The World Conservation Union (The IUCN) has just released it ‘red list’ for 2006 with the headline:
“The number of known threatened species reaches 16,119. The ranks of those facing extinction are joined by familiar species like the polar bear, hippopotamus and desert gazelles; together with ocean sharks, freshwater fish and Mediterranean flowers. Positive action has helped the white-tailed eagle and offers a glimmer of hope to Indian vultures.”
Several species that where listed as ‘vulnerable’ in the IUCN’s 1996 assessement are now listed as extinct, click here.
According to BBC News Online:
“Polar bears are listed as Vulnerable to Extinction based on forecasts that their population will decline by 50% to 100% over the next 50 to 100 years.”
In fact the BBC appears to have used predicted summer sea ice decline as a proxi for polar bear decline. Following is the actual text from the IUCN:
“Polar bears (Ursus maritimus) are set to become one of the most notable casualties of global warming. The impact of climate change is increasingly felt in polar regions, where summer sea ice is expected to decrease by 50-100% over the next 50-100 years. Dependent upon Arctic ice-floes for hunting seals and highly specialized for life in the Arctic marine environment, polar bears are predicted to suffer more than a 30% population decline in the next 45 years. Previously listed by IUCN as a conservation dependent species, the polar bear moves into the threatened categories and has been classified as Vulnerable.”
Now the IUCN may also be using predictions about summer sea ice as a proxi for predicting future polar bear numbers and then just discounting a bit!*
Last time I spent some time looking at polar bear numbers based on the available evidence (click here for the blog post), rather than predictions about how much the planet might warm, I established that:
“There are thought to be about 22,000 polar bears worldwide with about 60 percent in Canada. Most bear populations are thought to be stable or increasing in number. Historically hunting has impacted on population numbers and over-harvesting is still considered the main threat to polar bears.”
———————–
*More information on polar bears and why the IUCN has listed them as vulnerable may be more easily available once the IUCN’s searchable data base is online, apparently from the 4th May which is tomorrow. It would be good then to also have a look at how the northern hairy nosed wombat is fairing. I reckon the single biggest threat to biodiversity in Australia is probably mismanagement of our rangelands with ‘overgrazing’ and ‘vegetation thickening’ the two biggest issues that need tackling. What about a guest post from a reader who owns some country in western Queensland or NSW?
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
The evidence is the science and the forecasts are the politics.
If the polar bears decrease, might the seals increase? Might not warming conditions allow the extension northwards of many species, from microbes to moose. What do the biodiversity experts think?
“I reckon the single biggest threat to biodiversity in Australia is probably mismanagement of our rangelands with ‘overgrazing’ and ‘vegetation thickening’ the two biggest issues that need tackling.”
Would you put these two factors above feral pests (plant and animal), and if so why? Gilbert’s potoroo is one of the most endangered mammals on the planet, thanks largely to introduced predators. Feral pests and land alteration via clearing, changed vegetation regimes and so on tend to work hand in hand in Australia to drive our mammals to the brink – we have the worst record in the world for mammal extinctions.
Libby, You could be right about ferals being a bigger problem than overgrazing and ‘invasive scrub’.
Jennifer and Libby, I think you’ll find ferals (at least grazing ones) are part of overgrazing and invasive scrub
Davey,
Warm winters mean low seal reproduction rate beacause the seals give birth to seal pups on ice floes. This is the case anyway where I live,in Scandinavia
Only 16,119 species threatened with extinction. This is great news. Remember, just a few months ago Professor Myers was telling us 50 species a day were becoming extinct (18,250 pr annum). And the IUCN has a bit more grasp than the professor does.
Note that the listed species, are those that people are largely aware of.
For this reason, most of the species listed are *not *the lower plants and invertebrates, that make up the bulk of threatened species.
The listed species are the ones that scientists are aware of, including invertebrates (see IUCN Red Book). If a species is unknown to science, it’s status cannot be classified by definition.
Shrug, I’m a member of 2 IUCN (Species Survival Comnission) specialist groups.
The conservation problem is there is an enormous bias towards vertebrates (butterflies are the invertebrate exception, but are better thought of as ‘honorary birds’).
When you have most of your management focused on those known species that make up less than 1% of the world’s biodiversity, the risk of distortionary policy is quite palpable. This is already manifested in scientific papers and recovery programmes, where birds and mammals receive most attention. Giving up on the other 99.99% of wildlife because of the uncertainties, doesn’t seem all that optimal.
Mitigating factors for Australia include:
a) it is one of the top-10 species rich countries on the planet. If you have a lot of species, you tend to have a lot of endangered animals in ‘absolute terms’ anyway…
b) A lot of other countries in Europe and Asia have already wiped out (a few centuries ago) a lot of their wildlife. Australia suffers a bit from a survivor-bias.
c) A lot of extinction pressures are a consequence of human decisions made a long time ago (e.g. feral pests) that take a long time for the effects to be felt.
So, is Professor Myers right? Are 50 species a day becoming extinct?(of which one would have to assume more than 49 are “unknown”).
You’ve got to note that the Myer’s figure is a statistical estimate, so the 50 per day already covers a wide range. It could be much lower or (perhaps) higher. IIRC, it is largely based on deforestation rates, which has the twin problem of assuming that such deforestation is ‘permanent’ and invasive species have comparatibly little effect on extinction rates.
The problem with many ‘global’ extinction models is that they assume that vertebrates and invertebrates experience extinction the same way. They don’t.
Invertebrates are much more robust to patch-shrinkage. The entire population of the Giant Tusked Weta, was located in an area of 1/4 ha in the Mercury Islands. Vertebrates typically have much bigger range requirements.
Invertebrates however, are much more vulnerable to patch-separation. Their little legs (or other slimy appendages) aren’t good at crossing big distances.
Thanks Chthoniid for the logical explanation. What I said appears confirmed “…the IUCN has a bit more grasp than the professor does.”