Scientists from University College London have studied the movement of ‘alien’ bird species between 1500 and 2000AD.
They found that there was a sharp increase in the rate of introductions in the 19th century when Europeans exported birds such as ducks, geese and pheasants to new territories.
“One of the main ways humans are altering the world,” said Professor Tim Blackburn, the supervising author, “is by moving species to new areas where they do not normally occur.”
The researchers analysed the movement of almost 1,000 non-native bird species, and examined this database for patterns caused by historical events and natural environmental variation.
One conclusion from the study, published in PLOS Biology, was that areas with more native species were also home to more non-native bird species.
Additionally, the researchers found that more than half of all known introductions took place after 1950 and this trend is expected to continue, most likely due to the caged bird trade.
“The global bird trade continues to grow,” said Professor Blackburn. “It’s a worry because aliens may threaten the survival of native species.”
Find out more about this research: http://bit.ly/2k4grhl