Mean global surface temperature has risen 0.89°C over the past century and may increase by an additional 3-5°C by 2100. How freshwater ecosystems will respond is an important question, yet information allowing accurate predictions at the ecosystem-scale is lacking. We experimentally increased the temperature of a stream in Iceland by approximately 3.5°C using a geothermal heat exchanger system, and compared its invertebrate community with that of a reference stream for 1-year prior to warming and 2-years during warming. Experimental warming was associated with significant shifts in the relative abundance of several taxa. In particular, the abundance and biomass of the freshwater snails Radix peregra and Galba truncatula increased markedly with warming, while the abundance and biomass of several other taxa declined. Our results demonstrate directional shifts in species dominance that likely relate to whether taxa existed above or below their thermal optimum prior to experimental warming. Such taxon-specific responses to warming pose significant challenges for predicting community structure, species interactions, and food web dynamics in a warmer future.


Nelson, D., University of Alabama, USA, dnelson12@crimson.ua.edu

Benstead, J. P., University of Alabama, USA

Cross, W. F., Montana State University, USA

Huryn, A. D., University of Alabama, USA

Hood, J. M., Montana State University, USA

Johnson, P. W., University of Alabama, USA

Junker, J. R., Montana State University, USA

Gíslason, G. M., University of Iceland, Iceland

Ólafsson, J. S., Iceland Institute of Freshwater Fisheries, Iceland


Oral presentation

Session #:016
Date: 5/20/2014
Time: 17:00
Location: B 117 - 119

Presentation is given by student: Yes