Home About us Contact
|
Home About us Contact | ||
|
|
||
Newfoundland
Selected AbstractsDIVERSIFYING COEVOLUTION BETWEEN CROSSBILLS AND BLACK SPRUCE ON NEWFOUNDLANDEVOLUTION, Issue 8 2002Thomas L. Parchman Abstract Coevolution is increasingly recognized as an important process structuring geographic variation in the form of selection for many populations. Here we consider the importance of a geographic mosaic of coevolution to patterns of crossbill (Loxia) diversity in the northern boreal forests of North America. We examine the relationships between geographic variation in cone morphology, bill morphology, and feeding performance to test the hypothesis that, in the absence of red squirrels (Tamiasciurus hudsonicus), black spruce (Picea mariana) has lost seed defenses directed at Tamiasciurus and that red crossbills (L. curvirostra) and black spruce have coevolved in an evolutionary arms race. Comparisons of cone morphology and several indirect lines of evidence suggest that black spruce has evolved defenses in response to Tamiasciurus on mainland North America but has lost these defenses on Newfoundland. Cone traits that deter crossbills, including thicker scales that require larger forces to separate, are elevated in black spruce on Newfoundland, and larger billed crossbills have higher feeding performances than smaller billed crossbills on black spruce cones from Newfoundland. These results imply that the large bill of the Newfoundland crossbill (L. c. percna) evolved as an adaptation to the elevated cone defenses on Newfoundland and that crossbills and black spruce coevolved in an evolutionary arms race on Newfoundland during the last 9000 years since glaciers retreated. On the mainland where black spruce is not as well defended against crossbills, the small-billed white-winged crossbill (L. leucoptera leucoptera) is more efficient and specializes on seeds in the partially closed cones. Finally, reciprocal adaptations between crossbills and conifers are replicated in black spruce and Rocky Mountain lodgepole pine (Pinus contorta ssp. latifolia), with coevolution most pronounced in isolated populations where Tamiasciurus are absent as a competitor. This study further supports the role of Tamiasciurus in determining the selection mosaic for crossbills and suggests that a geographic mosaic of coevolution has been a prominent factor underlying the diversification of North American crossbills. [source] Interactive effects of distance and matrix on the movements of a peatland dragonflyECOGRAPHY, Issue 5 2009Krista S. Chin We conducted a mark,release,recapture survey of a peatland dragonfly (Leucorrhinia hudsonica) in each of two years (2002; 2003) in a harvested forest landscape in western Newfoundland, Canada. The odds of an individual male moving between peatlands was influenced by both the distance between peatlands and the type of intervening habitat (the matrix). Specifically, at meso scales (>700,m) there was a positive effect of the amount of cut matrix between peatlands on the odds of moving, but at fine scales (<700,m) there was the opposite effect; proportionally fewer individuals moved between peatlands. The odds of moving out of a peatland decreased as the surface area of water in the peatland increased. Multi-state mark,recapture models showed that the daily probability of a male moving between any two peatlands was 1.9% in 2002 and 6.9% in 2003 (n=1527 and 1280 marked individuals). The results suggest that additional empirical studies that directly measure patterns of movement with respect to landscape structure at multiple spatial scales in other taxa and situations are needed in order to uncover other possible non-linear changes in behavior. [source] The effects of fluvial processes and habitat heterogeneity on distribution, growth and densities of juvenile Atlantic salmon (Salmo salar L.), with consequences on abundance of the adult fishECOLOGY OF FRESHWATER FISH, Issue 4 2002R. J. Gibson Abstract,,,The required freshwater habitats of juvenile Atlantic salmon (Salmo salar) are, in general, well known, but vary in quality, related to interacting effects of several variables, which may depend on different parts of a river system. Examples are given of ranges of densities and growth that can be found at various sites in eastern Canada, illustrating the biological and physico-chemical factors affecting production of juvenile salmon. Relative growth rates can indicate habitat quality and population densities. Salmon parr have negative effects on brook trout in riffle habitats. The effects of migrations within the river and of changes with stream succession on juvenile salmon production are illustrated with examples from a Newfoundland river. Migration of age-classes can be quantified from ,self-thinning' curves. Lakes have enhancing effects on downstream fluvial habitats, and, at least in Newfoundland, and probably in many boreal areas, the lacustrine proportion of the basin can be used as an index for deriving estimates of required spawning escapement. The factors described should be taken into account for more refined estimates of river production and management of the salmon resource. [source] A meta-analysis of marijuana, cocaine and opiate toxicology study findings among homicide victimsADDICTION, Issue 7 2009Joseph B. Kuhns ABSTRACT Aim To synthesize the results of marijuana, cocaine and opiate drug toxicology studies of homicide victims and examine variation in results across person and setting characteristics. Methods A meta-analysis of 18 independent studies identified from an extensive review of 239 published articles that met the inclusion criteria of reporting marijuana, cocaine and/or opiate toxicology test results for homicide victims. A total of 28 868 toxicology test results derived from 30 482 homicide victims across five countries were examined. Results On average, 6% of homicide victims tested positive for marijuana, 11% tested positive for cocaine, and 5% tested positive for opiates. The proportion of homicide victims testing positive for illicit drugs has increased over time. Age had a strong curvilinear relationship with toxicology test results, but gender differences were not apparent. Hispanic and African American homicide victims were more likely to test positive for cocaine; Caucasians were most likely to test positive for opiates. Cocaine use appeared to be related to increased risk of death from a firearm and was a greater risk factor for violent victimization in the United States than in Newfoundland and Scandinavia. Conclusion There are relatively few studies of illicit drug toxicology reports from homicide victims that allow for cross-cultural comparisons. This study provides a basis for comparing future local toxicology test results to estimates from existing research. [source] DIVERSIFYING COEVOLUTION BETWEEN CROSSBILLS AND BLACK SPRUCE ON NEWFOUNDLANDEVOLUTION, Issue 8 2002Thomas L. Parchman Abstract Coevolution is increasingly recognized as an important process structuring geographic variation in the form of selection for many populations. Here we consider the importance of a geographic mosaic of coevolution to patterns of crossbill (Loxia) diversity in the northern boreal forests of North America. We examine the relationships between geographic variation in cone morphology, bill morphology, and feeding performance to test the hypothesis that, in the absence of red squirrels (Tamiasciurus hudsonicus), black spruce (Picea mariana) has lost seed defenses directed at Tamiasciurus and that red crossbills (L. curvirostra) and black spruce have coevolved in an evolutionary arms race. Comparisons of cone morphology and several indirect lines of evidence suggest that black spruce has evolved defenses in response to Tamiasciurus on mainland North America but has lost these defenses on Newfoundland. Cone traits that deter crossbills, including thicker scales that require larger forces to separate, are elevated in black spruce on Newfoundland, and larger billed crossbills have higher feeding performances than smaller billed crossbills on black spruce cones from Newfoundland. These results imply that the large bill of the Newfoundland crossbill (L. c. percna) evolved as an adaptation to the elevated cone defenses on Newfoundland and that crossbills and black spruce coevolved in an evolutionary arms race on Newfoundland during the last 9000 years since glaciers retreated. On the mainland where black spruce is not as well defended against crossbills, the small-billed white-winged crossbill (L. leucoptera leucoptera) is more efficient and specializes on seeds in the partially closed cones. Finally, reciprocal adaptations between crossbills and conifers are replicated in black spruce and Rocky Mountain lodgepole pine (Pinus contorta ssp. latifolia), with coevolution most pronounced in isolated populations where Tamiasciurus are absent as a competitor. This study further supports the role of Tamiasciurus in determining the selection mosaic for crossbills and suggests that a geographic mosaic of coevolution has been a prominent factor underlying the diversification of North American crossbills. [source] Trophic role of Atlantic cod in the ecosystemFISH AND FISHERIES, Issue 1 2009Jason S. Link Abstract As the world's oceans continue to undergo drastic changes, understanding the role of key species therein will become increasingly important. To explore the role of Atlantic cod (Gadus morhua Gadidae) in the ecosystem, we reviewed biological interactions between cod and its prey, predators and competitors within six ecosystems taken from a broad geographic range: three are cod-capelin (Mallotus villosus Osmeridae) systems towards cod's northern Atlantic limit (Barents Sea, Iceland and Newfoundland,Labrador), two are more diverse systems towards the southern end of the range (North Sea and Georges Bank,Gulf of Maine), and one is a species-poor system with an unusual physical and biotic environment (Baltic Sea). We attempt a synthesis of the role of cod in these six ecosystems and speculate on how it might change in response to a variety of influences, particularly climate change, in a fashion that may apply to a wide range of species. We find cod prey, predators and competitors functionally similar in all six ecosystems. Conversely, we estimate different magnitudes for the role of cod in an ecosystem, with consequently different effects on cod, their prey and predator populations. Fishing has generally diminished the ecological role of cod. What remains unclear is how additional climate variability will alter cod stocks, and thus its role in the ecosystem. [source] Spatial and temporal trends in abundance of Atlantic salmon, Salmo salar, in Newfoundland with emphasis on impacts of the 1992 closure of the commercial fisheryFISHERIES MANAGEMENT & ECOLOGY, Issue 6 2004J. B. Dempson Abstract Closure of the Newfoundland commercial Atlantic salmon, Salmo salar L., fishery in 1992 was the most restrictive measure introduced to help rebuild depressed local stocks of salmon. Here, the effects of the closure are evaluated by analysing trends in abundance since 1984, and estimates of survival in both freshwater and marine environments derived from enumeration of salmon at fish counting facilities. While freshwater production of smolts generally has been maintained, marine survival rates remain low (2,10%), and highly variable. Overall, total stock size differs little from that prior to the closure of the commercial salmon fishery. Spawning escapements have increased by a factor of 2 or 3 in some rivers, but in other areas total returns are lower on average than those prior to the fishery closure. Factors other than exploitation are contributing to lack of stock recovery, resulting in continued conservation concerns. [source] Uncertainty about estimating total returns of Atlantic salmon, Salmo salar to the Gander River, Newfoundland, Canada, evaluated using a fish counting fenceFISHERIES MANAGEMENT & ECOLOGY, Issue 1 2003M. F. O'Connell Abstract ,For a number of rivers in Newfoundland, Atlantic salmon, Salmo salar L., is managed in relation to river-specific conservation spawning requirements. One such river is the Gander River, where between 1989 and 1999, the escapement of Atlantic salmon, a major factor in assessing the status of stock, was determined using a fish counting fence. In 2000, the counting fence was discontinued and alternative means of calculating total returns were explored. Regression and simulation methods, using relationships between total returns and salmon counts at an upstream tributary during 1989,99, formed the basis for estimates of returns for 2000, and the uncertainty around estimates. The accuracy of methods is evaluated by retrospective comparisons with actual total returns between 1989 and 1999. Estimates of total returns deviated from the actual by as much as 50,60%, depending on the method. Management implications of the approach are discussed. [source] Effects of catch and release angling on Atlantic salmon, Salmo salar L., of the Conne River, NewfoundlandFISHERIES MANAGEMENT & ECOLOGY, Issue 3 2002J. B. DEMPSON The effects of catch and release angling on survival of Atlantic salmon, Salmo salar L., at Conne River, Newfoundland, were investigated by retaining angled (n=49; experimental group) and trap-caught (n=20; control group) fish in holding cages for up to 40 days. Samples were obtained from 8 June to 4 July, 2000, and partitioned among four water temperature strata. Apart from not being angled, control fish were handled, tagged, and transferred to holding cages in a manner similar to angled salmon. Water temperatures and discharge were monitored throughout the duration of the study. Overall, 8.2% of salmon caught and released died, but 12% died among salmon angled in water temperatures , 17.9 °C. No control fish died. There were no significant differences in time associated with angling, exposure to air, tagging, transfer to holding cages, nor total handling time between salmon that survived vs. those that died. Results of the study should encourage managers to continue to use catch and release as a viable tool in the management of Atlantic salmon stocks. [source] Shrimp (Pandalus borealis) growth and timing of the spring phytoplankton bloom on the Newfoundland,Labrador ShelfFISHERIES OCEANOGRAPHY, Issue 2 2007C. FUENTES-YACO Abstract We examined latitudinal and temporal changes in the availability of food for young shrimp (Pandalus borealis) on the Newfoundland,Labrador Shelf, using a suite of quantitative characteristics of the spring phytoplankton bloom determined from satellite ocean colour data, including bloom initiation time, maximum chlorophyll concentration, timing of the maximum, and bloom duration. We found significant correlations between bloom intensity, timing, and the size of young shrimp. The results are discussed in relation to the observation that, since the early 1990s, carapace lengths of shrimp have been decreasing in many Northwest Atlantic stocks. [source] Thermal habitat experienced by Atlantic salmon (Salmo salar L.) kelts in coastal Newfoundland watersFISHERIES OCEANOGRAPHY, Issue 1 2004David G. Reddin Abstract Thermal habitat was recorded by data storage tags (DSTs) applied to Atlantic salmon (Salmo salar L.) kelts during their seaward migration in the spring of 1998 at enumeration facilities in Highlands River, Humber River, Western Arm Brook, and Campbellton River, Newfoundland. In total, 139 DSTs were applied and data were downloaded from eleven of the recovered tags. The recovered tags had been applied at Highlands, Campbellton and Western Arm rivers and recovered in the coastal waters of Newfoundland and Québec and at the enumeration facilities at Highlands and Campbellton rivers. Water temperatures experienced by the fish were recorded for periods of 62,118 days at resolutions of 15,30 min. The data from the sea record on the DSTs were analysed for temperature patterns in relation to migration behaviour and diurnal movement of the fish. A variety of patterns were exhibited on the temperature records suggesting that the fish were behaving in various ways at different times. For Campbellton and Highlands fish over the course of some 24 h periods, night-time temperatures changed little and were among the highest daily temperatures experienced by the fish, whereas daytime temperatures often showed dramatic and frequent shifts in temperature presumably as the fish rapidly and frequently changed depth. For the Western Arm Brook fish, rapid fluctuations in temperature occurred sometimes during the day and night without a consistent diurnal pattern. We also considered large-scale aspects of the data by examining oceanographic conditions in relation to the temperatures recorded by the tags. [source] A spatially explicit study of prey,predator interactions in larval fish: assessing the influence of food and predator abundance on larval growth and survivalFISHERIES OCEANOGRAPHY, Issue 1 2003P. Pepin Abstract We apply a coupled biophysical model to reconstruct the environmental history of larval radiated shanny in Conception Bay, Newfoundland. Data on the larvae, their prey and predators were collected during a 2-week period. Our goal was to determine whether environmentally explicit information could be used to infer the characteristics of individual larvae that are most likely to survive. Backward drift reconstruction was used to assess the influence of variations in the feeding environment on changes in the growth rates of individual larvae. Forward drift projections were used to assess the impact of predators on mortality rates as well as the cumulative density distribution of growth rates in the population of larvae in different areas of the bay. There was relatively little influence of current feeding conditions on increment widths. Patterns of selective mortality indicate that fast-growing individuals suffered higher mortality rates, suggesting they were growing into a predator's prey field. However, the mortality rates appeared to increase with decreasing predator abundance, based on the drift reconstructions. The relationship of growth and mortality with environmental conditions suggests that short-term, small-scale variations in environmental history may be difficult to describe accurately in this relatively small system (,1000 km2). [source] The influence of temperature on advective loss of Atlantic cod (Gadus morhua) eggs from the inshore environmentFISHERIES OCEANOGRAPHY, Issue 4 2001Ian R. Bradbury We use a simple model of temperature-dependent egg development and mortality to develop several hypotheses concerning the effect of temperature on the occurrence of eggs of Atlantic cod, Gadus morhua, in Placentia Bay, Newfoundland. Predictions from this exploratory model were tested through a series of synoptic ichthyoplankton surveys throughout spawning and postspawning periods during 1997 and 1998. Although several egg mortality relationships were explored through the simulation, a constant mortality rate best represented the pattern observed in the two years of data. Peaks in late stage egg densities occurred in August of both 1997 and 1998 and were apparently decoupled from egg production peaks in April. We observed a decrease in mortality and the distance dispersed during egg development with increases in water temperature. We suggest that the effects of predation are small relative to the advective effects within this system, and that the interaction between advection and temperature-dependent vital rates of eggs may have dramatic consequences for coastal retention of propagules produced by inshore spawning events. [source] Crustal structure of the Newfoundland rifted continental margin from constrained 3-D gravity inversionGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2007J. Kim Welford ABSTRACT The rifting history of the Atlantic continental margin of Newfoundland is very complex and so far has been investigated at the crustal scale primarily with the use of 2-D seismic surveys. While informative, the results generated from these surveys cannot easily be interpreted in a regional sense due to their sparse sampling of the margin. A 3-D gravity inversion of the free air data over the Newfoundland margin allows us to generate a 3-D density anomaly model that can be compared with the seismic results and used to gain insight into regions lacking seismic coverage. Results of the gravity inversion show good correspondence with Moho depths from seismic results. A shallowing of the Moho to 12 km depth is resolved on the shelf at the northern edge of the Grand Banks, in a region poorly sampled by other methods. Comparisons between sediment thickness and crustal thickness show deviations from local isostatic compensation in locations which correlate with faults and rifting trends. Such insights must act as constraints for future palaeoreconstructions of North Atlantic rifting. [source] Local- to continental-scale variation in the richness and composition of an aquatic food webGLOBAL ECOLOGY, Issue 5 2010Hannah L. Buckley ABSTRACT Aim, We investigated patterns of species richness and composition of the aquatic food web found in the liquid-filled leaves of the North American purple pitcher plant, Sarracenia purpurea (Sarraceniaceae), from local to continental scales. Location, We sampled 20 pitcher-plant communities at each of 39 sites spanning the geographic range of S. purpurea, from northern Florida to Newfoundland and westward to eastern British Columbia. Methods, Environmental predictors of variation in species composition and species richness were measured at two different spatial scales: among pitchers within sites and among sites. Hierarchical Bayesian models were used to examine correlates and similarities of species richness and abundance within and among sites. Results, Ninety-two taxa of arthropods, protozoa and bacteria were identified in the 780 pitcher samples. The variation in the species composition of this multi-trophic level community across the broad geographic range of the host plant was lower than the variation among pitchers within host-plant populations. Variation among food webs in richness and composition was related to climate, pore-water chemistry, pitcher-plant morphology and leaf age. Variation in the abundance of the five most common invertebrates was also strongly related to pitcher morphology and site-specific climatic and other environmental variables. Main conclusions, The surprising result that these communities are more variable within their host-plant populations than across North America suggests that the food web in S. purpurea leaves consists of two groups of species: (1) a core group of mostly obligate pitcher-plant residents that have evolved strong requirements for the host plant and that co-occur consistently across North America, and (2) a larger set of relatively uncommon, generalist taxa that co-occur patchily. [source] Variability of the impact of El Niño,southern oscillation on sea-level pressure anomalies over the North Atlantic in January to March (1874,1996)INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 13 2003I. Gouirand Abstract Sea-level pressure (SLP) anomalies over the North Atlantic and European (NAE) sector (25,70°N, 100°W,50°E) and over a larger domain encompassing the entire North Pacific domain are studied to demonstrate that SLP anomalies (SLPAs) during boreal winter (January,March) vary widely between years characterized by the same El Niño,southern oscillation (ENSO) phase. The typical cold ENSO signal tends to be more stable than the warm one during the 1874,1996 period. The typical cold ENSO pattern (e.g. positive SLPA south of 55°N across the North Atlantic and negative SLPA in the northern North Atlantic) is similar to the positive phase of the North Atlantic oscillation (NAO) and occurs throughout the 20th century, except during the 1950s and 1960s when the basinwide westerlies are particularly slow. On the contrary, the typical warm ENSO pattern (e.g. positive SLPA from central Canada to Scandinavia and negative SLPA from the southeastern USA to central Europe, corresponding to the negative phase of the NAO) occurs mainly from 1930 to 1970. Another robust warm ENSO pattern is associated with a large positive (negative) SLPA between Newfoundland and western Europe (between Greenland and Scandinavia), and occurs mainly at the beginning and the end of the 20th century when the basinwide North Atlantic westerlies are strengthened. All these patterns stay statistically significant when the multi-decadal variability is removed from the North Atlantic SLPA. It is shown that the low-frequency variability of the north tropical Atlantic sea-surface temperature anomalies could exert a modulating effect on the ENSO teleconnection. NAE SLPAs tend to be strong during warm (cold) ENSO winters and consistent with a negative (positive) phase of the NAO when the north tropical Atlantic is anomalously warm (cold). Lastly, the magnitude of the SLPA patterns over the NAE sector appears poorly related to the intensity of sea-surface temperature anomalies in the central and eastern equatorial Pacific. Copyright © 2003 Royal Meteorological Society [source] Spring Cereals for Forage and Grain Production in a Cool Maritime ClimateJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2003A. G. Todd Abstract Newfoundland's climate is marginal for agricultural production. The availability of locally grown cereal grain and high-quality forage are major limitations to successful animal agriculture in this region. Here, our overall objective was to compare several spring cereal species for both annual forage and grain production in Newfoundland's cool Maritime climate. Several varieties of barley (Hordeum vulgare L.), wheat (Triticum aesitivum L.), oats (Avena sativa L.) and pea (Pisum sativum L.),cereal mixtures for forage yield and quality, as well as grain yield and maturity, were compared in field trials on the east and west coasts in both 1999 and 2000. Barley headed earliest, yielded greatest forage dry matter, had lowest forage protein and acid detergent fibre (ADF) percentages, and had neutral detergent fibre (NDF) mean values greater than those of pea,cereal mixtures, but less than those of oats and wheat. Forage harvested from pea,cereal mixtures was similar to that of barley for yield, ADF and NDF, while P and protein percentage were much greater. Barley matured 10,15 days earlier than both wheat and oats. In general terms, all three spring cereals exhibited similar grain yield potential. Oats tillered less, but compensated by producing more kernels spike,1. Days to maturity for cereal grains in western Newfoundland were roughly similar to those reported for the Maritime provinces of Canada. Yield and maturity results for both forage and grain production suggest that eastern Newfoundland is a unique agro-ecoregion in North America, and agronomic recommendations specific to other regions may not be applicable in this region. [source] Climatic limits for the present distribution of beech (Fagus L.) species in the worldJOURNAL OF BIOGEOGRAPHY, Issue 10 2006Jingyun Fang Abstract Aim, Beech (Fagus L., Fagaceae) species are representative trees of temperate deciduous broadleaf forests in the Northern Hemisphere. We focus on the distributional limits of beech species, in particular on identifying climatic factors associated with their present range limits. Location, Beech species occur in East Asia, Europe and West Asia, and North America. We collated information on both the southern and northern range limits and the lower and upper elevational limits for beech species in each region. Methods, In total, 292 lower/southern limit and 310 upper/northern limit sites with available climatic data for all 11 extant beech species were collected by reviewing the literature, and 13 climatic variables were estimated for each site from climate normals at nearby stations. We used principal components analysis (PCA) to detect climatic variables most strongly associated with the distribution of beech species and to compare the climatic spaces for the different beech species. Results, Statistics for thermal and moisture climatic conditions at the lower/southern and upper/northern limits of all world beech species are presented. The first two PCA components accounted for 70% and 68% of the overall variance in lower/southern and upper/northern range limits, respectively. The first PCA axis represented a thermal gradient, and the second a moisture gradient associated with the world-wide distribution pattern of beech species. Among thermal variables, growing season warmth was most important for beech distribution, but winter low temperature (coldness and mean temperature for the coldest month) and climatic continentality were also coupled with beech occurrence. The moisture gradient, indicated by precipitation and moisture indices, showed regional differences. American beech had the widest thermal range, Japanese beeches the most narrow; European beeches occurred in the driest climate, Japanese beeches the most humid. Climatic spaces for Chinese beech species were between those of American and European species. Main conclusions, The distributional limits of beech species were primarily associated with thermal factors, but moisture regime also played a role. There were some regional differences in the climatic correlates of distribution. The growing season temperature regime was most important in explaining distribution of Chinese beeches, whilst their northward distribution was mainly limited by shortage of precipitation. In Japan, distribution limits of beech species were correlated with summer temperature, but the local dominance of beech was likely to be dependent on snowfall and winter low temperature. High summer temperature was probably a limiting factor for southward extension of American beech, while growing season warmth seemed critical for its northward distribution. Although the present distribution of beech species corresponded well to the contemporary climate in most areas, climatic factors could not account for some distributions, e. g., that of F. mexicana compared to its close relative F. grandifolia. It is likely that historical factors play a secondary role in determining the present distribution of beech species. The lack of F. grandifolia on the island of Newfoundland, Canada, may be due to inadequate growing season warmth. Similarly, the northerly distribution of beech in Britain has not reached its potential limit, perhaps due to insufficient time since deglaciation to expand its range. [source] Genetic divergence between sympatric Arctic charr Salvelinus alpinus morphs in Gander Lake, Newfoundland: roles of migration, mutation and unequal effective population sizesJOURNAL OF FISH BIOLOGY, Issue 8 2008D. Gomez-Uchida A suite of 10 microsatellite loci was used to examine genetic divergence between two sympatric morphs of Arctic charr Salvelinus alpinus (,dark' and ,pale') inhabiting Gander Lake, Newfoundland. Results can be summarized as follows: (1) the morphs are strongly reproductively isolated , gene flow,migration estimates were consistently low in long and short-term evolutionary timescales of analysis; (2) intermorph divergence based on allele size (RST) was significantly larger than those based on allele state (,) implying a cumulative effect of stepwise-like mutations; (3) historical (coalescent) and current (linkage disequilibrium) point estimates of effective population size (Ne) were consistently higher for dark than for pale S. alpinus. The first and second findings lend support to the hypothesis that divergence between forms may have preceded the last glacial period (ending c. 12 000 years bp). The third finding argues for significant differences in habitat quantity and quality between morphs, which were emphasized in a previous study. Overall, these analyses underscore the importance of genetic assessment and monitoring in the conservation of fish diversity, with emphasis on ,rare' or under-represented forms among temperate species pairs. [source] Microgeographic population structure of brook charr: a comparison of microsatellite and mark-recapture dataJOURNAL OF FISH BIOLOGY, Issue 3 2003B. K. Adams Polymorphism at five microsatellite genetic markers (genotyped n = 496) and mark-recapture tagging data (tagged n = 9813) were used to define the population structure of brook charr, Salvelinus fontinalis from the Indian Bay watershed, Newfoundland, Canada. Despite the absence of physical barriers to migration among lakes, both genetic and tagging data suggest that brook charr in each lake represent reproductively isolated populations. Exact tests comparing allele frequencies, , (global value = 0·063), Rst (global value = 0·052), individual assignment tests, and Nei's genetic distance provided congruent estimates of population subdivision in agreement with the tagging data (only 2·2% of recaptures were lake-to-lake). The genetic structure of the brook charr populations corresponded with the geographic structure of the drainage basin on a qualitative level, although linear distance over water was not significantly correlated with the tagging data or the genetic distance measures. The agreement between the tagging and the genetic data suggest that microsatellite markers can be useful tools for defining real biological units. The results also suggest that brook charr exhibit microgeographic population structure at the watershed scale, and that this is the scale at which conservation and management of this salmonid might best be implemented. [source] Genetic analysis of aquabirnaviruses isolated from wild fish reveals occurrence of natural reassortment of infectious pancreatic necrosis virusJOURNAL OF FISH DISEASES, Issue 7 2009I Romero-Brey Abstract In this study, we report the sequencing of the whole genome [including the 5, and 3, non-coding regions (NCR) of both segments A and B] of seven birnavirus strains isolated from wild fish from the Flemish Cap (FC) fishery at Newfoundland, Canada. From analysis and comparison of the sequences, most of the FC isolates clustered with the North American reference strains West Buxton (WB), Dry Mill and Jasper. One strain was included in the same genotype as the European strain Ab. In addition, at least in one case cohabitation of both type strains in an individual fish was demonstrated. These results clearly suggest the acquisition of the viruses from two different sources. The prevalence of the American type is easily explained by the close proximity of this fishing bank to the American coast whereas, although surprising, the presence of the European type strain could be because of migration of fish from European waters. In one strain, segment A and B sequences were typed differently (WB and Ab, respectively). These findings indicate natural reassortment between two strains of aquabirnaviruses in a host. [source] Contesting meaning: Newfie and the politics of ethnic labellingJOURNAL OF SOCIOLINGUISTICS, Issue 4 2002Ruth King The ethnic label Newfie is a site of ideological dispute: for some, it is simply an informal term for residents and expatriates of the Canadian province of Newfoundland, for others it may function as an in,group term of solidarity which takes on negative connotations when used by non,Newfoundlanders, and for still others it is the equivalent of a racial slur. In this study we first trace the history of the term, a fairly recent innovation. We then examine present,day attitudes as expressed in (provincial and national) media discourse and in self,report data. We argue that debate over Newfie is part of a larger ideological struggle concerning the commodification of an ,invented' Newfoundland culture, which itself must be understood in terms of Newfoundland's socioeconomic position as Canada's poorest province. Finally, we compare the Newfie case to other instances of contested group labelling. [source] A scratch circle origin for the medusoid fossil KullingiaLETHAIA, Issue 4 2002SÖREN JENSEN Kullingia is considered a key taxon in demonstrating the presence of terminal Proterozoic-early Cambrian chondrophorine hydrozoans. However, Kullingia concentrica from the Lower Cambrian of northern Sweden possesses several features that show that it is not a body fossil but that it was formed by current or wave-induced rotation of an anchored tubular organism, possibly a sabelliditid. A scratch circle interpretation applies also to several other reports of Lower Cambrian Kullingia, including Kullingia delicata from the Chapel Island Formation of Newfoundland. Given the considerable number of problematic fossils that have been interpreted as chondrophorines, it is difficult to put an age on the oldest fossil chondrophorines, but it may be as late as the Devonian. Overall, scratch circles appear to be rarely preserved. The occurrence of these scratch circles in Lower Paleozoic storm deposits is probably related to low levels of bioturbation that enhanced both the likelihood of formation and preservation of these structures. [source] Palaeobiology and evolution of the earliest agglutinated Foraminifera: Platysolenites, Spirosolenites and related formsLETHAIA, Issue 1 2001Duncan McIlroy Tubular agglutinated fossils of Platysolenites antiquissimus Eichwald, 1860, P. cooperi n.sp. and Spirosolenites spiralis Glaessner, 1979 are examined from selected lower Cambrian successions in Avalonia (England; Wales; Newfoundland) and Baltica (Russia and Estonia). Platysolenites cooperi n.sp. is shown to extend below the first appearance of P. antiquissimus in the Neoproterozoic-Cambrian boundary stratotype region, SE Newfoundland, and to occur at higher stratigraphic levels in Wales and Finnmark. Taphonomic, teleological and ultrastructural studies on well-preserved material are consistent with a similar grade of organization and mode of life for P. antiquissimus and the living astrorhizacean foraminiferid Bathysiphon. However, agglutinated proloculi are here described from both rectilinear P. antiquissimus and coiled S. spiralis, which suggests that neither were typical astrorhizaceans. [source] Orographic influences during winter precipitation events on the Avalon Peninsula, NewfoundlandMETEOROLOGICAL APPLICATIONS, Issue 4 2000C E Banfield Precipitation enhancement over a low coastal hill in winter is demonstrated for particular associations of synoptically determined onshore airflow and local geography encountered over southeastern Newfoundland. Four such cases, involving a mixture of pre-warm-frontal precipitation types at surface temperatures just below freezing, are analysed using comparative surface gauge records from sites at the coast and hill summit and detailed volume scan data from a Doppler radar. Whilst precipitation at the hill summit and upwind coast was of similar overall duration in each case, the surface rates on the hilltop exceeded those at the coast by 1.0,4.0 mm h,1 during different stages of the events. Analysis of the Doppler reflectivity patterns reveals that intensities are especially enhanced near the windward hill crest, supporting the observed association of greatest enhancement with a strong local upslope wind component exceeding 20 m s,1. In the majority of these cases the enhancement is maintained primarily by the ,seeder,feeder' mechanism, which appears to be accelerated during precipitation transitions and with the surface warm front 120,150 km distant; however, a preliminary phase of enhancement due to topographically induced uplift of stable pre-frontal air is also recognised in one case. Copyright © 2000 Royal Meteorological Society [source] Interaction of landscape and life history attributes on genetic diversity, neutral divergence and gene flow in a pristine community of salmonidsMOLECULAR ECOLOGY, Issue 23 2009DANIEL GOMEZ-UCHIDA Abstract Landscape genetics holds promise for the forecasting of spatial patterns of genetic diversity based on key environmental features. Yet, the degree to which inferences based on single species can be extended to whole communities is not fully understood. We used a pristine and spatially structured community of three landlocked salmonids (Salvelinus fontinalis, Salmo salar, and Salvelinus alpinus) from Gros Morne National Park (Newfoundland, Canada) to test several predictions on the interacting effects of landscape and life history variation on genetic diversity, neutral divergence, and gene flow (m, migration rate). Landscape factors consistently influenced multispecies genetic patterns: (i) waterfalls created strong dichotomies in genetic diversity and divergence between populations above and below them in all three salmonids; (ii) contemporary m decreased with waterway distance in all three species, while neutral genetic divergence (,) increased with waterway distance, albeit in only two taxa; (iii) river flow generally produced downstream-biased m between populations when waterfalls separated these, but not otherwise. In contrast, we expected differential life history to result in a hierarchy of neutral divergence (S. salar > S. fontinalis > S. alpinus) based on disparities in dispersal abilities and population size from previous mark-recapture studies. Such hierarchy additionally matched varying degrees of spatial genetic structure among species revealed through individual-based analyses. We conclude that, whereas key landscape attributes hold power to predict multispecies genetic patterns in equivalent communities, they are likely to interact with species-specific life history attributes such as dispersal, demography, and ecology, which will in turn affect holistic conservation strategies. [source] Phylogeography and genetic structure of northern populations of the yellow warbler (Dendroica petechia)MOLECULAR ECOLOGY, Issue 6 2000Emmanuel Milot Abstract Phylogeographic patterns of intraspecific variation can provide insights into the population-level processes responsible for speciation and yield information useful for conservation purposes. To examine phylogeography and population structure in a migratory passerine bird at both continental and regional geographical scales, we analysed 344 bp of mitochondrial DNA (mtDNA) control region sequence from 155 yellow warblers (Dendroica petechia) collected from seven locations across Canada and from Alaska. There is a major subdivision between eastern (Manitoba to Newfoundland) and western (Alaska and British Columbia) populations which appears to have developed during the recent Pleistocene. Some localities within these two regions also differ significantly in their genetic composition, suggesting further subdivision on a regional geographical scale. Eastern and western birds form distinct phylogeographic entities and the clustering of all western haplotypes with two eastern haplotypes suggests that the western haplotypes may be derived from an eastern lineage. Analyses based on coalescent models support this explanation for the origin of western haplotypes. These results are consistent with important features of Mengel's model of warbler diversification. From a conservation perspective they also suggest that individual populations of migrant birds may form demographically isolated management units on a smaller scale than previously appreciated. [source] The Place of "Others" in Hunter-Gatherer IntensificationAMERICAN ANTHROPOLOGIST, Issue 2 2005DONALD H. HOLLY JR. Archaeologists are interested in understanding the conditions under which hunter-gatherer intensification occurs. Typically, most models assign primacy to population pressure or social relations and address intensification as it occurs among foragers inhabiting arid or temperate environments. In this article, I explore episodes of resource intensification and "deintensification" on the subarctic island of Newfoundland. Correlating periods of resource intensification and "deintensification" with changes in the social landscape, I argue that the presence or absence of "Others" played a significant role in informing hunter-gatherer subsistence strategies and settlement patterns. [source] NOx Emissions Reduction Through Water InjectionNAVAL ENGINEERS JOURNAL, Issue 3 2006Ernst Radloff Transport Canada is committed to protect the environment and to achieve a more sustainable transportation system. The Transportation Development Centre of Transport Canada, in collaboration with the Environment Research and Measurement Division of Environment Canada, is conducting research on marine emissions control technologies to lower greenhouse gas (GHG) emissions. » The ongoing work on emissions control technologies comprises both laboratory and field trials. An initial round of laboratory tests demonstrated the viability of a Water Injection System (WIS) to reduce NOx emissions. The results indicate that the WIS has achieved a 20 to 28% NOx reduction over a 25 to 75% load range with a maximum of 33% water injection. The WIS was optimized during laboratory bench tests and will be installed on a RORO vessel operating between Montreal, Quebec, and St. John's, Newfoundland. The WIS provides a cost-effective solution for NOx reduction on Canadian vessels fitted with older medium-speed engines. [source] Xiphograptus and the evolution of virgella-bearing graptoloidsPALAEONTOLOGY, Issue 2 2010JÖRG MALETZ Abstract:, The virgellar spine is one of the most consistent features of the graptolite sicula. It is present in a large number of graptoloid groups, but evolved separately and independently in these as it is seen from the presence of the spine in either ventral (Axonophora) or dorsal (Phyllograptus, Xiphograptus) position. The evolution of the virgellar spine in the Pan-Bireclinata in the Upper Dapingian to Lower Darriwilian time interval is known to follow four main steps, from a simple rutellum, through a lamelliform rutellum and a lanceolate virgella to the true virgellar spine. For the xiphograptids and in Phyllograptus, the origin and early development is less well documented, but appears to follow a similar path. However, the individual stages are condensed, and a true virgellar spine emerges already in the Floian time interval. A virgellar spine was found in Didymograptellus bifidus, necessitating a revision of the diagnosis of the genus Didymograptellus. A number of species of the virgellate genera Xiphograptus, Yutagraptus and Didymograptellus are described from isolated material for the first time. The species are useful for the biostratigraphic correlation of endemic mid-continent North American faunas with the Pacific Type faunal realm. Xiphograptus artus sp. nov., Didymograptellus primus sp. nov. and Didymograptellus cowheadensis sp. nov. from the Cow Head Group of western Newfoundland are described as new. [source] | ||||||||||||||||||||||||||||||||||