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Key messageFire activity has decreased in the last decades in Spain as a whole and in most provinces. However, fire riskfactors have increased. Wildfires are burning preferentially treeless areas. Flammable pine areas burn less, while the lessflammable oak forests burn more. This decreasing fire activity coincides with increasing fire suppression resources. - ContextClimate and other fire risk factors are changing across the world, including the Mediterranean region. It is important todetermine how fire activity is responding to such changes. - AimsTo identify spatio-temporal changes in fire frequency and size, main tree species burned, and their association withchanges in climate, land-use and land-cover, and fire suppression. - MethodsAnalysis of trends, breakpoints, and association among the time series of fire variables and fire risk factors during1980–2013 in Spain at country and provincial levels. - ResultsWildfires in Spain have been decreasing in number, burned area, mean, and largest fire sizes. Fires are more frequentlyburning treeless areas than forests. Pine forests are burning less, while oak forests are burning more. Fire suppression resources,particularly aerial ones, increased significantly. Risk factors like the mean summer fire weather index, and the forested and theartificial areas all increased. - ConclusionDespite increasing fire risk factors, wildfires have decreased at the country as a whole and in most provinces inSpain during the last 34 years

Climate has a strong influence on fire activity, varying across time and space. We analyzed the relationships between fire-weather conditions during the main fire season and antecedent water-balance conditions and fires in two Mediterranean-type regions with contrasted management histories: five southern countries of the European Union (EUMED)(all fires); the Pacific western coast of the USA (California and Oregon, PWUSA)(national forest fires). Total number of fires (≥1 ha), number of large fires (≥100 ha) and area burned were related to mean seasonal fire weather index (FWI), number of days over the 90th percentile of the FWI, and to the standardized precipitation-evapotranspiration index (SPEI) from the preceding 3 (spring) or 8 (autumn through spring) months. Calculations were made at three spatial aggregations in each area, and models related first-difference (year-to-year change) of fires and FWI/climate variables to minimize autocorrelation. An increase in mean seasonal FWI resulted in increases in the three fire variables across spatial scales in both regions. SPEI contributed little to explain fires, with few exceptions. Negative water-balance (dry) conditions from autumn through spring (SPEI8) were generally more important than positive conditions (moist) in spring (SPEI3), both of which contributed positively to fires. The R of the models generally improved with increasing area of aggregation. For total number of fires and area burned, the R of the models tended to decrease with increasing mean seasonal FWI. Thus, fires were more susceptible to change with climate variability in areas with less amenable conditions for fires (lower FWI) than in areas with higher mean FWI values. The relationships were similar in both regions, albeit weaker in PWUSA, probably due to the wider latitudinal gradient covered in PWUSA than in EUMED. The large variance explained by some of the models indicates that large-scale seasonal forecast could help anticipating fire activity in the investigated areas., This research was funded by the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement 243888 (FUME Project). Publication in Open Access was funded by the EC FP7 Post-Grant Access Pilot.

Durante la última década se ha evidenciado que además de los factores tradicionalmente considerados en ecología -recursos, condiciones e interacciones bióticas y abióticas-, la naturaleza espacial de los ecosistemas condiciona muchos de los patrones y dinámicas de los sistemas ecológicos. La inclusión del espacio en los modelos ecológicos ofrece nuevas perspectivas para explicar dichos patrones y ofrece un punto de encuentro entre numerosos procesos ecológicos. En este trabajo se clarifica el concepto de dependencia espacial en los modelos ecológicos dinámicos, ilustrándose su importancia para algunos casos específicos del ámbito mediterráneo. Igualmente se introducen algunos modelos ecológicos espaciales que han sido clave para el desarrollo de la ecología actual. Over the last decade it has been increasingly recognized that, in addition to factors traditionally considered in ecology -resources, conditions, biotic and abiotic interactions-, spatial processes play a critical role in explaining observed ecological patterns. The incorporation of space in ecological models brings new perspectives to explain these patterns, offering a meeting point for the understanding of many ecological processes. In this paper we clarify the concept of spatial dependence in dynamic ecological models, which is often a matter of confusion, and we illustrate this with specific examples from Mediterranean-type ecosystems. We also introduce spatial ecological models that have been critical for the development of current ecology. El presente trabajo ha sido financiado por los proyectos CAM-UAH2005/2004, REN2000-745 (CICYT) y CGL2005-05830-C03-01/ BOS (CICYT).

1. Resultados clave 1. Los incendios resultan de interacciones entre el clima y otros motores socioeconómicos que afectan al territorio. Todos cuentan, y todos han de ser tenidos en consideración al evaluar el futuro riesgo de incendio. 2. Los incendios se reparten por todo el territorio. Gestionar y conservar los ecosistemas terrestres españoles no puede ignorar el papel del fuego. La gestión debe ir más allá que la mera prevención, e integrar el conocimiento de la ecología de los ecosistemas en relación con el fuego. 3. El clima futuro y otros cambios socioeconómicos y globales ocasionarán situaciones extremadamente adversas, que se extenderán por más zonas del país de manera simultánea y con mayor frecuencia. 4. La planificación futura del riesgo no puede hacerse usando solo el pasado. Hasta mediados de este siglo, el cambio climático esperable es poco variable, con lo que las proyecciones futuras pueden usarse como marco de cálculo del peligro futuro. 5. Hay que gestionar el territorio con objetivos diferenciados de los bienes y servicios que se pretenden proteger, incluyendo la disminución de la peligrosidad del territorio, así como de las pérdidas y costes, al tiempo que se mantiene o aumenta la prestación de los servicios y su resiliencia. 6. El fuego puede tener cabida en una planificación por objetivos, aunque solo sea para reducir gastos, pues no será posible detener todos los incendios en los plazos establecidos en los programas de gestión y lucha contra el fuego. 7. Los incendios no se distribuyen homogéneamente, sino que hay zonas particularmente peligrosas. Hay que planificar minimizando el riego a la población, con especial consideración a la interfaz urbano-forestal. 8. Anticiparse al riesgo y a los impactos requiere conocer las vulnerabilidades y muchas de éstas están muy ligadas a la recurrencia de incendios. Se necesitan bases de incendios espacialmente explícitas para poder anticiparse a los impactos más indeseados.

Resumen de Tesis Doctoral. Departamento de Ecología de la Universidad de Alcalá, e Instituto de Recursos Naturales y Agrobiología (IRNA), CSIC, Sevilla. Junio de 2008. Dirección: Miguel Ángel de Zavala y Teodoro Marañón. Financiado por los proyectos HETEROMED (REN2002-04041) y DINAMED (CGL2005–05830).