The Endangered Cheetah and Genetic Bottlenecks

by sciencesays

The addition of the cheetah to the endangered species list last week was a sad blow to wildlife conservation groups that have fought hard to protect the species. However, in the past, the cheetah had been seen as a conservation success. What happened to drive the cheetah back to the brink?

Nothing.

 

The cheetahs didn’t need a push this time - the truth is, the species had never really recovered. Using outdated metrics, the cheetahs’ population had increased to the number that we believed was necessary for a chance at survival.

Unfortunately, the damage had already been done - the new cheetahs were descended from such a small population that there was little genetic diversity in this new population. To give you an idea how severely inbred the species has become, a skin graft from any cheetah can be put onto any other and will be accepted. Humans, on the other hand, have so much genetic diversity that there are probably members of your own family who would be too different for skin grafts to take.

When a population gets as small as the cheetah’s did in the past, there is no turning back. You can breed more animals, but the genes are lost forever. We can import genetically diverse members of another group, but since there are only ~15 cheetahs left in Asia, that’s not an option. Otherwise, it’s time to sit back and wait for mutation and evolution to take charge. This is a precarious position, though - the diversity of genes is what allows a species to adapt and to withstand external pressures, like famine, drought and disease - the lucky ones survive the hard times and the species gets stronger.

If genetic diversity gets as low as the cheetah’s, the whole species becomes vulnerable. Additionally, inbreeding will further damage the remaining animals and make survival ever harder for future generations, an effect known as inbreeding depression.

This indicates a weak and vulnerable population, as well as substantial inbreeding. Nothing terrible had to the cheetahs, this time - this was just a return to the effective population size. It was inevitable. 

photo by James Temple

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5 Things the Environment Can Be Thankful For

by sciencesays

It’s been a hard year to be an environmentalist, but there are definitely still some things to be thankful for in 2008, especially in the last half of the year. 

1. Polar Bears listed as an Endangered Species

I know, I know - animals becoming endangered isn’t usually a good thing, but in this case, the polar bears were already in trouble and the government was just refusing to acknowledge. It took a multi-year lawsuit by Greenpeace to force the federal government’s hand and the polar bear was finally listed for protection. 

2. High Gas Prices

Another thing that seems counterintuitive at first glance, rising gas prices are going to be great for the environment. While the crisis this fall hit everyone in the pocket, I hope that, long-term, this will be seen as a turning point for the energy industry. As long as gas prices were creeping slowly upwards, year after year, people were going to accept the change with a grumble instead of demanding change. The prices skyrocketing well over $4 dollars a gallon this year shocked the world, and helped elect Barack Obama, a candidate who has committed to an alternative energy revolution in America. If it happens, this will be a fantastic win for air-quality and pollution, and a major step towards combating global warming.

3. The Announcement & Rejection of Offshore Drilling

John McCain and George Bush made a tag-team attempt at repealing the American ban on offshore drilling this summer in a bid to capitalize on gas prices to help John McCain win the Presidential election. Immediately, cash-strapped Americans, oil companies, and politicians in coastal states who were envious of tax revenues in oil-rich states, jumped on the issue, practically salivating at the pools of money they imagined. 

Fortunately, over time this came to be seen as the shameless political ploy that it was, and the association with George W. Bush only hurt McCain in the long run. Following Obama’s promise of $150 billion dollars to jump-start the alternative energy industry, the plan seems to have fallen on its face.

We’re all lucky it came up with it did, and was dragged down by McCain and Bush’s disastrous fall. 

4. The Rise of the Electric Car

Even before gas went completely out of control, people were starting to think proactively about getting more alternative-energy cars on the road. The Tesla Roadster debuted this spring and blew conventional prejudices about electric cars out of the water, and it seemed like everyone began thinking about luxury electric in a new way. Throw in the gas crisis, and major automakers around the world began to throw their weight behind new kinds of cars as SUV and truck sales ground to a halt. This led to the announcement of the Chevy Volt, the first plug-in hybrid, and a rush of electric auto development. Australia and the city of San Francisco both announced plans to build comprehensive recharging networks, and the day of the internal-combustion engine seems to be coming to a close.

5. The Economic Crisis

This one might be controversial, but hear me out: as long as the old ways were working, at least well enough for some people to get rich, nothing was really going to change. GM thought about an electric car before: they gave up. Jimmy Carter put solar panels on the White House 30 years ago: Reagan tore them down. We had a gas crisis in the 1970s: nothing really changed. 

While this recession is going to be hard, we also don’t have much left to lose. That’s going to make it easier to change. It undermines industry’s favorite excuse for staying the same, and puts Obama’s government in the position to say “Your way has failed” and force the country to make a change. 

It’s hard to imagine relying the same way on oil from the Middle East. It’s hard to imagine denying global warming any longer. It’s hard to imagine us going back to the same old way, now that we’ve seen just how bad it can get.

I’m thankful that we seem to be making these steps, even if it took a disastrous year to get there.

Super special bonus: NO MORE BUSH!

The Daily Green recently published list of the worst environmental Presidents in American history. Guess which guy was number one? There’s no way that things won’t get better next year. Bush loved oil companies, was willingly courted and corrupted by big-business, didn’t believe in global warming for most of his presidency, denied its human causes once he did, and was an outright enemy of environmental protections and the Endangered Species Act. Kicking him and his party out of office was easily the biggest step that we could have taken this year, and the door is open for great changes in 2009. 

Happy Thanksgiving, everybody! Hope you’re all enjoying your holiday.

gas prices by glenn.batuyong, oil rig by PhillipC, Tesla roadster by Mike Weston, Graph by iburiedpaul, Bush by ImageEditor

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Why Science is Essential to the Endangered Species Act

by sciencesays

As promised, President Bush is trying to ram through a sweeping change to the Endangered Species Act by Friday that would remove scientific review and completely undermine the effectiveness of the act.

Scientific review, the effective core of the Act, would be removed:

The rules eliminate the input of federal wildlife scientists in some endangered species cases, allowing the federal agency in charge of building, authorizing or funding a project to determine for itself it is likely to harm endangered wildlife and plants.

Current regulations require wildlife biologists to sign off on these decisions before a project can go forward, at times modifying the design to better protect species.

Self-regulation - isn’t that an oxymoron?

This isn’t just something that the greenies have saddled the poor government: peer-review is the basis of credibility in modern science, and an utterly essential part of the ESA.

This isn’t just because the “greenies don’t trust the government” - it’s because it’s widely accepted in the scientific community that Everyone Makes Mistakes. Even if the government could be trusted to look out for the best interest of the environment (and they can’t), it’s simply foolish to trust decisions this important to one person or one regulatory body, especially one that has a vested interest in promoting business.

That said, the concept of self-regulation is a fraud: the history of American business has proven that, in a free-market, corporations look out solely for their bottom-line.  Some have argued that they’re neglecting the long-term value of environmental responsibility, and while that’s true, the record of corporate negligence and waste, regulatory laziness or corruption, and subsequent activism and clean-up, speaks for itself.  The majority of businesses act in the best financial interest of their majority stakeholders most of the time - environmental values and responsibility don’t enter into the equation.

The inclusion of scientists into the process is the only thing that gives the Endangered Species Act the power to intervene in the decline of a species, in the face of the government, business and industry. If you looked over the history of the Act, I’m sure you’d find hundreds of instances where both business and the federal agencies didn’t like a particular finding, but the credibility of the scientific method and its inclusion in the process has usually won. The Bush Administration, Republicans and their big-business campaign donors hate that.

This basis in science is what gives the Endangered Species Act its authority and what has made it capable of saving species that stood in the way of business. Removing that provision neuters the act and corrupts the process. If this rule change is allowed to pass, the Endangered Species Act will be dead.

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More polar bears becoming cannibals

by sciencesays

CNN released a new video today documenting the plight of polar bears, this time in Alaska past the ege of the Arctic circle.

By this time of year, polar bears have been without food for 4 or 5 months, but can’t get out to hunt the fatty seals that sustain them through the cold winter months because the sea ice has been slow to arrive. The polar bears have been fasting for so long that they are currently losing roughly 2 pounds every day.

Researchers in the arctic blame this on global warming, which they profess to have seen just within their lifetimes. The large flows of sea ice arrive later every year, and last for shorter periods than even a decade or two before.

The researchers have no doubts that the polar bear deserved to be listed as threatened this year. For evidence, they cite the emergence of cannibalism, which we discussed here before at ScienceSays. They say this is not scavenging or opportunism, which had been seen on rare occasions in the past. Instead, researchers have observed “large adult males stalking and killing other bears, actual stalking, killing and consuming other animals” which had never seen before last year, and has continued during this hard summer season.

The scientists conduct regular monitoring of the bears’ weight as an indicator of their general health, and the average bodyweight has fallen nearly 25% in the last 20 years, particularly among females, for whom weight is a bigger concern (as a major factor in their fertility.)

Whatever your opinion on the causes of global warming, the scientists who’ve spent decades monitoring polar bears in the arctic can confirm that the ice is melting, and that the polar bears are at risk. Interspecific predation of this nature, also known as cannibalism, is a terrible sign of desperation in a mammal population, and it will be painful to watch the future of the polar bear unfold if drastic actions are not taken soon.

photo from NOAA

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Back to the Real World

by sciencesays

Barack Obama is going to be the next president, but as some predicted, that doesn’t mean things are going to get easy:

Even as we begin to learn the full scope of Bush’s attacks on the environment, we find out that Dubya is looking to force through rule changes before he leaves office that would gut the Endangered Species Act and protections against pollution. Obama has said he would reverse many of these as soon as he takes office, but will it be in time?

Meanwhile, the Supreme Court has ruled that the Navy’s interests override the health and welfare of whales and dolphins, even as more evidence comes to light about the damaging effect of human-created noise on marine mammals.

America, we’ve got a long way to go.

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