Biology Reference
In-Depth Information
Argentine ant, also are exerting severe pressures on native arthropods of
many sorts (Cole et al. 1992).
Insular aquatic environments are also likely to experience extinctions
due to introduced predators. Many native species of fish have become
extinct due to the impacts of alien fish invaders or introductions (Miller
et al. 1989). In North America, 27 species and 13 subspecies of fish have
become extinct over the past 115 yr. Direct impacts of alien fish con-
tributed to about 68% of these extinctions. Predation by species such as
the sea lamprey (
Petromyzon marinus
) and largemouth bass (
Micropterus
salmoides
) were implicated in the extinction of several species. In at least
one case, that of the landlocked Miller Lake lamprey (
Lampetra minima
) in
Klamath County, Oregon, extinction was an indirect effect of the intro-
duction of alien fish.The species was deliberately poisoned because it par-
asitized trout introduced to the lake.
Predatory fish of several species have been introduced to lakes
throughout the world in the name of improved sportfishing. In North
America, for example, these introductions have reduced or extirpated
native populations of many amphibians (Hecnar and M'Closkey 1997)
and minnows of the family Cyprinidae (Whittier et al. 1997). Similar
effects have been noted in Europe (Brönmark and Edenhamn 1994).
Mosquitofish (
Gambusia affinis
and related species) have been introduced
widely for the biological control of mosquitoes. In California (Gamradt
and Kats 1996) and Australia (Komack and Crossland 2000), they have
contributed to the decline of native amphibians by predation on eggs and
larvae. On Oahu, Hawaii,
Gambusia affinis
and
Poecilia reticulata
, members
of the same fish family, have caused the extirpation of native damselflies
in streams to which these fish have been introduced (Englund 1999).
Alien crayfish also prey on native amphibian larvae in California (Gam-
radt et al. 1997).
Some amphibians can be serious predators when introduced outside
their native range. Bullfrogs (
Rana catesbeiana
), as well as other ranid frogs,
have been introduced to various parts of western North America. These
introductions have contributed to the extirpation or endangerment of
several fish, amphibians, and reptiles (Cox 1999). In Australia, the cane
toad (
Bufo marinus
), introduced in 1935 for biological control, is of con-
cern because of its toxicity to native amphibians and fish that prey on its
eggs, tadpoles, and young (Crossland and Alford 1998).
The introduction of the Nile perch (
Lates nilotica
) to Lake Victoria,
East Africa, in the 1950s has probably had a greater impact than any other
single species introduction to an aquatic ecosystem. Lake Victoria had an
