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TitlePathways for ecological change in Canadian High Arctic wetlands under rapid twentieth century warming
AuthorSim, T G; Swindles, G T; Morris, P J; Galka, M; Mullan, D; Galloway, J MORCID logo
SourceGeophysical Research Letters vol. 46, issue 9, 2019 p. 4726-4737, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20180298
PublisherAmerican Geophysical Union (AGU)
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html
ProvinceNorthwest Territories; Nunavut
NTS67B; 67C; 67D; 77; 78; 87; 88; 89A; 89B; 89C; 89D; 97G; 97H; 98; 99
AreaCambridge Bay; Canadian Arctic Archipelago; Victoria Island; Banks Island; Melville Island; Prince Patrick Island
Lat/Long WENS-128.0000 -100.0000 77.5000 68.0000
Subjectsenvironmental geology; surficial geology/geomorphology; soils science; geochronology; paleontology; Nature and Environment; ecology; paleoecology; climatology; wetlands; fens; permafrost; ground ice; periglacial features; ice wedges; climate, arctic; climate effects; temperature; soils; soil types; vegetation; microorganisms; carbon; ecosystems; meteorology; precipitation; lake sediment cores; pollen analyses; bulk density; radiometric dating; radiocarbon dating; carbon-14 dates; hydrologic environment; fossils; fossil plants; macrofossils; coastal environment; biological communities; Climate change; Birds; carbon sinks; lacustrine sediments
Illustrationsgeoscientific sketch maps; time series; photographs; profiles
ProgramEnvironmental Geoscience Metal Mining: northern baselines
Released2019 04 11
AbstractWe use paleoecological techniques to investigate how Canadian High Arctic wetlands responded to a mid-twentieth century increase in growing degree days. We observe an increase in wetness, moss diversity, and carbon accumulation in a polygon mire trough, likely related to ice wedge thaw. Contrastingly, the raised center of the polygon mire showed no clear response. Wet and dry indicator testate amoebae increased concomitantly in a valley fen, possibly relating to greater inundation from snowmelt followed by increasing evapotranspiration. This occurred alongside the appearance of generalist hummock mosses. A coastal fen underwent a shift from sedge to shrub dominance. The valley and coastal fens transitioned from minerogenic to organic-rich wetlands prior to the growing degree days increase. A subsequent shift to moss dominance in the coastal fen may relate to intensive grazing from Arctic geese. Our findings highlight the complex response of Arctic wetlands to warming and have implications for understanding their future carbon sink potential.
Summary(Plain Language Summary, not published)
The response of Arctic wetlands - and their large organic carbon store -to climate change is uncertain. We investigate the response of wetlands ecosystems in the Canadian High Arctic to twentieth century climate warming. We use proxies for changes in vegetation (plant macrofossils) and wetness (testate amoebae) preserved in the wetland soil in combination with radiocarbon dating to reconstruct the past ecology of these wetlands. This approach allows us to explore beyond the timeframe of monitoring studies. Our results show that wetland type is an important determinant of the response of ecological, hydrological and soil carbon accumulation to climate warming. These findings have important implications for understanding the future response of Arctic wetlands to warming and their potential for carbon sequestration.

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