The May 13, 2013 post presented a typical "range of tolerance" diagram that attempts to explain the way that different species thrive along specific portions of an environmental gradient.

In Nature (real life), of course, there are many environmental gradients (or factors). In Gardening: An Ecological Approach, I have added the logical extension to the explanation by adding more environmental factors. Now a landscape of "species nodes" begins to appear. One is depicted in the lower portion of the illustration from the book.

The impression for me is that there are many unique combinations of intersecting environmental gradients, each with a species thriving under those conditions.

Range of tolerance. © 2013 Fred Montague — Range of tolerance. © 2013 Fred Montague

In all of my teaching, one of the most important ecological concepts I believe that I shared with students is the concept that a population of organisms lives within a fairly specific range of environmental conditions.

The illustration below is a page from my wildlife textbook Wa-Maka-Skan. It is a simplified depiction that shows the general theoretical concept for one environmental factor. The bottom portion shows that for various fish species, one of the important environmental factors affecting their distribution and survival is water temperature.

This concept is relevant today, especially as human-caused global change alters the living conditions of species. Environments are shifted out from under the adaptations of the species. The faster the change and the larger the animal, the more problematic the situation becomes.

Range of Tolerance from Wa-Maka-Skan. © Fred Montague — Range of Tolerance from *Wa-Maka-Skan*. © Fred Montague

Nullam id dolor elit

Integer posuere erat