Carla d'Antonio from University of California in Berkeley and my colleague, Peter Vitousek, from Stanford University put forth a model about what's happening in many parts of the world. This model is quite general. When native woody vegetation is cleared, we get invasions of alien grasses and fire frequency increases. You then get into the situation where the woody vegetation can no longer predominate. So we're getting an enormous shift of the major biotic types through the introduction of invasive species. You see this happening in Hawaii and in the Great Basin with cheat grass, as I discussed earlier. You see it here in the southeast of the United States. Long leaf pine forests have a diverse under-storey. In recent years, a new grass from the tropics has invaded and is changing the fire cycle and will eventually, in the not too distant future, do away with this forest type.
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Narrative Index
BioForum Index
