Bad Times Ahead for Mountain Butterflies

Butterflies that live in mountains are going to be more vulnerable to global climate change.

This conclusion has been reached in a study on butterflies of the genus Erebia by researchers from the Autonomous University of Madrid (UAM) and the National Museum of Natural Sciences (MNCN), dependent on the Higher Council for Scientific Research (CSIC), in Spain the three entities.

To test how climate change will affect these butterflies, the researchers made potential distribution models that show favorable areas for the species under different climatic conditions.

“The models look for areas that in the future share the climatic conditions in which the species are currently found, taking into account different predictions of temperature and precipitation in the coming years. In addition —explains UAM researcher Helena Romo— we have considered two scenarios, one more drastic, in which an increase in temperature of 3.7 degrees Celsius is expected for the year 2100, and another more optimistic, in which the expected temperature increase is 1.8 degrees”, he continues.

What the models project

The genus Erebia comprises 19 species distributed in mountainous areas of the Iberian Peninsula: Pyrenees, Cantabrian System, Central System, Iberian System and Sierra Nevada; seven of which are endemic species (they are only found naturally in these geographical areas).

The results show a dramatic reduction in the number of climatically favorable areas for the 19 species.

In fact, 16 species of the genus would completely disappear from the Iberian Peninsula in the most drastic scenario in the period 2061-2080 (centered on 2070).

Specimen of the species Erebia palarica. (Photo: Enrique García-Barros Saura)

The “good news” is that of the three species that present some climatically favorable area in the future, two of them are endemic (E. palarica and E. hispania). But the reality is that, even in a less drastic scenario, the forecasts are that at least eight species will not find areas to survive in the period of years between 2041–2060 (centered on 2050).

“Even for one of the most common species and with the widest distribution in the Iberian Peninsula, such as Erebia triarius, a significant decrease in favorable areas is predicted in the future. Other species with a more restricted distribution do not present any favorable zone for these scenarios”, explains Rob Wilson, MNCN researcher.

Because most of the species of the genus Erebia are distributed in the Pyrenees or the Cantabrian Mountains, most of their known populations are found within the existing network of Protected Natural Areas of the Iberian Peninsula.

“However,” Wilson points out, “it would be interesting to include new areas where favorable conditions are predicted for these species in the future, so that they can offer greater protection to species most threatened by climate change.”

In sum, the models predict that the 19 species of Iberian butterflies of the genus Erebia are extremely vulnerable to climate change, with declines expected for the period centered around 2070 being greater.

In fact, some species already occupy the highest areas of the study area and are expected to lose their habitat regardless of the year or scenario considered.

According to the authors of the study, the endemic species of this genus could act as umbrella species for the design of new spaces in the Network of Protected Spaces of Spain or other conservation measures.

“The measures that could be applied for these priority species would include monitoring the most threatened populations or species and the state of their main habitats: the maintenance of a wide variety of microclimates through an ecological restoration strategy at different altitudes so that the species can adapt to the conditions imposed by climate change, and of course, achieve a global reduction in greenhouse gas emissions”, concludes Helena Romo.

The study is titled “Modeling the scope to conserve an endemic-rich mountain butterfly taxon in a changing climate”. And it has been published in the academic journal Insect Conservation and Diversity. (Source: UAM)