The interplay of herbivores, grass and trees

Dr Ezio Venturino from the University of Turin will present the Department of Biological Science seminar with a talk entitled, "The interplay of herbivores, grass and trees".

Models for wild parks management have to take into account the grazing of pastures by herbivores and the possible threats that the phenomenon of debarking poses to forests. When the primary resource, represented by grass, becomes scarce during the winter season, the herbivores tend to feed themselves by peeling off the bark of the trees. This causes the breaking of the communications from the roots to the leaves, causing problems to the trees. They suffer because the leaves do not receive the necessary nutrients for producing chlorophyll. In the long term, the trees are bound to die. We compare the findings on a city park, in which sheep have been introduced to control the grass growth, with the situation in a few wild mountain parks. Examining carefully the interactions, it is found that in some cases the forests are at risk, while in some other ones the herbivores are in a delicate situation. Although at present herbivores in the wild are not endangered, should the climatic or environmental conditions change or be perturbed, there could be a serious threat for these populations which might lead to their disappearance. This extinction threat may be even more pronounced if natural predators, that here are not considered, are taken into account, although the model does not account also for possible herbivores migrations into neighboring wild areas in the bordering countries Austria and Slovenia.


Wed, 20 Sep 2017 - 12:00

M111, Mathematics Building, University Avenue, Upper Campus, UCT