Sir Joseph Dalton Hooker, one of the greatest explorers of the nineteenth century, and the closest friend of Charles Darwin, was 32 years old when, in 1849, he visited the then remote kingdom of Sikkim in the Eastern Himalaya. Over a two-year period, he travelled widely in the Darjeeling-Sikkim Himalaya and described over 3,000 species of plants for the tiny state of Sikkim, 7,096 square kilometre in size.
After Hooker returned to England he went on to write, over a 25-year period, the seven-volume Flora of the British India —the first and still the only authoritative account of the plants of the vast sub-continent. June 30, this year, marked Hooker’s 200th birth anniversary.
While celebrating the bicentenary of Hooker’s birth and his enormous contribution to the documentation of biodiversity in one of the hottest global hotspots of biodiversity, we should pause and reflect on the current status of the documentation of India’s amazing plant wealth, the pace of global environmental change that is impacting this plant wealth, and the prospects for sustainability in the Himalaya, particularly the Eastern Himalaya, where Hooker conducted his most notable studies that led to the compilation of the flora of a vast region.
It is questionable if the pace of cataloguing life in India or South Asia has advanced very much since Hooker’s time. The descriptions of many plant genera on which Hooker worked still remain incomplete. Hooker, for example, wrote to Charles Darwin about the taxonomic status of Impatiens: “I took down the most difficult genus of Indian plants I could think of to work at:—viz. Impatiens of which there are just 100 Indian species! I have made the first draft of a monograph of them…” (J.D. Hooker to Charles Darwin, December 2, 1857: https://cudl.lib.cam.ac.uk/view/MS-DAR-00104-00178/3). Since the pioneering work of Hooker, species of Impatiens from the entire Himalaya or India have not been fully catalogued.
Hooker’s exploration of the Indian sub-continent was very limited. He could visit only a small part of the huge sub-continent. In present-day India alone, the genus Impatiens, for example, is now known to contain more than twice the 100 or so species estimated by Hooker: the British India at the time of Hooker included Pakistan, Bangladesh and Myanmar. New species of Impatiens from the Himalaya are being described every now and then. Thus, further work is necessary to fully document India’s incredible diversity of plants, especially from the unexplored regions of the Eastern Himalaya.
Stupendous effort
It is interesting that Hooker single-handedly organised the effort to write the flora of a sub-continent, extraordinarily rich in species. British India at Hooker’s time perhaps had more than 25,000 species of flowering plants. Hooker described about 16,000 of these species. With modern digital and other tools, and a sound infrastructure for field work that Hooker could not dream of, Indian scientists have a great opportunity to complete Hooker’s unfinished task, and to produce a complete, modern authenticated list of India’s plants.
The neglect of plant exploration in India, particularly in the Eastern Himalaya, where Hooker began his professional career, is ironic. The Eastern Himalaya, along with Hengduan Mountains, matches the Andes that include the lowlands of South America, as among the world’s richest centres of plant diversity. There are thousands of economically important species, many such as rhododendrons, orchids, poppies, primroses and, of course, Hooker’s balsams (Impatiens) of immense horticultural significance. Many species remain to be discovered: despite the lack of systematic exploration, from 1998 to 2014, according to the World Wildlife Fund, India, 375 species of new plants were discovered in the Indian part of the Eastern Himalaya.
Changing landscape
At the same time, the Himalaya is changing rapidly. When Hooker visited Darjeeling and Sikkim, he writes in his Himalayan Journals that he could see dense forests all around him. These forests now exist as a patchwork of fragments, and are threatened by a host of factors such as expanding populations, infrastructure development (roads and hydropower) and climate change.
There is thus an urgent need to conserve remaining biodiversity and the associated ecosystem services, particularly in the light of a recent report about the world wide “annihilation” of the biological world, also termed as the sixth mass extinction. Our country, for instance, has lost more than 50% of the populations of many of our large mammals.
This decimation of life is particularly ironic when many species are yet to be discovered, and when the evidence is mounting that nature provides us with a host of economic benefits that we had not thought of before. Take for example a recent, widely publicised, study that shows that economic flows from six selected tiger reserves range from US$128 million to US$271 million per year.
A commitment to fully document the richness and the value of life in the Himalaya for the benefit of our society might be the best way to celebrate the birth anniversary of one of the greatest plant explorers of the world.
Kamal Bawa is Distinguished Professor of Biology at the University of Massachusetts, Boston and the President of the Bengaluru-based Ashoka Trust for Research in Ecology and the Environment (ATREE). R Ganesan is a Fellow at ATREE. The views expressed are their own.
