Late Pleistocene Vegetation of Kings Canyon, Sierra Nevada, California

1983 ◽  
Vol 19 (1) ◽  
pp. 117-129 ◽  
Author(s):  
Kenneth Cole
Keyword(s):  
Plant Community ◽  
Sierra Nevada ◽  
Late Pleistocene ◽  
Coniferous Forest ◽  
Pollen Grains ◽  
Mean Annual Precipitation ◽  
Juniperus Occidentalis ◽  
Sequoiadendron Giganteum ◽  
Western Side ◽  
Modern Sample

AbstractSeven packrat midden samples make possible a comparison between the modern and late Pleistocene vegetation in Kings Canyon on the western side of the southern Sierra Nevada. One modern sample contains macrofossils and pollen derived from the present-day oak-chaparral vegetation. Macrofossils from the six late Pleistocene samples record a mixed coniferous forest dominated by the xerophytic conifers Juniperus occidentalis, Pinus cf. ponderosa, and P. monophylla. The pollen spectra of these Pleistocene middens are dominated by Pinus sp., Taxodiaceae-Cupressaceae-Taxaceae (TCT), and Artemisia sp. Mesophytic conifers are represented by low macrofossil concentrations. Sequoiadendron giganteum is represented by a few pollen grains in the full glacial. Edaphic control and snow dispersal are the most likely causes of these mixed assemblages.The dominant macrofossils record a more xeric plant community than those that now occur on similar substrates at higher elevations or latitudes in the Sierra Nevada. These assemblages suggest that late Wisconsin climates were cold with mean annual precipitation not necessarily greater than modern values. This conclusion supports a model of low summer ablation allowing for the persistence of the glaciers at higher elevations during the late Wisconsin. The records in these middens also suggest that S. giganteum grew at lower elevations along the western side of the range and that P. monophylla was more widely distributed in cismontane California during the Pleistocene.

Timing of the last Deglaciation in the Sierra Nevada of the Mérida Andes, Venezuela

2013 ◽  
Vol 80 (3) ◽  
pp. 482-494 ◽  
Author(s):  
Julien Carcaillet ◽  
Isandra Angel ◽  
Eduardo Carrillo ◽  
Franck A. Audemard ◽  
Christian Beck
Keyword(s):  
Sierra Nevada ◽  
Late Pleistocene ◽  
Younger Dryas ◽  
Ice Cover ◽  
Published Data ◽  
Last Deglaciation ◽  
The Last Deglaciation ◽  
Absolute Age ◽  
Glacial Landforms

In the tropical Mérida Andes (northwestern Venezuela), glacial landforms were found at altitudes between 2600 and 5000 m, corresponding to 600 km2 of ice cover during the maximum glacial extension. However, the lack of sufficient absolute age data prevents detailed reconstruction of the timing of the last deglaciation. On the northwestern flank of the Mucuñuque Massif, successive moraines and striated eroded basement surfaces were sampled for cosmogenic 10Be investigation. Their compilation with published data allows the establishment of a detailed chronology of the post-LGM glacier history. The oldest moraines (18.1 and 16.8 ka) correspond to the Oldest Dryas. Successive moraine ridges indicate stops in the overall retreat between the LGM and the Younger Dryas. The cold and short Older Dryas stadial has been identified. Results indicate that most of the ice withdrew during the Pleistocene. The dataset supports an intensification of the vertical retreat rate from ~ 25 m/ka during the late Pleistocene to ~ 310 m/ka during the Pleistocene/Holocene. Afterwards, the glacier was confined and located in the higher altitude zones. The altitude difference of the Younger Dryas moraines in the Mucubají, La Victoria and Los Zerpa valleys indicates a strong effect of valley orientation on the altitude of moraine development.

scholarly journals Habitat Selection in a Changing Environment: The Relationship Between Habitat Alteration and Spotted Owl Territory Occupancy and Breeding Dispersal

The Condor ◽  
2007 ◽  
Vol 109 (3) ◽  
pp. 566-576 ◽  
Author(s):  
Mark E. Seamans ◽  
R.J. Gutiérrez
Keyword(s):  
Habitat Selection ◽  
Sierra Nevada ◽  
Coniferous Forest ◽  
Canopy Cover ◽  
Habitat Alteration ◽  
Breeding Dispersal ◽  
Conifer Forest ◽  
Avian Behavior ◽  
Spotted Owl ◽  
The Relationship

Abstract Abstract. Understanding the effect of habitat alteration on avian behavior is important for understanding a species' ecology and ensuring its conservation. Therefore, we examined the relationship between Spotted Owl habitat selection and variation in habitat in the Sierra Nevada. We estimated habitat selection by modeling the probability of territory colonization (γ), territory extinction (ε), and breeding dispersal in relation to the amount of mature conifer forest within and among territories. Alteration of ≥20 ha of mature conifer forest (coniferous forest with >70% canopy cover dominated by medium [30.4–60.9 cm dbh] and large [>60.9 cm dbh] trees) within individual territories (n  =  66) was negatively related to territory colonization and positively related to breeding dispersal probability. Although territory extinction was negatively related to the amount of mature conifer forest, it was not clear whether this relationship was due to variation of mature conifer forest within or among territories. Although modeling results for territory colonization and extinction generally supported the hypothesis that individuals are “ideal” when selecting a habitat in the sense that they settle in the highest-quality site available, we did not find a clear benefit in terms of habitat quality for Spotted Owls that exhibited breeding dispersal.

Late Pleistocene age, size, and paleoenvironment of a caribou antler from Haida Gwaii, British Columbia

2019 ◽  
Vol 56 (6) ◽  
pp. 688-692 ◽  
Author(s):  
Rolf W. Mathewes ◽  
Michael Richards ◽  
Thomas E. Reimchen
Keyword(s):  
British Columbia ◽  
Late Pleistocene ◽  
Vegetation Cover ◽  
Coniferous Forest ◽  
Bone Collagen ◽  
Haida Gwaii ◽  
Terrestrial Vertebrates ◽  
Mis 3 ◽  
Basal Portion ◽  
Marine Isotope Stage 3

The basal portion of a fossil caribou antler from Graham Island is the only evidence of large terrestrial vertebrates older than the Fraser (late-Wisconsin) glaciation on Haida Gwaii. This antler has been radiocarbon dated three times by different laboratories and all ages fall within the mid-Wisconsin Olympia Interglaciation (Marine Isotope Stage 3, MIS 3). We suggest that the latest date, using ultrafiltration of bone collagen, is closest to the true age at 43 200 ± 650 years BP (48 200 – 45 200 cal BP). Previous paleoecological analysis from Graham Island reconstructed a vegetation cover during MIS 3 consisting of mixed coniferous forest with nonforested openings, similar to cool subalpine forests of today. These conditions are consistent with environments that support woodland caribou and the related extinct Dawson caribou. Morphometric comparison of antlers from woodland and Dawson caribou suggest that they are more similar than previously interpreted and raise questions about the inferred differences between the mainland and island subspecies.

scholarly journals Botryosphaeria Dothidea and Neofusicoccum Yunnanense Causing Canker and Die-Back of Sequoiadendron Giganteum in Croatia

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 695
Author(s):  
Marta Kovač ◽  
Danko Diminić ◽  
Saša Orlović ◽  
Milica Zlatković
Keyword(s):  
Sierra Nevada ◽  
Phylogenetic Analyses ◽  
Management Strategies ◽  
Housekeeping Genes ◽  
First Record ◽  
Pathogenicity Test ◽  
Botryosphaeria Dothidea ◽  
Ornamental Tree ◽  
Sequoiadendron Giganteum ◽  
The Impact

Sequoiadendron giganteum Lindl. [Buchholz] is a long-lived tree species endemic to the Sierra Nevada Mountains in California. Due to its massive size and beauty, S. giganteum is a popular ornamental tree planted in many parts of the world, including Europe. Since 2017, scattered branch die-back has been observed on S. giganteum trees in Zagreb, Croatia. Other symptoms included resinous branch cankers, reddish-brown discoloration of the sapwood and, in severe cases, crown die-back. Branches showing symptoms of die-back and cankers were collected from six S. giganteum trees in Zagreb and the aim of this study was to identify the causal agent of the disease. The constantly isolated fungi were identified using morphology and phylogenetic analyses based on the internal transcribed spacer (ITS) of the ribosomal DNA (rDNA), and partial sequencing of two housekeeping genes, i.e., translation elongation factor 1-α (TEF 1-α), and β tubulin 2 (TUB2). The fungi were identified as Botryosphaeria dothidea (Moug.) Ces. and De Not. and Neofusicoccum yunnanense G.Q. Li & S.F. Chen. The pathogenicity test was conducted in a plant growth chamber on S. giganteum seedlings and revealed that N. yunnanense was more aggressive compared to B. dothidea. N. yunnanense was able to reproduce symptoms of canker and die-back and kill plants seven weeks after inoculation whereas B. dothidea produced cankers. To the best of our knowledge, this is the first report of B. dothidea and N. yunnanense causing canker and die-back disease of S. giganteum in Croatia. It is also the first record on the identity and pathogenicity of any fungal species associated with S. giganteum in this country. The study expended the known host range of N. yunnanense to include S. giganteum, which is a valuable ornamental tree in Croatian landscapes. Disease management strategies should be developed to mitigate or reduce the impact of the disease.

Late Pleistocene and Late Holocene Lake Highstands in the Pyramid Lake Subbasin of Lake Lahontan, Nevada, USA

2005 ◽  
Vol 64 (2) ◽  
pp. 257-263 ◽  
Author(s):  
Richard W. Briggs ◽  
Steven G. Wesnousky ◽  
Kenneth D. Adams
Keyword(s):  
Sierra Nevada ◽  
Late Pleistocene ◽  
Late Holocene ◽  
Large Lakes ◽  
Western Basin ◽  
Radiocarbon Dates ◽  
Beach Ridges ◽  
Climate Proxy ◽  
Pyramid Lake ◽  
Proxy Records

AbstractShoreline geomorphology, shoreline stratigraphy, and radiocarbon dates of organic material incorporated in constructional beach ridges record large lakes during the late Pleistocene and late Holocene in the Pyramid Lake subbasin of Lake Lahontan, Nevada, USA. During the late Holocene, a transgression began at or after 3595 ± 35 14C yr B.P. and continued, perhaps in pulses, through 2635 ± 40 14C yr B.P., resulting in a lake as high as 1199 m. During the latest Pleistocene and overlapping with the earliest part of the Younger Dryas interval, a lake stood at approximately 1212 m at 10,820 ± 35 14C yr B.P. and a geomorphically and stratigraphically distinct suite of constructional shorelines associated with this lake can be traced to 1230 m. These two lake highstands correspond to periods of elevated regional wetness in the western Basin and Range that are not clearly represented in existing northern Sierra Nevada climate proxy records.

Reconstruction of a semi-arid late Pleistocene paleocatena from the Lake Victoria region, Kenya

2015 ◽  
Vol 84 (3) ◽  
pp. 368-381 ◽  
Author(s):  
Emily J. Beverly ◽  
Steven G. Driese ◽  
Daniel J. Peppe ◽  
L. Nicole Arellano ◽  
Nick Blegen ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Homo Sapiens ◽  
Lake Victoria ◽  
Mean Annual Precipitation ◽  
Equatorial Africa ◽  
Lake Victoria Region ◽  
Rainfall Reduction ◽  
Few Data ◽  
Volcaniclastic Deposits ◽  
The Last Glacial

The effect of changing environment on the evolution of Homo sapiens is heavily debated, but few data are available from equatorial Africa prior to the last glacial maximum. The Karungu deposits on the northeast coast of Lake Victoria are ideal for paleoenvironmental reconstructions and are best studied at the Kisaaka site near Karunga in Kenya (94 to > 33 ka) where paleosols, fluvial deposits, tufa, and volcaniclastic deposits (tuffs) are exposed over a ~ 2 km transect. Three well-exposed and laterally continuous paleosols with intercalated tuffs allow for reconstruction of a succession of paleocatenas. The oldest paleosol is a smectitic paleo-Vertisol with saline and sodic properties. Higher in the section, the paleosols are tuffaceous paleo-Inceptisols with Alfisol-like soil characteristics (illuviated clay). Mean annual precipitation (MAP) proxies indicate little change through time, with an average of 764 ± 108 mm yr− 1 for Vertisols (CALMAG) and 813 ± 182 to 963 ± 182 mm yr− 1 for all paleosols (CIA-K). Field observations and MAP proxies suggest that Karungu was significantly drier than today, consistent with the associated faunal assemblage, and likely resulted in a significantly smaller Lake Victoria during the late Pleistocene. Rainfall reduction and associated grassland expansion may have facilitated human and faunal dispersals across equatorial East Africa.

scholarly journals Estimating the atmospheric boundary layer height over sloped, forested terrain from surface spectral analysis during BEARPEX

2010 ◽  
Vol 10 (11) ◽  
pp. 25759-25801 ◽  
Author(s):  
W. Choi ◽  
I. C. Faloona ◽  
M. McKay ◽  
A. H. Goldstein ◽  
B. Baker
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Sierra Nevada ◽  
Sonic Anemometer ◽  
Coniferous Forest ◽  
Power Spectra ◽  
Nocturnal Boundary Layer ◽  
Layer Height ◽  
Boundary Layer Height ◽  
Stable Conditions

Abstract. In this study the atmospheric boundary layer (ABL) height (zi) over complex, forested terrain is estimated based on the power spectra and the integral length scale of horizontal winds obtained from a three-axis sonic anemometer during the BEARPEX (Biosphere Effects on Aerosol and Photochemistry) Experiment. The zi values estimated with this technique showed very good agreement with observations obtained from balloon tether sonde (2007) and rawinsonde (2009) measurements under unstable conditions (z/L < 0) at the coniferous forest in the California Sierra Nevada. The behavior of the nocturnal boundary layer height (h) and power spectra of lateral winds and temperature under stable conditions (z/L > 0) is also presented. The nocturnal boundary layer height is found to be fairly well predicted by a recent interpolation formula proposed by Zilitinkevich et al. (2007), although it was observed to only vary from 60–80 m during the experiment. Finally, significant directional wind shear was observed during both day and night with winds backing from the prevailing west-southwesterlies in the ABL (anabatic cross-valley circulation) to consistent southerlies in a layer ~1 km thick just above the ABL before veering to the prevailing westerlies further aloft. We show that this is consistent with the forcing of a thermal wind driven by the regional temperature gradient directed due east in the lower troposphere.

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