New Zealand Journal of Marine and Freshwater Research abstracts
Comparison of fish and macroinvertebrate standing stocks in relation to
riparian willows (Salix spp.) in three New Zealand streams
GORDON J. GLOVA
PAUL M. SAGAR
NIWA Marine
National Institute of Water and Atmosphere
P. O. Box 8602, Riccarton
Christchurch, New Zealand
Abstract The distribution of fish and benthic invertebrates
in relation to riparian willow (
Salix spp.) concentrations was
investigated in three New Zealand streams. In each of the streams,
representative sites were sampled quantitatively in willowed and non-willowed
sections. The abundance (m
-2) and biomass (g m
-2) of
brown trout (
Salmo trutta L.) were significantly greater in the willowed
than in the non-willowed sections in two streams; the third stream showed the
same trend but any differences were not significant. Mean size of trout was
greater in the willowed than in the non-willowed sections, but size of fish
varied greatly and the differences were not significant. Eels (
Anguilla
spp.) showed no consistent pattern in population characteristics between
streams; however, their abundance in one river and biomass in another were
significantly greater in the willowed than in the non-willowed sections.
Distribution of other fish (e.g.,
Galaxias spp. and
Gobiomorphus
spp.) appeared not related to riparian willows. The abundance and biomass of
several benthic invertebrate taxa (e.g., Ephemeroptera, Trichoptera, Diptera)
differed significantly in relation to riparian willow concentrations. In all
three streams, species richness and diversity of the benthic invertebrates were
greater in the willowed than the non-willowed sections, with moderate degrees
of similarity between the communities. Moderately-willowed riparian zones are
beneficial to trout and food organisms in streams and small rivers.
Keywords riparian willows (Salix spp.); brown trout;
native fishes; benthic invertebrates; abundance; biomass; standing stock
New Zealand Journal of Marine and Freshwater Research, 1994: Vol. 28:
255-266
0028-8330/94/2803-0255 $2.50/0 (c) The Royal Society of New Zealand
1994
PDF file of entire paper: medium quality (1365K); (scanned from paper original: notes about this process)
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