Restoration of Mediterranean Forest Ecosystems After Major Disturbances: The Lanjarón Post-fire Experiment Over 15 Years of Succession

Abstract

Sierra Nevada faces the stark challenge of preserving and restoring biodiversity and the provision of ecosystem services in the face of ongoing shifts in natural disturbance regimes. As wildfires become more frequent, severe and widespread under human land-use changes and climate change, there is a need to understand the mechanisms that promote ecological resilience after the fire and the effects of management on such mechanisms. After the 2005 Lanjarón fire in Sierra Nevada, we established an experiment in a burnt pine stand to assess how the ecosystem responded to three management schemes: (a) salvage logging, a common strategy consisting in the felling and extraction of burnt trees; (b) partial cut, where 90% of trees were felled and cut in pieces but left scattered on the ground; and (c) non-intervention, where no action was taken. For 15 years, we monitored how different components of biodiversity and ecosystem processes and services responded to the post-fire treatments, and assessed how management affected the mechanisms that drive natural regeneration. In this chapter, we describe the Lanjarón experiment and its key scientific contributions. We first describe the insights related to the role of dead wood in promoting regeneration. This includes processes such as seed dispersal and predation, fertilization through the gradual decomposition of dead wood, microclimatic amelioration, and herbivory. Second, we portray how the community of birds, vascular plants and soil insects responded to the post-fire treatments. Whereas diversity itself was affected by management, the key responses were related to community composition. And third, we address the functions of the ecosystem related to its capacity to provide benefits to human society. We mainly address regulating ecosystem services but also analyze some provisioning services, including their economic value. In each of these three sections, we end by providing a broader, global view on the effects of salvage logging as derived from reviews that have subsequently been made under international collaborations. Altogether, the Lanjarón experiment in Sierra Nevada constitutes a unique research infrastructure that has broadened our understanding of the role of dead wood in promoting ecological resilience and whose findings have contributed to the integration of knowledge about post-fire dynamics in an international context. Additionally, ongoing monitoring aims to fill the research gap of addressing the long-term effects of a critical post-disturbance management strategy in a world facing novel disturbance regimes.