Improving post-fire forest management to promote biodiversity in the Mediterranean ecosystems

The Conservation Biology Group undertook a specific project reported in the European Journal of Wildlife Management, studying the rabbit populations in different areas of the Sant Llorenç del Munt i l’Obac natural park, which in August 2003 was hit by a forest fire that burned some 4,600 hectares. The basic objective was to study how forest fires and post-fire forest management affected the abundance and recovery of rabbit populations, which is a key species in Mediterranean ecosystems since it is a staple pray for many endangered predators as the Bonelli’s Eagle.

The Group looked at fifty different plots of land corresponded to one of four different types: natural areas not burned, burned areas where burned branches were left in situ (resulting from the removal of burned wood with a certain commercial value), burned areas where all burned wood was removed, and areas of low vegetation cover before the fire. Interesting results were obtained. In the burned areas, rabbit populations recovered faster and reached high abundances five years after the fires had occurred, far surpassing population numbers in unburned areas. Additionally, in burned areas where the burned branches were removed, rabbit populations grew faster and reached higher abundances than in plots where the burned branches were left on the ground. Finally, close analysis taking into account the different layers of vegetation and burned wood showed a strong negative correlation between the amount of burned wood left on a plot and rabbit abundance and, in contrast, a positive correlation in the case of uncovered soil and the existence of herbs and grasses.

The reasons for these results lie, firstly, in the fact that fires ‘open up the landscape’, and that the early stages of regeneration after a fire encourage the growth of herbs and grasses of high nutritional value for rabbits, so the species can reproduce at an adequate rate. Secondly, burned branches left in situ are likely to prevent not only the movement and actions of rabbits but also the growth of these plants of high nutritional value.

Forest fires in Mediterranean areas create open habitats which benefit rabbit populations.

Therefore, this post-fire treatment is not favourable to rabbit abundance. Therefore, removing burned wood left by forest fires could contribute to the recovery of rabbit populations affected by inadequate habitats, viral diseases and overexploitation, and is essential for the conservation of highly endangered species and the future of Mediterranean biodiversity. Furthermore, the application of this technique paves the way for the use of controlled burning as a tool for the improvement and recovery of rabbit populations. Finally, this alternative approach might increase the potential financial returns obtainable from Mediterranean forests, where the value of the wood is very low and could be surpassed by income from hunting.

This study was supported by the Àrea d’Espais Naturals de la Diputació de Barcelona and the Cercle d’Amics dels Parcs Naturals.

For further information:

• ROLLAN, À. & REAL, J. 2010. Effect of wildfires and post-fire forest treatments on rabbit abundance. European Journal of Wildlife Management, 57, number 2: 201-209. doi: 10.1007/s10344-010-0412-y