Annotated Summary – Essay Example

McLaughlin, J., Hellmann, J., Boggs, C., Ehrlich, P. (2002, March). Climate change hastens population extinctions. Proceedings of the National Academy of Sciences, 9, 6070-6074. Retrieved October 19, 2008 from www.stanford.edu/group/CCB/Pubs/paulpdfs/ 2002_mclaughlinetal_climatepopextinction.pdf
The authors looked at two known extinct populations of checkerspot butterfly, and predicted that variability in rainfall contributed to the loss of its habitat, hastening its extinction. This butterfly was dependent on a specific host plant for the survival of its larvae. The authors designed a series of simulations to map actual levels of rainfall against simulated populations of butterflies, and found that the observed populations corresponded to the simulated ones.
Precipitation data from 1932-1998 were entered along with an actual starting population of adult males. Twenty-year periods were compared with each other. The study controlled rainfall measures with measures from a similar, nearby environment. It also took landscape variations, parasites, and destructive sampling into consideration. After the simulations were finished, the simulated populations of butterflies corresponded closely to actual observed populations. This species of butterfly had probably survived similar changes, but habitat loss by invading non-native plants and urban development reduced its ability to reestablish itself.
The study showed that extremely wet or extremely dry years showed up more frequently, and the variability was statistically significant by the end of the study. Annual rainfall appeared to be increasing too, but that wasn’t shown to be significant yet. This study does not confirm that global warming caused the variation in precipitation, but the variations are consistent with predicted global climate models. Multiple simulations using variously controlled data showed that the extinction of the butterfly was directly related to climate change.