Vegetation Management for Promoting Ecosystem Resilience in Fire-Prone Mediterranean Shrublands

Dense shrublands constitute highly hazardous fuels in Mediterranean countries. The combination of agricultural land abandonment and fire occurrence in many Mediterranean areas has led to a landscape dominated by shrublands where resprouter species are scarce or absent. Major goals in the management of these areas are to reduce both the fuel loads and their continuity and increase the resilience of the ecosystems by introducing resprouter species. We investigated the performance of one-year-old seedlings of native resprouters, that is, Pistacia lentiscus, Quercus ilex, and Rhamnus alaternus, in a combination of vegetation clearing and mulching with brush chipping in three sites with high amount of fuel load. The planting holes inside the shrublands showed lower radiation and soil surface temperature than those in the cleared areas, whereas soil water content was higher in the mulched holes than in the unmulched ones, especially when water availability was lowest. Seedling survival of Q. ilex and R. alaternus significantly increased within the shrubland; P. lentiscus showed the opposite effect, but its survival was enhanced by the mulching treatment. The three species grew faster in the cleared plots although, unexpectedly, mulching showed a negative effect on Q. ilex relative growth rate in diameter. Our results suggest that the combination of fuel control and reforestation as techniques for shrubland management is an appropriate option, at least in the short term, to redirect vegetation dynamics toward later successional stages, improving ecosystem resilience by the introduction of woody resprouter species.