A core challenge in global change biology is to predict how species will respond to future environmental change and to manage these responses. To make such predictions and management actions robust to novel futures, we need to accurately characterize how organisms experience their environments and the biological mechanisms by which they respond. All organisms are thermodynamically connected to their environments through the exchange of heat and water at fine spatial and temporal scales and this exchange can be captured with biophysical models. Although mechanistic models based on biophysical ecology have a long history of development and application, their use in global change biology remains limited despite their enormous promise and increasingly accessible software. We contend that greater understanding and training in the theory and methods of biophysical ecology is vital to expand their application. Our review shows how biophysical models can be implemented to understand and predict climate change impacts on species' behavior, phenology, survival, distribution, and abundance. It also illustrates the types of outputs that can be generated, and the data inputs required for different implementations. Examples range from simple calculations of body temperature at a particular site and time, to more complex analyses of species' distribution limits based on projected energy and water balances, accounting for behavior and phenology. We outline challenges that currently limit the widespread application of biophysical models relating to data availability, training, and the lack of common software ecosystems. We also discuss progress and future developments that could allow these models to be applied to many species across large spatial extents and timeframes. Finally, we highlight how biophysical models are uniquely suited to solve global change biology problems that involve predicting and interpreting responses to environmental variability and extremes, multiple or shifting constraints, and novel abiotic or biotic environments.

The possible role of climate change in late Quaternary animal extinctions is hotly debated, yet few studies have investigated its direct effects on animal physiology to assess whether past climate changes might have had significant impacts on now‐extinct species. Here we test whether climate change could have imposed physiological stress on the Tasmanian devil Sarcophilus harrisii during the mid‐Holocene, when the species went extinct on mainland Australia. Physiological values for the devil were quantified using mechanistic niche models of energy and water requirements for thermoregulation, and soil‐moisture‐based indices of plant stress from drought to indirectly represent food and water availability. The spatial pervasiveness, extremity and frequency of physiological stresses were compared between a period of known climatic and presumed demographic stability (8000–6010 BP) and the extinction period (5000–3010 BP). We found no evidence of widespread negative effects of climate on physiological parameters for the devil on the mainland during its extinction window. This leaves cultural and demographic changes in the human population or competition from the dingo Canis dingo as the main contending hypotheses to explain mainland loss of the devil in the mid‐Holocene.

We use fossil, sub‐fossil and contemporary records of the Broad‐toothed rat, Mastacomys fuscus, to model changes in its range over the last 21 thousand years. Mastacomys fuscus was exposed to, and flourished in, a much broader range of environmental conditions in the recent past than it occupies today. It also currently occupies a much smaller range than it did in the Late Pleistocene. Apart from a weak response to sea‐level rise in the Holocene, the decline of M. fuscus does not correlate with known climate change. Instead, the contraction of the species' distribution on mainland Australia to high‐elevation areas occurred recently and rapidly. Small changes in the 1000 year BP and present‐day projected distributions imply some contraction of the area of suitable climate to higher elevations of the mainland subspecies M. f. mordicus, up to 2200 m above sea level. However, M. f. mordicus also persists near sea level at Cape Otway (southwestern Victoria) and from sea level to 1500 m above sea level at Barrington Tops (eastern New South Wales, Australia). This suggests suitable habitat may still exist in coastal Victoria and the central Tablelands/Blue Mountains areas. This research highlights the importance and value of using sub‐fossil data to understand changes in the distribution and niche occupation of threatened species as the basis for conservation planning.

Translocations—the movement of species from one place to another—are likely to become more common as conservation attempts to protect small isolated populations from threats posed by extreme events such as bushfires. The recent Australian mega-fires burnt almost 40% of the habitat of the brush-tailed rock-wallaby (Petrogale pencillata), a threatened species whose distribution is already restricted, primarily due to predation by invasive species. This chronic threat of over-predation, coupled with the possible extinction of the genetically distinct southern population (approx. 40 individuals in the wild), makes this species a candidate for a conservation translocation. Here, we use species distribution models to identify translocation sites for the brush-tailed rock-wallaby. Our models exhibited high predictive accuracy, and show that terrain roughness, a surrogate for predator refugia, is the most important variable. Tasmania, which currently has no rock-wallabies, showed high suitability and is fox-free, making it a promising candidate site. We outline our argument for the trial translocation of rock-wallaby to Maria Island, located off Tasmania's eastern coast. This research offers a transparent assessment of the translocation potential of a threatened species, which can be adapted to other taxa and systems.

Hibernation is an important strategy used by many endotherms to conserve energy and water. Global warming is changing species' phenology and hibernation patterns, but whether such changes are beneficial or harmful depends on the species' life history traits, physiology, morphology, and behavior. Mechanistic niche models can be used to make strong inferences on such responses by explicitly quantifying the consequences of changed hibernation patterns for energy and water requirements. However, they have yet to be adapted to heterothermic species. Here, we address this problem by extending the endotherm biophysical model of the NicheMapR package to encompass torpor. This model accurately predicts the energy requirements of hibernating mammals over a broad size range from microbats to bears. We then used this approach to assess the effect of climate change on a Critically Endangered hibernator, the Australian mountain pygmy possum ( Burramys parvus ). Specifically, we contrasted conditions for the year 2010 with two future climate‐change scenarios (2or 4°C of average warming) to identify: (i) the projected changes in energy and water requirements; (ii) the advantage conferred by hibernating for the species' energy and water requirements; and (iii) the areas across southeastern Australia that could continue to support hibernation. We projected an 11%–43% reduction in hibernation hours for the mountain pygmy possum under our two climate‐change scenarios. In consequence, requirements for energy increased by 4%–21%, and for water by 10%–34%. Under current conditions, hibernation reduces annual energy requirements by 44%–52% and annual water requirements by 32%–42%, but in our projections, this energetic and hydric benefit of hibernation will decline due to climate change. The total area where hibernating and not hibernating is energetically equivalent is projected to increase by 60% under 4°C warming, preventing recovery from the species' severely restricted distribution at present. Our results show that climate change will have a profound impact on the duration and patterns of hibernation, a key survival strategy, for Burramys . Our framework for analyzing changing hibernation patterns provides a new and general way to test the vulnerability and plasticity of hibernating endotherms under global change.