Early Registration Deadline
12 February 2010

Travel Award & Grant Recipients Notified
March 2010

Authors Notified
April 2010

Schedule Posted
January 2010

Mineau, M. M., Idaho State University, Stream Ecology Center, Department of Biological Sciences, Pocatello, ID, USA, minemade@isu.edu
Baxter, C. V., Idaho State University, Stream Ecology Center, Department of Biological Sciences, Pocatello, ID, USA, baxtcold@isu.edu
Marcarelli, A. M., Michigan Technological University, Department of Biological Sciences, Houghton, MI, USA, ammarcar@mtu.edu
Minshall, G. W., Idaho State University, Stream Ecology Center, Department of Biological Sciences, Pocatello, ID, USA, minswayn@isu.edu

RETENTIVE OR LEAKY: HOW DO STREAM ECOSYSTEMS RESPOND TO CARBON AND NITROGEN SUBSIDIES FROM NON-NATIVE RUSSIAN OLIVE (ELAEAGNUS ANGUSTIFOLIA)?

Russian olive (RO) is an invasive riparian tree widespread throughout the western USA. RO fixes nitrogen and consequently provides subsidies of nitrogen-rich litter and groundwater to streams. RO also contributes a subsidy of carbon via litter fall. We evaluated nutrient limitation of biofilms and measured nitrate and ammonium uptake in upstream-reference and downstream-invaded reaches of 6 streams in Idaho and Wyoming. Magnitude of chlorophyll-a increase on nitrogen addition treatments was lower in invaded compared to reference reaches. Nitrate and ammonium uptake velocities were significantly faster in invaded compared to reference reaches (paired t-test P= 0.05 and 0.03 respectively). In one stream, we constructed carbon budgets for an invaded and a reference reach and compared these to pre-invasion data. At the invaded reach, we observed a 30-fold increase in leaf-litter inputs, but little change in community respiration. We found RO doubled in-stream carbon storage as benthic organic matter and increased particulate terrestrial carbon export from 0.15 to 7.91 g/day. These findings indicate that the nitrogen subsidy from RO is processed in streams biologically while carbon inputs are primarily stored and exported.

Session #:S10
Date: 06-11-10
Time: 15:30

Presentation is given by student: Yes