Mineral Supply

Ascertaining the of the role/function of Mt Elgon’s elephants in supplying essential minerals for the ecosystem will answer the question if their presence on Mount Elgon is a key prerequisite for the existence of other species and if a loss of this population can have unpredictable consequences on the Mount Elgon ecosystem. It will also contribute to determine the cause of for their unique underground mining behaviour.

Eating of soils (geophagy) has been documented for elephants and several other herbivores on Mt Elgon. The mostly presumed cause is the compensation of mineral deficits in the herbal diet. In mountainous areas with high levels of rainfall, leaching often lead to low-mineral soils causing low mineral contents in the vegetation, growing on it. Mount Elgon is the oldest volcano of the Great African Rift Valley. Since its last eruption, about two million years ago, heavy rainfalls are leaching the soils on the mountain. This suggests the vegetation on Elgon can not cover the herbivores mineral requirements. The suggestion is confirmed by the fact, that the elephants have dug the caves under old lava coats, which are the only places on the mountain, where soils have been sheltered from leaching.

Within the underground salt-licks, increased concentrations of different minerals have already been measured. The, so far most extensive survey by Bowell et al. (2006) measured increased element concentrations and a geochemical enrichment of certain elements in Kitum Cave.

By quantitative elemental analysis of herbal diet of elephants as well as of other herbivores on Mt Elgon, we will identify potential nutritive deficiencies. If critical nutritive deficiencies can be identified and in the ecosystem sufficient quantities of the corresponding minerals only occur in the underground salt-licks, the elephants occupy a key role in supplying essential minerals for the Elgon ecosystem. With their tusks, elephants are the only animals with a suitable tool for breaking rocks out of the cave walls (see picture above). Their extinction would imply the cease of this essential minerals source and therefore imperil the survival of other animals on the mountain.

A successful resettlement of elephants from other areas is highly unlikely. Without good reason, elephants do not enter deep, dark caves and without the knowledge about the underground salt-licks they barely will find them.