New Zealand Journal of Marine and Freshwater Research abstracts
Comparing herbivory effects of stream macroinvertebrates on microalgal patch
structure and recovery
Joseph R. Holomuzki1,2
Rex L. Lowe2,3
Jennifer A. Ress3
1 Department of Evolution, Ecology, and Organismal Biology
The Ohio State University
1680 University Drive, Mansfield
OH 44906, United States
email: holomuzki.3@osu.edu
2 National Institute of Water and Atmospheric Research Limited
P.O. Box 8602
Christchurch, New Zealand
3 Department of Biological Sciences
Bowling Green State University
Bowling Green
OH 43403, United States
Abstract We studied short-term herbivory and recovery of
microalgal communities grazed by snails (Potamopyrgus antipodarum),
mayflies (Deleatidium spp.),
and caddisflies (Pycnocentrodes aeris) in microcosms containing low
algal food supplies characteristic of grazer-controlled streams. Herbivore
biomass was standardised across single-species treatments to assess grazing
effects owing to taxon-specific differences in feeding modalities. Potamopyrgus decreased
algal biovolumes, on average, by 56% in 4 days, and multidimensional scaling
(MDS) showed that snail-grazed microalgal communities were distinct. The erect
diatoms Synedra ulna and Staurosirella leptostauron were less
abundant, and basal cells of the chlorophyte Stigeoclonium lubricum were
more abundant, in snail-containing treatments than in ungrazed controls and
other species treatments. In contrast, more mobile caddisfly and mayfly larvae
failed to significantly alter algal biomass and assemblage, suggesting radular
mouthparts of snails were more effective at removing algae from the diatom-dominated
communities than the bladelike or brushing mouthparts of caddisflies and mayflies,
respectively. Microalgal communities recovered to pre-grazed conditions in
all treatments after 4 days in a grazer-free, outdoor flume. Diatoms also dominated
the recovery phase, but the erect forms S. ulna and S. leptostauron were
more abundant during recovery than grazing. Wilhm’s diversity decreased after recovery,
suggesting grazing had a positive effect on algal diversity. Thus, herbivory
primarily by Potamopyrgus affected microalgal patch structure, and hence
the starting successional sere, but had no detectable effect on short-term
successional direction in these fast-recovering communities.
Keywords microalgal biomass and diversity; herbivore traits;
algal community recovery; Potamopyrgus antipodarum; Deleatidium spp.; Pycnocentrodes
aeris
New Zealand Journal of Marine and Freshwater Research, 2006, Vol. 40:
357–367
0028–8330/06/4002–0357 © The Royal Society
of New Zealand 2006
M05039; Online publication date 12 May 2006. Received 28 June 2005;
accepted 13 December 2005
PDF file of entire paper: Print-quality (608K) |
screen-quality (351K)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
