Mediterranean Environments

by

Harriet D. Allen

• LAST REVIEWED: 26 July 2017
• LAST MODIFIED: 26 July 2017
• DOI: 10.1093/obo/9780199363445-0076

Introduction

Mediterranean environments are found in the Mediterranean Basin itself, California (including Baja-California, Mexico), central Chile, south and southwestern Australia, and the Cape region of South Africa. They share a climate typically characterized by hot, dry summers and warm, wet winters. These climate regions occur on the western sides of continents between latitudes 23^o and 40^o north and south of the equator, and are associated with cold ocean currents. Their climatic origins date back to progressive cooling of Earth’s climate in the Late Miocene and the onset of Northern Hemisphere glaciations in the later Neogene and early Quaternary. Synergistically the selective forces of fire, geology, and climate, over millions of years, have resulted in convergence of plant traits leading to vegetation communities dominated by sclerophyllous, evergreen shrublands. Additionally, woodlands are or were extensive, such as evergreen oak woodlands in California and the Mediterranean Basin, eucalyptus in Australia, and evergreen woods in Chile. Only in the fynbos of South Africa are woodlands largely absent. Pastures and grasslands are also constituent mediterranean-type communities. While the five mediterranean regions share common environmental traits, their individuality offers the potential for comparative studies of evolutionary and ecological processes. Collaborative research started in the 1970s and has burgeoned since the 1990s with their recognition as “natural laboratories” for studying global change, as they differ less in key aspects of their biomes than other biome types that occur in more than one locality worldwide. Further, they are sensitive to several interacting drivers of such change such as biotic exchanges, land use, and climate changes. Fire is one of the key factors in explaining the contemporary ecology of mediterranean-type ecosystems, and its incidence is expected to increase as climate and land-use and land-cover changes alter patterns of fuel (vegetation) accumulation; this is a major area of current research. Each of the regions is recognized as a biodiversity hotspot subjected to intense pressures from their human populations.

General Overviews

One of the first edited volumes to synthesize research in Mediterranean ecosystems is di Castri and Mooney 1973, which focused on their origins and structure, especially convergent evolution of plants. In the same Ecological Studies series, Moreno and Oechel 1994 and Moreno and Oechel 1995 focused on fire and on global change, while Davis and Richardson 1995 examined the function of biodiversity, and Rundel, et al. 1998 examined landscape disturbances and biodiversity. All of these texts introduced key research areas of continuing interest. Recent, excellent, and very well-illustrated introductions to the individual mediterranean-climate regions are provided in Allsopp, et al. 2014 for the Fynbos of the Cape Floristic Province; Blondel, et al. 2010 for the Mediterranean region; and Mooney and Zavaleta 2016 on the ecosystems of California. Threats to mediterranean ecosystems were included in Sala, et al. 2000, a review of biodiversity in the year 2100. Doblas-Miranda, et al. 2015 assesses more current research priorities in mediterranean environments.

• Allsopp, N., J. F. Colville, and G. A. Verboom. 2014. Fynbos: Ecology, evolution and conservation of a megadiverse region. Oxford: Oxford Univ. Press.

  DOI: 10.1093/acprof:oso/9780199679584.001.0001

  A synthesis of research on the fynbos and succulent karoo regions of the Cape Floristic Kingdom, South Africa, focusing on ecological and evolutionary research, including major advances in genetic research that allow a better understanding of this biodiverse region’s floristic origins.

• Blondel, J., J. Aronson, J. -Y. Bodiou, and G. Boeuf. 2010. The Mediterranean region: Biological diversity in space and time. Oxford: Oxford Univ. Press.

  This is the second edition of Blondel and Aronson’s earlier book (1999). It has expanded on the original to include chapters on coastal areas and the Mediterranean Sea itself. It provides an excellent introduction to the region’s ecology and physical geography covering countries around the sea.

• Davis, G. W., and D. M. Richardson, eds. 1995. Mediterranean-type ecosystems: The function of biodiversity. Berlin: Springer-Verlag.

  This is one of the earliest books to examine biodiversity and ecosystem functioning. It argues that mediterranean-type ecosystems provide good opportunities for testing hypotheses relating to biodiversity and ecosystem function at all scales. Authors come from all five mediterranean regions and chapters are geographically specific, but with a conclusion synthesizing research and setting agenda for the 21st century.

• di Castri, F., and H. A. Mooney, eds. 1973. Mediterranean-type ecosystems: Origin and structure. Papers presented at the first MEDECOS conference, held in Valdivia, Chile, 1970. New York: Springer-Verlag.

  MEDECOS conferences are a series of meetings that bring together researchers with an interest in mediterranean-type ecosystems. This volume is derived from the first MEDECOS conference held in Valdivia, Chile, in 1970 on the theme of convergent evolution.

• Doblas-Miranda, E., J. Martinez-Vilalta, F. Lloret, et al. 2015. Reassessing global change research priorities in mediterranean terrestrial ecosystems: How far have we come and where do we go from here? Global Change Biology 24:25–43.

  DOI: 10.1111/geb.12224

  This paper revisits mediterranean global change research priorities identified by S. Lavorel, J. Canadell, S. Rambal, and J. Terradas, “Mediterranean Terrestrial Ecosystems: Research Priorities on Global Change Effects,” Global Ecology and Biogeography Letters 7 (1988): 157–166. It evaluates progress in addressing the original priorities and updates these, for example enhancing resilience in ecosystems and addressing the linkages between ecosystem services and their functions. Both of these are emerging foci in global change research.

• Mooney, H. A., and E. Zavaleta, eds. 2016. Ecosystems of California. Oakland: Univ. of California Press.

  This richly illustrated and edited book has a four-part structure: drivers of patterns and processes in the Californian landscape, such as climate, soils, fire, and land use; a historical context for ecosystem development; biotic patterns and threats to ecosystems; and individual chapters for different ecosystems, including mediterranean coastal sage scrub, grasslands, chaparral, and oak woodlands.

• Moreno, J. M., and W. C. Oechel, eds. 1994. The role of fire in mediterranean-type ecosystems. New York: Springer-Verlag.

  A multiauthor overview on how fires impact on mediterranean ecosystems. It is useful as a benchmark text to show how research in this key area has developed since the 1990s.

• Moreno, J. M., and W. C. Oechel, eds. 1995. Global change and mediterranean-type ecosystems. New York: Springer-Verlag.

  An edited volume that synthesized 1990s knowledge of the ways in which these ecosystems might respond to global changes. At publication, its importance lay in its changing focus from the scale of leaves through ecosystems to landscapes.

• Rundel, P. W., G. Montenegro, and F. M. Jaksic, eds. 1998. Landscape disturbances and biodiversity in mediterranean-type ecosystems. Papers presented at a MEDECOS conference, held in Crete, Greece, 1991. New York: Springer-Verlag.

  Derived from a MEDECOS conference held in Crete, Greece, in 1991 with a focus on landscape degradation. This was a period of intense research interest in the possibility of desertification in mediterranean-climate regions—see Land Degradation, Desertification, and Management for Conservation for further commentary on this topic.

• Sala, O. E., F. S. Chapin III, J. J. Armesto, et al. 2000. Global biodiversity scenarios for the year 2100. Science 287:1770–1774.

  DOI: 10.1126/science.287.5459.1770

  This highly influential paper identified five major drivers of global change (land use, climate, nitrogen deposition, biotic exchange, and atmospheric CO₂) and predicted their impact on biodiversity of Earth’s biomes. Biodiversity in mediterranean ecosystems is regarded as sensitive to all five drivers, but especially biotic exchanges and land-use changes. Considering the synergistic interactions among these drivers, mediterranean ecosystems are predicted to experience some of the greatest biodiversity losses.