Histoire récente des épidémies de la Tordeuse des bourgeons de l'épinette au nord du lac Saint-Jean (Québec): une analyse dendrochronologique

1990 ◽  
Vol 20 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Hubert Morin ◽  
Danielle Laprise
Keyword(s):  
Population Dynamics ◽  
White Spruce ◽  
Balsam Fir ◽  
Growth Rings ◽  
The Past ◽  
The North ◽  
Host Trees ◽  
Dendrochronological Analysis ◽  
Wildlife Reserve ◽  
Ecological Disturbances

The chronology of spruce budworm (Choristoneurafumiferana (Clem.)) oubreaks for the past 200 years has been reconstructed by dendrochronological analysis of balsam fir (Abiesbalsamea (L.) Mill.) and white spruce (Piceaglauca (Moench) Voss) samples from virgin forests, unaffected by insecticide spraying programs and recently protected against fires in the north and northwest of Lac Saint-Jean. Outbreaks began around 1974, 1944, 1909, and possibly, 1832. They are closely linked with those described in the Laurentide wildlife reserve. The frequency, duration and severity of growth rings suppression associated with outbreaks are similar to those registered during outbreaks in the southern forests, except for the 1974 outbreak, which was shorter and less severe. Other outbreaks registered in southern regions, where the proportion of balsam fir is higher, have reached this region where balsam fir populations are marginal. These results underline the importance of these ecological disturbances in the population dynamics of the host trees of the region.

Inferring sockeye salmon (Oncorhynchus nerka) population dynamics and water quality changes in a stained nursery lake over the past ∼500 years

2004 ◽  
Vol 61 (7) ◽  
pp. 1235-1246 ◽  
Author(s):  
Irene Gregory-Eaves ◽  
Bruce P Finney ◽  
Marianne SV Douglas ◽  
John P Smol
Keyword(s):  
Population Dynamics ◽  
Sockeye Salmon ◽  
Environmental Changes ◽  
Oncorhynchus Nerka ◽  
The Past ◽  
The North ◽  
Salmon Population ◽  
High Concentrations ◽  
The North Pacific ◽  
Multiproxy Approach

Historical and paleolimnological studies have demonstrated that environmental changes in the North Pacific can strongly affect sockeye salmon (Oncorhynchus nerka) abundances. Whether these marine shifts would be influential on sockeye salmon from all lake types, however, has not yet been studied. This study represents the first paleolimnological analysis of past sockeye salmon population dynamics in a stained nursery lake (Packers Lake, Alaska). We adopted a multiproxy approach to determine whether salmon-derived nutrients (inferred from δ15N) would be available for algal uptake (inferred from the diatom species responses) in this stained lake, as high concentrations of humics and iron are known to sequester phosphorus. The strong degree of coherency between δ15N and diatoms, however, suggests that salmon-derived nutrients were bioavailable and enhanced productivity. Overall, our indicators responded to changes in sockeye salmon abundances and volcanic ashfalls over the past ∼500 years. In a section of the core unaffected by tephras (AD ∼1770–1882), our record suggests that the number of sockeye salmon spawners fluctuated widely. Comparison of temporal shifts in inferred sockeye salmon abundances from Packers Lake with other clearwater nursery lakes reveals a broadly consistent pattern, likely influenced by past climatic changes.

POPULATION DENSITY ESTIMATION OF SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE) ON BALSAM FIR AND WHITE SPRUCE FROM 45-CM MID-CROWN BRANCH TIPS

1989 ◽  
Vol 121 (3) ◽  
pp. 267-281 ◽  
Author(s):  
Jacques Régnière ◽  
Timothy J. Lysyk ◽  
Michel Auger
Keyword(s):  
Life Cycle ◽  
Population Density ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Correction Factors ◽  
Insect Development ◽  
Fresh Weight ◽  
Host Trees

AbstractThe 45-cm mid-crown branch tip from balsam fir and white spruce is described in terms of surface area, fresh weight, and bud density. Fresh weight is suggested as the most appropriate unit to express density of all stages of the spruce budworm’s, Choristoneura fumiferana (Clem.), life cycle, particularly for the purposes of comparisons between host species and locations with different foliage conditions.Changes in distribution of the spruce budworm in the crown of balsam fir are documented for all stages of the insect’s life cycle. Correction factors to account for these changes when estimating density on the basis of the 45-cm branch tip sampling unit are given for balsam fir and white spruce.The amount of error in detection of spruce budworm larvae on foliage of both host trees by sampling personnel varied systematically and consistently as a function of insect development. A method to compensate for this type of error is also suggested.

Interrogating the Constitutionality of Federal Character Principle in Nigeria

2018 ◽  
Vol 9 (07) ◽  
pp. 20492-20498
Author(s):  
Aborisade Olasunkanmi ◽  
Christopher Agulanna
Keyword(s):  
Ethnic Groups ◽  
Research Work ◽  
National Unity ◽  
The Past ◽  
The North ◽  
Inhibiting Factors

This work interrogates federal character principle (FCP) in Nigeria. The FCP was designed to fundamentally address the striking features of Nigeria politics of intense struggles for power among the different ethnic groups in the country between the elites from the North and their Southern counterparts and the various segments, but the practice of FCP in Nigeria so far raises curiosity and doubts. Given the outcome of the interrogation, this research work discovered and conclude that federal character has not indeed achieve its objective in the Nigeria, the study finds that Ethnocentrism, Elitism, Mediocrity, Mutual suspicion amongst others accounts for some inhibiting factors of the FCP in Nigeria. Like many other provisions of the Constitution, the Federal Character principle was meant to correct some imbalances experienced in the past, but it has created more problems than it has attempted to solve. Rather than promote national unity, it has disunited Nigerians. There is an urgent need to use more of professionals and result oriented Nigerians to carry out national tasks, than to use unprogressive people due to this "Federal character" issue. Nigeria should be a place where one's track records and qualifications are far greater than just "where they come from" or their lineage if Nigerian truly want to progress.

Colchicum autumnale (Colchicaceae) w okolicach Krakowa – dawne i obecne rozmieszczenie

2019 ◽  
pp. 15-27
Author(s):  
Magdalena Zarzyka-Ryszka
Keyword(s):  
Adjacent Area ◽  
Colchicum Autumnale ◽  
The Past ◽  
The North ◽  
North Eastern ◽  
New Localities ◽  
Present Distribution ◽  
The 19Th Century ◽  
North Eastern Part

The paper describes the past and present distribution of Colchicum autumnale in the vicinity of Cracow, highlights the role of Stanisław Dembosz (who published the first locality of C. autumnale near Igołomia in 1841). Gives information about the occurrence of C. autumnale in Krzeszowice in the 19th century (reported by Bronisław Gustawicz), presents new localities noted in 2012–2014 in meadows in the north-eastern part of the Puszcza Niepołomicka forest and adjacent area (between the Vistula and Raba rivers), and gives a locality found in Cracow in 2005 (no longer extant).

Present Status of the Salmonids Atlantic Salmon and Sea-Trout in the Dutch Part of the River Rhine

1994 ◽  
Vol 29 (3) ◽  
pp. 37-41 ◽  
Author(s):  
W. G. Cazemier
Keyword(s):  
Atlantic Salmon ◽  
Salmo Trutta ◽  
Natural Populations ◽  
River Rhine ◽  
Sea Trout ◽  
The Past ◽  
The North ◽  
Trout Population ◽  
The North Sea ◽  
Heavy Pollution

In the past, the anadromous salmonids, Atlantic salmon (Salmo salar) and sea-trout (Salmo trutta), have formed natural populations in the river Rhine. From the beginning of the nineteenth century onwards, the greater part of the drainage area of the river has been gradually altered from a more or less rural and agricultural area, into a highly industrialised one with subsequent industrialisation, river-engineering and heavy pollution. These developments are considered to be the major cause for the disappearance of the populations of anadromous salmonid fish in the 1950s. The water quality has recovered significantly during the past 25 years. From about 1975 onwards, this process gave rise to a recovery of the anadromous trout population. Results of recent studies of the sea-trout migration pattern are presented. They reveal that nowadays these salmonids can complete their up- and downstream migrations from the North Sea to places, situated at hundreds of kilometres upward the river and vica versa. The numbers of recorded Atlantic salmon and catch locations in inland waters are presented. They show a significant increase since 1989. These phenomena can be understood as promising signs of the recovery of the Rhine aquatic ecosystem.

Uncommon Grounds

2017 ◽  
Author(s):  
Jeffrey Lawrence
Keyword(s):  
American Literature ◽  
Latin American ◽  
Historical Novel ◽  
Latin American Literature ◽  
Historical Account ◽  
American Novel ◽  
Song Of Solomon ◽  
The Past ◽  
The North ◽  
The Us

This chapter turns from a historical account of the development of the US literature of experience and the Latin American literature of reading to a textual analysis of the US and Latin American historical novel. Hemispheric/inter-American scholars often cite William Faulkner’s Absalom, Absalom! (1936), Gabriel García Márquez’s One Hundred Years of Solitude (1967), and Toni Morrison’s Song of Solomon (1977) as exemplifying instances of literary borrowing across the North–South divide. As I demonstrate, however, each of the later texts also realigns its predecessor’s historical imaginary according to the dominant logics of the US and Latin American literary fields. Whereas the American works foreground experiential models of reconstructing the past and conveying knowledge across generations, García Márquez’s Latin American novel presents reading as the fundamental mode of comprehending and transmitting history.

scholarly journals Response Characteristics of Chinese Pine (Pinus tabulaeformis Carr.) Radial Growth to Climate and Drought Variability Reconstruction in Western Liaoning, Northeast China

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 752
Author(s):  
Liu ◽  
Bao ◽  
Bao
Keyword(s):  
Northeast China ◽  
Radial Growth ◽  
Pinus Tabulaeformis ◽  
Western Liaoning ◽  
Chinese Pine ◽  
The Past ◽  
The North ◽  
Pinus Tabulaeformis Carr ◽  
The North Pacific

Chinese pine (Pinus tabulaeformis Carr.) plays an important role in maintaining ecosystem health and stability in western Liaoning Province and the southern Horqin sand land, Northeast China, with benefits including sand fixation and soil erosion. In the context of climate change, developing a better understanding of the relationship between climate factors and growth rates of this species will be extremely valuable in guiding management activities and meeting regional conservation objectives. Here, the results based on two groups of tree-ring samples show that the radial growth of Chinese pine is controlled primarily by water conditions. The longer chronology had the highest correlation coefficient with the January–September mean self-calibrating Palmer Drought Severity Index (scPDSI); therefore, drought variability was reconstructed for the period 1859–2014. Statistical analysis showed that our model explained 41.9% of the variance in radial growth during the 1951–2014 calibration period. Extreme dry and wet events, defined as the criteria of one standard deviation less or greater than the mean value, accounted for 19.9% and 18.6% of the 156-year climate record, respectively. During the past century, the regional hydroclimate experienced significant long-term fluctuations. The dry periods occurred from the early-1900s–1930s and 1980s–2000s, and the wet periods occurred from the 1940s–1970s. The drought reconstruction was consistent with the decreasing trend of the East Asian summer monsoon since the late 1970s. The reconstructed temporal patterns in hydroclimate in western Liaoning were closely related to the large-scale climate drivers in the North Pacific and the tropical equatorial Pacific. The teleconnections were confirmed by spatial correlations between the reconstructed sequence and sea surface temperature (SST) in the North Pacific, as well as the correlations with the Pacific Decadal Oscillation (PDO) and El Niño Southern Oscillation (ENSO) indices. Aerosols played an important role in affecting drought variations over the past several decades. Moisture stress caused by global warming and interdecadal changes in the PDO will have long-term effects on the growth of pines in the study area in the future.

scholarly journals Ensemble models on palaeoclimate to predict India's groundwater challenge

2013 ◽  
Vol 2 (3) ◽  
Author(s):  
Partha Sarathi Datta
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Humid Climate ◽  
Ensemble Models ◽  
North West ◽  
The Past ◽  
The North ◽  
14C Age

In many parts of the world, freshwater crisis is largely due to increasing water consumption and pollution by rapidly growing population and aspirations for economic development, but, ascribed usually to the climate. However, limited understanding and knowledge gaps in the factors controlling climate and uncertainties in the climate models are unable to assess the probable impacts on water availability in tropical regions. In this context, review of ensemble models on δ18O and δD in rainfall and groundwater, 3H- and 14C- ages of groundwater and 14C- age of lakes sediments helped to reconstruct palaeoclimate and long-term recharge in the North-west India; and predict future groundwater challenge. The annual mean temperature trend indicates both warming/cooling in different parts of India in the past and during 1901–2010. Neither the GCMs (Global Climate Models) nor the observational record indicates any significant change/increase in temperature and rainfall over the last century, and climate change during the last 1200 yrs BP. In much of the North-West region, deep groundwater renewal occurred from past humid climate, and shallow groundwater renewal from limited modern recharge over the past decades. To make water management to be more responsive to climate change, the gaps in the science of climate change need to be bridged.

Weather and Outbreaks of the Spruce Budworm in the Province of Quebec from 1939 to 1956

1961 ◽  
Vol 93 (2) ◽  
pp. 118-123 ◽  
Author(s):  
J. G. Pilon ◽  
J. R. Blais
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
The Past ◽  
Forest Regions ◽  
Tree Component ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula

Nearly all forest regions in the Province of Quebec where balsam fir (Abies balsamea (L.) Mill.) is an important tree component have been subjected to severe defoliation by the spruce budworm, Choristoneura fumiferana (Clem.), during the past 20 years. These outbreaks have followed an easterly direction beginning near the Ontario-Quebec border in 1939 and ending in the Gaspé Peninsula in 1958.

Sign in / Sign up

Export Citation Format

Share Document