The plight of the Amur tiger: Teaching food chains and energy losses
Last week saw the International Tiger Conservation Forum being held in St Petersburg, Russia where high-profile representatives from 13 countries met to pledge to help save this engendered species from extinction.
There are currently only around 3000 tigers in the wild, 400-500 of these are the Siberian or Amur tiger whose habitat ranges from Eastern Russia into northern China and Korea.
Several ecologists have studied the plight of this particular tiger and it seems that a major reason for its decline in numbers is due to a lack of prey. The boar, Siberian stag and deer that the tiger feed on are being driven from the habitat because of deforestation to make room for farmland or the felling of the valuable cedar tree.
A study by Chris Carbone of the Institute of Zoology in London examined data on the effects of a decrease in prey for 11 different carnivores and concluded that fewer prey always results in fewer predators but for large carnivores like the Amur tiger the effect is 5 times as great.
I thought that explaining the reasons behind the plight of the Amur tigers would be a good context when teaching about food chains to KS2 and 3 and pyramids of number and biomass to KS4 students.
You could start of by telling the students about the Amur tiger and why it is so close to extinction unless something is done. Make sure you show a photo of the tiger in its snowy habitat (similar to what you may be experiencing at the moment!).
KS2/3 students could be shown a food chain of tree –> deer –> tiger and be asked what the effect of deforestation will have on the tiger and why. They could then take roles of delegates at the forum and suggest what could be done about the problem. Current conservation programmes in Russia include stopping logging in certain areas and increasing the populations of prey animals (see weblink below).
KS4 students could be asked why even a small decrease in the numbers of herbivores in the forests will affect the numbers of tigers by applying what they know about energy losses along a food chain.
Tigers are massive carnivores that need to eat a lot of meat to stay alive – at least 9kg a day but they can easily consume 50kg in one meal. They have to eat this much because meat is a low energy food but they need a lot of energy – hunting and thermoregulation is such a cold climate requires calories. The deer also expended energy during its life so only around 1% of the energy that the deer received from the plants it ate will be passed onto the tiger. If you compare this to other smaller carnivores that live in the same habitat such as foxes and badgers they are not endangered because they need less energy.
They could then go on to learn about pyramids of number and biomass with an understanding of how these are constructed and what happens to them and why if a food chain is disrupted.
Website for the tiger summit
Outline of the study carried out by Chris Carbone
Information on how prey numbers in Russia are being increased