Introduction

Farmers who keep grazing or browsing animals, such as cattle, sheep or goats, are familiar with the negative impact that herbivores can have on vegetation. Severe overgrazing can result in the destruction of vegetation cover and acute soil erosion. More subtle overgrazing can lead to a switch from a dominance of "sweet" (palatable) plants to a dominance of "sour" (unpalatable) plants, and therefore a reduction in stock productivity. Once unpalatable plants take over the veld, it is very difficult to restore the original condition of the pasture. Similar effects of herbivores are of considerable ecological and evolutionary importance to plants in natural communities. However, in natural communities, the effects of herbivores can rarely be though of as positive or negative, except when considered from a purely human perspective, or when the effects of herbivores exacerbate some negative human influence on an ecosystem. This WWW resource examines some of the effects of herbivores within the ecosystems in which they occur.

Severe overgrazing can result in the destruction of vegetation cover and acute soil erosion, as has happened here in the Transkei region of South Africa.

If you are reading this, you are probably a person who likes to spend time with nature. The purpose of this WWW resource is to present some of the concepts of herbivore-plant interactions using a variety of environments, so that you will be able look for evidence of some of these interactions, whether driving or walking in a game park, a forest, a field, on the seashore, or even in your own back yard. I hope that this resource will also be of use to biology students, either at secondary school or university.

If you have any feedback to offer, you may e-mail me and I will try to incorporate your suggestions, but please don't expect a response (if I responded to all the e-mail I receive, I would have no time to develop interesting web resources like this one). If you feel you can make a contribution to this web resource, or other educational resources on this server, please e-mail me with a proposal. If we like it, we will publish it, and include a link to your own page should you wish it.