Cape Region's flourishing flora due to soil diversity The Cape Region on the south-western tip of Africa has long been heralded as a place blooming with flowers and plants, and now an international team of EU-funded scientists has uncovered the reason behind the region's flourishing flora. It seems this remarkable plant diversit... The Cape Region on the south-western tip of Africa has long been heralded as a place blooming with flowers and plants, and now an international team of EU-funded scientists has uncovered the reason behind the region's flourishing flora. It seems this remarkable plant diversity occurs as a result of the large range of different soils present in the region, according to the team of scientists from the Germany, South Africa, the United Kingdom and the United States. Published in the journal Systematic Biology, the study, which was given a boost from the project HOTSPOTS ('Understanding and conserving Earth biodiversity hotspots'), funded in part under the Marie Curie Actions thematic area of the Sixth Framework Programme (FP6), outlines the scale of the Cape Region's flora. Being home to over 9 000 different types of plants is quite remarkable for such a small region, particularly when this figure is contrasted with Germany for example, a country 4 times the size that can only lay claim to having around 3 300 species of plant. The Cape Region can also boast to being made up of around 70?% of plants which are native to the region. Scientists have long wondered about the reasons for the high plant diversity here and have come up with a number of explanations. 'The most accepted ideas are that it either results from the high diversity of soil types or from adaption to pollinators. This means many plant species have specialised on different pollinators, such as certain insects. Pollen will only be distributed by them.' explains lead researcher Dr Jan Schnitzler, from the Biodiversity and Climate Research Centre, (BiK-F) in Frankfurt, Germany. The team tested these theories by carrying out a genetic analysis of plant species in the region. They looked at around 470 native plant species from 3 of the 7 largest plant families of the Cape region. By drawing up family trees using molecular genetic data and correlating it with information on plant ecology and the geography of the habitat, the team were able to establish how plant species diversify. The study focused on sister-species comparisons in order to assess the impact of other factors on speciation. The results showed that indeed soil type shifts were the most important cause of speciation in the majority of plants. 'The Cape region comprises many different soil types on a relatively small space which turns out to be very important in the development of plant diversity,' says Dr Jan Schnitzler. 'The reason is probably that it forced closely related species to develop adaptations to varied circumstances. Surprisingly for us, pollinator specialisation is not a general factor that drives radiation here.' The research indicates that plant diversity is not a result of rapid radiation triggered by climatic changes. Rather, plant diversity came about after a continuous process which took place over a long period of time. It also seems that the relative climatic stability in the Cape could be the reason behind low extinction rates, compared to northern Europe where many plants were wiped out as a result of several ice ages. The findings also contradict previous studies which show that pollination syndromes in plants like orchids show a high degree of phylogenetic conservatism. This combination of complex environmental conditions together with relative climatic stability is therefore what leads to high speciation and/or low extinction rates resulting in the flourishing plant life found in the Cape Region that we know today. The project HOTSPOTS puts the spotlight on 25 of the world's richest and most threatened reservoirs of biodiversity in order to increase knowledge and understanding of these areas; the dynamics of biodiversity in these hotspots and the ecological impacts of predicted biodiversity loss are still poorly understood. These areas were chosen based on plant and vertebrate species' richness, endemism and how much they are under threat. A consortium of partners will work towards applying field, molecular and bioinformatics approaches to flagship plants and animals; HOTSPOTS will train a new generation of multidisciplinary biologists in state-of-the-art methods of evolution analysis, ecology and conservation. The biodiversity paradox is that while the earth's biodiversity is threatened by the activities of human beings, human beings depend on the sustainable use of biodiversity. Jan Schnitzler explains how future research from this study could build on these findings. 'The next thing would be to test whether a large number of soil types is also the main cause for plant species radiation in other regions.' Therefore the focus could now turn to regions with a similar climate to the Cape Region such as the Mediterranean basin, California and south-west Australia.For more information, please visit:Biodiversity and Climate Research Centre, (BiK-F):http://www.bik-f.de/root/index.php?page_id=57&PHPSESSID=n9d21l4jmkl4rmdcevggbeke1t1mc8e1 Countries Germany, United Kingdom, United States, South Africa
