INTRODUCTION:

The Western Ghats or Sahyadri is a mountain range extending 1600 km along the western coast of the Indian peninsula formed by the long process of geological evolution, evolution of life on earth and evolution of human civilization¹. It covers the states of Gujarat, Maharashtra, Goa, Karnataka, Kerala and Tamil Nadu. Geological evidences indicate that this mountain top was formed due to the break-up of supercontinent of Gondwana by 255 million years ago, with the India-Madagascar fragment drifting northwards. Gondwanaland was covered by ferns and gymnosperms, and populated by frogs and reptiles, the flowering plants, with them the bees, butterflies, birds and mammals which raise them to the highest genetic diversity. When Madagascar was connected to the south-western part of India by 90 million years ago, it resulted to raise the Western-Ghats parallel to the west coast of India².

The Western Ghats involved in an important role in determining the climate and seasons in India. It blocks the rain-bearing monsoon winds flowing eastward from the Arabian Sea, bringing rainfall along the Western coast. The Government of India has established many protected areas, including two biosphere reserves, 13 national parks to restrict human access, several wildlife sanctuaries to protect specific endangered species, and many reserve forests. In the Western Ghats, the protected areas are well managed and conserved. However the protected areas are surrounded by a large number of villages and the boundaries are permeable, which has led to human interventions³. These landscapes are dominated by human intervention such as plantations, highways, human settlements, dams, hill stations, tourist resorts, railway lines, mining and quarrying. Climate change of Western Ghats is greatly influenced to the mechanism of weathering and landslides⁴. In this background, a review study is needed to find whether anthropogenic disturbances are the main cause of recent landslides in the Western Ghats of India.

MATERIALS AND METHODS:

A literature review study was conducted for understanding the factors for the landslides and floods occurred from 2018 to 2024 in the region of the Western Ghats of India. The rainfall (mm), cause and death are documented to understand the severity of climate change vulnerability. The human interventions are surveyed across the protected areas of the Western Ghats of India to understand the disturbances. The ecology of the disastrous area was studied to check whether it is present in the protected areas of the Western Ghats, India. Data collected from the above methodology is critically correlated with the natural calamity occurred from 2018-2014 to understand the geological disturbance formed in the Western Ghats of India.

Figure.1 Western Ghats of India

RESULT

Table 1. Details of Natural Calamities in the Western Ghats of India

SL	Disaster	District and State	Year	Region	Rainfall (mm)	Causes	Death
1	Mundakkai Landslide	Wayanad, Kerala	2024	WG	570	Heavy rainfall	553
2	Shirur Landslide	Uttara Kannada, Karnataka	2024	WG	503	Unscientific national highway road construction and Heavy rainfall	7
3	Kokkayar Landslide	Idukki, Kerala	2021	WG	266	Rubber plantation and Mixed vegetation	7
4	Plappally Landslide	Kottayam, Kerala	2021	WG	266	Rubber plantation	4
5	Kavali Landslide	Kottayam, Kerala	2021	WG	266	Thick mixed vegetation with rubber plantation, nutmeg, arecanut and teak	6
6	Pettimudi, Landslide	Idukki,Kerala	2020	WG	616	Heavy rainfall	70
7	Kavalappara Landslide	Malapuram, Kerala	2019	WG	189.4	Heavy rainfall and Rubber cultivation	62
8	Puthumala Landslide	Wayanad, Kerala	2019	WG	500	Heavy rainfall	17
9	Flood	Kerala	2019	WG	2309.80	Impact of global climate change	121
10	Flood	Kerala	2018	WG	2515.73	Heavy rainfall and Cloud bursting	483

WG = Western Ghat

DISCUSSION:

Biodiversity of the Western Ghats of India:

The Western Ghats of India is a mega biodiversity hotspot. It includes 30% of all the species of flora and fauna in India, most of which are endemic. The Western Ghats are covered by thick forest which forms the natural habitat for wild life and native tribal people. The threats to flora and fauna were habitat loss, overexploitation, illicit grazing, mining, illegal quarrying, poaching and introduced species. According to IUCN Red Data List 325 globally threatened species occur in the Western Ghats. The globally threatened flora and fauna in the Western Ghats are represented by 229 plant species, 31 mammal species, 15 bird species, 43 amphibian species, 5 reptile species and 1 fish species. Out of 325 globally threatened species in the Western Ghats, 129 are classified as Vulnerable, 145 as Endangered and 51 as Critically Endangered.

Causes of Climate Change and Landslides in the Western Ghats:

The Western Ghats are very prone to landslides and floods due to utmost climate change and anomalous rainfall. In the Tropical region, the upshots of climate change in rainfall will throwback as ‘Wet-gets-wetter’ or ‘warmer-gets-wetter’ pattern⁵. The reason for the rise in extreme rainfall events is due to global warming and their changes in the oceanographic conditions. The Eastern Arabian Sea and Western Indian Ocean hits a record sea surface temperature (SST) due to ocean warming and Bay of Bengal shows rise in sea surface temperature due to cyclone, fani leads to heavy rainfall events in India during the southwest monsoon and leads to catastrophic landslides⁶.

Biodiversity Loss during the Calamities in the Western Ghats:

The cause of Mundakkai Landslide is heavy rainfall. The average rainfall of Wayanad for the month of July is 600mm. In July, the daily average rainfall of Wayanad is 19.4mm and the average rainfall for 48 hours is 38.8mm. However, the average rainfall of 570 mm is reported in the two days preceding the disaster. The officials of Karnataka State Natural Disaster Monitoring Centre (KNDMC) and the Karnataka State Disaster Management Authority (KSDMA) also monitored that most of the landslides are due to road works and other infrastructure projects. The reason for Kokkayar and Plappally landslide is because of the stream flow through this area developed due to agriculture and habituation⁷. The Kavali landslide was occurred because of dense vegetation in the slopes which decreases its stability⁸. Heavy rainfall leads to Pettimudi landslide, initiated the upper slopes covered with shola forest, roads and buildings moved fastly and became the part of stream in the area⁹. The Kavalappara landslide was occurred because of torrential rainfall of 189.4 mm, instead of an average rainfall of 114.3 from August 1-7. The influence of human activity by cultivating rubber in the slopes multiplied landslide hazards in this area¹⁰. The factors for Puthumala landslide is heavy rainfall, deforestation, improper land use practices, slope modification, mining or improper drainage ¹¹. The factors of Kerala floods in 2018 are heavy rainfall and cloud bursting and 2019 is global climate change. All together in Western Ghats, the increase in rainfall intensity and human interventions appeals to landslides of multiple scales¹².

CONCLUSION:

The investigation recommends the need of significant biodiversity protection in the Western Ghats of India. Subsequently, regardless of all reasons, the common and vital feature to be addressed is climate change due to anthropogenic-related activities in the Western Ghats of India. The investigation highlights the urgent need for conservation policies to maximize the biodiversity protection and should take strict judiciary actions against human interventions in the protected areas of Western Ghats.

CONFLICT OF INTEREST:

The author has no conflicts of interest regarding this investigation.

AKNOWLEDGEMENTS:

The author would like to thank Fr. Thomas Kurian (Manager) and Fr. John P Joy (Vice-Principal) Christukula Mission English Medium Degree College, Satna, Madhya Pradesh for providing the facilities to carry out the research. The author also acknowledges Dr. K.K. Sabu, Senior Scientist, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Thiruvananthapuram, Kerala for the support and encouragement.

REFERENCES:

1. Daniels RJR. Geographical distribution patterns of amphibians in the Western Ghats of India: Journal of Biogeography.1992; 19: 521–529.

2. Myers N. Mittermeier RA. Mittermeier C.G. Da Fonseca GAB. Kent J. Biodiversity hotspots for conservation priorities: Nature. 2000; 403: 853–858.

3. Kurian, B. Hemanthakumar AS. Jacob J. Ratnam W. Choong CY. Sharma P. Shefeek S. et al Intraspecific genetic variability, differentiation and evolutionary relationships revealed through microsatellite loci in seven economically important Calamus species: Journal of Forestry Research. 2020; 31: 1899–1911.

4. Naidu S. Sajinkumar KS. Oommen T. Anuja VJ. Rinu SA. Muraleedharan C. Early warning system for shallow landslides using rainfall threshold and slope stability analysis: Geoscience Frontiers. 2018; 9(6): 1871-1882.

5. Huang P. Xie SP. Hu K. Huang G. Huang R. Patterns of the seasonal response of tropical rainfall to global warming: Nature Geoscience. 2013; 6: 357–361.

6. Singh V. Konduru RT. Srivastava TAK. Momin IM. Kumar S. Singh AK. Bisht DS. et al Predicting the rapid intensification and dynamics of pre-monsoon extremely severe cyclonic storm ‘Fani’ over the Bay of Bengal in a 12-km global model: Atmospheric Research. 2019; 247.

7. Ajin R.S. Nandakumar D. Rajaneesh A. Oommen T. Ali Y.P. Sajinkumar, K.S. The tale of three landslides in the Western Ghats, India: lessons to be learnt: Geoenvironmental Disasters. 2022; 9(1): 16.

8. Lan H. Wang D. He S. Fang Y. Chen W. Zhao P. Qi Y. Experimental study on the effects of tree planting on slope stability: Landslides.2020; 17:1021–1035.

9. Achu AL. Sabu J. Aju CD. John M. (2021). Priliminary analysis of a catastrophic land slide event on 6 th August 2020 at Pettimudi, Kerala State, India: Landslides.2021; 18:1459–1463.

10. Sarun S. Vineetha PV. Reghunath R. Sheela AM. Kumar RA. Post landslide Investigation of Shallow Landslide: A case study from the Southern Western Ghats, India: Disaster Advances. 2021; 14(7): 52-59.

11. Vasudevan N. Ramanathan K. Parvathy RS. Ramesh A. Joshy KV. Landscape Degradation: The August 2019 Puthumala Landslide in Kerala, India: Recent Advances in Sustainable Environment. Lecture Notes in Civil Engineering. Springer. 2023; 285.

12. Vijaykumar P. Abhilash S. Sreenath AV. Athira UN. Mohanakumar K. Mapes BE. Chakrapani B. et al Kerala foods in consecutive years—its association with mesoscale cloudburst and structural changes in monsoon clouds over the west coast of India: Weather and Climate Extremes. 2021; 1(33): 100339.

Received on 04.09.2024 Revised on 12.10.2024

Accepted on 08.11.2024 Published on 14.12.2024

Available online on December 05, 2024

Research J. Science and Tech. 2024; 16(4):309-312.

DOI: 10.52711/2349-2988.2024.00044

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