Forested wetlands may represent important ecosystems for mitigating climate change effects through carbon (C) sequestration because of their slow decomposition and C storage by trees. Despite this potential importance, few studies have acknowledged the role of temperate treed swamps in the C cycle. In southwest Nova Scotia, Canada, we examined the role of treed swamps in the soil C cycle by determining C inputs through litterfall, assessing decomposition rates and soil C pools, and quantifying C outputs through soil greenhouse gas (GHG) emissions. The treed swamps were found to represent large supplies of C inputs through litterfall to the forest floor. The swamp soils had substantially greater C stores than the swamp-upland edge or upland soils. We found growing season C inputs via litterfall to exceed C outputs via GHG emissions in the swamps by a factor of about 2.5. Our findings indicate that temperate treed swamps can remain a C sink even if soil GHG emissions were to double, supporting conservation efforts to preserve temperate treed swamps as a measure to mitigate climate change.

Key Messages• Glaciers in the northern Mackenzie Mountains were mapped using Landsat satellite images.• A statistically significant decreasing trend in glacier area from 1987 to 2017 was found to exist (52.8 ± 2.6% overall, or 1.8% · a −1 ). • Continuation of this trend will result in the study area being free of visible glacier cover within three decades.The state of a group of glaciers in the northern Mackenzie Mountains across the Yukon-Northwest Territories border was investigated over a period of three decades, using Landsat TM and OLI imagery from to examine changes in glacier extents. A thresholded red/ shortwave infrared band ratio image was used to delineate glacier boundaries. The total area of 74 glaciers in the study area decreased from 52.78 ± 1.32 km 2 in 1987 to 24.89 ± 0.62 km 2 in 2017, a loss of 27.89 ± 1.39 km 2 or 52.8 ± 2.6%, with a mean rate of reduction of 1.8% · a −1 . Smaller glaciers experienced larger relative changes in area. In this study, the rates of reduction are high compared to decreases reported for other glaciers in the region in the late 20 th century. Based on linear extrapolation of the trend in values of total glacier area, it is predicted-subject to uncertainties in how glaciers diminish in size and eventually disappear-that the study area could be free of visible glacier cover within three decades.