Wetland invasion by Typha×glauca increases soil methane emissions

Abstract

34Wetland invasion by monotypic dominant plants can alter the physicochemical and biological 35 properties of soils that affect methane emissions, a potent greenhouse gas. We examined the 36 effects of Typha × glauca invasion on soil methane using laboratory incubation and controlled 37 mesocosm experiments. Typha-invaded soils collected from three Midwestern (USA) wetlands 38 had greater methane production potential during laboratory incubation than soils dominated by 39 native wet meadow vegetation. Ten years post-invasion of native plant-dominated mesocosms, 40Typha increased methane emissions at least three-fold (native: 15.0 ± 10.5 mg CH 4 -C m -2 h -1 , 41 median: 6.1 mg CH 4 -C m -2 h -1 ; Typha: mean: 45.9 ± 16.7 mg CH 4 -C m -2 h -1 , median: 26.8 mg 42 CH 4 -C m -2 h -1 ) under high (+10 cm) water levels, though methane emissions were negligible 43 under low (-10 cm) water levels. Methane emissions were positively correlated with soil carbon, 44 nitrogen, and aboveground biomass, all of which were greater in Typha-invaded mesocosms. 45Together, our data suggest that replacement of large tracts of native wetlands throughout eastern 46 North America with monocultures of invasive Typha could alter regional methane emissions. 47 48

Effects of experimental harvesting of an invasive hybrid cattail on wetland structure and function

“…We hypothesized that Typha removal would affect these parameters because previous studies demonstrated that these parameters can be altered by Typha invasion. Specifically, Typha invasion has been linked to higher soil carbon and inorganic nutrients (Angeloni et al ; Jankowski ; Lishawa et al ; Mitchell et al ), increased denitrification rates (Jankowski ; Lishawa et al ), and methane production (Lawrence et al ), and shifts in taxonomic composition of bacterial communities (Angeloni et al ). Therefore, we hypothesized that Typha removal might reverse some of these trends.…”

“…For example, Typha ‐dominated wetland sites have altered rates of both denitrification (Lishawa et al ) and nitrification (Vale ), as well as shifts in taxonomic composition of bacterial communities (Angeloni et al ) relative to more diverse wetland sites. An increase in methane production has also been documented in sediments from Typha invaded portions of wetlands (Lawrence et al ). Methane is a potent greenhouse gas, so increases in methane production have significant environmental implications.…”

“…Invasive plants threaten ecosystems by spreading rapidly and outcompeting native plant species (Richardson et al ), which can reduce plant biodiversity and wildlife habitat (Detenbeck et al ; Houlahan & Findlay ). Invasive plants can alter other ecosystem properties, including soil nutrient concentrations and composition and activity of belowground microbial communities (Kourtev et al ; Duda et al ; Ehrenfeld ; Zedler & Kercher ; Liao et al ), which can impact biogeochemical processes associated with native plant communities (Lishawa et al ; Lawrence et al ).…”

“…Methane is a potent greenhouse gas, so increases in methane production have significant environmental implications. Moreover, Lawrence et al () found that increased rates of methane production in Typha zones were not positively correlated with soil organic matter, possibly indicating changes in microbial community composition driven by invasive Typha .…”

Design Concept of an Automated Irrigation System for Simulating Saltwater Intrusion in a Mesocosm Experiment

“…Further, Carexstricta and Spartinapectinata are fresh-water grown plants; Typhalatifolia and Phragmitesaustralis are species commonly found in fresh to brackish wetlands Clump-forming species; Carexstricta, has higher levels of CH 4 emissions than other growth forms such as clonal dominant grasses [5]. Invasive species like Typhalatifolia produce large amounts of aboveground biomass; Typhalatifolia is associated with increased CH 4 production relative to less productive native communities [6]. Invasive strains of Phragmitesaustralis are a problematic and productive invader of coastal wetlands throughout eastern North America; Phragmitesaustralis is characterized by a high rate of biomass production as well as higher CH 4 emissions as compared to native Phragmites strains and native wetland species [7].…”