Life history patterns and trophic ecology of Trichoptera in two Alaskan (U.S.A.) subarctic streams

1988 ◽  
Vol 66 (6) ◽  
pp. 1258-1265 ◽  
Author(s):  
John G. Irons III
Keyword(s):  
Life History ◽  
Boreal Forest ◽  
Life Histories ◽  
Trophic Ecology ◽  
Similar Species ◽  
Allochthonous Input ◽  
Interior Alaska ◽  
West Fork ◽  
Life History Patterns ◽  
Periphyton Biomass

Monument Creek and West Fork, two interior Alaskan streams that are tributaries of the Chena River, are characterized by low water temperatures, low allochthonous input and periphyton biomass, and lengthy ice cover. Nine species of Trichoptera were found: Rhyacophila vofixa (Rhyacophilidae), Glossosoma verdona, Glossosoma alascense (Glossosomatidae), Brachycentrus americanus (Brachycentridae), Hydatophylax variabilis, Ecclisomyia conspersa, Onocosmoecus unicolor, Chyranda centralis, and Apatania crymophila (Limnephilidae). There were four shredders, three scrapers, one omnivore, and one predator. Within the shredder and scraper guilds, species had partially overlapping univoltine life histories, perhaps allowing functionally similar species to use the same food resources. The trichopteran fauna of interior Alaska seems to be composed of species typical of boreal forest, with arctic, western montane, and Siberian influences.

Life Histories of Charophytes from Permanent and Temporary Wetlands in Eastern Australia

1999 ◽  
Vol 47 (3) ◽  
pp. 383 ◽  
Author(s):  
Michelle T. Casanova ◽  
Margaret A. Brock
Keyword(s):  
Life History ◽  
Sexual Reproduction ◽  
Vegetative Growth ◽  
Life Histories ◽  
Distribution Patterns ◽  
Reproductive Organs ◽  
Annual Species ◽  
Large Numbers ◽  
Eastern Australia ◽  
Life History Patterns

The results of an experiment on the demography of charophytes in permanent and temporary sites in two wetlands are outlined and the charophytes that germinated and established are described in relation to their life histories. Three life-history patterns are represented. First, Monoecious annual species germinate easily and rapidly after inundation, they grow quickly and initiate sexual reproduction at the expense of vegetative expansion, produce relatively few, large oospores and die in winter. Second, Dioecious annual species are slower to germinate than Monoecious annuals, they grow more slowly, but also initiate sexual reproduction early in life. They usually produce large numbers of small oospores and die in unfavourable seasons. Both winter-growing and summer-growing Dioecious annuals were represented in experiments. Third, Dioecious perennials germinate after a lag time and establishment; vegetative growth and expansion takes place early in spring. Reproduction in Dioecious perennials is stimulated by increasing water temperatures and other environmental cues. Vegetative reproductive organs are produced in autumn and individual shoots can be very long-lived. Life-history parameters such as germination requirements, establishment requirements and timing of vegetative growth and reproduction can be important in determining the distribution patterns in charophytes.

Temporal–spatial variation in white-tailed prairie dog demography and life histories in Wyoming

1989 ◽  
Vol 67 (2) ◽  
pp. 343-349 ◽  
Author(s):  
George E. Menkens Jr. ◽  
Stanley H. Anderson
Keyword(s):  
Life History ◽  
Population Density ◽  
Body Mass ◽  
Life Histories ◽  
Life History Traits ◽  
Prairie Dogs ◽  
Similar Species ◽  
Prairie Dog ◽  
Adult Body Mass ◽  
Habitat Variation

Variation in population density and life history traits were studied in six white-tailed prairie dog (Cynomys leucurus) populations in Wyoming using mark – recapture techniques. All life history traits (except juvenile sex ratios) and population density exhibited significant variation within towns between years and among towns in the same year. Temporal and spatial habitat variation significantly affects juvenile body mass but not adult body mass, which, in turn, results in the observed variation in life history traits. We conclude that white-tailed prairie dogs are dynamic reproducers and that their population age distributions are neither stable nor stationary. Use of life tables to study life history patterns of this species or of similar species would be inappropriate because of a failure to meet a basic assumption of life table models.

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.

scholarly journals Assessing Wildfire Burn Severity and Its Relationship with Environmental Factors: A Case Study in Interior Alaska Boreal Forest

2021 ◽  
Vol 13 (10) ◽  
pp. 1966
Author(s):  
Christopher W Smith ◽  
Santosh K Panda ◽  
Uma S Bhatt ◽  
Franz J Meyer ◽  
Anushree Badola ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Ground Truth ◽  
Burn Severity ◽  
Classification Methods ◽  
Spectral Indices ◽  
Ground Truth Data ◽  
Burn Scar ◽  
Interior Alaska ◽  
Remote Sensing Methods ◽  
The Relationship

In recent years, there have been rapid improvements in both remote sensing methods and satellite image availability that have the potential to massively improve burn severity assessments of the Alaskan boreal forest. In this study, we utilized recent pre- and post-fire Sentinel-2 satellite imagery of the 2019 Nugget Creek and Shovel Creek burn scars located in Interior Alaska to both assess burn severity across the burn scars and test the effectiveness of several remote sensing methods for generating accurate map products: Normalized Difference Vegetation Index (NDVI), Normalized Burn Ratio (NBR), and Random Forest (RF) and Support Vector Machine (SVM) supervised classification. We used 52 Composite Burn Index (CBI) plots from the Shovel Creek burn scar and 28 from the Nugget Creek burn scar for training classifiers and product validation. For the Shovel Creek burn scar, the RF and SVM machine learning (ML) classification methods outperformed the traditional spectral indices that use linear regression to separate burn severity classes (RF and SVM accuracy, 83.33%, versus NBR accuracy, 73.08%). However, for the Nugget Creek burn scar, the NDVI product (accuracy: 96%) outperformed the other indices and ML classifiers. In this study, we demonstrated that when sufficient ground truth data is available, the ML classifiers can be very effective for reliable mapping of burn severity in the Alaskan boreal forest. Since the performance of ML classifiers are dependent on the quantity of ground truth data, when sufficient ground truth data is available, the ML classification methods would be better at assessing burn severity, whereas with limited ground truth data the traditional spectral indices would be better suited. We also looked at the relationship between burn severity, fuel type, and topography (aspect and slope) and found that the relationship is site-dependent.

scholarly journals Classical soloists’ life histories and the music conservatoire

2021 ◽  
pp. 025576142199115
Author(s):  
Tim Palmer ◽  
David Baker
Keyword(s):  
Higher Education ◽  
Life History ◽  
Life Histories ◽  
Qualitative Data ◽  
Classical Music ◽  
Loss Of Autonomy ◽  
Cultural Interest ◽  
Concert Pianist ◽  
Analytic Induction ◽  
Musical Excellence

This article explores the life histories of virtuoso classical music soloists with particular reference to conservatoire provision. Detailed life-history interviews were conducted with six virtuosi between May 2018 and January 2019. These participants were three singers, two cellists and a concert pianist. Resultant qualitative data were stored in an NVivo software database and understood through a process of analytic induction. Key findings spotlight the significance of Higher Education, a connection between broad creative and cultural interest and musical excellence, and a significant role for conservatoires in diversifying their training and easing transition into the career. The soloists also warned of dangers relating to controlling teachers, loss of autonomy and a need to convey their career realities to students.

Inadvertent Exemplars: Life History Portraits of Two Socially Just Principals

2012 ◽  
Vol 22 (1) ◽  
pp. 79-115 ◽  
Author(s):  
Martin Scanlan
Keyword(s):  
Social Justice ◽  
Life History ◽  
Elementary Schools ◽  
Middle Class ◽  
Life Histories ◽  
Public Elementary Schools ◽  
White Middle Class ◽  
English Speaking ◽  
Native English Speaking

This study creates life history portraits of two White middle-class native-English-speaking principals demonstrating commitments to social justice in their work in public elementary schools serving disproportionately high populations of students who are marginalized by poverty, race, and linguistic heritage. Through self-reported life histories of these principals, I create portraits that illustrate how these practitioners draw motivation, commitment, and sustenance in varied, complicated, and at times contradictory ways.

A comparative study of the life histories of Nematodirus battus and N. filicollis, nematode parasites of sheep

Parasitology ◽  
1959 ◽  
Vol 49 (3-4) ◽  
pp. 374-386 ◽  
Author(s):  
R. J. Thomas
Keyword(s):  
Life History ◽  
Intestinal Mucosa ◽  
Related Species ◽  
Life Histories ◽  
Basic Pattern ◽  
Culture Methods ◽  
Closely Related Species ◽  
Nematode Parasites ◽  
History Of ◽  
Comparative Description

1. The life history of N. battus is described, and a comparative description of the life history of N. filicollis is given.2. The life histories of these two species are compared with those of N. spathiger and N. helvetianus, two closely related species, and are shown to follow the same basic pattern, with minor variations in timing which appear to be specific in nature, and not related to differences in culture methods or host species.3. The pathogenesis of Nematodirus species is discussed and related to the migration of larvae into the intestinal mucosa during development.

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