From CELL PRESS, a claim that anyone who has ever dealt with fast growing bamboo would have a very hard time believing – see details why at the end of this story.
Climate change may slowly starve bamboo lemurs
Madagascar’s Cat-sized greater bamboo lemurs are considered one of the most endangered primate species on Earth. They almost exclusively eat a single species of bamboo, including the woody trunk, known as culm. But they prefer the more nutritious and tender bamboo shoots and use their specialized teeth to gnaw on culm only when necessary, during the dry season.
Now, reporting in Current Biology on October 26, researchers provide evidence to suggest that as Earth’s climate changes, bamboo lemurs will gradually be forced to eat culm for longer periods. Ultimately, they suggest that, based on an analysis of anatomical, behavioral, paleontological, and climate data, the lemurs could slowly starve.
“For extreme feeding specialists like the greater bamboo lemur, climate change can be a stealthy killer,” says Patricia Wright at Stony Brook University, one of the authors. “Making the lemurs rely on a suboptimal part of their food for just a bit longer may be enough to tip the balance from existence to extinction.”
Wright and her colleagues from Finland and Australia first showed that the greater bamboo lemurs are equipped with highly complex and specialized teeth, just like giant pandas — the only other mammal capable of feeding on culm. These teeth make it possible for them to consume and survive on woody culm for parts of the year.
To find out more about the greater bamboo lemurs’ feeding habits, the researchers spent hours watching them in their natural habitat in Madagascar’s Ranomafana National Park over a period of 18 months. They collected more than 2,000 feeding observations in total. Those data showed that the lemurs spend 95 percent of their feeding time eating a single species of woody bamboo. But they only eat the culm from August to November, when dry conditions make tender shoots unavailable.
An analysis of the greater bamboo lemur’s current distribution on the island of Madagascar compared to its distribution in the past, as inferred from fossils, suggests that the lemurs used to live over a broader range. The bamboo lemurs remain only in parts of the island where the dry season is relatively short. In other words, it appears that a short dry season has been crucial to the survival of greater bamboo lemurs in the past.
But the researchers have bad news: climate models suggest that the areas where the lemurs currently are found are likely to experience longer and longer dry seasons in the future. As the lemurs are left with only culm to eat for longer periods, it could put their survival at risk.
The findings may have implications for understanding the fate of bamboo-feeding giant pandas, too, the researchers say. Giant pandas are threatened by deforestation and changes in the distribution of bamboo. But the new data suggest that a changing climate may also endanger bamboo feeders in a more subtle way, by affecting the seasonal availability of preferred and more nutritious bamboo parts. Other animals with highly specialized diets may prove similarly vulnerable.
“By studying specialists like the greater bamboo lemur, we can identify the different ways that climate change can cause extinction,” says author Jukka Jernvall at University of Helsinki. “And if we do not study these endangered species now, they may go extinct before we know all the reasons why, and we’ll be less able to protect what remains.”
The researchers say they now hope that this expanded understanding of the greater bamboo lemurs, together with climate predictions, can be applied to building bamboo corridors, with the goal of connecting isolated lemur populations and expanding their habitats.
This study was supported by the Academy of Finland, Stony Brook University, Marie Curie Actions of the European Union, and the Kone Foundation.
Current Biology, Eronen and Zohdy et al.: “Feeding Ecology and Morphology Make a Bamboo Specialist Vulnerable to Climate Change” http://www.cell.com/current-biology/fulltext/S0960-9822(17)31248-4
Here’s why I think this study is absolute junk:
1. They rely exclusively on climate model projections, and we all know how highly variable those can be with output in the future
2. They seem to have this idea dry seasons In Madagascar will get drier and longer, but we’ve seen climate models produce both outcomes; wetter in the future and drier in the future. Take California for example, we have claims of wetter and drier based on model outcomes. It seems to me they didn’t consider both, focusing only on drier because that’s the one that matches their goal to show bamboo lemurs would be affected.
3. They didn’t actually test any of the preferred bamboo growth and hardiness against the climate models, but instead relied solely on feeding observations of bamboo lemurs.
4. They assume climate change is the only factor, but it seems that other factors have been contributing to the extinction for a long time, even before climate change became a popular boogeyman for extinction. Scientists once believed that it was extinct, but a remnant population was discovered in 1986.See: http://savingspecies.org/projects/past-projects/saving-species-the-bamboo-lemur From that article/proposal:
Prior to the 1970s, greater bamboo lemurs were only known from two sites and following another decade of little research and much forest destruction, it was suspected that P. simus might be extinct.
Feared extinct until its rediscovery in 1986, the current status of P. simus is desperate. Surveys of south- and central eastern Madagascar over the past twenty years have found fewer than 75 individuals (with a recent total count of 60). Compared to their historic distribution, the current range is approximately 1 to 4 % of its former range most of which is not suitable habitat due to their dietary specialization on bamboo and microhabitat preferences. In addition, various localities containing critically low population numbers have no official protection and exist in severely degraded landscapes.
Hmmm, it seems “forest destruction” is the bigger threat to the lemurs in the present than climate change could be in the future, and has been for a long time. That’s why in the proposal linked above, they want to purchase the land
5. With the discussion about the bamboo-feeding giant pandas thrown into the press release, the well know heartstring tugging icon of the WWF, it seems they are appealing to human sensitivities, just like the WWF does. From the paper, there’s that deforestation issue again:
In China, compounded with human caused deforestation, changing climate has been suggested to affect bamboo distribution in the 21st century, thereby causing food shortage for the giant panda . Our data suggest that rapidly changing climate may also endanger bamboo feeders in a subtle way by affecting seasonal availability of preferred bamboo parts, and the giant panda may be similarly vulnerable .
Deforestation leads to loss of evapotranspiration by the trees and plants of the tropical forest, and that leads to lowered rainfall in the region. Climate change has nothing to do with that effect. See https://www.livescience.com/23017-deforestation-reduces-rainfall.html
Perhaps this PR is just a prelude to a “save the bamboo lemur” organization? It looks like desperation in the form of “we’ll mention climate change and people will send money, yeah, that’s the ticket!”.