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

2005 ◽  
Vol 35 (8) ◽  
pp. 1931-1941 ◽  
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.

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

2009 ◽  
Vol 39 (11) ◽  
pp. 2033-2046 ◽  
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.

scholarly journals Biomass and mortmass of woody vegetation in metal-contaminated areas (Southern Urals, Russia)

2021 ◽  
Vol 9 ◽  
Author(s):  
Igor Bergman ◽  
Alexey Nesterkov
Keyword(s):  
Industrial Pollution ◽  
Forest Cover ◽  
Southern Urals ◽  
Copper Smelter ◽  
Forest Stand ◽  
Household Waste ◽  
Woody Vegetation ◽  
Global Changes ◽  
The Southern Urals ◽  
Dead Tree

Since the mid-2000s, long-term monitoring of various components of natural ecosystems under conditions of industrial pollution has been carried out in the Southern Urals. As a part of these monitoring programmes, the data on various components of biota in different biotopes, collected with different methods and in different time intervals, continue to be gathered. In addition, data collected through these monitoring programmes can also be used to study the local biodiversity of non-polluted areas. In 2012, in the vicinity of the Karabash Copper Smelter, a study of communities of small mammals was carried out, considering the heterogeneity of their habitats. Within the framework of this project, we presented a detailed description of the state of woody vegetation in the study area. The dataset (available from the GBIF network at https://www.gbif.org/dataset/61384edd-2d0a-437b-8cf0-ff4d2dfcc0da) includes the results of an assessment of the woody vegetation biomass at seven habitats (pine, birch and floodplain forests, reed swamp, sparse birch stand, marshy meadow and dump of household waste) of areas with different levels of industrial pollution in the vicinities of the Karabash, the Southern Urals. Karabash Copper Smelter (KCS) is one of Russia’s most significant point polluters; the main components of its emissions are heavy metals, dust and sulphur dioxide. Parameters of woody vegetation (diameter at breast height, diameter at root collar level and biomass) were estimated for seven forest elements (forest stand, subcanopy (undergrowth and underwood), half-dead tree of a forest stand and four types of coarse woody debris (downed bole, fragment of downed bole, standing dead tree and stump)) at 41 sampling plots (20 at unpolluted and 21 at polluted areas) and 165 subplots (81 and 84, respectively). The dataset includes 411 sampling events (estimation events of the forest elements at sampling plots and subplots), corresponding to 5786 occurrences (estimations of the woody vegetation components) observed during July 2012. For most woody vegetation components (72%), an estimate of the above-ground phytomass is given. For each sampling event, information on the presence or absence of woody vegetation species at the considered habitats is provided (a total of 1479 occurrences with status "absent"). The dataset can be used for environmental monitoring, sustainable forest management, modelling forest productivity considering global changes, studying the structure and biodiversity of forest cover and assessing forests’ carbon-sequestration capacity. In addition, the dataset provides information about different forest ecosystems under the influence of strong industrial pollution.

scholarly journals Thirty-Year Spatiotemporal Change Record of Sundarban Mangrove Forest in Bangladesh

2021 ◽  
Vol 24 (2) ◽  
pp. 15-32
Author(s):  
KMM Uzzaman ◽  
MG Miah ◽  
HM Abdullah ◽  
MR Islam ◽  
MSI Afrad ◽  
...  
Keyword(s):  
Mangrove Forest ◽  
Forest Cover ◽  
Water Bodies ◽  
Forest Monitoring ◽  
Continuous Change ◽  
Forest Cover Change ◽  
Subsequent Increase ◽  
Stable Pattern ◽  
Sundarban Mangrove ◽  
Conservation And Management

Accurate and realistic forest cover change assessment is essential for the conservation and management of the Sundarban mangrove forest of Bangladesh. With these views, an integrated way of the vegetation cover assessment was conducted using time-series Landsat satellite imageries of 1991, 2001, 2011, and 2021. During the last 30-year (1991-2021), variations in four land cover classes viz. healthy vegetation, unhealthy vegetation, water body, and sandbar were recorded. It showed a decreasing trend of forest vegetation and a subsequent increase of water bodies during the study period. The healthy vegetation and unhealthy vegetation decreased at 1.33 and 1.66%, respectively, whereas water bodies increased 2.55% at the same time. The healthy vegetation consistently decreased over the decades, but unhealthy vegetation decreased during the 2001-2011 period. Conversion from healthy vegetation to unhealthy vegetation and unhealthy vegetation to healthy vegetation during 1991-2001 was similar. Such transform was much higher from unhealthy to healthy vegetation during 2001-2011. Transformation of healthy vegetation to unhealthy vegetation was remarkably higher during the 2011-2021 period. Further continuous change detection and classification algorithm (CCDC) showed a stable pattern over the study period without significant breakpoints. This study reveals the need for regular mangrove forest monitoring. The findings of this study can be used as a reference in the formulation and implementation of sustainable mangrove forest conservation and management. Ann. Bangladesh Agric. (2020) 24(2): 15-32

scholarly journals Assessing Harvested Sites in a Forested Boreal Mountain Catchment through Global Forest Watch

2019 ◽  
Vol 11 (5) ◽  
pp. 543 ◽  
Author(s):  
Fernando Rossi ◽  
Johannes Breidenbach ◽  
Stefano Puliti ◽  
Rasmus Astrup ◽  
Bruce Talbot
Keyword(s):  
Forest Cover ◽  
Risk Mitigation ◽  
Landsat Imagery ◽  
Aerial Images ◽  
Catchment Management ◽  
South Central ◽  
Cable Yarding ◽  
The Mean ◽  
Steep Terrain ◽  
Forest Cover Loss

Global Forest Watch (GFW) provides a global map of annual forest cover loss (FCL) produced from Landsat imagery, offering a potentially powerful tool for monitoring changes in forest cover. In managed forests, FCL primarily provides information on commercial harvesting. A semi-autonomous method for providing data on the location and attributes of harvested sites at a landscape level was developed which could significantly improve the basis for catchment management, including risk mitigation. FCL in combination with aerial images was used for detecting and characterising harvested sites in a 1607 km2 mountainous boreal forest catchment in south-central Norway. Firstly, the forest cover loss map was enhanced (FCLE) by removing small isolated forest cover loss patches that had a high probability of representing commission errors. The FCLE map was then used to locate and assess sites representing annual harvesting activity over a 17-year period. Despite an overall accuracy of >98%, a kappa of 0.66 suggested only a moderate quality for detecting harvested sites. While errors of commission were negligible, errors of omission were more considerable and at least partially attributed to the presence of residual seed trees on the site after harvesting. The systematic analysis of harvested sites against aerial images showed a detection rate of 94%, but the area of the individual harvested site was underestimated by 29% on average. None of the site attributes tested, including slope, area, altitude, or site shape index, had any effect on the accuracy of the area estimate. The annual harvest estimate was 0.6% (standard error 12%) of the productive forest area. On average, 96% of the harvest was carried out on flat to moderately steep terrain (<40% slope), 3% on steep terrain (40% to 60% slope), and 1% on very steep terrain (>60% slope). The mean area of FCLE within each slope category was 1.7 ha, 0.9 ha, and 0.5 ha, respectively. The mean FCLE area increased from 1.0 ha to 3.2 ha on flat to moderate terrain over the studied period, while the frequency of harvesting increased from 249 to 495 sites per year. On the steep terrain, 35% of the harvesting was done with cable yarding, and 62% with harvester-forwarder systems. On the very steep terrain (>60% slope), 88% of the area was harvested using cable yarding technology while harvesters and forwarders were used on 12% of the area. Overall, FCL proved to be a useful dataset for the purpose of assessing harvesting activity under the given conditions.

Comment on “Wetland drying and succession across the Kenai Peninsula Lowlands, south-central Alaska”Appears in Can. J. For. Res. 35: 1931-1941 (2005).

2011 ◽  
Vol 41 (2) ◽  
pp. 425-428 ◽  
Author(s):  
Michael B. Gracz
Keyword(s):  
Climate Change ◽  
Sensitivity Analysis ◽  
Forest Succession ◽  
Aerial Photographs ◽  
Lake Levels ◽  
Kenai Peninsula ◽  
Wetland Ecosystems ◽  
South Central ◽  
Tectonic Processes

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.

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

2011 ◽  
Vol 1 (1) ◽  
pp. 59-73 ◽  
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.

Studies of birds in a semi-arid area of Kenya. III The use of ‘Timed Species-counts’ for studying regional avifaunas

1986 ◽  
Vol 2 (3) ◽  
pp. 231-247 ◽  
Author(s):  
Derek Pomeroy ◽  
Beatrice Tengecho
Keyword(s):  
Essential Feature ◽  
Fixed Time ◽  
Woody Vegetation ◽  
Resident Species ◽  
Simple Method ◽  
South Central ◽  
Terrestrial Habitats ◽  
Total Species ◽  
Made In ◽  
Central Kenya

ABSTRACT‘Times Species-counts’ are a simple method of comparing the avifaunas of extensive areas by sampling representative habitats. The method has been evaluated in south central Kenya but could be applied to most terrestrial regions of tropical Africa. The essential feature is that the observers move anywhere within a sample site of about 1 km2, recording all of the species seen in a fixed time, e.g. 1 h.Counts are made in all seasons and at various times of day. Reasonable estimates of the total number of species in an area can be derived from a series of 15 counts, but such estimates tend to be low in non-forested habitats because ‘wanderers’ (non-resident species) continue to be recorded almost indefinitely. Open sites have far fewer species than well-wooded areas. The numbers of resident species in non-forested terrestrial habitats is related both to the amount of woody vegetation and to a measure of plant growth. However, total species numbers seem to depend solely on the amount of woody vegetation. Road counts, from a vehicle, were compared to those made on foot. They are less satisfactory, especially for cryptic species.

scholarly journals Regional analysis of the change factors in the oak (Quercus sp.) forest cover in the Tehuacán-Cuicatlán region, Mexico

2020 ◽  
Vol 26 (2) ◽  
pp. 189-205
Author(s):  
Laura Paulina Osorio-Olvera ◽  
◽  
Arturo García-Romero ◽  
Stéphane André Couturier ◽  
Francisco Guerra-Martínez ◽  
...  
Keyword(s):  
Forest Cover ◽  
Regional Analysis ◽  
Change Factors
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