Predicting climate change impacts on poikilotherms using physiologically guided species abundance models

Abstract

Poikilothermic animals comprise most species on Earth and are especially sensitive to changes in environmental temperatures. Species conservation in a changing climate relies upon predictions of species responses to future conditions, yet predicting species responses to climate change when temperatures exceed the bounds of observed data is fraught with challenges. We present a physiologically guided abundance (PGA) model that combines observations of species abundance and environmental conditions with laboratory-derived data on the physiological response of poikilotherms to temperature to predict species geographical distributions and abundance in response to climate change. The model incorporates uncertainty in laboratory-derived thermal response curves and provides estimates of thermal habitat suitability and extinction probability based on site-specific conditions. We show that temperature-driven changes in distributions, local extinction, and abundance of cold, cool, and warm-adapted species vary substantially when physiological information is incorporated. Notably, cold-adapted species were predicted by the PGA model to be extirpated in 61% of locations that they currently inhabit, while extirpation was never predicted by a correlative niche model. Failure to account for species-specific physiological constraints could lead to unrealistic predictions under a warming climate, including underestimates of local extirpation for cold-adapted species near the edges of their climate niche space and overoptimistic predictions of warm-adapted species.

Effect of temperature on growth, survival, and chronic stress responses of Arctic Grayling juveniles

“…These models often depict a unimodal, curvilinear relationship between performance and temperature, with a minimum temperature for growth (critical thermal minimum [CT min ]), and as temperature rises, performance increases until an optimum is reached (thermal optimum [T opt ]) beyond which performance decreases until it reaches an upper thermal limit (critical thermal maximum [CT max ]) at which growth is not possible. The general shape of a thermal performance curve (TPC), while remaining consistent across most studies of salmonids (Jonsson et al 2001;Forseth et al 2009;Perry et al 2015), is subject to alterations due to factors such as adaptive evolution or phenotypic plasticity (Sinclair et al 2016;Malusare et al 2023;Wagner et al 2023), which shifts the estimated T opt (Schulte et al 2011). Thermal performance curves are robust and flexible models that are capable of assessing a variety of biological rates, such as speed, stamina, photosynthesis, feeding rate, and growth, to evaluate a species' performance in response to temperature (Sinclair et al 2016;Monaco et al 2017;Padfield et al 2021).…”

Acclimation capacity of critical thermal maximum varies among populations: Consequences for estimates of vulnerability

“…Previous research has demonstrated population variation in tadpole CTmax for both Ascaphus species (Cicchino, Shah, et al, 2023) and generally low thermal tolerances compared with other frogs (Bury, 2008; Cicchino, Shah, et al, 2023), suggesting sensitivity to increasing temperatures. Many studies have linked thermal physiological traits to population ecology and persistence through stressful temperatures (Bernhardt, 2019; Bernhardt et al, 2018; Huey & Kingsolver, 2019; Wagner et al, 2023). However, this system in particular has known population‐level impacts of CTmax on mortality in stressful temperatures, demonstrating that even a 1° increase in CTmax can have a large impact on estimated mortality (Cicchino, Ghalambor, & Funk, 2023).…”

Genomic evidence for climatic adaptation in Fejervarya multistriata

“…The hierarchical mechanisms of thermal limitation (HMTL) hypothesis posited that the limited performance of amphibians in elevated temperatures could be attributed to failures at the subcellular and organ-system levels (Gangloff & Telemeco, 2018). Several studies utilising species abundance prediction model have also indicated a strong correlation between the rising extinction risk of amphibians and global warming (Pigot et al, 2023;Wagner et al, 2023). Therefore, the observed significant decline trend of F. multistriata within Southwestern China during the last interglacial period in our study may be partially attributed to increased climatic temperature.…”