The Last Siberian Tigers

by sciencesays

siberiantiger

Another day brings another fascinating report from BBC Earth, but this one has absolutely gut-wrenching news about the future of Siberian tigers:

Researchers have estimated that the effective population size of the Amur(Siberian) tiger has now dropped to just 35.

You may remember that we talked about effective population size in regards to genetic bottlenecks and the endangered cheetah a few months ago - the effective population size of a population is the theoretical number of individuals that it would take to represent all the genetic possibilities left in a species.

This is used as an indicator of the genetic diversity and health of a population, and is crucial in determining the vulnerability of a population, since groups of animals that have very similar genes are susceptible to catastrophic disease outbreaks and the damages of inbreeding.

In the case of the Amur tiger, this is readily apparent - while it would take just 35 tigers to represent the genes left in the population, there are approximately 500 tigers left in the wild, with nearly that many still living in zoos.

That’s shocking - even in other endangered species, the ratio is often about 1 to 10. The fact that the Siberian tiger’s genetic diversity has dropped below that is a sobering sign that these tigers are extremely vulnerable, and that their future is very bleak.

However, it gets even worse: the breeding population left in the wild seems to be naturally split into two distinct geographic regions, meaning that there is an even smaller number of genes being shared.

“In actuality, it seems that Amur tigers are residing in two, fairly independent populations on either side of the development corridor between Vladivostok and Ussurisk, further lowering the effective size for each from 26 to 28 for Sikhote-Alin and 2.8 to 11 for Southwest Primorye.”

If action is not taken, and quickly, it is hard to imagine that this population will be able to remain stable for very long, and is a tragic reminder of the lasting impacts of overhunting and environmental damage.

Photo by ucumari
Source: BBC

{ 0 comments }

Sounds like a tabloid headinanttakeoverg, doesn’t it?

Researchers have found a “mega-colony” of Argentine ants that spans thousands of miles across multiple continents.

So far, the little bastards have claimed western Japan, the Europeans side of the Mediterranean (yes, the whole thing) and 530 miles of prime California coastline!

“The enormous extent of this population is paralleled only by human society” the researchers write in the journal Insect Sociaux, in which they report their findings.

So…the gauntlet has been thrown down, and they’ve grabbed all the real estate.

The original article comes from the BBC, and is a must-read.

Photo by myrmician

{ 2 comments }

Jen Angel put an awesome article up on Alternet this December about 10 things that are scientifically-proven to make you happy. I don’t usually cover lifestyle stuff, but this is too good to pass up.

Her list includes: 

1. Savor Everyday Moments

2. Avoid Comparisons

3. Put Money Low on the List

4. Have Meaningful Goals

5. Take Initiative at Work

6. Make Friends, Treasure Family

7. Smile Even When You Don’t Feel Like It

8. Say Thank You Like You Mean It

9. Get Out and Exercise

10. Give It Away, Give It Away Now

 

You’ll have to go to the article to find out the scientific basis for each, but it’s a very cool look at the way our attitudes shape our lives and our health. 

photo by Kansir

{ 1 comment }

It’s that time of year when everyone starts making lists of their goals for 2009 - but what can we do better for the environment this year?

Start the Switch to Renewable Energy

Offshore drilling just can’t happen - it would be devastating to the continental shelf, endanger coastal environments with inevitable contamination, and worse still, it’d maintain our self-destructive dependence on fossil fuels. Foreign oil is a political and economic problem, but carbon emissions doom us all. 

Cut Greenhouse Gas Emissions - Fast!

The ozone hole is expanding, global temperatures are rising, air quality is getting worse every year, and the oceans are acidifying faster than we ever imagined - need I say more? We’re fundamentally altering our environment with the fuels we burn to support modern life, and we’re literally choking ourselves to death - the planet will be fine, but we will be in big, big trouble. I don’t know about you, but   a planet of sweaty, sunburned asthmatics scooping jellyfish out of acid oceans doesn’t sound like much fun to me.

Staff the EPA with Scientists

This one seems like a no-brainer, but 8 years later we’ve realized that it’s not so obvious to everyone *cough*Bush*cough*. The decisions our government makes about environmental issues need to be decided by science, using the best research available at the time. There’s no doubt that there will be “inconvenient truths” - what we need to do for our  survival might not be best for business in the short-term, but we don’t really have a choice: modern business is fickle and focused on microscopic periods of time. We need a long-term perspective to plan for out future.

Fix the Endangered Species Act

We knew that Bush was going to gut endangered species protections  - you could see it coming a mile away. Still, if Obama doesn’t act fast to undo these changes, we might as well throw the Act out altogether. There’s no sense listing Endangered Species if we don’t have strong laws to protect them. Asking developers if their projects is safe is like asking criminals if they belong in jail: the truth is not in their self-interest. Objective observers and scientific review are the only way to get effective, trustworthy species management.

Restore the US Global Environmental Leadership

Maybe the ship has sailed on this, but I still think the United States can make a massive impact on global attitudes. Europe’s decades ahead on wind power, but they haven’t formed a unified front. Japan led the way on emissions reduction, but treat species’ protections like a joke. Australia is at the forefront of Endanagered Species management, but their minding industry is a blight. The United States, for better or worse, is still a global tastemaker - we fired up the environmental revolution in the 70’s, but also taught the world to covet materialism, corporate-business, and a carbon-powered car culture. Barack Obama has a stab to start a new trend towards clean energy and away from waste - if he can make it economical in the states, it will be fashionable everywhere. 

It seems like we could spend years undoing the damage Bush has done, and three of these goals could be seen as cleaning up his mess. However, we have to be reasonable, and we have to start somewhere. If we can, as a culture, start to make these changes, the world will look a lot better in 2009.

photo by Wolfiewolf

{ 0 comments }

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

{ 1 comment }