title: Impacts of multiple stressors on ecosystem function: Leaf decomposition in constructed urban wetlands.
abstract: The impact of stormwater on stream biota is well documented, but less is known about the impacts on ecosystem processes, such as the breakdown of organic matter. This study sought to establish whether the degree of urbanisation affected rates of leaf-litter breakdown within constructed wetlands. A litter bag method was used to ascertain rate of decomposition along a gradient of urbanisation (total imperviousness, TI), in constructed wetlands in western and south-eastern Melbourne. A significant positive relationship between TI and breakdown rate was found in the south-eastern wetlands. The significant reduction in rate of invertebrate-mediated breakdown with increasing concentration of certain metals was consistent with other studies. However, overall there was an increase in rate of breakdown. Studies have shown that the effects of heavy metals can be negated if nutrient levels are high. Our results suggest that other parameters besides exposure to contaminants are likely to affect leaf litter breakdown.
authors.affiliation: School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia. Electronic address: teresa.mackintosh@monash.edu.
authors.forename: Teresa J
authors.initials: TJ
authors.lastname: Mackintosh
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia. Electronic address: Jenny.Davis@canberra.edu.au.
authors.forename: Jenny A
authors.initials: JA
authors.lastname: Davis
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia. Electronic address: Ross.Thompson@canberra.edu.au.
authors.forename: Ross M
authors.initials: RM
authors.lastname: Thompson
mesh_terms: D000818:Animals; D001315:Australia; D017753:Ecosystem; D052918:Environmental Restoration and Remediation; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology; D007448:Invertebrates / Q000187:drug effects; D019216:Metals, Heavy / Q000032:analysis / Q000633:toxicity*; D064307:Microbiota / Q000187:drug effects; D018515:Plant Leaves / Q000737:chemistry*; D014507:Urbanization; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*; D053833:Wetlands
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical
keywords: Constructed wetlands; Decomposition; Leaf bags; Metals; Stormwater; Total imperviousness