Ground conditions and surficial geology of the Kenai-Kasilof area, Kenai Peninsula, south-central Alaska

Klein et al. (2005, Can. J. For. Res. 35: 1931–1941) compare aerial photographs and report dramatically lower lake levels on the northern Kenai Peninsula, Alaska. They hypothesize that the lower lake levels may be caused by a decline in moisture surplus driven by climate change. However, the reported decline in surplus appears to be insufficient to explain the lower lake levels. Here I develop a simple sensitivity analysis to test their hypothesis and also show how tectonic processes such as the Great Alaskan earthquake could dramatically lower lake levels by fracturing an underlying aquitard. Tectonic processes, therefore, could potentially alter forest succession and wetland ecosystems by inducing hydrologic changes that mimic changes in climate.

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Time-dependent uplift of the Kenai Peninsula and adjacent regions of south central Alaska since the 1964 Prince William Sound earthquake

Journal of Geophysical Research Atmospheres ◽

10.1029/96jb00175 ◽

1996 ◽

Vol 101 (B4) ◽

pp. 8595-8604 ◽

Cited By ~ 20

Author(s):

Steven C. Cohen

Keyword(s):

Time Dependent ◽

Prince William Sound ◽

Kenai Peninsula ◽

South Central

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Comprhensive Approach to the Analysis of the 3D Kinematics Deformation with appliction to the Kenai Peninsula

Journal of Geodetic Science ◽

10.2478/v10156-010-0008-1 ◽

2011 ◽

Vol 1 (1) ◽

pp. 59-73 ◽

Cited By ~ 4

Author(s):

M. Hossainali ◽

M. Becker ◽

E. Groten

Keyword(s):

Surface Deformation ◽

Regularization Parameter ◽

Vertical Direction ◽

Three Dimensions ◽

Deformation Tensor ◽

Deformation Analysis ◽

Kenai Peninsula ◽

3D Kinematics ◽

South Central ◽

Lagrangian Formulations

Comprhensive Approach to the Analysis of the 3D Kinematics Deformation with appliction to the Kenai PeninsulaThe problem of analyzing surface deformation of the Earth's crust in three-dimensions is discussed. The isoparametric and Lagrangian formulations of deformation are extended from 2D to 3D. Analytical and numerical investigation of problem conditioning proves that analyzing the 3D kinematics of deformation can be an ill-posed problem. The required mathematical elements for solving this problem, including sensitivity analysis of the deformation tensor and regularization, are proposed. Regularized deformation tensors were computed using the method of truncated singular value decomposition (TSVD). The optimal regularization parameter was attained by minimizing regularization errors. Regularization errors were assessed using the corresponding 2D results of deformation analysis. The proposed methods were applied to the GPS network in the Kenai Peninsula, south-central Alaska, in order to compute the 3D pattern of postseismic crustal deformation in this area. Computed deformation in the vertical direction is compared to the existing pattern of vertical deformation obtained from the combination of precise leveling, gravity and GPS measurements from other studies on this area.

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

Canadian Journal of Forest Research ◽

10.1139/x05-129 ◽

2005 ◽

Vol 35 (8) ◽

pp. 1931-1941 ◽

Cited By ~ 106

Author(s):

Eric Klein ◽

Edward E Berg ◽

Roman Dial

Keyword(s):

Forest Cover ◽

Regional Analysis ◽

Water Bodies ◽

Woody Vegetation ◽

Field Sampling ◽

Regional Change ◽

Kenai Peninsula ◽

Aerial Photos ◽

South Central ◽

Spatial Area

This study documents the scale and intensity of drying over the last half century in the Kenai Lowlands of south-central Alaska. Using historical aerial photos and field sampling of wetlands, including muskegs, kettle ponds, and closed and open basin lakes, we present data on drying and successional changes in woody vegetation between 1950 and 1996. The results of this study suggest that the Kenai Peninsula is becoming both woodier in its vegetation and drier. A regional analysis of 1113 random points indicated increased forest cover and decreased open and wet areas in both burned and unburned areas between 1950 and 1996. A census of water bodies in three subregions indicates that almost two-thirds of water bodies visited show some level of decrease in spatial area. Over 80% of field sites visited have experienced some level of drying, where vegetation transects indicate substantial invasion into former lake beds by facultative upland plants. These results are consistent with a regional change in climate that is both warming and drying as documented in Kenai and Anchorage weather records.

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Presence of rapidly degrading permafrost plateaus in south-central Alaska

The Cryosphere ◽

10.5194/tc-10-2673-2016 ◽

2016 ◽

Vol 10 (6) ◽

pp. 2673-2692 ◽

Cited By ~ 15

Author(s):

Benjamin M. Jones ◽

Carson A. Baughman ◽

Vladimir E. Romanovsky ◽

Andrew D. Parsekian ◽

Esther L. Babcock ◽

...

Keyword(s):

Field Measurements ◽

Late Winter ◽

Organic Layer ◽

Frozen Ground ◽

Kenai Peninsula ◽

South Central ◽

Permafrost Table ◽

Long Time ◽

Protective Forest ◽

Reduction In Area

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 (1981–2010). 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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Mortality of white spruce during a spruce beetle outbreak on the Kenai Peninsula in Alaska

Canadian Journal of Forest Research ◽

10.1139/x83-014 ◽

1983 ◽

Vol 13 (1) ◽

pp. 96-101 ◽

Cited By ~ 15

Author(s):

Richard A. Werner ◽

Edward H. Holsten

Keyword(s):

White Spruce ◽

Permanent Plots ◽

Kenai Peninsula ◽

South Central ◽

Creek Watershed ◽

Spruce Beetle ◽

Spruce Stands ◽

Long Term Impact ◽

The Impact

White spruce (Piceaglauca (Moench) Voss) stands in the Resurrection Creek watershed in south-central Alaska were infested by spruce bettles, Dendroctonusrufipennis Kirby, between 1974 and 1975. Thirty permanent plots were established within the infested area in 1976 to evaluate the immediate and long-term impact on white spruce stands. Plots were revisited annually for 5 years. Between 1976 and 1980, 29% of all white spruce was killed by spruce beetles. This loss accounted for 59% of the commercial white spruce volume in the watershed. Mortality was greatest in the larger diameter classes during the early part of the infestation, but smaller diameter trees were subsequently attacked as the number of noninfested trees declined. The impact of spruce beetles on structure and species composition of white spruce stands is given along with a discussion of management implications.

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Genetic characterization of Kenai brown bears (Ursus arctos): microsatellite and mitochondrial DNA control region variation in brown bears of the Kenai Peninsula, south central Alaska

Canadian Journal of Zoology ◽

10.1139/z08-043 ◽

2008 ◽

Vol 86 (7) ◽

pp. 756-764 ◽

Cited By ~ 12

Author(s):

J. V. Jackson ◽

S. L. Talbot ◽

S. Farley

Keyword(s):

Mitochondrial Dna ◽

Genetic Variation ◽

Control Region ◽

Ursus Arctos ◽

Brown Bear ◽

Two Phase ◽

Brown Bears ◽

Kenai Peninsula ◽

South Central ◽

Haplotypic Diversity

We collected data from 20 biparentally inherited microsatellite loci, and nucleotide sequence from the maternally inherited mitochondrial DNA (mtDNA) control region, to determine levels of genetic variation of the brown bears ( Ursus arctos L., 1758) of the Kenai Peninsula, south central Alaska. Nuclear genetic variation was similar to that observed in other Alaskan peninsular populations. We detected no significant inbreeding and found no evidence of population substructuring on the Kenai Peninsula. We observed a genetic signature of a bottleneck under the infinite alleles model (IAM), but not under the stepwise mutation model (SMM) or the two-phase model (TPM) of microsatellite mutation. Kenai brown bears have lower levels of mtDNA haplotypic diversity relative to most other brown bear populations in Alaska.

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Recent woody invasion of wetlands on the Kenai Peninsula Lowlands, south-central Alaska: a major regime shift after 18 000 years of wet Sphagnum–sedge peat recruitment

Canadian Journal of Forest Research ◽

10.1139/x09-121 ◽

2009 ◽

Vol 39 (11) ◽

pp. 2033-2046 ◽

Cited By ~ 50

Author(s):

Edward E. Berg ◽

Kacy McDonnell Hillman ◽

Roman Dial ◽

Allana DeRuwe

Keyword(s):

Little Ice Age ◽

Regime Shift ◽

Black Spruce ◽

Ice Age ◽

Woody Vegetation ◽

Kenai Peninsula ◽

South Central ◽

Historical Aerial Photography ◽

Dwarf Birch ◽

Summer Temperatures

We document accelerating invasion of woody vegetation into wetlands on the western Kenai Peninsula lowlands. Historical aerial photography for 11 wetland sites showed that herbaceous area shrank 6.2%/decade from 1951 to 1968, and 11.1%/decade from 1968 to 1996. Corresponding rates for converting herbaceous area to shrubland were 11.5% and 13.7%/decade, respectively, and, for converting nonforest to forest, were 7.8% and 8.3%/decade, respectively. Black spruce ( Picea mariana (Mill.) BSP) forests on three wetland perimeters established since the Little Ice Age concluded in the 1850s. Dwarf birch shrubs at three wetland sites showed median apparent tree-ring age of 13 years, indicating recent shrub colonization at these sites. Peat cores at 24 wetland sites (basal peat ages 1840 – 18 740 calibrated years before present) indicated that these peatlands originated as wet Sphagnum –sedge fens with very little woody vegetation. Local meteorological records show a 55% decline in available water since 1968, of which one-third is due to higher summer temperatures and increased evapotranspiration and two-thirds is due to lower annual precipitation. These results suggest that wet Sphagnum–sedge fens initiating since the end of the Wisconsin glaciation began to dry in the 1850s and that this drying has greatly accelerated since the 1970s.

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