H2020 SCALE Project: Projecting global biodiversity responses from biological first principles
- Type Project
- Status Filled
- Execution 2019 -2022
- Assigned Budget 232.497,6 €
- Scope Europeo
- Autonomous community Madrid, Comunidad de
- Main source of financing Horizon 2020
- Project website https://doi.org/10.3030/843094
The productivity and growth rates of forests, crops, and wild vegetation around the world have gradually increased due to the concentration of carbon dioxide (CO2) in the air. As these concentrations continue to rise, plants are likely to respond by growing more robustly and expanding their ranges. Realistic projections of the biological impacts of climate change require a unified framework capable of integrating advances from diverse research areas.
The EU-funded SCALE project aims to closely examine how heat and water transfer mechanisms determine global patterns of species richness and thermal adaptations of terrestrial ectotherms, a group that is particularly vulnerable to global change. The SCALE project has achieved its proposed impacts, including the development and dissemination of different mechanistic models to predict organism-environment interactions under current and future climate scenarios. Our research has been published in high-impact multidisciplinary journals such as the Proceedings of the National Academy of Sciences, achieving significant media coverage.
- Modeling the Direction and Constraints on Functional Trait Evolution in Reptiles We developed biophysical models to predict body temperature and physiological performance in reptiles and used them to investigate how thermal performance varies in response to climate among species with different body sizes, skin colors, thermoregulatory capacity, and physiological tolerance. This global analysis allowed us to numerically predict the direction and strength of selection on different functional traits. To test these predictions, we coordinated different experts in macroecology and thermal physiology and compared predicted versus observed patterns using published data from over 1200 reptile species. We found that the models accurately predict the direction and strength of the effect of climate on different functional traits at a global scale.
- Modeling the Large-Scale Responses of Tropical Ectotherms to Climate Change Many ectotherms, such as lizards, exploit the heterogeneity of their environments to behaviorally control body temperature, for example, by moving between sun-exposed and shaded microenvironments. However, we lack a method to quantify this behavioral buffering capacity at large scales. We use our ectotherm biophysical model to assess the potential for behavioral thermoregulation to buffer body temperature against climate change in forest-dwelling Neotropical lizards, a group that is especially vulnerable to warming. We find that the projected increase in ambient temperatures in the Amazon could exceed the lizards’ estimated maximum buffering capacity. Our approach allows, for the first time, to calculate the capacity of tropical lizards to buffer the impacts of warming, a critical milestone toward designing effective management strategies to reduce the vulnerability of these species to climate and habitat change.
- Modeling Metabolic Rate and the Response of Aquatic Ectotherms to Climate Change Organismal responses to climate change are mediated by their effects on physiology. In aquatic environments, both water temperature and oxygen availability can modulate these responses by altering the metabolism that fuels physiological performance. However, ecological models intended to predict how environmental factors shape aerobic metabolism ignore the role of oxygen supply. We developed a biophysical model to investigate how oxygen uptake capacity affects the response of aquatic ectotherms to climate warming. In a comparative analysis across fish species, we demonstrate that the model accurately predicts complex interactions between body size and temperature on the aerobic range of fish. Our results suggest that larger species may be more restricted than smaller species in warming waters due to physical limitations on oxygen uptake capacity.
- Modeling the Costs of Thermoregulation in Endotherms Biophysical heat balance models can estimate the metabolic cost required for an endothermic organism, such as a bird or mammal, to maintain a constant body temperature in a variable environment. We use biophysical models to address the outstanding question in macroecology of why bat body size does not follow the geographic and evolutionary patterns observed among non-flying mammals. By modeling the costs of thermoregulation and the costs of flight, we find that these costs are similar to those that limit body size and shape, especially in colder climates. By analyzing the size and shape of 278 bat species, we find that morphological evolution in bats varies with climate and that the strength of selection is stronger in colder regions than in warmer regions, consistent with the model prediction. These results shed light on a long-standing debate about bats' conformity to macroevolutionary patterns observed in other mammals and offer a novel procedure for investigating complex macroecological patterns from first principles.
- Organization of workshops and communication activities A key objective of SCALE is to disseminate mechanistic modeling approaches among researchers from different disciplines, such as physiology and macroecology, and from different systems, such as terrestrial and aquatic environments. To achieve this, we organized two workshops presenting the use of microclimatic and biophysical models in modeling species distributions and predicting climate change impacts (IBS 2022, CSEE 2021). Furthermore, to reach a wider, non-specialist audience, we launched a blog presenting the most relevant results of the project and developed two "Shiny Apps" in R to allow any user to interact with the biophysical models online.
Predicting organisms' responses to global climate and habitat change remains a priority for ecological research. Reliable projections of these responses require the integration of information on the physiological and behavioral traits that determine organisms' ability to buffer or adapt to environmental changes. However, most of our current predictive tools rely on phenomenological models based on observed correlations between organisms and environments, with limited ability to predict organisms' performance under unprecedented environmental conditions.
In macroecology, the study of the relationships between organisms and their environment at large spatial scales, mechanistic approaches are emerging. Unlike phenomenological models, these mechanistic models rely on the physical principles of energy and mass transfer and physiological information to predict how key state variables, such as body temperature, metabolic rate, or water balance, respond to climate across space and time.
Despite their potential, mechanistic models face significant challenges in macroecology, such as the problem of how to scale individual metrics to higher levels of ecological organization, such as populations and species assemblages. SCALE adopts a mechanistic perspective to investigate how heat and mass balances scale up in macroecological and macroevolutionary patterns across different animal taxa, including terrestrial and aquatic ectotherms and endotherms. To achieve this, we develop biophysical models of heat and mass transfer and use cutting-edge computational techniques to simulate the response of multiple species to climate and habitat change.
The overall objectives of SCALE include:
- Develop and disseminate mechanistic models that provide access to newly developed software and organize workshops to facilitate their implementation.
- Validate models that compare predicted versus observed patterns of species functional traits across large-scale climatic gradients.
- Project model predictions into future climate change scenarios.
Realistic projections of the biological impacts of climate change require a unified framework capable of integrating advances from diverse research areas such as ecophysiology, behavioral ecology, and biogeography. Mechanistic modeling in macroecology emerges as a promising framework for addressing this challenge, as it seeks to describe biodiversity patterns based on biophysical, physiological, and behavioral processes that determine how organisms interact with their environment. In this project, I will investigate how heat and water transfer mechanisms determine global patterns of species richness and the thermal adaptations of terrestrial ectotherms, a group particularly vulnerable to global change.
The specific objectives of this proposal are:
- Investigate how temperature regulation and water availability constrain global patterns of reptile and amphibian species richness
- Investigate .
- To predict the response of these patterns to future climate conditions. To achieve these goals, I will combine state-of-the-art biophysical models of heat and water transfer pathways between ectotherms and their environment with empirical data on the species' geographic distribution and thermal tolerance characteristics obtained from the literature.
Ultimately, this proposal will contribute to the emerging field of mechanistic modeling in macroecology, providing methods for integrating multiple sources of biological information and techniques for predicting organismal responses to climate change. Training in the geographic analysis of mechanistic models will boost my development as a leading independent researcher and innovator in macroecology in the EU.
Organisms are thermodynamically connected to their environment through the exchange of heat, water, and/or oxygen. These interactions can be captured with "biophysical models" that integrate information about environmental conditions and organism characteristics to predict how individuals would perform in any given environment. However, these models face challenges, and there is a need to calibrate and validate models by combining their theoretical predictions with empirical observations.
This is where the EU-funded SCALE project, supported by the Marie Skłodowska-Curie Actions Programme, comes in. “Our goal was to contribute to a new modeling framework with which to predict animal responses to environmental change,” explains Juan Rubalcaba, project coordinator. To achieve this, SCALE combined interspecific data, available in ecophysiology, with theoretical predictions generated using biophysical models. It then used the models to predict how physiological traits, such as metabolic rate, should change in response to climatic conditions, and examined whether the project's predictions matched empirical observations.
The Impact of Climate on Lizards There is considerable debate about whether climate directly modulates traits such as body size, skin color, and thermal tolerance. To better understand this, SCALE used a biophysical model to predict the body temperature and physiological performance of theoretical lizards in different climates. "We then used the model to investigate which phenotypes would maximize physiological performance in each region by simulating the effect of natural selection on body size, skin color, thermal tolerance, and thermoregulatory behavior," explains Rubalcaba. The project found that the observed geographic patterns for body mass, cold tolerance, and optimal body temperature were significantly related to their predictions. "Therefore, our results (opens in a new window) suggest that climate directly modulates these traits through its effect on thermal performance," adds Rubalcaba. Oxygen Demand and Supply in Aquatic Ectotherms SCALE developed a biophysical model to investigate oxygen supply and demand in fish, taking into account the physicochemical mechanisms that drive oxygen transfer across the gill surface. "We used the model to investigate the interaction between water temperature, oxygen availability, body size, and activity level on the metabolic rate and physiological performance of fish," Rubalcaba highlights. The model predicts that large, active animals will have a limited ability to obtain the oxygen needed to meet their physiological demand in warmer waters.
Therefore, SCALE results (opens in a new window) suggest that global warming will impair physiological performance, placing a greater metabolic burden on larger individuals in the future. The evolution of body size and shape in bats "We also investigated how body size, wing size, and temperature interact to determine the costs of flight and the costs of thermoregulation. The model shows that large wings reduce flight costs but increase heat dissipation rates, which increases the costs of thermoregulation, especially in cold climates," confirms Rubalcaba. Using morphological data from bat species, SCALE found that the surface area-to-mass ratio of wings evolves towards an optimal shape and that the strength of selection is greater among species that live in cold climates, which is in line with theoretical predictions. Project results (opens in a new window) therefore suggest that climate influences the evolution of body size in bats through its effect on energy demand. These results demonstrate that climate has a direct influence on energy demand and physiological performance, which, in turn, ultimately affect the evolution of phenotypic traits. "Furthermore, biophysical models can capture the key mechanisms driving interactions between organisms and the climate and can therefore be used to predict organisms' responses to climate change," Rubalcaba concludes.
- UNIVERSIDAD REY JUAN CARLOS
- ROYAL INSTITUTION FOR THE ADVANCEMENT OF LEARNING MCGILL UNIVERSITY
- CORDIS project factsheet (pdf)
- Web researcher
- Physical constraints on thermoregulation and the morphological evolution of fli…
- Climate drives global variation in functional traits in lizards
- Oxygen limitation may affect the temperature and size dependence of metabolism …
- Body temperature and activity patterns modulate glucocorticoid levels across li…
- Website of the Rey Juan Carlos University
- ROYAL INSTITUTION FOR THE ADVANCEMENT OF LEARNING MCGILL UNIVERSITY website
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