scholarly journals A simple explanation for declining temperature sensitivity with warming

2021 ◽  
Author(s):  
E. M. Wolkovich ◽  
J. L. Auerbach ◽  
C. J. Chamberlain ◽  
D. M. Buonaiuto ◽  
A. K. Ettinger ◽  
...  
Keyword(s):  
Climate Change ◽  
Temperature Sensitivity ◽  
Biological Response ◽  
Critical Threshold ◽  
Simple Explanation ◽  
Biological Processes ◽  
Linear Temperature ◽  
Simple Alternative ◽  
Growing Body ◽  
Non Linear

AbstractTemperature sensitivity—the magnitude of a biological response per °C—is a fundamental concept across scientific disciplines, especially biology, where temperature determines the rate of many plant, animal and ecosystem processes. Recently, a growing body of literature in global change biology has found temperature sensitivities decline as temperatures rise (Fuet al., 2015; Güsewell et al., 2017; Piao et al., 2017; Chen et al., 2019; Dai et al., 2019). Such observations have been used to suggest climate change is reshaping biological processes, with major implications for forecasts of future change. Here we present a simple alternative explanation for observed declining sensitivities: the use of linear models to estimate non-linear temperature responses. We show how linear estimates of sensitivities will appear to decline with warming for events that occur after a cumulative thermal threshold is met—a common model for many biological events. Corrections for the non-linearity of temperature response in simulated data and long-term phenological data from Europe remove the apparent decline. Our results show that rising temperatures combined with linear estimates based on calendar time produce observations of declining sensitivity—without any shift in the underlying biology. Current methods may thus undermine efforts to identify when and how warming will reshape biological processes.Significance statementRecently a growing body of literature has observed declining temperature sensitivities of plant leafout and other events with higher temperatures. Such results suggest that climate change is already reshaping fundamental biological processes. These temperature sensitivities are often estimated as the magnitude of a biological response per °C from linear regression. The underlying model for many events—that a critical threshold of warmth must be reached to trigger the event—however, is non-linear. We show that this mismatch between the statistical and biological models can produce the illusion of declining sensitivities with warming using current methods. We suggest simple alternative approaches that can better identify when and how warming will reshape biological processes.

scholarly journals Regime Shifts in Glacier and Ice Sheet Response to Climate Change: Examples From the Northern Hemisphere

2021 ◽  
Vol 3 ◽  
Author(s):  
Shawn J. Marshall
Keyword(s):  
Climate Change ◽  
Freezing Point ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Regime Shifts ◽  
Glacier Mass Balance ◽  
Polar Regions ◽  
Linear Temperature ◽  
Recent Climate ◽  
Non Linear

Glaciers and ice sheets are experiencing dramatic changes in response to recent climate change. This is true in both mountain and polar regions, where the extreme sensitivity of the cryosphere to warming temperatures may be exacerbated by amplification of global climate change. For glaciers and ice sheets, this sensitivity is due to a number of non-linear and threshold processes within glacier mass balance and glacier dynamics. Some of this is simply tied to the freezing point of water; snow and ice are no longer viable above 0°C, so a gradual warming that crosses this threshold triggers the onset of melting or gives rise to an abrupt regime shift between snowfall and rainfall. Other non-linear, temperature-dependent processes are more subtle, such as the evolution from polythermal to temperate ice, which supports faster ice flow, a shift from meltwater retention to runoff in temperate or ice-rich (i.e., heavily melt-affected) firn, and transitions from sublimation to melting under warmer and more humid atmospheric conditions. As melt seasons lengthen, there is also a longer snow-free season and an expansion of glacier ablation area, with the increased exposure of low-albedo ice non-linearly increasing melt rates and meltwater runoff. This can be accentuated by increased concentration of particulate matter associated with algal activity, dust loading from adjacent deglaciated terrain, and deposition of impurities from industrial and wildfire activity. The loss of ice and darkening of glaciers represent an effective transition from white to grey in the world's mountain regions. This article discusses these transitions and regime shifts in the context of challenges to model and project glacier and ice sheet response to climate change.

Climate change refugia: landscape, stand and tree-scale microclimates in epiphyte community composition

2021 ◽  
Vol 53 (1) ◽  
pp. 135-148
Author(s):  
Christopher J. Ellis ◽  
Sally Eaton
Keyword(s):  
Climate Change ◽  
Community Composition ◽  
Large Scale ◽  
Biological Response ◽  
Tree Age ◽  
Local Effects ◽  
Vulnerability To Climate Change ◽  
Or Gene ◽  
Water Holding ◽  
Epiphyte Community

AbstractThere is growing evidence that species and communities are responding to, and will continue to be affected by, climate change. For species at risk, vulnerability can be reduced by ensuring that their habitat is extensive, connected and provides opportunities for dispersal and/or gene flow, facilitating a biological response through migration or adaptation. For woodland epiphytes, vulnerability might also be reduced by ensuring sufficient habitat heterogeneity, so that microhabitats provide suitable local microclimates, even as the larger scale climate continues to change (i.e. microrefugia). This study used fuzzy set ordination to compare bryophyte and lichen epiphyte community composition to a large-scale gradient from an oceanic to a relatively more continental macroclimate. The residuals from this relationship identified microhabitats in which species composition reflected a climate that was more oceanic or more continental than would be expected given the prevailing macroclimate. Comparing these residuals to features that operate at different scales to create the microclimate (landscape, stand and tree-scale), it was possible to identify how one might engineer microrefugia into existing or new woodland, in order to reduce epiphyte vulnerability to climate change. Multimodel inference was used to identify the most important features for consideration, which included local effects such as height on the bole, angle of bole lean and bark water holding capacity, as well as tree species and tree age, and within the landscape, topographic wetness and physical exposure.

Selection of models to describe the temperature-dependent development of Neoleucinodes elegantalis (Lepidoptera: Crambidae) and its application to predict the species voltinism under future climate conditions

2021 ◽  
pp. 1-9
Author(s):  
Hevellyn Talissa dos Santos ◽  
Cesar Augusto Marchioro
Keyword(s):  
Climate Change ◽  
Linear Model ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Temperature Dependent ◽  
Dependent Development ◽  
Degree Day ◽  
Non Linear ◽  
The Impact

Abstract The small tomato borer, Neoleucinodes elegantalis (Guenée, 1854) is a multivoltine pest of tomato and other cultivated solanaceous plants. The knowledge on how N. elegantalis respond to temperature may help in the development of pest management strategies, and in the understanding of the effects of climate change on its voltinism. In this context, this study aimed to select models to describe the temperature-dependent development rate of N. elegantalis and apply the best models to evaluate the impacts of climate change on pest voltinism. Voltinism was estimated with the best fit non-linear model and the degree-day approach using future climate change scenarios representing intermediary and high greenhouse gas emission rates. Two out of the six models assessed showed a good fit to the observed data and accurately estimated the thermal thresholds of N. elegantalis. The degree-day and the non-linear model estimated more generations in the warmer regions and fewer generations in the colder areas, but differences of up to 41% between models were recorded mainly in the warmer regions. In general, both models predicted an increase in the voltinism of N. elegantalis in most of the study area, and this increase was more pronounced in the scenarios with high emission of greenhouse gases. The mathematical model (74.8%) and the location (9.8%) were the factors that mostly contributed to the observed variation in pest voltinism. Our findings highlight the impact of climate change on the voltinism of N. elegantalis and indicate that an increase in its population growth is expected in most regions of the study area.

scholarly journals Significance of soil respiration from biological activity in the degradation processes of different types of organic matter

2020 ◽  
Vol 1 (2) ◽  
pp. 171-179
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Temperature Sensitivity ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Total Soil

Soil respiration is a major component of global carbon cycle. Therefore, it is crucial to understand the environmental controls on soil respiration for evaluating potential response of ecosystems to climate change. In a temperate deciduous forest (located in Northern-Hungary) we added or removed aboveground and belowground litter to determine total soil respiration. We investigated the relationship between total soil CO2 efflux, soil moisture, and soil temperature. Soil CO2 efflux was measured at each plot using soda-lime method. Temperature sensitivity of soil respiration (Q10) was monitored via measuring soil temperature on an hourly basis, while soil moisture was determined monthly. Soil respiration increased in control plots from the second year after implementing the treatment, but results showed fluctuations from one year to another. The effect of doubled litter was less significant than the effect of removal. Removed litter and root inputs caused substantial decrease in soil respiration. We found that temperature was more influential in the control of soil respiration than soil moisture. In plots with no litter Q10 varied in the largest interval. For treatment with doubled litter layer, temperature sensitivity of CO2 efflux did not change considerably. The effect of increasing soil temperature is more conspicuous to soil respiration in litter removal treatments since lack of litter causes greater irradiation. When exclusively leaf litter was considered, the effect of temperature on soil respiration was lower in treatments with added litter than with removed litter. Our results reveal that soil life is impacted by the absence of organic matter, rather than by an excess of organic matter. Results of CO2 emission from soils with different organic matter content can contribute to sustainable land use, considering the changed climatic factors caused by global climate change.

scholarly journals Timing of increased temperature sensitivity coincides with nervous system development in winter moth embryos

2021 ◽  
Author(s):  
Natalie E. van Dis ◽  
Maurijn van der Zee ◽  
Roelof A. Hut ◽  
Bregje Wertheim ◽  
Marcel E. Visser
Keyword(s):  
Climate Change ◽  
Temperature Sensitivity ◽  
Development Rate ◽  
Egg Development ◽  
Egg Hatching ◽  
Seasonal Timing ◽  
Winter Moth ◽  
Developmental Progression ◽  
Phylotypic Stage ◽  
Insect Embryos

Climate change is rapidly altering the environment and many species will need to genetically adapt their seasonal timing to keep up with these changes. Insect development rate is largely influenced by temperature, but we know little about the mechanisms underlying temperature sensitivity of development. Here we investigate seasonal timing of egg hatching in the winter moth, one of the few species which has been found to genetically adapt to climate change, likely through selection on temperature sensitivity of egg development rate. To study when during development winter moth embryos are most sensitive to changes in ambient temperature, we gave eggs an increase or decrease in temperature at different moments during their development. We measured their developmental progression and timing of egg hatching, and used fluorescence microscopy to construct a timeline of embryonic development for the winter moth. We found that egg development rate responded more strongly to temperature once embryos were in the fully extended germband stage. This is the phylotypic stage at which all insect embryos have developed a rudimentary nervous system. Furthermore, at this stage timing of ecdysone signaling determines developmental progression, which could act as an environment dependent gateway. Intriguingly, this may suggest that, from the phylotypic stage onward, insect embryos can start to integrate internal and environmental stimuli to actively regulate important developmental processes. As we found evidence that there is genetic variation for temperature sensitivity of egg development rate in our study population, such regulation could be a target of selection imposed by climate change.

scholarly journals An approach for experiment evaluations for multiple harvests crops based on non-linear regression

2021 ◽  
Vol 39 (3) ◽  
pp. 250-257
Author(s):  
Alessandro Dal’Col Lúcio ◽  
Maria Inês Diel ◽  
Bruno G Sari
Keyword(s):  
Linear Regression ◽  
Growth Models ◽  
Fruit Production ◽  
Production Cycle ◽  
Total Production ◽  
Biological Processes ◽  
Production Potential ◽  
Non Linear ◽  
Using Data ◽  
The Moment

ABSTRACT Biologically based growth models can be an alternative in identifying the productive response of multiple harvest vegetables. By interpreting the estimates of the parameters of the models, it is possible to estimate the total production, the rate of fruit production, and the moment when the crop reaches its maximum production potential. Besides, by estimating confidence intervals, these responses can be compared between genotypes or between different treatments. Therefore, the purpose of this manuscript is to present a literature review, and a detailed step-by-step, to interpreting the evolution of the production cycle of vegetables with multiple harvests crops based on non-linear regression. All the requirements that must be met in this type of analysis were presented in detail based on non-linear regression, providing the necessary steps for this type of analysis in details. Demonstration is given using data from strawberry cultivation along with the associated R scripts and interpretation of analysis output in material supplemental. This approach can allow for more relevant inferences than standard means analyses through better examination and modeling of the underlying biological processes.

scholarly journals Personalise Dose Regimen of Vitamin D3 Using Physiologically-Based Pharmacokinetic Modelling

2020 ◽  
Author(s):  
Zhonghui Huang ◽  
Tao You
Keyword(s):  
Vitamin D ◽  
Dose Regimen ◽  
Population Heterogeneity ◽  
Plasma Vitamin ◽  
Simple Explanation ◽  
Pbpk Models ◽  
Physiologically Based Pharmacokinetic ◽  
Physiologically Based ◽  
Non Linear ◽  
Baseline Levels

AbstractBackground and AimVitamin D3 (i.e. cholecalciferol) produces an active metabolite 25-hydroxyvitamin D3 (i.e. 25(OH)D3) to promote intestinal calcium absorption. Given high population heterogeneity in 25(OH)D3 plasma concentration profiles, vitamin D3 dose regimen needs to be personalised. The objective of this study is to establish a model that accurately predicts 25(OH)D3 pharmacokinetics (PK) on an individual level to enable selection of an appropriate dose regimen for anyone.MethodsPlasma or serum concentrations of Vitamin D3 and 25(OH)D3 from different trials were compiled together. We then developed a series of Physiologically-Based Pharmacokinetic (PBPK) models for vitamin D3 and 25(OH)D3 in a stepwise manner to select the best model to optimally recapitulate the 10μg and 100μg daily dose data. Each arm of the clinical trials was simulated individually. Model predictions were qualified with PK data at other doses.ResultsFrom data exploration, we observed an interesting phenomenon: the increase in plasma 25(OH)D3 after repeat dosing was negatively correlated with 25(OH)D3 baseline levels. Our final model assumes a first-order vitamin D3 absorption, linear vitamin D3 elimination and a non-linear 25(OH)D3 elimination which is described with an Emax function. This model offers a simple explanation to the apparent paradox: the negative correlation might arise from the non-linear 25(OH)D3 elimination process. The model was also able to accurately predict plasma 25(OH)D3 after repeat dosing at daily doses other than 10μg and 100μg, which was reassuring.ConclusionsWe developed a PBPK model to recapitulate PK of plasma vitamin D3 and 25(OH)D3. A personalised vitamin D3 supplementation protocol requires measurement of 25(OH)D3 baseline levels. This should be tested in the clinics for each individual.

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