The specific vulnerability of plant biodiversity and vegetation on Mediterranean islands in the face of global change

Abstract

To cite this version:Frederic Medail. The specific vulnerability of plant biodiversity and vegetation on Mediterranean islands in the face of global change.Abstract The numerous Mediterranean islands ([10,000) are very important from a biodiversity point of view, both in term of plant species (numerous endemics, presence of 'climate relicts') and of ecosystems' assemblage. These patterns can be explained by complex interactions between a highly heterogeneous historical biogeography and ecological processes related to diverse island conditions. Furthermore, most of the ups and downs of this biodiversity were closely linked with human pressures which have changed many times through the long socio-ecological history of these island landscapes since the Neolithic period. At present, insular plant biodiversity and rural landscapes are threatened by diverse global environmental changes related to urbanization, habitat fragmentation, unsustainable tourism and other practices (e.g. overgrazing, forest fires), and by other more recent drivers such as climate warming and aridification, sea-level rise and biological invasions. Some of these impacts will be exacerbated on islands because of no (or highly limited) adjacent areas of expansion, notably on the smallest ones (i.e. size \ ca. 1000 ha). With regards to the biome crisis facing the Mediterranean basin and induced by human activities, islands constitute key ecological systems and 'current refugia' to ensure the long-term preservation of coastal plant biodiversity. They also represent fascinating ecological systems to disentangle the role of environmental versus human pressures on spatially simplified communities of the Mediterranean coastal areas. Future detailed studies of these 'natural island microcosms' could greatly improve our knowledge of the functional and evolutionary processes induced by rapid environmental changes in this region.

Mapping and Understanding the Dynamics of Landscape Changes on Heterogeneous Mediterranean Islands with the Use of OBIA: The Case of Ionian Region, Greece

“…Islands located at the northeast Mediterranean basin constitute heterogeneous and dynamic landscapes driven primarily by natural factors and processes and the long term presence of human and their related activities [6,51]. Wood cutting for energy and construction, livestock breeding, agriculture and wildfires, which are again affected by the topographic conditions and remoteness, formed traditionally the main drivers of shaping those landscapes.…”

“…Mediterranean islands exhibit a complex history of interactions between natural and anthropogenic processes which resulted in high biodiversity and high aesthetic and cultural values [2,6]. They are vulnerable to environmental changes since climate change and the projected increase of aridity, coupled with sea-level rise and changes in traditional human practices, are likely to affect many ecosystems and plant communities which are associated with high plant and animal biodiversity [50].…”

Determinants of alpha and beta vascular plant diversity in Mediterranean island systems: the Ionian islands, Greece

“…Their high plant diversity reflects their palaeogeographical history (Médail and Quézel 1999). Most Mediterranean islands belong to the two Greek archipelagos, with ca 7600 islands and islets in the Aegean archipelago and ca 300 islands and islets in the Ionian (Médail 2017).…”

Management implications based on diversity patterns under climate change scenarios in a continental island biodiversity hotspot

“…The Mediterranean Basin is a biogeographically complex area, with high levels of endemism and diversification, due to its high topographic and climate heterogeneity (Médail, 2017). It constitutes the second largest terrestrial biodiversity hotspot in the world (Médail and Myers, 2004) with nearly 12500 plant species endemic to the region, most of which have an extremely narrow geographical range (Médail, 2017). The Mediterranean islands have high overall and endemic species richness (Médail, 2017).…”

“…It constitutes the second largest terrestrial biodiversity hotspot in the world (Médail and Myers, 2004) with nearly 12500 plant species endemic to the region, most of which have an extremely narrow geographical range (Médail, 2017). The Mediterranean islands have high overall and endemic species richness (Médail, 2017). Plant endemism varies between 9-18% on the largest islands and reaches up to 40% in the high-altitude zone of their mountain ranges (Médail, 2017).…”