How plate tectonics, mountains, seas have kept Earth’s ‘Goldilocks’ climate
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As much as 36% of 47 protected areas in the eastern Himalayas, especially those isolated higher up in the mountains, are highly vulnerable to climate change, a study has said. It cautions that a failure to cut global greenhouse gas emissions will undercut species conservation efforts in the fragile region.

  • As much as 36% of protected areas in the eastern Himalayas are highly vulnerable to climate change, says a study.
  • Climatic changes in the past 50 years show up as a 1.3 degree Celsius rise in temperature, a decrease in summer monsoon rainfall and an increase in the frequency of extreme weather events.
  • They are most pronounced in protected areas in Sikkim, Arunachal Pradesh, Assam and West Bengal.
  • It will be “difficult” to mitigate the worst effects of climate change and conserve species unless stringent actions are taken to limit greenhouse emissions, the authors say.

Marked by a 1.3 degree Celsius rise in temperature from 1951 to 2014, a decrease in summer monsoon rainfall and an increase in the frequency of extreme weather events, all protected areas (PAs) in the eastern Himalayas shelter at least one species at high risk of global extinction as classified by the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species.

Climatic changes in the past 50 years are most pronounced in PAs in Sikkim, Arunachal Pradesh, Assam and West Bengal. Mouling National Park, for example, on the bank of the Siang river in Arunachal Pradesh, home to takins, serrows and monals, saw a one degree Celsius rise in its average annual temperature and an increase of 1.5 degrees Celsius in the average temperature in the coldest season.

These changes are “alarming” and “likely to worsen”. A recent analysis of 119 years of rainfall measurements at different rain gauge stations across northeast India, has also revealed a decreasing trend in summer rainfall since 1973, including in rainy Meghalaya, reputed for hosting the world’s wettest place.

According to the authors, efforts to build the resilience of these ecosystems to climatic changes like the creation of buffer zones and probably even assisted wildlife migration to suitable sites are needed. They add that it will be “difficult” to mitigate the worst effects of climate change and conserve species unless stringent actions are taken to limit GHG emissions; the warning comes amid the emissions increase concerns flagged by a series of reports of the Intergovernmental Panel on Climate Change.

The findings provide useful indications on the most vulnerable sites where conservation needs to be improved, where more funds can be allocated and areas that can be expanded, such as wildlife corridors and connectivity corridors that enable functional connectivity between these protected habitats. The eastern Himalayan region, in India’s northeast, is rapidly losing forested habitats, with even many protected tracts under siege from rapacious mining and illegal logging.

“Climate change directly impacts the habitat conditions essential for the survival of a species. Changes like the rise in temperature and reduction in rainfall have a notable impact on the vegetation of an area. An alteration in the local vegetation would negatively affect the wild animal populations inhabiting that area and, in extreme cases, may lead to the local extinction of species,” Subham Banerjee, lead author of the study at IISER-Kolkata told Mongabay-India.

Further, isolated habitats in high elevation zones provide little opportunity for species movement in response to changing climate, and species here might have a narrower thermal tolerance range.“Unless we limit the extent of the changes through global reduction of greenhouse gas emissions, there is little hope that some isolated high elevation sites can be rescued,” the authors warn in the study.

In Sikkim, scientists mapping frog diversity along the Teesta river’s path through the mountains and plains pointed to most amphibians being restricted to a narrow range along the river’s elevation gradient making them vulnerable to a wavering climate. These species would be unable to extend their ranges in a warming climate because they have adapted to a specific small area with a set of climate conditions.

“We need to focus outside protected areas because the forest cover is substantial outside protected areas and these areas have rich biodiversity worth conserving. We’ll have to think of a participatory approach with communities where multiuse landscapes may be prioritised for biodiversity conservation,” Robert John, study co-author, told Mongabay-India.

“Since all PAs have different habitat conditions, house slightly different ecosystems, and have different levels of human pressures, it is obvious that the “one size fits all” approach won’t work for the allocation of conservation resources,” said another study author Mriganka Shekhar Sarkar. “We suggest that PAs surrounded by a large number of human settlements aren’t suitable for expansion. Our results will help identify the areas suitable for future expansion,” said Sarkar.

The 47 PAs covered in the study account for more than 80% area of the total PA network in this region, often embedded in a mosaic of agricultural fields, pasture lands, human settlements and infrastructure. The findings have implications for India, party to the Convention on Biological Diversity, amid the push to conserve 30% of Earth’s land and sea areas by 2030 (“30 by 30” plan of the proposed post-2020 Global Biodiversity Framework).

The eastern Himalayan landscape and the studied protected areas. Photo by John et al.

“We felt that this idea of having area-based targets for planning conservation activities is fraught with problems. This scheme may encourage the formation of protected areas at locations that may be easier to protect than the sites of high biodiversity,” said study co-author Rajashekhar Niyogi, a Ph.D. student.

The scientists ranked the PAs in terms of their vulnerability by dovetailing the number of imperilled species, human footprint (change in human pressures from 1993 to 2013), and the degree of climate change in these protected areas. They used open-source global datasets. Only a small number of PAs are working well to conserve species while about 38% of the protected areas were found to be the most vulnerable when all three factors are taken into account. These include PAs in Assam, Arunachal Pradesh and West Bengal, such as Jaldapara, Manas, Pakhui and Kaziranga.

The study also finds that PAs with the highest overall vulnerability, overlap with areas of high population density, such as the Kaziranga National Park in Assam and Gorumara Wildlife Sanctuary in West Bengal. Human pressures were high where the population density of forest fringe communities was high and little forest land or resources were available outside PAs such as in Buxa Tiger Reserve in north Bengal which recently saw the return of the tiger following ecosystem restoration activities, including grassland management.

Well-connected protected areas

Indian Forest Service Officer Sonali Ghosh who has served as field manager in Kaziranga, and Manas in Assam says that Kaziranga which has seen multiple expansions in extent shows that PA conservation in India has moved from species-based to landscape-level. She says Kaziranga is a “classic case” where the need to expand the PA to secure greater habitat for the one-horned rhino has fructified over the years.

A major stronghold of the one-horned rhino, Kaziranga is home to several globally threatened animal species like the Bengal tiger, Asian elephant, wild water buffalo, gaur, sambar deer, hog deer, and the hoolock gibbon.

“This (expansion) has also been an uphill task in terms of coordination between the forest department, revenue authorities and the local community to secure more areas. Kaziranga is a lesson learnt that management plans/tiger conservation plans with strict enforcement of the road map over the plan period of 10 years are needed to save our species,” Ghosh, Deputy Inspector General of Forests at Central Zoo Authority told Mongabay-India. She was not associated with the study.

Protected areas cannot be viewed in isolation and landscape connectivity is equally important for the dispersal of species. “Corridors need to be strengthened and secured through legal mechanisms (as in the case of Bhutan and Europe) and awareness, research and capacity building to secure such areas are needed in the long term,” said Ghosh.

Forests in Buxa Tiger Reserve. Photo by Swaroop Singha Roy/Wikimedia Commons.

Ruth DeFries, a professor of ecology and sustainable development at Columbia University in New York, who works in landscapes outside PAs in central India, said the idea of protected areas as “networks” rather than isolated sites is gaining traction in the conservation discourse.

“And it’s particularly relevant in India. But that still means you’d need protected areas to be well managed to be the nodes in those networks,” DeFries told Mongabay-India, lauding India’s PA coverage at five percent of its geographic area despite the intense competition for land and human pressures. She was not associated with the study.

Terai needs more attention

In other findings, the study highlights that the PAs in Terai grassland and forest ecosystems at the foothills and low elevations, such as those in Assam, shelter a high number of threatened species requiring greater conservation efforts and high species vulnerability. For example, Manas Tiger Reserve is home to 13 critically endangered, 28 endangered, and 44 vulnerable vertebrate species. Others in that league include Kaziranga, Nameri National Park, and Amchang Wildlife Sanctuary.

The high species vulnerability in the PAs of Assam – which, according to an Indian government report, is most vulnerable to climate change in the Indian Himalayan region – “needs to be comprehensively managed by ensuring species protection across the entire region” according to the study authors.

“Our understanding of the Terai ecoregion is very limited. Within Assam itself from Orang to Kaziranga, it’s a world of a difference. If we know clusters of PAs in a specific ecoregion, then we can work out the requirements and challenges of those PA clusters linked to an ecoregion,” said John. “Our results basically give you a broad idea of the vulnerabilities that exist in different regions in the eastern Himalayas. Going ahead if we can break it down to the level of ecoregions we will get a finer understanding,” John added.

Ecoregions are areas with similar ecosystems and the same type, quality and quantity of environmental resources. The Terai’s complexity in Assam also reflects the Bramhaputra river’s dynamic nature and the landscape which is “subject to both montane effects as well as the plains effects and human interactions and high cultural diversity” which has also given rise to conflicts.

Recently, researchers tracking the movement of wildlife in Assam’s Kaziranga landscape, which is submerged by annual floods in the Brahmaputra river, to higher grounds to seek refuge, found that large herbivores such as rhinos and elephants, risk navigating human-dominated spaces, which they would otherwise avoid.

Retaining natural cover (woodlands and bamboo) even on private lands, through a participatory conservation strategy that involves local stakeholders, can provide natural cover and favour movement decisions and space use by the herbivores in response to extreme weather events, they said.

While the Global Biodiversity Framework is still evolving, to secure larger areas, Sonali Ghosh says, the OECM strategy (other effective area-based conservation measures) needs to be acknowledged and implemented at the earliest to formally recognise community conserved areas.

“India is on a strong wicket given the history of community conserved areas in the Himalayas, it is now time to formally recognise and strengthen such shared governance mechanisms,” she said.

Also Read | Poachers tranquilize rhino to remove horn in Orang National Park in Assam



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