Fish effects on charophyte establishment in a shallow,eutrophic New Zealand lake |
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| Authors: | Mary D De Winton Aleki T Taumoepeau John S Clayton |
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| Institution: | 1. National Institute of Water and Atmospheric Research Limited , P.O. Box 11 115, Hamilton, New Zealand E-mail: m.dewinton@niwa.co.nz;2. National Institute of Water and Atmospheric Research Limited , P.O. Box 11 115, Hamilton, New Zealand |
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| Abstract: | Fish exclosures were deployed within shallow, eutrophic Lake Rotoroa, Hamilton, New Zealand to assess the influence of an alien‐dominated fish population on establishment by charophytes. Replicated mesh exclosures were placed at sites differing in wave exposure and received transplanted charophyte oospores and plants, with identical material placed outside. Charophyte establishment from oospores and plant biomass were greater inside exclosures compared with outside. Wave exposure did not depress germling response and the effect of fish exclosures on charophyte establishment was least apparent at the most exposed site. Exclosures did not have a statistically significant influence on the light climate, and epiphytic algal development was similar or higher inside the exclosures. However, sediment mobilisation was lower inside the exclosures. Results suggest that fish were primarily responsible for the poor performance of unprotected charophytes in Lake Rotoroa, with fish effects on plants operating via direct disturbance or grazing. |
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| Keywords: | charophytes oospores germlings biomanipulation alien fish |
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