Future of Mammals Unknown Amid Perils of Climate Change, Study Finds

In evolutionary terms, mammals are arguably the most successful group in the history of the planet, colonizing virtually all terrestrial and most aquatic habitats. But little is known about how most mammals will respond to climate change.

(CN) — Nearly one in four mammal species face extinction — a risk exacerbated by climate change. But significant gaps in scientific knowledge persist on how mammal populations are responding to rapid environmental changes from global warming, according to a study published Wednesday in the British Ecological Society’s Journal of Animal Ecology.

The lack of knowledge is particularly acute in regions most sensitive to climate change, a team of scientists from 15 different institutions discovered.

In evolutionary terms, mammals are arguably the most successful group in the history of the planet, colonizing virtually all terrestrial and most aquatic habitats. They’re found everywhere, from the depths of the oceans to some of the tallest mountains on Earth, and even in the air, helped by their range of strategies to cope with difficult conditions.

But climate change is complex, and the ways it impacts animal populations can be contradictory at times, hindering certain aspects of a species survival while boosting others, such as reproduction and other demographic rates, along with such climate variables as rainfall and temperature that scientists use to measure their chance of survival.

However, most studies on terrestrial mammals examine one demographic rate at a time, obscuring the full picture of climate change impacts, researchers found.

In a search of 5,728 mammal species, researchers found only 106 studies that assessed both survival and reproduction simultaneously.

“Researchers often publish results on the effects of climate on survival or on reproduction — and not both,” said lead author Maria Paniw, of the University of Zurich in Switzerland, in a statement. “But only in rare cases does a climatic variable (say, temperature) consistently negatively or positively affect all studied rates of survival and reproduction.”

For example, rising temperatures could reduce the number of offspring, but if less competition boosts the young’s chance of survival, the population size won’t necessarily decrease. However, if higher temperatures cut both reproduction and survival rates, a study of only one of these could underestimate the impact on a population.

While efforts in the last decade have increased the amount of comparative data, little is known about climate impacts in the most climate-vulnerable regions of the globe, researchers determined.

“We were surprised by the lack of data on high-altitude (alpine) mammals,” Paniw noted. “Climate change is expected to be very pronounced in higher elevations.”

The review found information on a few alpine species, such as yellow-bellied marmots and plateau pikas, but none on iconic species such as snow leopards. Such disparities highlight the need for more mammal population research that accounts for multiple demographic responses across entire life cycles.

“To inform evidence-based conservation, we need to prioritize more holistic approaches in data collection and integration to understand the mechanisms that drive population persistence.” Paniw urged.

There are many reasons why this vital data isn’t collected. Such efforts require long-term investment without immediate returns, an approach that most funding agencies don’t favor. These challenges are compounded in climate-vulnerable regions, which include countries with underfunded infrastructure for long-term ecological research.

Researchers are concerned that even bigger data gaps exist for animal groups that are less well studied than land mammals, such as insects and amphibians. Without sufficient data, scientists can’t identify which species are most vulnerable to climate-driven extinction.

Researchers hope to perform similar reviews on less well studied animal groups.

“I would like to foster collaborations that will jumpstart new research and ‘repurpose’ existing data in climate-vulnerable areas of the globe to fill the knowledge gaps we identified in our work,” Paniw stated.