Fauna

Concepts of convergence in MTEs rest for the most part on similarities in climate and vegetation across the regions. There is no apparent history of a parallel investigation of the faunal components of MTEs, nor is there any compelling evidence that regions with Mediterranean-type climates arc useful geographical units for the basis of such studies. The MEDECOS VI conference in Crete was dedicated to plant-animal interactions, but even there the

Figure 7.2 The relative extent of a Mediterranean-type climate in a sclcclion of Mediterranean basin countries and those of the other four Mediterranean-climate regions. These areas represent Koppen's Csa and Csb regions as mapped by Muller (1982)

major emphasis was on the practical issues of domestic livestock (Table 7,2). Hobbs et al. (1995a) make the point that regional faunal diversity in western Australia, which is lower than the floristic diversity, is not strongly influenced by adaptation of species to MTEs. It is, they argue, more a consequence of biogeography, and the fact that the fauna comprises species adapted primarily to other adjacent and more extreme biome types. They (Hobbs et al. 1995a) illustrate this point with the reported low levels of endemism for mammalian vertebrates (20%) and for birds (5%), while Blondel and Aronson (1995) offer a similar picture and explanation for the Mediterranean basin, with 25% and 14?/ยป endemism for mammals and birds, respectively. Glaciation during the Pleistocene comprised a set of events which probably had a marked influence on animal diversity in all of the MTEs, but especially those in the northern hemisphere. The dramatic climate changes that occurred during that period (1.2 million to 20 000 years before the present) are thought to have lead to widespread extinctions in all of the MTE regions, especially of the large herbivores. Euentes e-? al. (1995) refer to the possibility of open niches in ccntral Chile that have resulted from extinction of mammalian species during climatically harsh times, followed by a climatic improvement but with insufficient time for cither adaptation, or influx of spccies past the severe geographical barriers of sea. mountain and desert which isolate the region. The rising influence of Homo sapiens during the latter part of the Pleistocene had further effects through hunting, an action which has been linked to the disappearance of dwarf hippopotamus and elephant in the Mediterranean basin (Attenborough 1987; Diamond 1992; Blondel and Vigne 1993).

Insect diversity has been poorly studied in all of the regions, apart from in the context of agricultural management. The functional importance of insects in MTEs is, however, recognized directly in terms of the vectors of dispersal for pollen and propagules, and indirectly for its collaborative role in plant evolution. Bees are especially important pollinators in California (Keeley and Swift 1995) and Chile (Fuentes et al. i995), while the keystone role of ants as dispersers of seed has been noted both in Australia (Milewski and Bond 1982; Hughes and Westoby 1990) and South Africa (Slingsby and Bond 1985; see aiso -Section 7.4.4 below).

7.3.5 Humans in MTEs

In spite of climatic and vegetational similarities, development in the five regions has not been parallel, and different political, historical and cultural influences are all discernible.

The first and most obvious difference between countries (as currently delineated) containing Mediterranean-climate zones is the proportion of each comprising MTEs (Figure 7,2). These proportions, making adjustments of productivity in the remainder of the country, may be taken as a rough measure of the importance of MTEs in those countries. Apart from the obviously different anthropological histories on the five continents involved, it is also possible to group Mediterranean-climate regions according to their current status in modern global economic terms - the "developed"' and the "developing" countries (Figure 7.3). Of the four regions outside of the Mediterranean basin, California and Australia are distinctly developed, while Chile and South Africa have strong developing elements to their economies and socio-political structures. The Mediterranean basin, on the other hand, represents a range of countries across an extensive spcctrum which, in terms of several indicators, brackets the global set of MTE regions.

The economic indicators in Figure 7.3 suggest the different abilities of countries to invest in scientific research - the stronger the economy, the more resources there are available for basic research. This is not a fully quantifiable relationship, since resources for scientific research are not in all cases tied to broad aggregate economic indicators. Ecological work in Chile and South Africa, for instance, has benefited from a concentration of resources directed by residual colonial structures and value systems, while

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