Attractive and "interesting" animals such as butterflies, birds and mammals have been studied in much more detail than lower orders of animals. Although such "interesting" species make up only a small proportion of the total number of species on the planet, the knowledge we have of them to a large extent determines the supposed diversity of a particular biotope as a whole. By concentrating on the humble terrestrial flatworm, biologists from the Zoological Museum at Amsterdam University (UvA) have discovered three new "hotspots" of biological diversity: New Zealand, Southeast Australia and Tasmania. The study formed part of the NWO¹s Priority Programme on Biodiversity within Disturbed Ecosystems.
The terrestrial flatworm, of which there are about 822 different species, can act as a model for the distribution of lower invertebrates. The biological diversity of this predator among the soil faunawhich is hardly preyed on by other animals also reflects the diversity of organisms within the soil fauna. The soil fauna plays a key role in many ecosystems. Areas which were already considered "hotspots" of biodiversity, such as the coast of Brazil, Java and Sri Lanka, also turn out to be rich in different species of terrestrial flatworm. There is also a great diversity of these creatures in the hotspots for higher plants: New Caledonia, Madagascar and Sumatra. The terrestrial flatworm s therefore a good indicator of biodiversity. By analysing the available literature, the biologists also discovered three new hotspots which indicate a great diversity of soil organisms.
Human activity is causing the rapid extinction of plants and animals all over the world. This "biodiversity crisis" is considered to be one of the most pressing global problems. To save as many flora and fauna species as possible, biodiversity hotspots must first be identified. However, studies of biodiversity have hitherto taken insufficient account of the soil fauna and the lower animals, even though more than a million species of invertebrates such as worms, insects and molluscs are known. This is an enormous biodiversity when compared with only about 10,000 species of birds, 4500 species of mammals and 300,000 species of plants.