Black wattle's new biogeographic distribution threatens flight safety in China

March 30, 2016
Black wattle trees at the Changshui airport. Credit: Min Liu

Black wattle, flowering trees also known as the Australian acacia, have been observed to rapidly spread around local airports in Yunnan province, southwestern China. According to the ecologists, this alien species and its extraordinary pace of invasion are to lead to new threats for both flight safety and local biodiversity. The five Chinese scientists, led by Min Liu, PhD student at Yunnan University, have their findings and suggestions for immediate measures published in the open-access journal Neobiota.

The phenomenon was investigated by the ecologists and botanists, affiliated with Yunnan University and Kunming University of Science and Technology, at Kunming's Changshui International Airport.

The black wattle is listed as being among the ''Top 100 of the world's worst invasive alien species" by the World Conservation Union (IUCN). Native to Australia, the species has been settled across the globe for more than 150 years owing to its multiple uses. However, its distribution and expansion are generally overlooked in China.

It is an evergreen fast growing flowering tree species, which is strongly dependent on sunlight and contributes to nitrogen fixation. This means that due to bacteria in its root system, the tree produces nitrogen compounds that help the plant grow and compete with other plants. Once dead, it would release these compounds to fertilise the soil.

During their investigation, the scientists observed a total seedling spread of 1800 m in 2013, with its peak growth taking place between June and November. Other population features such as number, density, height and ground diameter, also showed that the had a very high invasion rate.

Black wattle tree being measured at the Changshui airport. Credit: Min Liu

The authors conclude that black wattle has a strong potential to change the local vegetation structure and increase the risk of bird strikes. It is of urgent need that the situation is further assessed and the potential invasion threat at other airports around China and other parts of the world - evaluated.

"I have never found such a rapid expansion like the one of the black wattle trees at this airport in my career," said the Head of Bird Strike Prevention Office of Changshui Airport. "These trees grow very fast and provide good shelters for local birds, which eventually increases the probability of bird strikes at our airport. So, they must be controlled."

Black wattle's new biogeographic distribution threatens flight safety in China
The expansion of black wattle in the grass-planting area near the west gutterway at the Changshui airport (June-November 2013). Credit: Min Liu

Explore further: Alien plants and animals drive native species to extinction

More information: Min Liu et al. Invasive Acacia mearnsii De Wilde in Kunming, Yunnan Province, China: a new biogeographic distribution that Threatens Airport Safety, NeoBiota (2016). DOI: 10.3897/neobiota.29.7230

Related Stories

Alien plants and animals drive native species to extinction

February 22, 2016

Accidentally or deliberately introduced species are the second most common threat associated with recent global extinctions of animals and plants, a new study from the University of Adelaide and UCL, in the UK, has found.

Recommended for you

Ten months in the air without landing

October 27, 2016

Common swifts are known for their impressive aerial abilities, capturing food and nest material while in flight. Now, by attaching data loggers to the birds, researchers reporting in the Cell Press journal Current Biology ...

Study shows mixed fortunes for Signy penguins

October 27, 2016

A forty year study on a remote Antarctic island shows that while populations of two penguin species are declining, a third is increasing. Analysis of census data from Signy Island in the South Orkney Islands reveals that, ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.