Roach, J. K., B. Griffith, and D. Verbyla. Landscape influences on climate-related lake shrinkage at high latitudes. Global Change Biology doi: 10.1111/gcb.12196
Abstract
Climate-related declines in lake area have been identified across circumpolar regions and have been characterized by
substantial spatial heterogeneity. An improved understanding of the mechanisms underlying lake area trends is
necessary to predict where change is most likely to occur and to identify implications for high latitude reservoirs of
carbon. Here, using a population of ca. 2300 lakes with statistically significant increasing and decreasing lake area
trends spanning longitudinal and latitudinal gradients of ca. 1000 km in Alaska, we present evidence for a mechanism
of lake area decline that involves the loss of surface water to groundwater systems. We show that lakes with
significant declines in lake area were more likely to be located: (1) in burned areas; (2) on coarser, well-drained soils;
and (3) farther from rivers compared to lakes that were increasing. These results indicate that postfire processes such
as permafrost degradation, which also results from a warming climate, may promote lake drainage, particularly in
coarse-textured soils and farther from rivers where overland flooding is less likely and downslope flow paths and
negative hydraulic gradients between surface water and groundwater systems are more common. Movement of
surface water to groundwater systems may lead to a deepening of subsurface flow paths and longer hydraulic
residence time which has been linked to increased soil respiration and CO2 release to the atmosphere. By quantifying
relationships between statewide coarse resolution maps of landscape characteristics and spatially heterogeneous
responses of lakes to environmental change, we provide a means to identify at-risk lakes and landscapes and plan for
a changing climate.