Natural History

The Usambaras form part of the Eastern Arc Mountains, which run from north to south southwest from southern Kenya to southern Tanzania. The massifs are old, geologically speaking. They formed around a hundred million years ago rising along an ancient fault line. The massifs tower over the surrounding plains and as coastal rangesand they catch the Indian Ocean’s prevailing monsoon rains. Consistent seasonal rainfall, even during the Pleistocene, fostered tropical forest growth throughout the Eastern Arcs. Steep elevation and temperature gradients also fostered biologicalvarietyover very short distances, so much so that the scientific establishment considers the mountain forests to be global biological diversity hotspots withhigh conservation values.