The Domino Effect of Carnivore Extinction

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(Photo by wildaboutants, http://blog.wildaboutants.com/2010/05/04/oleander-aphids-on-milkweed/)

When you’re playing a game of dominos, it’s easy to see what the outcome will be. When one piece falls, all the other pieces begin to drop too, one by one, as long as they are touching even slightly. Even two pieces that were originally far apart and not touching each other have the ability of affecting one another. A similar pattern has been found in the extinction of carnivores. The smallest links can cause a chain reaction that was completely unexpected.

When one species goes extinct, it causes others to go extinct as well. Sometimes, the species affected are similar to the original species. Other times, they are seriously impacted even if they don’t seem to be directly related.

In fact, even decreasing the size of one population can cause another species’ extinction. This means that random fluctuations in populations could have some pretty scary and serious consequences that none of us have really realized. The consequences of what happens to one species can become the consequences of multiple species.

It is extremely important for us to think about what this all means. Researchers are showing that indirect effects can be just as dangerous for a species as being directly under fire. This is some really surprising information that should change the way we think about extinction, endangered species, and conservation as a whole.

It is apparent that our current focus on conserving a single or specific species is not a good idea. There are so many links across the food chain that are not obvious and may be nearly impossible to predict. While trying to protect one species, both similar and seemingly unrelated species may suddenly go extinct.

We should try to work together to find ways to benefit the entire community. By having a more general outlook we will ultimately be able to save the most species, including the ones that seem immediately in danger. It would really be more bang for our buck, because focusing on one species is not as productive in the long run.

The researchers came to this conclusion by creating four sets of smaller ecosystems, each with three species of wasps, and three species of their prey, aphids. After observing their interactions and testing each ecosystem by taking out different species of wasps and seeing how it affected the aphids, they found that as one wasp population was taken out, others were dying out too.

Observing the interactions and fluctuations in population sizes and the viability of species within these limited “ecosystems” allowed them to predict how a larger number of species would influence each other. They were able to prove that species may go extinct without seemingly being directly “touched”, showing how important it is for us to change our conservation efforts and goals.

Unfortunately in nature, this is not just a game.

 

Reference:

Sanders, D., Sutter, L., Frank van Veen, F. J. (2013). The loss of indirect interactions leads to cascading extinctions of carnivores. Ecology Letters (2013) 16: 664–669. Retrieved from http://onlinelibrary.wiley.com/doi/10.1111/ele.12096/full

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