Species climate adaptations on land and sea

Latitudinal extent of realised and potential thermal ranges

In a new study published today in Nature Ecology and Evolution, an international consortium of researchers led by Nikki Moore PhD student at McGill University, sheds light on how temperature shapes the living patterns of cold-blooded animals, revealing that marine species are more directly influenced by thermal limitations compared to their terrestrial counterparts.

The paper explores the distribution of 460 ectothermic species, juxtaposing the temperature ranges and habitats these animals currently occupy with where they could potentially thrive based on their thermal tolerance. Notably, marine organisms are found to inhabit regions that closely align with their thermal tolerances across all latitudes, suggesting a direct response to ocean temperatures.

In contrast, the study found that terrestrial animals like reptiles, amphibians, and insects have ranges that are less determined by temperature, especially at higher latitudes. Many of these land species do not utilize warm, thermally tolerable regions near the equator, implying that factors beyond temperature extremes, such as competitive exclusion, may play a more significant role in shaping their habitats.

This new understanding is crucial in resolving conflicting theories regarding the distribution of life. The observed pattern suggests that higher-latitude terrestrial species are more frequently excluded from tropical areas they can tolerate, hinting at a performance trade-off in colder versus tropical environments.

By illuminating how different species might respond to temperature changes, this research helps us predict and prepare for the shifts in global species distribution as the planet warms. The implications of this work are vital for conservation efforts and for understanding the future of biodiversity in the face of climate change.