Tag: alien species

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 species had a very high invasion rate.

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.”

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Original source:

Liu M, Yang M, Song D, Zhang Z, Ou X (2016) Invasive Acacia mearnsii De Wilde in Kunming, Yunnan Province, China: a new biogeographic distribution that Threatens Airport Safety.NeoBiota 29: 53-62. doi: 10.3897/neobiota.29.7230

Posing a significant threat to the native biodiversity in Japan, specifically that of threatened aquatic insects, some alien fishes, such as the bluegill, have become the reason for strict prohibitions. All activities potentially capable of introducing the species into the wild are currently punishable by either a fine of up to 3 million yen for a person (100 million yen for corporations), or a prison sentence of up to 3 years.

Recently, ten years after the law has been adopted, illegal release of bluegill fish has been reported for the first time with the help of a post on Twitter from Akinori Teramura, undergraduate student at the Tokyo University of Marine Science and Technology and second author of the present study. The case is reported and discussed by him and two scientists, affiliated with Kanagawa Prefectural Museum of Natural History, Japan, in the open-access journal ZooKeys.

In June 2015, Akinori Teramura tweeted two photographs of the invasive bluegill fish, both adults and juveniles, along with two young goldfish, which do not belong to the local fauna, either. In his post he identified the species and shared his surprise at the irresponsibility of the people who had released the fish. When lead author Dr Yusuke Miyazaki saw the tweet, he signalled his colleagues with the idea to publish the information as a scientific report.

The student found them in an outdoor public pool in Yokohama city, Japan, while it was being cleaned before being opened ahead of the summer. Usually, these facilities are closed to the public during the colder seasons and it is then when native aquatic insect species, such as dragonflies and diving beetles, find spawning and nursery habitats in them. Curiously enough, though, the pool had been isolated from natural waters since its construction.

Therefore, the researchers conclude that the alien fishes have most likely been released from an aquarium from a local shop or an aquarist who no longer wanted them. However, the authors note that according to the law, keeping bluegill fish in a home aquarium is illegal as well.

“Our report demonstrates an example of web data mining in the discipline of Citizen Science,” say the authors. “Web data mining has been rapidly developing over recent years, and its potential continues to expand.”

“Community awareness of this issue needs to be improved, and widespread reporting of cases such as this one will help,” they conclude.

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Original source:

Miyazaki Y, Teramura A, Senou H (2016) Biodiversity data mining from Argus-eyed citizens: the first illegal introduction record of Lepomis macrochirus macrochirus Rafinesque, 1819 in Japan based on Twitter information. ZooKeys 569: 123-133. doi: 10.3897/zookeys.569.7577