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Facilitation of native stream fauna by an invading species? Experimental investigations of the interaction of the snail, Potamopyrgus antipodarum (Hydrobiidae) with native benthic fauna
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posted on 2002-09-01, 00:00 authored by E S G Schreiber, P S Lake, Gerry QuinnGerry QuinnBiological invasions are regarded as a major threat to native ecosystems, yet studies investigating the interactions of invaders with native biota under field conditions are rare. Whilst many invaders are present only in low densities, it is often the effects of high densities that are of particular concern. We manipulated densities of the invading New Zealand aquatic snail Potamopyrgus antipodarum within an Australian stream to test the relationships between relatively high and low densities of the invading snail and other benthic fauna. Two experiments were carried out: the first experiment investigated the relationship between P. antipodarum and benthic fauna colonising within a short period of six days, the second looked at the effects after six days of high P. antipodarum densities on resident benthic fauna. In both experiments, there was no evidence of a negative relationship between densities of P. antipodarum and native fauna. On the contrary, both experiments showed a positive relationship between P. antipodarum densities and those of some common native fauna. In the second experiment invader densities were positively correlated with total number of native taxa, as well as with total densities and the densities of common invertebrates. Coprophagy is suggested as a possible mechanism by which increase in P. antipodarum could facilitate increase in native fauna. The results of this work strongly suggest that the effects of an invader can include indirect effects on the trophic dynamics of an ecosystem.
History
Journal
Biological invasionsVolume
4Issue
3Pagination
317 - 325Publisher
SpringerLocation
New York, N.Y.Publisher DOI
ISSN
1387-3547Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2002, Kluwer Academic PublishersUsage metrics
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