New Zealand Journal of Marine and Freshwater Research abstracts
Land use effects on habitat, water quality, periphyton,
and benthic invertebrates in Waikato, New Zealand,
hill-country streams
JOHN M. QUINN
A. BRYCE COOPER
ROBERT J. DAVIES-COLLEY
J. CHRISTOPHER RUTHERFORD
R. BRUCE WILLIAMSON
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 11 115
Hamilton, New Zealand
Abstract Water quality, habitat, and biota were compared
during spring amongst c. 100 m reaches on 11 streams draining pasture, native
(podocarp-broadleaf) forest, and exotic pine forest established on pasture 15
years previously. Differences were greatest between the pasture and native
forest streams. Only 1-3% of incident light reached native and pine forest
streams whereas 30% reached pasture streams. Pasture streams had 2.2deg.C
higher mean temperature than the native streams, and 5-fold higher nitrate,
30-fold higher algal biomass, and 11-fold higher gross photosynthesis. Native
streams were 60% wider than pasture, with pine streams intermediate. Pine and
pasture streams had 3-fold higher suspended solids and fine sediment stored in
the streambed than native streams. Woody debris volume was 17-fold greater in
pine than pasture streams, with native streams intermediate. Invertebrate taxa
richness did not differ between land uses. Community composition differed most
between pasture and native forest, with pine forest streams intermediate.
Invertebrate densities were 3-fold higher in pasture than native streams,
mainly because of more chironomids and snails, but mayflies, stoneflies, and
caddisflies densities were 2-3-fold higher in forest streams than pasture.
Keywords channel morphology; riparian shade; water
temperature; nitrogen; suspended sediment; water clarity; coarse woody debris;
photosynthesis; benthic respiration; New Zealand
New Zealand Journal of Marine and Freshwater Research, 1997, Vol. 31:
579-597
0028-8330/97/3105-0579 $7.00/0 (c) The Royal Society of New Zealand
1997
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