As global warming continues to rise, desert lizards are experiencing an energy crisis. These reptiles rely on external temperatures to regulate their body functions, including how much energy they need and when they can forage for food.
A recent study published in the journal Science reveals that climate change is severely disrupting this balance.
Cold-blooded animals, like lizards, rely on external temperatures to regulate their body heat. Their body temperature directly affects how much energy they need and when they can be active.
In hot desert environments, food is already scarce, and extreme heat can make it too dangerous for lizards to go out and forage.
Climate change is making this problem worse. As temperatures rise, lizards need more energy just to survive because their metabolism speeds up.
However, they also have less time to find food because the heat forces them to stay in shaded or underground areas for longer periods. This creates a difficult situation where their food needs increase, but the lizards’ ability to meet those needs decreases, putting their survival at risk.
“Cost-of-living is a concept humans are all too aware of, but the same concept applies to ectotherms – or cold-blooded animals – such as lizards,” noted study lead author Dr. Kristoffer Wild from the University of Melbourne.
“We just need to switch the currency from money to energy and realize that for lizards these costs and their ability to meet them depend on temperature.”
The researchers found that diurnal (day-active) lizards are especially vulnerable to rising global warming. These lizards depend on daylight hours to hunt for food and sustain their energy levels.
However, as temperatures increase, extreme heat makes it unsafe for the lizards to remain active for long periods. To avoid overheating, they are forced to retreat into shaded areas, burrows, or underground shelters.
The reduction in active hours significantly limits their ability to search for and consume food. Since desert lizards require a certain amount of energy to survive, the loss of foraging time creates a major challenge.
They must find enough food in a shorter window while their energy demands continue to rise due to higher body temperatures.
As a result, diurnal lizards are struggling more than ever in desert environments that are becoming even hotter. With less time to find food and increasing energy needs, their survival is at risk.
If temperatures continue to rise, these lizards may face population declines as they fail to meet their basic nutritional requirements.
In contrast, nocturnal (night-active) lizards may actually benefit from warmer temperatures. Since they are active after sunset, higher nighttime temperatures could extend their hunting periods, giving them more opportunities to find food.
This could help them compensate for the increased energy demands caused by climate change, putting them in a better position to adapt compared to their diurnal counterparts.
Dr. Wild likens this imbalance to a financial crisis. “It’s like diurnal lizards paying higher bills with fewer work hours, while nocturnal lizards can counter high bills by gaining extra work hours during the warmer nights.”
To measure these impacts, the researchers developed a model combining physics and biology.
“We were able to reconstruct, within two or three degrees, what a field biologist observed in the middle of the Australian and African deserts more than 50 years ago. This gives us confidence to predict the direct effects of climate warming on these animals in the future,” explained co-author Professor Michael Kearney.
The findings suggest that desert lizards in historically warmer regions will face greater challenges. Africa’s desert lizards, for instance, will need more food but have less time to find it compared to their Australian counterparts.
The researchers emphasize that conservation strategies must be customized based on each species’ unique foraging habits. Climate change does not affect all animals in the same way – some species will struggle more than others.
This means that a one-size-fits-all approach to conservation is not effective. Instead, targeted efforts are needed to address the specific challenges faced by different lizard species.
“If we can better understand the ecological processes underpinning these cost-of-living pressures, we can better anticipate the species most at risk and act accordingly,” said Professor Kearney.
Survival of desert lizards in a warming climate
However, rising temperatures are not the only threat. Other climate-related issues, such as food shortages and increasing water needs, add to the stress on desert reptiles.
These challenges become even more severe in the warmer months – spring and summer – which are also the critical breeding seasons for many species.
If lizards cannot find enough food and water during this time, their ability to reproduce and maintain stable populations will be threatened. Addressing these combined pressures is essential for ensuring the survival of desert lizard species in a rapidly changing climate.
“Our next steps will be to bring food and water resources into our calculations and translate the results into growth and reproduction, which will help us predict whether populations will survive further change under warming,” Dr. Wild said.
The study highlights the urgent need to understand and address the effects of climate change on desert ecosystems. As temperatures continue to rise, species that rely on delicate energy balances are at increasing risk.
By predicting how different species will respond to these environmental shifts, scientists can develop better conservation strategies. This research is essential for protecting vulnerable desert lizard populations and ensuring their survival in a rapidly warming world.
The study is published in the journal Science.
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