L'enneigement hivernal : un facteur de variation du recrutement chez l'isard (Rupicapra pyrenaica pyrenaica)

2002 ◽  
Vol 80 (7) ◽  
pp. 1306-1312 ◽  
Author(s):  
J -P Crampe ◽  
J -M Gaillard ◽  
A Loison
Keyword(s):  
Population Dynamics ◽  
Climatic Conditions ◽  
Snow Accumulation ◽  
Yearly Variation ◽  
Rupicapra Pyrenaica ◽  
Winter Snow ◽  
Population Recruitment ◽  
The Mean ◽  
Mountain Ungulates ◽  
The Impact

To assess the relationships between winter climatic conditions and population dynamics of mountain ungulates, we monitored over the long term an unhunted isard (Rupicapra pyrenaica pyrenaica) population living in the Pyrénées National Park. We used general linear modelling to assess (i) the influence of the observation date (between November and April) of the transect sampled and of the year on population recruitment (proportion of females 2 years of age and older with kids at heel) and (ii) the impact of snow accumulation during winter (cumulated snow fall from November to April) on kid mortality. As expected, the mean number of kids per female decreased over the observation period. The mean number of kids per female showed marked among-year differences in initial recruitment (measured on 31 October) as well as in kid mortality (measured as the decrease in recruitment between 31 October and 31 March). This model accounted for 80% of the variability observed in the field data. Among-year differences in snow accumulation accounted for most (86%) of the yearly variation observed in kid mortality. Our study demonstrates that winter snow may severely affect juvenile survival, and thereby population dynamics of mountain ungulates.

SIMULATION MODEL FOR THE POPULATION DYNAMICS OF THE CARROT WEEVIL, LISTRONOTUS OREGONENSIS (LECONTE) (COLEOPTERA: CURCULIONIDAE)

1991 ◽  
Vol 123 (1) ◽  
pp. 63-76 ◽  
Author(s):  
D.X. Zhao ◽  
G. Boivin ◽  
R.K. Stewart
Keyword(s):  
Population Dynamics ◽  
Simulation Model ◽  
Mortality Rates ◽  
Egg Parasitoid ◽  
Adult Density ◽  
Larval Population ◽  
Listronotus Oregonensis ◽  
The Mean ◽  
Carrot Weevil ◽  
The Impact

AbstractA simulation model was developed for the population dynamics of a carrot weevil, Listronotus oregonensis (LeConte), population on muck-grown carrots. The model includes mortality rates of eggs, larvae, and pupae for different sowing dates of carrots. It also incorporates the overwintered adult density, the temperature-dependent growth rates of the above-mentioned life stages, the age-, temperature-, and phenology-dependent oviposition rates, and the impact of an egg parasitoid, Anaphes sordidatus (Girault), on egg mortality rates. Model output was evaluated by comparing simulated results with observed results on the seasonal totals and time of population peaks of the egg and larval populations. The mean percentage differences between the simulated and observed seasonal egg totals were 3.1 ± 0.66 (SE) in 1987 and 1988, and 4.2 ± 0.05 in 1989. They were not statistically different. The mean percentage differences between the simulated and observed seasonal larval totals were 10 ± 3.33 in 1987 and 1988 and 29.8 ± 0.66 in 1989. Independent data sets (i.e. field data in 1989) showed a significant increase in the simulation error of the larval population. Sensitivity analysis indicated that A. sordidatus had a large influence on the population dynamics of L. oregonensis.

Investigating global changes in snow dynamics and the impact on water resources

2020 ◽  
Author(s):  
Adrià Fontrodona Bach ◽  
Joshua Larsen ◽  
Ross Woods ◽  
Bettina Schaefli ◽  
Ryan Teuling
Keyword(s):  
Water Resources ◽  
Hydrological Cycle ◽  
Snow Accumulation ◽  
Global Changes ◽  
Hydrological Models ◽  
Winter Snow ◽  
Long Term Trends ◽  
And Shifts ◽  
The Impact

<p>Snow is a key component of the hydrological cycle in many regions of the world, providing a natural storage of water by accumulating snow in winter and releasing it in spring. Many ecosystems, societies and economies rely on this mechanism as a water resource. There is strong evidence in the literature that global warming leads to decreasing snowfall and snow accumulation and shifts the onset of the melt season to earlier in the year. However, little is known about how rising temperatures affect snowmelt rates and timing, and how these can have an impact on water resources for instance by changing the time and magnitude of streamflow. Some studies predict slower snowmelt rates in a warmer world, due to the onset of melt being earlier when there is less energy available for melt, but there is not yet an observation-based study showing such trends. As a first step, here we present preliminary results of observed long term trends in snowmelt rates from different climates. We use a dataset that has already shown strong decreasing signals for winter snow accumulation. Here we also present potential avenues to investigate the sensitivity of snowpacks and snowmelt regimes in different climatic settings to further rising temperatures using modeled snow dynamics. A few possibilities on how to link the snowpack dynamics to impacts in water resources are also discussed, for instance by comparing modelled dynamics to hydrological models and observations.</p>

scholarly journals Recent Increases in Winter Snowfall Provide Resilience to Very Small Glaciers in the Julian Alps, Europe

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 263
Author(s):  
Renato R. Colucci ◽  
Manja Žebre ◽  
Csaba Zsolt Torma ◽  
Neil F. Glasser ◽  
Eleonora Maset ◽  
...  
Keyword(s):  
Mass Balance ◽  
Atlantic Multidecadal Oscillation ◽  
Snow Accumulation ◽  
Annual Precipitation ◽  
Mean Annual Precipitation ◽  
European Alps ◽  
Positive Feedbacks ◽  
Winter Snow ◽  
Geodetic Mass Balance ◽  
The Impact

Very small glaciers (<0.5 km2) account for more than 80% of the total number of glaciers and more than 15% of the total glacier area in the European Alps. This study seeks to better understand the impact of extreme snowfall events on the resilience of very small glaciers and ice patches in the southeastern European Alps, an area with the highest mean annual precipitation in the entire Alpine chain. Mean annual precipitation here is up to 3300 mm water equivalent, and the winter snow accumulation is approximately 6.80 m at 1800 m asl averaged over the period 1979–2018. As a consequence, very small glaciers and ice/firn patches are still present in this area at rather low altitudes (1830–2340 m). We performed repeated geodetic mass balance measurements on 14 ice bodies during the period 2006–2018 and the results show an increase greater than 10% increase in ice volume over this period. This is in accordance with several extreme winter snow accumulations in the 2000s, promoting a positive mass balance in the following years. The long-term evolution of these very small glaciers and ice bodies matches well with changes in mean temperature of the ablation season linked to variability of Atlantic Multidecadal Oscillation. Nevertheless, the recent behaviour of such residual ice masses in this area where orographic precipitation represents an important component of weather amplification is somehow different to most of the Alps. We analysed synoptic meteorological conditions leading to the exceptional snowy winters in the 2000s, which appear to be related to the influence and modification of atmospheric planetary waves and Arctic Amplification, with further positive feedbacks due to change in local sea surface temperature and its interactions with low level flows and the orography. Although further summer warming is expected in the next decades, we conclude that modification of storm tracks and more frequent occurrence of extreme snowfall events during winter are crucial in ensuring the resilience of small glacial remnants in maritime alpine sectors.

scholarly journals Impact of Climate Change on the Distribution of Four Closely Related Orchis (Orchidaceae) Species

Diversity ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 312
Author(s):  
Alexandra Evans ◽  
Sam Janssens ◽  
Hans Jacquemyn
Keyword(s):  
Climate Change ◽  
Population Dynamics ◽  
Abiotic Factors ◽  
Climatic Conditions ◽  
Distribution Area ◽  
Suitable Habitat ◽  
Orchid Species ◽  
Impact Of Climate Change ◽  
Population Demographic ◽  
The Impact

Long-term monitoring programs and population demographic models have shown that the population dynamics of orchids are to a large extent dependent on prevailing weather conditions, suggesting that the changes in climatic conditions can have far reaching effects on the population dynamics and hence the distribution of orchids. Although a better understanding of the effects of climate change on the distribution of plants has become increasingly important during the final years, only a few studies have investigated the effects of changing temperature and precipitation on the distribution of orchids. In this study, we investigated the impact of climate change on the distribution of four terrestrial orchid species (Orchis anthropophora, Orchis militaris, Orchis purpurea and Orchis simia). Using bioclimatic data for current and future climate scenarios, habitat suitability, range shifts and the impact of different abiotic factors on the range of each species were modelled using Maxent. The results revealed an increase in suitable habitat area for O. anthropophora, O. purpurea and O. simia under each RCP (Representative Concentration Pathway) scenario, while a decrease was observed for O. militaris. Furthermore, all four of the orchids showed a shift to higher latitudes under the three RCPs leading to a significant range extension under mild climate change. Under severe climate change, a significant decline in the distribution area at the warm edge of their distributions was observed. Overall, these results show that mild climate change may be beneficial for the studied orchid species and lead to range expansion. However, continued warming may yet prove detrimental, as all species also showed pronounced declines at lower latitudes when temperature increases were larger than 4 °C.

Seasonality in the reproductive activity of male chinchillas on a breeding farm in the climatic conditions of southern Poland

2017 ◽  
Vol 13 (4) ◽  
pp. 17-27
Author(s):  
Olga Szeleszczuk ◽  
Aleksandra Kowalczyk ◽  
Alicja Satoła
Keyword(s):  
Reproductive Potential ◽  
Reproductive Activity ◽  
Climatic Conditions ◽  
Low Fertility ◽  
The Mean ◽  
Foundation Stock ◽  
Modern Breeding ◽  
The Impact ◽  
Strict Selection ◽  
Selection Of

Farmed chinchillas continue to have very low fertility and prolificacy, although the reproductive potential of females is much higher and can be exploited. An increasing number of studies deal with the specific nature of reproduction in this species, with particular focus on female fertility. However, there is a lack of analyses and studies of males. Therefore, this study has attempted to determine the impact of the season of the year on the reproductive activity of male chinchillas and on the results of their use for breeding in the period from January 1991 to December 1996. The analysis was conducted on farmed animals on one of the largest farms in Poland. The farm was established in 1991 with an initial foundation stock of about 150 females and 25 males. Breeding was based on animals imported from a reputable farm in Germany, from which modern breeding technologies were adopted as well. Polygamous breeding with 6 females per male is used. Sexual activity was varied between years. Taking into account the entire foundation stock, an average of 8.15 litters and 14.77 pups were obtained per male per year. Analysis of five selected males revealed higher values: the mean number of litters ranged from 7.13 to 11.8 and the litter size ranged from 1.9 to 2.59. Thus, better utilization of males for breeding is possible on chinchilla farms. The system of keeping a male with many females at the same time enables strict selection of males.

The importance of temperature and lipid accumulation for initiation and duration of Calanus hyperboreus spawning

2020 ◽  
Vol 42 (2) ◽  
pp. 159-171
Author(s):  
Mads Schultz ◽  
Torkel Gissel Nielsen ◽  
Eva Friis Møller
Keyword(s):  
Population Dynamics ◽  
Lipid Metabolism ◽  
Lipid Content ◽  
Egg Production ◽  
Arctic Ecosystems ◽  
Calanus Hyperboreus ◽  
Higher Temperature ◽  
The Mean ◽  
Increasing Temperature ◽  
The Impact

Abstract Large, lipid-storing copepods play a central role in marine Arctic ecosystems. Knowledge of the mechanisms that control their oogenesis is important for understanding their phenology and population dynamics. We investigated the impact of female lipid content on the timing and cumulative egg production (EP) of Calanus hyperboreus at 0, 3 and 6°C. The lipid content of females in early autumn was a good predictor of their EP potential. However, we saw no indication of a threshold in lipid content for initiation of spawning. Higher temperature resulted in 17 and 24 days earlier spawning at 3 and 6°C compared with 0°C, and the mean spawning duration was 8 and 30 days shorter, respectively. This illustrates that temperature affects the phenology of C. hyperboreus. When EP began, lipid metabolism increased 2–4 times. The females allocated 1.3 μg lipid per egg independent of temperature. However, the basic metabolism increased with increasing temperature; consequently, a smaller fraction of lipid was allocated for EP when the temperature increased.

Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

1997 ◽  
Vol 161 ◽  
pp. 197-201 ◽  
Author(s):  
Duncan Steel
Keyword(s):  
Probability Distributions ◽  
Regions Of Interest ◽  
Significant Fraction ◽  
Organic Chemicals ◽  
Impact Speed ◽  
The Mean ◽  
The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

Sound Production Treatment for Acquired Apraxia of Speech: An Examination of Dosage in Relation to Probe Performance

2020 ◽  
pp. 1-16
Author(s):  
Julie L. Wambaugh ◽  
Lydia Kallhoff ◽  
Christina Nessler
Keyword(s):  
Retrospective Analysis ◽  
Sound Production ◽  
Apraxia Of Speech ◽  
Practice Schedule ◽  
Practice Schedules ◽  
Baseline Performance ◽  
The Mean ◽  
Number Of Treatment ◽  
The Impact

Purpose This study was designed to examine the association of dosage and effects of Sound Production Treatment (SPT) for acquired apraxia of speech. Method Treatment logs and probe data from 20 speakers with apraxia of speech and aphasia were submitted to a retrospective analysis. The number of treatment sessions and teaching episodes was examined relative to (a) change in articulation accuracy above baseline performance, (b) mastery of production, and (c) maintenance. The impact of practice schedule (SPT-Blocked vs. SPT-Random) was also examined. Results The average number of treatment sessions conducted prior to change was 5.4 for SPT-Blocked and 3.9 for SPT-Random. The mean number of teaching episodes preceding change was 334 for SPT-Blocked and 179 for SPT-Random. Mastery occurred within an average of 13.7 sessions (1,252 teaching episodes) and 12.4 sessions (1,082 teaching episodes) for SPT-Blocked and SPT-Random, respectively. Comparisons of dosage metric values across practice schedules did not reveal substantial differences. Significant negative correlations were found between follow-up probe performance and the dosage metrics. Conclusions Only a few treatment sessions were needed to achieve initial positive changes in articulation, with mastery occurring within 12–14 sessions for the majority of participants. Earlier occurrence of change or mastery was associated with better follow-up performance. Supplemental Material https://doi.org/10.23641/asha.12592190

Impact of roof shading on building energy performance in warm & humid climatic places of India

2020 ◽  
pp. 50-64
Author(s):  
Kuladeep Kumar Sadevi ◽  
Avlokita Agrawal
Keyword(s):  
Energy Consumption ◽  
Energy Conservation ◽  
Energy Performance ◽  
General Assumption ◽  
Climatic Conditions ◽  
Building Envelope ◽  
Passive Cooling ◽  
Base Case ◽  
U Value ◽  
The Impact

With the rise in awareness of energy efficient buildings and adoption of mandatory energy conservation codes across the globe, significant change is being observed in the way the buildings are designed. With the launch of Energy Conservation Building Code (ECBC) in India, climate responsive designs and passive cooling techniques are being explored increasingly in building designs. Of all the building envelope components, roof surface has been identified as the most significant with respect to the heat gain due to the incident solar radiation on buildings, especially in tropical climatic conditions. Since ECBC specifies stringent U-Values for roof assembly, use of insulating materials is becoming popular. Along with insulation, the shading of the roof is also observed to be an important strategy for improving thermal performance of the building, especially in Warm and humid climatic conditions. This study intends to assess the impact of roof shading on building’s energy performance in comparison to that of exposed roof with insulation. A typical office building with specific geometry and schedules has been identified as base case model for this study. This building is simulated using energy modelling software ‘Design Builder’ with base case parameters as prescribed in ECBC. Further, the same building has been simulated parametrically adjusting the amount of roof insulation and roof shading simultaneously. The overall energy consumption and the envelope performance of the top floor are extracted for analysis. The results indicate that the roof shading is an effective passive cooling strategy for both naturally ventilated and air conditioned buildings in Warm and humid climates of India. It is also observed that a fully shaded roof outperforms the insulated roof as per ECBC prescription. Provision of shading over roof reduces the annual energy consumption of building in case of both insulated and uninsulated roofs. However, the impact is higher for uninsulated roofs (U-Value of 3.933 W/m2K), being 4.18% as compared to 0.59% for insulated roofs (U-Value of 0.33 W/m2K).While the general assumption is that roof insulation helps in reducing the energy consumption in tropical buildings, it is observed to be the other way when insulation is provided with roof shading. It is due to restricted heat loss during night.

Long-term population dynamics of the red deer and European roe deer at the protected and not-protected areas in Mountain Crimea

2017 ◽  
Vol 7 (4) ◽  
pp. 65-72
Author(s):  
V. N. Shmagol' ◽  
V. L. Yarysh ◽  
S. P. Ivanov ◽  
V. I. Maltsev
Keyword(s):  
Population Dynamics ◽  
Protected Areas ◽  
Red Deer ◽  
Nature Reserve ◽  
Roe Deer ◽  
Precipitation Amount ◽  
Annual Precipitation ◽  
Population Number ◽  
The Impact

<p>The long-term population dynamics of the red deer (<em>Cervus elaphus</em> L.) and European roe deer (<em>Capreolus</em> <em>capreolus</em> L.) at the mountain and forest zone of Crimea during 1980-2017 is presented. Fluctuations in numbers of both species are cyclical and partly synchronous. Period of oscillations in the population of red deer is about 25 years, the average duration of the oscillation period of number of roe deer is 12.3 years. During the fluctuations in the number the increasing and fall in population number of the red deer had been as 26-47 %, and roe deer – as 22-34 %. Basing on the dada obtained we have assumed that together with large-scale cycles of fluctuations in population number of both red deer and roe deer the short cycles of fluctuations in the number of these species with period from 3.5 to 7.5 years take place. Significant differences of the parameters of cyclical fluctuations in the number of roe deer at some sites of the Mountainous Crimea: breaches of synchronicity, as well as significant differences in the duration of cycles are revealed. The greatest deviations from the average values of parameters of long-term dynamics of the number of roe deer in Crimea are noted for groups of this species at two protected areas. At the Crimean Nature Reserve the cycle time of fluctuations of the numbers of roe deer was 18 years. At the Karadag Nature Reserve since 1976 we can see an exponential growth in number of roe deer that is continued up to the present time. By 2016 the number of roe deer reached 750 individuals at a density of 437 animals per 1 thousand ha. Peculiarity of dynamics of number of roe deer at some sites proves the existence in the mountain forest of Crimea several relatively isolated groups of deer. We assumed that "island" location of the Crimean populations of red deer and European roe deer, their relatively little number and influence of permanent extreme factors of both natural and anthropogenic origination have contributed to a mechanism of survival of these populations. The elements of such a mechanism include the following features of long-term dynamics of the population: the reduction in the period of cyclic population fluctuations, while maintaining their amplitude and the appearance of additional small cycles, providing more flexible response of the population to the impact of both negative and positive environmental factors. From the totality of the weather conditions for the Crimean population of roe deer the recurring periods of increases and downs in the annual precipitation amount may have relevance. There was a trend of increase in the roe deer population during periods of increasing annual precipitation.</p>

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