So what did they find? It turns out that butterflies emerged up to three weeks earlier and reached peak numbers sooner in southern Ohio than mid- and northern Ohio. Yet warmer temperatures aren't always a good thing.
The scientists estimated heat from urbanization, calculating the percent of impervious surface within 1 kilometer of each monitoring site. When the heat was added to the already warmer temperatures in the south, seven species actually delayed their initial appearances and delayed their peak numbers.
"Butterflies need warmth from the environment to develop," said Ries, one of the researchers, in a news release. "As their environment gets warmer, they have more and more energy but at extremes, it's too hot and they die. Before it becomes lethal, too much heat can slow growth. That's why we see the delay."
In fact, the delays may leave species with fewer resources to feed on and limited time to lay eggs. It could also expose them to greater risk of predation, resulting in a smaller generation. In addition, invasive species, such as the cabbage white and European skipper, are more likely to thrive in these warmer conditions.
The findings could be useful for predicting the effects of environmental changes over the next decades, and could allow scientists to develop strategies to respond.
Source: Science World Report | 4 May 2014