Inventorying climate-induced landscape changes and associated impacts on lakes and rivers in Old Crow Flats, Yukon, Canada
Abstract
Changing climate conditions have induced widespread responses across northern lake-rich permafrost landscapes including shrub vegetation proliferation, retrogressive thaw slumps (RTSs), and fire. We are inventorying these changes and investigating the associated impacts on lake and river biogeochemistry and geomorphology in Old Crow Flats (OCF), Yukon, Canada. OCF is the traditional territory of the Vuntut Gwitchin First Nation who is concerned about the influence that changing climate and landscape characteristics will have on their traditional lifestyles. Vegetation greening was detected using time-series analysis of Landsat during 1985-2013. Greening has mostly occurred in peripheral areas of OCF along the northern and southern mountain-lowland ecotone. We are evaluating spatial association of these vegetation changes and monitored lake and river hydroecological conditions. Zelma Lake, which has been monitored since draining in 2007, is providing a valuable model showing lake biogeochemical responses to shrub encroachment. The influence of RTSs on downstream conditions is being evaluated along the OCF drainage network. Repeat remotely piloted aerial surveys were conducted over the largest slump since 2016, when it initially exported ~29,174 m3 sediment. It exported 47,509 m3 by August 2018. Downstream DIC and DOC were influenced most during the initial wet thaw season. More sediment was exported during the relatively hot and dry summer 2017 than during the cooler and wetter summer 2018. Ongoing analysis is investigating the utility of LVIS and UAVSAR data for detecting permafrost slump characteristics along the Old Crow River. Fire occurring during 2017 influenced a lake monitored since 2007. Post-burn results show the lake received less snowmelt input and experienced increases in phosphorus and ion concentrations. AVIRIS-NG data is being used to classify catchment pre and post-burn land cover properties. Results being generated here will help anticipate how lakes and rivers will respond in permafrost environments if the frequency and magnitude of climate-induced landscape changes increase.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B13D..05T
- Keywords:
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- 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCES;
- 0475 Permafrost;
- cryosphere;
- and high-latitude processes;
- BIOGEOSCIENCES