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The Lake Ontario zooplankton community before (1987-1991) and after (2001-2005) invasion-induced ecosystem change

Journal of Great Lakes Research

By:
, , , ,
DOI: 10.1016/j.jglr.2010.07.010

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Abstract

We assessed changes in Lake Ontario zooplankton biomass, production, and community composition before (1987–1991) and after (2001–2005) invasion-induced ecosystem changes. The ecosystem changes were associated with establishment of invasive dreissenid mussels and invasive predatory cladocerans (Bythotrephes and Cercopagis). Whole-lake total epilimnetic plus metalimnetic zooplankton production declined by approximately half from 42.45 (g dry wt∙m−2∙ year−1) during 1987–1991 to 21.91 (g dry wt∙m−2∙ year−1) in 2003 and averaged 21.01 (g dry wt∙m−2∙ year−1) during 2001–2005. Analysis of two independent data sets indicates that the mean biomass and biomass proportion of cyclopoid copepods declined while the same measures increased for the invasive predatory cladocerans. Changes in means and proportions of all other zooplankton groups were not consistent between the data sets. Cyclopoid copepod biomass and production declined by factors ranging from 3.6 to 5.7. Invasive predatory cladoceran biomass averaged from 5.0% to 8.0% of the total zooplankton biomass. The zooplankton community was otherwise resilient to the invasion-induced disruption as zooplankton species richness and diversity were unaffected. Zooplankton production was likely reduced by declines in primary productivity but may have declined further due to increased predation by alewives and invasive predatory cladocerans. Shifts in zooplankton community structure were consistent with increased predation pressure on cyclopoid copepods by alewives and invasive predatory cladocerans. Predicted declines in the proportion of small cladocerans were not evident. This study represents the first direct comparison of changes in Lake Ontario zooplankton production before and after the invasion-induced disruption and will be important to food web-scale investigations of invasion effects.

Geospatial Extents

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The Lake Ontario zooplankton community before (1987-1991) and after (2001-2005) invasion-induced ecosystem change
Series title:
Journal of Great Lakes Research
DOI:
10.1016/j.jglr.2010.07.010
Volume
36
Issue:
4
Year Published:
2010
Language:
English
Publisher:
Elsevier
Publisher location:
Amsterdam, Netherlands
Contributing office(s):
Great Lakes Science Center
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
596
Last page:
605
Other Geospatial:
Lake Ontario