Source:
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0005794
Glass GE, Gardner-Santana LC, Holt RD, Chen J, Shields TM, et al. (2009) Trophic Garnishes: Cat–Rat Interactions in an Urban Environment. PLoS ONE 4(6): e5794. doi:10.1371/journal.pone.0005794
This article questioned the potential negative impacts of decreasing predator species and the resulting effects this decline could have on an ecosystem, including on prey inter-specie disease and the resulting impact this could have on humans. The focus of this study was on cats and rats in the urban environment of Baltimore, Maryland. The study was specifically concerned with the ratio of cats to rats in the urban environment of an alley. The experimenters seemed to first have hypothesized that the number of predators and prey were directly correlated. To determine if this actually were the case, experimenters manipulated the rat populations in an urban alley, in which they trapped and took away rats twice, once a year for two years. They wanted to examine the relationship between the numbers of predating creatures to the number of prey creatures, and ultimately observed that although the decrease in rats temporarily decreased the rat population, it had “no negative long-term impact on the size of the rat population” and “the sizes of the cat population during the two years were also unaffected by rat population perturbations.” This observation suggests that the rat population is not necessarily immediately impacted by predators. This study assesses the potential benefits, or lack there of, that would result from an introduction of predators to stabilize and control the rat population over a long-term span of time. According to this study, this does not seem to be the best solution to excessive rat populations in an urban environment since the “structure” and not the “abundance” of rats were significantly impacted by the larger predation population in comparison to the prey population. These results lead me to question what solutions we can implement in our urban environment in New York City, where rats are cohabiting, to an extent,with humans. The “long-term goal” of this study was to ultimately examine the link between predation and prey and the resulting impacts on urban ecological systems and the spread of diseases should the prey population increase as a result. This is particularly relevant to NYC where so many people are in contact with rats. If we were to introduce, or increase, the number of rat predators to the city we would have to ensure this predator would indeed use this rat as part of a daily diet and that it would not just change the structure but rather have long-term impacts on the abundance of the rat population since this study suggests otherwise. To fully accept this study’s results it would be beneficial to conduct similar experiments or to read more experiments with a similar focus.
