Cities depend on nature, we are inside nature (Earth) and we are a part of nature and the great cities that we build, thrive or die because of the natural world around them.
Magazine article
migration watch
graphs and quotes
ancient woodlands and wilderness destruction for more urbanizing.
When crowding becomes too great after population buildups, interactions intensify, leading to greater and greater stress. As psychological and emotional stress builds up and tempers wear thin, subtle but powerful changes occur in the chemistry of the body. Births drop while deaths progressively increase until as state known as ‘population collapse’ occurs. Such cycles of build-up and collapse are now generally recognized as normal for the warm-blooded vertebrates and possibly for all life. Contrary to popular belief, the food supply is only indirectly involved in these cycles.
The adrenals play an important part in the regulation of growth, reproduction and the level of the body’s defenses. The size and weight of these important glands is not fixed but responds to stress. When animals are too frequently stressed, the adrenals, in order to meet the emergency, become overactive and enlarged…Mortality [in major animal die-offs that were extensively studied by John Christian] evidently results from shock following severe metabolic disturbance, probably as a result of prolonged adrenocortical hyperactivity. There is no evidence of infection, starvation, or other obvious cause to explain the mass mortality.
It is now widely held that the processes of selection which control evolution favor the dominant individuals in any given group. Not only are they under less stress but they also seem able to stand more stress. The adrenals work harder and become more enlarged in subordinate animals…A blowup of aggressiveness and sexual activity and accompanying stresses overload the adrenals. The result is a population collapse due to lowering of the fertility rate, increased susceptibility to disease, and mass mortality from hypoglycemic shock. The dominant animals, however, usually survive. – Edward Hall