Crave crisis: African bats face survival threat as habitats vanish

Climate change and land-use changes are the two biggest threats to wildlife, altering the environments where animals survive. Knowing how species respond is central to planning conservation actions.

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Several studies have modelled how climate change affects vertebrate distributions. However, little is known about bats from tropical and subtropical regions, especially in Africa.

Bats are particularly sensitive to environmental changes due to slow reproductive rates, dependence on stable roosts, and sensitivity to climatic extremes affecting insect availability. They need suitable foraging landscapes and caves for roosting. Research has examined how climate change affects bats, but it has overlooked a key fact: cave-dependent bats cannot survive in climatically suitable areas without access to suitable roosts.

Even if a future landscape has the right temperature and rainfall, it is useless if there is nowhere to roost. What happens when places with the right climate lack caves?

Having studied bats since 2017, I have spent much of my research career investigating their ecology and habitat dependence. This experience led me to question where climate change might push wildlife, and whether Africa's cave-dwelling bats can find somewhere to live as the climate changes.

My co-author Mark Keith and I built a model combining future climate conditions with the availability of caves and rocky roosting habitats across sub-Saharan Africa. We used cave-dwelling long-fingered bats (Miniopteridae) as our study group. Found widely across Africa, they depend heavily on caves and commonly occur alongside other cave-dwelling bat species.

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Our findings suggest Africa's cave-dwelling bats face a double challenge. Climate change could shrink the areas where they can live, but even where future conditions remain suitable, caves might be absent. Safe havens will require three elements: suitable climate, available shelter, and movement corridors between sites.

We used an existing database of 551 reliable records across sub-Saharan Africa. Using a computer model, we matched each site with its local climate to determine what conditions the bats need, then projected where those conditions would exist around 2070 under a moderate warming scenario.

Depending on climate shifts in coming decades, suitable areas for these bats could shrink by 36% to 64% by 2061-2080. Remaining suitable areas were concentrated mainly in southern Africa, the eastern highlands, and Madagascar.

However, when comparing suitable future climates with locations of suitable caves and rocky landscapes, the picture became alarming. Only around 5% of areas with suitable caves had a climate expected to remain suitable. When accounting for landscape vulnerability to future change, that figure fell to around 2%. The places with the right climate and those with available homes barely overlapped. Furthermore, survival depends on a network of caves spread across the landscape for seasonal movement.

These findings apply broadly across wildlife. As the climate changes, suitable conditions may shift, but specific habitats may not. Conservation planning must ask not only where climate will be suitable, but whether species will actually have somewhere to live.

Mariëtte van der Walt is Biodiversity Coordinator, Wilderness, University of the Witwatersrand