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Societal Impact StatementThe invasive speciesS. alternifloraandP. australisare fast growing coastal wetland plants sequestering large amounts of carbon in the soil and protect coastlines against erosion and storm surges. In this global analysis, we found thatSpartinaandPhragmitesincrease methane but not nitrous oxide emissions, withPhragmiteshaving a lesser effect. The impact of the invasive species on emissions differed greatly among different types of native plant groups, providing valuable information to managers and policymakers during coastal wetland planning and restoration efforts. Further, our estimated net emissions per wetland plant group facilitate regional and national blue carbon estimates. SummaryGlobally,Spartina alternifloraandPhragmites australisare among the most pervasive invasive plants in coastal wetland ecosystems. Both species sequester large amounts of atmospheric carbon dioxide (CO2) and biogenic carbon in soils but also support production and emission of methane (CH4). In this study, we investigated the magnitude of their net greenhouse gas (GHG) release from invaded and non‐invaded habitats.We conducted a meta‐analysis of GHG fluxes associated with these two species and related soil carbon content and plant biomass in invaded coastal wetlands.Our results show that both invasive species increase CH4fluxes compared to uninvaded coastal wetlands, but they do not significantly affect CO2and N2O fluxes. The magnitude of emissions fromSpartinaandPhragmitesdiffers among native habitats. GHG fluxes, soil carbon and plant biomass ofSpartina‐invaded habitats were highest compared to uninvaded mudflats and succulent forb‐dominated wetlands, while being lower compared to uninvaded mangroves (except for CH4).This meta‐analysis highlights the important role of individual plant traits as drivers of change by invasive species on plant‐mediated carbon cycles.
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Biotic homogenization of wetland nematode communities by exotic Spartina alterniflora in China
Abstract Introduced species may homogenize biotic communities. Whether this homogenization can erase latitudinal patterns of species diversity and composition has not been well studied. We examined this by comparing nematode and microbial communities in stands of nativePhragmites australisand exoticSpartina alterniflorain coastal wetlands across 18° of latitude in China. We found clear latitudinal clines in nematode diversity and functional composition, and in microbial composition, for soils collected from nativeP. australis. These latitudinal patterns were weak or absent for soils collected from nearby stands of the exoticS. alterniflora. Climatic and edaphic variables varied across latitude in similar ways in both community types. InP. australisthere were strong correlations between community structure and environmental variables, whereas inS. alterniflorathese correlations were weak. These results suggest that the invasion ofS. alterniflorainto the Chinese coastal wetlands has caused profound biotic homogenization of soil communities across latitude. We speculate that the variation inP. australisnematode and microbial communities across latitude is primarily driven by geographic variation in plant traits, but that such variation in plant traits is largely lacking for the recently introduced exoticS. alterniflora. These results indicate that widespread exotic species can homogenize nematode communities at large spatial scales.
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- Award ID(s):
- 1832178
- PAR ID:
- 10448842
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Ecology
- Volume:
- 100
- Issue:
- 4
- ISSN:
- 0012-9658
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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