Densities in the Wild

If we can really understand the problem, the answer will come out of it, because the answer is not 

In the wild, there is a natural population carrying capacity for an area. When food, nesting sites, materials, or other essentials become scarce, reproduction slows or ceases, disease incidence increases, or weakened individuals are caught and eaten by predators. Thus, there seem to be mechanisms for the regulation of stable population sizes. Crowding upsets at least some of these mechanisms. 

As animals grow from childhood to maturity, they may migrate from their family units to find their own territories where others of the same species do not live. If there are others in the new region, competition for that space can become fierce. Eventually, the natural density of animals reaches a sustainable value. 

For plants, too, there is a population density limit. For many plants in temperate climates, the maximum density is determined by access to light. Overcrowded plants tend to be tall and spindly, with small leaves. These plants have poor chances to survive additional environmental insults such as drought or insects (see Section 7.6.3). 

In desert areas, water is often the limiting resource, and tlie greater distance between plants results from water nonavailability. Attempting to grow desert plants at greater densities than this will result in the death of many of them. 

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