Environmental Engineering Reference
In-Depth Information
Unfortunately, but not surprisingly, ecosystem controls can be highly varied and complex.
Weathers et al. remind us that ecosystems may be controlled both by abiotic factors and
biotic factors. Especially in the last few centuries, human controls have become important
in many ecosystems. Control can come from inside or outside the ecosystem, and from
the bottom of the food web or the top. Weathers et al. suggest that feedbacks within the
ecosystem are nearly always important. The mathematical relationships between the
controlling variable and the ecosystem can be of many kinds, including thresholds and
poorly reversible relationships with which it may be difficult for environmental managers
to deal with.
