Slide 16: Example of how direct/indirect variables may affect a plant species
Indirect and direct variables interact with a species in a number of ways. Indirect variables such as geology or topology determine the state of variables through their interaction. These direct variables (temperature, rainfall, soils, etc) likewise interact with each other and a plant through the actions of combined resource variables. A plant can also change the resource variables to some extent through feedback processes as a result of their growth, development and distributions. Finally, stochastic negative processes (one-off events like rockslides, floods, fires, and the like) will obviously affect plant distributions, and consequently affect the feedback processes to resources as well.