New Zealand Journal of Marine and Freshwater Research abstracts
Microform bed clusters as refugia for periphyton in a flood-prone headwater
stream
S. N. FRANCOEUR1,2,3*
B. J. F. BIGGS2,3
R. L. LOWE1,3
1Department of Biological Sciences
Bowling Green State University
Bowling Green, OH 43403
United States
2National Institute of Water & Atmospheric
Research Ltd
P. O. Box 8602
Christchurch, New Zealand
3The University of Michigan Biological Station
Pellston, MI 49769
United States
* Present address: Department of Biological Sciences, University of Alabama,
Tuscaloosa, AL 35487-0344, United States. email: sfrancoe@biology.as.ua.edu
Abstract Flood effects on benthic algal communities grown
upon three common substratum types were assessed in a gravel-bed stream.
Microform bed clusters (MBCs) and, to a lesser extent, boulders conferred
resistance on their associated periphyton communities (i.e., reduced
flood-induced biomass loss; functioned as refugia) relative to cobble/gravel
substrata. On all substrata, flooding significantly reduced the relative
abundance of Diatoma hiemale, and increased the relative
abundance of Gomphonema minutum f. syriacum and/or
Ampithrix sp. Long-term (>4 months) sampling indicated that MBCs
generally supported more algal biomass than did boulders, which, in turn,
supported greater biomass than cobbles/gravels. Manipulation of the abundance
of refugial structures (e.g., MBCs) could possibly alter productivity of
flood-prone gravel-bed streams. Stream periphyton biomass models may be
improved by explicit consideration of the effects of refugial substrata. The
interstitial spaces of MBCs may constitute a unique habitat, and deserve
further study.
Keywords periphyton; benthic algae; disturbance; flood;
refugia; patch; resistance; resilience
M97048
Received 4 September 1997; accepted 9 April 1998
PDF file of entire paper: medium quality (936K); (scanned from paper original: notes about this process)
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