Microsatellite survey reveals possible link between triploidy and mortality of quaking aspen in Kaibab National Forest, Arizona

2015 ◽  
Vol 45 (10) ◽  
pp. 1369-1375 ◽  
Author(s):  
Groves B. Dixon ◽  
Laura E. DeWald
Keyword(s):  
United States ◽  
Environmental Factors ◽  
Microsatellite Markers ◽  
Populus Tremuloides ◽  
Ploidy Level ◽  
National Forest ◽  
Quaking Aspen ◽  
Predisposing Factor ◽  
Kaibab National Forest ◽  
Crown Dieback

In the southwestern United States, populations of quaking aspen (Populus tremuloides Michx.) are experiencing widespread mortality. Although environmental factors contributing to mortality have been well characterized, less is known about how genotype and particularly ploidy level affect susceptibility. We used five microsatellite markers to infer the ploidy level of 212 aspen stems in Kaibab National Forest, Arizona. Many multilocus genotypes showed three alleles at one or more loci, suggestive of frequent triploidy among our samples. Sites populated with putative triploids had higher mortality. In addition, heterozygosity was positively associated with mortality and crown dieback. Our results suggest that triploidy is a predisposing factor for aspen mortality in Kaibab National Forest.

Wildfire Occurrence in Aspen in the Interior Western United States

1987 ◽  
Vol 2 (3) ◽  
pp. 73-76 ◽  
Author(s):  
Norbert V. DeByle ◽  
Collin D. Bevins ◽  
William C. Fischer
Keyword(s):  
United States ◽  
Populus Tremuloides ◽  
Prescribed Fire ◽  
Western United States ◽  
National Forest ◽  
Quaking Aspen ◽  
Wildfire Occurrence ◽  
Management Intervention ◽  
Forest Lands

Abstract The western United States contains more than 7 million acres of quaking aspen (Populus tremuloides). On the majority of this acreage, aspen sprouted as even-aged stands after fires in the last 150 years. For several reasons, however, fire evidently is no longer playing its historic role of killing and regenerating western aspen stands. A survey was made of wildfire occurrence from 1970 through 1982 in aspen stands on National Forest lands in three Forest Service Regions. The survey data, expanded to include all aspen acreage, revealed that an average of 600 acres are annually consumed by fire. At this rate, it would require about 12,000 years to burn the entire aspen type in the West. During this time span, without management intervention, seral aspen will probably be replaced by conifers, and stable aspen stands may become all-aged and perhaps less productive. Use of prescribed fire is recommended. West. J. Appl. For. 2(3):73-76, July 1987.

scholarly journals Remote sensing of ploidy level in quaking aspen ( Populus tremuloides Michx.)

2019 ◽  
Vol 108 (1) ◽  
pp. 175-188 ◽  
Author(s):  
Benjamin Blonder ◽  
Bente J. Graae ◽  
Burke Greer ◽  
Marja Haagsma ◽  
Kenny Helsen ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Populus Tremuloides ◽  
Ploidy Level ◽  
Quaking Aspen

Influence of climate on the growth of quaking aspen (Populus tremuloides) in Colorado and southern Wyoming

2015 ◽  
Vol 45 (11) ◽  
pp. 1546-1563 ◽  
Author(s):  
M.M. Dudley ◽  
J. Negron ◽  
N.A. Tisserat ◽  
W.D. Shepperd ◽  
W.R. Jacobi
Keyword(s):  
Populus Tremuloides ◽  
Radial Growth ◽  
Summer Precipitation ◽  
White Rot ◽  
Annual Precipitation ◽  
Quaking Aspen ◽  
Canopy Closure ◽  
Stand Damage ◽  
Beetle Damage ◽  
Crown Dieback

We analyzed a series of increment cores collected from 260 adult dominant or co-dominant quaking aspen (Populus tremuloides Michx.) trees from national forests across Colorado and southern Wyoming in 2009 and 2010. Half of the cores were collected from trees in stands with a high amount of crown dieback, and half were from lightly damaged stands. We define the level of stand damage based on stand survey data in which lightly damaged stands had average crown dieback of 16% and heavily damaged stands averaged 41%. Upon analysis, two-thirds of the cores collected did not exhibit radial growth correlated with region-wide patterns (e.g., climate) and were classified as having a low cohesive response. The site variable most predictive of whether a stand exhibited high cohesive response or low cohesive response was site elevation, followed by aspect, slope, and canopy closure. Sites with high cohesive response stands were more likely to have aspen bark beetle damage, white rot, and Cryptosphaeria canker. We did not detect relationships between tree growth and summer precipitation from 1900–2008, but there was a relationship between growth and annual precipitation. A growth model included maximum May and July temperatures, as well as the current and previous year’s annual precipitation.

Mass School Shootings in the United States: A Novel Root Cause Analysis Using Lay Press Reports

2019 ◽  
Vol 58 (13) ◽  
pp. 1423-1428 ◽  
Author(s):  
Chris A. Rees ◽  
Lois K. Lee ◽  
Eric W. Fleegler ◽  
Rebekah Mannix
Keyword(s):  
United States ◽  
Environmental Factors ◽  
Root Cause Analysis ◽  
The United States ◽  
School Shootings ◽  
Contributing Factors ◽  
Mass Shootings ◽  
Cause Analysis ◽  
Factors Associated ◽  
Root Cause

School shootings comprise a small proportion of childhood deaths from firearms; however, these shootings receive a disproportionately large share of media attention. We conducted a root cause analysis of 2 recent school shootings in the United States using lay press reports. We reviewed 1760 and analyzed 282 articles from the 10 most trusted news sources. We identified 356 factors associated with the school shootings. Policy-level factors, including a paucity of adequate legislation controlling firearm purchase and ownership, were the most common contributing factors to school shootings. Mental illness was a commonly cited person-level factor, and access to firearms in the home and availability of large-capacity firearms were commonly cited environmental factors. Novel approaches, including root cause analyses using lay media, can identify factors contributing to mass shootings. The policy, person, and environmental factors associated with these school shootings should be addressed as part of a multipronged effort to prevent future mass shootings.

scholarly journals Polyploidy influences plant–environment interactions in quaking aspen (Populus tremuloides Michx.)

2017 ◽  
Vol 38 (4) ◽  
pp. 630-640 ◽  
Author(s):  
Burke T Greer ◽  
Christopher Still ◽  
Grace L Cullinan ◽  
J Renée Brooks ◽  
Frederick C Meinzer
Keyword(s):  
Populus Tremuloides ◽  
Quaking Aspen ◽  
Plant Environment

Canopy and edge activity of bats in a quaking aspen (Populus tremuloides) forest

2012 ◽  
Vol 90 (7) ◽  
pp. 798-807 ◽  
Author(s):  
T.W. Pettit ◽  
K.T. Wilkins
Keyword(s):  
Populus Tremuloides ◽  
High Frequency ◽  
Regression Tree ◽  
Low Frequency ◽  
Tree Height ◽  
Quaking Aspen ◽  
Activity Levels ◽  
Forest Canopies ◽  
Bat Activity ◽  
Cart Analysis

Characteristics of edges affect the behavior of species that are active in and near edges. Forest canopies may provide edge-like habitat for bats, though bat response to edge orientation has not been well examined. We sampled bat activity in quaking aspen ( Populus tremuloides Michx.) forest canopies and edges in Heber Valley, Utah, during summer 2009 using Anabat detectors. Categorization and regression tree (CART) analysis of echolocation characteristics (e.g., frequency, duration) identified two guilds based on characteristic frequency (i.e., high- and low-frequency guilds). We used linear regression to compare characteristics of canopy and edge vegetation (e.g., tree height, diameter at breast height) to bat activity levels. Activity levels of high-frequency bats did not respond differentially to edge vegetation; low-frequency bat activity seemed to respond to canopy height. Activity levels of high-frequency bats were significantly greater than low-frequency bats in both edges and canopies. We detected significantly more bat activity in forest edges than in forest canopies, indicating the importance of edges to bats in forests.

Impact of extrafloral nectar availability and plant genotype on ant (Hymenoptera: Formicidae) visitation to quaking aspen (Salicaceae)

2015 ◽  
Vol 148 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Jonathon R. Newman ◽  
Diane Wagner ◽  
Patricia Doak
Keyword(s):  
Populus Tremuloides ◽  
Late Summer ◽  
Early Summer ◽  
Quaking Aspen ◽  
Plant Genotype ◽  
Free Living ◽  
Natural Induction ◽  
Formica Fusca ◽  
Time Of Year ◽  
Nectar Availability

AbstractFor quaking aspen (Populus tremuloides Michaux; Salicaceae) the rate of extrafloral (EF) sugar secretion is increased by defoliation and decreased by drought. Although wholesale blocking of EF nectar has been shown to reduce ant (Hymenoptera: Formicidae) visitation to aspen, the effect of more subtle and realistic variations in nectar availability on ant recruitment is unknown. Working in Alaskan boreal forest (United States of America), we reduced and supplemented EF nectar availability on potted aspen ramets of three genotypes and surveyed visitation by free-living Formica fusca (Linnaeus) (Hymenoptera: Formicidae). Ants were more responsive to a subtle increase in sugar availability than to a decrease. While nectar reduction had no effect on ant visitation, nectar supplementation increased ant visitation to one aspen genotype by 70% during an early summer trial. Average ant visitation to different aspen genotypes varied during the late summer, indicating that aspen genotype can influence attractiveness to ants. We conclude that natural induction of EF secretion in response to herbivory may benefit aspen through improved ant recruitment, though the response is dependent on aspen genotype and time of year. Differences among aspen genets in attractiveness to ants could influence the relative success of genotypes, especially in settings in which aspen regenerates from seed.

The Physiology of Body Weight Regulation: Relevance to the Etiology of Obesity in Children

PEDIATRICS ◽  
1998 ◽  
Vol 101 (Supplement_2) ◽  
pp. 525-539 ◽  
Author(s):  
Michael Rosenbaum ◽  
Rudolph L. Leibel
Keyword(s):  
United States ◽  
Body Weight ◽  
Environmental Factors ◽  
Regulatory System ◽  
The United States ◽  
Genetic Changes ◽  
Adult Body ◽  
Genes Encoding ◽  
Prevalence Of Obesity ◽  
Obesity In Children

The prevalence of obesity in children and adults in the United States has increased by more than 30% over the past decade. Recent studies of the physiology and molecular genetics of obesity in humans have provided evidence that body weight (fat) is regulated. Some of the genes encoding the molecular components of this regulatory system have been isolated from rodents. The increasing prevalence of obesity in the United States apparently represents the interaction of these genes with an environment that encourages a sedentary lifestyle and consumption of calories. The rapid increase in the prevalence of obesity emphasizes the role of environmental factors, because genetic changes could not occur at this rate. Thus, understanding of the relevant genes and how their effects are mediated by environment and development should lead to more effective prophylaxis and therapy of obesity. Although no clear environmental factors have been identified as causative of obesity, the rapid increases in the prevalence of obesity and the seeming voluntary immutability of adult body fatness can be taken as tacit evidence that the pediatric environment can be altered in a way that affects adult body weight.

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