First estimates of the probability of survival in a small-bodied, high-elevation frog (Boreal Chorus Frog, Pseudacris maculata), or how historical data can be useful

2016 ◽  
Vol 94 (9) ◽  
pp. 599-606 ◽  
Author(s):  
E. Muths ◽  
R.D. Scherer ◽  
S.M. Amburgey ◽  
T. Matthews ◽  
A.W. Spencer ◽  
...  
Keyword(s):  
Historical Data ◽  
A Priori ◽  
Common Species ◽  
High Elevation ◽  
Color Morph ◽  
Historical Information ◽  
Probability Of Survival ◽  
Pseudacris Maculata ◽  
Recent Climate ◽  
Chorus Frog

In an era of shrinking budgets yet increasing demands for conservation, the value of existing (i.e., historical) data are elevated. Lengthy time series on common, or previously common, species are particularly valuable and may be available only through the use of historical information. We provide first estimates of the probability of survival and longevity (0.67–0.79 and 5–7 years, respectively) for a subalpine population of a small-bodied, ostensibly common amphibian, the Boreal Chorus Frog (Pseudacris maculata (Agassiz, 1850)), using historical data and contemporary, hypothesis-driven information–theoretic analyses. We also test a priori hypotheses about the effects of color morph (as suggested by early reports) and of drought (as suggested by recent climate predictions) on survival. Using robust mark–recapture models, we find some support for early hypotheses regarding the effect of color on survival, but we find no effect of drought. The congruence between early findings and our analyses highlights the usefulness of historical information in providing raw data for contemporary analyses and context for conservation and management decisions.

Efficient Reliability Assessment With the Conditional Probability Method

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Rami Mansour ◽  
Mårten Olsson
Keyword(s):  
Conditional Probability ◽  
Structural Reliability ◽  
A Priori ◽  
Reliability Assessment ◽  
Probability Of Failure ◽  
Assessment Method ◽  
Probability Method ◽  
Probability Of Survival ◽  
Design Variables ◽  
Reliability Method

Reliability assessment is an important procedure in engineering design in which the probability of failure or equivalently the probability of survival is computed based on appropriate design criteria and model behavior. In this paper, a new approximate and efficient reliability assessment method is proposed: the conditional probability method (CPM). Focus is set on computational efficiency and the proposed method is applied to classical load-strength structural reliability problems. The core of the approach is in the computation of the probability of failure starting from the conditional probability of failure given the load. The number of function evaluations to compute the probability of failure is a priori known to be 3n + 2 in CPM, where n is the number of stochastic design variables excluding the strength. The necessary number of function evaluations for the reliability assessment, which may correspond to expensive computations, is therefore substantially lower in CPM than in the existing structural reliability methods such as the widely used first-order reliability method (FORM).

Spatial patterns of high-elevation precipitation observed through spaceborne precipitation radars

2021 ◽  
Author(s):  
Masafumi Hirose ◽  
Hatsuki Fujinami
Keyword(s):  
A Priori ◽  
High Elevation ◽  
Occurrence Frequency ◽  
In Situ Observation ◽  
Dual Frequency ◽  
High Altitudes ◽  
Precipitation Radar ◽  
Glacier Terminus ◽  
Profile Correction ◽  
Trmm Pr

<p>Spaceborne-radar precipitation products at high altitudes entail close attention to geographically inherent retrieval uncertainties. The lowest levels free from surface clutter are ~1 km higher in rugged mountainous areas than those over flatlands. The clutter-removal filter masks precipitation echoes at altitudes below 3 km from the surface at the swath edge over narrow valleys in the Himalayas. In this study, precipitation profiles at levels with clutter interference were estimated using an a priori precipitation profile dataset based on near-nadir observations. The corrected precipitation dataset was generated based on the Tropical Rainfall Measuring Mission Precipitation Radar (TRMM PR) product at a spatial resolution of 0.01° around the Trambau Glacier terminus in the Nepal Himalayas, where ground observation sites were installed in 2016. The occurrence frequency of precipitation was considerably small compared with the in situ observation because of limitations in the sensor sensitivity. The occurrence frequency of light precipitation is increased by the Dual-frequency Precipitation Radar (DPR) onboard the Global Precipitation Measurement (GPM) Core Observatory, and the low-level precipitation profile correction mitigates underestimation bias by ~10%. In this presentation, the detectability of fine-scale precipitation climatology and the local characteristics of its diurnal variation at high altitudes are discussed based the combination of the TRMM PR and GPM DPR products.</p>

scholarly journals Has the Western Chorus Frog (Pseudacris triseriata) Declined in Western Ottawa, Ontario?

2011 ◽  
Vol 125 (3) ◽  
pp. 220
Author(s):  
David C. Seburn ◽  
Kari Gunson
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Historical Data ◽  
Current Status ◽  
Historical Records ◽  
Breeding Sites ◽  
Median Distance ◽  
Chorus Frogs ◽  
Historical Sites ◽  
Chorus Frog

To determine whether the Western Chorus Frog has declined in western Ottawa, we conducted auditory surveys at historical locations as well as at various other wetlands. Western Chorus Frogs were detected at 12 of 18 historical locations. Wetland habitat remained at all historical locations where the species was not detected. There was no difference in the year of historical records for sites where Western Chorus Frogs were (median 1987.5) and were not (median 1987.5) detected. In the present study, Western Chorus Frogs were also detected at 30 locations where they had not been previously reported. Historical sites where Western Chorus Frogs were not detected were not significantly farther away from known Western Chorus Frog sites (median distance: 2.2 km) than historical sites where Western Chorus Frogs were detected (median distance: 1.4 km). Land use variables for historical sites where Western Chorus Frogs were and were not detected did not vary significantly at any spatial scale from 0.5 to 2.0 km. Western Chorus Frogs were detected in areas with up to 50% forest cover and up to 86% agricultural cover at the 1.0-km radius. The lack of historical data makes it difficult to assess the current status of the Western Chorus Frog in western Ottawa. The species may have declined, remained approximately the same (by shifting to different breeding sites), or even increased its distribution (by colonizing additional sites).

scholarly journals Range dynamics of mountain plants decrease with elevation

2018 ◽  
Vol 115 (8) ◽  
pp. 1848-1853 ◽  
Author(s):  
Sabine B. Rumpf ◽  
Karl Hülber ◽  
Günther Klonner ◽  
Dietmar Moser ◽  
Martin Schütz ◽  
...  
Keyword(s):  
Plant Species ◽  
Species Abundance ◽  
Elevational Gradient ◽  
High Elevation ◽  
Range Limits ◽  
European Alps ◽  
Cold Adapted ◽  
Recent Climate ◽  
Range Dynamics ◽  
Mountain Plant

Many studies report that mountain plant species are shifting upward in elevation. However, the majority of these reports focus on shifts of upper limits. Here, we expand the focus and simultaneously analyze changes of both range limits, optima, and abundances of 183 mountain plant species. We therefore resurveyed 1,576 vegetation plots first recorded before 1970 in the European Alps. We found that both range limits and optima shifted upward in elevation, but the most pronounced trend was a mean increase in species abundance. Despite huge species-specific variation, range dynamics showed a consistent trend along the elevational gradient: Both range limits and optima shifted upslope faster the lower they were situated historically, and species’ abundance increased more for species from lower elevations. Traits affecting the species’ dispersal and persistence capacity were not related to their range dynamics. Using indicator values to stratify species by their thermal and nutrient demands revealed that elevational ranges of thermophilic species tended to expand, while those of cold-adapted species tended to contract. Abundance increases were strongest for nutriphilous species. These results suggest that recent climate warming interacted with airborne nitrogen deposition in driving the observed dynamics. So far, the majority of species appear as “winners” of recent changes, yet “losers” are overrepresented among high-elevation, cold-adapted species with low nutrient demands. In the decades to come, high-alpine species may hence face the double pressure of climatic changes and novel, superior competitors that move up faster than they themselves can escape to even higher elevations.

scholarly journals Mortality Forecasting: How Far Back Should We Look in Time?

Risks ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 22 ◽  
Author(s):  
Han Li ◽  
Colin O’Hare
Keyword(s):  
Predictive Power ◽  
Historical Data ◽  
Mortality Rates ◽  
Point Of View ◽  
Mortality Data ◽  
Male Mortality ◽  
Historical Information ◽  
Mortality Forecasting ◽  
Mortality Models ◽  
Forecasting Performance

Extrapolative methods are one of the most commonly-adopted forecasting approaches in the literature on projecting future mortality rates. It can be argued that there are two types of mortality models using this approach. The first extracts patterns in age, time and cohort dimensions either in a deterministic fashion or a stochastic fashion. The second uses non-parametric smoothing techniques to model mortality and thus has no explicit constraints placed on the model. We argue that from a forecasting point of view, the main difference between the two types of models is whether they treat recent and historical information equally in the projection process. In this paper, we compare the forecasting performance of the two types of models using Great Britain male mortality data from 1950–2016. We also conduct a robustness test to see how sensitive the forecasts are to the changes in the length of historical data used to calibrate the models. The main conclusion from the study is that more recent information should be given more weight in the forecasting process as it has greater predictive power over historical information.

scholarly journals Weak precipitation, warm winters and springs impact glaciers of south slopes of Mt. Everest (central Himalaya) in the last 2 decades (1994–2013)

2015 ◽  
Vol 9 (3) ◽  
pp. 1229-1247 ◽  
Author(s):  
F. Salerno ◽  
N. Guyennon ◽  
S. Thakuri ◽  
G. Viviano ◽  
E. Romano ◽  
...  
Keyword(s):  
Time Series ◽  
Monsoon Season ◽  
High Elevation ◽  
Maximum Temperature ◽  
Mountain Range ◽  
Climate Trends ◽  
Monsoon Period ◽  
Temperature And Precipitation ◽  
Recent Climate ◽  
Koshi Basin

Abstract. Studies on recent climate trends from the Himalayan range are limited, and even completely absent at high elevation (> 5000 m a.s.l.). This study specifically explores the southern slopes of Mt. Everest, analyzing the time series of temperature and precipitation reconstructed from seven stations located between 2660 and 5600 m a.s.l. during 1994–2013, complemented with the data from all existing ground weather stations located on both sides of the mountain range (Koshi Basin) over the same period. Overall we find that the main and most significant increase in temperature is concentrated outside of the monsoon period. Above 5000 m a.s.l. the increasing trend in the time series of minimum temperature (+0.072 °C yr−1) is much stronger than of maximum temperature (+0.009 °C yr−1), while the mean temperature increased by +0.044 °C yr−1. Moreover, we note a substantial liquid precipitation weakening (−9.3 mm yr−1) during the monsoon season. The annual rate of decrease in precipitation at higher elevations is similar to the one at lower elevations on the southern side of the Koshi Basin, but the drier conditions of this remote environment make the fractional loss much more consistent (−47% during the monsoon period). Our results challenge the assumptions on whether temperature or precipitation is the main driver of recent glacier mass changes in the region. The main implications are the following: (1) the negative mass balances of glaciers observed in this region can be more ascribed to a decrease in accumulation (snowfall) than to an increase in surface melting; (2) the melting has only been favoured during winter and spring months and close to the glaciers terminus; (3) a decrease in the probability of snowfall (−10%) has made a significant impact only at glacier ablation zone, but the magnitude of this decrease is distinctly lower than the observed decrease in precipitation; (4) the decrease in accumulation could have caused the observed decrease in glacier flow velocity and the current stagnation of glacier termini, which in turn could have produced more melting under the debris glacier cover, leading to the formation of numerous supraglacial and proglacial lakes that have characterized the region in the last decades.

scholarly journals Improving early epidemiological assessment of emerging Aedes-transmitted epidemics using historical data

2018 ◽  
Author(s):  
Julien Riou ◽  
Chiara Poletto ◽  
Pierre-Yves Boëlle
Keyword(s):  
Historical Data ◽  
A Priori ◽  
Total Duration ◽  
Reproduction Ratio ◽  
Peak Incidence ◽  
Incidence Data ◽  
Epidemic Size ◽  
Data Points ◽  
Final Epidemic Size ◽  
Reporting Rates

AbstractModel-based epidemiological assessment is useful to support decision-making at the beginning of an emerging Aedes-transmitted outbreak. However, early forecasts are generally unreliable as little information is available in the first few incidence data points. Here, we show how past Aedes-transmitted epidemics help improve these predictions. The approach was applied to the 2015-2017 Zika virus epidemics in three islands of the French West Indies, with historical data including other Aedes-transmitted diseases (Chikungunya and Zika) in the same and other locations. Hierarchical models were used to build informative a priori distributions on the reproduction ratio and the reporting rates. The accuracy and sharpness of forecasts improved substantially when these a priori distributions were used in models for prediction. For example, early forecasts of final epidemic size obtained without historical information were 3.3 times too high on average (range: 0.2 to 5.8) with respect to the eventual size, but were far closer (1.1 times the real value on average, range: 0.4 to 1.5) using information on past CHIKV epidemics in the same places. Likewise, the 97.5% upper bound for maximal incidence was 15.3 times (range: 2.0 to 63.1) the actual peak incidence, and became much sharper at 2.4 times (range: 1.3 to 3.9) the actual peak incidence with informative a priori distributions. Improvements were more limited for the date of peak incidence and the total duration of the epidemic. The framework can adapt to all forecasting models at the early stages of emerging Aedes-transmitted outbreaks.

scholarly journals Weak precipitation, warm winters and springs impact glaciers of south slopes of Mt. Everest (central Himalaya) in the last two decades (1994–2013)

2014 ◽  
Vol 8 (6) ◽  
pp. 5911-5959 ◽  
Author(s):  
F. Salerno ◽  
N. Guyennon ◽  
S. Thakuri ◽  
G. Viviano ◽  
E. Romano ◽  
...  
Keyword(s):  
Monsoon Season ◽  
High Elevation ◽  
Maximum Temperature ◽  
Mountain Range ◽  
Central Himalaya ◽  
Climate Trends ◽  
Monsoon Period ◽  
Mean Temperature ◽  
Recent Climate ◽  
Koshi Basin

Abstract. Studies on recent climate trends from the Himalayan range are limited, and even completely absent at high elevation. This contribution specifically explores the southern slopes of Mt. Everest (central Himalaya), analyzing the minimum, maximum, and mean temperature and precipitation time series reconstructed from seven stations located between 2660 and 5600m a.s.l. over the last twenty years (1994–2013). We complete this analysis with data from all the existing ground weather stations located on both sides of the mountain range (Koshi Basin) over the same period. Overall we observe that the main and more significant increase in temperature is concentrated outside of the monsoon period. At higher elevations minimum temperature (0.072 ± 0.011 °C a−1, p < 0.001) increased far more than maximum temperature (0.009 ± 0.012 °C a−1, p > 0.1), while mean temperature increased by 0.044 ± 0.008 °C a−1, p < 0.05. Moreover, we note a substantial precipitation weakening (9.3 ± 1.8mm a−1, p < 0.01 during the monsoon season). The annual rate of decrease at higher elevation is similar to the one at lower altitudes on the southern side of the Koshi Basin, but here the drier conditions of this remote environment make the fractional loss much more consistent (47% during the monsoon period). This study contributes to change the perspective on which climatic driver (temperature vs. precipitation) led mainly the glacier responses in the last twenty years. The main implications are the following: (1) the negative mass balances of glaciers observed in this region can be more ascribed to less accumulation due to weaker precipitation than to an increase of melting processes. (2) The melting processes have only been favored during winter and spring months and close to the glaciers terminus. (3) A decreasing of the probability of snowfall has significantly interested only the glaciers ablation zones (10%, p < 0.05), but the magnitude of this phenomenon is decidedly lower than the observed decrease of precipitation. (4) The lesser accumulation could be the cause behind the observed lower glacier flow velocity and the current stagnation condition of tongues, which in turn could have trigged melting processes under the debris glacier coverage, leading to the formation of numerous supraglacial and proglacial lakes that have characterized the region in the last decades. Without demonstrating the causes that could have led to the climate change pattern observed at high elevation, we conclude by listing the recent literature on hypotheses that accord with our observations.

scholarly journals Diversity and Range of Amphibians of the Yukon Territory

2006 ◽  
Vol 120 (1) ◽  
pp. 87 ◽  
Author(s):  
Brian G. Slough ◽  
R. Lee Mennell
Keyword(s):  
Rana Sylvatica ◽  
First Record ◽  
Yukon Territory ◽  
Wood Frog ◽  
Amphibian Species ◽  
Breeding Sites ◽  
Rana Luteiventris ◽  
Pseudacris Maculata ◽  
Chorus Frog ◽  
Toad Bufo

Four amphibian species occur in the Yukon: Western Toad (Bufo boreas; first verified record in 1961), the Boreal Chorus Frog (Pseudacris maculata, first record in 1995), the Columbia Spotted Frog (Rana luteiventris, first record in 1993), and the Wood Frog (Rana sylvatica; first record in 1933). The Western Toad is restricted to the Liard Basin in five geographically separated areas. Breeding sites have been located on the lower Coal River and vicinity. The Boreal Chorus Frog has been documented from a small area of the lower La Biche River valley near the Yukon-British Columbia-Northwest Territories border. The Columbia Spotted Frog occurs in two widely separated areas, at Bennett Lake in the southwest and in the Liard Basin in the southeast. The Wood Frog is widespread below treeline. Limited survey efforts continue to hinder our knowledge of amphibian distribution. Erratum included.

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