“(BBC 26 April 2012) Non-native plant species are extending the growing season in eastern US forests by an average of four weeks, a study has suggested.

There was no difference in the start of growing during the spring, but the report found a noticeable difference between native and non-native species in the autumn.

This could have a profound impact on forest ecosystems, such as how soil nutrients are absorbed, the paper says.

The findings are published by Nature.

"There is a bit of a saying in these parts that if you go for a hike in March and you see something green, then it is an invader," said author Jason Fridley, an ecologist at Syracuse University, US.

"So I thought I would invest little bit of my time to quantify that if the invaders were waking up a little earlier in the spring, and were keeping their leaves longer in the fall, what was the significance to their ecology and their ability to get into the forests."

Prof Fridley said that his experiment, carried out over three years and involving more than 70 species, actually revealed that there was not a signal of non-native species coming into leaf earlier than native species during the spring…”

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