Realistic projections of the biological impacts of climate change require a unified framework capable of integrating advances from distinct research areas such as ecophysiology, behavioural ecology, and biogeography. Mechanistic modelling in macroecology arises as a promising framework to address this challenge, because it aims at describing biodiversity patterns from biophysical, physiological, and behavioural processes determining the way organisms interact with their environment. Nonetheless, mechanistic modelling face further challenges such as the need to connect processes across scales and levels of ecological organization.

SCALE is a Marie-Curie funded project that investigates how organismal-microclimate interactions influence broad-scale patterns and thermal adaptations of ectotherms, a group that is especially vulnerable to global change, across climatic gradients.

The project brings together three researchers with backgrounds in evolutionary ecology and modelling (Juan G. Rubalcaba, postdoctoral fellow), and macroecology (Jennifer Sunday, supervisor at McGill University, Montreal) and Miguel Á. Ollala-Tárraga (supervisor at Rey Juan Carlos University, Madrid).

The biophysics of body size and climate

Body size is one of the most important variables determining how animals interact with their environment, modulating their physiology, metabolism, behaviour, and life history. Most of these traits scale with size following specific "allometric rules" governed by physical processes such as the exchange of energy (heat) and mass (water, oxygen, or nutrients) between the animal and its environment. This may sound just as a "nice theory", but understanding these processes is critical to explain, for example, why many organisms are smaller in warmer areas, and why many animals are shrinking body size in response to climate warming.

SCALE uses biophysical models that describe how animals exchange heat and mass with their environments to predict how body size determines body temperature of lizards, water loss in amphibians, or the dynamics of oxygen demand and supply in aquatic ectotherms such as fish.