All Aflutter about Climate Change

Photo: Astrid Caldas

Climate change is among the most daunting environmental problems faced by the world today.  What with sea level rise, droughts, fires, and floods, it seems that the world is being taken by storm (pun intended).  Yet, the impacts of climate change on butterflies, and what we can do assist them, is still a fledgling field.

Butterflies and moths are members of the order Lepidoptera, and provide an array of what we call ecosystem services, including pollination.  They are also excellent indicators of environmental quality, and have an important aesthetic value, being enjoyed by people around the world.  Climate change is likely to affect Lepidoptera in many ways.  Most commonly, species will experience changes in range, distribution, and population sizes.  Another way that Lepidoptera may respond to climate change is through phenological changes Species are already shifting ranges due to climate change, usually moving to higher latitudes or elevations.  Species are emerging earlier in the spring due to warmer temperatures.  There are many instances of disruption of essential interactions with food plants and prey.  And other effects of climate change are yet unknown.

The most recent issue of the Journal of Insect Conservation was dedicated exclusively to Lepidoptera conservation, but only a small fraction of the papers dealt with climate change.  When we consider all the real and potential impacts of climate change on Lepidoptera, the number of studies addressing butterfly conservation under a changing climate is worrisome.  One article did a literature review of all papers in leading journals published on ISI Web of Science between January 2005 and December 2009 about climate change and/or biodiversity. Only 9 out of 73 papers that showed a link between climate change and declining biodiversity studied insects, 8 of which dealt with Lepidoptera. According to the author, these few papers clearly showed Lepidoptera to be very sensitive to climate change: butterflies in Europe and North America have shifted their distributions due to recent warming, species in temperate regions have been showing phenological changes related to an earlier onset of spring, and bioclimate models of the distributions of 69 butterfly species in Mexico, South Africa and Australia contributed to the estimates of extinction risk from climate change for 1,103 species in total. 

My own search on climate and Lepidoptera in the Web of Science just last month (done without a set time frame) yielded about 50 papers.  Although that is not a comprehensive search, it is certainly not impressive!  Below is a breakdown of the focus of the papers:

Focus of paper Number of studies
Review article focusing on CC     9
Predictions under CC    15
Effect of CC on single species    11
Effect of CC on assemblage    16
Effects of CC on species interactions     6

 

I recently attended the Annual Meeting of The Lepidopterists’ Society with a call to action: Lepidoptera researchers should be leaders in documenting phenological changes of butterflies and moths in response to climate change.  Specifically:

  • Include climate-relevant information in the society’s Season Summary publication of field observations.  In addition to range extensions, host plant associations, and population dynamics, I proposed that they make an effort to include consistent first sightings of species known for a long time from specific locations.  Also, include any changes in host plant association, phenology disruption, or other change in a known pattern that can be related to a warmer climate.
  • Leverage these phenological observations by participating in the National Phenology Network, a national-level effort to monitor the impacts of climate change on plants and animals in the US.  It currently has only 12 Lepidoptera species on its list, so I urged the society to become a partner and increase the number of species in that list.  They would bring specialized input to the network, whose capabilities would be of much value to conservationists. 

If we are to keep enjoying butterflies and moths for years to come, we need more climate change-related studies.  We need to be aware of climate change-induced changes in Lepidoptera.  We may need reintroductions and managed relocation of species whose populations are declining and that have adequate, available habitat that could sustain a viable population under a warmer climate.  The time to act is now – otherwise we may lose some of the most beautiful creatures ever to flutter on earth 

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- who has written 12 posts on dotWild.

Astrid Caldas is the Climate Change & Wildlife Science Fellow for Defenders of Wildlife. Astrid provides scientific support for Defenders, including providing technical assistance for integrating climate adaptation into programs, doing synthetic research, and publishing papers and reports on climate and wildlife issues.

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