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Butterfly Populations Could Be Headed For Widespread Collapse

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Justine Alford

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clockAug 10 2015, 17:38 UTC
1673 Butterfly Populations Could Be Headed For Widespread Collapse
Green-veined white butterfly Pieris napi. Jim Asher

Far more than just a beautiful part of our natural heritage, butterflies are important because they serve as valuable indicators of healthy environments and ecosystems. They also help us assess the potential impacts of things like habitat loss and climate change on other species, such as bees and beetles, many of which provide essential services for us like crop pollination and pest control. It’s therefore pretty bad news that drought-sensitive butterfly populations in the U.K. could be headed towards widespread extinction as early as 2050, according to new research.

With the frequency of extreme weather events predicted to increase, populations may be unable to recover fully from resulting population collapses, leading to local extinction. But it’s not all doom and gloom: The study also suggests that the chances of these populations persisting, at least until 2100, could be boosted by managing landscapes and reducing the fragmentation of their habitats, although this will only be effective if coupled with substantial decreases in greenhouse gas emissions.

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“Habitat fragmentation can be reduced by restoring natural habitats such as woodland, grasslands and heathlands,” lead author Tom Oliver from the UK’s Centre for Ecology & Hydrology told IFLScience. “In many cases, this may involve devoting more land to conservation and less to food production,” a far from desirable option. But it’s not just down to the government to take action. Oliver points out that members of the public can also help avoid this impending situation by maintaining gardens, joining wildlife groups and reducing personal CO2 emissions through modifications to consumption patterns.

As described in Nature Climate Change, the scientists began their investigation by using long-term butterfly population data from numerous sites across the U.K. to assess the responses of 28 species to the extreme drought that occurred in 1995, the driest summer since recordings began in 1776. This led to the identification of six drought-sensitive species that displayed negative relationships between growth rate and aridity, and also experienced severe population collapse after the drought. These included the speckled wood, green-veined white and large skipper butterflies.

Using future projections from several different climate models and land-use scenarios, the researchers found that simply improving land management in the U.K. was insufficient to prevent widespread extinctions to these particular species by 2100. And if high “business as usual” emissions continue, then these events could take place as early as 2050. But the probability of persistence did improve with reduced habitat fragmentation, and when combined with substantial emission reductions, the chances were raised by around 50%.

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Interestingly, Oliver told IFLScience that habitat fragmentation had a stronger effect on habitat persistence than habitat area. This offers the opportunity for cost-effective, targeted habitat restoration, but he also points out that there are unfortunately lots of factors that could and are hindering such projects. A lack of awareness of the importance of the natural environment for human well-being and a lack of funding for wildlife-friendly land management are just two examples. 


natureNature
  • tag
  • climate change,

  • global warming,

  • weather,

  • butterflies,

  • drought

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