Environmental Engineering Reference
In-Depth Information
(a)
Hyperpredation
Time
Control
(b)
Mesopredator release
Time
Control
(c)
Competitor release
Control
Time
Fig. 15.1
Three examples of how the overlooked presence of other invasive
species can hinder the success of a control programme aimed at protecting a local
species. (a) The hyperpredation process hinders the control of the predator (here
a cat, to use an example from the main text), as alien alternative prey (rabbits) are
abundant which boosts the predator's population growth rate, thereby precluding
full protection of the local prey (parakeet). (b) A mesopredator release may
occur if the superpredator (cat) is removed, with the result that the shared prey
(seabird) that was to be protected can be lost by a demographic explosion of the
mesopredator (rats). (c) A competitor release is here equivalent to mesopredator
release as the shared prey (lizard) may also be eliminated by a poorly-designed
control protocol resulting in an explosion of a lower competitor population
(mouse) as the higher competitor (rat) is eliminated.
