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Presented at the NABS Annual meeting, Athens, Georgia, 2003
in Landscapes
Factors determining the biodiversity of stream communities across an Arctic landscape
A.D. Huryn1, K.A. Slavik2, R.L. Lowe3, and D.S. Anderson1. 1Department of Biological Sciences, University of Maine, Orono, ME 04469-5722, 2The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543. , 3Biology Department, Bowling Green University, Bowling Green, OH 43403
We surveyed the macroinvertebrates of 32 streams in arctic Alaska. The types of streams ranged from spring to glacial. We anticipated that their macroinvertebrate communities would be dominated by a few habitat generalists resulting in only subtle differences in community structure among stream types due to the harsh Arctic environment. Seventy-two macroinvertebrate taxa were identified. Detrended Correspondence Analysis (DCA) indicated that these were distributed among five communities: tundra, tundra-spring, mountain, mountain-spring, and glacier. The distribution of community types along the major DCA axes were used to predict factors controlling their structure. These predictions were assessed using independent indicators of specific habitat attributes. Springs separated from mountain, glacier and tundra streams on the basis of a nutrient-freezing gradient. Springs have relatively high SRP concentrations and perennial flows, whereas mountain, glacier and tundra streams have low SRP concentrations and freeze solid during winter. Springs and tundra streams separated from mountain and glacier streams along an apparent bed-stability gradient. Spring streams and tundra streams have high bed-stability, whereas mountain streams and glacier streams have low bed-stability. This habitat template supports a level of freshwater biodiversity that was unanticipated and has implications for current understanding of the ecological function of streams draining Arctic landscapes.
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