Climate change driving butterflies moths higher up Himalayas: study

In the Syllabus

General Studies Paper III : Environment
Conservation, environmental pollution and degradation, environmental impact assessment Disaster and disaster management.

In News:

  • Rising average temperatures in the Himalayan region have driven several dozen species of butterfly and moth to habitats higher up the mountains, as per a new study commissioned by the government.

News Summary:Survey by the ZSI on butterflies and moths:

  • Results of a four-year study on Lepidoptera (the order of insects that includes butterflies and moths) in the Himalayas were recently published.
  • The Himalayas are home to more than 35 per cent of Lepidoptera species found in India.
  • The study tracked 1,274 species of moth and 484 species of butterfly in Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Sikkim, North Bengal, and Arunachal Pradesh.
    • It also identified 80 new species of butterfly and moth.
  • It was funded by the Ministry of Environment, was carried out by the Zoological Survey of India (ZSI).
  • The study tracked the movement of these insects in the Himalayas across various altitudes and ranges.
  • Tracking of the insects’ movement was possible because the ZSI has historical records of many species since 1865. Records from 1865 to 2015 were scanned and examined to make a comparative assessment.

Findings of the studyAltitudinal shift of these insects:

  • The study has found that several dozen species of butterfly and moth are moving to habitats at higher altitudes (altitudinal shift) in the mountains.
  • The survey has identified at least 49 species of moth and 17 species of butterfly that have shown “considerable new upward altitude records”, with a difference of more than 1,000 metres between their current and previously recorded mean habitat altitudes.
    • For instance, the Common Map butterfly and Tailless Bushblue butterfly, which were previously found at 2,500 m as per historical data, have now been recorded at 3,577 m at the Ascott wildlife sanctuary in Uttarakhand.
    • In Ladakh, the Indian Red Admiral butterfly was historically found at 3,900 m; it is now found at 4,853 m.
    • Moth species, including the mulberry silkworm moth and tiger moth, which would historically be found at 2,000 m, are now typically found at 3,500 m or higher altitudes.
  • Seven species in particular have started to inhabit altitudes more than 2,000 metres higher than the previous mean.
    • These include the moth species Trachea auriplena (Noctuidae), Actias windbrechlini (Saturniidae), and Diphtherocome fasciata (Noctuidae).
  • Reasons for the altitudinal shift of these insects:
    • Receding ice caps and glaciers leading to a scarcity of water in the Himalayas has been a major reason for the altitudinal shift of the Lepidoptera.
    • The increase in average temperature has also resulted in an altitudinal shift in vegetation – trees, shrubs, and plants that once grew at lower altitudes in the Himalayas are now found only higher up in the mountains.
    • Increasing human habitation also has contributed to the shift.

Identification of species richness hotspots:

  • The study identified two species richness hotspots:
    • One in West Bengal’s Darjeeling hills, where more than 400 species records were documented
    • Another in Kumaon, Uttarakhand, where more than 600 species records were found.

Identification of high diversity areas:

  • In Himachal Pradesh, two high diversity areas were identified – Dharamshala and Shimla.

Shrinking Lepidoptera habitat:

  • The Lepidoptera habitat is shrinking.
  • For instance, the ZSI predicts a decline of as much as 91 per cent in the suitable area for the Notodontidae family of moths in J&K, Himachal, and Uttarakhand by 2050.

Poaching of precious butterflies:

  • Butterflies like the Red Apollo are highly prized by collectors and are often poached.
  • One butterfly sells for up to £100 on the international market. 

Significance of the study:

  • The extension of the range of Lepidoptera due to climate change has been observed all over the world.
  • In fact, butterflies are sensitive species that are extremely susceptible to changes in climate. They are, therefore, good indicators of long-term change in climatic conditions.
  • The findings of the study will be used as a baseline indicator to track the impact of climate change on animal species over the coming decade.
  • The study brings attention to the need to devise some stringent mitigation measures to protect butterflies and moths from both human beings and the changing climate.

About: Butterflies

  • Butterflies are a diverse group of insects containing around 20,000 different species.
  • They are ecologically very significant providing range of ecosystem services.
  • India is home to about 1,300 species of butterflies.

Ecological significance of Butterflies

  • Provide Ecosystem Service of Pollination:
    • Butterflies play an important role in pollinating flowers, particularly flowers that have a strong scent and produce a large amount of nectar.
    • Like bees, pollen collects on the butterfly’s body as it is feeding on a flower’s nectar. As the butterfly moves on to a new flower, it carries the pollen with it.
  • Add to Genetic Diversity:
    • Butterflies also provide assistance for genetic variation in the plant species they that they collect nectar from.
    • Many species of butterfly migrate over long distances, which allows pollen to be shared across groups of plants that are far apart from one another.
    • Genetic diversity helps plants to be more resilient against disease and gives them a better chance at survival.
  • Indicator Species:
    • An abundance of butterflies is an indication of a thriving ecosystem. Also, butterflies are particularly sensitive to climate change.
    • Being an indicator species, they have been widely used by ecologists as model organisms to study the impact of the loss of habitat and climate change.
  • Important Part of Ecosystem:
    • Butterflies are an important component of a food chain, as predators and prey.
    • Nearly two-thirds of all invertebratescan be connected back to the butterfly on the food chain.
    • Adult butterflies and caterpillars are an important source of food for other animals such as bats and birds.
  • Natural/ Biological Pest Control:
    • Different species of butterfly can even provide effective pest control, naturally keeping plant populations healthy and disease free.

Threats to Butterflies

  • In present times, butterflies are facing range of threats like-
    • Climate Change
    • Habitat Destruction
    • Use of Chemical Fertilizers

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