| Resumo: |
Vast areas of Brazil are being planted to Eucalyptus in order to provide renewable sources of timber, charcoal and cellulose. Although the rapid growth and productivity of various Eucalyptus species undoubtedly relaxes the pressure on logging of native forests, there are ecological costs. Firstly, some eucalypt species are vulnerable to pest outbreaks. A large number of native Lepidoptera, Coleoptera and leaf-cutting ants (Atta spp.), some of which have become pests, have been found on eucalypts growing in Brazil. Probably, the diverse myrtaceous flora of South America supports a fauna that can adapt to the introduced Eucalyptus species. Secondly, the leaf litter produced under Eucalyptus plantations differs substantially from that of native forests both in terms of its physical structure and chemistry, posing a range of problems for the native decomposer fauna. If microarthropod diversity is reduced, nutrient cycling could be impeded under eucalypt plantations. Thirdly, native forest canopies support a massive diversity and biomass of arthropods on which many birds, reptiles and mammals depend for food. The evidence is that invertebrate biomass and diversity are greatly reduced in the canopies of exotic eucalypt plantations. This, in turn, reduces the food-base on which forest arthropods and other animals depend, and hence their conservation status. This paper reviews the evidence for adverse ecological effects in Brazilian eucalypt plantations and suggests ways in which Brazil might meet its forestry needs, while conserving forest invertebrates and the vertebrates that depend on them.
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