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21 Phytosanitary Measures to Prevent
the Introduction of Invasive Species
Guy J. Hallman
21.1 Introduction
Regulatory animal and plant protection strives to safeguard agricultural
species from pests, diseases, and competition from foreign non-beneficial
species. The traditional concern for protecting only economic species (crops,
livestock, grazing lands) has recently been broadened to include endangered
native species and ecosystems in general, upon the acceptance that ecosystems
other than agricultural also provide tangible economic benefits to
humanity (Perrings et al. 2000), not to mention what are considered the
more intangible benefits arising from our innate affinity with nature (Wilson
1984).
The problem with invasive species is as critical now as it has ever been. It
could be argued that regulatory animal and plant protection has not done a
good job at protecting economic species, let alone performing its more recent
task of protecting ecosystems. Still, that apparent failure in the prevention of
invasive species must be measured in light of the magnitude of the ever
increasing problem, the modest amount of resources directed toward it, and
educated guesses about what shape the world would be in without regulatory
protections.
Changes in climate, habitats, soil nitrogen levels, atmospheric carbon dioxide
levels, trade, and travel make the job of regulating potential invasive
species more difficult (Schwalbe and Hallman 2002). Changes in global climates
may exacerbate problems with invasive species by more than simply
making temperatures more amenable to the survival of organisms from
warmer climates (Chap. 12). Parker et al. (2006) argue that invasive “meltdown”
occurs when exotic herbivores replace native ones that were better at
controlling invasive plants. In essence, exotic invasive plants thrive not by
escaping their natural herbivores but by following them. Atmospheric turbulence
from hurricanes in Florida in 2005, the increased intensity of which is
Ecological Studies,Vol. 193
W. Nentwig (Ed.)
Biological Invasions
© Springer-Verlag Berlin Heidelberg 2007