New Zealand Journal of Marine and Freshwater Research abstracts
Development of standard protocols for macroinvertebrate assessment of
soft-bottomed streams in New Zealand
John R. Maxted
Brent F. Evans
Auckland Regional Council
21 Pitt Street
Auckland, New Zealand
email: john.maxted@arc.govt.nz
email: brent.evans@arc.govt.nz
Mike R. Scarsbrook
National Institute of Water and Atmospheric
Research Limited
P.O. Box 11 115
Hamilton, New Zealand
email: m.scarsbrook@niwa.co.nz
Abstract Macroinvertebrate communities in hard-bottomed
(HB) and soft-bottomed (SB) streams were compared to address questions on
sample substrata, sample area, and data interpretation. Communities at HB
and SB reference sites (native bush catchments) were distinctly different.
SB reference sites had 50% of the total taxa, 33% of the Ephemeroptera, Plecoptera,
and Trichoptera (EPT) taxa, and significantly lower Macroinvertebrate Community
Index (MCI) and Semi-Quantitative MCI (SQMCI) scores than HB reference sites.
Ten EPT genera were abundant (>20 individuals per sample) at HB reference
sites compared with one EPT genus (Zephlebia) at SB reference sites. The
densities of macroinvertebrates at SB reference sites were <10% of those
at HB sites indicating the need to sample a larger area to obtain a representative
sample. SB sites with severe urban and rural land use disturbance had significantly
lower metric values than SB reference sites. The SQMCI was the only metric
sensitive to moderate disturbance, and multivariate ordination further supported
the value of relative abundance data in detecting moderate impairment in
SB streams. Hand sampling of submerged wood added 16-40% more taxa in total,
and 11-44% more EPT taxa to sweep-net samples, indicating the importance
of directly sampling wood in SB streams. The results supported separate collection
methods and data interpretations for HB and SB streams proposed in recently
published New Zealand protocols.
Keywords macroinvertebrates; methods; metrics; community
composition; reference conditions; sensitivity; submerged wood; woody debris;
New Zealand
M02103 Received 23 December 2002; accepted 1 August 2003; Online publication
date 31 October 2003
New Zealand Journal of Marine and Freshwater Research, 2003, Vol. 37:
793-807
0028-8330/03/3704-0793 $7.00 © The Royal Society of New Zealand
2003
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