New Zealand Journal of Marine and Freshwater Research abstracts
Leaf breakdown and colonisation by invertebrates in a headwater stream:
comparisons of native and introduced tree species
S. M. PARKYN*
M. J. WINTERBOURN
Department of Zoology
University of Canterbury
Private Bag 4800
Christchurch, New Zealand
*Present address: National Institute of Water & Atmospheric
Research Ltd, P. O. Box 11 115, Hamilton, New Zealand.
Abstract Leaf breakdown, colonisation by invertebrates, food
choice by a facultative shredder, and composition and activity of the
microflora of leaves of three native and three introduced trees were
investigated in a small headwater stream, South Island, New Zealand. Leaves of
each species were immersed and collected after 1, 32, 60, and 95 days to
measure mass loss and invertebrate colonisation. Additional leaves collected
after 60 days were used for food choice and respiration experiments, and others
taken after 95 days (some species) were examined with scanning electron
microscopy. Leaf breakdown rates followed the sequence: elm > red beech >
willow > mahoe > oak > mountain beech. Elm (introduced) and mahoe
(native) supported the highest invertebrate densities, but shredders were most
abundant on willow (introduced) and red beech (native) leaves. In laboratory
choice trials the facultative shredder Olinga jeanae showed a preference
for elm and red beech leaves which were fastest to break down and had high
respiration rates. We found that leaves of introduced trees can be preferred by
shredders and hence, no strong associations were apparent between shredders and
these native trees.
Keywords leaf breakdown; invertebrate colonisation; food
choice; shredders; respiration; microflora
New Zealand Journal of Marine and Freshwater Research, 1997, Vol. 31:
301-312
0028-8330/97/3103-0301 $7.00/0 (c) The Royal Society of New Zealand
1997
PDF file of entire paper: medium quality (2002K); (scanned from paper original: notes about this process)
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