Researchers have found about 33 new species of insect and other organisms confined mainly to the mountain streams of the south-western Cape.
The findings of the new species of macroinvertebrates, made by teams from the Albany Museum in Grahamstown, the Department of Water Affairs, the universities of Rhodes and Stellenbosch, and SANParks over a 13-year period, have boosted conservation efforts to preserve the unspoilt character of these streams.
Macroinvertebrates are organisms large enough to be seen with the naked eye, but which lack a backbone. They inhabit all types of running water, from fastflowing mountain streams to slow-moving muddy rivers, and include insects in their larval or nymph form.
The extensive research projects stemmed from concerns in 2000 that trout were to be introduced into the Salt River in Nature's Valley for recreational fishing. Dr Ferdy de Moor of the Albany Museum said the macroinvertebrate fauna collected proved to be "so special" - recording 13 undescribed species as well as three possibly undescribed genera - that a permit for introducing this alien fish into the Salt River was denied.
On a request from the Nature's Valley Trust, a second study was undertaken in 2004, revealing a further three undescribed species. From this it was recommended that surveys of southern Cape rivers should be carried out to assess the status of indigenous invertebrate fauna in these rivers.
Over two years, between 2008 and 2010, teams set about studying 11 selected rivers in the Tsitsikamma mountains. From 616 samples collected during the survey of 20 river sites, 33 undescribed species were found. "The rivers were characterised by high numbers of taxa, and large populations of regionally endemic species," De Moor writes in an executive summary produced for SANParks and Cape Nature.
In one of the projects, Rhodes University zoology student Lyndall Pereira da Conceicoa studied a cold mountainous-adapted mayfly family (Ephemeroptera: Teloganodidae). He found that this family of mayfly was restricted to pristine mountain rivers in the western and southern Cape, with one genus outlier in Hogsback in the Eastern Cape.
"They are sensitive to disturbances and are not found downstream of any forms of anthropogenic developments or cultivated lands," said SANParks freshwater conservation expert Dirk Roux. "There are four genera in this family and each genus has only one described species that occurs from the Cederberg to Hogsback." Garden Route Media
By: John Harvey
Article Source: SUNDAY WEEKEND ARGUS