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Keywords:

  • degradation thresholds;
  • disperser-mediated facilitation;
  • ecosystem functioning;
  • landscape ecology;
  • nucleation;
  • restorability;
  • seed dispersal;
  • stable alternative states;
  • succession

Abstract

Valladares and Gianoli (2007) tried to answer a key question, “how much ecology do we need to know to restore Mediterranean ecosystems?” by focusing on (1) plant–plant interactions; (2) environmental heterogeneity and the potential adaptation of transplanted plants; and (3) phenotypic plasticity of the planted species. We consider their choice of topics incomplete and potentially misleading because (1) it is clearly biased toward a narrow set of research topics (phenotypic plasticity, facilitation, and climate change); (2) it assumes that active restoration, and specifically revegetation, is needed; and (3) it conveys a false perception that other basic ecological aspects of Mediterranean ecosystems are sufficiently known. Instead, we review the current knowledge on seed dispersal, succession, and ecosystem functioning for Mediterranean ecosystems. We argue that decades of research on these topics have yielded few practical guidelines for restoration, something that needs to be urgently corrected. First, the current “establishment limitation paradigm” for plant recruitment does not acknowledge the role of dispersal limitation at large spatial scales. More attention should be paid to nucleation processes and directed seed dispersal mediated by animals. Second, studies of vegetation dynamics and succession in the Mediterranean have led to an overly simplistic view of successional dynamics. How fast and deterministic succession is remains mostly unexplored; long-term monitoring of successional dynamics at different spatial scales is urgently needed. Third, information on the functional status of Mediterranean ecosystems is required to identify processes hindering natural recovery after disturbances and to set priorities on the areas and ecosystem components to be restored.