In contrast with the greater part of Portugal, the eucalyptus is relatively rare in the National Park. This is an important plus for the Park because the eucalyptus supports a much reduced diversity of animal life. This is because, as an exotic species (originating from Australia), the eucalyptus (Eucalyptus sp.) was never present for our fauna to evolve in a way to feed from its leaves or fruit (there are no indigenous Portuguese species that eat eucalyptus leaves, bark or fruit). Another reason for the low biodiversity associated with the eucalyptus is linked to the short cutting cycle which usually implies destruction of undergrowth and bushes. Even so gorse, heather and grasses can sometimes be found beneath the trees.