Curd, B. (2017, March 13). Callery pear: Beauty or beast? Horticulture agent explains invasive species now listed as ‘severe threat’. Features | The Advocate-Messenger. Retrieved March 14, 2017, from https://www.amnews.com/2017/03/13/callery-pear-beauty-or-beast-horticulture-agent-explains-invasive-species-now-listed-as-severe-threat/.
In Boyle County of central Kentucky, a popular spring blossom is that of the Callery pear plant. It was originally introduced to the United States in 1908 from China because it was able to combat the bacterial disease “fire blight” that was harming other fruit crops. The trees became popular for their beauty and ability to survive in many different climates – in 1962, the tree became one of the most widely planted street trees in urban cities throughout the country. However, in 1990, the plant experienced a population explosion and grew invasively throughout the southern United States. Now, states like Kentucky are attempting to eliminate the species through genetic modification and tree removal.
I’m curious why certain species become generalists while others remain specialists. The Callery pair, for example, can grow in how, humid climates, as well as climates that reach -32 degrees Fahrenheit. Wouldn’t every plant benefit from adapting to a greater range of temperatures for greater growth success? Maybe certain species established themselves later than others and are still in the long evolutionary process of becoming more adaptable. I also wonder if the Callery tree has any unhealthy affects on the overall ecosystem around it. If a species is nonnative and its population explodes, yet it does not affect the ecosystem around it negatively because it serves similar purposes to existing native species, is it still considered “invasive”? Would one still want to exert efforts to reducing its population, as scientists and environmentalists are attempting to eliminate the Callery tree?
There is an issue with how humans address species problems of endangerment and invasiveness. If a species is aesthetically pleasing, humans will want to keep it regardless of how it affects the habitat. Many people only care about how the image looks or how cute the animals is, which can become deadly for other species in certain environments because it poses a threat. These aesthetically pleasing species could potentially hurt a keystone species, which would prove to be disastrous for the entire ecosystem.
You ask some good questions, Martha, I was wondering some of the same things! I’m also curious as to how the Callery pear tree impacts its environment. To my understanding, there are countless of invasive species in the United States and they must negatively or positively affect their surroundings on different scales. I’d be interested in knowing what constitutes an ‘invasion’ so damaging that a species must be genetically modified or removed manually to protect the preexisting ecosystem.