A global biodiversity hotspot, and a UNESCO World Heritage Site, the Western Ghats are a watershed to as many as 58 rivers. It is also home to a large number of endemic plants and animals across six states. The 1600 km mountain chain is home to more than 4,000 flowering plants, about 500 bird species, and over 300 species of mammals and amphibians (UNESCO, 2012).
At least 325 globally threatened (IUCN Red Data List) species occur in the Western Ghats. The globally threatened flora and fauna in this region are represented by 229 plant, 31 mammal, 15 bird, 43 amphibian, 5 reptile and 1 fish species. Of the total 325 globally threatened species in the Western Ghats, 129 are classified as vulnerable, 145 as endangered and 51 as critically endangered (ibid).
While a number of flagship mammals, such as the Asian Elephant and Gaur occur in these parts, endangered species such as the lion-tailed Macaque, Nilgiri Tahr and Nilgiri Langur are unique to the area. It also houses a number of threatened habitats, such as the seasonally mass-flowering wildflower (kurinji) meadows, Shola forests and Myristica swamps.
“These threats have, critically endangered Wroughton’s free-tailed bat, and the Golden frog, who are now on the verge of extinction”, points out B C Nagaraja, Assistant Professor at the Department of Environmental Science, Bangalore University.
The uniqueness of the Western Ghats, which are much older than the Himalayas, is related to the break-up of the ancient Gondwanaland, the formation of India as an isolated landmass, and finally, its moving up north to join Eurasia. This has contributed a great deal to its speciation and biodiversity , with species dispersal playing an important role here.
Role in monsoon patterns
The mountains of the Western Ghats and their characteristic montane forest ecosystems influence the Indian monsoon weather patterns that mediate the warm tropical climate of the region, presenting one of the best examples of the tropical monsoon system on the planet. The Ghats act as a key barrier, intercepting the rain-laden monsoon winds that sweep in from the south-west during late summer.
Threats to the Western Ghats ecosystem
Large-scale conversion of forest tracts began around 1854, when the British brought tea and coffee to the highlands of Coorg (Kodagu) and the Nilgiris. Rubber plantations further south in Kerala, and in recent times, the oil palm are other monoculture vegetation that has changed the ecosystem and biodiversity of the Western Ghats.
A 1997 study on deforestation in the Western Ghats using GIS remote-sensing covering an area of 81,870 sq km comprising 19 districts in Karnataka, Kerala and Tamil Nadu (Menon and Bawa, 1997) showed that over a 70 year period from 1920-1990, 40 per cent of the original natural vegetation (forest and scrub) had been lost or converted, with open/cultivated lands accounting for 76 per cent, and coffee plantations for 16 per cent of the conversion. This had resulted in extensive fragmentation of landscapes, a fourfold increase in the number of forest patches with a simultaneous 83 per cent reduction in the average sizes of forest patches (Critical Ecosystem Partnership Fund, 2016).
Burgeoning human settlements, livestock grazing, and over-exploitation of non-timber forest products are other biodiversity threats in the region. Pollution is a huge problem, with many corporate entities well-entrenched in manufacturing. Mercury leaching into the waters in Palni hills in the Nilgiris from Unilever’s thermometer plant has been a major grouse for activists since some time now. Pressure from tourism has also affected towns like Ooty. The unchecked use of agrochemicals in tea and coffee plantations has also been a threat to amphibians, and aquatic biota (ibid).
Mining for iron ore has threatened ecosystems in Karnataka and Goa. Although many mines in Karnataka have now been shut down, the damage to the top soil is yet to be countered. In Goa, mining conglomerates though, continue to pollute rivers, and wreak havoc on farms. To add to the above mentioned threats, are the usual ones of indiscriminate logging and hunting by locals, who are too ignorant and poor to conserve nature’s bounty and biodiversity.
“Consequently, it is not just a drop in the number of trees, and species, but a drop in genetic variability that threatens this region”, plant geneticist and professor of bio-prospecting and bio-conservation R Umashakar from the Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bangalore points out. “The juveniles, as compared to the mature plants in the region, have a constricted gene pool. This renders them unable to fight pestilence and other pressures to biodiversity ”, he says.
A 2003 Food and Agriculture Organisation (FAO) study by Kamalappa Ramakrishnappa in the region on medicinal plants growing in the wild showed that over-exploitation of biodiversity had affected several medicinal plants. Deforestation for agriculture, decreased rainfall and lack of pollinators due to climate change, siltation of water bodies due to several factors, and the building of dams and roads were equally to blame. The study, conducted in Devarayanadurga (near Tumkur) and Maradavally (near Shimoga) forest range with the help of local villagers, showed that there was 10 per cent deforestation in Maradavally and 30 per cent deforestation in Devarayanadurga over the previous two decades. There was also a drop in honey bee colonies to the extent of 60 per cent in Maradavally, and 90 per cent in Devarayanadurga, causing a reduction in dispersal of seeds (FAO Corporate Document Repository, 2002).
Interestingly, careless over-exploitation of medicinal and other plants by contractors for industry can affect an entire ecosystem, and take a toll on other species. For instance, removal of aloe vera and asparagus racemosus, which are good soil binders has resulted in large-scale soil erosion in the Maradavally forests. Over-exploitation of Bombax ceiba (Mahamara) for its latex has similarly brought down the numbers of honey bees. This is because the Bombax Ceiba is the main shelter tree for honey bee colonies. As a result, it has drastically reduced honey bee populations affecting the pollination process in forests and farms (ibid).
Hasiosiphon eriocephalus is a green manure crop which was once available in plenty in the forest area. This species, in addition to its nutritional value, also possesses insecticidal properties believed to protect rice fields from pests. Large-scale exploitation of the species by pesticide manufacturing companies has seen a decline in its availability.
Paddy growers of Maradavally village used Hasiosiphon eriocephalus as a green manure crop which was once available in plenty in the forests. This species, in addition to its nutritional value, also possesses the insecticidal properties believed to protect rice fields from the attack of insects and pests. Large-scale exploitation of the species by the pesticide manufacturing companies during the last few years has deprived local people of its use.
Climate change and the western ghats
In the past, pollen analytical studies in the Western Ghats related to 20000 years had indicated savannization of tropical moist forest in North Kanara (Caratini et al. 1991), although it was not clear whether this was due to a naturally drier climate or to clearing of forests. According to Nagaraja, “although it is difficult to say conclusively about the effects of climate change and loss of species—projections done by Raman Sukumar, Professor and Chairman Centre for Ecological Sciences Indian Institute of Science Bangalore, using models, show that grasslands will shrink by 9 per cent. This will create an imbalance in the food chain, putting herbivores in danger.”
However, conserving plant genetic diversity cannot be in a vacuum, and hunting of animals needs to be checked, since they play a vital role in seed dispersal. In fact, a 2016 study found that defaunation is causing declines of large-seeded animal dispersed trees (Sci.Dev.Net, 2016).
Going by the findings and projections made by the Intergovernmental Panel on Climate Change (IPCC, 1990), “climate parameters are likely to change faster than the natural vegetation adaptation mechanisms”. As per these projections, the dry season length is expected to increase in south India, along with a decline in soil moisture due to higher temperatures, or evapotranspiration.
It is important to remember that the forests of the Western Ghats range from wet evergreen at 2000 m above sea level, which receive rains in the range of above 2000 mm, to montane stunted evergreen and grasslands at 1800 m, to semi-evergreen moist deciduous, dry thorn on the lower level, eastern part of the ghats. With a 2 to 3.5 degree centigrade rise in temperature, there is bound to be a shift in vegetation type (Ravindranath and Sukumar, 1998). The only way to reverse, or contain the trend, would be to increase water-use efficiency and reduce over-exploitation of resources through a time bound plan.
There is already evidence of a decline in species now, with a 1oC rise in temperatures. Further rise in temperatures would likely cause even more loss of species in the region, given the trends elsewhere (IUCN, 2016).
The draining of water from unique ecosystems like the Myristica swamps in the southernmost point of the Indian peninsula, for instance, to give way to paddy and arecanut orchards, takes its toll on many species that thrive in such an ecosystem. The Myristica swamps are home to the Myristicaceae, among other endemic species. Hence, species depletion results, as Umashankar points out.
Of late, the desire for higher productivity is driving many farmers to opt for sun-grown coffee instead of shade-grown coffee, which in Umashankar’s opinion, was “closer to native ecosystems.” Shade plantations have been known to harbour a host of bird species and hence greater avian biodiversity; this is not so with monoculture sun-grown coffee plantations.
Solutions to conserve biodiversity
Looking into the economics of ecosystems and biodiversity in the Western Ghats, experts have suggested:
- Information generation on sustainable harvest rates and creating a processing infrastructure for non-timber forest products (NTFPs) such as honey, shellac, gum;
- Sharing of the economic benefits from tourism with local communities through a formal institutional arrangement such as joint forest management;
- Developing certification schemes for the harvest of NTFPs;
- Build up the capacity of biodiversity management committees and the forest department at the range and division levels to understand the economic value of forests and to ensure adequate financial compensation to local communities.
(TEEB–India initiative, Indo-German Biodiversity Programme, GIZ India, 2016); and,
- In the matter of medicinal plants, it is important to cultivate an equitable, farmer-centric approach that takes into account the needs of local people and industry. Involving local communities in the task would be the ideal solution, and will prevent over-exploitation of resources, while ensuring that precious biodiversity is never lost to posterity.
One of the world’s top biodiversity hotspots, the Western Ghats is home to several endemic species, many of which are endangered today due to over-exploitation, deforestation and development of infrastructure. A planned approach needs to be adopted, taking local communities in confidence to conserve nature’s green gold.
Critical Ecosystem Partnership Fund. Western Ghats/Ecosystem Profile/Synopsis of Threats. Available at: http://www.cepf.net/where_we_work/regions/asia_pacific/western_ghats/ecosystem_profile/Pages/synopsis_of_threats.aspx.
Food and Agriculture Organisation of the United Nations. Impact of Cultivation and Gathering of Medicinal Plants on Biodiversity: Case Studies from India. Available at: http://www.fao.org/docrep/005/Y4586E/y4586e09.htm.
Indo-German Biodiversity Programme. Available at: http://www.indo-germanbiodiversity.com/.
IUCN, 2016. Climate Change Dramatically Disrupting Nature from Genes to Ecosystems. Available at: https://www.iucn.org/news/climate-change-dramatically-disrupting-nature-genes-ecosystems-%E2%80%93-study.
Nature Communications, 2016. Contrasting effects of defaunation on aboveground carbon storage across the global tropics.Available at:http://www.nature.com/articles/ncomms11351.
Sci Dev Net. 2016. Animals Vital for Preserving Carbon-Storing Forests. Available at: http://www.scidev.net/south-asia/conservation/news/animals-vital-for-preserving-carbon-storing-forests.html.
UNESCO. 2012. Western Ghats. Available at: http://whc.unesco.org/en/list/1342.