Protecting India's tigers also good for climate: study
By Juliette COLLEN
Paris (AFP) May 25, 2023

India's efforts to protect its endangered tigers have inadvertently helped avoid a large amount of climate change-causing carbon emissions by preventing deforestation, a study said on Thursday.

Three-quarters of the world's wild tigers live in India, but the destruction of their natural habitat have seen their numbers plummet.

The number of tigers roaming the country's forests fell from 40,000 when India gained independence in 1947 to just 1,500 in 2006.

However their number rose above 3,000 this year, according to the latest official figures.

To help their numbers rebound, India has designated 52 tiger reserves where logging and deforestation are heavily regulated.

Aakash Lamba, a researcher at the National University of Singapore and the new study's lead author, told AFP that tigers are an "umbrella species".

This "means that by protecting them we also protect the forests they live in, which are home to an incredible diversity of wildlife," he told AFP.

Forests are a "carbon sink", which mean they absorb more carbon dioxide from the atmosphere than they release, making them a crucial tool in the fight against climate change.

India, the world's third largest emitter of greenhouse gases, has pledged to lower its emissions.

- Million metric tons -

Lamba, who grew up in India, said the team of researchers sought to establish an empirical link between tiger conservation and carbon emissions.

They compared the rate of deforestation in the special tiger reserves to areas where the big cats also live, but are less strictly protected.

More than 61,000 hectares of forest was lost across 162 different areas between 2001 and 2020, according to the study.

More than three quarters of the deforestation was in areas outside of the tiger reserves.

Inside the tiger reserves, almost 6,000 hectares was saved from deforestation between 2007 to 2020. That equates to more than a million metric tons of carbon emissions avoided, the study estimated.

Lamba emphasised the economic impact of those saved emissions in a country that has been hit hard by the effects of climate change -- particularly the agricultural industry.

Taking into account the social cost of those emissions, more than $92 million had been saved, the researchers calculated.

If counted as part of an carbon offset scheme, the avoided deforestation amounted to more than $6 million, they added.

"The financial benefits of avoiding carbon emissions are more than a quarter of the annual expenditure on tiger conservation in India," Lamba said.

"This significant outcome highlights how investments in wildlife conservation not only safeguard ecosystems and wildlife but also benefit societies and economies."

The study was published in the journal Nature Ecology & Evolution.

The findings come after a study published in March suggested protecting or restoring a handful of wild animals such as whales, wolves and otters could help capture 6.4 billion tons of carbon dioxide every year.

Warming Arctic could put chill on squirrel 'date night'
Washington (AFP) May 25, 2023 - As Alaska's bleak winter sets in, arctic ground squirrels burrow deep into the ground to begin an eight-month-hibernation before popping up again in spring, famished and eager to breed.

Scientists studying the critters have now discovered a startling new consequence of climate change: as temperatures rise, females of the species have been gradually advancing the date they re-emerge, now a full 10 days earlier than a quarter century ago.

On the other hand, males are not ending their deep sleep sooner: a fact that could soon spell trouble for "date nights," according to a paper published Thursday in the journal Science.

Males previously terminated hibernation a month before females, allowing enough time for their testicles, which shrivel up every fall, to regrow and descend, in an annual cycle of puberty. But this interval is narrowing.

"If this continues, we expect to start to see females emerging ready to mate with males before those males are actually fully reproductively mature," senior author Cory Williams, a biologist at Colorado State University, told AFP.

- Unique adaptations -

Like many Arctic animals, ground squirrels have evolved to have unique adaptations to the extreme winter.

They hibernate around eight months of the year, digging about three feet (a meter) deep in the sandy banks of rivers, just above the tundra's permafrost.

During this time, their body temperatures drop from about 99 degrees F (37 degrees C) to almost 27F (-3C), the lowest in any mammals, drastically slowing their brain, lungs, heart and other organ functions, in a state called "torpor."

The team behind the study were able to harness long-term air and soil temperature data at two sites, and fused those with data collected from biologgers, which measured abdominal and skin temperatures of 199 ground squirrels over the same period.

They detected a significant increase in ambient temperature, as expected for a region known to be warming from climate change at a rate four times greater than the global average.

"The minimum soil temperatures in winter are warmer. It's not getting as cold," said Williams. "And then we also saw a change in the freeze-thaw cycle of the soil. So the soils are now freezing later, and they're thawing earlier."

This had two effects on the animals.

Though they entered hibernation at the same time, the point at which their core body temperature fell below 32F (0C) was delayed, which in turn pushed back the date at which they need to generate heat to prevent tissue death during torpor, an energy-intensive process.

Second, females ended hibernation earlier, matching the earlier spring thaw.

Exactly why this second effect impacts females only isn't confirmed, but the scientists have some theories.

For males, rising testosterone levels as they prepare to breed in spring appear to force an end to hibernation at a fixed point, but females seem more responsive to environmental conditions.

"We've found that females will sometimes end hibernation, and then they'll go to the surface and assess conditions, and they'll go back down and re-enter hibernation when there's what we assume is too much snowpack," said Williams.

- Fatter, but more exposed to predators -

The advantage of this reduced hibernation was that females emerged with more mass, and could get a head start on foraging for roots, shoots, berries and seeds. This in turn could produce healthier litters and better survival rates.

On the other hand, they are exposed for a longer period to their predators -- golden eagles, gyrfalcons, foxes and wolves -- in addition to the looming disruption in sexual interactions.

There could also be cascading impacts up the food chain, if the squirrels' predators adapt to earlier prey availability by advancing their own breeding season.

It's too soon to say, then, what the overall impacts might be.

But what is striking is the concrete proof of climate directly impacting an ecosystem over a relatively short period of time, said first author Helen Chmura, a US Department of Agriculture Forest Service researcher.

"We have a 25-year-dataset, which is a fairly long term thing for science but that's a short period of time in ecology," she told AFP. "We have evidence of effects on ecosystems within the time span of people's lives, including young people."

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