Surviving the desert heat

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This week’s featured research article has just been published in Integrative Zoology and examines the thermoregulatory value of cracking-clay soil shelters for small vertebrates during extreme desert conditions in South Australia. Deserts exhibit extreme climatic conditions and small desert-dwelling vertebrates have physiological and behavioural adaptations to cope with these conditions, including the ability to seek shelter. The researchers investigated the temperature and relative humidity regulating properties of the soil cracks that characterize the extensive cracking-clay landscapes of arid SA, and the extent of their use by two small marsupial species: fat-tailed and stripe-faced dunnarts. They measured hourly (over 24-hour periods) of the temperature and relative humidity of randomly-selected soil cracks compared to outside conditions, during two summers and two winters. They tracked 17 dunnarts to quantify their use of cracks. Cracks consistently moderated microclimate, providing more stable conditions than available from non-crack points, which often displayed comparatively dramatic fluctuations in T and RH. Both dunnart species used crack shelters extensively. Cracks constitute important shelter for small animals during extreme conditions by providing a stable microclimate, which is typically cooler than outside conditions in summer and warmer in winter. The researchers conclude that cracks likely play a fundamental sheltering role by sustaining the physiological needs of small mammal populations. Furthermore, globally, cracking-clay areas are dominated by agricultural land uses, including livestock grazing, and so management of these systems should focus not only on vegetation condition, but also on soil integrity, to maintain shelter resources for ground-dwelling fauna. The article can be downloaded here.