Holocene subalpine forest-parkland dynamics in Big Cottonwood Canyon, Wasatch Mountains, Utah, USA

The Holocene ◽  
2020 ◽  
pp. 095968362097276
Author(s):  
David Rhode ◽  
Lisbeth A Louderback ◽  
Sandy O Brugger
Keyword(s):  
Large Scale ◽  
Local Context ◽  
Future Climate Change ◽  
Subalpine Forest ◽  
Conifer Forest ◽  
Holocene Climate ◽  
Local Factors ◽  
Wasatch Mountains ◽  
Silver Lake

Understanding long-term responses of subalpine forest-parklands to Holocene climate variability in local context is critical for better managing those ecosystems under future climate change. Available records suggest that western North American subalpine forest-parkland ecosystems responded to Holocene climate in various ways at different places. Here we present a Holocene record of upper montane forest-parkland dynamics from Silver Lake in Big Cottonwood Canyon, Wasatch Range, on the Great Basin’s eastern margin. Our results show that at the end of the Younger Dryas, Silver Lake was surrounded by open Pinus/Picea parkland mixed with Artemisia subalpine steppe. By ~9.0 cal ka BP Picea began to expand in response to early Holocene summer warming and enhanced winter moisture. Picea-dominated forests prevailed from ~8.0 to 5.0 cal ka BP, after which time a more open Picea parkland developed. By ~3.5 cal ka BP Pinus increased under cooling conditions, and Picea gradually rebounded to form the mixed conifer forest present today. The Silver Lake long-term record of moderate shifts within an upper montane ecosystem is consistent with other regional sites in the timing of major vegetation changes reflecting large-scale climatic forcings, but distinct in response to local factors including the importance of enhanced lake-effect snowpack and the absence of competing lower montane Pinus. These local factors may help account for the long-term stability of Picea-dominated forests in the area.

scholarly journals Structure of the Pacific Walker Circulation Depicted by the Reanalysis and CMIP6

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1219
Author(s):  
Emmanuel Olaoluwa Eresanya ◽  
Yuping Guan
Keyword(s):  
Large Scale ◽  
Structural Changes ◽  
Numerical Models ◽  
Walker Circulation ◽  
Future Climate Change ◽  
Western Boundary ◽  
Extreme Caution ◽  
The Pacific ◽  
Mean State

The Pacific Walker circulation (PWC) is one of the most important components of large-scale tropical atmospheric circulations. The PWC and its influences have been studied extensively by numerical models and reanalysis. The newly released ERA5 and NCEP2 are the most widely used reanalysis datasets and serve as benchmarks for evaluation of model simulations. If the results of these datasets differ significantly, this could lead to a bias in projected long-term climate knowledge. For better understanding of future climate change, it is necessary to evaluate PWC reanalysis productions. As a result, we compared the PWC structures between the ERA5 and NCEP2 datasets from month to seasonal time scales. We used the zonal mass streamfunction (ZMS) over the equatorial Pacific to indicate the strength of the PWC. The PWC’s average monthly or seasonal cycle peaks around July. From February to June, the NCEP2 shows a higher PWC intensity, whereas the ERA5 shows greater intensity from July to December. The circulation center in the NCEP2 is generally stronger and wider than in the ERA5. The ERA5, however, revealed that the PWC’s west edge (zero line of ZMS over the western Pacific) had moved 10 degrees westward in comparison to the NCEP2. In addition, we compared the PWC mean state in the reanalysis and CMIP6 models; the mean state vertical structures of the tropical PWC in the CMIP6 multi-model ensemble (MME) are similar to those of the reanalyses in structure but weaker and wider than in the two reanalysis datasets. The PWC is broader in CMIP6, and the western boundary is 7 and 17 degrees farther west than in the ERA5 and NCEP2, respectively. This study suggests that, when using reanalysis datasets to evaluate PWC structural changes in intensity and western edge, extreme caution should be exercised.

Introduction

2008 ◽  
Vol 18 (1) ◽  
pp. 57-59 ◽  
Author(s):  
John Robb
Keyword(s):  
Environmental Conditions ◽  
Social Stratification ◽  
Large Scale ◽  
Academic Life ◽  
Local Context ◽  
Archaeological Theory ◽  
Local Response ◽  
Short Term ◽  
Power Strategies

Time and change have been among the most widely discussed themes in archaeological theory, though they have varying fortunes in the vicissitudes of academic life. British and American anthropology, it has been observed, have long oscillated between history and evolution, between studying culture in its local context and in a long-term narrative. Following Steward and White rather than Kroeber and Boas, the New Archaeology's banner was evolution, and many of its theoretical goals were explicitly reductionist, for example, in viewing human actions as a local response to large-scale environmental conditions. Yet, at the same time, from its inception the New Archaeology also contained the seeds of a humanistic, historical approach (for instance, in tracing social stratification to chiefly power strategies to local, short-term political contexts).

scholarly journals Drivers of amphibian population dynamics and asynchrony at local and continental scales

2019 ◽  
Author(s):  
Hugo Cayuela ◽  
Richard A. Griffiths ◽  
Nurul Zakaria ◽  
Jan W. Arntzen ◽  
Pauline Priol ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Population Growth ◽  
Density Dependence ◽  
Large Scale ◽  
Structured Populations ◽  
Habitat Characteristics ◽  
List Type ◽  
Population Synchrony ◽  
Local Factors

ABSTRACTIdentifying the drivers of population fluctuations in spatially distinct populations remains a significant challenge for ecologists. Whereas regional climatic factors may generate population synchrony (i.e., Moran effect), local factors including the level of density-dependence may reduce the level of synchrony. Although divergences in the scaling of population synchrony and spatial environmental variation have been observed, the regulatory factors that underlie such mismatches are poorly understood.No previous studies have investigated how density-dependent processes and population-specific responses to weather variation influence spatial synchrony at both local and continental scales. We addressed this issue in a pond-breeding amphibian, the great crested newt (Triturus cristatus). We used capture-recapture data collected through long-term surveys in five T. cristatus populations in Western Europe.We found a low level of demographic synchrony at both local and continental levels. Weather has weak and spatially variable effects on survival, recruitment and population growth rate. In contrast, density-dependence was a common phenomenon (at least for population growth) in almost all populations and subpopulations.Our findings support the idea that Moran’s effect is low in species where the population dynamics more closely depends on local factors (e.g. population density and habitat characteristics) than on large-scale environmental fluctuation (e.g. regional climatic variation). Those demographic feature likely have far-reaching consequences for the long-term viability of the spatially structured populations and their ability to response to large-scale climatic anomalies.

Comparison of emperor penguin declines between Pointe Géologie and Haswell Island over the past 50 years

2011 ◽  
Vol 23 (5) ◽  
pp. 461-468 ◽  
Author(s):  
Christophe Barbraud ◽  
Maria Gavrilo ◽  
Yuri Mizin ◽  
Henri Weimerskirch
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Future Climate Change ◽  
Emperor Penguin ◽  
Sea Ice Extent ◽  
Island Populations ◽  
Dramatic Decline ◽  
Ice Conditions ◽  
Long Term Trends

AbstractThe emperor penguin (Aptenodytes forsteri) is highly dependent on sea ice conditions, and future climate change may affect its distribution and numbers. Most studies on the demography and population dynamics of emperor penguins in relation to sea ice characteristics were conducted at a single colony (Pointe Géologie). Several non-exclusive hypotheses have been proposed to explain the dramatic decline of this colony, including changes in sea ice conditions, predation, flipper banding and human disturbance. Here, we report and analyse updated long-term trends in numbers of breeding pairs made at two colonies (Pointe Géologie and Haswell Island) where counts are comparable. Similar changes were observed for both colonies and paralleled changes in sea ice extent. At Pointe Géologie and Haswell Island, populations declined similarly and later growth rates were also similar since the early 1990s for Haswell and early 1980s for Pointe Géologie. The magnitude of the decline was similar between both colonies when numbers of breeding pairs were assessed. This study suggests that a common large-scale environmental factor has probably negatively affected both colonies.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

Computer Analyses in Preventive Health Research

1967 ◽  
Vol 06 (01) ◽  
pp. 8-14 ◽  
Author(s):  
M. F. Collen
Keyword(s):  
Medical Research ◽  
Preventive Medicine ◽  
Health Research ◽  
Large Scale ◽  
Preventive Health ◽  
New Era ◽  
Large Numbers ◽  
Normal Test ◽  
Computer Analyses

The utilization of an automated multitest laboratory as a data acquisition center and of a computer for trie data processing and analysis permits large scale preventive medical research previously not feasible. Normal test values are easily generated for the particular population studied. Long-term epidemiological research on large numbers of persons becomes practical. It is our belief that the advent of automation and computers has introduced a new era of preventive medicine.

(A review) Atlas of especially protected natural areas of Saint Petersburg / Ed. in chief V. N. Khramtsov, T. V. Kovaleva, N. Yu. Natsvaladze. St. Petersburg, 2013. 176 p.

2014 ◽  
pp. 124-129
Author(s):  
Z. V. Karamysheva
Keyword(s):  
Protected Areas ◽  
Large Scale ◽  
Natural Areas ◽  
Natural Protected Areas ◽  
Saint Petersburg ◽  
Natural Processes ◽  
Original Illustrations ◽  
Vegetation Maps ◽  
Protected Natural Areas

The review contains detailed description of the «Atlas of especially protected natural areas of Saint Petersburg» published in 2013. This publication presents the results of long-term studies of 12 natural protected areas made by a large research team in the years from 2002 to 2013 (see References). The Atlas contains a large number of the historical maps, new satellite images, the original illustrations, detailed texts on the nature of protected areas, summary tables of rare species of vascular plants, fungi and vertebrates recorded in these areas. Special attention is paid to the principles of thematic large-scale mapping. The landscape maps, the vegetation maps as well as the maps of natural processes in landscapes are included. Reviewed Atlas deserves the highest praise.

Etude de l'aménagement d'une forêt classée au Mali avec la participation des populations riveraines - Données du problème et éléments de méthodologie | A Study of the Management of a State-Owned Forest in Mali with the Participation of the Population Living nearby - Issue under Investigation and Elements of Methodology

2000 ◽  
Vol 151 (3) ◽  
pp. 80-83
Author(s):  
Pascal Schneider ◽  
Jean-Pierre Sorg
Keyword(s):  
Natural Resources ◽  
Research Methodology ◽  
Large Scale ◽  
Environmental Context ◽  
Forest Resources ◽  
The State ◽  
Commercial Use ◽  
Economic Context ◽  
The People

In and around the state-owned forest of Farako in the region of Sikasso, Mali, a large-scale study focused on finding a compromise allowing the existential and legitimate needs of the population to be met and at the same time conserving the forest resources in the long term. The first step in research was to sketch out the rural socio-economic context and determine the needs for natural resources for autoconsumption and commercial use as well as the demand for non-material forest services. Simultaneously, the environmental context of the forest and the resources available were evaluated by means of inventories with regard to quality and quantity. According to an in-depth comparison between demand and potential, there is a differentiated view of the suitability of the forest to meet the needs of the people living nearby. Propositions for a multipurpose management of the forest were drawn up. This contribution deals with some basic elements of research methodology as well as with results of the study.

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