New study reveals humans cause more evolution than extinction of species

While species across the world are rapidly going extinct due to human activities, we are also causing rapid evolution and the emergence of new species, a new study has found.

A growing number of examples show that humans not only contribute to the extinction of species but also drive evolution, and in some cases, the emergence of entirely new species, said researchers at the University of Copenhagen in Denmark.

This can take place through mechanisms such as accidental introductions, domestication of animals and crops, unnatural selection due to hunting, or the emergence of novel ecosystems such as the urban environment.

"The prospect of 'artificially' gaining novel species through human activities is unlikely to elicit the feeling that it can offset losses of 'natural' species," said Joseph Bull from the Centre for Macroecology, Evolution and Climate at Copenhagen.

"Indeed, many people might find the prospect of an artificially biodiverse world just as daunting as an artificially impoverished one," Bull said.

The study highlights numerous examples of how human activities influence species' evolution.

For instance: as the common house mosquito adapted to the environment of the underground railway system in London, it established a subterranean population. Now named the 'London Underground mosquito', it can no longer interbreed with its above ground counterpart and is effectively thought to be a new species.

Unnatural selection due to hunting can lead to new traits emerging in animals, which can eventually lead to new species, and deliberate or accidental relocation of species can lead to hybridisation with other species.

Due to the latter, more new plant species in Europe have appeared than are documented to have gone extinct over the last three centuries.

Although it is not possible to quantify exactly how many speciation events have been caused by human activities, the impact is potentially considerable, researchers said.

Achieving a neutral net outcome for species numbers cannot be considered acceptable if weighing wild fauna against relatively homogenous domesticated species, they said.

However, considering speciation alongside extinction may well prove important in developing a better understanding of our impact on global biodiversity, said Associate Professor Martine Maron from the University of Queensland in Australia.

Researchers do agree that current extinction rates may soon lead to the 6th period of mass extinction. Since the last Ice Age, 11,500 years ago, it is estimated that 255 mammals and 523 bird species have gone extinct, often due to human activity, said researchers.

In the same period, humans have relocated almost 900 known species and domesticated more than 470 animals and close to 270 plant species, they said.

The study was published in the journal Proceedings of Royal Society B.