Wetland drying and succession across the Kenai Peninsula Lowlands, south-central Alaska

Klein, E. S.; Berg, Edward E.; Dial, Roman

doi:10.1139/x05-129

Cited by 141 publications

(123 citation statements)

References 18 publications

(27 reference statements)

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“…Berg and Anderson (2006) caution that overall drier conditions on the western Kenai Peninsula, combined with standing dead spruce stands, may alter the future fire regime of this region. Wetland drying (Klein et al, 2005) and establishment of woody vegetation in wetlands (Berg et al, 2009) may be attributed to warmer air temperatures and decreases in precipitation. Furthermore, tectonic activity associated with the Great Alaska Earthquake of 1964 caused the western Kenai Peninsula to lower in elevation by 0.7-2.3 m (Plafker, 1969), while the northern portion of the peninsula subsequently uplifted 0.8-0.9 m (Cohen and Freymueller, 1997), potentially altering groundwater flow paths (Gracz, 2011).…”

Section: Landscape Dynamics and Permafrost Thaw In The Western Kenai mentioning

confidence: 99%

Presence of rapidly degrading permafrost plateaus in south-central Alaska

et al. 2016

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Abstract. Permafrost presence is determined by a complex interaction of climatic, topographic, and ecological conditions operating over long time scales. In particular, vegetation and organic layer characteristics may act to protect permafrost in regions with a mean annual air temperature (MAAT) above 0 • C. In this study, we document the presence of residual permafrost plateaus in the western Kenai Peninsula lowlands of south-central Alaska, a region with a MAAT of 1.5 ± 1 • C . Continuous ground temperature measurements between 16 September 2012 and 15 September 2015, using calibrated thermistor strings, documented the presence of warm permafrost (−0.04 to −0.08 • C). Field measurements (probing) on several plateau features during the fall of 2015 showed that the depth to the permafrost table averaged 1.48 m but at some locations was as shallow as 0.53 m. Late winter surveys (augering, coring, and GPR) in 2016 showed that the average seasonally frozen ground thickness was 0.45 m, overlying a talik above the permafrost table. Measured permafrost thickness ranged from 0.33 to > 6.90 m. Manual interpretation of historic aerial photography acquired in 1950 indicates that residual permafrost plateaus covered 920 ha as mapped across portions of four wetland complexes encompassing 4810 ha. However, between 1950 and ca. 2010, permafrost plateau extent decreased by 60.0 %, with lateral feature degradation accounting for 85.0 % of the reduction in area. Permafrost loss on the Kenai Peninsula is likely associated with a warming climate, wildfires that remove the protective forest and organic layer cover, groundwater flow at depth, and lateral heat transfer from wetland surface waters in the summer. Better understanding the resilience and vulnerability of ecosystem-protected permafrost is critical for mapping and predicting future permafrost extent and degradation across all permafrost regions that are currently warming. Further work should focus on reconstructing permafrost history in south-central Alaska as well as additional contemporary observations of these ecosystem-protected permafrost sites south of the regions with relatively stable permafrost.

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Section: Landscape Dynamics and Permafrost Thaw In The Western Kenai mentioning

confidence: 99%

Presence of rapidly degrading permafrost plateaus in south-central Alaska

et al. 2016

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“…As different types of wetlands sequester and emit at different rates [8], it is important to discriminate between wetland types in mapping efforts. This is particularly important for monitoring changes in wetland type, with previous studies noting increases in shrub abundance [12], a reduction in size or loss of water bodies [13,14] and drying of wetland areas [15] within Alaska.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of ALOS PALSAR Data for High-Resolution Mapping of Vegetated Wetlands in Alaska

et al. 2015

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As the largest natural source of methane, wetlands play an important role in the carbon cycle. High-resolution maps of wetland type and extent are required to quantify wetland responses to climate change. Mapping northern wetlands is particularly important because of a disproportionate increase in temperatures at higher latitudes. Synthetic aperture radar data from a spaceborne platform can be used to map wetland types and dynamics over large areas. Following from earlier work by using Japanese Earth Resources Satellite (JERS-1) data, we applied the "random forests" classification algorithm to variables from L-band ALOS PALSAR data for 2007, topographic data (e.g., slope, elevation) and locational information (latitude, longitude) to derive a map of vegetated wetlands in Alaska, with a spatial resolution of 50 m. We used the National Wetlands Inventory and National Land Cover Database (for upland areas) to select training and validation data and further validated classification results with an independent dataset that we created. A number of improvements were made to the method of Whitcomb et al. (2009): (1) more consistent training data in upland areas; (2) better distribution of training data across Remote Sens. 2015, 7 7273 all classes by taking a stratified random sample of all available training pixels; and (3) a more efficient implementation, which allowed classification of the entire state as a single entity (rather than in separate tiles), which eliminated discontinuities at tile boundaries. The overall accuracy for discriminating wetland from upland was 95%, and the accuracy at the level of wetland classes was 85%. The total area of wetlands mapped was 0.59 million km 2 , or 36% of the total land area of the state of Alaska. The map will be made available to download from NASA's wetland monitoring website.

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“…Some lakes have shown inward-flow and salinization phenomena with a decreasing water surface, and others shown expansion. It has been concluded that the major mechanism for drying water bodies in no-permafrost zone was decreased water balance in a warming climate (Klein et al 2005). The shrunk and split of Gyaring Hu, Ngoring Hu, Xinxinhai, Xinsuhai, Duogcuorengiang, Mitijiangmuco, Rumchanco and Wupuemoco Lake in the Tibetan Plateau could be applied to validate the mechanism (Guo et al 2003;Bian et al 2006;Shao et al 2007;Li et al 2008;Wu et al 2008;Niu et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Changing inland lakes responding to climate warming in Northeastern Tibetan Plateau

et al. 2011

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The main portion of Tibetan Plateau has experienced statistically significant warming over the past 50 years, especially in cold seasons. This paper aims to identify and characterize the dynamics of inland lakes that located in the hinterland of Tibetan Plateau responding to climate change. We compared satellite imageries in late 1970s and early 1990s with recent to inventory and track changes in lakes after three decades of rising temperatures in the region. It showed warm and dry trend in climate with significant accelerated increasing annual mean temperature over the last 30 years, however, decreasing periodically annual precipitation and no obvious trend in potential evapotranspiration during the same period. Our analysis indicated widespread declines in inland lake's abundance and area in the whole origin of the Yellow River and southeastern origin of the Yangtze River. In contrast, the western and northern origin of the Yangtze River revealed completely reverse change. The regional lake surface area decreased by 11,499 ha or 1.72% from the late 1970s to the early 1990s, and increased by 6,866 ha or 1.04% from the early 1990s to 2004. Shrinking inland lakes may become a common feature in the discontinuous permafrost regions as a consequence of warming climate and thawing permafrost. Furthermore, obvious expanding were found in continuous permafrost regions due to climate warming and glacier retreating. The results may provide information for the scientific recognition of the responding events to the climate change recorded by the inland lakes.

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Wetland drying and succession across the Kenai Peninsula Lowlands, south-central Alaska

Cited by 141 publications

References 18 publications

Presence of rapidly degrading permafrost plateaus in south-central Alaska

Presence of rapidly degrading permafrost plateaus in south-central Alaska

Evaluation of ALOS PALSAR Data for High-Resolution Mapping of Vegetated Wetlands in Alaska

Changing inland lakes responding to climate warming in Northeastern Tibetan Plateau

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