Teaching the Complex Biological Problems of Wild Vertebrate Populations
The complex ecology of wild vertebrate species in ecosystems that man has altered is often misinterpreted through oversimplification. Environmental education must avoid the temptation to suggest perfect answers to complex environmental issues.
There is a high degree of innate stability and resilience of naturally evolved animal-plant-soil relationships of communities undisturbed by man. The lack of interspecific dependence amongst mammals and other vertebrates in natural temperate biomes is such that the effect on other vertebrates of even the removal of all individuals of some species, such as removing all of the deer in North America, remains almost unmeasurable to all but a few carnivores until their absence after several years causes physical changes in some of the habitats. However, when man modifies habitats, most vertebrates are affected deleteriously.
A fact often overlooked is that in spite of the unfortunate extinction of many animals during the past two centuries, today there are more kinds of animals present on all continents of the world than there were several hundred years ago. This is due to man creating new habitats and to the many introductions of wild and domestic animals and also escapes. Since habitat alteration is the main way the balance of nature is upset, habitat modification is usually an undesirable form of biological control of field vertebrate pests. Native predators also actually sustain a higher density of their prey species than would persist without such predation. And, surprisingly, there are far fewer vertebrate pest problems with monoculture than with diversified agriculture. Most cultivated plants in North America, for example, would not be able to survive as successful economic crops or as used in landscaping if all wild vertebrates had always been protected. These new genetic or exotic varieties have no evolved resistance to either the native browsing and grazing mammals or the feeding behavior of birds. The reverse is found in New Zealand, where the vegetation evolved in the absence of grazing and browsing mammals; hence many species of plants are easily destroyed by the introduced mammals.
KeywordsPrey Species Environmental Education European Rabbit Disturbed Environment Vertebrate Population
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