Biological Disasters
...ined are isolated from others, which disrupts cycles and ultimately the plants and animals die out. Many animals don't even cross a road separating forests and therefore upset the food chain if their prey does so. Introduction of alien species: This form of destruction doesn't always involve direct human interference. Once an alien species has been introduced in an area with good conditions for its own survival it can cause devastating results to the biodiversity of that vicinity. a) The introduced species may start feeding on any native species that can't defend itself. A good example for this is a large African killer snail which was supposed to reduce the number of one of the native Hawaiian snails, didn't though as it preferred another slightly smaller and less highly populated native Hawaiian snail. This and many other threats engaged on Hawaii have impoverished its biodiversity today. b) They breed out of control unless there are natural checks and balances. The outcome could be that they may eat more than the native vegetation can supply, and as the vegetation is usually the backbone of an ecosystem the entire food chain could collapse. c) Introduced species may struggle f...