New Zealand Journal of Marine and Freshwater Research abstracts
Detecting patterns in hyporheic community structure: does sampling method alter the story?
M. R. Scarsbrook
J. Halliday
National Institute of Water and Atmospheric
Research Limited
P.O. Box 11 115
Hamilton, New Zealand
email: m.scarsbrook@niwa.cri.nz
Abstract Hyporheic invertebrates were sampled in six small headwater streams draining pine, pasture, and native forest catchments. Sites were sampled in autumn and spring using three different hyporheic sampling methods (colonisation pots, pump sampling, and freeze-coring). Total invertebrate abundance and taxon richness differed significantly among sites on both sampling occasions for pump samples, whereas freeze-coring did not discriminate among sites, and pot samples showed significant differences in autumn, but not in spring. Differences among sites with respect to community composition were not consistent between sampling methods. Community ordination indicated that samples from colonisation pots tended to group together, whereas pump and freeze core samples were widely separated. Differences across land uses were also apparent (native forest sites formed a distinct cluster separated from pine and pasture sites). Results suggest that colonisation pots may provide a pathway for the entry of epigean organisms into the hyporheic zone even when hydraulic connectivity between surface and hyporheic zones is low. Invertebrate abundance was very low in pump samples, and this method also captured the fewest taxa of the three methods. The size bias known to exist with pump sampling techniques may restrict the usefulness of the method when comparing streams of differing hydraulic conductivity.
Keywords hyporheic zone; hyporheos; land use; sampling methods
M01018 Received 14 February 2001; accepted 15 October 2001
New Zealand Journal of Marine and Freshwater Research, 2002, Vol. 36: 443–453
0028–8330/02/3602–0443 $7.00 © The Royal Society of New Zealand 2002
PDF file of entire paper: Print-quality (164K)
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