Sensitivity of Erosion‐Rate in Permafrost Landscapes to Changing Climatic and Environmental Conditions Based on Lake Sediments From Northwestern Alaska

Abstract

Erosion of landscapes underlaid by permafrost can transform sediment and nutrient fluxes, surface and subsurface hydrology, soil properties, and rates of permafrost thaw, thus changing ecosystems and carbon emissions in high latitude regions with potential implications for global climate. However, future rates of erosion and sediment transport are difficult to predict as they depend on complex interactions between climatic and environmental parameters such as temperature, precipitation, permafrost, vegetation, wildfires, and hydrology. Thus, despite the potential influence of erosion on the future of the Arctic and global systems, the relations between erosion‐rate and these parameters, as well as their relative importance, remain largely unquantified. Here we quantify these relations based on a sedimentary record from Burial Lake, Alaska, one of the richest datasets of Arctic lake deposits. We apply a set of bi‐ and multi‐variate techniques to explore the association between the flux of terrigenous sediments into the lake (a proxy for erosion‐rate) and a variety of biogeochemical sedimentary proxies for paleoclimatic and environmental conditions over the past 25 cal ka BP. Our results show that erosion‐rate is most strongly associated with temperature and vegetation proxies, and that erosion‐rate decreases with increased temperature, pollen‐counts, and abundance of pollen from shrubs and trees. Other proxies, such as those associated with fire frequency, aeolian dust supply, mass wasting and hydrologic conditions, play a secondary role. The marginal effects of the sedimentary‐proxies on erosion‐rate are often threshold dependent, highlighting the potential for strong non‐linear changes in erosion in response to future changes in Arctic conditions.

Hillslope and vegetation response to postglacial warming at Bear Meadows Bog, Pennsylvania, USA

“…For example, woody shrub proliferation at the expense of mosses and sedges is thought to be an indicator of modern Arctic disturbance (Berner et al, 2020; Myers-Smith et al, 2020). However, current studies struggle to disentangle whether shrub expansion fuels erosion on permafrost hillslopes or vice versa (Tape et al, 2011; Shelef et al, 2022), and whether shrub expansion would result in a net increase or decrease in either soil temperatures or carbon stored in soil (Myers-Smith et al, 2011). Nitrogen fixation allows Alnus to readily colonize recently disturbed areas with low levels of N availability such as fire and erosion scars (Myers-Smith et al, 2011).…”

“…At Bear Meadows, we report the stratigraphy of the Bear Meadows (S-02) core without the coarse inorganic basal unit because the transition is undated. permafrost hillslopes or vice versa (Tape et al, 2011;Shelef et al, 2022), and whether shrub expansion would result in a net increase or decrease in either soil temperatures or carbon stored in soil (Myers-Smith et al, 2011). Nitrogen fixation allows Alnus to readily colonize recently disturbed areas with low levels of N availability such as fire and erosion scars (Myers-Smith et al, 2011).…”

Suspended sediment deposition and sediment yields at Lake Peters, northeast Brooks Range, Alaska: Fluvial‐ and lake‐based approaches

“…Similar climate change‐driven increases in erosion and sediment yield are reported for other cold regions worldwide, including in High Mountain Asia (Li et al, 2021), the European Alps (Lane et al, 2019) and the Andes (Vergara et al, 2022). In low‐relief, non‐glacial terrain of northwestern Alaska, a recently published lake sediment flux record has shown counterintuitive and complex flux relations with temperature and other environmental proxies over 25 000 years (Shelef et al, 2022). For our single lake catchment study, with only a 2‐year interval representing recent fluxes, longer term study of upstream sediment dynamics is needed to link trends, such as the elevated delivery we associated with a 2016 rainfall event, to specific sediment sources and process regimes, as well as to place recent yields into the context of regional environmental change.…”

“…We considered reasons for disparities in Arctic SSYs, especially catchment area (Lewis & Lamoureux, 2010;Milliman & Syvitski, 1992;Syvitski, 2002) and glacier cover (Church & Ryder, 1972;Guymon, 1974;Hallet et al, 1996;Hasholt, 2016;Lewkowicz & Wolfe, 1994). In the conventional area-scaling model of SSY, increased propensity for lowland sediment storage within larger catchments results in lower SSYs, comparative to smaller catchments with less potential for sediment trapping (Chorley et al, 1984;Milliman & Meade, 1983;Schiefer et al, 2001;Schumm, 1977). In our regional comparison of non-glacierized catchments, there is a flat or weakly increasing trend of SSY with catchment area.…”

Flood vulnerability assessment trough overlay-scoring data method based on Geographical Information System (GIS) in Giriwoyo, Wonogiri, Indonesia

“…Non-paddy agricultural land is able to provide optimal infiltration capabilities [30]. The rest is a scrub area that is able to withstand the rate of soil erosion [31]. The vulnerable category covers 5780.19 ha or 54.16% of all study areas spread across each village.…”