Estensen, J. L. University of Alaska Fairbanks, fsjle2@uaf.edu
Braddock, J. L. University of Alaska Fairbanks, ffjfb@uaf.edu
Oswood, M. W. University of Alaska Fairbanks, ffmwo@uaf.edu
Bryant, J. P. University of Alaska Fairbanks, fsjpb@uaf.edu
Irons III, J. G. University of Alaska Fairbanks, fnjgi@uaf.edu

 
WINTER VERTEBRATE BROWSING OF BIRCH: EFFECTS ON THE USE OF LEAF LEACHATES BY STREAM MICROBES
 
This study examined the effects of winter moose browsing on stream microbial use of dissolved organic carbon (DOC) leachates produced from birch, Betula resinifera, leaf litter. Winter herbivory can affect leaf chemistry, increasing nitrogen and decreasing secondary compound contents in leaves of the following growing season, potentially affecting the quality of DOC leachates produced from those leaves. The effects of moose browsing were tested by producing leachate from leaves collected from browsed and unbrowsed trees. Each leachate was then microbially inoculated with an aliquot of finely ground decaying leaf matter. Microbial respiration (oxygen uptake) and bacterial abundance (microscopic direct counts) were used to assess qualitative differences in the leachates. Microbes in browsed leachate had a higher rate of respiration than those in unbrowsed leachate, but there was no difference in bacterial abundance between the treatments. There were no detectable tannins in either leachate; however, the total amino acid concentration was 25% greater in the browsed leachate. The DOC leachate from browsed leaves was of higher quality than from unbrowsed leaves, likely attributable to a higher amino acid concentration.
 
Day: Thursday, Feb. 4
Time: 03:45 - 04:00pm
Location: Sweeney Center
 
Code: SS33TH0345S