Dreissena polymorpha in Lake Constance: An example of a keystone engineer?
نویسندگان
چکیده
In the last decades, zebra mussels (Dreissena polymorpha) have invaded many freshwater systems with severe consequences for entire communities. Most benthic macroinvertebrates, especially amphipods and chironomids, increase in abundance in the presence of zebra mussels. Increased structural complexity and an unknown biotic factor lead to this effect. Dreissena-associated factors that might influence populations of the native Gammarus roeselii and the invader Dikerogammarus villosus in Lake Constance, Central Europe, were investigated in laboratory experiments. These factors were: 1) increased structural complexity related to mussel shells, 2) Dreissena biodeposition, 3) chironomids, the presence of which is increased by biodeposited matter, and 4) Dreissena kairomones. In habitat-choice experiments, the native and omnivorous amphipod G. roeselii showed a preference for mussel shells with biodeposited material and for mussel shells with biodeposited material and chironomids, whereas the invasive and predatory amphipod D. villosus showed a preference only for mussel shells with biodeposited material and chironomids. In a kairomone y-maze experiment, both amphipods avoided zebra-musselconditioned lake water. These results indicate that habitat complexity and food availability, mediated directly or indirectly through biodeposited material, are the II Zebra mussels affect amphipod species 10 factors by which amphipod abundances are increased in the presence of Dreissena. Thus, biodeposited material can form an important new food resource, translocated from the pelagic zone to the benthos by zebra mussel filtration, and this biodeposited material might support a new detritus-based food web in the benthos.
منابع مشابه
Gammarids in Lake Constance: habitat segregation between the invasive Dikerogammarus villosus and the indigenous Gammarus roeselii
Over the past decades the invasive Ponto-Caspian gammarid Dikerogammarus villosus spread throughout large rivers of central Europe, thereby rapidly displacing most of the native gammarid species. In 2003, D. villosus was fi rst observed in Lake Constance and was predicted to out-compete the native Gammarus roeselii. However, today the two species coexist at several sites. We hypothesized that a...
متن کاملEffects of zebra mussels on a native amphipod and the invasive Dikerogammarus villosus: the influence of biodeposition and structural complexity
In the last decades, zebra mussels (Dreissena polymorpha) have invaded many freshwater systems with severe consequences for entire communities. Most benthic macroinvertebrates, especially amphipods and chironomids, increase in abundance in the presence of zebra mussels. Increased structural complexity and an unknown biotic factor lead to this effect. Dreissena-associated factors that might infl...
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On July 13, 1992 a team of researchers from the BFS visited Kashong Bay in order to provide a characterization of the benthic community prior to expected impacts by the then recent introduction of the zebra mussel, Dreissena polymorpha (Harman, 1993a). A transect was erected perpendicular to the shoreline from the eulittoral zone (beach) to 25 feet in depth. Inspection by SCUBA was used to coll...
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