scholarly journals The effect of an outbreak of the leaf miner Micrurapteryx salicifoliella on the performance of multiple Salix species in interior Alaska

Botany ◽  
2018 ◽  
Vol 96 (8) ◽  
pp. 491-497 ◽  
Author(s):  
Diane Wagner ◽  
Patricia Doak
Keyword(s):  
Stem Elongation ◽  
Leaf Tissue ◽  
Economic Importance ◽  
Leaf Miner ◽  
Leaf Water Content ◽  
Leaf Blotch ◽  
The Past ◽  
Interior Alaska ◽  
Leaf Mining ◽  
General Decline

The genus Salix L. tends to be tolerant of herbivory, but severe outbreaks of herbivorous insects may compromise growth. First documented in Alaska in 1991, the willow leaf blotch miner, Micrurapteryx salicifoliella, is now responsible for frequent and widespread foliar damage to Salix in interior Alaska. We experimentally tested the effect of leaf mining on the performance of four susceptible Salix species across two years of outbreak, and placed the results in the context of a broader survey of leaf mining damage. Across the four species, reduction of leaf mining damage increased average stem elongation, numbers of leaves per shoot, and leaf area. Leaf mining damage was negatively related to leaf water content; a consequence of the leaf miner’s habit of breaching the cuticle on the underside of leaves. Growth deficits due to leaf mining are likely caused by both the loss of leaf tissue to leaf miner feeding and subsequent leaf desiccation. The results are notable in the context of a general decline in productivity in interior Alaska over the past few decades and because the leaf miner impacts Salix species also used by vertebrate browsers of cultural and economic importance, such as moose.

Variable extrafloral nectary expression and its consequences in quaking aspen

2007 ◽  
Vol 85 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Patricia Doak ◽  
Diane Wagner ◽  
Adam Watson
Keyword(s):  
Populus Tremuloides ◽  
Natural Variation ◽  
Leaf Miner ◽  
Quaking Aspen ◽  
Insect Community ◽  
Interior Alaska ◽  
Leaf Mining ◽  
Secretory Glands ◽  
The Relationship ◽  
Phyllocnistis Populiella

Extrafloral nectaries (EFNs) are secretory glands most commonly linked to defensive mutualisms. Both a plant’s need for defense and the strength of defense provided by mutualists will vary with plant condition and local insect community. Thus, the benefit of EFNs may vary spatially and temporally. However, little attention has been paid to natural variation in the presence and abundance of EFNs within and among individuals of the same species. Quaking aspen, Populus tremuloides Michx., bear EFNs on a subset of their leaves. Here, we describe patterns of EFN expression on shoots within ramets, among ramets, and among putative clones in interior Alaska. We also examine the relationship between EFN presence and herbivory by both the very abundant aspen leaf miner, Phyllocnistis populiella Chambers, and less common chewing herbivores. The proportion of leaves bearing EFNs varied from 33% to 87% among distinct aspen stands. Within stands, short (1–2 m height) ramets had higher EFN frequency than their taller (>4 m) neighbors. Patterns of herbivory also differed between short and tall ramets. Compared with leaves without EFNs, those with EFNs suffered less mining damage on short ramets but slightly higher damage on tall ramets. Tall ramets suffered more chewing damage than short ramets, but this damage was unrelated to the presence of EFNs. Our results suggest that variable EFN expression may be explained by variation in the benefits of EFNs. Leaves with EFNs on short ramets benefit through reduction in leaf mining, but this benefit does not extend to tall ramets or other forms of herbivory.

Detection of Prunus necrotic ringspot virus in almond: effect of sampling time on the efficiency of serological and biological indexing methodologies

2002 ◽  
Vol 42 (2) ◽  
pp. 207 ◽  
Author(s):  
T. Bertozzi ◽  
E. Alberts ◽  
M. Sedgley
Keyword(s):  
Stem Elongation ◽  
Leaf Tissue ◽  
Ringspot Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sample Collection ◽  
Local Conditions ◽  
Nursery Stock ◽  
Young Leaves ◽  
Almond Trees ◽  
Prunus Necrotic Ringspot Virus

The reliability of enzyme-linked immunosorbent assay (ELISA) and indexing methodologies for the detection of Prunus necrotic ringspot virus (PNRSV) in almond was assessed under local conditions. Thirteen field-grown almond trees were sampled fortnightly throughout the growing season. Petal and leaf homogenates were used for ELISA and to inoculate herbaceous indicator species, while buds collected from October onwards were budded to woody indicators. ELISA reliably detected PNRSV in petals and young leaves from bud-break until the cessation of stem elongation. While herbaceous indexing was not as reliable as ELISA, woody indicators could differentiate positive from negative samples reliably throughout the testing period. However, for mass screening of foundation plantings, nursery stock and elite germplasm, woody indexing is too costly and slow to give results. The use of ELISA can overcome these limitations but the timing of sample collection is critical. Petal or leaf tissue collected early in the season will yield the most reliable results.

Late Pleistocene and Holocene tephrostratigraphy of interior Alaska and Yukon: Key beds and chronologies over the past 30,000 years

2016 ◽  
Vol 146 ◽  
pp. 28-53 ◽  
Author(s):  
Lauren J. Davies ◽  
Britta J.L. Jensen ◽  
Duane G. Froese ◽  
Kristi L. Wallace
Keyword(s):  
Late Pleistocene ◽  
The Past ◽  
Interior Alaska

scholarly journals Andalusian Organic Farming Plans (2002–2016): Themes, Approaches and Values

2021 ◽  
Vol 13 (6) ◽  
pp. 3570
Author(s):  
José-Francisco Jiménez-Díaz ◽  
Francisco Collado-Campaña
Keyword(s):  
Content Analysis ◽  
Organic Farming ◽  
Semantic Content ◽  
Economic Importance ◽  
Ecological Agriculture ◽  
Political Values ◽  
The Past ◽  
Analysis Methodology ◽  
Semantic Fields ◽  
Spanish Region

Organic farming in the Spanish region of Andalusia has acquired great socio-economic importance over the past decades. The purpose of this article is to study the themes, approaches, and socio-political values pertaining to ecological agriculture addressed in the Andalusian plans for organic farming (2002–2016). The contents of these plans have not been systematically studied before. From a descriptive and qualitative perspective, the authors present and classify the main themes addressed in those plans and show the socio-political approaches and values that underpin the plans. A thematic and semantic content analysis methodology is applied to the plans and sections addressing various objectives, measures, and actions. A theoretical-qualitative sampling is developed, and 109 keywords are selected for content analysis. This analysis allows us to detect numerous themes pertaining to ecological agriculture and to classify them into six semantic fields linked to various approaches and values promoted by the Andalusian autonomous administration. Therefore, this research focuses on changing perspectives of organic farming developed by the administration and the agents involved in the plans. The authors conclude that the diverse actors have prioritized a productivist–technocratic approach to ecological agriculture, to the detriment of an approach centered on sustainable and agroecological local communities.

The Future Of Master Limited Partnerships

2014 ◽  
Vol 30 (5) ◽  
pp. 1492
Author(s):  
Charles F. Beauchamp
Keyword(s):  
Institutional Investors ◽  
Economic Importance ◽  
Low Risk ◽  
The Past ◽  
Size Number ◽  
The Future ◽  
New Entrants ◽  
Investment Portfolios ◽  
Limited Partnerships ◽  
Business Structure

<p>Master limited partnerships have grown in size, number, and economic importance over the past fifteen years. They now represent a stable and healthy component of many investment portfolios. MLPs have generated impressive risk-adjusted performance compared to that of other equity investments. This performance is the result of their fee-based, low risk business structure that produces a steady cash distribution to investors. The future to these traditional MLPs and similar new entrants is quite positive. However, new entrants that potentially deviate from this successful operating structure are entering the MLP market. This raises major questions regarding the sustainability of these firms as MLPs. This study examines the future of MLP markets within the context of traditional and non-traditional new entrants. Furthermore, the emergence of institutional investors on MLP markets is discussed.</p>

scholarly journals Global economic value of shark ecotourism: implications for conservation

Oryx ◽  
2013 ◽  
Vol 47 (3) ◽  
pp. 381-388 ◽  
Author(s):  
Andrés M. Cisneros-Montemayor ◽  
Michele Barnes-Mauthe ◽  
Dalal Al-Abdulrazzak ◽  
Estrella Navarro-Holm ◽  
U. Rashid Sumaila
Keyword(s):  
Analytical Approach ◽  
Economic Value ◽  
Economic Benefits ◽  
Economic Importance ◽  
The Past ◽  
The World ◽  
Shark Conservation ◽  
Shark Fisheries

AbstractAmid declining shark populations because of overfishing, a burgeoning shark watching industry, already well established in some locations, generates benefits from shark protection. We compile reported economic benefits at shark watching locations and use a meta-analytical approach to estimate benefits at sites without available data. Results suggest that, globally, c. 590,000 shark watchers expend > USD 314 million per year, directly supporting 10,000 jobs. By comparison, the landed value of global shark fisheries is currently c. USD 630 million and has been in decline for most of the past decade. Based on current observed trends, numbers of shark watchers could more than double within the next 20 years, generating > USD 780 million in tourist expenditures around the world. This supports optimistic projections at new sites, including those in an increasing number of shark sanctuaries established primarily for shark conservation and enacted in recognition of the ecological and economic importance of living sharks.

scholarly journals A LIST OF CALIFORNIA APHIDIDÆ

1903 ◽  
Vol 35 (9) ◽  
pp. 247-254 ◽  
Author(s):  
Warren. T. Clarke
Keyword(s):  
Economic Importance ◽  
The Past ◽  
Systematic List

Our knowledge of the group Aphididæ in California has been limited in the past to certain forms that were of economic importance in their relations to cultivated crops. No systematic list of these interesting insects has heretofore been attempted in this region, and this has not been due to any lack of material, for the varying conditions of climate here seem to be particularly favorable to them.

United States Foreign Policy in Southern Africa: Third-World Perspectives

1983 ◽  
Vol 21 (4) ◽  
pp. 587-603 ◽  
Author(s):  
Davidson Nicol
Keyword(s):  
United States ◽  
Human Rights ◽  
Reagan Administration ◽  
Third World ◽  
The United States ◽  
Economic Importance ◽  
United States Foreign Policy ◽  
Multilateral Aid ◽  
The Past ◽  
The Government

The past decade has seen an increase in the scope of relationships, both political and economic, between Africa and the United States. These vary with the complexion of the government in power, though some would say that this was more in emphasis than in substance, others definitely not. It is felt by many Africans, nevertheless, that the Carter Administration's emphasis on human rights has now been downgraded by the present Reagan Administration and that, instead, the geopolitics of U.S.–U.S.S.R. rivalry, and the economic importance of developing the private sector at the expense of bilateral or multilateral aid, have been moved to the fore.

‘B.M.G. … “Baldwin (this time) must go!”’: The frustrations of Opposition, June 1929 – July 1931

1995 ◽  
Vol 5 ◽  
pp. 331-375
Keyword(s):  
House Of Commons ◽  
The West ◽  
Difficult Situation ◽  
The Past ◽  
General Decline ◽  
West Midlands ◽  
Electoral Defeat ◽  
Foreign Office ◽  
Safety First

Although electoral defeat and loss of office can never be a welcome experience, in June 1929 the pain of Ansten Chamberlain's transition to the Opposition benches was temporarily alleviated by a sense of personal relief at his continued presence in the House of Commons at all. After the 1924 election he had confessed that the position in his West Birmingham constituency made him ‘very anxious’. Predicting that ‘it will be a suffer fight next time’ he had thus resolved to ‘try somehow to see more of them’. Four and a half years at the Foreign Office did nothing to help him redeem that pledge. By 1929 Chamberlain confronted not only an increasingly difficult situation in West Birmingham where the slums and poverty had given him cause to wonder at a Conservative victory in the past, but also the general electoral disillusion with the Baldwin's government's promise of ‘Safety First’ and their failure to revive the economy. Although never an active or particularly diligent constituency MP, in 1929 Chamberlain almost fell victim to a more general decline in Conservative support within the West Midlands. Since 1886 the Conservatives had never lost more than one Birmingham seat. In 1929 Labour were in confident mood and took no less than six of the twelve seats. After the canvass returns, Chamberlain had warned his family to expect defeat and during the two counts he confessed himself to be ‘in a very philosophic mood’. In the event, he scraped in by just 43 votes in a seat held continuously by a Chamberlain for almost half a century.

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