Climate change and abundance cycles of two sympatric populations of smelt (Osmerus mordax) in the middle estuary of the St. Lawrence River, Canada

2001 ◽  
Vol 58 (10) ◽  
pp. 2048-2058 ◽  
Author(s):  
M Mingelbier ◽  
F Lecomte ◽  
J J Dodson
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Climatic Factors ◽  
Future Climate Change ◽  
Osmerus Mordax ◽  
Sympatric Populations ◽  
North Shore ◽  
South Shore ◽  
Middle Estuary ◽  
St Lawrence River

Commercial catches of two ecologically distinct sympatric smelt (Osmerus mordax) populations segregated along the two shores of the St. Lawrence middle estuary exhibited inverse patterns with periodicities on the order of 30 years. The influence of water level in the St. Lawrence River and air temperature, chosen to reflect variations in hydrology and climate, differed markedly between the two populations. Analyses revealed that both water level and temperature were generally positively related with north-shore smelt landings and negatively related with south-shore smelt landings. For both populations, a number of significant climatic factors contributing to variance in smelt landings were lagged by one to three years relative to the year of landings, indicating that climatic variables influenced smelt recruitment. The contrasting role of hydroclimatic variables in driving these abundance cycles is likely related to differential exploitation of estuarine habitats; the south-shore population is associated with shallow shoal habitat, whereas the north-shore population is associated with deep channel habitat. The responses of the two smelt populations also reflect the fundamental ecological differences existing between shoal and channel habitats, indicating that future climate change may differentially affect other populations or species that are segregated between these two habitats.

A mtDNA analysis of spatiotemporal distribution of two sympatric larval populations of rainbow smelt (Osmerus mordax) in the St. Lawrence River estuary, Quebec, Canada

1998 ◽  
Vol 55 (7) ◽  
pp. 1739-1747 ◽  
Author(s):  
Dany Pigeon ◽  
Julian J Dodson ◽  
Louis Bernatchez
Keyword(s):  
Resource Partitioning ◽  
River Estuary ◽  
Osmerus Mordax ◽  
Relative Distribution ◽  
Sympatric Populations ◽  
Rainbow Smelt ◽  
Genetic Population ◽  
Spatial Homogeneity ◽  
Middle Estuary ◽  
St Lawrence River

Ecological isolation through resource partitioning is invoked as a major factor for explaining the persistence of genetically distinct yet closely related sympatric populations. Two genetically distinct sympatric populations of anadromous rainbow smelt (Osmerus mordax) exist in the middle estuary of the St. Lawrence River. The persistence of these coexisting populations in sympatry is in conflict with current theoretical concepts predicting population richness. In the present study, we performed mtDNA PCR-RFLP analysis of 922 larvae from 33 sampling stations to test the hypothesis that the larvae belonging to the two sympatric smelt populations of the St. Lawrence middle estuary are spatially segregated and that such segregation may promote the persistence of the populations. Results clearly revealed spatial homogeneity in the relative distribution of larvae from the two populations. Consequently, they did not support our working hypothesis that larvae belonging to the two sympatric smelt populations are spatially segregated. Two alternative explanations may account for the lack of spatial partitioning observed here. Competition may not be important enough to promote resource partitioning at the larval stage. Alternatively, resource partitioning occurs, but not spatially. This study also demonstrated that the effect of historical events may have been as important as contemporary ecological settings in determining genetic population structure in smelt.

Dispersion and Retention of Anadromous Rainbow Smelt (Osmerus mordax) Larvae in the Middle Estuary of the St. Lawrence River

1985 ◽  
Vol 42 (2) ◽  
pp. 332-341 ◽  
Author(s):  
Patrick Quellet ◽  
Julian J. Dodson
Keyword(s):  
Water Mass ◽  
High Tide ◽  
Horizontal Distribution ◽  
Circulation System ◽  
Larval Abundance ◽  
Osmerus Mordax ◽  
Rainbow Smelt ◽  
Lawrence Estuary ◽  
Middle Estuary ◽  
St Lawrence River

The vertical and horizontal distribution of anadromous rainbow smelt (Osmerus mordax) larvae from hatching in their natal river to their occupation of nursery areas in the middle estuary of the St. Lawrence River was documented to describe the mechanism responsible for the retention of smelt larvae in this area. Peaks of larval abundance observed downstream of the spawning grounds indicate a 24-h periodicity in hatching and the introduction of larvae into the riverine circulation. No retention of larvae was observed between the spawning ground and the downstream portion of the natal river. Our evidence indicates daytime accumulation of larvae at the mouth of the natal river, possibly resulting from the negative phototaxis exhibited by small smelt larvae. Patches of smelt larvae were incorporated into the St. Lawrence estuarine water mass once every 24 h at night following high tide. The subsequent downstream transport of larvae in the St. Lawrence estuary appears slower than the advection of the water mass due to the tendency of larvae to remain deeper in the water column during ebb tides and to concentrate near the surface during flood tides. Smelt larvae are transported from the south shore to the partially mixed northern portion of the middle estuary which represents the principal zone of larval smelt accumulation. We propose that the vertical displacements exhibited by smelt larvae in combination with the two-layer circulation system of the northern middle estuary results in the retention of smelt larvae in this region.

Preliminary interpretation of the first refraction arrivals in Gaspé from shots in Labrador and Quebec

1969 ◽  
Vol 6 (4) ◽  
pp. 771-774 ◽  
Author(s):  
Douglas S. Rankin ◽  
Ravi Ravindra ◽  
David Zwicker
Keyword(s):  
Upper Mantle ◽  
Arrival Time ◽  
The South ◽  
North Shore ◽  
The North ◽  
A Value ◽  
South Shore ◽  
Compressional Velocity ◽  
St Lawrence River

Previous work in the Gulf of St. Lawrence has yielded an unusually high upper-mantle compressional velocity. In the Gaspé area a more recent determination has yielded a value of 8.75 ± 0.20 km/s for an unreversed profile. The arrival time at a station on the north shore of the St. Lawrence River suggests that there is no major difference in velocity and depth relative to the south shore.

scholarly journals Spatial and Temporal Variations of Potential Evapotranspiration in the Loess Plateau of China During 1960–2017

2020 ◽  
Vol 12 (1) ◽  
pp. 354 ◽  
Author(s):  
Congjian Sun ◽  
Zhenjing Zheng ◽  
Wei Chen ◽  
Yuyang Wang
Keyword(s):  
Climate Change ◽  
Loess Plateau ◽  
Hydrological Cycle ◽  
Climatic Factors ◽  
Potential Evapotranspiration ◽  
Southern Oscillation ◽  
Chinese Loess Plateau ◽  
Future Climate Change ◽  
Strong Positive Correlation ◽  
The Loess Plateau

Potential evapotranspiration (ET0) is an integral component of the hydrological cycle and the global energy balance, and its long-term variation is of much concern in climate change studies. The Loess Plateau is an important area of agricultural civilization and water resources research. This study analyzed the spatial and temporal evolution processes and influential parameters of ET0 at 70 stations in different topographical areas of the Chinese Loess Plateau (CLP). Using the Mann–Kendall trend, Cross wavelet transform, and the ArcGIS platform, the ET0 of each station was quantified using the Penman–Monteith equation, and the effects of climatic factors on ET0 were assessed by analyzing the correlation coefficients and contribution rates of the climatic factors. The results showed that: (1) the overall trend of the ET0 in different terrains of the Loess Plateau is consistent, however, the ET0 values differ; the hill region (HR) has the highest ET0, followed by the valley region (VR), and the mountain region (MR) has the lowest, and ET0 changes differ between seasons. (2) Spatial distribution characteristics of multiyear mean ET0 in the study are as follows: the ET0 values in mountain and hilly areas are decreasing from west to east, and the higher mean annual ET0 value in the VR is mainly concentrated in the eastern CLP. (3) In the past 58 years, the annual mean and the seasonal ET0 of the region showed increasing trends, however, differences in different terrains were obvious. (4) ET0 has significant correlations with El Niño–Southern Oscillation (ENSO), Pacific–North American teleconnection (PNA), and Atlantic Multidecadal Oscillation (AMO). The resonance period of ET0 and ENSO was 3–6 a, mainly in 1976–1985. The mean coherence phase angle was close to 360°, indicating that ET0 lags behind PNA by approximately 2–6 a; ET0 has a very strong positive correlation with AMO. (5) Relative humidity (RH) is the main influencing factor of ET0 change in the Loess Plateau. Temperature (T) variation has the highest contribution rate (42%) to the regional ET0 variation in the entire CLP. We should pay more attention to the variation of evaporation under future climate change, especially temperature change.

Climatic factors influencing New Zealand pasture resilience under scenarios of future climate change

2021 ◽  
Vol 17 ◽  
Author(s):  
Elizabeth Keller ◽  
Mark Lieffering ◽  
Jing Guo ◽  
W Troy Baisden ◽  
Anne-Gaelle Ausseil
Keyword(s):  
Climate Change ◽  
New Zealand ◽  
Climatic Factors ◽  
Early Spring ◽  
Future Climate ◽  
Future Climate Change ◽  
Fertilization Effect ◽  
Intensively Managed ◽  
Growing Conditions ◽  
Grazing Livestock

New Zealand’s intensively managed pastoral agricultural systems are vulnerable to climate change because of their dependence on grazing livestock and pasture as the primary feed supply. Drawing from recent modelling results, annual pasture yields in New Zealand are projected to be robust to a changing climate due to more favourable growing conditions in winter and early spring and increased plant efficiencies from the CO2 fertilization effect. However, growth is also expected to become more variable and unpredictable, particularly in water-limited regions. A combination of short-term, incremental changes (already part of current practice) and longer-term strategic interventions will be necessary to maintain consistent feed supply under future climate change.

Developing future sea level services for Small Island Developing States

2020 ◽  
Author(s):  
Svetlana Jevrejeva ◽  
Judith Wolf ◽  
Andy Matthews ◽  
Joanne Williams ◽  
David Byrne ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Water Level ◽  
Sea Level ◽  
Future Climate Change ◽  
Small Island ◽  
Caribbean Region ◽  
Caribbean Islands ◽  
The Caribbean ◽  
And Sea Level

<p>The Caribbean islands encompass some of the most vulnerable coastlines in terms of sea level rise, exposure to tropical cyclones, changes in waves and storm surges. Climate in the Caribbean is already changing and sea level rise impacts are already being felt. Considerable local and regional variations in the rate, magnitude, and direction of sea-level change can be expected as a result of thermal expansion, tectonic movements, and changes in ocean circulation. Governments in the Caribbean recognise that climate change and sea level rise are serious threats to the sustainable development and economic growth of the Caribbean islands and urgent actions are required to increase the resilience and make decisions about how to adapt to future climate change (Caribbean Marine Climate Change Report Card 2017; IPCC 2014).</p><p>As part of the UK Commonwealth Marine Economies (CME) Programme and through collaboration with local stakeholders in St Vincent, we have identified particular areas at risk from changing water level and wave conditions. The Caribbean Sea, particularly the Lesser Antilles, suffers from limited observational data due to a lack of coastal monitoring, making numerical models even more important to fill this gap. The current projects brings together improved access to tide gauge observations, as well as global, regional and local water level and wave modelling to provide useful tools for coastal planners.</p><p>We present our initial design of a coastal data hub with sea level information for stakeholder access in St. Vincent and Grenadines, Grenada and St Lucia, with potential development of the hub for the Caribbean region. The work presented here is a contribution to the wide range of ongoing activities under the Commonwealth Marine Economies (CME) Programme in the Caribbean, falling within the work package “Development of a coastal data hub for stakeholder access in the Caribbean region”, under the NOC led projects “Climate Change Impact Assessment: Ocean Modelling and Monitoring for the Caribbean CME states”.</p>

Methods and uncertainties in bioclimatic envelope modelling under climate change

2006 ◽  
Vol 30 (6) ◽  
pp. 751-777 ◽  
Author(s):  
Risto K. Heikkinen ◽  
Miska Luoto ◽  
Miguel B. Araújo ◽  
Raimo Virkkala ◽  
Wilfried Thuiller ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Climatic Factors ◽  
Future Climate Change ◽  
Future Research ◽  
Climate Change Scenarios ◽  
Distribution Models ◽  
Wide Range ◽  
Bioclimatic Modelling ◽  
Bioclimatic Envelope

Potential impacts of projected climate change on biodiversity are often assessed using single-species bioclimatic ‘envelope’models. Such models are a special case of species distribution models in which the current geographical distribution of species is related to climatic variables so to enable projections of distributions under future climate change scenarios. This work reviews a number of critical methodological issues that may lead to uncertainty in predictions from bioclimatic modelling. Particular attention is paid to recent developments of bioclimatic modelling that address some of these issues as well as to the topics where more progress needs to be made. Developing and applying bioclimatic models in a informative way requires good understanding of a wide range of methodologies, including the choice of modelling technique, model validation, collinearity, autocorrelation, biased sampling of explanatory variables, scaling and impacts of non-climatic factors. A key challenge for future research is integrating factors such as land cover, direct CO2 effects, biotic interactions and dispersal mechanisms into species-climate models. We conclude that, although bioclimatic envelope models have a number of important advantages, they need to be applied only when users of models have a thorough understanding of their limitations and uncertainties.

scholarly journals Contrasting multitaxon responses to climate change in Mediterranean mountains

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Luca Di Nuzzo ◽  
Chiara Vallese ◽  
Renato Benesperi ◽  
Paolo Giordani ◽  
Alessandro Chiarucci ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Richness ◽  
Functional Traits ◽  
Beta Diversity ◽  
Vascular Plants ◽  
Climatic Factors ◽  
Species Traits ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Diversity Patterns

AbstractWe explored the influence of climatic factors on diversity patterns of multiple taxa (lichens, bryophytes, and vascular plants) along a steep elevational gradient to predict communities’ dynamics under future climate change scenarios in Mediterranean regions. We analysed (1) species richness patterns in terms of heat-adapted, intermediate, and cold-adapted species; (2) pairwise beta-diversity patterns, also accounting for its two different components, species replacement and richness difference; (3) the influence of climatic variables on species functional traits. Species richness is influenced by different factors between three taxonomic groups, while beta diversity differs mainly between plants and cryptogams. Functional traits are influenced by different factors in each taxonomic group. On the basis of our observations, poikilohydric cryptogams could be more impacted by climate change than vascular plants. However, contrasting species-climate and traits-climate relationships were also found between lichens and bryophytes suggesting that each group may be sensitive to different components of climate change. Our study supports the usefulness of a multi-taxon approach coupled with a species traits analysis to better unravel the response of terrestrial communities to climate change. This would be especially relevant for lichens and bryophytes, whose response to climate change is still poorly explored.

scholarly journals Impact of climate change on potential distribution of xero-epiphytic selaginellas (Selaginella involvens and S. repanda) in Southeast Asia

2017 ◽  
Vol 18 (4) ◽  
pp. 1680-1695
Author(s):  
AHMAD DWI SETYAWAN ◽  
JATNA SUPRIATNA ◽  
DEDY DARNAEDI ◽  
ROKHMATULOH ROKHMATULOH ◽  
SUTARNO SUTARNO ◽  
...  
Keyword(s):  
Climate Change ◽  
Southeast Asia ◽  
Potential Distribution ◽  
Climatic Factors ◽  
Future Climate ◽  
Future Climate Change ◽  
Water Medium ◽  
Lower Altitude ◽  
Impact Of Climate Change ◽  
The Impact

Setyawan AD, Supriatna J, Darnaedi D, Rokhmatuloh, Sutarno, Sugiyarto, Nursamsi I, Komala WR, Pradan P. 2017. Impact of climate change on potential distribution of xero-epiphytic selaginellas (Selaginella involvens and S. repanda) in Southeast Asia. Biodiversitas 18: 1680-1695. Climate change is one of the greatest challenges for all life on earth, as it may become the dominant driver of changes in ecosystem services and biodiversity loss at the global level. Selaginella is a group of spike-mosses that seem easily affected by global warming (climate change) due to requiring water medium for fertilization. However, some species have been adapted to dry condition and may grow as epiphytes, such as S. involvens and S. repanda. Both species are commonly found in opposing a range of elevation. S. involvens is often found in high-altitude regions, whereas S. repanda is often found at lower-altitude regions. The difference in this altitudinal distributions is expected to limit redistribution mechanism of each species to adapt the climate change projections. This study model examines the potential geographic distribution of S. involvens and S. repanda under current climatic conditions and models the impact of projected climate change on their potential distribution. Future climate predictions are made with four detailed bioclimatic scenarios (i.e. RCP 2.6, RCP 4.5, RCP 6.0, and RCP 8.5) and three-time intervals (2030, 2050, 2080), which combine various climatic factors. In this modeling, it can be concluded that S. involvens and S. repanda can adapt to future climate change, and continue to be sustainable, although it is strongly influenced and shifting habitat distribution in some areas.

scholarly journals Integrated model projections of climate change impacts on water-level dynamics in the large Poyang Lake (China)

2019 ◽  
Author(s):  
Yunliang Li ◽  
Qi Zhang ◽  
Hui Tao ◽  
Jing Yao
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Lake Water ◽  
Hydrological Model ◽  
Poyang Lake ◽  
Baseline Period ◽  
Global Climate Models ◽  
Water Levels ◽  
Future Climate Change ◽  
Increased Risk

Abstract This study outlines a framework for examining potential impacts of future climate change in Poyang Lake water levels using linked models. The catchment hydrological model (WATLAC) was used to simulate river runoffs from a baseline period (1986–2005) and near-future (2020–2035) climate scenarios based on eight global climate models (GCMs). Outputs from the hydrological model combined with the Yangtze River's effects were fed into a lake water-level model, developing in the back-propagation neural network. Model projections indicate that spring–summer water levels of Poyang Lake are expected to increase by 5–25%, and autumn–winter water levels are likely to be lower and decrease by 5–30%, relative to the baseline period. This amounts to higher lake water levels by as much as 2 m in flood seasons and lower water levels in dry seasons in the range of 0.1–1.3 m, indicating that the lake may be wet-get-wetter and dry-get-drier. The probability of occurrence for both the extreme high and low water levels may exhibit obviously increasing trends by up to 5% more than at present, indicating an increased risk in the severity of lake floods and droughts. Projected changes also include possible shifts in the timing and magnitude of the lake water levels.

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