- A study predicts the upward shift of Rhododendron arboreum in western Himalayas in a future climate change scenario.
- The study cautions that geographic isolation due to complex terrains could endanger R.arboreum’s sustenance following its shift to higher altitudes.
- R. arboreum is ecologically and culturally important to the region where the flowers support the local economy but it is facing anthropogenic threats.
Scarlet blossoms of the rhododendron tree (Rhododendron arboreum) pop out and light up the rugged brown, grey, and green oak and deodar-draped canvas of the western Himalayas as spring gets ready to take over.
But in Uttarakhand, where the species is the state tree and supports the local economy, reports of early flowering of R. arboreum (locally called buransh) have elicited concerns over the sensitivity and responses of plants to temperature and rainfall (snow) changes in the warming Himalayas.
Adding to the growing discourse on climate sensitivity of species, their ability to keep pace with the changes, and oncoming conservation challenges, a recent study has predicted that R. arboreum is likely to move towards higher elevations in Himachal Pradesh and Uttarakhand to cope with climate change.
Present throughout the Indian Himalayan region, R. arboreum is a culturally and ecologically important tree rhododendron species occurring at an altitude of 1500-3300 metres. “In an extreme climate change scenario, a raised temperature condition could favour R. arboreum to expand its distribution above 4500 metres by 2070 in western Himalayas. Our modeling finds that average annual rainfall has a profound effect on its distribution,” said study author R.M. Panda of IIT Kharagpur.
The species can survive well between 12–17 degree Celsius and in 200–1800 mm of rainfall. “The rise in availability of moisture with increasing temperature in the future could influence its upslope movement, where the topographic connection is believed to be significant,” said Panda.
Panda cautioned that although the species will likely adjust its distributional range by moving upward (in the western Himalayas) along the elevation gradient with future climate change, geographic isolation due to complex terrains could endanger its sustenance.
Known to adapt to a range of climatic settings outside their climate ‘comfort zone’ in highly splintered habitats in India, Sri Lanka, and Jamaica, hardy tree rhododendron species such as R. arboreum, on the other hand, are responsive to changes in temperature. Tree rhododendrons are listed as endangered in southern India, as vulnerable in Sri Lanka and northeast India, and as threatened in the north-western part of its native range, including parts of India and Pakistan. In some regions, however, there is no particular concern about the conservation of tree rhododendrons. R. arboreum is the only species out of hundreds of Rhododendron species that occurs throughout the entire Himalayan mountain range, as well as in isolated temperate regions in south India and Sri Lanka, according to a study.
In Uttarakhand, buransh populations at higher elevations are said to be relatively stable and healthy, but experts have warned that gradually plants in the middle altitude region would come under pressure. Meanwhile, at low and lower-middle altitudes, a range of human activities on the species is already affecting the regeneration of R. arboreum populations.
The tree is weaved into the region’s local culture, traditional medicine, and supports its economy. Local village enterprises churn out a medley of products (juice, jams, and chutneys) derived from the flowers each year that also supplements the tourism industry in the Garhwal mountains, where walking trails that bring travelers closer to Rhododendron species are popular.
Peak flowering season stretches between February and April every year for R. arboreum which is when several local entrepreneurs harvest the blossoms. On average, 10 to 20 percent of households are currently involved in the harvest and trade of buransh flowers in four Uttarakhand districts, according to one estimate.An average collection of 4 – 30 kg per household per season fetches a household Rs. 3000 – 8000 per season from preparations of products such as juice/squash, said natural resource management expert DS Chauhan.
Investigating early flowering of R. arboreum
Ram Kisan, a farmer-entrepreneur in the Tehri Garhwal district who has been engaged in natural resource-based entrepreneurship for two decades, vouches for the importance of the flowers in generating livelihood for women.
“We engage around 30 to 40 women in the villages each year to collect the flowers. They earn money through this. Earlier local communities used to chop off parts of the tree for wood but now they don’t harm the tree because they understand that it gives them a livelihood opportunity,” said Ram Kisan.
The peak flowering this year began in March coinciding with the COVID-19 lockdown scuttling Ram Kisan’s harvest of the red-pink rhododendron blossoms for processing. According to Ram Kisan flowering appeared to be linked to snowfall and local weather conditions.
“We know that when the snowfall is more in a particular year, the flowers will bloom later and they will sprout in large numbers. In the year the snow is not so thick, the flowers bloom earlier and they are not in large numbers. This year the snow was good till March so the flowers came later and they blossomed in large numbers but we could not pluck them this year as we do every year,” Ram Kisan told Mongabay-India.
“In my observation, the flowering depends on snowfall and local weather. Flowers bloom in January-February if the condition is dry and not much precipitation (snowfall) has occurred before that. But when the snow falls thick and it’s very cold, the flowers bloom from March to May. If the temperature is a bit warmer then it flowers earlier.,” Ram Kisan told Mongabay-India.
Reports of early flowering broadly attributed to climate change, have, however, evoked a guarded response from a section of experts and officials.
Prompted by frequent media reports on early flowering being broadly attributed to climate change, plant physiologist I.D. Bhatt and colleagues studied evidence of changes in flowering phenology of R. arboreum in Kumaon Himalayas using meteorological data and herbarium records.
In a paper published in 2014, Bhatt said real-time field observations (2009–2011) showed peak flowering during early February to mid-March in consonance with long-term increase in seasonal (winter and post-monsoon) and annual average maximum temperature.
Additionally, modeling using real-time field observations and herbarium records (1893–2003) indicated 88–97 days early flowering over the last 100 years.
In general, most of the old literature indicates flowering phase for R. arboreum from March to May, with occasional flowering in January, said Bhatt. But the study revealed 47–75 percent of trees in the study site bloom during February–March, providing evidence of a shift in flowering from spring to winter.
“So we can say the species is sensitive to temperature changes. But we need further research across the state to improve our understanding of the effects of climate change on species and on the ecology of the region,” Bhatt of G.B. Pant Institute of Himalayan Environment and Development, Almora, Uttarakhand, told Mongabay-India.
In 2018, the Uttarakhand forest department initiated a long-term study to understand if certain floral and faunal species can provide indications of climate change. The study also includes R. arboreum.
An Indian government report underscores the warming in the HKH region with a temperature rise of about 1.3 degree Celsius observed during 1951–2014. It said that the future warming in the HKH region, “which is projected to be in the range of 2.6–4.6 degree Celsius” by the end of 2100, “will further exacerbate the snowfall and glacier decline leading to profound hydrological and agricultural impacts in the region.”
Revisiting policies and framing new ones
As much as 71 percent of the state’s geographical area is under forests, according to the Uttarakhand Action Plan on Climate Change which notes fluctuations in the flowering behaviour of plants (e.g. Renwartia spp), shifting of cultivation zones of apple (the zone has moved by 1000 m to 2000 m), reduction in snow in winter, rise in temperature, increasing intensity and frequency of flash floods, drying up of perennial streams, among some of the reported climate change-induced changes in the Uttarakhand Himalayas.
It also states that the upward shift of the tree line and plants will have severe repercussions on poor people’s livelihoods, especially increasing the burden of women who are responsible for fetching fodder and firewood, access edible parts of plants to augment their food security and gather non-timber forest products for a livelihood.
According to IUCN’s The Red List of Rhododendrons, Rhododendrons grow in areas of high rainfall and high humidity on acidic soils, conditions under which few plants would survive. Therefore, their role in “slope stabilisation and watershed protection should not be underestimated, particularly in the Himalayas where so many of Asia’s major rivers start; nor should we overlook the role of rhododendrons in providing the structure of plant communities which support a wealth of biodiversity.”
Recent research by University of Exeter scientists has shown that plant life is expanding in the area around Mount Everest, and across the Himalayan region. Scientists used satellite data to measure the extent of subnival vegetation – plants growing between the treeline and snowline – in this vast area. Authors said while a lot of research has been done on ice melting in the Himalayan region and it is important to monitor and understand ice loss in major mountain systems, subnival ecosystems cover a much larger area than permanent snow and ice and “we know very little about them and how they moderate water supply.”
Echoing Bhatt, forester Koko Rose also stressed the importance of corroborating local observations with scientific studies to establish climate change impacts on the species. “One of the conservation issues is the overharvesting of flowers in some areas. Many people collect flowers from areas that are close to them,” Rose, divisional forest officer, Tehri division, told Mongabay-India.
“In Tehri district the raja (erstwhile ruler of the Tehri kingdom) had given rights to villages that they could collect any forest produce within a periphery of 8 km from their village. So that still continues. But that time the population pressure on natural resources wasn’t as much as it is now. So there is a need to revisit those old policies,” he said.
Forestry expert Arvind Bijalwan said unsustainable collection of rhododendron flowers may also lead to poor natural regeneration. “However, COVID-19 lockdown may be good for the natural regeneration of the populations due to limited flower plucking in lockdown. But this has to be proved,” said Bijalwan, associate professor (Forestry), College of Forestry, VCSG Uttarakhand, University of Horticulture and Forestry, Ranichauri, Tehri Garhwal.
“Rhododendron is an important species of Uttarakhand, however. It has to be managed scientifically in an organised and sustainable manner. There is a need to have more exclusive guidelines/policies to manage the species in a much better way in Uttarakhand,” Bijalwan told Mongabay-India.
DS Chauhan who specialises in natural resource management said value addition to products derived from the flowers and other parts and providing incentives to communities would also pave the way for sustainable extraction.
“The products need to be marketed properly and guidelines issued for standardisation of the extracts, especially to cater to the growing demand in the tourism industry. To plan effectively for climate change scenarios, data should be mainstreamed into sectors such as natural resource management,” Chauhan of Hemwati Nandan Bahuguna Garhwal University, Srinagar Garhwal, Uttarakhand, told Mongabay-India.
To help visualise climate data for climate adaptation and planning, the World Resources Institute India has developed the Partnership for Resilience and Preparedness (PREP) platform, a map-based, open-data online platform that allows users to access and visualize climatic, physical, and socio-economic data. This platform has been developed and piloted in Madhya Pradesh and Uttarakhand.
“In the Indian context, if you look at the resilience part of it, everything is in silos. Information in sectors such as agriculture, forestry, water, etc. is generated and consumed by the particular sectoral officials. There is not much interaction between sectors and it is very compartmentalised in how the data is exchanged. PREP helps in data visualisation and understanding the symbiotic relationship between different sectors such as water and forestry or agriculture,” Nambi Appadurai, Strategy Head, Climate Resilience Practice (CRP), WRI India, told Mongabay-India.
PREPdata aims at encouraging adaptation practitioners, data developers and innovators, private and public decision-makers, and resilience policy experts to use the platform to analyze vulnerability and build better plans for climate change adaptation.
“In Uttarakhand, we built data content in three sectors, tourism, water and agriculture, which will help mainstream the State Climate Change Cell’s agenda by providing sectoral agencies better access to data and vulnerability assessments,” said Appadurai.
Banner image: R. arboreum near Munnar, Kerala. R. arboreum is adaptive to a wide range of settings and is found throughout the Indian Himalayas and also in south India. Photo by MurielBendel/Wikimedia Commons.