Biodiversity will suffer even if the global temperature rise is maintained at 1.5 degrees Celsius
Biodiversity and ecosystem services in the Hindu Kush Himalayan (HKH) region will be threatened and suffer severe impacts even if the global temperature rise is maintained at 1.5 degrees Celsius.
The HKH have suffered significant changes owing to climate change, anthropogenic changes due to increased human footprint and change in land cover and land use, according to the latest report from International Centre for Integrated Mountain Development (ICIMOD).
While some species are benefitting from temperature increase in the region, a majority are overwhelmingly negatively affected by the changes.
The timing of leaf-fall and fruiting has altered. This has led to a decrease in the survival of plants and threatened the vulnerability of species. For example, phenology changes have been reported in alpine ginger Roscoea species in the western Himalayas, leading to early flowering of the yellow amaryllis in the Ghizer valley in Pakistan-occupied Kashmir.
Advanced and delayed flowering of Himalayan rhododendron has been observed in Nepal and nearby HKH region whereas in northeast China, it has advanced by one day per year.
The change in snowfall patterns due to rise in temperatures has resulted in the shifting of the treeline as well.
Many plant species such as the Himalayan pine have shifted upwards at the rate of 11 to 54 metres per decade in the western Himalayan regions of India. A shrub species Juniperus polycarpos has been found at 4,000 above the treelike.
About 90 per cent of the endemic species in the Sikkim Himalayas have displaced at the rate of 27.53 to 22.04 metres per decade. Many species, including Potentilla pamirica found in the northwest Himalayas of eastern Ladakh, have moved upwards by about 150 metres above the plant distribution limit.
Such changes have also been observed outside India, in Nepal and the Tibet Autonomous Region in China.
While these variations have resulted in greening of most of the alpine region, browning has also been reported in some areas exposed to droughts and anthropogenic pressure due to urbanisation, shifting cultivation, especially at higher elevations.
The report further states that introduction and spread of invasive species also threatens the health, sustainability and productivity of native ecosystems.
Citing Representative Concentration Pathway (RCP) 8.5 scenario, Ageratina adenophora and Lantana camara are estimated to increase their spread by 45.3 per cent and 29.8 per cent respectively while increasing elevations above 5,000 in the Kailash Sacred Landscape of India.
Also, 75 per cent of 26 invasive plant species will expand while 25 per cent will contract, thereby threatening biodiversity and food security while causing heavy economic losses.
Declining fauna on HKH are also mentioned in the report by the authors. Mammals, insects, microbes, birds, amphibians and fishes are becoming extinct or are experiencing genetic and behavioural changes.
Shifting of the snowline upwards is likely to affect snow leopard habitats in Bhutan, Nepal, India and Myanmar by 2080. Other than snow leopards, Himalayan musk deer, golden snub-nosed monkeys and Himalayan grey langurs have already experienced range shifts with declining populations.
The major drivers attributed for such changes are loss in habitat due to fragmentation and decreased food availability. Other species such as giant panda, Asiatic brown bear, blue sheep, Tibetan antelope, Tibetan wild ass and wild yak, endemic to HKH have reduced by 44 per cent, seven per cent and 20 per cent respectively.
Birds like the satyr tragopans have shifted their habitat to higher elevations, shrinking their range. Black-necked cranes have been observed to adjust their behaviour in terms of incubation based on weather conditions and thermal needs of their eggs.
Amphibians have seen the highest impact due to climate change. The report cites that Kashmir paa frog and Himalaya paa frog, endemic to Pakistan, face extinction due to deformities, reduction in body size, metamorphosis and higher mortality.
Monocled and king cobras in the Sikkim Himalayas have moved higher from 1,000 metres to 1,700 metres. The Sikkim paa frog has reported to have advanced its breeding by three months.
Among insects, the Apollo butterfly, endemic to China, has seen a decline in population. In the Eastern Himalayas, decline in monotonic ants and caterpillar fungus has been observed across the region.
In Pakistan, 14 species of butterflies known to dwell in the Murree hills and neighbouring areas are reported to have disappeared. Emergence of new species and altitudinal changes has been reported in Chinese three-tailed swallowtail, Himalayan relict dragonfly and pests such as tea shot-hole borer. Mosquitoes have arrived in the Everest region.
The experts predict that changes in cryosphere which have already impacted ecosystems and biodiversity, will continue to cause a decline of species in the HKH.
Future estimates forecast habitat for Himalayan grey langur to spring by 60 per cent in 2050. Tibetan brown bears are expected to lose habitats by 34 per cent, while blue sheep is likely to experience it by 56-58 per cent. In case of Himalayan ibex, it is likely to reduce by 33.7 to 64.8 per cent.
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The Kiang or the Tibetan Wild Ass will also lose its habitat due to changing temperatures across the Hindu Kush Himalayas. Photo: iStock.png)
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