Today has been a good day, my give a pound idea has started to take off and I am extremely grateful to every single person that is taking me closer to achieving my dream!
I’ve been working on my dissertation today, I need to get my survey ready and start collecting responses as soon as possible. The thing taking the most time is trying to find images of animals in pain and showing signs of it that I have permission to use. I’ve had a good response from twitter so am hopeful I should have some pretty soon :). I’ve also found some on flickr under the creative commons license.
Anyways, today I’ve decided to talk about Vultures… Now Vultures came up in one of my exam questions in June, and I believe are a good example of unintended consequences.
The Vulture (Gyps spp.) was once a very common sight across India with 9 species. It now is classed as ‘Critically Endangered’ on the IUCN Redlist, and is Appendix II in CITES. Since the 1990’s there has been a 92% decline in the populations of Vultures (Prakash et al, 2003) at a rate of 16% – 44% per year. This doesn’t sound like a lot, however in 1990 it was estimated that there were between 20million – 40million vultures. Now it is around 10,000 with one species having a mere 400 remaining.
This is not due to humans taking their habitat, or poaching or killing them for sport. In fact its much simplier, and much more sinister. However before I get onto that lets look at the good that Vultues do for us…
Culture and Heritage Vultures are extremely important and indeed respected within local Culture and Tradition. Within the Parsees who are Zoroastrians the theological descendants of ancient fire-worshippers, the elements are sacred and the body is corrupt. Parsees do not bury or cremate their dead, instead they lay out the corpses on towers known as dokhmas for the vultures to eat. In doing so the Parsees profane neither earth nor fire.
Environmental Pollution Vultures as carnivores hold a really important role of stripping the meat from carcasses of dead cattle. This allowed farmers to leave the carcasses where they fell or at local dumps. Now farmers are having to burn or bury the carcasses of fallen cattle or encourage disease by leaving them to rot. This in turn leads to an increase in water borne diseases leading to water born diseases.
Control of the ferral dog population There are around 200million cattle and buffalo in India, yet Hindu Indians tend not to eat beef. Many of these carcasses therefore end up in carcass dumps, a dump in Delhi used to sustain 10,000 vultures, however now vultures are on the decline a similar number of ferral dogs have moved in. And rats are also becoming a problem. This not only means an increase in animal bites, but an increase in zoonotic disease (disease which passes between animals-humans). With the Plague still being carried by rats in the USA, and India already having 80% of the worlds cases of Rabies the role Vultures play in controlling disease is an important one.
Whilst not the best looking avian species, I hope I’ve explained just how important the Vulture is. Now like I said, its a human problem that started in 1973 by a company called Ciba-Geigy (now Novartis) developing a drug called Diclofenac. This drug is a Non-Steroidal Anti-Inflammatory (NSAID) that was developed to treat people, and was adapted for use in cattle in 1980’s. This drug was patented in 1971, this patent expired 17 years later in 1988 which allowed for other manufacturers to produce generic versions of this drug and made it cheap and readily available.
Now because it was so cheap, it became the solution to disease within cattle in India with a lot of use for its pain relieving properties. However this was the downfall of the Vulture. Diclofenac is extremely toxic (poisonous) to Vultures, it causes visceral gout, accumulation of uric acids within tissues and on the surfaces of internal organs. And ultimately leads to renal tube damage and kidney failure.
If we jump to pharmacology quickly, there are four stages when it comes to administering drugs: absorption, distribution, metabolism and excretion. Now it takes time for this process to happen, especially the elimination and until this happens there is drug residue within the body. In the UK this is the reason why there are withdrawl periods before farm animals can enter the food chain after being treated.
Through post mortem testing and carcass examination there was a 13.9% prevelance of residue in carcasses tested (Taggart, 2006). Since this link was identified there has been much political pressure and the manufacture of Diclofenac and use in India has been banned. Education is helping however people are still using Diclofenac simply because they still have leftover stocks of the drug and there is still illegal manufacture. There are safe alternatives available including Meloxicam which has since the ban has decreased by at least half. Predictions indicate that it will be 15 years before the country is safe for Vultures again, in this time however there are significant problems to overcome where Vultures played a role.
There are conservation centers, education programs and captive breeding programs for the Vulture, however is this too little too late? Humans are on the verge of driving another species to extinction through an unintended consequence of our action. Personally I believe that humans have a problem thinking in the short term, this may be influenced by political parties changing every few years at elections, or just a lack of foresight. We cannot predict every outcome of our actions, however we need to consider the consequences before we act.
I hope that this has given some understanding into the potential for the extinction of the vulture, and why it is a human problem. Take a few minutes to consider what unintended consequences your actions have had today.