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<p>Populations of <italic>Chaetogammarus ischnus</italic> and <italic>Pontogammarus robustoides</italic> living in the middle part of the Włocławek Dam Reservoir (on the lower Vistula River, central Poland) were studied. The two species coexisted at offshore sites of the reservoir, with <italic>P. robustoides</italic> being much more abundant than <italic>C. ischnus.</italic> In samples collected from the bare bottom of the reservoir (sandy or covered by zebra mussel shells) and macrophytes a negative relationship between the two species was observed: <italic>C. ischnus</italic> occurred in high numbers in those samples in which abundance of <italic>P. robustoides</italic> was low. This phenomenon is postulated as resulting from the larger size and more predatory nature of <italic>P. robustoides</italic>, limiting the occurrence of <italic>C. ischnus.</italic></p>
</abstract>

Populations of Chaetogammarus ischnus and Pontogammarus robustoides living in the middle part of the Włocławek Dam Reservoir (on the lower Vistula River, central Poland) were studied. The two species coexisted at offshore sites of the reservoir, with P. robustoides being much more abundant than C. ischnus. In samples collected from the bare bottom of the reservoir (sandy or covered by zebra mussel shells) and macrophytes a negative relationship between the two species was observed: C. ischnus occurred in high numbers in those samples in which abundance of P. robustoides was low. This phenomenon is postulated as resulting from the larger size and more predatory nature of P. robustoides, limiting the occurrence of C. ischnus.

Relationships between the occurrence of <italic>Chaetogammarus ischnus</italic> (Stebbing, 1898) and <italic>Pontogammarus robustoides</italic> (G. O. Sars, 1894) (Crustacea, Amphipoda) in a lowland Polish dam reservoir

Department of Hydrobiology Institute of Ecology and Environmental Protection

Department of Invertebrate Zoology Institute of General and Molecular Biology

Oceanological and Hydrobiological Studies

Relationships between the occurrence of  (Stebbing, 1898) and  (G. O. Sars, 1894) (Crustacea, Amphipoda) in a lowland Polish dam reservoir

Populations of Chaetogammarus ischnus and Pontogammarus robustoides living in the middle part of the Włocławek Dam Reservoir (on the lower Vistula River,...

Relationships between the occurrence of Chaetogammarus ischnus (Stebbing, 1898) and Pontogammarus robustoides (G. O. Sars, 1894) (Crustacea, Amphipoda) in a lowland Polish dam reservoir

Published Online: Jul 02, 2008

Page range: 39 - 50

DOI: https://doi.org/10.2478/v10009-007-0050-1

Keywords
gammarids, invasive species, intra-guild predation, competition, inter-specific interactions

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