“Invasive” Species

Photo by Michael A. Lewis


Our presently dominant culture is based on ever increasing consumption of “natural resources,” that is, water, soil, minerals, air, plants and animals, solely for human use. Ecologists tell us we are now consuming over 1.5 Earths per year, a process that is, by definition, unsustainable (not able to be maintained at the current rate or level).

In addition to killing individual plants and animals, human resource consumption results in habitat loss and thus the generation of species extinctions far beyond that which occurs naturally. Species extinctions leave great holes in the web of life that ripple outward through ecosystems for generations to come. Eventually a dynamic equilibrium is restored among the remaining species, ecological niches are filled and evolution continues.

In ecosystems suffering from growing human consumption, balance among species can never be restored, as member species continue to decline and disappear. In the absence of viable resident species, invasive species, which often have no natural predators or environmental limitations, take over abandoned niches and flourish, at the expense of other species.

Humans dominate ecosystems by overwhelming all other species, through extirpation and domestication. Rather than living within natural environmental cycles and limitations, humans modify or destroy natural habitats and the species that live within them, and replace them with human constructed habitat, exclusively for human use.

Looked at in this light, Homo sapiens is the ultimate invasive species.

Nature, however, always bats last, and humans are beginning to discover that our seemingly overwhelming environmental domination has cracks around the edges, cracks through which invasive species appear in human ecosystems, finding unfilled niches and creating consternation for those chiefly concerned with human control of their environments.

Coyotes move into urban neighbors where cats and small dogs provide a movable feast. “Weeds” (plants that grow where humans don’t want them to) fill in the margins of cultivated fields, take over disturbed habitat and generate their own mini-ecosystems.

Life always finds a way.

One might think that clever humans might find a way to live as resident species rather than invasive species, to thrive in place as cooperative members of the community of life in the ecosystems in which they reside.


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