0 / 5.4	7.0 / -
	Training	5.1 / 1.8		8.4 / 7.7	-
	Research	2.1 / 0.1		2.5 / 1.2	-

a Mostly slash burning after tree harvesting in eucalypt plantations. b Wildlife management (including for hunting), nature conservation. c Includes burning for agricultural purposes and with other objectives. * Averages for the years

2002, 2007 and 2014.

  and González-Pan (2012a), who indicate 6910 ha (pasture and shrubland) treated by EPRIF (Integral Wildland Fire Prevention Teams) from 2003 to 2008, and 6260 ha treated from 2009 to 2012 (1182 ha in 2010, 2226 ha in 2011 and 1693 ha in 2012) -or for Italy, where the practice still is essentially experimental[START_REF] Ascoli | Prescribed burning in Italy: issues, advances and challenges[END_REF]; in Sardegna, annual PB area averages 50 ha (G. Delogu, personal communication). Overall and on average, we estimate a ~7000-ha annual PB area in southern Europe.

Table 4 .

 4 PB operations in forest as a percentage of the total and PB size in forest versus open vegetation types. a minor component of total PB activity in Portugal and France, especially in area, in contrast with Catalonia (Table4). While forest underburning has never been a relevant component of PB in France, current figures for Portugal are in stark contrast with the earlier (1980s-1990s) practice, which was essentially focused on maritime pine (Pinus pinaster) stands[START_REF] Fernandes | Analysis of the prescribed burning practice in the pine forest of northwestern Portugal[END_REF]. Although forest underburning represents only 5% of the total treated area in France during the six last PB seasons, its cumulative value however reaches a total of 1149 ha.

		Portugal	Catalonia	France
	Number	14.5	63.0	9.4
	Area	9.3	40.5	4.5
	Mean size (ha)
	Forest	4.93	2.13	5.23
	Open types	8.20	5.35	11.54
	PB underburning is

Table 5 .

 5 PB operations distribution in number and area (%) by fuel type.

	Fuel type	Portugal		Catalonia
		No. / Area	Mean size (ha)	No. / Area	Mean size (ha)
	Grass	0.5 / 0.1	1.27	6.0 / 13.0	7.17
	Shrub	78.2 / 83.8	8.48	26.3 / 41.0	5.19
	*Grass-Litter	-	-	15.2 / 10.3	2.25
	*Shrub-Litter	9.0 / 3.7	3.59	37.9 / 23.9	2.09
	*Litter	5.4 / 5.6	9.18	-	-
	*Slash	7.0 / 6.8	7.56	9.7 / 6.3	2.15
	Stubble	-	-	4.7 / 5.5	3.92

* Forest fuel types

ACKNOWLEDGMENTS

We thank Davide Ascoli, Bernard Lambert, Pedro Palheiro, Giuseppe Delogu, Jean-Luc Dupuy and Domingo Molina for the information provided or comments. The Portuguese Forest Service supplied its PB database. Grey literature from Spanish Autonomous regions are gathered thank to Raúl Quílez (Valencia), Juan Ramón Molina (Andalusia), José Almodóvar (Castilla-La Mancha) and Federico Grillo (Canary Islands).


Frederic Revers

Marie-Lise Benot

Didier Alard

David Rosebery

Marie Barneix

Biodiversity indicators based on several taxons help identify the range of pressures on coastal dunes

niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Loss of biodiversity is growing up and it is urgent to get tools to evaluate biodiversity state from local to global scales in order to better assess this phenomenon. One of these tools is the development of indicators, based on ecological and environmental metrics, which have to reflect biodiversity state as a whole. The good representativeness of indicators is still on debate among scientists as many contradictory results have been published on the robustness of species-based versus environmentalbased indicators or on the congruence of multi-taxon approaches. The present study addresses the question of biodiversity assessment along the 230 km-long Aquitaine coastal dunes, an area of great ecological interest but threatened by natural and anthropic factors. Our aim is to produce indicators allowing a good estimate of the dune conservation state. As a first approach, we have undertaken a breeding bird census along the coastal dunes in order to identify hotspot of bird diversity and explanatory environmental factors of bird assemblages. Results were confronted with plant surveys which have been performed for almost two decades. Birds and plants reflect the typical internal gradient of coastal dune from the foredune to the forest fringe. However, bird species composition are also explained by landscape variables including shrubs or urban area cover, while a north-south environmental gradient along the coastal dunes represents a major gradient explaining plant composition. The scope of this study on the assessment of the conservation state of the dunes will be discussed.

Univ Bordeaux, INRA, BIOGECO 1202, Allée Geoffroy Saint-Hilaire, 33615 Pessac Cedex

ONF, Agence LNA, 9 rue Manaud,

Bruges Cedex


Alain Roques

Jérôme Rousselet

Christelle Robinet

Pine processionary moth, Thaumetopoea pityoccampa (Lepidoptera: Notodontidae)

niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Native of the Mediterranean basin, pine processionary moth (Thaumetopoea pityocampa) is expanding its range northwards because of warmer winter temperatures increasing larval survival. Although it is a major forest pest with irritant larvae, moth knowledge remained scattered between countries and disciplines. Combining all knowledge and developing adapted management strategies has become an important challenge since the IPCC considers the moth as one of the few insects for which causal relationships between climate change and range expansion were demonstrated.

European and French projects developed since 2000 have taken a multidisciplinary approach, incorporating entomology, medical, and veterinary science, to study the natural history, genetics, impact on all organisms (tree, insect biodiversity, humans, and animals), risk modelling, and management of this pest.

We mapped the present insect range at the European scale as a baseline for assessing precisely its future expansion. Models revealed that most of western and central Europe is already favorable to establishment but colonized at only ca. 5 km/year due to the limited flight capabilities of females. However, convergent genetic and ecological studies showed that isolated colonies observed beyond the front edge mainly result from long-distance jumps related to the trade of mature ornamental trees or pupae being moved with the accompanying soil. Isolated pine trees in semi-urban areas (artificial heated-islands) act as corridors to facilitating expansion. This species is thus turning into an urban sanitary threat and health concerns associated with this invasion led to proposed new management tools based on a 'slow the spread' strategy.

doi: 10.1603/ICE.2016.92727

Authors


Mathieu Laparie

Christelle Robinet

Jérôme Rousselet

Alain Roques

The range expansion of the pine processionary moth in a changing world: How a well understood multifactorial process could tangle up

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

1829: The range expansion of the pine processionary moth in a changing world: How a well understood multifactorial process could tangle up Tuesday, September 27, 2016 02:15 PM -02:30 PM Introduction: While distributional changes associated with climate change have been widely acknowledged in ectotherms in the light of their ecophysiological limits, causal relationships with range shifts have still rarely been demonstrated. In the pine processionary moth, a winter-developing insect, combined experimental and modelling evidence have elucidated the mechanisms in which average winter warming has lowered barriers to expansion. Nonetheless, warming may also alter life cycles, or vulnerable instars may be subjected to new stressors associated with climate fluctuations. Comprehensive responses to such varied conditions are not fully untangled yet, and the spread may be more complex than initially thought due to mixed effects of future climate change, its spatial dependency, and population differentiations.

Methods: This presentation will be based upon published work on this study system, spanning a number of techniques ranging from thermal biology under controlled conditions and semi-natural experiments to field surveys and in silico approaches.

Results/Conclusion: Tolerance to acute cold is considered high enough to withstand usual minimal temperatures near front edges, but larval susceptibility to cumulative chill injury and thermal induction of foraging were evidenced. Both processes impair colony survival of this gregarious species under natural conditions. Spread simulations from climate records and feeding thresholds showed that warmer winters have opened previously unsuitable areas that match those actually neo-colonized. However, thermal constraints depend on genotypes and life stages, which have yet to be considered. Demographic outcomes of climate variations are thus contingent on geography and phenology, the latter being known to vary among populations.

doi: 10.1603/ICE.2016.93550

Authors