New Zealand Journal of Marine and Freshwater Research abstracts
Leaf litter characteristics affect colonisation by stream invertebrates and
growth of Olinga feredayi (Trichoptera: Conoesucidae)
JOHN M. QUINN
BRIAN J. SMITH
GREGORY P. BURRELL*
STEPHANIE M. PARKYN
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 11 115
Hamilton, New Zealand
email: j.quinn@niwa.cri.nz
*Present address: Zoology Department, University of
Canterbury, Private Bag 4800, Christchurch, New Zealand.
Abstract The influences of leaf characteristics on
stream invertebrate communities were investigated to improve the
basis for selecting plants for riparian management to enhance stream
invertebrate abundance and biodiversity. Invertebrate colonisation of leaves of
five native and five exotic riparian plants were compared over 4 months in
field experiments in a New Zealand pasture stream and adjacent channels,
and laboratory experiments were carried out on the leaf preferences and effects
on growth of the larvae of Olinga feredayi. Plastic strips and
leaves enhanced average invertebrate species richness on tiles in streamside
channels by 35 and 68%, and density by 50 and 140%, respectively, indicating
that both food and physical habitat contribute to leaf pack effects of
increased invertebrate abundance and species richness. Densities of total
invertebrates and collector-browsers on leaf packs after 15 days in the
streamside channels were positively correlated with leaf % leaching and
microbial respiration, and negatively correlated with leaf carbon : nitrogen
(C:N) ratio and toughness. Filter-feeding invertebrates showed opposite
relationships. Growth of O. feredayi larvae on conditioned leaves was
negatively correlated with initial leaf C:N ratio, and positively correlated
with colonisation preferences of larvae presented with a range of conditioned
leaves. These findings provide improved guidance as to which riparian plants to
select to optimise the benefits of litter inputs for stream invertebrates.
Keywords leaf litter; functional feeding groups; Olinga
feredayi; invertebrate growth; experimental streams
M99030
Received 26 May 1999; accepted 1 November 1999
PDF file of entire paper: medium quality (1261K); (scanned from paper original: notes about this process)
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