- Climate change may force the Himalayan langurs to move out of forests in protected areas in western Himalayas in India and Nepal, to forests that are outside protected areas.
- As the species move into unexplored forest areas, their introduction into these ecosystems may lead to conflict, initially between the langurs and wildlife communities, and then humans.
- Adaptive spatial planning is advocated and management of forests outside protected areas will merit required attention for conservation and planning.
Climate change is likely to force the white furred Himalayan langurs (Semnopithecus schistaceus) out of protected forest areas in the western Himalayas in India and Nepal, to forests that are outside those areas, in the next three decades, states a recent study in Global Ecology and Conservation journal.
“Our modeling predicts that the distribution of the species is likely to shift towards the eastern Himalayas as the western range will be lost in climate change scenarios. At present, the species is mostly present in protected areas (PAs) but because of climate change, the langurs will find suitable climatic conditions in areas that are outside PAs (territorial forests),” said lead author Lalit Sharma.
“The required conditions which are suitable to the species will also shift to other forested areas which are outside the PA network that means such areas, which are not suitable to species today, may become liveable in the future,” Sharma, Zoological Survey of India, told Mongabay-India.
The suitable area available for the primates, predicted to be 24,240 square km at present, may shrink by almost 65 percent in 2050, according to the study, that warns of a drastic decline in habitat areas in the western Himalayas in India while an expansion in some areas of southeastern parts of Nepal for the langurs.
Sharma and colleagues who carried out a species distribution modeling study to map the impacts of climate change on the species in the two south Asian countries, emphasised that the management of protected areas and territorial forests will need to be fine-tuned to climate change, riding on new data and updated climate knowledge.
“Data on species distribution in climate change scenarios can be used in management of territorial forests and protected areas for conservation and planning purposes, especially for species such as Himalayan langur, that can survive in a range of habitats. The areas outside PAs are going to be important in the future,” said Sharma.
Himalayan langur (HL) is a leaf-eating primate, distributed along the Himalayas, ranging from north-western Pakistan, through Jammu and Kashmir, Himachal Pradesh and Uttarakhand in the western Himalayas in India, to Nepal in the east.
These little-studied langurs are the only primate species found in the higher Himalayas, a landscape witnessing a rapidly altering climate linked to global warming. Climate change amplifies threats of forest degradation, human-langur interactions, and unsustainable forest use, for the langurs.
Sharma explained that taxonomic confusion over the species has led to a deficiency in the understanding of their geographic range and their vulnerability to future climate has not been studied. Earlier thought to be different species, the group of langur species in the Himalayan range, comprising Semnopithecus ajax, Semnopithecus hector and Semnopithecus schistaceus, is now proved to be one single species (S. schistaceus). There is a lack of census data and IUCN status is yet to be updated for the species, said Sharma.
In India and Nepal, the scientists found that the suitable habitat area for the langurs is 24,240 square km, an area slightly larger than the state of Meghalaya. Out of this total suitable habitat area, 4000 square km (16 percent) is spread over 54 protected areas (19 national parks, 20 wildlife sanctuaries, 15 conservation reserves). These include Dachigam National Park (NP) and Overa-Aru Wildlife Sanctuary in India, Chitwan NP and buffer zone, Annapurna conservation area and Langtang NP in Nepal. Most of the suitable habitat area (84 percent) of langurs is outside PAs, the study found.
Expected range expansion and range contraction for the Himalayan langur
The scientists used the ‘Representative Concentration Pathway’ or RCPs to model climate change and build scenarios about the impacts of climate change on langur distribution in the Himalayan region. RCPs represent different emissions, concentration, and radiative forcing projections leading to a large range of global warming levels. The RCPs range from very high (RCP 8. 5) through to very low (RCP 1.9).
The study considered RCP 8.5 (maximum emissions and least mitigation efforts) and RCP 4.5 (an intermediate scenario, which assumes that emissions will be reduced by 2050, and different mitigation measures will be considered).
Most of the current PAs will acquire novel climatic conditions in both the RCPs in 2050 and 2070 which will not be suitable for the species to sustain, reiterated the scientists.
As many as 35 PAs are predicted to become fully unsuitable and 11 PAs partially unsuitable by 2070; while eight new PAs are expected to gain suitable habitat area (such as Kanchenjunga National Park) and 10 PAs are expected to lose some area, gain some areas and also maintain some areas intact as suitable habitat, by 2070.
“Overall the suitable habitat area is predicted to decline by 64.6 percent in 2050; 64.1 percent in 2070 in RCP 4.5; and 63.6 percent in 2050, 20.3 percent in 2070 in RCP 8.5,” said Sharma.
The Himalayan langur seasonally migrates, from a lower elevation to higher during summers to avoid warm climate, and in winters it comes down to lower elevation. However, climate change in the western Himalayas in India may leave fewer alternative habitat areas for its migration.
There is a likelihood that more areas higher up in the mountains may become fit for living for the species. “This is possible in case the species could sustain a viable population till 2070. At higher emission scenarios the species range may enhance because of the creation of more space for species to occupy because more snow-covered areas will disappear and become suitable to the langurs,” said Sharma.
But as the species move into unexplored forest areas, their introduction into these ecosystems may lead to conflict, initially between the langurs and wildlife communities, and then humans that are already present in those areas.
“The managers of protected areas should be well equipped with scientific information so that species refuge can be safeguarded. Adaptive spatial planning is necessary to develop a climate change adaptation strategy,” said Sharma.
Adapting forest management to climate change predictions
Another study has advocated adaptive spatial planning because it allows decisions to be improved with new data, as knowledge accumulates on management within particular contexts, and to fine-tune spatial management arrangements to fit constantly changing social-ecological systems.
As of July 2019, India has 870 protected areas covering 165,088.36 sq. km, which is five percent of the total geographic area of the country. However, 21.67 percent of India’s total geographical area is under forest cover.
In Indian forest management system, PAs are managed with a focus on flagship faunal species whereas the non-PAs or the territorial forests are managed under the working plans. These working plans are focused on production forestry where treatment remedies are provided for enhancing the productivity of the forests.
“Considering the species is going to move to other forested areas in a climate change scenario, we can incorporate the data and insights when we frame the working plans for territorial forest divisions. The Working Plans have a tenure of 10 years,” said Sharma. “If the WP division of the state forest division knows that a certain area will become important in a climate change scenario, they can incorporate data to adopt strategies for the upcoming tenure. Gradually these areas can come under protected areas.”
In 2014, India came out with the National Working Plan Code, the most recent working plan code that aids in developing a working plan for a forest management unit (FMU) following a standard procedure.
“The remedies that are given are very generalistic. At that time, there was more focus on forestry and less on species living in that specific area. While in the Management Action Plan for Protected Areas there is more focus on animals but less on forestry. But much of the forests are outside protected areas and we need specific strategies for conservation and planning because these areas will be important in the future,” Sharma reiterated.
A suite of threats in addition to climate change
Primatologist Himani Nautiyal who studies Himalayan langurs in the Garhwal Himalayas, extending through a major part of the state of Uttarakhand, agrees with the modeling predictions and that climate change adds another layer of threats.
“Currently in their Garhwal Himalayan range degradation of oak forests in the home range of langurs is a major challenge. Oak is the dominant tree species found in the Himalayan zone and dependency of local communities on oak forests for livelihood is quite high and this is the reason why we are losing these dense forests. This, in turn, is affecting the langurs,” Nautiyal, who is pursuing a Ph.D. in Primatology, Kyoto University, Primate Research Institute, Japan, told Mongabay-India.
Nautiyal researches langur-human interactions in the Mandal valley in Uttarakhand in the Garhwal Himalayas, where Banj oak (Quercus leucotrichophora) branches are typically removed during winter for livestock fodder and for fuel.
Her 2015 study showed that oak was one of the most important foods in the winter diet of the species and that langurs preferred Banj oak trees, especially at high-density sites, over other tree species as food and also as sleeping trees.
Loss of dense oak forests in their home ranges drives them to raid agricultural fields for food, causing high levels of crop damage. Moreover, the langurs were unable to utilise all parts of their home range equally because of the loss of high-density oak patches. This, in turn, seemed to make them frequently re-use some sites more than others, leading to overcrowding at the sleeping sites and a further reduction of their food resources near these sites.
“They face two sets of challenges when they come closer to agricultural fields. They are harassed by local communities, they are poisoned as well. They are also attacked by domestic dogs and they are hunted for meat and for the purported medicinal value of their liver,” said Nautiyal.
“Climate change is an upcoming challenge and with the loss of their natural habitats, they will be forced to come in close proximity to humans as we already see it happen. It will be difficult to conserve the species without their habitats,” she said.
Based on the results of their study, Nautiyal and colleagues have already identified and begun to implement three short- and long-term activities to help mitigate human-langur conflict in the Mandal valley. These include replanting efforts, environmental education and outreach and empowerment of women in the community.
Banner image: Himalayan langurs are highly social animals ranging from north-western Pakistan, through Jammu and Kashmir, Himachal Pradesh and Uttarakhand in the western Himalayas in India, to Nepal in the east. Photo by Himani Nautiyal.