Brightsurf.com reports on a study published in the journal Proceedings of the National Academy of Sciences finds that microscopic animals that live in soils are as diverse in the tropical forests of Costa Rica as they are in the arid grasslands of Kenya, or the tundra and boreal forests of Alaska and Sweden.
The Brightsurf.com article refers to the accepted wisdom of a wider range of species being found above ground at the equator than at the Earth's poles. But this study proves for the first time that the same rules don't apply to the nematodes, mites and springtails living underground.
Soil samples taken from a range of habitats in 11 sites around the world each hosted a diversity of soil organisms, identified through DNA testing. Each of these ecosystems was found to be unique with its own soil animals – illustrating an "amazing diversity of species" that had never been discovered before.
But 96% of identified soil animals were found at only a single location, suggesting that most soil animals have restricted distributions, or in other words, they are endemic. This challenges the long-held view that these smaller animals are widely distributed. However, unlike most above-ground organisms, there was no indication that latitude made a difference in soil animal diversity. In fact, sites with greater aboveground biodiversity appeared to have lower diversity beneath in soils.
Read more here.