Spatial ecology in a changing world

New articles: Fires are not that bad: impacts at the community level on birds and arthropods

Two new articles on fire-triggered ecosystem changes has been published in Ecography, as a result of a collaborative work lead by Marco Moretti and with the participation of Miquel De Cáceres, and Journal of Animal Ecology by Miguel Clavero and Lluís Brotons in collaboration with Sergi Herrando at the ICO.

It is often suggested that fire acts as an environmental filter that selects species and functional traits, and reduces trait variability within communities. Moretti et al. have studied these effects in fire-sensitive ecosystems, such as the central European Alps, where fires are scarce. The authors used two families of saproxylic beetles (i.e. Cerambycidae and Buprestidae) as model group to test the combined effect of fire and altitude on species and trait composition. Results showed an overall positive effect of fire on taxonomic and functional diversity, while indicator species and community analyses revealed that the response to fire was also modulated by altitude. The positive effect of fire and the presence of large populations of pyrophilous species suggest co-evolution with fire and adaptation to disturbance in the Alps.

In the second article we tested the hypothesis that disturbance favours generalist species within communities, analysing effects of wildfires in bird communities in a Mediterranean climate area as a case study. Using, bird occurrence data in more than 500 1×1 km squares forming a gradient running from forest to completely burnt areas. The level of specialization of bird communities was estimated by means of three complementary species specialization indices, calculated for different landscape gradients and averaged at the community level and mean species rarity. We also calculated mean habitat preferences along landscape gradients, as well as an index of conservation value and total species richness.

Wildfires seem to play an important role for the maintenance of open-habitat, urban-avoider bird populations in Mediterranean landscapes and also to benefit a set of species of unfavourable European conservation status. In this context, it can not be unambiguously concluded that fire disturbance, even in a context in which fires are greatly favoured by human-related activities, leads to more functionally simplified communities dominated by generalist species.

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Els focs no semblen tant dolents: impactes a nivell de comunitat en ocells i artròpodes

Dos nous articles tractant els canvis ecosistèmics derivats de l’acció del foc han aparegut a la revista Ecography (com a resultat d’un treball col·laboratiu dirigit pel Marco Moretti, i en el que Miquel De Cáceres ha participat); i a la revista Journal of Animal Ecology amb la participació de Miguel Clavero i Lluís Brotons en col.laboració amb el Sergi Herrando del ICO.

Sovint es suggereix que el foc actúa com un filtre ambiental que selecciona espècies i característiques funcionals, i redueix la variabilitat de caràcters dins de les comunitats. Aquest efecte ha estat estudiat per Moretti et al. en ecosistemes sensibles al foc com són els Alps centrals europeus. Els autors han utilitzat dues famílies d’escarbats saproxílics (Cerambycidae i Buprestidae) com a grup model per a testar l’efecte combinat del foc i l’altitud en la composició de caràcters i espècies de les comunitats. Els resultats mostren un efecte positiu del foc en la diversitat funcional i taxonòmica, modulada per l’altitud. La presència de grups pyrofils suggereix co-evolució amb el foc i adaptació dels ecosistemes dels Alps a la perturbació.

Clavero, M., Brotons, L. and Herrando, S (2010) Bird community specialisation, bird conservation and disturbance: the role of wildfires. Journal of Animal Ecology, in press. DOI: 10.1111/j.1365-2656.2010.01748.x

Moretti, M., De Cáceres, M., Pradella, C., Obrist, M.K., Wermelinger, B., Legendre, P. and Duelli, P. (2010) Fire-induced taxonomic and functional changes in saproxylic beetle communities in fire sensitive regions. Ecography 33(4): 760-771.



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