Animal modification of native vegetation: The effects of insects on natural vegetation
- Entomology Division, Department of Scientific and Industrial Research, Nelson
There is a need for a greater awareness of the part which insects play in the determination of the pattern of natural vegetation. While the role of insects as plant pollinators is well known and accepted, ecologists in fields other than entomology have shown little interest in other aspects of insect modification of plant cover. This is reflected in the virtual absence from all the standard texts on plant ecology of discussion on effects caused by insects. While techniques have been developed to determine the roles of larger herbivores and rodents in the modification of vegetation, plant ecologists have no techniques for assessing the effect of the much more selective grazers among the insects (Huffaker 1962). This lack of understanding on the part of plant ecologists continues even though entomologists have clearly demonstrated some of the profound effects which insects can produce on vegetation by numerous successful projects for the biological control of weeds throughout the world. The role of insects in the modification of natural vegetation is much more clearly recognised in the field of forestry than in agriculture. It may be that the need for conservation of natural vegetation is a more firmly established principle in forestry where growth of useful species is often measured in terms of hundreds of years.