Biology Reference
In-Depth Information
Part III.
Evolutionary Interaction
of Aliens and Natives
Some of the most dramatic examples of rapid evolution as a consequence
of alien introductions involve species linked by food chain relationships.
These examples include evolutionary change by the alien species them-
selves, the native species with which they interact, or, in many cases, both
alien and native forms. In addition, various alien species brought together
in new geographic regions often exhibit evolutionary interactions.
In chapters 9, 10, and 11, we examine patterns of rapid evolution of
alien herbivores, predators, parasites, and disease agents to the new prey
and hosts they encounter. Often freed from their own enemies and
encountering prey or hosts lacking specific defenses, aliens may show
rapid evolutionary change. Successful alien species in turn may stimulate
evolutionary responses by natives. In chapters 12, 13, and 14, we turn our
attention to evolutionary changes by native species. These include the
ability of natives to exploit these species and to evolve ways to mitigate
the detrimental impacts of alien predators, parasites, and disease agents.
Finally, in chapter 15, we describe how alien plants and animals accu-
mulate herbivores, predators, and parasites from the new native biota that
they have entered.These patterns of accumulation represent the first step
toward ecological integration of the aliens.
These evolutionary interactions are the focus of some of the most
active current research. How these interactions play out on a global scale
will be the focus of part IV.
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