Thursday, September 23, 2010

Lizard Extinction: How Severe?


In many newspaper or magazine articles, information is often lost or changed in order to generate more interest. In a recent article, the Time Magazine presented the results of a scientific study, although there was some discrepancy between facts and the overall presentation of the issue. The study, published in Science of May 2010, researched the effects that climate change is having on the worldwide lizard population, and determined the local and global extinction rates of many lizard species.

The team, led by Barry Sinervo, resurveyed 48 species of lizards at 200 sites in Mexico between 2006 and 2008, previously surveyed between 1975 and 1995. It was determined that approximately 12% of the measured species was extinct by 2009 (Sinervo et al. 2010). These results are one of the areas where the information of the magazine article and journal coincide. However, a small difference in the magazine article appears when the author reports that the only difference between the surveyed years is the change in temperature (Lemonick 2010). While this may well be true, the journal article did not report it to any degree. The magazine seems to be implying that the researchers determined this difference; when in fact, according to the journal, they did not.

Putting this relatively small difference aside, one can notice a larger and more meaningful similarity. The magazine accurately reported the theory presented in the study that explains the reason behind the extinctions. The authors of both articles discussed that the lizards have less time to reproduce because they now spend more time looking for shade. Thus, the increasingly global temperature is affecting reproduction rates, which in turn affect population growth rates and increase the risk of extinction (Lemonick 2010, Sinervo et al. 2010).

Each article used different approaches in getting this point across, each equally effective for its targeted audience. First, the journal article used more scientifically appropriate vocabulary, such as the critical thermal maximum, which is the maximum temperature that lizards can endure before there is the risk of overheating. Another term frequently used is the hours of restriction, meaning there are more hours spent in or looking for shaded areas, rather than foraging or reproducing. In addition, the scientists conducted experiments in which they measured the hours of restriction in similar geographical regions in which the extinction rates are both high and low in lizard species. They determined that the hours of restriction were much higher, meaning more time was spent in shaded areas, where the risk of extinction is high, as was expected (Sinervo et al. 2010). Using this and many more statistical experiments, the scientists are able to be very convincing in their claims towards their audience (primarily other scientists and academia).

On the contrary, Time magazine did not use any such tests to support their claim that lizards have less time to reproduce. Instead, at the end of their explanation the author gives a quote from one of the co-authors of the study, which solidified the information (Lemonick 2010). When a magazine, read by people with varying intellect, presents information about a study, the presence of statistics is impractical because many people will be unable to understand it. Usually, a quote from a dignified academia is all that is required for average people to confirm the statements, especially from one that is a part of the research presented.

However, it is important to rethink the statements supposedly made by researchers. For example, the magazine article states, “In the southern hemisphere, where a greater ocean-to-land ratio has kept temperature increases relatively moderate so far, lizards have largely escaped extinction, according to Bauer [a co-author of the study]” (Lemonick 2010). At first this quote seems to give hope for some lizard species and seems to be reputable, however upon closer cross-examination with the journal, there is absolutely no evidence that is given or hinted at towards this claim. In fact, it gives quite the opposite in stating that there have been reported local extinctions in South America, Africa, and Australia (Sinervo et al. 2010).

In response to the global extinctions, the magazine article states, “The results, appearing in the May 14 issue of Science, are dramatic: populations of lizards have been lost on five continents over the past few decades” (Lemonick 2010). The impression that this quote gives is that all of the populations on five continents have been lost, since it mentioned the results are dramatic. Again, when compared to the original study in the journal, there are significant differences. While the journal does state lizard extinctions on five continents (North and South America, Europe, Africa, and Australia), they are only referring to local extinctions, not the complete continent population. The study’s model used local extinctions to confirm that extinctions are spanning tropical, temperate, rainforest, and desert habitats (Sinervo et al. 2010).

Finally, the magazine and journal differ by the expected percentages of extinction for 2050 and 2080. According to the Time magazine, “scientists predict that by 2080 nearly 40% of all lizard populations and 20% of lizard species could vanish” (Lemonick 2010). In comparison to the journal, this is not completely correct. The values given in this quote correspond to the projected values for the equatorial extinctions, meaning only the lizard species that live around the equator (Sinervo et al. 2010). These are obviously higher because the temperature is significantly warmer there. In order to gain a better understanding of the future of the lizard population, one must look at the values for the global average. According to Sinervo et al. (2010), the expected global average for extinctions will increase to 16% by 2050 and 30% by 2080, from the 4% extinction rate reported in 2009.

Clearly, there can be a lot of variation between original journal articles and news or magazine articles. While in this case, the magazine did keep the basic facts of the journal intact, it was not immune to the distortion of facts to gain reader interest. The magazine seemed to give an overall impression that worldwide lizard extinction is fast approaching. While the extinction of lizard species, and any species for that matter, is terrible and could have many repercussions on other species, the journal gives the impression that it is merely another problem associated with climate change. While these two articles contained both similarities and differences in their presentation of facts, not all news articles will. It is important to remember the reason an article is in the news, to gain more reader interest.

By: Megan Nelson

Word Count: 1081

Works Cited

Lemonick, M. D. (2010, May 13). Study: Global Warming is Driving Lizards to Extinction. Time. Retrieved from http://www.time.com/time/health/article/0,8599,1989115,00.html

Sinervo, B., Méndez-de-la Cruz, F., Miles, D. B., Heulin, B., Bastiaans, E., Villagrán-Santa Cruz, M., ... Sites, J. W. Jr. (2010, May 14). Erosion of Lizard Diversity by Climate Change and Altered Thermal Niches. Science, 328 (5980), 894-899. doi: 10.1126/science.1184695 Retrieved from http://www.sciencemag.org/cgi/content/full/328/5980/894

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