We know species around the planet are going extinct due to human activities, but humans are also triggering the rapid development and emergence of new species, according to a new report.
Published in Proceedings of Royal Society B, the new study summarizes the cause of manmade speciation and talks about why newly evolved species can’t just replace extinct wild species.
Many examples show humans can drive evolution via mechanisms like accidental introductions, domestication of animals and crops, unnatural selection due to hunting, or the emergence of novel ecosystems like urban centers.
“The prospect of ‘artificially’ gaining novel species through human activities is unlikely to elicit the feeling that it can offset losses of ‘natural’ species. Indeed, many people might find the prospect of an artificially biodiverse world just as daunting as an artificially impoverished one” study author Joseph Bull from the Center for Macroecology, Evolution and Climate at the University of Copenhagen, said in a news release.
Genetic data for the damselfly in Central America suggests that forest fragmentation has led to a divergence into more than one species. (Credit: Katja Schultz via Flickr)
Creating a new mosquito species
In one example of manmade evolution, the standard house mosquito has adapted to the ecosystem of the subway system in London and established a subterranean population. Now known as the ‘London Underground mosquito’, it can’t interbreed with its surface counterpart and is essentially regarded as a new species.
“We also see examples of domestication resulting in new species. According to a recent study, at least six of the world’s 40 most important agricultural crops are considered entirely new” Bull said.
Moreover, unnatural selection because of hunting can lead to new attributes emerging in animals, which may ultimately lead to new species. Planned accidental transfer of species can also result in hybridization with other species. As a result of latter, countless new plant species have appeared in Europe and gone extinct over the last three centuries.
While we cannot quantify just how many speciation events have been triggered by human activities, the effect is potentially considerable, the study team said.
“In this context, ‘number of species’ becomes a deeply unsatisfactory measure of conservation trends, because it does not reflect many important aspects of biodiversity,” said study author Martine Maron, an associate professor of ecology from the University of Queensland. “Achieving a neutral net outcome for species numbers cannot be considered acceptable if weighing wild fauna against relatively homogenous domesticated species. However, considering speciation alongside extinction may well prove important in developing a better understanding of our impact upon global biodiversity.”
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Image credit: Walkabout12 via Wikimedia Commons
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