j.g. pausas' blog

¿Por qué se dan estos incendios?

• El incremento de población urbana en el paisaje rural (chalets, urbanizaciones, actividades de fin de semana, etc…) aumenta la probabilidad de igniciones. Esto es debido a que muchas actividades humanas generan chispas o igniciones, tanto de manera accidental (vehículos, soldaduras, cocinas, cigarros, cableados, barbacoas, …) como intencionada (malhechores y pirómanos).
• La disminución de la población rural (reducción del pastoreo, agricultura, recolección de leña, etc..) durante las últimas décadas conlleva un incremento de la cantidad de vegetación (combustible) en el paisaje. De manera que si se da un incendio, es más probable que sea de mayor tamaño e intensidad que anteriormente cuando el uso del monte era intenso.
• La elevada sequía y las elevadas temperaturas hacen que la vegetación sea muy inflamable, y una fuente de ignición (chispa, etc.) pueda ser fuente de un incendio. El cambio climático aumenta la frecuencia de estas situaciones.
• Los vientos de poniente en Valencia son muy secos, cálidos y relativamente fuertes. Si hay un incendio en estas condiciones, el fuego se propaga rápidamente y es prácticamente imposible detenerlo, hasta que no cambian las condiciones del viento.

Los días 28 al 30 de Junio de 2012 en Valencia se dieron todos estos factores. Las condiciones climáticas eran extremas, con temperaturas elevadas  (las máximas rondando 40 grados) y humedad muy baja (hacía al menos 2 meses que no llovía); en esas condiciones, las chispas prenden fácilmente. Además, hubo tres días seguidos de vientos secos y sin cambio de dirección (el poniente), que facilitó la rápida propagación del fuego. Los dos incendios que se dieron esos días afectaron aproximadamente a un total de 50000 ha. Los incendios se controlaron cuando el poniente calmó.

¿Qué podemos hacer para evitarlos?

No es fácil, y se requiere una política a largo plazo. La simple extinción no es suficiente, tal como hemos visto en muchas ocasiones, tanto en nuestro país como en otros (incluidos países tecnológicamente más avanzados y ricos). Aquí algunas ideas:

• Disminuir la población urbana que vive en los paisajes inflamables, es decir, disminuir los chalets y urbanizaciones que tenemos en nuestros montes, reducir la interfaz urbano-forestal. En general las urbanizaciones en el medio natural son: 1) potenciales puntos de ignición; 2) puntos de desastre cuando se da un incendio (a menudo los incendios no son perjudiciales para la vegetación, que se regenera, pero causan problemas a los habitantes que viven en el monte); 3) son en sí mismos un problema para la biodiversidad, independientemente de los incendios (destrozan parte del paisaje y de la naturaleza, incrementan las especies invasoras, etc…).
• Incentivar la vida rural y el uso sostenible de los montes. Introducir o facilitar a la presencia de herbívoros autóctonos (y sus depredadores).
• Reducir el cambio climático, es decir, reducir las emisiones de gases efecto invernadero y cumplir con los protocolos de Kyoto sobre el cambio climático. Reducir el uso de energías contaminantes, etc.
• Aceptar que siempre habrá incendios en nuestros montes mediterráneos, y aprender a vivir con ello. Diseñar con detalle las zonas donde se puede construir y donde no; limitar fuertemente el paso en los caminos rurales, especialmente en épocas propensas a incendios; regular las construcciones y sus alrededores considerando los incendios como parte del paisaje.

 Valencia, 30 Junio 2012.

Para más información:

Libro: Incendios forestales, Ed. Catarata-CSIC [enlace]

Incendios de ayer, de hoy y de mañana, Crónica Popular 6/7/2012  [enlace | pdf]

Pausas J.G. & Paula S. 2012. Fuel shapes the fire-climate relationship: evidence from Mediterranean ecosystems.  Global Ecol. Biogeogr. [doi | pdf | post]

Pausas J.G. & Fernández-Muñoz S. 2012. Fire regime changes in the Western Mediterranean Basin: from fuel-limited to drought-driven fire regime. Climatic Change 110: 215-226. [doi | pdf | post]

Pausas, J.G. 2004. Changes in fire and climate in the eastern Iberian Peninsula (Mediterranean basin). Climatic Change 63: 337-350. [doi | pdf]

Pausas, J.G., Vallejo R. 2008. Bases ecológicas para convivir con los incendios forestales en la Región Mediterránea – decálogo Ecosistemas, 17(2): 128-129 (5/2008). [link | pdf]

Urban planning for fire management [link]

Book: Fire in mediterranean ecosystem [link]

The answer is blowing in the wind [link]

Fire are often considered disasters when they destroy infrastructure and lives (independently of the ecological effects); this is specially important in mediterranean-type climate regions where there is a high density of houses in the wildland-urban interface. The most common management action to avoid these disasters are based of fuel reduction (fuel breaks, prescribed fires, etc). However, these actions do not seems to be very successful, at least in crowded regions and where fire occur in extreme weather situations. For instant, in southern California nearly 1000 homes per year have been destroyed by wildfires since 2000, despite their fire management plans. In addition, strong fuel reduction actions have negative biodiversity implications (vegetation degradation, alien invasion, etc.). In a recent paper, Syphard et al. [1] suggest that urban planning could be more efficient in reducing disasters and property losses from fire than fuel management. They found that at the regional scale, fuelbased maps did not predict property loss as well as maps developed using a combination of factors that included housing arrangement and location. Consequently land use planning and housing development policies should be important components of fire risk management plans for the wildland-urban interface.

[1] Syphard A.D., Keeley J.E., Massada A.B., Brennan T.J. & Radeloff V.C. (2012). Housing arrangement and location determine the likelihood of housing loss due to wildfire. PLoS ONE, 7, e33954.

Mediterranean cork oak (Quercus suber) savannas, which are found only in southwestern Europe and northwestern Africa, are ecosystems of high socioeconomic and conservation value. Characterized by sparse tree cover and a diversity of understory vegetation, these ecosystems require active management and use by humans to ensure their continued existence. The most important product of these savannas is cork, a non-timber forest product that is periodically harvested without requiring tree felling. Market devaluation of, and lower demand for, cork are causing a decline in management, or even abandonment of cork oak savannas. Subsequent shrub encroachment into the savanna’s grassland components reduces biodiversity and degrades the services provided by these ecosystems. In contrast, poverty-driven overuse is degrading cork oak savannas in northwestern Africa. “Payment for ecosystem services” schemes, such as Forest Stewardship Council (FSC) certification or Reducing Emissions from Deforestation and Degradation and enhancement of carbon stocks (REDD+) programs, could produce novel economic incentives to promote sustainable use and conservation of Mediterranean cork oak savanna ecosystems in both Europe and Africa.

Bugalho M.N., Caldeira M.C., Pereira J.S., Aronson J., & Pausas J.G. 2011. Human-shaped Cork oak savannas require human use to sustain biodiversity and ecosystem services. Frontiers in Ecology and the Environment 9: 278-286 [doi | pdf] [featured on the cover: pdf, foto]  podcast

Aronson J., Pereira J.S., Pausas J.G. (eds). 2009. Cork Oak Woodlands on the Edge: conservation, adaptive management, and restoration. Island Press, Washington DC. 315 pp. [the book]

More posts on oaks.

Foto: D. Crespo (Portugal)

One key difference between animals and humans is the use of fire; in fact, during the evolution, fire made us humans. For instance, cooking implied higher food energy, as well as an increased the diversity of available food (detoxifying effects of heating, etc…). Furthermore, cooking implied a delay in food consumption, which required the development of social abilities for the distribution of tasks within the group (e.g., collection, accumulation, cooking, defense, even stealing). These factors are thought to have prompted the evolution of large brains and bodies, small teeth, modern limb proportions, and other human traits, including many social aspects of human-associated behavior. However, the moment in which humans started to use fire is still debated. It is often believed that the rise of Homo erectus from its more primitive ancestors was fueled by the ability use fire.

Although the use and control of fire is a human trait, a recent study has demonstrated that chimpanzees have the ability to understand wildfires and predict their behavior (Pruetz & LaDuke 2010). Chimps calmly observed wildfires around them, predict their behaviour and move accordantly without any stress or fear. This suggest that the conceptualization of fire may be a old trait, in the hominids group.

To what extent current humans are losing this trait is another debate, but we may be better off at managing our fire-prone landscapes by learning from chimps!

References

• Pausas J.G. & Keeley J.E. 2009. A burning story: The role of fire in the history of life. BioScience 59: 593-601 [doi] [pdf]
• Pruetz JD & TC LaDuke 2010. Reaction to fire by savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal: Conceptualization of  fire behavior and the case for a chimpanzee model. Am J Phy Anthropol (in press) [doi]
• Wrangham RW, Jones JH, Laden G, Pilbeam D, Conklin-Brittain NL. 1999. The raw and the stolen: Cooking and the ecology of human origins. Current Anthropol 40: 567–590.
• Control of fire by early humans [Wikipedia]

2010

• 2nd Human Dimensions of Wildland Fire Conference, San Antonio, Texas, USA, April 26-29, 2010 [web]
• Spatial and temporal patterns of wildfires: models, theory, and reality, European Geosciences Union, General Assembly 2010, Vienna, Austria, 02 – 07 May 2010, [web]
• 2nd International Conference on Modelling, Monitoring and Management of Forest Fires, Kos, Greece, 23 – 25 June 2010, organised by Wessex Institute of Technology, UK [web]
• 3rd Fire Behavior and Fuels Conference: Beyond Fire Behavior and Fules: Learning from the Past to Help Guide Us in the Future. Hosted by: International Association of Wildland Fire; 25-29 October, 2010, Spokane, Washington, USA [web]
• 6th International Conference on Forest Fire Research, Coimbra, Portugal, 15-18 November 2010 [web]

2011

• 3rd International Meeting of Fire Effects on Soil Properties, University of Minho, Guimarães, Portugal, March 15-19, 2011 [web].
• Catching Fire: New Methods and Research for Identifying Anthropogenic Fire and Landscape Modification, Sesion in the 76th Annual Meeting of the Society for American Archaeology, March 30 – April 3, 2011, Sacramento, California [web]
• 5th Intarnational Wildland Fire Conference, Sun City, South Africa, 9-13 May 2011 [web], organised by the IAWF

We all now about the over-exploitation and over-hunting in many ecosystems, including the Amazonian forests. Recently, travelling in Brazil I found some figures on the magnitude of the hunting in the Amazon, they are unbelievable:

Number of animals legally exported from one single port (Iquitos, a river port in the Peruvian Amazon) during 5 years (1962-1967):

183,664 – Monkeys
149,256 – Caiman species (Melanosuchus and Caiman)
67,575 – Capybaras (Hydrochaeris)
47,851 – Otter (Lutra)
2,529 – Giant otter (Pteronura)
61,499 – Ocelots (Leopardus pardalis = Felis pardalis)
9,565 – Margay (Leopardus wiedii = Felis wiedii)
5,345 – Jaguar (Panthera onca)
690,210 – Collared Peccary (Pecari tajacu = Tayassu tajacu)
239,472 – White-lipped Peccary, Tayassu pecari,
239,470 – Deer (Mazama)

Total > 1.6 millions of animals!

But, you need to add those that were hunted for local consumption (estimated to be as many as to those hunted for legally exporting, above), and those hunted illegally (estimated to be much more that those hunted legally). And this is only for one single port, for a only 5 years, and only for large mammals and caimans … (birds, turtles, lizards, etc… are also hunted). This strong defaunation of vertebrates has implication not only on animal biodiversity but it has also cascading effects on ecosystems (e.g., reducing predation, herbivory, dispersal of plants, etc.). [more info: R. Dirzo]

The Amazon is now a great place for any biologist, how would it be if it was not an empty forest!

MISR image of the Central Amazon showing the city of Manaus, the meeting-of-the-waters where the Rio Negro and Rio Solimoes merge.

Sources:
Fenandéz, F. 2009. O poema imperfeito, 2on ed., UFPR editora.
Redford, K.H. 1992. The empty forest. BioScience, 42(6), 412–422.

Fire management is facing two extreme views (see a discussion and references in PDF):

• Large fires are controlled by fuel, and are the consequence of the fire suppression policy (build-up of fuels). Thus to reduce fire danger, fuel control is needed (the patch mosaic model)
• Large fires are controlled by climate (mainly severe droughts) and thus fuel management is of little relevance

A recent paper is conclusive in that in California, large chaparral fires are controlled by climate and they burn through a vegetation mosaic of differetn ages since fire, and thus in landscapes under severe weather conditions there is little hope fuel treatments will provide barriers to fire spread. Strong dry winds, Santa Ana winds, are driving many of the large chaparral fires (Figure below).

Keeley, J.E. and P.H. Zedler. 2009. Large, high intensity fire events in southern California shrublands: debunking the fine-grained age-patch model. Ecological Applications 19:69-94. [journal] [pdf] [brief for managers]

Santa Ana wind-driven fires (MODIS, 26 Oct 2003)

Fires in the Mediterranean basin: The question is weather these results also apply to other Mediterranean regions. The role of droughts in recent fires (e.g., see the 2007 European heat wave and the consequences on large fires in Greece and Croatia; Figures below) and the importance of dry winds in many fires (e.g., ponientes in eastern Spain) suggest that a similar process may be occurring in the Mediterranean basin, although due to the long and intense land use in this area, fuel structure may also need to be considered for understanding some past fire regime changes [pdf].

Temperature anomalies in Europe, summer 2007

Fires in Greece, summer 2007

Some summaries for the 2009 wildfires in Mediterranean regions:

• Mediterranean Basin [wikipedia]:  Greece [wikipedia]
• California [wikipedia | NOAA images | comments by JE Keeley ]
• Australia [wikipedia]: Victoria (Black Saturday bushfires) [wikipedia | video |  wikipedia-ES]
• Cape, South Africa [wikipedia]

• Southern California Public Radio, Program: Patt Morrison –  August 31, 2009 [link]
• Southern California Public Radio, Program: AirTalk – September 1, 2009 [link]
• High Country News – September 4, 2009 [link]

Pausas, J.G. & Vallejo R. 2008. Bases ecológicas para convivir con los incendios forestales en la Región Mediterránea – decálogo. Ecosistemas 17(2): 128-129, 5/2008. [link] [pdf] – Ecological bases for coexisting with forest fire in the Mediterranean Region – Decalogue. [English version: pdf]

En nuestra sociedad existe cierta tendencia a pensar que los incendios forestales son un desastre que hay que evitar a toda costa, ya que destruyen nuestros ecosistemas. Esta idea ha sido adoptada también por muchos gestores de montes y áreas protegidas. Sin embargo, los grandes presupuestos destinados a la extinción no parece que hayan conseguido detener los incendios, incluso en países con mayores recursos económicos que el nuestro, lo que hace dudar de la eficacia de estos programas y del paradigma sobre el que se asientan. Por otro lado, numerosas evidencias sugieren que los incendios forestales han existido desde muy antiguo y no tienen porqué suponer un desastre ecológico, si se mira a la escala apropiada. Esta nueva visión requiere un cambio de paradigma y la adaptación de éste a la gestión y restauración de nuestros ecosistemas. Con este objetivo, proponemos aquí 10 puntos que esperamos estimulen la discusión, y contribuyan a definir mejor las prioridades en la gestión de nuestros ecosistemas. Read more…