Half Neck
Ten percent: Every nation on earth should reserve this much land for nature conservation. What sounds like little is overwhelmed by many states - it means setting priorities when selecting the area. But which ones?
You have to look for wild nature in Germany with a magnifying glass: Not including the water areas on the North Sea and B altic Sea, just under half a percent of the country's area is under the protection of a national park. And even if you add all nature reserves - and thus a similarly high degree of protection - it remains at a modest 2.5 percent. This means that the Federal Republic falls well short of the area tenth internationally specified as the minimum for the protection of flora and fauna.
It looks much better in South Africa, where as of 2003, 6.2 percent of the national territory is strictly reserved for animals and plants - nevertheless, here, as probably almost everywhere in the world, major conflicts of interest arise between pure wilderness and human Use in the form of road and urban construction, agriculture, forestry and mining. When selecting the areas to be protected, it is therefore important to set priorities so that as many species and ecosystems as possible are preserved. Governments and environmental organizations prefer to use the so-called biodiversity hotspots, where a large number of endangered and unique species live in a relatively small area. But is this actually the right concept?
Félix Forest from the Kirstenbosch Research Center in Claremont, South Africa, and his colleagues are of two minds. Your primary research area is right on your doorstep: the Kapensis floral kingdom. With only 90,000 square kilometers it is the smallest of this botanical classification and yet one of the most species-rich areas on earth. About seventy percent of the 9000 known plant species - including famous garden, ornamental and cut flower plants such as geraniums, pelargoniums or strelitzias - only occur here and make the South African bush landscape called fynbos an interesting field of scientific activity. By way of comparison, the UK grows only one-sixth that number in an area three times as large.
Within the capensis, there is a west-to-east trend with the highest numbers of species and endemics in the more Mediterranean winter rain area directly on the Cape and the Atlantic coast, which decreases to the east with increasing, more and more year-round precipitation. Consequently, conservation focuses on the centers of diversity and somewhat negates the more monotonous regions further east. But that could turn out to be a bit hasty, as the scientists conclude based on the phylogeny of the Cape flora: They reconstructed the family tree of 735 native genera based on certain gene sequences of the plants and calculated their family relationships on the computer.
Here, too, there was a clear west-east contrast that apparently supports previous assessments - with one crucial difference: the phylogenetic diversity was now higher in the east than in the west. In plain language: the biodiversity around Cape Town is based on a we alth of closely related genera that have diverged in manifold ways over the last 25 million years. On the other hand, many species in the east are quite distant and therefore belong to evolutionarily distinct lineages, since here in the border area to another species-rich area - the Maputoland-Pondoland-Albany - completely new taxa are already appearing and mixing with the Cape flora.
In order to gain a maximum increase in protected evolutionary diversity, the protective measures would have to increasingly address the eastern half of the capensis - after all, according to Forest's team, this is the only way to ensure the best possible biological range for the future development of local biodiversity. Critics could now object that the high number of species in western South Africa proves effective and active and therefore sustainable speciation, which in turn underlines the concentrated measures here.
Félix Forest and his colleagues counter this argument with another data set that divides the genera examined into the three usage categories of nutrition, medicine and other - provided they are used in this way. And again, the calculations show that the genera in question were scattered widely across the family tree: if protection was concentrated on a specific aspect, the other two groups were mostly left out; for example, because the food plants were closely related and lived primarily in the west, while the medicinal herbs were distributed among a few, mutually alien species in the east. As a result, humanity might lose some of its plant potential because it would have focused on sheer mass and not on the best possible evolutionary range.
But they didn't want to thwart or even reject the most recent protection efforts on the west coast of South Africa, according to the researchers. Rather, additional areas further east would have to be integrated into the national reserve concept – a general increase would be desirable. At least on this point, all conservationists from Germany to South Africa should be pretty much in agreement.
