The ability of three-square bulrush (Schoenoplectus pungens) to expand at the same rate as the climate change driven decline in Great Lakes levels

Abstract

The declining lake levels in the Great Lakes fit with current climate change models. Costal marshes are especially susceptible to drying events with small changes in lake levels. The three‐square bulrushes (Schoenoplectus pungens) hold important roles of habitat, erosion control, and anthropogenic pollution control within coastal wetlands. The measurement of gradient change perpendicular to the shoreline estimated the ability of bulrush to respond to declining levels. Through sampling of two coastal marshes dominated by S. pungens, we determined the growth pattern in three inundation zones: 1. Dry‐ dry year round and has been dry for many years, 2. Shore‐ fluctuating level of water year round and has been dry in the previous years, and 3. Deep‐ continuously inundated year round and has been for many years. Through sampling, the relative importance of inundation levels and zone characteristics was determined to affect the relative growth with higher inundation perceived to lead to higher growth. The Deep zone had the greatest growth potential with the Shore and Dry zones showing a significant difference only at the terminal node. Zones showed differences in growth patterns between horizontal main rhizome growth and vertical short shoot growth. The rate of growth seems inadequate to respond to declining lake levels.