We love nature, but we must also take the trouble to understand the nature we love.
by Robert D. Hinkle, PhD.
November 2009
There are many well-meaning individuals from all walks of life who look at nature today and, with just concern, feel for the safety and well-being of every living thing existing there. They ask: why not save every wild creature? While the biology is old and the explanation is simple, the fact remains that a given habitat can adequately support only a certain number of individuals of a given species—a population—over time. A habitat is made up of many different populations of living things: plants, nematodes, insects, snails, earthworms, birds, mammals, and thousands of others living in that same area.
Most wild species reproduce in numbers far larger than their habitats can support. Nature ensures adaptation over time through natural selection acting upon individuals in each population. Survivors—the most fit, or sometimes simply the most fortunate in a given year—live to contribute whatever genetic traits helped them survive. Individuals beyond the ability of the habitat to support them will die, by fang or claw or by many other causes.
Generally, the highest mortality is caused by lack of quality food, lack of protective cover, or fatal exposure to heat, cold, or too much or too little rainfall or snowfall. Many other factors come into play as well. Populations with higher densities may decline through disease and the ease with which it spreads among closely packed individuals. Like it or not, that seems to be the way the natural world works.
Largely, the size and quality of habitats determine individual and population survival, and high-quality habitats ensure larger populations of healthy, vibrant individuals. Populations get into trouble when they are depleted beyond their ability to recover, or when habitats change and the land can no longer support them. Unexpected events such as disease outbreaks or competition from introduced species can also disrupt native populations.
Our difficulty with all this lies in our human perception of the value of life and our discomfort with death. In modern Western society we are taught to believe in the inherent value of each human individual. In the field, however, nature is not concerned with the survival of individuals. Instead, it is concerned with how individuals contribute to the long-term survival of the population.
It is the survival of species over time—not the survival of each individual—that matters in nature. Humans succeed outside many of these limits only because we have learned to modify our habitats to our advantage—providing food, shelter, water, and safety—and thereby expanding our populations beyond what the earth might naturally support. Most of us recognize that there are limits to this as well.
In the end, we love nature, but we must also take the trouble to understand the nature we love. Trying to overlay human attitudes and values on a complex web of interdependent species and the biogeochemistry of the land that supports them is, I believe, a fool’s errand. Nature plays by its own rules, and we have only just begun to translate the first sentence in that long and complicated book.
Good luck with that.