Characterization of Schoenoplectus pungens in a Great Lakes Coastal Wetland and a Pacific Northwestern Estuary

摘要

This study seeks to identify key components of structure and growth habit of Schoenoplectus pungens (bulrush) that allow it to thrive in severe environments. Schoenoplectus pungens, an emergent herbaceous plant growing in shallow, high energy freshwater and brackish coastal wetlands, occurs throughout North America and several continents. We observe the plant in ecologically distinctive Laurentian Great Lakes and Pacific Northwestern estuaries. Plant populations were characterized in terms of above-ground and below-ground biomass, stem density, diameter, height, and flexibility. Plants grown in flooded planters for research were compared with populations in their natural environments. The modulus of elasticity was found to be similar for planter- and wild-grown plants from fresh and brackish waters. Aerenchyma tissue, important for conducting oxygen to roots, increased with flooding and possibly reduced stem flexibility. Stem diameter and height increased as water depths or flooding increased, while below-ground biomass decreased. Soils ranging from coarse gravels to clays supported S. pungens. Most regeneration occurs as sprouts from rhizomes, not seedlings. Below-ground biomass accounted for a greater proportion of total biomass than above-ground biomass in most zones. This study collected large below-ground biomass samples that allowed for more effective evaluation of root and rhizome structure than traditional small samples.