The mountains of East Africa are a treasure trove of biodiversity. However, their ecosystems may be at a higher risk than previously realized. Dr. Andreas Hemp and Dr. Claudia Hemp have discovered that Mount Kilimanjaro is turning into an "ecological island". Agriculture and housing construction have eliminated the natural vegetation that used to serve as a bridge to the surrounding area, enabling the diversity of species to develop to its current levels. Neighbouring mountain regions are presumably also being isolated from their surrounding areas. The researchers have published their study in the journal Global Change Biology.
With a height of almost 6,000 metres, Mount Kilimanjaro is the highest mountain in Africa, and it is located less than 100 kilometres from the 4,600-metre-high volcano Mount Meru in northern Tanzania. Satellite images show how the strips of land between them changed in the 25 years leading up to the turn of the century. Areas that originally had dense vegetation were forced to make room for the intensive agriculture and residential development of a growing population. Nowadays, Mount Kilimanjaro is almost completely surrounded by large areas that are characterized by the encroachment of human civilization.
Bridges of vegetation promote the diversity of species
In order to investigate the impact this rapid change is having on biodiversity, the biologists from the University of Bayreuth and the Biodiversity and Climate Research Centre Frankfurt (BiK-F) studied the environments of grasshoppers at 500 selected sites on Mount Kilimanjaro and Mount Meru. In this investigation, endemic species – species that are only native to this region of East Africa – were of particular interest. The scientists found an especially high proportion of endemic species in the forest areas at lower altitudes shared by these two mountains. This is a clear indication that grasshoppers once used the dense vegetation between the mountains as bridges to spread out in both regions. Most notably, the flightless species relied on this land route.
Read more at University of Bayreuth
Image: Much of the natural forest vegetation between Mount Meru and Mount Kilimanjaro vanished between 1976 and 2000. (Illustrations: Andreas Hemp)