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Ecological impacts of wild ungulate overabundance on Mediterranean Basin ecosystems

Abstract:

The range of wild ungulates, and principally that of red deer and wild boar, has expanded throughout the Mediterranean Basin in recent decades. The abundances of these species have also increased dramatically, and they are now attaining densities that often exceed ecologically admissible thresholds. This situation has been favoured by several factors: i) The increase in shrub and forest areas owing to the cessation of marginal agricultural practices, ii) the growing demand for big game hunting and its associated intensive management actions, iii) the loss of large native predators and iv) climatic change, among others. The increase in some ungulate populations has led to agricultural damage, road accidents and the spread of shared diseases among livestock and ungulates, in addition to causing important dysfunctions at various levels of the ecosystem. In this chapter, we assess the peer-reviewed literature concerning the effects of wild ungulates on the Mediterranean Basin ecosystems. The aim of this chapter is to synthesize the knowledge regarding the ecological effects of current wild ungulate abundance on Mediterranean ecosystems, paying particular attention to the cascade effects in them. Several works have reported the negative impacts of wild ungulates, from the basic levels of the ecosystem (soil properties, nutrient cycles, microorganisms), to higher levels (vertebrates) through a series of intermediary effects on the plant community or the structure of arthropods and vegetation. These impacts on the ecosystem also promote alterations in the populations of some species whose conservation is a cause for concern, and may even lead to modifications of natural processes. All groups involved in wild ungulate management (hunters, gamekeepers, conservationists, researchers, competent authorities) should actively participate in efforts to understand, monitor, and reduce the impact of wild ungulates on ecosystems, highlighting common priorities for future research and action plans. Furthermore, addressing impacts at the landscape scale requires management policies that will integrate information regarding the negative impacts of ungulates in order to ensure an appropriate and holistic management.