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Llutxent y la pérdida de suelo

October 30th, 2018 2 comments

Después de un incendio, lo peor que puede ocurrir es que haya pérdida de suelo. Por ello se aconseja visitar pronto las zonas afectadas con el fin de detectar puntos donde es posible que esto ocurra, y en su caso, poder aplicar medidas para evitarlo. En la zona mediterránea las zonas con posible pérdida de suelo suelen ser puntuales dentro del área afectada por el incendio. Estas zonas sensibles suelen estar asociadas a pendientes pronunciadas, suelos poco pedregosos, texturas arenosas, bancales abandonados, etc.. Entre las medidas para evitar la pérdida del suelo se incluye cubrir la parte sensible con paja o similar (empajado o mulching, que evita el contacto directo de las gotas de agua con el suelo), la siembra de hierbas de crecimiento rápido, o la colocación de troncos en fajas para reducir los movimientos de suelo.

En el pasado agosto ardieron unas 3200 ha en el incendio de Llutxent, afectando principalmente a los municipios de Llutxent, Gandia y Pinet (provincia de Valencia). Poco después del incendio se iniciaron acciones para proteger el suelo de la erosión, tales como la corta de pinos muertos y su colocación en el suelo en fajas. Sin embargo, estas acciones se están aplicando de forma generalizada, incluyendo zonas muy pedregosas y con poca pendiente (ver fotografías), o donde la regeneración de la vegetación es buena. En estas zonas no es previsible que haya erosión, y por lo tanto esta acción parece ecológica y económicamente innecesaria. En algunos casos, podría ser perjudicial si las acciones realizadas afectan a la regeneración natural. De hecho, con las lluvias de las semana pasadas, ya se podría evaluar si realmente ha servido para algo estas acciones y si vale la pena continuarlas.

 


Acciones que se están realizando en la zona afectada por el incendio de Lutxent (fotos tomadas en septiembre y octubre, 2018, por R. Badenes y J.G. Pausas).

 

Actualización, 27 Nov 2018: Hace unas semanas en Llutxent llovió entre 300-600 mm en pocos días, y no se ha observado erosión en sitios pedregosos y poco inclinados. A pesar de esto, se sigue aumentando las fajas para frenar la erosión … (pincha en la foto para ampliar)

 

Más información:

 

Autumn in Cazorla

October 18th, 2018 No comments

This autumn, Sierra de Cazorla (Jaén, Spain) is full of fleshy fruits, a feast for wildlife.

 

Fruits of Taxus baccatta (left), Lonicera arborea (center, white), Crataegus monogyna (right, top), Rosa sp. and Berberis hispanica (bottom, black), all taken from plants one next to the other.

 

El surar de Pinet – a small isolated population of cork oak

October 15th, 2018 2 comments

In early August, a lightning-ignited fire burned about 3200 ha of the municipalities of Llutxent, Gandia and Pinet (in Valencia, Spain): the Llutxent fire [1]. The area includes a small and isolated patch cork oak (Quercus suber; Fig. 1), the Pinet cork oak forest (locally known as el surar de Pinet) [2]. The Pinet forest (ca. 80 ha) was a mosaic of shrublands, oaks and pines (Pinus pinaster); and the fire burned most of the forest. The area is not the most optima for cork oak because of the climate (relatively dry for the species) and the soils (not too acidic). However, peripheral populations are typically genetically, morphologically and functionally different from the core populations, and can hold an important proportion of the species’ genetic diversity, thus their conservation is required.

Cork oak is a very good postfire resprouter from epicormic (stem) buds [3,4,5]. However, given that this population is in the edge of their environmental conditions, and the rainfall of the last year was below the long-term average, there were concerns about their postfire regeneration.

Happily 1 month after the fire there were some oak resprouting epicormically [1], and two month after the fire, basically all individuals were resprouting (Fig. 2). Because some plants may die after their initial vigorous resprouting [6], we should keep monitoring the resprouting of this population, but it seems that the population is saved. The fire temporally reduced the shrublands and killed most pines of the forest, and thus it could be an opportunity for managers to increase the cork population size using local acorns.

 

Fig. 1. Cork oak (Quercus suber) in the Iberian peninsula. Light grey is the species distribution; dark grey is the data from forest inventories; crosses are small isolated populations. In red is the population of Pinet (Valencia) that burned in August 2018. Map from [4]

Fig. 2. Pinet population of cork oak two months after fire with their characteristic epicormic resprouting.

References

[1] Llutxent 1 month postfire, jgpausas.blogs.uv.es/2018/09/18/

[2] Pausas J.G., Ribeiro E., Dias S.G., Pons J. & Beseler C. 2006. Regeneration of a marginal Cork oak (Quercus suber) forest in the eastern Iberian Peninsula. J. Veget. Sci. 17: 729-738. [pdf | doi | wiley ]

[3] Pausas, J.G. 1997. Resprouting of Quercus suber in NE Spain after fire. J. Veg. Sci. 8: 703-706. [doi | pdf]  

[4] 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]  

[5] Pausas J.G. & Keeley J.E. 2017. Epicormic resprouting in fire-prone ecosystems. Trends in Plant Science 22(12): 1008-1015. [doi | sciencedirect | pdf]

[6] Moreira B., Tormo J, Pausas J.G. 2012. To resprout or not to resprout: factors driving intraspecific variability in resprouting. Oikos 121: 1577-1584 [doi | pdf]

More on cork oak: posts | book | papers

 

 

Generalized fire strategies in plants and animals

October 4th, 2018 No comments

One of the unifying approaches in ecology is to search for common strategies, that is, to group species sharing mechanisms and responses to environmental factors and disturbances. Plant strategies to persist in fire-prone ecosystems (and the traits involved) are now quite well known [1]. However, less is known about fire strategies in animals, despite many fire-prone ecosystems harbor a very rich fauna [2]. This difference in knowledge is probably due to the intrinsic differences between plants (immobile) and animals (mobile) [2]. However, there is a demand for unifying plant an animals paradigms in order to better asses biodiversity in fire-prone ecosystems [3]. In a recent paper [4] I am providing an unifying framework by emphasizing the similarities between plants and animals in relation to the mechanisms for living in fire-prone ecosystems. To do so, I propose a very simple fire strategy scheme that should be valid for both plants and animals (Table 1). The advantage of having a unified framework of fire strategies include: (1) we can learn how species respond to fire from a great diversity of life forms; (2) animal and plant ecologists can benefit from shared expertise in fire responses (some common strategies in plants may be overlooked in animals, or vice-versa); (3) we could better predict changes in plant-animal interactions with fire regime changes, and (4) we could better assess and generalize the effects of fire on biodiversity. I hope this framework would facilitate finding knowledge gaps and directing future research for gaining a better understanding of the role of fire on biodiversity.

Table 1. Generalized mechanisms of species response to fire (strategy), their fire dynamics and persistence scale, and the prevalence for animals and plants in fire prone ecosystems (low, moderate, and high). The last column refers to the fire characteristics where this strategy is most likely to occur (‘high’ and ‘low’ refers to fire intensity). [4]

Fig. 1. The rhea (Rhea americana) has a cryptic coloration in postfire environments, when sitting in the ground, the neck cannot be differentiated from a burned stem. Photo: JG Pausas

 

Fig. 2. Charaxes jasius colonizing the middle of a burnt area 10 days after the wildfire that burned with very high intensity in NE Spain (note that only thick branches remained). Photo: JG Pausas.

References

[1] Keeley J.E., Bond W.J., Bradstock R.A., Pausas J.G. & Rundel P.W. 2012. Fire in Mediterranean Ecosystems: Ecology, Evolution and Management. Cambridge University Press. [the book]  

[2] Pausas J.G., Parr C.L. 2018. Towards an understanding of the evolutionary role of fire in animals. Evolutionary Ecology 32: 113–125. [doi | pdf]  

[3] Kelly L.T., Brotons L, Giljohann K.M., McCarthy M.A., Pausas J.G., Smith A.L. 2018. Bridging the divide: integrating animal and plant paradigms to secure the future of biodiversity in fire-prone ecosystems. Fire 1(2): 29. [doi | mdpi | pdf]  

[4] Pausas J.G. 2019. Generalized fire response strategies in plants and animals. Oikos 128:147-153 [doi | wiley | pdf | oikosblog]

 

A fire ecology lesson from southern Florida

October 2nd, 2018 No comments

 

How do you teach children about fire? You show them by replacing fear with a sense of wonder. 

See also: A fire ecology lesson from the Florida scrub