The Iberian Lynx Is Doomed — Maybe


The world’s most endangered cat is not the lion or cheetah or tiger; it’s the Iberian lynx. Already at risk for a number of reasons I’ll get into below, a new study from Nature Climate Change predicts that the lynx could be extinct by 2060, driven off the planet by anthropogenic climate change.

As its name suggests, the Iberian lynx belongs on the Spanish-Portuguese peninsula, where it exists in a few isolated places in southwestern Spain and perhaps Portugal (though no one really knows). The IUCN estimates the lynx population at a mere 84 to 143 adult cats; recent counts suggest there may be as many as 250 of these kitties. Even the high number is a pretty small population — thus, the classification as Critically Endangered.

The lynx’s habitat has shrunk from 15,700 square miles in the 1950s to just 460 square miles, estimated in 2005. Like its North American counterpart, the Iberian lynx depends on rabbit for sustenance, but the cats’ bunny meal, the European rabbit, has gone through a major decline because of disease, hunting, and habitat loss. The lynx have also suffered from people trapping and poaching them, and hitting them with cars. (Generally cars and wild cats do not mix well.)

The good news for the lynx is that they have a lot of fans and conservation efforts have been well funded. There have been captive breeding programs, work towards restoring their bunny prey, and other efforts to make the world more friendly to the Iberian lynx, all in the hope that the cat population can grow larger, or at least not die out.

The problem, say researchers in the new study, is that none of these plans account for climate change. When they created a computer model of the lynx and rabbit populations that included the expected alterations to temperature and precipitation, they discovered that the lynx would die out within the next 50 years.

“Our models show that the anticipated climate change will lead to a rapid and dramatic decline of the Iberian lynx and probably eradicate the species within 50 years, in spite of the present-day conservation efforts. The only two populations currently present will not be able to spread out or adapt to the changes in time,” coauthor Miguel Araújo, an ecologist at the University of Copenhagen, said in a statement.

All hope is not lost yet, though. If policymakers incorporate climate change into their plans for the lynx, the cats can survive, the scientists say. If climate change were considered in the planning of reintroduction efforts, those efforts could result in there being as many as 900 Iberian lynx by 2090.

The establishment of wildlife corridors along climate pathways might also help. The research team cautions, however, that the immediate nature of the threat, high costs of the corridor creation, and the fact that translocating lynx is technically feasible means that it’s probably easier to just move the cats rather than try to get them to move on their own through a corridor.

“The risk of extinction faced by Iberian lynx within the next 50 years is high,” the researchers write. But with good planning, extinction of the lynx might still be avoided.


Images Credit: Hector Garrido, CSIC Andalusia Audiovisual Bank, via EurekAlert

How Might Climate Change Affect Asian Elephants?

elephantsThis morning’s news brought word of a study in Nature Climate Change that predicts devastating global species losses as a result of climate change. The analysis found that some 57 percent of plants and 34 percent of animals would lose more than half of their range by the 2080s if nothing is done to stem the tide of rising greenhouse gases.

“This broader issue of potential range loss in widespread species is a serious concern as even small declines in these species can significantly disrupt ecosystems,” the study’s lead author, Rachel Warren of the University of East Anglia in England, said in a statement.

But it might be easy for many people to ignore something as nebulous as “plants” or “animals” or “ecosystems.” After all, maybe your favorite one won’t be affected. So lets look at another recent study, one of Asian elephants in Myanmar (Burma) that was just published online in Ecology.

Researchers from the United Kingdom and Germany analyzed longevity data from 1,024 semi-captive elephants that were born between 1948 and 1999. These elephants are used in places like the timber industry in Myanmar. They work during the day but forage for food on their own at night, and they breed at will. They have many similarities to fully wild elephants but are easier to study.

This dataset included not just information on how long each elephant lived and how they died, but also about the environmental conditions during their lifespans — specifically, temperatures and rainfall. That let the scientists see how the elephants survived during hot versus cold spells, or during rainy seasons and droughts.

Both temperature and rainfall influenced the survival of elephants over the time of the study. Heat was especially bad — most deaths occurred when temperatures were above 24 degrees Celsius (75 degrees Fahrenheit). Very cold times also weren’t good for the elephants, nor was drought.

That is not good news for Asian elephants, which are already dwindling in numbers. Southeast Asia is expected to warm by up to 3 degrees C over the next 30 to 40 years, accompanied by changes to the yearly monsoon season. “Increased extremes in temperature and rainfall (both within a year and between years) may therefore lead to significant increases in mortality of Myanmar elephants in the near future,” the researchers write.

There has been some debate in the scientific community about whether long-lived creatures will be affected all that much by climate change, and whether species in tropical regions, already adapted for heat, will do as badly under warming conditions. This study, of long-lived elephants living in tropical Myanmar, puts holes in both those theories. “Despite living in a highly seasonal environment, our results indicate that modest deviations from optimal conditions have effects on Asian elephant survival,” the researchers write. Elephant survival under even modest climate changes, therefore, will be a challenge.

Image of elephants in Myanmar courtesy of flickr user Mandala Travel

Bad News For Animals That Live In The Subnivium

voleYou’ve probably never heard of the “subnivium.” That’s because it’s a term that scientists just made up (they do that). The group of ecologists and biologists, led by Jonathan Pauli of the University of Wisconsin, say in an article recently published in Frontiers in Ecology and the Environment that the subnivium is the seasonal refuge that occurs below the snow where there’s environmental stability. It’s cold there, with temperatures near freezing, but this region serves as a retreat from the harsh, sometimes changeable environmental conditions above.

A healthy subnivium contributes to a healthy ecosystem. Insulated soil lets microbes and fungi breathe and proliferate and process organic matter. Plants benefit from increased carbon dioxide and warmer temperatures, especially during late winter and early spring. Many animals — a list that includes invertebrates, amphibians, reptiles, birds, and small mammals — will use the region to hide out during the winter, feeding off each other or any vegetation they can find. There are whole ecosystems below the snow.

But warming conditions have led to many changes in the patterns of snow in the Northern Hemisphere (that’s where most of the world’s snow is found): The month of maximum snow cover has shifted from February to January. The spring melt is about two weeks earlier than it was decades ago. The extent of land covered in snow in the winter has been shrinking. In many places, the amount of time when snow is more likely than rain has decreased by more than one and a half months. Snow depths are decreasing, as are snow packs. The list goes on and on.

“Snow cover is becoming shorter, thinner and less predictable,” Pauli said in a statement. “We’re seeing a trend. The subnivium is in retreat.”

With all these changes, the stability that the subnivium provides is therefore disappearing. What does that mean for the ecosystems that thrive there? One worry is that organisms, such as plants, that are exposed to cycles of freezing and thawing could experience tissue damage. Others, like voles or insects, that lose the layer of snow that hides them may be subject to predation by birds or other critters.

“Decay of the subnivium will affect species differently, but be especially consequential for those that lack the plasticity to cope with the loss of the subnivium or that possess insufficient dispersal power to track the retreating range boundary of the subnivium,” the researchers write. Those that can adapt to the loss of stability or can move to places where there’s still reliable snow cover will do better than others. Adapt or move — those seems to be the only two options for surviving climate change.

Image of vole courtesy of flickr user musubk

Frogs Take Up Residence In Manmade Caves In Portugal

frogSerra de Estrela Natural Park encompasses a section of Portugal’s highest mountains. The largest natural conservation area in that country, the park is full of wildlife. There are wall lizards, otters, wild cats, water moles, and even wolves, to name a few species.

Back in the 1950s, before the park’s boundaries were delineated, several artificial caves were created in the area. These were drainage galleries — small, horizontal tunnels built to push a few meters into the hillsides, often with a small stream of water running through.

In May 2010, according to a study from Portuguese researchers published in the Journal of Subterranean Biology, an unexpected resident was found in the galleries: the Iberian brown frog (Rana iberica). These frogs are often found the the mountains, and also live in other moist habitats, such as ponds and soaked fields and humid meadows. But they’d never been found in caves.

The researchers returned to the galleries the next year, every three months at first, then every month from December 2011 to December 2012. Adult frogs were found throughout the year, in day and in night, on the ground, tucked into crevices, swimming in water, and even climbing up the walls (as in the photo). Usually the frogs were living deeper into the galleries, more than five meters from the entrance where the daylight had dimmed.

The frogs mated throughout the year, then laid their eggs within the caves. The tadpoles hatched there, and the frogs grew up there. It wasn’t necessarily an easy life, however. Tadpoles would sometimes eat frog eggs — a first for this species — and tadpoles themselves were occasionally eaten by fire salamander larvae.

This may be just be a case of a species moving into a newly available habitat, but it might instead be a consequence of changes humans have made to the frogs’ home. “Nearby breeding sites may have disappeared or experienced disturbance,” the scientists hypothesize in their paper. But they also note that this region of the world is expected to experience dramatic climate change in the near future, with changes that include increasing aridity and greater fire activity. By taking up residence underground, the frogs may be smartly fleeing the changing landscape above. It could be a hopeful sign that the world’s wildlife will do its best to survive the changes we are making to their planet.

Image courtesy of Gonçalo M. Rosa, via EurekAlert

Why Climate Change Could Be Bad News For Snowshoe Hares (And Lynx)

hareThe snowshoe hare (Lepus americanus) has mastered the art of camouflage. In warm times, its coat is a muddled brown, easily blending into a background of trees, rocks, and dirt. As the days shorten and the temperatures begin to drop, it sheds its coat and grows a new one of snowy white, perfect for the snowy days sure to follow.

There’s been worry, however, that this well-honed system could fall apart under climate change: If winters get shorter and snowshoe hares don’t change the timing of their molts, they could be left vulnerable to predators, bright white targets on a brown background.

That worry may be well founded, according to a study published today by PNAS. Researchers from the University of Montana in Missoula and the University of Idaho in Moscow found that the timing of molts, both fall and spring, is tied to the length of day, and the snowshoe hares have no ability to change their fall molt and only a little for the spring.

They draw that conclusion from studying 148 snowshoe hares in the wild over three consecutive Montana winters from 2010 to 2012. Those winters were significant because they were very different and included one that was particularly long and another that was very short. That allowed the scientists to see if the hares adapted to changes in winter length.

The molt from brown to white in the fall was fixed, starting at the same time every year and taking 40 days to complete. In spring, there was a little change in 2011, the year of the really long winter, and the hares completed their transition back to brown 16 days later than in the other two years.

But when the researchers extrapolated from these three years to what may happen later this century, as temperatures rise and winters get shorter, they found that the number of days that snow-white hares can be found in brown landscapes would increase by fourfold by the middle of the century and eightfold by its end.

That’s definitely bad news for snowshoe hares, but it may also bode ill for the Canada lynx (Lynx canadensis, not named particularly well since it’s also found in the United States). The ecology of lynx and snowshoe hares is intertwined, as Smithsonian reported a couple years ago:

The northern [Canada and Alaska] lynx population rises and falls according to the snowshoe hare’s boom-and-bust cycle. The hare population grows dramatically when there is plenty of vegetation, then crashes as the food thins out and predators (goshawks, bears, fox, coyotes and other animals besides lynx) become superabundant. The cycle repeats every ten years or so. The other predators can move on to different prey, but of course the lynx, the naturalist Ernest Thompson Seton wrote in 1911, “lives on Rabbits, follows the Rabbits, thinks Rabbits, tastes like Rabbits, increases with them, and on their failure dies of starvation in the unrabbited woods.” Science has borne him out. One study in a remote area of Canada showed that during the peak of the hare cycle, there were 30 lynx per every 40 square miles; at the low point, just three lynx survived.

The boom-and-bust cycle of hares and lynx isn’t quite as dramatic in the animals’ southern range, where forests are patchier and lynx less common. But all lynx are snowshoe hare specialists, and that specialization may put them at risk. If the hares become more vulnerable to climate change, that doesn’t mean that lynx will automatically get more of them. Other predators (the goshawks, bears, fox, coyotes, and other animals mentioned above) could get to them first, leaving fewer for the lynx. And the lynx, because they’re specialists, won’t be able to fill their tummies with anything else, resulting in, ultimately, fewer lynx.

There are at least nine other mammal species that undergo coat changes in winter similar to that of the snowshoe hare, and unless they’re able to adapt their timing, they will face scenarios also similar to the snowshoe hare. The forces of evolution may help out some of these species, though — as the researchers note in PNAS, natural selection should not be discounted.

Image courtesy of flickr user DenaliNPS

If You Like To Eat King Or Snow Crab, Worry About Climate Change

red_king_crabIf you eat crab, there’s a decent chance you’ve had king crab or snow crab — the type they often sell in grocery stores and restaurants as just big red arms — which are brought up from chilly waters in places like the Bering Sea off Alaska. The future for these species is uncertain; as with many tasty critters, they’re overfished and on the decline. But more worryingly, finds a study in PLOS One, the crabs are vulnerable to climate change.

Researchers from the National Marine Fisheries Service Kodiak Laboratory in Alaska studied two species of crab: the red king crab (the most sought-after kind of king crab) and a snow crab known as the Tanner crab. They raised young crabs for a little over half a year in tanks with sea water at one of three pH levels — 8.0, 7.8, and 7.5 — and then tracked the crabs’ growth.

The scientists were interested in the effects of ocean acidification on the crabs. As we pump more and more carbon dioxide into the atmosphere, the ocean absorbs some of that gas, which causes the water to become more acidic over time. Some areas of the world will be affected more than others, and northern regions are expected to become more acidic than tropical ones. The three different pH levels range from the current state of the water (8.0) to what will exist at the end of the century (7.8) to what could exist in the not-too-distant future (7.5).

Ocean acidification is a particular worry for organisms that rely on calcium carbonate to construct their skeleton or shell, like coral and crabs. If the pH of the water is too acidic, it will be too difficult, too costly for these organisms to turn calcium and carbonate into calcium carbonate to build their bodies.

At the 8.0 pH level, the crabs grew just fine. Some crabs died, but that’s normal. At a pH of 7.8, more crabs died; less than 40 percent of the red king crabs and about half of the Tanner crabs survived to the end of the study period. And at the 7.5 pH level, less than 40 percent of the Tanner crabs lived to the end, and all of the red king crabs died within 95 days. Growth rates were also affected by the acidic waters, with the crabs not growing as well when pH was low.

Given these results, the researchers predict that ocean acidification will cause a serious decline in these species by the end of the century, with red king crabs affected first. Even before then, though, small increases in acidity could affect crab growth. Because smaller crabs are more vulnerable to predators, they’re more likely to get eaten and not survive too long. Their smaller size could affect the predators that eat them (they won’t be as satiated by their crab meals), and that’s just the beginning of a host of changes that could sweep through the food web, affecting species that may not be directly impacted by water pH.

Crabs and other species may be able to adapt to more acidic waters. There are some cousins to the red king and Tanner crabs that live in deep places with lower pH, which shows that such adaptation is possible. But greater acidity at the surface could also open up these waters to the deep-sea species, resulting in a crab competition. What this means for the species we love to eat, well, only time will tell.

Image of red king crab courtesy of The Children’s Museum of Indianapolis, via wikimedia commons

Polar Bears Survive Disappearance Of Sea Ice By Moving To Land


Polar bears live an incredibly specialized existence in the Arctic. Though born on land, they prefer to live on sea ice, from which they can hunt the seals that make up the majority of their diet. But with sea ice disappearing, there’s been well-founded worry about what will happen to the polar bear (Ursus maritimus).

It might be easy to assume that the bears will give up their icy lives and move to land. And a study of the polar bears of the Western Hudson Bay, published by the Journal of Animal Ecology, has found that the bears do just that — moving onto shore when the sea ice retreats and returning to the ice when it grows again later in the year. By tracking more than 100 female polar bears for over a decade, the researchers found that the bears’ migration could be timed to the movements of the sea ice.

But that time between the sea ice retreat and return has been getting longer and longer as the Arctic warms, with the result that the bears are spending more and more time on land.

“The data suggest that in recent years, polar bears are arriving on shore earlier in the summer and leaving later in the autumn. These are precisely the kind of changes one would expect to see as a result of a warming climate and may help explain some other studies that are showing declines in body condition and cub production,” the study’s lead author, Seth Cherry of the University of Alberta in Canada, said in a statement.

The problem is that on land the bears don’t hunt, or at least not enough to matter; they live off their stores of fat. Subadult bears, like the one above, are particularly vulnerable because, due to their smaller size, they have less fat to rely on. And their survival rate has been dropping. This might also explain the trend in decreasing litter size. Females don’t have enough fat to both survive the long summer and give birth to, and maintain, multiple cubs.

Which all makes me wonder: What happens when the summer gets too long for even the fattest bears to survive?

Image copyright Andrew Derocher, Univeristy of Alberta, via EurekAlert