Comparisons of Macrophyte Breakdown, Associated Plant Chemistry, and Macroinvertebrates in a Wastewater Dominated Stream

• Published in: International review of hydrobiology. Vol. 96; no. 1; pp. 72 - 89
• Main Author: Nelson, S. Mark
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.02.2011; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Applied sciences; Biological and medical sciences; decomposition; erosion control structure; Exact sciences and technology; exotic invasive; Fundamental and applied biological sciences. Psychology; General aspects; Pollution; Smicridea; Synecology; urban; Wastewaters; Water treatment and pollution; Decomposition; Urban area; exotic invasive; erosion control structure; Invasion; Waste water; Smicridea; Aquatic environment; Chemistry; Hydrobiology; urban; Stream; Aquatic plant; Invertebrata; Erosion
• ISSN: 1434-2944; 1522-2632; 1522-2632
• DOI: 10.1002/iroh.201011314

Replacement of native macrophyte species with exotic or invasive ones affects the quality of detritus entering streams and can alter nutrient cycles and community structure in aquatic ecosystems. Decomposition of air‐dried native hardstem bulrush (Schoenoplectus acutus), invasive southern cattail (Typha domingensis), and exotic common reed (Phragmites australis) were studied in an urban stream (Las Vegas, Nevada, USA) using litter bags. Samples were analyzed for dry mass, lignin, nutrients, trace elements, and macroinvertebrates. Litter type and sediment deposited on plant material influenced material loss. Trace elements arsenic and selenium increased in plant material to concentrations considered marginal for ecosystem contamination by exposure day 76. Mercury increases were inconsistent across plant species and did not exceed limits. Bulrush decomposed faster, and tended to have higher selenium concentrations, than did invasive southern cattail and exotic common reed. Macroinvertebrate communities colonizing litter bags were similar across plant litter types, but differed from mesh‐only bags and samples collected with a kick‐net. Macroinvertebrate exclusion resulted in significantly lower loss rates, but functional feeding groups such as shredders were not associated with decomposition differences. The caddisfly, Smicridea, physically modified stem material and aided in processing, but microbes appeared most important in biological material breakdown. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)