Impact of Landslides on the Forest Ecosystem in Wayanad District, Kerala with Special Reference to Floristic Wealth

Home , Banasura Sagar Dam, Mananthavady, Thariyode, Vellarimala, Vythiri, Wayanad district

Impact of Landslides on the Forest Ecosystem in Wayanad District, Kerala with special reference to Floristic Wealth

JNTBGRI IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA WITH SPECIAL REFERENCE TO FLORISTIC WEALTH

By Deepu Sivadas M. P. Geethakumary R. Prakashkumar

Date of Publication: June 2019

Cover: A view of Landslide affected area at Pancharakolli, Wayanad

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Citation Deepu Sivadas, Geethakumary, M. P. and Prakashkumar, R. (2019). Impact of Landslides on the Forest Ecosystems in Wayanad District, Kerala with special reference to Floristic Wealth. JNTBGRI, Thiruvananthapuram, 108 p.

Submitted to Kerala State Biodiversity Board

Submitted by The Director KSCSTE - Jawaharlal Nehru Tropical Botanic Garden and Research Institute Karimancode P.O., Palode, Thiruvananthapuram - 695 562 Kerala, INDIA PREFACE

During the Southwest monsoon of 2018 (June 1 to August 18), rainfall over Kerala has been exceptionally high, with the State receiving 2,346.6 mm against the normal of 1649.5 mm (42% above normal). There were three active spells with above normal rainfall and resulted in the worst ever floods in history since 1924. The floods and the accompanying landslides were catastrophic in terms of loss of lives, livelihoods, property and infrastructure. The damage caused to ecosystems was severe. A series of chain events starting with heavy rainfall even at the catchment areas of dams, landslides, river bursts, all major reservoirs storage was close to the full reservoir level (FRL) resulting in their opening, resulting in voluminous water flow culminated into a flash flood causing heavy erosion of river bank causing a severe impact on the vegetation in impact zone. As per the preliminary records, nearly 341 landslides were reported from 10 districts. Wayanad district experienced highest rainfall during the month of May–August with 33, 126, 160 and a 142% increase over the previous year. According to the data with the District Soil Conservation Office, Wayanad 242 land subsidence and landslip cases were reported in the district and the instances in forests were not reckoned. A landslide hazard map for the district was prepared, and it was found that 25.97% area is under a high-risk zone. The present study inventorized 60 major and 56 minor slope movements degrading over 50 hectares of forest area. A survey was done following phytosociological methods, one of its kind in post disaster impact assessment of flora and estimated a population loss for 376 angiosperm and 21 pteridophyte species. Fourteen angiosperm and five pteridophytes fall under different threat categories. In spite of the survey being short duration and not covering all seasons, it appears that no known flowering plant has become extinct however the status of seasonal plants is not known. Continued observations are needed to understand the change in vegetation dynamics of the species found in this region and the recovery dynamics. A thorough survey has to be taken up in the forests of Wayanad as fissures and scars of landslides occurred during previous years were noted in forest floors falling under high and very high risk zones. – Study Team

Contents

1. Introduction 01 1.1. Kerala Scenario 02 1.2. Rainfall over Kerala during Monsoon Season 2018 04 2. Objectives 05 3. Materials and Methods 07 3.1. Study Site 07 3.1.1. Wayanad District 07 3.1.2. Climate 08 3.1.3. Vegetation 08 3.1.4. Disaster Event 10 3.2. Methodology 10 i 3.2.1. Slope movements 10 3.2.2. Field Sampling 12 3.2.3. Period of Survey 12 3.2.4. Mapping of Landslide susceptible zones 12 4. Results 15 4.1. Rainfall 15 4.2. Slope movements 21 4.3. Baseline Floristic data 21 4.4. Impact on Flora 21 4.5. Resilient Taxa 77 4.6. Impact on livelihood 77 4.7. Immediate impact of disaster as top soil loss 77 4.8. Long-term modification in ecosystems/microhabitats 78 4.9. Impact on Biodiversity 79 5. Environmental Impact 81 5.1. Environmental Costs of Landslides 81 6. Socio economic impact 83 7. Discussion and Conclusion 85 8. Suggested interventions 87 8.1. Prioritized areas 87 8.2. Issues 87 8.3. Interventions suggested by BMC/LSG 87 8.4. Landscape and Site-specific restoration activities 88 9. Ambiguities in the study 91 10. References 93 11. Contributors & Acknowledgements 97 12. Plates 99 13. Index 107

List of Tables

3.1. Abbreviated classification of slope movements 10 3.2. Preparation of Thematic layers 13 4.1. Mean Annual and Seasonal rainfall distribution in Wayanad District 15 4.2. Location details of major landslide affected areas surveyed under Wayanad South Forest Division 22 4.3. Location details of major landslide affected areas surveyed under Wayanad North Forest Division 23 4.4. Location details of minor landslide affected areas surveyed under Wayanad South Forest Division 24 4.5. Location details of minor landslide affected areas surveyed under Wayanad South Forest Division 25 4.6. Total area under each Hazard class 26 4.7. List of Angiosperm species suffered population loss 50–59 4.8. List of Pteridophytes suffered population loss 60 ii 4.9. Conservation status of Angiosperm species suffered population loss 61–62 4.10. List of endemic species suffered the population loss 63–64 4.11. List of NWFPs suffered population loss 66–67 4.12. List of Medicinal plants suffered population loss 69–73 4.13. List of Invasive species found in the landslide affected areas 74–75 8.1. Hydrological and Mechanical mechanisms by which vegetation influences the slope 88 8.2. Suitability of plant types for different engineering functions and applications 90

List of Figures

1.1. Rainfall percentage departures from the long period averages for districts in Kerala 04 3.1. Wayanad district – Administrative boundary 07 3.2. Wayanad North Forest Division 09 3.3. Wayanad South Forest Division 09 4.1. Daily rainfall pattern of Ambalavayal region 16 4.2. Daily rainfall pattern of Kuppadi region 17 4.3. Daily rainfall pattern of Mananthavady region 18 4.4. Daily rainfall pattern of Vythiri region 19 4.5. Comparison of Average monthly rainfall in four stations 20 4.6. Comparison of total monthly rainfall in four stations 20 4.7. Spatial distribution of Rainfall across Wayanad District 21 4.8. Number of events (major) in each class of Slope movement 25 4.9. Landslide Hazard Zonation map of Wayanad 26 4.10. Percentage area falling under each Hazard class 26 4.11. Major landslide sites overlaid on Landslide Hazard Zonation Map of Wayanad 27 4.12. Minor landslide sites overlaid on Landslide Hazard Zonation Map of Wayanad 27 4.13. Landslide at Pancharakolli 28 4.14. Major Landslide at Pancharakolli 29 4.15. Landslide at Pancharakolli 30 4.16. Major landslide at Maniyankunnu 31 4.17. Agriculture land filled with debris from major landslides at Pancharakolli (Top) and Maniyankunnu (Bottom) 32 4.18. Landslide at Rassalkunnu 33 4.19. Landslide at Andikunnu (43 mile) 34 4.20. Landslide at Sooryamudi 35 4.21. Landslide at Muthumari 36 4.22. Debris runoff of Landslide at Muthumari 37 4.23. Landslide at Thacharakolli 38 4.24. Landslide at Priyadarshini 39 4.25. Fissures seen inside the Tea estate metres away from the landslide at Priyadarshini 40 4.26. Landslide at Kurisukuthi 41 4.27. Panamkuzhi Forest area 42 4.28. Landslide at Kambamala 43 4.29. Landslide at Brahmagiri 44 4.30. Landslide at Peedikapullu 45 4.31. Landslide at Peedikapullu 46 4.32. Landslide at Arikkallammottamchal 47 4.33. Landslide at Panamkunduchal 48 4.34. Landslide at Kurichiyarmala 49 4.35. Number of species in each habit class 59 1.1. Rainfall percentage departures from the long period averages for districts in Kerala 04 3.1. Wayanad district – Administrative boundary 07 3.2. Wayanad North Forest Division 09 3.3. Wayanad South Forest Division 09 4.1. Daily rainfall pattern of Ambalavayal region 16 4.2. Daily rainfall pattern of Kuppadi region 17 4.3. Daily rainfall pattern of Mananthavady region 18 4.4. Daily rainfall pattern of Vythiri region 19 4.5. Comparison of Average monthly rainfall in four stations 20 4.6. Comparison of total monthly rainfall in four stations 20 4.7. Spatial distribution of Rainfall across Wayanad District 21 4.8. Number of events (major) in each class of Slope movement 25 4.9. Landslide Hazard Zonation map of Wayanad 26 4.10. Percentage area falling under each Hazard class 26 4.11. Major landslide sites overlaid on Landslide Hazard Zonation Map of 1.1. RainfallWayanad percentage departures from the long period averages for districts in 27 4.12.Kerala Minor landslide sites overlaid on Landslide Hazard Zonation Map of 04 27 3.1. WayanadWayanad district – Administrative boundary 07 3.2.4.13 .Wayanad Landslide North at Pancharakolli Forest Division 2809 3.3.4.14 .Wayanad Major LandslideSouth Forest at Pancharakolli Division 2909 4.1.4.15 .Daily Landslide rainfall patternat Pancharakolli of Ambalavayal region 3016 4.2.4.16 .Daily Major rainfall landslide pattern at ofManiyankunnu Kuppadi region 3117 4.3.4.17 .Daily Agriculture rainfall pattern land filled of Mananthavady with debris from region major landslides at 18 Pancharakolli (Top) and Maniyankunnu (Bottom) 32 4.4. Daily rainfall pattern of Vythiri region 19 4.18. Landslide at Rassalkunnu 33 4.5. Comparison of Average monthly rainfall in four stations 20 4.6.4.19 .Comparison Landslide ofat totalAndikunnu monthly (43 rainfall mile) in four stations 3420 4.7.4.20 .Spatial Landslide distribution at Sooryamudi of Rainfall across Wayanad District 3521 4.8.4.21 .Number Landslide of events at Muthumari (major) in each class of Slope movement 3625 iii 4.9.4.22 .Landslide Debris Hazardrunoff ofZonation Landslide map at ofMuthumari Wayanad 3726 4.10.4.23 .Percentage Landslide area at fallingThacharakolli under each Hazard class 3826 4.11.4.24 .Major Landslide landslide at Priyadarshinisites overlaid on Landslide Hazard Zonation Map of Wayanad 3927 4.12.4.25 .Minor Fissures landslide seen sitesinside overlaid the Tea on estate Landslide metres Hazard away from Zonation the landslide Map of Wayanadat 27 4.13. LandslidePriyadarshini at Pancharakolli 4028 4.14.4.26 Major. Landslide Landslide at Kurisukuthi at Pancharakolli 4129 4.15.4.27 Landslide. Panamkuzhi at Pancharakolli Forest area 4230 4.16.4.28 Major. Landslide landslide at Kambamalaat Maniyankunnu 4331 4.17.4.29 Agriculture. Landslide land at Brahmagiri filled with debris from major landslides at Pancharakolli (Top) 44 4.30and. Landslide Maniyankunnu at Peedikapullu (Bottom) 4532 4.18.4.31 Landslide. Landslide at Rassalkunnu at Peedikapullu 4633 4.19.4.32 Landslide. Landslide at Andikunnu at Arikkallammottamchal (43 mile) 4734 4.20.4.33 Landslide. Landslide at Sooryamudi at Panamkunduchal 4835 4.21.4.34 Landslide. Landslide at Muthumari at Kurichiyarmala 4936 4.22.4.35 Debris. Number runoff of of species Landslide in each at Muthumarihabit class 5937 4.23. Landslide at Thacharakolli 38 4.36. Number of Pteridophytes in each conservation status and two 4.24. Landslidemorphological at Priyadarshini groups 6039 4.25.4.37. Fissures Conservation seen inside status the ofTea species estate metres away from the landslide at 62 4.38.Priyadarshini Number of Endemic species suffered population loss 6640 4.26. Landslide at Kurisukuthi 41 4.39. Number of NWFP species under different use class 67 4.27. Panamkuzhi Forest area 42 5.1. Landslide sites overlaid on Stream Network Map of Wayanad 82 4.28. Landslide at Kambamala 43 5.2. Landslide sites overlaid on Drainage Density Network Map of Wayanad 82 4.29. Landslide at Brahmagiri 44

List4.30. of PlatesLandslide at Peedikapullu 45 4.31. Landslide at Peedikapullu 46 4.32.1– 5. LandslideAngiosperm at Arikkallammottamchal species suffered population loss 10047– 104 4.33. 6. LandslidePteridophyte at Panamkunduchal species suffered population loss 10548 4.34. 7. LandslideInvasive at species Kurichiyarmala found in landslide affected areas 10649 4.35. Number of species in each habit class 59 4.36. Number of Pteridophytes in each conservation status and two morphological groups 60 4.37. Conservation status of species 62

IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

INTRODUCTION 1

Mountains play an important, albeit poorly understood, role in hydroclimatic and biogeochemical cycles that directly or indirectly sustain the livelihood of many people around the world (Schröter et al., 2005). Among the processes that continuously modify mountain-scapes, landsliding stands out because of its severe and long-lasting negative effects on natural and human-dominated ecosystems. Yet land sliding may influence ecosystems in positive ways through its effect on biodiversity and ecosystem function, raising questions about its dual role in mountain-scapes and about the nature of the feedbacks between geomorphic and biotic processes (Restrepo et al., 2009). There is mounting evidence that the frequency and magnitude of land sliding is changing in many parts of the world in response to climate change (Lateltin et al., 1997). This is not surprising, given that precipitation is one of the two external triggering mechanisms—the other being seismic activity— involved in the formation of landslides. Evidence from the past clearly indicates that 1 cycles of elevated landslide activity have been followed by cycles of low activity, and that these are correlated with climate fluctuations over a variety of timescales (González-Diez et al., 1996; Thomas, 2000). Landsliding is a complex process characterized by the down- slope movement of vegetation, soil, saprolite, and rock under the influence of gravity. In dry environments, mass movements often involve rocks, whereas in humid environments they involve vegetation, soil, and deeply weathered bedrock. We focus mostly on humid environments because there the influence of biotic processes is most visible, and because these environments are the best studied (Restrepo et al., 2009). The spatial and temporal variability of landslides, whether at the individual, population, or assemblage level, is likely to influence ecosystem function and diversity in profound ways. First, landsliding, unlike other disturbances (Pickett & White, 1985), transforms substrates in complex ways through the sudden down- slope transport of vegetation, soil, and saprolite (Furian et al., 1999; Geertsema & Pojar,2007). Second, landsliding results in highly heterogeneous landscapes in which landslide size and proximity may influence the movement of organisms and ecosystem development (Hupp, 1983), as has been documented for other disturbances (Paine & Levin, 1981). Third, ecosystems reorganize on these quasi-primary substrates, and this entails the rejuvenation of soils and the colonization of landslides by an unknown array of organisms (Walker et al., 1996, Wilcke et al., 2003). Ecosystems reorganize on landslides over time. Studies documenting changes in species composition and abundance over short timescales (< 5 years) show that species trajectories, and therefore some assemblage- level attributes, may vary widely, and sometimes in unpredictable ways (Dale et al., 2005; Velázquez & Gómez-Sal, 2007). In India, about 0.42 million sq. km or 12.6% of land area, excluding snow covered area, is prone to landslide hazard. Out of this, 0.18 million sq. km falls in North East Himalaya, including Darjeeling and Sikkim Himalaya; 0.14 million sq. km falls in North West Himalaya (Uttarakhand, Himachal Pradesh and Jammu & Kashmir); 0.09 million sq. km in Western Ghats and Konkan hills (Tamil Nadu, Kerala, Karnataka, Goa and Maharashtra) and 0.01 million sq. km in Eastern Ghats of Aruku area in Andhra Pradesh. The landslide-prone Himalayan terrain also belongs to the maximum earthquake-prone zones (Zone-IV and V; BIS 2002) where earthquakes of Modified Mercalli intensity VIII to IX can occur, and thus, are also prone to earthquake-triggered landslides (GSI, 2019). Landslides are spread over 22 States and 2 Union Territories including J&K, Himachal, Uttarakhand, Arunachal, Assam, Meghalaya, Mizoram, Manipur, Nagaland, Sikkim, Tripura, Kerala, Karnataka, Tamil INTRODUCTION

Nadu, Andhra Pradesh, Goa, Maharashtra, Madhya Pradesh, Chhattisgarh, Andaman & Nicobar and Puducherry. The most sensitive areas are Himalayan belt, Nilgiris, Western and Eastern Ghats. Landslides constitute a serious hazard that causes substantial human and financial losses in the country. It is estimated that on an average about 500 lives are lost and costs approximately Rs.300 crores INR annually (Parkash, 2012). 1.1. Kerala Scenario

Kerala is highly vulnerable to natural disasters and the changing climatic dynamics given its topographic position with the Arabian Sea along its West side forming about 590 km of sea coast and with a steep gradient along the slopes of the Western Ghats. The Kerala State Disaster Management Plan (KSDMA, 2016) identifies 39 hazards categorised as naturally triggered hazards (natural hazards) and anthropogenic triggered hazards (anthropogenic hazards). Kerala is also one of the most densely populated Indian states (860 persons per square kilometres) making it more vulnerable to damages and losses on account of disasters (PDNA, 2018). Floods are the most common of natural hazard in the state. Nearly 14.5% of the state’s land area is prone to floods, and the proportion is as high as 50% for certain districts. Landslides are a major hazard along the Western Ghats in Wayanad, Kozhikode, Idukki, and Kottayam districts. Seasonal drought-like conditions 2 are also common during the summer months. Kerala experienced 66 drought years between 1881 and 2000 (KSDMA, 2016), dry rivers and lowering water tables in summer have led to water scarcity both in urban and rural areas. Other major natural hazards are lightning, forest fires, soil piping, coastal erosion, and high wind speed. The state also lies in seismic zone III. The state has a complex topography with mountains, valleys, ridges and scarps. It is drained by 44 rivers of which 3 are east flowing. A physiographic classification, identified mainly in terms of broad geomorphic surfaces and altitudinal characteristics, is also used in the parlance of geographers (CESS, 1984). It has five physiographic zones, namely, high ranges with elevation above 600 m, foothill zone between 300 to 600 m, upland regions between 100–300 m, midland between 20–100 m and coastal areas and low land below an altitude of 20 m. There are 44 rivers in Kerala, which are over 160 km in length; three are East flowing as tributaries to the Kaveri while all others are West flowing. The climate of Kerala is tropical maritime and monsoon in character. Temperatures and humidity are high throughout the year and rainfall is abundant with rain for nearly ten months. Mountain barriers, altitude, latitude, land water masses, vegetation, soil type, ocean currents etc. are major factors of climate control (Niyas et al., 2017). The annual rainfall in Kerala varies from 380 cm over extreme northern parts to about 180 cm in the southern parts. The Southwest monsoon is the principle rainy season when the state receives about 75% of the annual rainfall. Southwest monsoon rainfall as a percentage of the annual decreases from north to south from 85% in the north to 54% in the south. Northeast monsoon rainfall as a percentage of the annual increase from north to south from 7% in the north to 25% in the south (Mini et al., 2017). Though the state has been blessed with rich natural resources such as forest, biodiversity, water resources and mineral resources, deterioration is felt in recent years which evidently had far-reaching consequences. The change in rainfall distribution and frequency and, in basin ecology altered the perennial river of Kerala to non-perennial. Kerala has experienced unprecedented heat wave condition and wide variations in the rainfall pattern recently. Heat wave conditions to a greater extent were not at all familiar to Keralites until the pre-monsoon season of 2015. It is reported that the frequency and duration of weak rainfall periods and drought conditions are gradually increasing in the state. This pattern in negatively influencing our agriculture production, electricity generation, public health scenario, marine resources, and so on. Extreme weather conditions like heat waves and cyclones are becoming frequent (Chackacherry et al., 2017). Recent studies (Niyas et al., 2017) had showed trends in the resident temperatures shifting towards higher sides, which confirms the effect of global warming irrespective of urban effect. The analysis based on data IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Changing Climate Scenario in India

In 1997, K. J. Henessey, Scientist at the Australia-based Commonwealth Scientific and Industrial Research Organization, used mathematical calculations and empirical evidence to predict climate warming would cause intense rainfall and increase risk of floods. It proved true for India. The highest rainfall pockets in India are generally those receiving orographically induced rainfall caused by forced moist air ascent over the slopes during the active monsoon situations. Western Ghats and North-East India receive such type of heavy rainfall. Along the monsoon trough region also, more than 50 cm rainfall has been recorded in 1-day duration. The west coast projections indicate that in the 2030’s the annual rainfall will vary from 935± 185.33 mm to 1794±247.1 mm. The trend of rainfall in the 2030’s is showing an increase with respect to the 1970s in this region as well. The increase in rainfall is by 6 to 8%, an increase that is ranging from 69 to 109 mm. Though June, July and August show an average increase of 8 mm rainfall in the 2030’s with respect to 1970s, however, the winter rainfall is projected to decrease on an average by 19 mm during the period January and February in the 2030’s with reference to 1970s. The period March, April and May also show a decrease in rainfall with respect to 1970s. Any particular day, receiving rainfall greater than 2.5 mm, is considered as a rainy day. It is predicted a decrease in the intensity of rainy days over the Western Ghats, i.e., a decrease in the number of rainy days 3 by 5 to 10 days with respect to 1970s. The intensity of rainfall is likely to increase by 1–2 mm/day. The global rainfall data for over the last century shows an alarming trend: “The number of rainy days are decreasing while intense rainfall events of 10–15 cm/day are increasing. This means that more amount of water is pouring down in lesser time. For example, globally, 50 percent of annual precipitation (rain, snow and ice) is received in just 11 days. As per IMD this trend is visible in India as well, with high rainfall events (more than 10cm/day) increasing and low rainfall events (less than 5cm/day) falling. The pattern is similar in the data of decades of the past century. In recent decades, extremely heavy rainfall events have risen. Northwestern and Peninsular India have been particularly vulnerable. When such heavy rainfall events are stretched over a few days and combined with certain geographies, natural degradation and bad water management, they can result in catastrophes such as the Kerala floods in August 2018.

Number of rainy days as simulated by PRECIS for baseline simulation (upper panel)

The change in the frequency of rainy days in the 2030s (lower panel)

Source: Climate Change and India a 4 × 4 assessment and IMD INTRODUCTION

from 1969 to 2012 showed significant changes in trends in all the stations even during monsoon season. Guhathakurta and Rajeevan (2008) have reported that the extreme southern parts of the country i.e., Kerala and Tamilnadu is getting more dry days. Sudevan et al. (2016) had also suggested variability in rainfall intensity and rainy days due to climate change and are well documented for the Indian region. Studies (Abilash & Krishnakumar, 2017) predict that the weather hazards associated with pre-monsoon thunder clouds is likely to increase, and the frequency and severity of lightning strikes, flash floods, cloud bursts and microburst may increase in future over Kerala.

1.2. Rainfall over Kerala during Monsoon Season 2018

Rainfall over Kerala during southwest monsoon season 2018 (1 June to 19 August 2018) has been exceptionally high. Kerala during this period received 2346.6 mm against the normal of 1649.5 mm (above normal by 42%). The spatial distribution of district-wise seasonal rainfall indicates that highest excess rainfall is recorded over Idukki District (92% above normal) followed by Palakkad (72% above normal). The rainfall over Kerala during June, July and August (1–19 August) has been 15%, 18% and 164% above normal respectively (Source: IMD release dated 19 August 2019).

Figure 1.1. Rainfall percentage departures from the long period averages for Districts in Kerala IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

OBJECTIVES 2

Survey and documentation of the extend of forest cover loss and species loss.

To identify plant species which should be included in species recovery programmes.

Mapping the landslide susceptibility zones and prepare the landslide susceptible zone map of the district. Descend strategies for rehabilitation of landslide affected areas. INTRODUCTION

6 IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

MATERIALS AND METHODS 3

3.1. Study Site

3.1.1. Wayanad District The district is in the north-east of Kerala state, formed on 1 November 1980 as the 12th district in Kerala by including areas from erstwhile Kozhikode and Kannur districts with a total area of 2131 km2 i.e., 5.48 percent of total geographical area of the State (Fig. 3.1). The area lies between North latitude 110 26’ to 120 00’ and East longitude 750 75’ to 760 56’. Altitude varies from 700 to 2100 metres above mean sea level. The district is bordered by Karnataka to north and north-east, Tamil Nadu to south-east, Malappuram to south, Kozhikode to south-west and Kannur to north-west. It is a mid-level plateau, standing on the southern tip of the Deccan plateau and includes part of the Western Ghats. Forest covers quite a large area of the district, but the continued and indiscriminate exploitation of the natural resources point towards an imminent environmental crisis (Münster & Münster, 2012). 7

Figure 3.1. Wayanad district - Administrative boundary

It can divide the district in two parts based on its topography, the southwestern part and the northeastern part. Along the southwestern corner of Wayanad, there is a chain of isolated high ridges—Chembra– Vellarimala mountain range like the Nilgiris in ecological conditions. The northeastern corner of Wayanad rises to a hill range called the Brahmagiris, which forms the western and southwestern border of the Coorg plateau. From the highest altitude of the Western Ghats on the southwest and western border of the district, the plateau of Wayanad slopes down towards northeast and eastward. Wayanad comprise 2 Sub Micro MATERIALS AND METHODS

regions viz, Wayanad Forested Hills and Wayanad plateau. The district has rich water resources. There are east flowing and west flowing rivers in the region. Kabani is a main river of the district, one of the East flowing rivers of Kerala. Three tributaries of Kabani river are Panamaram, Mananthavady and Tirunelli with a total drainage area of 1974 km2. Other important rivers are Mahe and the Chaliyar. The Mahe river (Mayyazhipuzha) originates from the western slopes of the dense forests of Mananthavady taluk. The Chaliyar or Beypore river originates from the Elembileri Hills of Sulthanbathery taluk. All these rivulets help form a rich water resource and a distinct landscape for the district. We can broadly divide the district into four geological domains viz. the Peninsular Gneissic Complex in the North and central part, the Migmatite Complex in the south-central part, the Charnockite group in the south and the Wayanad group in the North. Based on topographic features, it can divide the area into different physiographic zones like high ranges with rugged moderate topography, Intermountain valley and flood plains. High ranges with rugged topography include hill ranges in the west, north west and southwestern part of Wayanad district and elevation ranges from 1400 to 2100 above MSL. This area occupies dense mixed jungles and having rugged topography with steps slopes and narrow valleys. Hill–ranges along the eastern part and isolated hills come under high ranges with moderately rugged topography. The altitudes of physiographic zones range between 1000 and 1400 cm with a moderate slope. The land form units 8 identified in Wayanad are alluvial plains, valley fill, flood plains, valley fill, linear ridge hill crust, sloping terrains, rocky slope and hilly terrain. 3.1.2. Climate Wayanad has a salubrious climate. The mean average rainfall in this district is 2608 mm. Lakkidi, Vythiri and Meppadi are the high rainfall areas in Wayanad. Annual rain fall in these high rainfall areas ranges from 3000 to 4000 mm. The Northern hills of Wayanad are known for the high velocity winds it receives during the Southwest Monsoon (which falls during June -September) and dry winds common during March-April. One among the wettest locations in the entire country, it has a rather cool climate throughout the year. The district records a mean average of 2322 mm rainfall, although areas like Vythiri averages between 3000 and 4000 mm of rainfall. The temperature stays between 18 to 29 degree Celsius, though the rate of humidity is high, which goes even up to 95 percent during the southwest monsoon period. Residents classify December–February as the coldest months while March to May are the hot months.

3.1.3. Vegetation Wayanad district converges different vegetation types along the windward and leeward side of the Western Ghats and dominated by Malabar floristic elements and the total area under forests in Wayanad is 787 km2. By following Chandrasekharan (1962) and revised classification by Champion and Seth (1968), the natural vegetation falls into the following types: 1. West-coast tropical evergreen forests 2. West-coast tropical semi-evergreen forests 3. Southern moist-mixed deciduous forests 4. Southern dry-mixed deciduous forests 5. Southern montane wet-temperate forests 6. Southern wet-montane grasslands Administratively, the forest area in the district is divided into Wayanad Wildlife Sanctuary (Sulthan Bathery, Muthanga, Kurichiad and Tholpetty Ranges) with an area of 344.44 km2 and other reserve forests. The reserve forest of the district is under two administrative divisions namely Wayanad north and Wayanad south divisions. North division constitutes Mananthavady, Periya and Begur ranges, which is dominated IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 3.2. Wayanad North Forest Division

Figure 3.3. Wayanad South Forest Division MATERIALS AND METHODS

by evergreen and moist deciduous forests. South division forms Kalpetta, Meppady and Chedeleth ranges, which is also dominated by evergreen and moist deciduous forests. In addition, one special range for managing the coffee plantations situated at Cheeyambam and Pambra is also functioning under south division. The North Division is having 214.9407 km2 comprising 134.0240 km2 of reserve forest (including 3,632.974 ha. of plantations) and 65.8527 km2 of vested + EFL area. The South Wayanad Division is having an area of 347.6640 Km2 of forests, including 66.1381 km2 reserve forests and 274.6810 km2 of vested + EFL area (KFD, 2016). The natural forests of this tract fall under three broad types vide “Revised classification of forest types of India” by Champion and Seth (KFD Management Action Plan): The West Coast Tropical Evergreen Forest–IA/C4, West Coast Semi Evergreen Forest–2A/C2 and Southern Tropical Moist Deciduous Forest– 3B/CIC. According to the Western Ghats Ecology Expert Panel (WGEEP) report (Gadgil et al., 2011), the mountain pass and its environs comes under ESZ I. About 2034 species of Angiosperms under 903 genera are reported to be occurring in this district. 29% of the species are endemic to this region and 138 are coming under different threat categories (Ratheesh Narayanan, 2009). The district is also rich in Pteridophyte diversity with a total of 163 species of which 19 are endemic and 27 are threatened (Mini, 2015).

10 3.1.4. Disaster Event Between June 1 and August 18, 2018, as every part in Kerala, Wayanad experienced the worst ever floods in its history since 1924, with excess than normal average rainfall. The torrential rains triggered several landslides and forced the release of excess water from dams, aggravating the flood impact. The catchment area of the Banasura Sagar dam, 20 km northwest of district headquarters Kalpetta, received the highest rainfall of 4,824 mm, causing floods. As per the records of Wayanad District Soil Conservation Office, there were 47 landslides, 155 landslips and 45 instances of land subsidence from June 1 to August 30. However the landslides/landslips occured in the forest areas are not inventorized. Only the major landslides close to inhabited areas were properly documented.

3.2. Methodology 3.2.1. Slope movements The criteria used in the classification of landslides presented here follow Varnes (1978) with modifications by Cruden and Varnes (1996) in emphasizing the type of movement and the type of material. Any landslide can be classified and described by two nouns: the first describes the material and the second describes the type of movement, as shown in Table 3.1 (e.g., rock fall, debris flow).

Table 3.1. Abbreviated classification of slope movements

TYPE OF TYPE OF MATERIAL MOVEMENT BEDROCK ENGINEERING SOILS PREDOMINANTLY PREDOMINANTLY COARSE FINE Fall Rock fall Debris fall Earth fall Topple Rock topple Debris topple Earth topple Slide Rock slide Debris slide Earth slide Spread Rock spread Debris spread Earth spread Flow Rock flow Debris flow Earth flow Complex Combination of two or more principal types of movement

Shortfall Validating 3d map 100% accuracy, indebth 1 m resolution, Landuse planning and DEM in 1m IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Classification of Slope movements

http://www.ukgeohazards.info/pages/eng_geol/landslide_geohazard/eng_geol_landslides_classification.htm MATERIALS AND METHODS

3.2.2. Field Sampling Information on the landslide instances in forest areas were sourced through discussion with forest personals, supplemented by personal observations. The species richness of a community of animals or plants—that is, the number of species present within this community—is a basic measure of its biodiversity (Huston, 1994). Estimating the species richness of a biological community located in some specified region, often relies on quadrat sampling (Krebs, 1989). Counts of plants or animals on areas of known size are among the oldest techniques in ecology. The density, understood as the number of individuals of each species and of all other species occurring per unit area in the studied forest population, reported in absolute

quantities as the absolute density (Dabs), according to Curtis and McIntosh (1950), and in relative form

as relative density (Drel), is obtained by effective counts of individuals in a continuous space and reported as a percentage (Finol, 1971). If species are evaluated based on their density, called abundance by some researchers, the species are ranked as very rare, rare, occasional, abundant and very abundant, and these ranks form relevant information to characterize the composition of the forest population (Förster, 1973; Longhi, 1980). The value of importance (IVI), proposed by Curtis and McIntosh (1950) and used by Cottam and Curtis (1956) and by Förster (1973), is considered a relevant estimator to order the importance of each species in the phytocoenosis. Since there is no information on the spatial distribution of the species in the study areas, phytosociological 12 techniques were used and for which species with GBH ≥ 10 cm were enumerated and parameters such as GBH, height, the number of individuals, to understand the relative abundance, relative frequency, species richness, IVI etc. of the species in a community. Quadrats were used to survey the species loss in areas were the size of the slope movement is greater than 500 m2, by using a 20 × 20 m. quadrat for counting trees and 5 × 5 m. for shrubs and herbs. A 50 m buffer was laid around the landslide scar for conducting the quadrat survey. In cases where the primary deposition area also falls inside the forest, the buffer is laid wholly including the scar and deposition site. Transect sampling was carried out in events where the area is less than 500 m2. To be efficiently implemented hierarchical parametric approaches requires some substantial prior information and cannot be used in little-known regions. Here, frequency and density is used to quantify and describe the distribution of a species in a community. The proportion of plots that contain a plant of interest give an indication of how widely distributed that plant species is across that landscape. Distribution pattern of each species were calculated and analysed using Whiteford Index (Whiteford, 1949). Percentage frequency, density and Whiteford Index are used as determinants for understanding the species loss in a given area with theoretical considerations assuming that the individuals of all the species are distributed at random. On the assumption of the random distribution of individuals of species, the probability of not finding an individual (q) is q = e–m, where m is the mean density; and the probability of finding one or more individuals in a quadrat (p) is p = 1–q = 1– e–m (Singh & Das, 1939). The species with a percentage frequency greater than 90 and p ≥ 0.9 are considered as succumbing population loss. At places possible fallen trees were counted from the debris deposited downstream. 3.2.3. Period of Survey The rapid assessment was conducted during a three-month period from December 2018 to March 2019.

3.2.4. Mapping of Landslide susceptible zones For explicating the landslide susceptibility map of the district, 14 thematic layers prepared (Table 3.2.). For finding the landslide hazard zones we give each thematic layer a rank depending upon its influential in determining the landslides happening in the study area. Ten thematic layers add its corresponding factors and given proper weightage in correlation with the landslides. Raster calculator method is applied in finding out the landslides hazard zone and we divide the study area into 4 zones—very–low, low, moderate, high and very–high. Garmin Oregon 550 GPS is used for collecting the field data. The software tools used IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA for the purpose are ERDAS 14.0 and ArcGIS 10.5.

Table 3.2. Preparation of Thematic layers

Sl. No. Layer Method Source 1 Soil Digitization NBSS & LUP 2. Geology Digitization GSI 2005 3. Streams Digitization Toposheets 4. Drainage density Line density (Spatial Analyst) Toposheet 5. Landform/ Digitization KSLUB (kslub.in) Geomorphology 6. Slope Spatial Analyst SRTM DEM 7. Rainfall Distribution Interpolation (IDW) CHIRPS 8. Lineament Density Line Density DEM 9. Topographic Genness Algorithm DEM Wetness Index 10. Topographic Genness Algorithm DEM Position Index 11. Roughness Geomorphic & Gradient Matric DEM 13 Tool Box (Evans, 2009) 12. Site Exposure Index Geomorphic & Gradient Matric DEM Tool Box (Evans, 2009) 13. Curvature Genness Algorithm DEM 14. Dissection Index Genness Algorithm DEM

Shortfall Validating 3d map 100% accuracy, indebth 1 m resolution, Landuse planning and DEM in 1m MATERIALS AND METHODS

14 IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

RESULTS 4

4.1. Rainfall From 1 June 2018 to 19 August 2018, Kerala experienced unusually high rainfall (around 42 percent above normal). Initially, with 15 percent and 18 percent above normal precipitation, the months of June and July were somewhat wetter than usual. The state experienced downpours of 164 percent above normal during the first three weeks of August. According to the India Meteorological Department (IMD), the rainfall depths recorded during August 15–17 were found to be analogous to the massive storm that occurred in 1924. For a better understanding of the scenario in the Wayanad District, rainfall data from 4 stations of IMD viz., Kalpetta, Mananthavady, Kuppady and Ambalavayal during the months of May, June, July, August, and September for the three consecutive years—2016, 2017 and 2018 were compared. The total rainfall received during the months of May–August during 2016, 2017 and 2018 are 5,438.9 mm, 5,665.9 mm and 12,897.2 15 mm respectively. There has been an increase of 128 % in the rainfall during 2018 compared with 2017 and 137 % compared to 2016 (Figs 4.1–4.6).

Although the Wayanad district’s average annual rainfall is 3253 mm, its space and time distribution shows large variations. The estimated annual average rainfall in Ambalavayal, Manathavady and Vythiri is approximately 1945.5 mm, 2513.9 mm and 4176.9 mm. The south-west monsoon is more prominent in the Wayanad than the northeast monsoon. The contribution of Southwest (SW) monsoon rainfall in Ambalavayal, Mananthavady and Vythiri is approximately 64.8%, 80.9% and 81% of the average annual rainfall. While the Northeast (NE) monsoon’s contribution to Ambalavayal, Mananthavady and Vythiri is around 17.3%, 9.7% and 9.8%. The long–term pattern of six precipitation variables for three stations in the district of Wayanad evaluated using a linear regression method shows that annual, southwestern, winter rainfall and rainy days reveal a declining trend for all three stations. For stations at Ambalavayal, Mananthavady and Vythiri, the decreasing trend for rainy days corresponds to 19, 12, and 32 days over the total period analysed*. Table 4.1. Mean Annual and Seasonal rainfall distribution in Wayanad District Mean South-West North-East Winter Summer Rain gauge Annual Monsoon Monsoon Rainfall Rainfall Station/ Rainfall (mm, % of (mm, % of (mm, % of (mm, % of parameters (mm) annual) annual) annual) annual) 1265.1 336.3 29.7 318.3 Ambalavayal 1949.4 64.8% 17.3% 1.5% 16.4% 2027.1 249.9 12.4 223.2 Mananthavady 2512.6 80.9% 9.7% 0.5% 8.9% 3356.7 436.9 16.8 335.8 Vythiri 4146.1 81.0% 9.8% 1.1% 8.1% *The observations were based on the trend analysis of the daily rainfall recorded at Vythiri (1901-2011) and Mananthavady (1950-2011) and Ambalavayal (1980-2011)

Shortfall Validating 3d map 100% accuracy, indebth 1 m resolution, Landuse planning and DEM in 1m 80.0

RESULTS 70.0 60.0 80.0 50.0 80.070.0 Figure 4.1. Daily rainfall pattern of Ambalavayal region 40.0 70.060.0

60.050.0 30.0 50.0 40.0 20.0 40.0 30.0 10.0 30.0 20.0 20.0 0.0 10.0 10.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 0.0 0.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 May-16 May-17 May-18 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 May-16 May-17 May-18 May-16 May-17 May-18 90.0 90.0 90.0 80.0 80.0 80.0 70.0 70.0 70.0 60.0 60.0 60.0 50.0 50.0 50.0 40.0 40.0 40.0 30.0 30.0 20.0 10.0 20.0 0.00.0 10.0 16 11 2 2 3 3 4 4 5 5 6 6 7 78 98 101112131415161718192021222324252627282930 9 101112131415161718192021222324252627282930 0.0 Jun-16Jun-16 Jun-17Jun-17 Jun-18Jun-18 1 2 3 4 5 6 7 8 9 101112131415161718192021222324252627282930 90.0 Jun-16 Jun-17 Jun-18 80.0 70.0 70.0 90.0 60.0 80.0 50.0 40.0 70.0 30.0 30.0 60.0 20.0 20.0 50.0 10.0 10.0140.0 0.0 40.0 0.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 120.0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223242526272829303130.0 Jul-16 Jul-17 Jul-18 Jul-16 Jul-17 Jul-18 100.0 20.0 140.010.0 80.0 120.0 0.0 60.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 100.0 40.0 Jul-16 Jul-17 Jul-18 80.0 20.0 60.0 0.0 40.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031

Aug-16 Aug-17 Aug-1820.0

0.0 100.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 90.0 Aug-16 Aug-17 Aug-18 80.0 70.0 100.0 60.0 90.0 50.0 80.0 40.0 70.0 60.0 30.0 50.0 20.0 40.0 10.0 30.0 0.0 20.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 10.0 Unit: mm Sep-16 Sep-17 Sep-18 0.0 Source: India Meteorological Department 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Sep-16 Sep-17 Sep-18

40.0

35.0

30.0 IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA 25.0

20.0 40.0

15.040.0 35.0 Figure 4.2. Daily rainfall pattern of Kuppady region

10.035.0 30.0

30.05.0 25.0

25.00.0 20.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 20.0 15.0 May-16 May-17 May-18 15.0 10.0 100.010.0 5.0 90.05.0 0.0 80.0 0.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 70.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 60.0 May-16 May-17 May-18 May-16 May-17 May-18 50.0 100.0 100.040.0 90.0 30.090.0 80.0 20.080.0 70.0 10.070.0 60.0 60.00.0 50.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 2150.0 22 23 24 25 26 27 28 29 30 40.0 Jun-16 Jun-17 Jun-1840.0 30.0 30.0 17 80.0 20.0 20.0 70.010.0 10.0

60.00.0 0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 231 24 2 25 3 26 4 27 5 28 6 29 7 830 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 50.0 Jun-16 Jun-17 Jun-18 Jun-16 Jun-17 Jun-18 40.0 80.0 30.0 80.0 70.0 20.0140.0 70.0 60.0 10.0 60.0 120.0 50.0 0.0 50.0 100.040.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 40.0 30.080.0 Jul-16 Jul-17 Jul-18 30.0 20.0 140.0 60.0 20.0 10.0 120.0 40.0 10.0 0.0 100.0 20.0 1 2 3 4 5 6 7 8 9 101112131415161718192021222324252627282930310.0 Jul-16 Jul-17 Jul-1880.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 0.0 Jul-16 Jul-17 Jul-18 1 2 3 4 5 6 7 8 9 1011121314151617181920212223242526272829303160.0

Aug-16 Aug-17 40.0Aug-18

80.0 20.0

70.0 0.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 60.0 Aug-16 Aug-17 Aug-18 50.0

40.0 80.0 70.0 30.0 60.0 20.0 50.0 10.0 40.0 0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1930.0 20 21 22 23 24 25 26 27 28 29 30 Unit: mm Sep-16 Sep-17 20.0Sep-18 Source: India Meteorological Department

10.0

0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Sep-16 Sep-17 Sep-18

70.0

60.0

RESULTS50.0 70.0 40.0 60.0 30.0 70.0 Figure 4.3. Daily rainfall pattern of Mananthavady region 50.0 60.020.0 40.0 50.010.0 30.0 40.00.0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223242526272829303120.0 30.0 May-16 May-17 May-18 20.0 10.0 300.0 10.0 0.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 250.00.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 May-16 May-17 May-18

200.0 May-16 May-17 May-18 300.0

300.0150.0 250.0 250.0100.0 200.0 200.050.0 150.0 150.0 0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22100.0 23 24 25 26 27 28 29 30 100.0 Jun-16 Jun-17 Jun-18 18 50.0 50.0 140.0 0.0 0.0 120.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 271 28 2 29 330 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Jun-16 Jun-17 Jun-18 Jun-16 Jun-17 Jun-18 100.0

140.080.0 140.0

120.0 60.0 120.0 100.0 350.040.0 100.0 80.0 300.020.0 80.0 60.0 250.00.0 60.0 40.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 200.0 40.0 20.0 Jul-16 Jul-17 Jul-18 150.0 350.0 20.0 0.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 100.0 300.0 0.0 Jul-16 Jul-17 Jul-18 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 50.0 250.0 Jul-16 Jul-17 Jul-18 0.0 200.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 150.0 Aug-16 Aug-17 Aug-18

100.0 90.0 80.0 50.0

70.0 0.0 60.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 50.0 Aug-16 Aug-17 Aug-18 40.0 90.0 30.0 80.0 20.0 70.0 10.0 60.0 0.0 50.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Unit: mm 40.0 Sep-16 Sep-17 Sep-18 Source: India Meteorological Department 30.0 20.0 10.0 0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Sep-16 Sep-17 Sep-18

45.0 40.0 35.0 30.0 IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA 25.0

20.0 45.0 45.0 Figure 4.4. Daily rainfall pattern of Vythiri region 15.0 40.0 40.0 10.0 35.0 35.0 5.0 30.0 30.0 0.0 25.0 25.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 20.0 20.0 May-16 May-17 May-18 15.0 15.0 180.0 10.0 10.0 160.0 5.0 5.0 140.0 0.0 0.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 120.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 100.0 May-16 May-17 May-18 May-16 May-17 May-18 80.0 180.0 180.060.0 160.0 160.040.0 140.0 140.020.0 120.0 120.00.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20100.0 21 22 23 24 25 26 27 28 29 30 100.0 Jun-16 Jun-17 Jun-1880.0 80.0 19 60.0 180.060.0 40.0 160.040.0 20.0 140.020.0 0.0 120.00.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 100.0 Jun-16 Jun-17 Jun-18 80.0 Jun-16 Jun-17 Jun-18 220.0 60.0 180.0 180.0200.0 40.0 160.0 160.0180.0 160.020.0 140.0 140.0 140.00.0 120.0 120.0 120.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031100.0 100.0 100.0 Jul-16 Jul-17 Jul-1880.0 80.0 80.0 220.060.0 60.0 200.0 40.0 40.0 180.0 20.0 20.0 160.0 0.0 0.0 140.0 0.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031 1 2 3 4 5 6 7 8 8 9 9 10111213141516171819202122232425262728293031 10111213141516171819202122232425262728293031120.0 Jul-16 Jul-17 Jul-18 Aug-16Jul-16 Aug-17Jul-17 Jul-18Aug-18100.0 80.0 120.0 60.0 40.0 100.0 20.0 0.0 80.0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031

Aug-16 Aug-17 Aug-18 60.0

120.0 40.0

100.0 20.0

80.0 0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 60.0 Unit: mm Sep-16 Sep-17 Sep-18 Source: India Meteorological Department 40.0

20.0

0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Sep-16 Sep-17 Sep-18

RESULTS

60 60

50 50

40 40

30 30

20 20

10 10

0 0 Jul-16 Jul-17 Jul-18 Jun-16 Jun-17 Jun-18 Sep-16 Sep-17 Sep-18 Aug-16 Aug-17 Aug-18 May-16 May-17 May-18 Jul-16 Jul-17 Jul-18 Jun-16 Jun-17 Jun-18 Sep-16 Sep-17 Sep-18 Aug-16 Aug-17 Aug-18 May-16 MayMay-17 May-18 June July August September May June July August September Ambalavayal Kuppady Mananthavady Vythiri 20 Ambalavayal Kuppady Mananthavady Vythiri

Figure 4.5. Comparison of Average monthly rainfall in four stations

1600.0 1600.0 1400.0 1400.0 1200.0 1200.0 1000.0 1000.0 800.0 800.0 600.0 600.0 400.0 400.0 200.0 200.0 0.0 0.0 Jul-16 Jul-17 Jul-18 Jun-16 Jun-17 Jun-18 Sep-16 Sep-17 Sep-18 Aug-16 Aug-17 Aug-18 May-16 May-17 May-18 Jul-16 Jul-17 Jul-18 Jun-16 Jun-17 Jun-18 Sep-16 Sep-17 Sep-18 Aug-16 Aug-17 Aug-18 May-16 May-17 May-18 May June July August September May June July August September Ambalavayal Kuppady Mananthavady Vythiri Ambalavayal Kuppady Mananthavady Vythiri Figure 4.6. Comparison of total monthly rainfall in four stations

In the month of May 2018, total rainfall increased by 33% and 92% respectively from 2017 and 2016; in the month of June, total rainfall increased by 126% and 59% respectively from 2017 and 2016; in the month of July, total rainfall increased by 160% from the previous two years; in the month of August there has been an increase in total rainfall of 142 % and 263 % from 2017 and 2016 respectively. The above observations on rainfall increases are based on data from only four stations. However, there is sufficient possibility of isolated rainfall scenario based on previous occurrence data and the district topography that is not accurately reflected in the data available from the IMD stations. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

21 Figure 4.7. Spatial distribution of Rainfall across Wayanad District

4.2. Slope movements The study team had surveyed the forest areas in Wayanad district and was able to record a total of 60 major slope movement instances and 56 minor instances. In this report those instances where the area affected by the event is more than 500 m2 is included as major (Table 4.2 & 4.3, Fig. 4.8) and those below as minor, falling under slope movement type: Earth fall (Table 4.4 & 4.5). Landslides/slips had occurred mostly in the Wayanad North and South Forest divisions and there are no such instances under the forest areas of Wayanad Wildlife Sanctuary. As part of the objective of the study, landslides susceptible zone map of Wayanad district was prepared and the present events were overlaid over the map for ready reference (Fig. 4.11 & 4.12). 4.3. Baseline Floristic data Even though the district is recognized for its species richness, no recorded data is available on the temporal and spatial distribution of flowering plants apart from the work by Ratheesh Narayanan (2009) on the angiosperm flora and Mini (2015) on the pteridophyte diversity of the district. Some ground data is available with TBGRI, being the coordinating centre for the Nilgiri Biosphere Reserve programme had conducted surveys on the regions coming under the Biosphere. All these were consulted and along with which inputs were also taken from experts worked in the floristics of the district and the regional herbaria were also studied.

4.4. Impact on Flora Landslides caused vegetation loss in two ways, uphill areas which suffered landslides and downhill areas which suffered debris/sediment deposition resulting from landslides. All the listed landslide affected areas where phytosociologically surveyed and the species suffered the population loss were reckoned. A total of 376 angiosperms and 21 pteridophytes suffered the population loss (Table 4.7 & 4.8). RESULTS

Table 4.2. Location details of major landslide affected areas surveyed under Wayanad South FD

Altitude Sl. No. Forest Division Latitude Longitude Type of slope movement (m) 1 11.55647222 75.97963889 955 Earth fall 2 11.63972222 75.98008333 951 Earth fall 3 11.55525 75.98133333 929 Earth fall Complex: part rotational, 4 11.6035 75.98761111 1118 part translational 5 11.59758333 75.98761111 950 Earth fall 6 11.59563889 75.98902778 934 Earth fall 7 11.58477778 76.03236111 745 Earth fall Translational planar earth 8 11.55913889 75.97233333 1101 slide 9 11.55938889 75.97205556 1082 Earth fall 10 11.55644444 75.98022222 953 Earth fall

11 11.55652778 75.97963889 966 Rock fall 22 12 11.55538889 75.98133333 933 Earth fall 13 11.54319444 76.01302778 759 Earth fall 14 11.5445 76.01091667 787 Earth topple 15 11.54608333 76.01622222 767 Debris fall 16 11.65980556 75.93661111 778 Earth fall 17 11.63108333 75.98388889 840 Debris fall 18 11.63144444 75.98391667 827 Earth fall 19 11.63127778 75.98177778 876 Successive rotational slide 20 11.62341667 75.97669444 897 Earth fall Translational planar earth 21 11.63461111 75.97094444 774 slide

22 WAYANADSOUTH FOREST DIVISION 11.62233333 75.98652778 894 Earth fall 23 11.62133333 75.98127778 907 Earth fall Translational planar earth 24 11.61991667 75.98069444 942 slide 25 11.62119444 75.97947222 910 Rock fall Complex: part rotational, 26 11.61841667 75.97847222 1076 part translational 27 11.62338889 75.98208333 836 Earth fall 28 11.61869444 75.97675 1083 Earth fall 29 11.53908333 76.00977778 817 Rotational earth slide Translational planar earth 30 11.62169444 75.97294444 988 slide Complex: part rotational, 31 11.61866667 75.97283333 1072 part translational

IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.3. Location details of major landslide affected areas surveyed under Wayanad North FD

Altitude Sl. No. Forest Division Latitude Longitude Type of slope movement (m) Translational planar 1 11.864 75.98138889 860 earth slide 2 11.86325 75.97938889 888 Earth topple Complex: part rotational, 3 11.86219444 75.97833333 907 part translational 4 11.86325 75.97938889 888 Earth topple 5 11.84775 76.00294444 811 Earth fall Translational planar 6 11.85175 76.003 860 earth slide 7 11.84841667 76.00169444 794 Earth fall 8 11.84433333 75.998 773 Earth fall Translational planar 9 11.84072222 75.93347222 698 earth slide Translational planar 10 11.88752778 75.94036111 1029 earth slide 23 11 11.88738889 75.93977778 1033 Earth flow 12 11.88236111 75.96213889 998 Earth fall 13 11.88283333 75.95933333 968 Earth fall 14 11.86169444 75.94113889 809 Earth fall 15 11.86141667 75.94161111 813 Earth fall 16 11.85775 75.94405556 789 Earth fall TH FOREST DIVISION FOREST TH Translational planar 17 11.87233333 76.00755556 1029 NOR earth slide Translational planar 18 11.85305556 76.01 893 earth slide Translational planar 19 11.85197222 76.01002778 885 earth slide WAYANAD Land subsidence / Earth 20 11.85330556 76.03786111 801 spread 21 11.75333333 75.84044444 797 Earth fall Translational planar 22 11.86436111 75.99352778 1041 earth slide 23 11.86163333 75.99961667 1126 Rotational earth slide 24 11.85844444 75.99969444 1010 Earth fall 25 11.85533333 75.99775 918 Earth fall Land subsidence / Earth 26 11.85266667 75.99730556 871 spread Translational planar 27 11.87841667 76.00252778 1071 earth slide 28 11.92619444 75.97905556 1203 Earth fall 29 11.9245 75.97988889 1111 Earth topple

RESULTS

Table 4.4. Location details of minor landslide affected areas surveyed under Wayanad South FD

Altitude Type of slope Sl. No. Forest Division Latitude Longitude (m) movement 1 11.55627778 75.98111111 943 2 11.55491667 75.98169444 926 3 11.55438889 75.98272222 911 4 11.55563889 75.98513889 887 5 11.59758333 75.99036111 950 6 11.55863889 75.97416667 1024 7 11.5585 75.97433333 1022 8 11.55797222 75.97561111 1012 9 11.55713889 75.97780556 981 10 11.55633333 75.98122222 949 11 11.55519444 75.98191667 932

12 11.62452778 75.99277778 769 13 11.62441667 75.99313889 771 24 14 11.54041667 76.0115 798 15 11.54538889 76.01458333 766

16 11.54538889 76.01458333 766 17 11.54538889 76.01458333 766

18 THFOREST DIVISION 11.65375 75.93538889 764 19 Fall Earth

OU 11.65563889 75.93475 767 20 S 11.65561111 75.93455556 768 21 11.65577778 75.93486111 763 22 11.65577778 75.93486111 763

23 WAYANAD 11.65508333 75.93680556 761 24 11.65472222 75.93836111 762 25 11.65472222 75.93836111 762 26 11.65472222 75.93836111 762 27 11.65472222 75.93836111 762 28 11.65758333 75.93719444 772 29 11.65947222 75.93586111 779 30 11.65947222 75.93586111 779 31 11.62236111 75.97472222 965 32 11.62086111 75.98061111 930 33 11.53983333 76.0025 896 34 11.54033333 76.01052778 826

IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.5. Location details of minor landslide affected areas surveyed under Wayanad North FD

Altitude Type of slope Sl. No. Forest Division Latitude Longitude (m) movement 1 11.83652778 75.93205556 720 2 11.85183333 75.91172222 499 3 11.85183333 75.91172222 499 4 11.85144444 75.91272222 525 5 11.86141667 75.94161111 813

6 11.85775 75.94405556 789 7 11.84597222 75.93966667 740 8 11.76294444 75.8345 775 9 11.7475 75.84780556 779

10 11.85141667 76.01138889 826 11 11.85158333 76.01113889 845

12 DIVISION FOREST TH 11.88236111 75.96213889 998 13 11.88236111 75.96213889 998 Fall Earth

NOR 25 14 11.85533333 75.99775 918 15 11.85533333 75.99775 918 16 11.85313889 75.99808333 878

17 WAYANAD 11.90308333 76.01183333 793 18 11.90308333 76.01183333 793 19 11.62269444 75.98736111 896 20 11.9285 75.97905556 1304 21 11.85075 75.80003333 731 22 11.83141667 75.9724 726

1 2 2 1 1 2

4 Earth flow Earth fall Complex: part rotational, part translational Translational planar earth slide 30 Earth topple 13 Debris fall Successive rotational slide Rock fall Land subsidence / Earth spread 4 Rotational earth slide

Figure 4.8. Number of events (major) in each class of Slope movement

RESULTS

Hazard Zonation Map of Wayanad District

Figure 4.9. Landslide Hazard Zonation Map of Wayanad Sl. No. Factors Area (sq. km.) Table 4.6. Total area under each Hazard class 1 Very Low 359.69 We prepared the Landslide Hazard Sl. No. Factors Area (sq. km.) 2 Low 581.63 Zonation map of Wayanad District (Fig. 1 Very Low 359.69 4.9) using Remote Sensing and GIS 3 Moderate 586.98 and by applying several statistical and 4 High2 Low 371.47 581.63 computational models. Spatial analysis 5 Very3 High Moderate 164.75 586.98 using remote sensing and GIS which serves as the best tool for mapping, monitoring

4 High 371.47 and analysis with reasonable accuracy than 5 Very High 164.75 that of extensive time requirement for field investigation and monitoring of landslide vulnerable zones. The methodology is 7.98 weighted overlay, by giving each factor of 17.42 each theme the weight corresponding to their influentially in causing landslide. It 17.99 used ten thematic layers for enumerating 7.98 Very Low Landslide Hazard Zonation map. It has 17.42 Low been found that the 25.97 % area of the Moderate district falls under high and very high-risk 17.99 28.17 zones (Table 4.6, Fig. 4.10). High Very Low Very High 28.43 Figure 4.10.Low Percentage area falling under each HazardModerate class

28.17 High Very High 28.43

IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.11. Major landslide sites overlaid on Landslide Hazard Zonation Map of Wayanad

Figure 4.12. Minor landslide sites overlaid on Landslide Hazard Zonation Map of Wayanad RESULTS

Figure 4.13. Landslide at Pancharakolli [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Talapuzha]. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.14. Major Landslide at Pancharakolli [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Talapuzha]. RESULTS

Figure 4.15. Landslide at Pancharakolli. Opposite to the major landslide inside the semi-evergreen forest. Fissures where seen inside the forest floor metres away from the landslides(Bottom). [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Talapuzha]. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.16. Major Landslide at Maniyankunnu [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Talapuzha]. RESULTS

Figure 4.17. Agriculture land filled with debris from major landslides at Pancharakolli (Top) and Maniyankunnu (Bottom). IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.18. Landslide at Rassalkunnu [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Talapuzha]. RESULTS

Figure 4.19. Landslide at Andikunnu (43 mile) [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Talapuzha]. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.20. Landslide at Sooryamudi [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Talapuzha]. RESULTS

Figure 4.21. Landslide at Muthumari [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Thrissilery]. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.22. Debris runoff of Landslide at Muthumari [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Thrissilery]. RESULTS

Figure 4.23. Landslide at Thacharakolli [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Thrissilery]. Agriculture land filled with landslide debris (bottom). IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.24. Landslide at Priyadarshini [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Talapuzha]. RESULTS

Figure 4.25. Fissures seen inside the Tea estate metres away from the landslides at Priyadarshini IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.26. Landslide at Kurisukuthi [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Talapuzha]. RESULTS

Figure 4.27. Panamkuzhi Forest area [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Talapuzha]. Land subsidence (top), Fissure in forest floor (bottom). IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.28. Landslide at Kambamala [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Tirunelli]. RESULTS

Figure 4.29. Landslide at Brahmagiri [Forest Division: Wayanad North; Forest Range: Begur; Forest Section: Tirunelli]. Three landslides at grassland (top), Fissure in grassland (bottom right) IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.30. Landslide at Peedikapullu [Forest Division: Wayanad South; Forest Range: Kalpetta; Forest Section: Sugandhagiri]. RESULTS

Figure 4.31. Landslide at Peedikapullu [Forest Division: Wayanad South; Forest Range: Kalpetta; Forest Section: Sugandhagiri]. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.32. Landslide at Arikallammottamchal [Forest Division: Wayanad South; Forest Range: Kalpetta; Forest Section: Sugandhagiri]. RESULTS

Figure 4.33. Landslide at Panamkunduchal [Forest Division: Wayanad South; Forest Range: Kalpetta; Forest Section: Sugandhagiri]. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Figure 4.34. Landslide at Kurichiyarmala [Forest Division: Wayanad South; Forest Range: Kalpetta; Forest Beat: Achooranam]. RESULTS

Table 4.7. List of Angiosperm species suffered population loss (Cont...)

Sl. No. Species Family Habit 1 Clematis gouriana Roxb. ex DC. Ranunculaceae Climber 2 Naravelia zeylanica (L.) DC. Ranunculaceae Climber 3 Dillenia bracteata Wight Dilleniaceae Tree 4 Dillenia indica L. Dilleniaceae Tree 5 Artabotrys zeylanicus Hook. f. & Thoms. Annonaceae Climber 6 Meiogyne pannosa (Dalz.) Sinclair Annonaceae Tree 7 Meiogyne ramarowii (Dunn) Gandhi Annonaceae Shrub 8 Miliusa indica Lesch. ex A. DC. Annonaceae Shrub 9 Orophea erythrocarpa Bedd. Annonaceae Tree 10 Orophea malabarica Sasidh. & Sivar. Annonaceae Shrub 11 Orophea uniflora Hook. f. & Thoms. Annonaceae Shrub 12 Phaeanthus malabaricus Bedd. Annonaceae Shrub 13 Polyalthia fragrans (Dalz.) Bedd. Annonaceae Tree

50 14 Anamirta cocculus (L.) Wight & Arn. Menispermaceae Climber 15 Cissampelos pareira L. var. hirsuta (Ham. ex DC.) Menispermaceae Climber Forman 16 Cyclea peltata (Lam.) Hook. f. & Thoms. Menispermaceae Climber 17 Diploclisia glaucescens (Blume)Diels Menispermaceae Climber 18 Tinospora cordifolia (Willd.) Miers. Menispermaceae Climber 19 Cardamine hirsuta L. Brassicaceae Herb 20 Rorippa indica (L.) Hiern. Brassicaceae Herb 21 Capparis cleghornii Dunn ex Gamble Capparaceae Climber 22 Casearia wynadensis Bedd. Flacourtiaceae Tree 23 Flacourtia montana Graham Flacourtiaceae Shrub 24 Hydnocarpus pentandra (Buch.-Ham.) Oken Flacourtiaceae Tree 25 Scolopia crenata (Wight & Arn.) Clos Flacourtiaceae Tree 26 Pittosporum tetraspermum Wight & Arn. Pittosporaceae Shrub 27 Xanthophyllum arnottianum Wight Xanthophyllaceae Tree 28 Drymaria cordata (L.) Willd. ex Roem. & Schult. ssp. Caryophyllaceae Herb diandra (Blume) Duke 29 Polycarpon prostratum (Forssk.) Asch. & Sehweinf. Caryophyllaceae Herb 30 Portulaca oleracea L. Portulacaceae Herb 31 Calophyllum austroindicum Kosterm. ex Stevens Clusiaceae Tree 32 Calophyllum calaba L. Clusiaceae Tree 33 Garcinia cowa Roxb. ex DC. Clusiaceae Tree 34 Garcinia gummi-gutta (L.) Robs. Clusiaceae Tree 35 Garcinia morella (Gaertn.) Desv. Clusiaceae Tree 36 Garcinia rubro-echinata Kosterm. Clusiaceae Tree 37 Mesua ferrea L. Clusiaceae Tree 38 Mesua thwaitesii Planch. & Triana Clusiaceae Tree 39 Poeciloneuron indicum Bedd. Clusiaceae Tree 40 Camellia sinensis (L.) O.Ktze. Theaceae Tree 41 Dipterocarpus indicus Bedd. Dipterocarpaceae Tree 42 Hopea parviflora Bedd. Dipterocarpaceae Tree IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.7. List of Angiosperm species suffered population loss (Cont...)

Sl. No. Species Family Habit 41 Dipterocarpus indicus Bedd. Dipterocarpaceae Tree 42 Hopea parviflora Bedd. Dipterocarpaceae Tree 43 Hopea ponga (Dennst.) Mabb. Dipterocarpaceae Tree 44 Shorea roxburghii G. Don Dipterocarpaceae Tree 45 Vateria indica L. Dipterocarpaceae Tree 46 Ancistrocladus heyneanus Wall. ex Graham Ancistrocladaceae Climber 47 Abelmoschus angulosus Wall. ex Wight & Arn. var. Malvaceae Shrub grandiflorus Thw. 48 Hibiscus hispidissimus Griff. Malvaceae Shrub 49 Kydia calycina Roxb. Malvaceae Tree 50 Malvastrum coromandelianum (L.) Garcke Malvaceae Herb 51 Sida beddomei Jacob Malvaceae Herb 52 Sida rhombifolia L. Malvaceae Shrub 53 Urena lobata L. Malvaceae Shrub 51 54 Bombax ceiba L. Bombacaceae Tree 55 Cullenia exarillata Robyns Bombacaceae Tree 56 Helicteres isora L. Sterculiaceae Shrub 57 Leptonychia caudata (Wall. ex G. Don) Burrett Sterculiaceae Shrub 58 Melochia corchorifolia L. Sterculiaceae Herb 59 Pterospermum rubiginosum Heyne ex Wight & Arn. Sterculiaceae Tree 60 Pterygota alata (Roxb.) R. Br. Sterculiaceae Tree 61 Sterculia guttata Roxb. ex DC. Sterculiaceae Tree 62 Waltheria indica L. Sterculiaceae Shrub 63 Grewia serrulata DC. Tiliaceae Tree 64 Grewia tiliifolia Vahl Tiliaceae Tree 65 Triumfetta pilosa Roth Tiliaceae Shrub 66 Elaeocarpus munronii (Wight) Mast. Elaeocarpaceae Tree 67 Elaeocarpus serratus L. var. weibelii Zmarzty Elaeocarpaceae Tree 68 Elaeocarpus tuberculatus Roxb. Elaeocarpaceae Tree 69 Elaeocarpus variabilis Zmarzty Elaeocarpaceae Tree 70 Biophytum intermedium Wight Oxalidaceae Herb 71 Oxalis corniculata L. Oxalidaceae Herb 72 Acronychia pedunculata (L.) Miq. Rutaceae Tree 73 Atalantia monophylla (L.) DC. Rutaceae Shrub 74 Clausena anisata (Willd.) Hook.f. ex Benth. Rutaceae Shrub 75 Clausena austroindica Stone & K.N. Nair Rutaceae Shrub 76 Clausena indica (Dalz.) Oliver Rutaceae Shrub 77 Glycosmis pentaphylla (Retz.) DC. Rutaceae Shrub 78 Luvunga eleutherandra Dalz. Rutaceae Climber 79 Melicope lunu-ankenda (Gaertn.) Hartley Rutaceae Tree 80 Murraya paniculata (L.) Jack. Rutaceae Shrub 81 Naringi crenulata (Roxb.) Nicolson Rutaceae Tree 82 Toddalia asiatica (L.) Lam. Rutaceae Climber 83 Zanthoxylum rhetsa (Roxb.) DC. Rutaceae Tree RESULTS

Table 4.7. List of Angiosperm species suffered population loss (Cont...)

Sl. No. Species Family Habit 82 Toddalia asiatica (L.) Lam. Rutaceae Climber 83 Zanthoxylum rhetsa (Roxb.) DC. Rutaceae Tree 84 Ailanthus triphysa (Dennst.) Alston Simaroubaceae Tree 85 Quassia indica (Gaertn.) Nooteb. Simaroubaceae Tree 86 Canarium strictum Roxb. Burseraceae Tree 87 Commiphora caudata (Wight & Arn.) Engl. Burseraceae Tree 88 Aglaia lawii (Wight) Saldanha Meliaceae Tree 89 Aglaia barberi Gamble Meliaceae Tree 90 Aphanamixis polystachya (Wall.) Parker Meliaceae Tree 91 Chukrasia tabularis A. Juss. Meliaceae Tree 92 Cipadessa baccifera (Roth) Miq. Meliaceae Shrub 93 Dysoxylum malabaricum Bedd. ex Hiern Meliaceae Tree 94 Melia azedarach L. Meliaceae Tree 95 Meliaceae Shrub 52 Munronia pinnata (Wall.) Harms 96 Reinwardtiodendron anamalaiense (Bedd.) Mabb. Meliaceae Tree 97 Swietenia macrophylla King in Hook. Meliaceae Tree 98 Toona ciliata Roem. Meliaceae Tree 99 Trichilia connaroides (Wight & Arn.) Bentv. Meliaceae Tree 100 Turraea villosa Bennett Meliaceae Shrub 101 Dichapetalum gelonioides (Roxb.) Engl. Dichapetalaceae Shrub 102 Strombosia ceylanica Gard. Olacaceae Tree 103 Naregamia alata Wight & Arn. Meliaceae Herb 104 Apodytes dimidiata Meyer ex Arn. Icacinaceae Tree 105 Gomphandra coriacea Wight Icacinaceae Tree 106 Gomphandra tetrandra (Wall.) Sleumer Icacinaceae Shrub 107 Nothapodytes nimmoniana (Graham) Mabb. Icacinaceae Shrub 108 Erythropalum scandens Blume Erythropalaceae Climber 109 Cassine paniculata (Wight & Arn.) Lobr.-Callen Celastraceae Tree 110 Lophopetalum wightianum Arn. Celastraceae Tree 111 Salacia fruticosa Heyne ex Lawson Hippocrateaceae Climber 112 Ziziphus rugosa Lam. Rhamnaceae Shrub 113 Ampelocissus latifolia (Roxb.) Planch. Vitaceae Climber 114 Cayratia trifolia (L.) Domin Vitaceae Climber 115 Leea asiatica (L.) Ridsd. Leeaceae Shrub 116 Allophylus concanicus Radlk. Sapindaceae Shrub 117 Lepisanthes tetraphylla (Vahl) Radlk. sapindaceae Tree 118 Otonephelium stipulaceum (Bedd.) Radlk. Sapindaceae Tree 119 Schleichera oleosa (Lour.) Oken Sapindaceae Tree 120 Turpinia cochinchinensis (Lour.) Merr. Staphyleaceae Tree 121 Meliosma simplicifolia (Roxb.) Walp. Sabiaceae Tree 122 Mangifera indica L. Anacardiaceae Tree 123 Holigarna arnottiana Hook. f. Anacardiaceae Tree 124 Nothopegia racemosa (Dalz.) Ramam. Anacardiaceae Tree IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.7. List of Angiosperm species suffered population loss (Cont...)

Sl. No. Species Family Habit 123 Holigarna arnottiana Hook. f. Anacardiaceae Tree 124 Nothopegia racemosa (Dalz.) Ramam. Anacardiaceae Tree 125 Semecarpus auriculata Bedd. Anacardiaceae Tree 126 Spondias pinnata (L. f.) Kurz Anacardiaceae Tree 127 Connarus paniculatus Roxb. Connaraceae Climber 128 Abrus precatorius L. Fabaceae Climber 129 Acrocarpus fraxinifolius Wight & Arn. Fabaceae Tree 130 Crotalaria spectabilis Roth Fabaceae Shrub 131 Dalbergia latifolia Roxb. Fabaceae Tree 132 Derris brevipes (Benth.) Baker Fabaceae Climber 133 Erythrina stricta Roxb. Fabaceae Tree 134 Flemingia strobilifera (L.) R. Br. ex Ait.f. Fabaceae Shrub 135 Neonotonia wightii (Graham ex Wight & Arn.) Lackey Fabaceae Climber

136 Pongamia pinnata (L.) Pierre Fabaceae Tree 53 137 Pseudarthria viscida (L.) Wight & Arn. Fabaceae Shrub 138 Pterocarpus marsupium Roxb. Fabaceae Tree 139 Pueraria tuberosa (Roxb. ex Willd.) DC. Fabaceae Tree 140 Pycnospora lutescens (Poir.) Schind. Fabaceae Climber 141 Shuteria involucrata (Wall.) Wight & Arn. Fabaceae Climber 142 Tephrosia purpurea (L.) Pers. Fabaceae Herb 143 Bauhinia phoenicea Wight & Arn. Caesalpiniaceae Climber 144 Caesalpinia mimosoides Lam. Caesalpiniaceae Climber 145 Humboldtia brunonis Wall. Caesalpiniaceae Tree 146 Kingiodendron pinnatum (Roxb. ex DC.) Harms Caesalpiniaceae Tree 147 Tamarindus indica L. Caesalpiniaceae Tree 148 Acacia caesia (L.) Willd. Mimosaceae Climber 149 Acacia melanoxylon R. Br. Mimosaceae Tree 150 Albizia chinensis (Osbeck) Merr. Mimosaceae Tree 151 Albizia odoratissima (L. f.) Benth. Mimosaceae Tree 152 Archidendron bigeminum (L.) Neilson Mimosaceae Tree 153 Archidendron monadelphum (Roxb.) Nielson var. gracile Mimosaceae Tree (Bedd.) Sanjappa 154 Entada rheedei Spreng. Mimosaceae Climber 155 Mimosa pudica L. Mimosaceae Herb 156 Xylia xylocarpa (Roxb.) Taub. Mimosaceae Tree 157 Carallia brachiata (Lour.) Merr. Rhizophoraceae Tree 158 Terminalia bellirica (Gaertn.) Roxb. Combretaceae Tree 159 Terminalia paniculata Roth Combretaceae Tree 160 Eucalyptus grandis Hill ex Maid. Myrtaceae Tree 161 Eugenia argentea Bedd. Myrtaceae Shrub 162 Syzygium caryophyllatum (L.) Alston Myrtaceae Tree 163 Syzygium cumini (L.) Skeels Myrtaceae Tree

RESULTS

Table 4.7. List of Angiosperm species suffered population loss (Cont...)

Sl. No. Species Family Habit 164 Syzygium grande (Wight) Walp. Myrtaceae Tree 165 Syzygium jambos (L.) Alston Myrtaceae Tree 166 Syzygium laetum (Buch.-Ham.) Gandhi Myrtaceae Tree 167 Careya arborea Roxb. Lecythidaceae Tree 168 Melastoma malabathricum L. Melastomataceae Shrub 169 Memecylon randerianum SM & MR Almeida Melastomataceae Shrub 170 Memecylon umbellatum Burm.f. Melastomataceae Shrub 171 Osbeckia aspera (L.) Blume Melastomataceae Shrub 172 Lagerstroemia microcarpa Wight Lythraceae Tree 173 Lagerstroemia parviflora Roxb. Lythraceae Tree 174 Passiflora foetida L. Passifloraceae Climber 175 Diplocyclos palmatus (L.) Jeffrey Cucurbitaceae Climber 176 Luffa cylindrica (L.) Roem. Cucurbitaceae Climber

54 177 Schefflera venulosa (Wight & Arn.) Harms Araliaceae Shrub 178 Chassalia curviflora (Wall. ex Kurz) Thw. var. Rubiaceae Shrub ophioxyloides (Wall.) Deb & Krishna 179 Coffea arabica L. Rubiaceae Shrub 180 Ixora brachiata Roxb. ex DC. Rubiaceae Tree 181 Ixora elongata Heyne ex G. Don Rubiaceae Shrub 182 Mitracarpus hirtus (L.) DC. Rubiaceae Herb 183 Mitragyna tubulosa (Arn.) Hav. Rubiaceae Tree 184 Neanotis rheedei (Wall. ex Wight & Arn.) Lewis Rubiaceae Herb 185 Ochreinauclea missionis (Wall. ex G. Don) Ridsd. Rubiaceae Tree 186 Ophiorrhiza mungos L. Rubiaceae Herb 187 Psychotria flavida Talbot Rubiaceae Shrub 188 Wendlandia thyrsoidea (Schult.) Steud. Rubiaceae Shrub 189 Rubia cordifolia L. Rubiaceae Climber 190 Prunus ceylanica (Wight) Miq. Rosaceae Tree 191 Rubus ellipticus Smith Rosaceae Climber 192 Ageratum conyzoides L. Asteraceae Herb 193 Ageratina adenophora (Spreng.) King & Robins. Asteraceae Shrub 194 Bidens biternata (Lour.) Merr. & Sheriff Asteraceae Herb 195 Chromolaena odorata (L.) King & Robins. Asteraceae Shrub 196 Conyza canadensis (L.) Cronq. Asteraceae Herb 197 Conyza bonariensis (L.) Cronq. Asteraceae Herb 198 Crassocephalum crepidioides (Benth.) S. Moore Asteraceae Herb 199 Dichrocephala integrifolia (L. f.) O. Ktze. Asteraceae Herb 200 Emilia sonchifolia (L.) DC. Asteraceae Herb 201 Lagascea mollis Cav. Asteraceae Herb 202 Launaea acaulis (Roxb.) Babc. ex Kerr. Asteraceae Herb 203 Mikania micrantha Kunth Asteraceae Climber 204 Sigesbeckia orientalis L. Asteraceae Herb 205 Spilanthes radicans Jacq. Asteraceae Herb 206 Vernonia arborea Buch.-Ham. Asteraceae Tree IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.7. List of Angiosperm species suffered population loss (Cont...)

Sl. No. Species Family Habit 205 Spilanthes radicans Jacq. Asteraceae Herb 206 Vernonia arborea Buch.-Ham. Asteraceae Tree 207 Lobelia nicotianifolia Roth ex Roem. & Schult. Lobeliaceae Shrub 208 Embelia ribes Burm. f. Myrsinaceae Climber 209 Maesa indica (Roxb.) DC. Myrsinaceae Shrub 210 Palaquium ellipticum (Dalz.) Baill. Sapotaceae Tree 211 Diospyros ovalifolia Wight Ebenaceae Tree 212 Diospyros pruriens Dalz. Ebenaceae Tree 213 Symplocos cochinchinensis (Lour.) Moore ssp. laurina Symplocaceae Tree (Retz.) Nooteb. 214 Symplocos racemosa Roxb. Symplocaceae Tree 215 Symplocos wynadense (O. Ktze.) Nooteb. Symplocaceae Shrub 216 Olea dioica Roxb. Oleaceae Tree 217 Chionanthus courtallensis Bedd. Oleaceae Tree 55 218 Chionanthus mala-elengi (Dennst.) P. S. Green Oleaceae Tree 219 Jasminum flexile Vahl Oleaceae Climber 220 Ligustrum robustum (Roxb.) Blume Oleaceae Tree 221 Myxopyrum smilacifolium (Wall.) Blume Oleaceae Climber 222 Alstonia scholaris (L.) R. Br. Apocynaceae Tree 223 Rauvolfia verticillata (Lour.) Baill. Apocynaceae Shrub 224 Tabernaemontana alternifolia L. Apocynaceae Tree 225 Tabernaemontana gamblei Subram. & Henry Apocynaceae Shrub 226 Wrightia tinctoria (Roxb.) R. Br. Apocynaceae Tree 227 Asclepias curassavica L. Asclepiadaceae Herb 228 Gymnema sylvestre (Retz.) R. Br. ex Schult. Asclepiadaceae Climber 229 Hemidesmus indicus (L.) R. Br. Asclepiadaceae Climber 230 Gardneria ovata Wall. Loganiaceae Climber 231 Strychnos colubrina L. Loganiaceae Climber 232 Canscora diffusa (Vahl) R. Br. ex Roem. & Schult. Gentianaceae Herb 233 Exacum carinatum Roxb. Gentianaceae Herb 234 Exacum sessile L. Gentianaceae Herb 235 Exacum tetragonum Roxb. Gentianaceae Herb 236 Swertia lawii (Wight ex Clarke) Burkill Gentianaceae Herb 237 Heliotropium indicum L. Boraginaceae Herb 238 Ipomoea hederifolia L. Convolvulaceae Climber 239 Merremia vitifolia (Burm. f.) Hall. f. Convolvulaceae Climber 240 Physalis angulata L. Solanaceae Herb 241 Solanum virginianum L. Solanaceae Shrub 242 Solanum torvum Sw. Solanaceae Shrub 243 Utricularia graminifolia Vahl Lentibulariaceae Herb 244 Aeschynanthus perrottetii A.DC. Gesneriaceae Shrub 245 Stereospermum colais (Buch.-Ham. ex Dillw.) Mabb. Bignoniaceae Tree 246 Hypoestes sanguinolenta Hook. Acanthaceae Herb 247 Strobilanthes barbatus Nees Acanthaceae Shrub RESULTS

Table 4.7. List of Angiosperm species suffered population loss (Cont...)

Sl. No. Species Family Habit 246 Hypoestes sanguinolenta Hook. Acanthaceae Herb 247 Strobilanthes barbatus Nees Acanthaceae Shrub 248 Strobilanthes ciliatus Nees Acanthaceae Shrub 249 Strobilanthes lupulinus Nees Acanthaceae Shrub 250 Strobilanthes rubicundus (Nees) Anders Acanthaceae Shrub 251 Thunbergia mysorensis (Wight) Anders. Acanthaceae Climber 252 Thunbergia fragrans Roxb. Acanthaceae Climber 253 Callicarpa tomentosa (L.) Murray Verbenaceae Shrub 254 Clerodendrum philippinum Schauer Verbenaceae Shrub 255 Clerodendrum infortunatum L. Verbenaceae Shrub 256 Gmelina arborea Roxb. Verbenaceae Tree 257 Lantana camara L. Verbenaceae Shrub 258 Stachytarpheta cayennensis (Rich.) Schauer Verbenaceae Shrub

56 259 Stachytarpheta jamaicensis (L.) Vahl Verbenaceae Shrub 260 Tectona grandis L. Verbenaceae Tree 261 Vitex pinnata L. Verbenaceae Tree 262 Colebrookea oppositifolia Smith Lamiaceae Shrub 263 Hyptis suaveolens (L.) Poit. Lamiaceae Shrub 264 Pogostemon purpurascens Dalz. Lamiaceae Herb 265 Boerhavia diffusa L. Nyctaginaceae Herb 266 Achyranthes aspera L. Amaranthaceae Herb 267 Aristolochia brasiliensis Mart. & Zucc. Aristolochiaceae Climber 268 Thottea siliquosa (Lam.) Ding Hou Aristolochiaceae Shrub 269 Lepianthes umbellata (L.) Rafin. Piperaceae Shrub 270 Peperomia pellucida (L.) Kunth Piperaceae Herb 271 Piper longum L. Piperaceae Shrub 272 Piper nigrum L. Piperaceae Climber 273 Sarcandra chloranthoides Gard. Chloranthaceae Shrub 274 Knema attenuata (Hook. f. & Thoms.) Warb. Myristicaceae Shrub 275 Myristica beddomei King Myristicaceae Tree 276 Myristica malabarica Lam. Myristicaceae Tree 277 Actinodaphne bourdillonii Gamble Lauraceae Tree 278 Actinodaphne malabarica Balakr. Lauraceae Tree 279 Apollonias arnottii Nees Lauraceae Tree 280 Cinnamomum malabatrum (Burm. f.) Blume Lauraceae Tree 281 Cinnamomum sulphuratum Nees Lauraceae Tree 282 Litsea beddomei Hook. f. Lauraceae Tree 283 Litsea bourdillonii Gamble Lauraceae Tree 284 Litsea coriacea (Heyne ex Meisner) Hook. f. Lauraceae Tree 285 Litsea mysorensis Gamble Lauraceae Tree 286 Litsea floribunda (Blume) Gamble Lauraceae Tree 287 Neolitsea cassia (L.) Kosterm. Lauraceae Tree 288 Neolitsea scrobiculata (Meisner) Gamble lauraceae Tree IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.7. List of Angiosperm species suffered population loss (Cont...)

Sl. No. Species Family Habit 287 Neolitsea cassia (L.) Kosterm. Lauraceae Tree 288 Neolitsea scrobiculata (Meisner) Gamble lauraceae Tree 289 Persea macrantha (Nees) Kosterm. Lauraceae Tree 290 Phoebe lanceolata Nees Lauraceae Tree 291 Grevillea robusta Cunn. Proteaceae Tree 292 Gnidia glauca (Fresen.) Gilg Thymeleaceae Shrub 293 Elaeagnus kologa Schult. Elaeagnaceae Climber 294 Dendrophthoe falcata (L. f.) Etting. Loranthaceae Shrub 295 Taxillus tomentosus (Heyne ex Roth) Tieghem Loranthaceae Shrub 296 Balanophora fungosa J. R. & G. Forst. ssp. indica (Arn.) Balanophoraceae Herb Hansen 297 Acalypha indica L. Euphorbiaceae Herb 298 Antidesma acidum Retz. Euphorbiaceae Shrub 299 Antidesma montanum Blume Euphorbiaceae Tree 57 300 Aporosa cardiosperma (Gaertn.) Merr. Euphorbiaceae Tree 301 Bischofia javanica Blume Euphorbiaceae Tree 302 Briedelia stipularis (L.) Blume Euphorbiaceae Shrub 303 Croton bonplandianus Baill. Euphorbiaceae Herb 304 Drypetes venusta (Wight) Pax & Hoffm. Euphorbiaceae Tree 305 Euphorbia hirta L. Euphorbiaceae Herb 306 Euphorbia rothiana Spreng. Euphorbiaceae Shrub 307 Euphorbia heterophylla L. Euphorbiaceae Herb 308 Homonoia riparia Lour. Euphorbiaceae Shrub 309 Macaranga peltata (Roxb.) Muell.-Arg. Euphorbiaceae Tree 310 Mallotus tetracoccus (Roxb.) Kurz Euphorbiaceae Tree 311 Mallotus philippensis (Lam.) Muell.-Arg. Euphorbiaceae Tree 312 Phyllanthus emblica L. Euphorbiaceae Tree 313 Debregeasia longifolia (Burm. f.) Wedd. Urticaceae Shrub 314 Laportea interrupta (L.) Chew Urticaceae Herb 315 Oreocnide integrifolia (Gaud.) Miq. Urticaceae Shrub 316 Pellionia heyneana Wedd. Urticaceae Herb 317 Procris crenata Robins. Urticaceae Herb 318 Celtis tetrandra Roxb. Urticaceae Tree 319 Trema orientalis (L.) Blume Ulmaceae Tree 320 Artocarpus heterophyllus Lam. Moraceae Tree 321 Artocarpus hirsutus Lam. Moraceae Tree 322 Ficus exasperata Vahl Moraceae Tree 323 Ficus racemosa L. Moraceae Tree 324 Ficus rigida Jack var. bracteata (Corner) Bennet Moraceae Tree 325 Ficus tsjahela Burm. f. Moraceae Tree 326 Salix tetrasperma Roxb. Salicaceae Tree 327 Calanthe sylvatica (Thouars) Lindl. Orchidaceae Herb 328 Conchidium braccatum (Lindl.) Brieger Orchidaceae Herb 329 Cymbidium aloifolium (L.) Sw. Orchidaceae Herb RESULTS

Table 4.7. List of Angiosperm species suffered population loss (Cont...)

Sl. No. Species Family Habit 328 Conchidium braccatum (Lindl.) Brieger Orchidaceae Herb 329 Cymbidium aloifolium (L.) Sw. Orchidaceae Herb 330 Disperis neilgherrensis Wight Orchidaceae Herb 331 Oberonia brachyphylla Blatt. & McCann Orchidaceae Herb 332 Pholidota imbricata Hook. Orchidaceae Herb 333 Curcuma neilgherrensis Wight Zingiberaceae Herb 334 Elettaria cardamomum (L.) Maton Zingiberaceae Herb 335 Hellenia speciosa (J. Koenig) Govaerts Costaceae Herb 336 Schumannianthus virgatus (Roxb.) Rolfe Marantaceae Shrub 337 Stachyphrynium spicatum (Roxb.) Schum. Marantaceae Herb 338 Ensete superbum (Roxb.) Cheesman Musaceae Shrub 339 Dioscorea oppositifolia L. Dioscoreaceae Climber 340 Smilax wightii A. DC. Smilacaceae Climber 58 341 Smilax zeylanica L. Smilacaceae Climber 342 Curculigo orchioides Gaertn. Hypoxidaceae Herb 343 Molineria trichocarpa (Wight) Balakr. Hypoxidaceae Herb 344 Asparagus racemosus Willd. Liliaceae Climber 345 Dictyospermum montanum Wight Commelinaceae Herb 346 Floscopa scandens Lour. Commelinaceae Herb 347 Juncus prismatocarpus R. Br. ssp. leschenaultii (Gay ex Juncaceae Herb Laharpe) Kirschner 348 Areca catechu L. Arecaceae Tree 349 Calamus sp. Arecaceae Climber 350 Caryota urens L. Arecaceae Tree 351 Cocos nucifera L. Arecaceae Tree 352 Phoenix loureiroi Kunth Arecaceae Shrub 353 Pandanus canaranus Warb. Pandanaceae Shrub 354 Pothos scandens L. Araceae Climber 355 Rhaphidophora pertusa (Roxb.) Schott Araceae Climber 356 Eriocaulon conicum (Fyson) C.E.C. Fisch. Eriocaulaceae Herb 357 Bulbostylis barbata (Rottb.) Kunth ex Clarke Cyperaceae Herb 358 Cyperus rotundus L. Cyperaceae Herb 359 Lipocarpha chinensis (Osbeck) Kern Cyperaceae Herb 360 Fimbristylis dichotoma (L.) Vahl Cyperaceae Herb 361 Hypolytrum nemorum (Vahl) Spreng. Cyperaceae Herb 362 Kyllinga brevifolia Rottb. Cyperaceae Herb 363 Pycreus flavidus (Retz.) Koyama Cyperaceae Herb 364 Scleria lithosperma (L.) Sw. Cyperaceae Herb 365 Arundinella ciliata (Roxb.) Nees ex Miq. Poaceae Herb 366 Bambusa sp. Poaceae Shrub 367 Centotheca lappacea (L.) Desv. Poaceae Herb 368 Cymbopogon flexuosus (Nees ex Steud.) Wats. Poaceae Herb 369 Echinochloa colona (L.) Link Poaceae Herb 370 Eragrostis unioloides (Retz.) Nees ex Steud. Poaceae Herb IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.7. List of Angiosperm species suffered population loss

Sl. No. Species Family Habit 369 Echinochloa colona (L.) Link Poaceae Herb 370 Eragrostis unioloides (Retz.) Nees ex Steud. Poaceae Herb 371 Heteropogon contortus (L.) P. Beauv. ex Roem. & Poaceae Herb Schult. 372 Imperata cylindrica (L.) Raeusch. Poaceae Herb 373 Ochlandra travancorica (Bedd.) Benth. ex Gamble Poaceae Shrub 374 Paspalum conjugatum Berg. Poaceae Herb 375 Pennisetum polystachyon (L.) Schult. Poaceae Herb 376 Themeda cymbaria (Roxb.) Hack. Poaceae Herb

53 59 83

Climber Tree Shrub Herb

86 154

Figure 4.35. Number of species in each habit class

Of the 376 angiosperm species suffered the population loss, a majority of them are trees with 154 taxa followed by shrubs and herbs with 86 and 83 taxa respectively (Fig. 4.35). Conservation status of 58 species are known (Table 4.9) and 14 of them falls under different threat category (IUCN, 2019) (Fig. 4.37). Eighty- one species were found to be native and of restricted distribution (Table 4.10), of which 40 species are endemic to the southern Western Ghats and another 23 to the Western Ghats (Fig. 4.38). Five pteridophytes were also found to be endemic and 7 are under different threat categories (Fig. 4.36). Of the angiosperm species suffered the population loss 46 where sourced of NWFP (Table 4.11, Fig. 4.39) and 200 has known medicinal properties (Table 4.12). During the survey it is also noted that 45 species of known invasive nature are establishing in landslide affected areas (Table 4.13). RESULTS

Table 4.8. List of Pteridophytes suffered population loss

Sl. No. Species Family Status

1 Adiantum concinnum Humb. & Bonpl.ex Willd. Adiantaceae

2 Adiantum latifolium Lam. Adiantaceae

3 Angiopteris helferiana C. Presl Marattiaceae 4 Anisocampium cumingianum C. Presl Athyriaceae Rare

5 Asplenium cheilosorum Kunze ex Mett. Aspleniaceae 6 Botrychium daucifolium Wall. ex Hook. & Grev. Ophioglossaceae Rare 7 Diplazium cognatum (Hieron.) Sledge Athyriaceae Threatened

8 Diplazium esculentum (Retz.) Sw Athyriaceae 9 Dryopteris austro-indica Fraser-Jenk. Dryopteridaceae Endemic, Threatened

10 Equisetum ramosissimum Desf. Equisetaceae

11 Lygodium flexuosum (L.) Sw. Lygodiaceae

12 Lygodium microphyllum (Cav.) R. Br. Lygodiaceae 13 Oreogrammitis attenuata (Ravi & J. Joseph) Parris Grammitidaceae Endemic; Threatened 60 14 Osmunda huegeliana C. Presl Osmundaceae Endemic; Rare

15 Psilotum nudum (L.) P. Beauv. Psilotaceae

16 Pteris biaurita L. Pteridaceae

17 Pteris confusa T. G. Walker Pteridaceae 18 Pteris heteromorpha Fee Pteridaceae Rare

19 Selaginella proniflora (Lam.) Bak. Selaginellaceae 20 Selaginella radicata (Hook. & Grev.) Spring Selaginellaceae Endemic 21 Selaginella tenera (Hook. & Grev.) Spring Selaginellaceae Endemic

2 3 3

Ferns Lycophytes Endemic Threatened Endemic & Threatened

Figure 4.36. Number of Pteridophytes in each conservation status and two morphological groups IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.9. Conservation status of Angiosperm species suffered population loss (Cont...)

Sl. No. Species Conservation Status 1 Acacia caesia (L.) Willd. Least Concern 2 Aglaia lawii (Wight) Saldanha Lower Risk/Least Concern 3 Alstonia scholaris (L.) R. Br. Lower Risk/Least Concern 4 Antidesma montanum Blume Least Concern 5 Aphanamixis polystachya (Wall.) Parker Least Concern 6 Artocarpus hirsutus Lam. Least Concern 7 Bischofia javanica Blume Least Concern 8 Camellia sinensis (L.) O.Ktze. Data Deficient 9 Caryota urens L. Least Concern 10 Casearia wynadensis Bedd. Vulnerable 11 Celtis tetrandra Roxb. Least Concern 12 Chukrasia tabularis A. Juss. Least Concern 13 Cinnamomum sulphuratum Nees Vulnerable

14 Coffea arabica L. Endangered 61 15 Cyperus rotundus L. Least Concern 16 Dalbergia latifolia Roxb. Vulnerable 17 Dysoxylum malabaricum Bedd. ex Hiern Endangered 18 Echinochloa colona (L.) Link Least Concern 19 Elaeocarpus munronii (Wight) Mast. Lower Risk/Near Threatened 20 Eragrostis unioloides (Retz.) Nees ex Steud. Least Concern 21 Eriocaulon conicum (Fyson) C.E.C. Fisch. Least Concern 22 Ficus exasperata Vahl Least Concern 23 Fimbristylis dichotoma (L.) Vahl Least Concern 24 Floscopa scandens Lour. Least Concern 25 Garcinia rubro-echinata Kosterm. Vulnerable 26 Homonoia riparia Lour. Least Concern 27 Hopea parviflora Bedd. Least Concern 28 Hopea ponga (Dennst.) Mabb. Endangered 29 Hydnocarpus pentandrus (Buch.-Ham.) Oken Vulnerable 30 Juncus prismatocarpus R. Br. ssp. leschenaultii (Gay ex Least Concern Laharpe) Kirschner 31 Kingiodendron pinnatum (Roxb. ex DC.) Harms Endangered 32 Knema attenuata (Hook. f. & Thoms.) Warb. Lower Risk/Least Concern 33 Kyllinga brevifolia Rottb. Least Concern 34 Lipocarpha chinensis (Osbeck) Kern Least Concern 35 Lophopetalum wightianum Arn. Lower Risk/Least Concern 36 Mangifera indica L. Data Deficient 37 Melia azedarach L. Least Concern 38 Melicope lunu-ankenda (Gaertn.) Hartley Least Concern 39 Mimosa pudica L. Least Concern 40 Myristica malabarica Lam. Vulnerable 41 Neonotonia wightii (Graham ex Wight & Arn.) Lackey Least Concern 42 Ochreinauclea missionis (Wall. ex G. Don) Ridsd. Vulnerable 43 Orophea uniflora Hook. f. & Thoms. Vulnerable 44 Paspalum conjugatum Berg. Least Concern RESULTS

Table 4.9. Conservation status of Angiosperm species suffered population loss

Sl. No. Species Conservation Status 41 Neonotonia wightii (Graham ex Wight & Arn.) Lackey Least Concern 42 Ochreinauclea missionis (Wall. ex G. Don) Ridsd. Vulnerable 43 Orophea uniflora Hook. f. & Thoms. Vulnerable 44 Paspalum conjugatum Berg. Least Concern 45 Phaeanthus malabaricus Bedd. Lower Risk/Near Threatened 46 Pongamia pinnata (L.) Pierre Least Concern 47 Pterocarpus marsupium Roxb. Near Threatened 48 Pycreus flavidus (Retz.) Koyama Least Concern 49 Scleria lithosperma (L.) Sw. Least Concern 50 Shorea roxburghii G. Don Vulnerable 51 Stachyphrynium spicatum (Roxb.) Schum. Least Concern 52 Syzygium jambos (L.) Alston Least Concern 53 Tabernaemontana gamblei Subram. & Henry Lower Risk/Conservation Dependent 62 54 Toona ciliata Roem. Least Concern 55 Trema orientalis (L.) Blume Least Concern 56 Utricularia graminifolia Vahl Least Concern 57 Vateria indica L. Critically Endangered 58 Vitex pinnata L. Least Concern

Critically Endangered Endangered Vulnerable 14 2 1 4 ConservationCritically dependent Endangered Near ThreatenedEndangered 9 Vulnerable 14 Least concern 2 1 4 Conservation dependent 1 Data DeficientNear Threatened 9 3 ThreatenedLeast concern 38 1 Lower RiskData Deficient 3 42 Threatened 38 Lower Risk 42

Figure 4.37. Conservation status of Species IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.10. List of Endemic species suffered population loss (Cont...)

Sl. No. Species Family Endemic to 1 Actinodaphne bourdillonii Gamble Lauraceae Southern Western Ghats 2 Actinodaphne malabarica Balakr. Lauraceae Southern Western Ghats 3 Aeschynanthus perrottetii A.DC. Gesneriaceae Western Ghats 4 Aglaia barberi Gamble Meliaceae Southern Western Ghats 5 Allophylus concanicus Radlk. Sapindaceae Western Ghats 6 Ancistrocladus heyneanus Wall. ex Graham Ancistrocladaceae Western Ghats 7 Apollonias arnottii Nees Lauraceae Southern Western Ghats 8 Archidendron monadelphum (Roxb.) Nielson Mimosaceae Southern Western Ghats var. gracile (Bedd.) Sanjappa 9 Artocarpus hirsutus Lam. Moraceae Southern Western Ghats 10 Arundinella ciliata (Roxb.) Nees ex Miq. Poaceae Peninsular India 11 Bauhinia phoenicea Wight & Arn. Caesalpiniaceae Western Ghats 12 Bridelia stipularis (L.) Bl. Euphorbiaceae Peninsular India 13 Calophyllum calaba L. Clusiaceae Southern Western Ghats 14 Capparis cleghornii Dunn ex Gamble Capparaceae South India 63 15 Casearia wynadensis Bedd. Flacourtiaceae Southern Western Ghats (Kerala) 16 Chionanthus courtallensis Bedd. Oleaceae Southern Western Ghats 17 Chionanthus mala-elengi (Dennst.) P. S. Green Oleaceae Peninsular India 18 Cinnamomum malabatrum (Burm. f.) Blume Lauraceae Southern Western Ghats 19 Cinnamomum sulphuratum Nees Lauraceae Western Ghats 20 Clausena austroindica Stone & K.N. Nair Rutaceae Southern Western Ghats 21 Cullenia exarillata Robyns Bombacaceae Southern Western Ghats 22 Derris brevipes (Benth.) Baker Fabaceae Western Ghats 23 Dillenia bracteata Wight Dilleniaceae Western Ghats 24 Diospyros pruriens Dalz. Ebenaceae Western Ghats 25 Dipterocarpus indicus Bedd. Dipterocarpaceae Western Ghats 26 Drypetes venusta (Wight) Pax & Hoffm. Euphorbiaceae Southern Western Ghats 27 Dysoxylum malabaricum Bedd. ex Hiern Meliaceae Southern Western Ghats 28 Elaeocarpus munronii (Wight) Mast. Elaeocarpaceae Southern Western Ghats 29 Ensete superbum (Roxb.) Cheesman Musaceae Peninsular India 30 Eriocaulon conicum (Fyson) C.E.C. Fisch. Eriocaulaceae Peninsular India 31 Eugenia argentea Bedd. Myrtaceae Southern Western Ghats (Kerala) 32 Flacourtia montana Graham Flacourtiaceae Western Ghats 33 Garcinia rubro-echinata Kosterm. Clusiaceae Western Ghats 34 Holigarna arnottiana Hook. f. Anacardiaceae Southern Western Ghats 35 Humboldtia brunonis Wall. Caesalpiniaceae Southern Western Ghats 36 Hydnocarpus pentandra (Buch.-Ham.) Oken Flacourtiaceae Western Ghats 37 Ixora elongata Heyne ex G. Don Rubiaceae Endemic to India 38 Kingiodendron pinnatum (Roxb. ex DC.) Caesalpiniaceae Southern Western Ghats Harms 39 Knema attenuata (Hook. f. & Thoms.) Warb. Myristicaceae Western Ghats 40 Lagerstroemia microcarpa Wight Lythraceae Western Ghats Sl. No. Species Family Endemic to 41 Litsea beddomei Hook. f. Lauraceae Southern Western Ghats 42 Litsea bourdillonii Gamble Lauraceae Southern Western Ghats RESULTS

Table 4.10. List of Endemic species suffered the population loss Sl. No. Species Family Endemic to 41 Litsea beddomei Hook. f. Lauraceae Southern Western Ghats 42 Litsea bourdillonii Gamble Lauraceae Southern Western Ghats 43 Litsea coriacea (Heyne ex Meisner) Hook. f. Lauraceae Peninsular India 44 Litsea mysorensis Gamble Lauraceae South India 45 Luvunga eleutherandra Dalz. Rutaceae Western Ghats 46 Meiogyne pannosa (Dalz.) Sinclair Annonaceae Western Ghats 47 Meiogyne ramarowii (Dunn) Gandhi Annonaceae Southern Western Ghats 48 Memecylon randerianum SM & MR Almeida Melastomataceae Southern Western Ghats 49 Mitragyna tubulosa (Arn.) Hav. Rubiaceae Peninsular India 50 Myristica malabarica Lam. Myristicaceae Western Ghats 51 Nothopegia racemosa (Dalz.) Ramam. Anacardiaceae Western Ghats 52 Oberonia brachyphylla Blatt. & McCann Orchidaceae Southern Western Ghats 53 Ochlandra travancorica (Bedd.) Benth. ex Poaceae Southern Western Ghats Gamble 54 Rubiaceae Southern Western Ghats 64 Ochreinauclea missionis (Wall. ex G. Don) Ridsd. 55 Orophea malabarica Sasidh. & Sivar. Annonaceae Southern Western Ghats 56 Orophea uniflora Hook. f. & Thoms. Annonaceae Southern Western Ghats 57 Palaquium ellipticum (Dalz.) Baill. Sapotaceae Western Ghats 58 Pandanus canaranus Warb. Pandanaceae Peninsular India 59 Phaeanthus malabaricus Bedd. Annonaceae Southern Western Ghats 60 Poeciloneuron indicum Bedd. Clusiaceae Western Ghats 61 Pogostemon purpurascens Dalz. Lamiaceae South-West India 62 Polyalthia fragrans (Dalz.) Bedd. Annonaceae Southern Western Ghats 63 Psychotria flavida Talbot Rubiaceae Peninsular India 64 Pterospermum rubiginosum Heyne ex Wight & Sterculiaceae Southern Western Ghats Arn. 65 Reinwardtiodendron anamalaiense (Bedd.) Meliaceae Southern Western Ghats Mabb. 66 Salacia fruticosa Heyne ex Lawson Hippocrateaceae Western Ghats 67 Semecarpus auriculata Bedd. Anacardiaceae Southern Western Ghats 68 Smilax wightii A. DC. Smilacaceae Southern Western Ghats 69 Strobilanthes barbatus Nees Acanthaceae Western Ghats 70 Strobilanthes ciliatus Nees Acanthaceae Southern Western Ghats 71 Strobilanthes lupulinus Nees Acanthaceae Peninsular India 72 Strobilanthes rubicundus (Nees) Anders Acanthaceae Southern Western Ghats 73 Swertia lawii (Wight ex Clarke) Burkill Gentianaceae Southern Western Ghats 74 Symplocos wynadense (O. Ktze.) Nooteb. Symplocaceae Southern Western Ghats 75 Syzygium laetum (Buch.-Ham.) Gandhi Myrtaceae Southern Western Ghats 76 Tabernaemontana gamblei Subram. & Henry Apocynaceae Southern Western Ghats 77 Terminalia paniculata Roth Combretaceae Peninsular India 78 Themeda cymbaria (Roxb.) Hack. Poaceae Peninsular India 79 Thunbergia mysorensis (Wight) Anders. Acanthaceae Western Ghats 80 Vateria indica L. Dipterocarpaceae Southern Western Ghats 81 Xanthophyllum arnottianum Wight Xanthophyllaceae Southern Western Ghats

IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Vateria indica L.

a c Vateria indica L. (a) Flowering twig; (b) Dried tree in a landslide affected area; (c) A landslide affected area with fallen trees.

It classifies the plant as ‘Critically Endangered’ in the IUCN Red List of Threatened Species. The species is slow-growing, with few healthy populations remaining. It has been over-exploited for its timber, for the plywood industry, whilst loss of habitat and other human activities have also contributed to population declines. The tree belonging to the family Dipterocarpaceae distributed in southern Western Ghats in evergreen and semi-evergreen forests, mostly along streams. V. indica is an evergreen tree up to 40 m in height with 10–12 mm thick and smooth bark, which is greyish, blotched with white and green. A sticky, resinous exudation, also called white dammar, is extracted by scratching the tree’s bark. It is used as incense and as an Ayurvedic medicine. As per the quantitative vegetation analysis it has been noted that this species suffered the major population loss in the landslides occurred in the forest areas. An estimate based on the tree debris in the runoff of landslides had shown that the trees fallen comes within the girth class 120–180. The average crown spread of a tree was found to be 27.2 ± 3.88 m and height up to first branching 27.2 ± 3.05 m. The mature trees were found to be having a mean GBH of 1.37 ± 0.17 m and average bio volume was found to be 54.17 ± 15.65 m3. By direct volume measurement of the trunks, it is estimated that about 5,958.651 m3 of wood of this species has been lost as part of the landslides. RESULTS

Fig. 4.38. Number of Endemic species suffered population loss

Table 4.11. List of NWFPs suffered population loss (Cont...)

Sl. No. Species Family Part used 1 Acacia caesia (L.) Willd. Mimosaceae Bark 2 Ailanthus triphysa (Dennst.) Alston Simaroubaceae Resin 3 Alstonia scholaris (L.) R. Br. Apocynaceae Bark 4 Anamirta cocculus (L.) Wight &Arn. Menispermaceae Seed 5 Aphanamixis polystachya (Wall.) Parker Meliaceae Bark 6 Areca catechu L. Arecaceae Fruit 7 Asparagus racemosus Willd. Liliaceae Root 8 Biophytum intermedium Wight Oxalidaceae Entire plant 9 Boerhavia diffusa L. Nyctaginaceae Root 10 Cinnamomum malabatrum (Burm. f.) Blume Lauraceae Bark 11 Cinnamomum sulphuratum Nees Lauraceae Bark 12 Cyclea peltata (Lam.) Hook. f. & Thoms. Menispermaceae Root 13 Dysoxylum malabaricum Bedd. ex Hiern Meliaceae Bark 14 Elettaria cardamomum (L.) Maton Zingiberaceae Fruit 15 Embelia ribes Burm. f. Myrsinaceae Fruit 16 Entada rheedei Spreng. Mimosaceae Seed 17 Ficu sracemosa L. Moraceae Bark 18 Garcinia gummi-gutta (L.) Robs. Clusiaceae Fruit 19 Gmelina arborea Roxb. Verbenaceae Root 20 Helicteres isora L. Sterculiaceae Fruit 21 Hellenia speciosa (J. Koenig) Govaerts Costaceae Root 22 Hemidesmus indicus (L.) R. Br. Asclepiadaceae Root 23 Hydnocarpus pentandra (Buch.-Ham.) Oken Flacourtiaceae Fruit 24 Kingiodendron pinnatum (Roxb. ex DC.) Harms Caesalpinaceae Wood oil

Table 4.11. List of NWFPs suffered population loss

Sl. No. Species Family Part used 25 Mesua ferrea L. Clusiaceae Flowers & Seeds 26 Naregamia alata Wight & Arn. Meliaceae Root 27 Palaquium ellipticum (Dalz.) Baill. Sapotaceae Seed 28 Persea macrantha (Nees) Kosterm. Lauraceae Bark 29 Phoenix loureiroi Kunth Arecaceae Leaves 30 Phyllanthus emblica L. Euphorbiaceae Fruit 31 Piper longum L. Piperaceae Fruit, Stem & Root 32 Piper nigrum L. Piperaceae Fruit & Stem 33 Pongamia pinnata (L.) Pierre Fabaceae Bark 34 Pseudarthria viscida (L.) Wight & Arn. Fabaceae Root 35 Rubia cordifolia L. Rubiaceae Root 36 Schleichera oleosa (Lour.) Oken Sapindaceae Seed 37 Sida rhombifolia L. Malvaceae Root 38 Solanum torvum Sw. Solanaceae Root 39 Spondias pinnata (L. f.) Kurz Anacardiaceae Bark 67 40 Stereospermum colais (Buch.-Ham. ex Dillw.) Bignoniaceae Root Mabb. 41 Strobilanthes ciliatus Nees Acanthaceae Root 42 Symplocos cochinchinensis (Lour.) Moore ssp. Symplocaceae Bark laurina (Retz.) Nooteb. 43 Terminalia bellirica (Gaertn.) Roxb. Combretaceae Fruit 44 Tinospora cordifolia (Willd.) Miers. Menispermaceae Stem 45 Vateria indica L. Dipterocarpaceae Resin 46 Wrightia tinctoria (Roxb.) R. Br. Apocynaceae Leaves

1 1 1 1 21 1 1 2 1 4 11 4 11 EntireEntire plant plant Fruit,Fruit, Stem Stem & & Root Root FlowersFlowers & &Seeds Seeds FruitFruit & Stem& Stem Bark Bark 2 2 ResinResin Fruit FruitRoot 13 RootSeed 13 SeedLeaves 8 1 81 LeavesWood oil 1 1 WoodStem oil Stem

Fig. 4.39. Number of NWFP species under different use class RESULTS

Pachotti – പാേച്ചാറ്റി —Symplocos cochinchinensis (Lour.) S. Moore ssp. laurina (Retz.) Noot.

Symplocos cochinchinensis (Lour) S. Moore ssp. Laurina Symplocos racemosa Roxb. (Retz.) Noot. 68

Tree with skinned bark Bark strewn out in rocks and forest floor for sun drying

Symplocos cochinchinensis ssp. laurina (Symplocaceae) is a medicinal plant with anti-inflammatory, antitumor, antimicrobial and antidiabetic properties (Sunil et al., 2011, 2012). The bark of this plant is one of the key ingredients of Nisakathakadi Kashayam (decoction); a very effective Ayurvedic preparation for diabetes mentioned in the ancient script ‘Sahasrayogam’ (Krishnanvaidyan & Pillai, 2000). This is an evergreen tree, grows up to 15 m high, with smooth creamy white bark which is thin and light grey. This plant is also substituted with Symplocos racemosa Roxb. As per available ethnobotanical information, S. racemosa is used in treatment of eye disease, skin diseases, ear diseases, liver and bowel complaints, tumours, uterine disorders, spongy and bleeding gums, asthma, fever, snake-bite, gonorrhoea and arthritis. While S. cochinchinensis is used to heal wounds; treat Kapha disorders, leucorrhoea, stops bleeding, inflammations and swellings, excessive bleeding, asthma, cough, ulcers, arthritis, leucorrhoea, diarrhoea, and skin diseases. Both these plant are accessible in the forest areas of Wayanad district and these are among the NWFPs permitted to collect from the forest. Both these species were present in landslide affected areas and had suffered a major population loss thereby affecting their collection from wild and thus instigating a income loss to forest dwelling communities. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.12. List of Medicinal plants suffered population loss (Cont...)

Sl. No. Species Family 1 Abrus precatorius L. Fabaceae 2 Acacia caesia (L.) Willd. Mimosaceae 3 Acalypha indica L. Euphorbiaceae 4 Achyranthes aspera L. Amaranthaceae 5 Acronychia pedunculata (L.) Miq. Rutaceae 6 Actinodaphne bourdillonii Gamble Lauraceae 7 Ageratum conyzoides L. Asteraceae 8 Ailanthus triphysa (Dennst.) Alston Simaroubaceae 9 Albizia chinensis (Osbeck) Merr. Mimosaceae 10 Albizia odoratissima (L. f.) Benth. Mimosaceae 11 Alstonia scholaris (L.) R. Br. Apocynaceae 12 Ampelocissus latifolia (Roxb.) Planch. Vitaceae 13 Anamirta cocculus (L.) Wight & Arn. Menispermaceae 14 Aphanamixis polystachya (Wall.) Parker Meliaceae 15 Apodytes dimidiata Meyer ex Arn. Icacinaceae 69 16 Areca catechu L. Arecaceae 17 Artocarpus heterophyllus Lam. Moraceae 18 Artocarpus hirsutus Lam. Moraceae 19 Asclepias curassavica L. Asclepiadaceae 20 Asparagus racemosus Willd. Liliaceae 21 Atalantia monophylla (L.) DC. Rutaceae 22 Bidens biternata (Lour.) Merr. & Sheriff Asteraceae 23 Bischofia javanica Blume Euphorbiaceae 24 Boerhavia diffusa L. Nyctaginaceae 25 Bombax ceiba L. Bombacaceae 26 Briedelia stipularis (L.) Blume Euphorbiaceae 27 Caesalpinia mimosoides Lam. Caesalpinaceae 28 Callicarpa tomentosa (L.) Murray Verbenaceae 29 Camellia sinensis (L.) O.Ktze. Theaceae 30 Canarium strictum Roxb. Burseraceae 31 Canscora diffusa (Vahl) R. Br. ex Roem. & Schult. Gentianaceae 32 Carallia brachiata (Lour.) Merr. Rhizophoraceae 33 Cardamine hirsuta L. Brassicaceae 34 Careya arborea Roxb. Lecythidaceae 35 Caryota urens L. Arecaceae 36 Cassine paniculata (Wight & Arn.) Lobr.-Callen Celastraceae 37 Cayratia trifolia (L.) Domin Vitaceae 38 Chassalia curviflora (Wall. ex Kurz) Thw. var. ophioxyloides (Wall.) Rubiaceae Deb & Krishna 39 Chukrasia tabularis A. Juss. Meliaceae 40 Cinnamomum malabatrum (Burm. f.) Blume Lauraceae 41 Cissampelos pareira L. var. hirsuta (Ham. ex DC.) Forman Menispermaceae 42 Clematis gouriana Roxb. ex DC. Ranunculaceae 43 Clerodendrum infortunatum L. Verbenaceae

RESULTS

Table 4.12. List of Medicinal plants suffered population loss (Cont...)

Sl. No. Species Family 44 Coffea arabica L. Rubiaceae 45 Colebrookea oppositifolia Smith Lamiaceae 46 Crassocephalum crepidioides (Benth.) S. Moore Asteraceae 47 Crotalaria spectabilis Roth Fabaceae 48 Curculigo orchioides Gaertn. Hypoxidaceae 49 Cyclea peltata (Lam.) Hook. f. & Thoms. Menispermaceae 50 Cymbidium aloifolium (L.) Sw. Orchidaceae 51 Cymbopogon flexuosus (Nees ex Steud.) Wats. Poaceae 52 Cyperus rotundus L. Cyperaceae 53 Dalbergia latifolia Roxb. Fabaceae 54 Dendrophthoe falcata (L. f.) Etting. Loranthaceae 55 Dichrocephala integrifolia (L. f.) O. Ktze. Asteraceae 56 Dillenia indica L. Dillineaceae 57 Dioscorea oppositifolia L. Dioscoreaceae 70 58 Diploclisia glaucescens (Blume)Diels Menispermaceae 59 Diplocyclos palmatus (L.) Jeffrey Cucurbitaceae 60 Dipterocarpus indicus Bedd. Dipterocarpaceae 61 Drymaria cordata (L.) Willd. ex Roem. & Schult. ssp. diandra Caryophyllaceae (Blume) Duke 62 Dysoxylum malabaricum Bedd. ex Hiern Meliaceae 63 Elaeagnus kologa Schult. Elaeagnaceae 64 Elaeocarpus tuberculatus Roxb. Elaeocarpaceae 65 Elaeocarpus variabilis Zmarzty Elaeocarpaceae 66 Elettaria cardamomum (L.) Maton Zingiberaceae 67 Embelia ribes Burm. f. Myrsinaceae 68 Emilia sonchifolia (L.) DC. Asteraceae 69 Entada rheedei Spreng. Mimosaceae 70 Erythrina stricta Roxb. Fabaceae 71 Euphorbia hirta L. Euphorbiaceae 72 Exacum tetragonum Roxb. Gentianaceae 73 Ficus racemosa L. Moraceae 74 Flacourtia montana Graham Flacoutiaceae 75 Flemingia strobilifera (L.) R. Br. ex Ait.f. Fabaceae 76 Floscopa scandens Lour. Commelinaceae 77 Garcinia cowa Roxb. ex DC. Clusiaceae 78 Garcinia gummi-gutta (L.) Robs. Clusiaceae 79 Garcinia morella (Gaertn.) Desv. Clusiaceae 80 Garcinia rubro-echinata Kosterm. Clusiaceae 81 Glycosmis pentaphylla (Retz.) DC. Rutaceae 82 Gmelina arborea Roxb. Verbenaceae 83 Gnidia glauca (Fresen.) Gilg Thymeleaceae 84 Gomphandra coriacea Wight Icacinaceae 85 Grewia tiliifolia Vahl Tiliaceae 86 Helicteres isora L. Sterculiaceae

IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.12. List of Medicinal plants suffered population loss (Cont...)

Sl. No. Species Family 87 Heliotropium indicum L. Boraginaceae 88 Hellenia speciosa (J. Koenig) Govaerts Costaceae 89 Hemidesmus indicus (L.) R. Br. Asclepiadaceae 90 Heteropogon contortus (L.) P. Beauv. ex Roem. & Schult. Poaceae 91 Hibiscus hispidissimus Griff. Malvaceae 92 Holigarna arnottiana Hook. f. Anacardiaceae 93 Homonoia riparia Lour. Euphorbiaceae 94 Hydnocarpus pentandra (Buch.-Ham.) Oken Flacourtiaceae 95 Hyptis suaveolens (L.) Poit. Lamiaceae 96 Imperata cylindrica (L.) Raeusch. Poaceae 97 Ipomoea hederifolia L. Convolvulaceae 98 Kingiodendron pinnatum (Roxb. ex DC.) Harms Caesalpinaceae 99 Kydia calycina Roxb. Malvaceae 100 Kyllinga brevifolia Rottb. Cyperaceae 101 Lagerstroemia microcarpa Wight Lythraceae 71 102 Lantana camara L. Verbenaceae 103 Laportea interrupta (L.) Chew Urticaceae 104 Leea asiatica (L.) Ridsd. Leeaceae 105 Lobelia nicotianifolia Roth ex Roem. & Schult. Lobeliaceae 106 Luffa cylindrica (L.) Roem. Cucurbitaceae 107 Luvunga eleutherandra Dalz. Rutaceae 108 Macaranga indica Wight Euphorbiaceae 109 Macaranga peltata (Roxb.) Muell.-Arg. Euphorbiaceae 110 Maesa indica (Roxb.) DC. Myrsinaceae 111 Mallotus philippensis (Lam.) Muell.-Arg. Euphorbiaceae 112 Mallotus tetracoccus (Roxb.) Kurz Euphorbiaceae 113 Malvastrum coromandelianum (L.) Garcke Malvaceae 114 Mangifera indica L. Anacardiaceae 115 Melastoma malabathricum L. Melastomataceae 116 Melia azedarach L. Meliaceae 117 Melicope lunu-ankenda (Gaertn.) Hartley Rutaceae 118 Melochia corchorifolia L. Sterculiaceae 119 Memecylon randerianum SM & MR Almeida Melastomataceae 120 Memecylon umbellatum Burm.f. Melastomataceae 121 Merremia vitifolia (Burm. f.) Hall. f. Convolvulaceae 122 Mesua ferrea L. Clusiaceae 123 Mimosa pudica L. Mimosaceae 124 Mitragyna tubulosa (Arn.) Hav. Rubiaceae 125 Murraya paniculata (L.) Jack. Rutaceae 126 Myxopyrum smilacifolium (Wall.) Blume Oleaceae 127 Naravelia zeylanica (L.) DC. Ranunculaceae 128 Naregamia alata Wight & Arn. Meliaceae 129 Naringi crenulata (Roxb.) Nicolson Rutaceae 130 Neolitsea cassia (L.) Kosterm. Lauraceae 131 Ochreinauclea missionis (Wall. ex G. Don) Ridsd. Rubiaceae RESULTS

Table 4.12. List of Medicinal plants suffered population loss (Cont...)

Sl. No. Species Family 130 Neolitsea cassia (L.) Kosterm. Lauraceae 131 Ochreinauclea missionis (Wall. ex G. Don) Ridsd. Rubiaceae 132 Olea dioica Roxb. Oleaceae 133 Ophiorrhiza mungos L. Rubiaceae 134 Oxalis corniculata L. Oxalidaceae 135 Paspalum conjugatum Berg. Poaceae 136 Passiflora foetida L. Passifloraceae 137 Persea macrantha (Nees) Kosterm. Lauraceae 138 Phoebe lanceolata Nees Lauraceae 139 Phyllanthus emblica L. Euphorbiaceae 140 Physalis angulata L. Solanaceae 141 Piper longum L. Piperaceae 142 Piper nigrum L. Piperaceae 143 Pittosporum tetraspermum Wight & Arn. Pittosporaceae 72 144 Poeciloneuron indicum Bedd. Clusiaceae 145 Pogostemon purpurascens Dalz. Lamiaceae 146 Polycarpon prostratum (Forssk.) Asch. & Sehweinf. Caryophyllaceae 147 Pongamia pinnata (L.) Pierre Fabaceae 148 Portulaca oleracea L. Portulacaceae 149 Pothos scandens L. Araceae 150 Prunus ceylanica (Wight) Miq. Rosaceae 151 Pseudarthria viscida (L.) Wight & Arn. Fabaceae 152 Pterocarpus marsupium Roxb. Fabaceae 153 Pterygota alata (Roxb.) R. Br. Sterculiaceae 154 Pueraria tuberosa (Roxb. ex Willd.) DC. Fabaceae 155 Quassia indica (Gaertn.) Nooteb. Simaroubaceae 156 Rauvolfia verticillata (Lour.) Baill. Apocynaceae 157 Rhaphidophora pertusa (Roxb.) Schott Araceae 158 Rorippa indica (L.) Hiern. Brassicaceae 159 Rubia cordifolia L. Rubiaceae 160 Salix tetrasperma Roxb. Salicaceae 161 Sarcandra chloranthoides Gard. Chloranthaceae 162 Schefflera venulosa (Wight & Arn.) Harms Araliaceae 163 Schleichera oleosa (Lour.) Oken Sapindaceae 164 Scleria lithosperma (L.) Sw. Cyperaceae 165 Sida rhombifolia L. Malvaceae 166 Sigesbeckia orientalis L. Asteraceae 167 Solanum aculeatissimum Jacq. Solanaceae 168 Solanum torvum Sw. Solanaceae 169 Spondias pinnata (L. f.) Kurz Anacardiaceae 170 Stereospermum colais (Buch.-Ham. ex Dillw.) Mabb. Bignoniaceae 171 Strobilanthes ciliatus Nees Acanthaceae 172 Strychnos colubrina L. Loganiaceae

IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.12. List of Medicinal plants suffered population loss

Sl. No. Species Family 173 Swertia lawii (Wight ex Clarke) Burkill Gentianaceae 174 Symplocos cochinchinensis (Lour.) Moore ssp. laurina (Retz.) Nooteb. Symplocaceae 175 Symplocos racemosa Roxb. Symplocaceae 176 Syzygium caryophyllatum (L.) Alston Myrtaceae 177 Syzygium cumini (L.) Skeels Myrtaceae 178 Syzygium jambos (L.) Alston Myrtaceae 179 Tabernaemontana alternifolia L. Apocynaceae 180 Tamarindus indica L. Caesalpinaceae 181 Tectona grandis L. Verbenaceae 182 Tephrosia purpurea (L.) Pers. Fabaceae 183 Terminalia bellirica (Gaertn.) Roxb. Combretaceae 184 Terminalia paniculata Roth Combretaceae 185 Thottea siliquosa (Lam.) Ding Hou Aristolochiaceae 186 Thunbergia mysorensis (Wight) Anders. Acanthaceae 187 Tinospora cordifolia (Willd.) Miers. Menispermaceae 73 188 Toddalia asiatica (L.) Lam. Rutaceae 189 Toona ciliata Roem. Meliaceae 190 Trema orientalis (L.) Blume Ulmaceae 191 Trichilia connaroides (Wight & Arn.) Bentv. Meliaceae 192 Turraea villosa Bennett Meliaceae 193 Urena lobata L. Malvaceae 194 Vateria indica L. Dipterocarpaceae 195 Vitex pinnata L. Verbenaceae 196 Waltheria indica L. Sterculiaceae 197 Wrightia tinctoria (Roxb.) R. Br. Apocynaceae 198 Xylia xylocarpa (Roxb.) Taub. Mimosaceae 199 Zanthoxylum rhetsa (Roxb.) DC. Rutaceae 200 Ziziphus rugosa Lam. Rhamnaceae

RESULTS

Table 4.13. List of Invasive species found in the landslide affected areas (Cont...)

Sl. No. Species Family Habit Distribution 1 Acalypha indica L. Euphorbiaceae Herb Indo-Malesia and Tropical Africa 2 Ageratina adenophora (Spreng.) Asteraceae Herb South America King & Robins. 3 Ageratum conyzoides L. Asteraceae Herb Pantropical 4 Ageratum houstonianum Mill. Asteraceae Herb Native of Tropical America; now naturalised in Tropical Asia 5 Alloteropsis cimicina (L.) Stapf Poaceae Herb Paleotropics 6 Alternanthera bettzickiana Amaranthaceae Herb Native of Tropical America; now (Regel) Voss getting naturalised in Asia 7 Alternanthera pungens Kunth Amaranthaceae Herb Native of American; now wide spread as a weed in the tropics and subtropics 8 Bidens biternata (Lour.) Merr. Asteraceae Herb Native of Tropical Africa; Indo- & Sheriff Malesia to Australia 9 Blumea laevis (Lour.) Merr. Asteraceae Herb Indo-Malesia 10 Brachiaria ramosa (L.) Stapf Poaceae Herb Africa and Tropical Asia 74 11 Chloris barbata Sw. Poaceae Herb Native of Tropical Africa, spread to other tropical countries 12 Chromolaena odorata (L.) King Asteraceae Shrub Native of America; naturalised in & H. Rob. Tropical Asia 13 Chrysopogon aciculatus (Retz.) Poaceae Herb Tropical Asia and Australia Trin. 14 Crassocephalum crepioides Asteraceae Herb India, Sri Lanka, China, Africa (Benth.) S. Moore and Madagascar 15 Croton bonplandianus Baill. Euphorbiaceae Herb Native of South America; now naturalised in Paleotropics 16 Cyperus castaneus Willd. Cyperaceae Herb Indo-Malesia to Northern Australia 17 Cyperus iria L. Cyperaceae Herb Tropical Asia and East Africa; introduced in U.S.A and West Indies 18 Cyperus maderaspatanus Willd. Cyperaceae Herb India, Sri Lanka and Tropical Africa 19 Cyperus zollingeri Steud. Cyperaceae Herb Tropical Africa, Madagascar, Malesia and Northern Australia 20 Digitaria ciliaris (Retz.) Koeler Poaceae Herb Paleotropics 21 Eleutheranthera ruderalis (Sw.) Asteraceae Herb Native of Tropical America; now Sch.-Bip. established in several Asian countries 22 Euphorbia heterophylla L. Euphorbiaceae Herb Native of Central America; now a Pantropical weed 23 Euphorbia hirta L. Euphorbiaceae Herb Native of Central America; now a Pantropical weed 24 Fimbristylis dichotoma (L.) Vahl Cyperaceae Herb Tropical Asia 25 Fimbristylis dura (Zoll. & Cyperaceae Herb Indo-Malesia Moritz.) Merr. 26 Hypoestes sanguinolenta Hook. Acanthaceae Herb Native of Madagascar 27 Hyptis capitata Jacq. Lamiaceae Subshrub Native of Tropical America; naturalised in some parts of India and Malesia

IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Table 4.13. List of Invasive species found in the landslide affected areas

Sl. No. Species Family Habit Distribution 27 Hyptis capitata Jacq. Lamiaceae Subshrub Native of Tropical America; naturalised in some parts of India and Malesia 28 Hyptis suaveolens (L.) Poit. Lamiaceae Subshrub Native of Tropical America; naturalised in some parts of India and Malesia 29 Ipomoea hederifolia L. Convolvulaceae Twining Native of Tropical America; now herb naturalised in Tropical Asia 30 Ipomoea purpurea (L.) Roth Convolvulaceae Climber Native of Tropical America; now naturalised in Tropical Asia 31 Ipomoea triloba L. Convolvulaceae Climber Native of Tropical America; now throughout the tropics 32 Kyllinga nemoralis (J. R & G. Cyperaceae Herb Pantropical Forst.) Dandy ex Hutch. & Dalz. 33 Lantana camara L. Verbenaceae Shrub Native of Tropical America, widely naturalised in the tropics 75 and subtropics 34 Mikania micrantha Kunth Asteraceae Climber Pantropical 35 Mimosa pudica L. Mimosaceae Herb Native of South America; now Pantropical 36 Pennisetum polystachyon (L.) Poaceae Herb Paleotropics Schult. 37 Pseudanthistiria umbellata Poaceae Herb Peninsular India and Sri Lanka (Hack.) Hook. f., 38 Pteridium revolutum (Blume) Dennstaedtiacae Shrub Tropical and sub-tropical Asia Nakai and Australia 39 Sphagneticola trilobata (L.) Asteraceae Herb Indo-Malesia Pruski 40 Spilanthes radicans Jacq. Asteraceae Herb Neotropics of the world; now naturalised in Western Peninsular India 41 Sporobolus tenuissimus Poaceae Herb Pantropical (Schrank) O. Ktze. 42 Stachytarpheta cayennensis Verbenaceae Shrub Native of Tropical America; now (Rich.) Schauer introduced into tropics and subtropics 43 Stachytarpheta jamaicensis (L.) Verbenaceae Shrub Native of Tropical America; now Vahl introduced into tropics and subtropics 44 Synedrella nodiflora (L.) Gaertn. Asteraceae Herb Native of West Indies; naturalised in India, China, Malesia and Polynesia 45 Tridax procumbens L. Asteraceae Herb Native of Tropical America; now widespread throughout tropics and subtropics

RESULTS

Phenological Changes

Phyllanthus emblica L. Toddalia asiatica (L.) Lam.

Wendlandia thyrsoidea (Schult.) Steud. There was an observed change in the flowering phenology of several species in higher altitudes. Some species like Phyllanthus emblica L., Toddalia asiatica (L.) Lam., Wendlandia thyrsoidea (Schult.) Steud., Ziziphus rugosa Lam. etc. showed a delay in the onset of flowering. While some others like Cinnamomum sulphuratum Nees, Diospyros nilagirica Bedd., Elaeocarpus variabilis Zmarzty etc. showed early flowering. It is not clear whether we can correlate the change in phenology with the Ziziphus rugosa Lam. extreme rainfall and subsequent increase in the temperature. We need continuous observations to understand how the plants are responding to climate change in this region. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

4.5. Resilient Taxa As the landslide involves mass movement of topsoil, in the areas where these events occurred none of the species is resilient. Spatially there is a heterogeneous removal of both substrate and vegetation. Landslides often lead to a unique succession direction because the existing vegetation, seed bank and top soil including nutrient and mycorrhizal inoculum have been lost.

4.6. Impact on livelihood A livelihood is a means of making a living. It encompasses people’s capabilities, assets, income and activities required to secure the necessities of life. It is acknowledged that income in rural developing regions is highly dependent on human, social and physical capital available to the household (Deaton, 1997). Human and social capital include education, experience, status and access to social networks. Physical capital includes the availability of cultivable land, climate and other productive assets. In contrast to direct impacts, off-site impacts refer to all consequences landslides may have outside the exact spot of their occurrence (Alimohammadlou et al., 2013). Landslides may, for example, decrease the means of transport by cutting off roads or they may cause floods and excessive sediment deposition by temporarily damming rivers, thereby indirectly affecting household income (e.g. Claessens et al., 2007; De Haen & Hemrich, 2007; Meyer et al., 2013). While critical infrastructure is limited in our study area, the indirect effects of 77 landslides can still potentially decrease the income of the households at an aggregated geographical level A second indirect consequence of landslides is related to landslide risk. When directly affecting a household’s house or plots, landslides often destroy crops and productive assets, essentially soil quality and livestock, and thereby cause a shock. The income from agriculture will be reduced and, in case insufficient alternative income sources are found, also total income will be affected. The surveys conducted as part of ‘Rebuild Kerala’ has shown that about 36.74% of the net cropped area of Wayanad was damaged during the catastrophic events in 2018. Perennial and annual crops, such as bananas, coconuts, areca nut, pepper, and coffee were the most impacted. Seasonal crops, such as rice, vegetable, tapioca, and other tuber crops also suffered significant losses (PDNA, 2018). When we look in the context of landslides occurred in the forest areas of the district, most landslides are relatively small and local, causing idiosyncratic shocks which only affect a few plots at the same time. However there were stronger impacts due to major landslides. In Kurichiyarmala 4 houses were fully wiped out in the debris flow due to the landslide in the forest. It also damaged a vast area of a tea estate and plantation of local people. A school which facilitated education for the children of those working in the estate and other adjacent families suffered serious damage due to the dumping of runoff soil and the building is now abandoned. Another 5 houses sustained damages in Ammara due to a landslide in forest margin. In Sugandhagiri Anpathu-acre region 3 houses were totally damaged due to separate landslide events. The area forms part of land which has been given to forest dependant communities as part of Forest Rights Act 2006. In this region a lot of plantations crops have been damaged due to landslides. The slides occurred along the forest border in Parathode region also sustained asset loss to some families. The slides occurred in Muthumari, Maniyankunnu, Pancharakolli, Kambamala, Ambalamoola had also sustained a direct loss to the assets and crop lands of people living close to the forest. The runoff from landslides occurred at Muthumari and Pancharakolli had irrecoverably damaged acres of paddy and other perennial crops. 4.7. Immediate impact of disaster as top soil loss Landslides changed soil properties in major landslide affected areas like Kurichiyarmala, slides in Ladies Smith reserve forest, Pancharakolli, Maniyankunnu, Andikunnu (43 mile), Kambamala, Kurisukuthi, Sooryamudi, Muthumari, Thacharakolli, Priyadarshini, Panamkuzhi, Sugandhagiri and Kurichiyarmala primarily by exposing parent material (the C horizon) by removing organic mats H, O and A horizons (FAO Soil Classification), thus resetting the pedogenic clock to the initial stages. H horizons are layers RESULTS

of organic material having a certain minimum content of soil organic carbon. In the World Reference Base for Soil Resources (WRB), this is 20% (by weight). This layer is formed from organic residues that are not incorporated into the mineral soil. O horizon or the organic layer is defined by having a certain minimum content of soil organic carbon. In the WRB, this is 20% (by weight). The O horizon is formed from organic residues that are not incorporated into the mineral soil. The residues may be partially altered by decomposition, which includes leaves, twigs, moss, lichens, etc. The upper part of the landslide (in the area referred to as the landslide niche) is strongly eroded and characterised by the least advanced soil cover recovery. Additionally, low soil organic matter content was observed in the upper part of the landslide. Normally, one tonne soil, comprising half cubic metre soil, has around 5kg of organic matter and it helps the soil retain around 50 litres of water. Priliminary studies by soil department showed that landslides and floods have flushed out the organic content and humus from the soil in many areas thereby reducing its water holding capacity and also resulted in increase of soil temperature. The average depth of scar (from the main scarp downwards) in all these areas is 30–70 m and the distance from toe to main scarp is between 500–2000 m. The width near the main scarp ranges from 8–78 m which narrows towards the toe. Initial estimates show that an average of 10 lakh cubic metres of top soil has been displaced. It is difficult to get the exact amount of top soil displacement by ground survey alone and for 78 a better assessment of top soil displacement, Interferometric synthetic aperture radar (InSAR) techniques should be used which allows mapping of ground movement that occurs between two acquisition times (Hanssen, 2001) as the relief profile of the study area shows a gently sloping morphology.

4.8. Long-term modification in ecosystems/microhabitats According to the survey to date, it is estimated that a total of 50 hectare forest area has been degraded due to landslides and slips. Debris flow wiped out vegetation and wildlife in its path. This has also affected the soil seed bank of this region and the soil microbiota favouring germination and establishment of seedlings. Debris flow has uprooted several large trees causing opening of the closed canopies inducing a gap effect. When one or a few canopy trees die (or are injured) in a forest small openings, which are called ‘gaps,’ are formed in the forest canopy and are then filled with other trees. The ‘gap dynamics theory’ (or simply, gap theory) predicts a scenario; shade-intolerant species can maintain their populations by regenerating within gaps in the mature or old-growth forests (Watt, 1947; Whitmore, 1975). The gaps created thus provide microenvironmental conditions (light, moisture or temperature), favouring the establishment of shade- intolerant species. Studies have shown that the majority of the climax species found in the Western Ghats are having recalcitrant seeds. Adding to this since some slides are close to forest margins, there is an increased chance of establishment of invasive species which is already evident as we could identify the presence of 45 species which are known for their invasive nature and this could suppress the establishment of other species. Many invasive species are considered competitively superior to native species, with the strongest competition expected in species with similar niches and/or in closely related species. This, along with the loss of the soil seed bank, favours pioneer species. Each tree can be considered an ecosystem considering the number of other species dependent on it and the loss of a single one will affect uncounted number of organisms. The landslides caused severe damage to the forest by removing topsoil, blocking springs and increasing downstream sedimentation. Several 3rd and 4th order streams (Hack’s stream order or Gravelius’ stream order) in Vythiri mountain belt and Makkimala—Tirunelli belt where severely damaged. Further long-term community level studies are required for understanding the effects of each individual event. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

4.9. Impact on biodiversity Landslides are closely related to loss of biodiversity. According to Crozier (1986), landslides are a product of their environment and in return they also influence their environment. The mass movements generated a total transformation of the natural environment in the area of their occurrence. On slope surfaces damaged and transformed by mass movements, diversified morphology is formed with concave and convex landforms, often with bedrock expositions in the landslides occurred at Lady Smith reserve forest. Moreover, a new system of water circulation and specific pedogenetical conditions are formed in major landslides. As the effect of gravitational transformations of the substratum, a mosaic of diversified, natural small-sized habitats develop. In all sites, landslides have become a major threat to biodiversity as they cause significant loss of flora and fauna. Loss of vegetation due to flora was evident, but it found no conclusive evidence of loss of large animals. Based on Phytosociological evidences, it was concluded that about 376 angiosperm taxa and 21 pteridophyte species succumbed population loss due to the landslide events in the forest areas of Wayanad district. Biodiversity comprises elements other than single species, such as the interactions between species and their stability over time and space. These sometimes overlooked properties are key to the functioning of ecosystems. They are the missed component of biodiversity loss that accompanies or precedes species extinctions. Irrespective of a positive, negative or neutral change in local diversity, spatial patterns of habitat loss largely influence the structure and dynamics of biodiversity. Long-term observations are needed to 79 understand the impact of landslides in biodiversity at both micro and macro habitat levels. RESULTS

80 IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

ENVIRONMENTAL IMPACT 5

5.1. Environmental Costs of Landslides

Landslides occur throughout the world, and especially in certain hotspots (Nadim et al., 2006). Much has been written about landslide impacts on human lives and on infrastructure. Little attention, however, has been paid to landslide impacts on the natural environment (Schuster & Highland, 2007). Even less consideration has been given to the role that landslides play in disturbance ecology (Geertsema & Pojar, 2007). Landslides can wipe out large tracts of forest, destroy wildlife habitat, and remove productive soils from slopes. There is a continuum between the socioeconomic costs of landslides and the environmental costs of landslides. This is because a healthy environment is important for sustaining human populations. Where a landslide causes a loss of resources by destroying farmland or forest, deposits sediment into a stream, or pollutes a drinking water source, the environmental impacts have attained a socioeconomic dimension 81 (Geertsema et al., 2009). The total area under forests in Wayanad is 787 square kilometers. The landslides that occurred inside the forest have degraded ca. 50 hectares of area, leading to a loss of this much forest cover, which accounts for 0.064% of the total forest area. Wayanad is known for the high amount of rain received during the monsoon period, and about 25% of the total terrain is having a high risk of landslides. During the survey it could be noted that there were prior instances of landslides inside the forest as evident from the scars left. Population loss was observed for 376 angiosperm taxa and 21 pteridophyte species. In places like, Kurisukuthi, Maniyankunnu, Kambamala, Muthumari large evergreen patches have been damaged there by effecting the microhabitat conditions in these regions. The landslides resulted in gap formation, which causes changes in microenvironment and community dynamics. Larger gaps raise the probability of taking over of shade-intolerant species and the spread of invasive species. Fissures in earth and cases of land subsidence where seen in Bhrahmagiri, Plamoola, Priyadarshini forest areas. Landslides in Brahmagiri, Peedikapullu, Sooryamudi had also affected the grasslands as these occurred in the confluence of forest and grassland. Soil-stripping by landslides largely reduces the productivity of forests Landslide size and type play a role in impacts on streams. Noticeably, the size of the landslide in relation to the size of the stream is important. In major landslide hit areas like Peedikapullu, Panamkunduchal, Arikallammottamchal, Muthumari, Kambamala slumps and earth flows caused low-level, long-term contributions of sediment and large woody debris to channels; partial channel blockages; local channel constriction below the point of landslide entry; and shifts in channel configuration. It also led to the closure of several springs. There are several perennial springs being tapped for community and panchayat run drinking water projects. Some of these have been severely affected in areas like Lady Smith reserve forest, Thacharakolli, Tirunelli etc. An overlay of the co-ordinates of the sites where landslides and slips occurred over Drainage density map of the Wayanad district created using a 30 m DEM corrected using 30 m resolution LANDSAT image and stream network map shows the impact of Landslides on the drainage network of the district particularly the first and second order streams (Fig. 5.1 & 5.2). ENVIRONMENTAL IMPACT

Figure 5.1. Landslide sites overlaid on Stream Network Map of Wayanad

Figure 5.2. Landslide sites overlaid on Drainage Density Map of Wayanad IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

SOCIO ECONOMIC IMPACT 6

Social and economic losses, and their quantification, the consequences of landslides on infrastructure development, and land use policy, are critical aspects of socioeconomic issues related to landslides. Reliable numbers for the socio economic impact from landslides are difficult to obtain mainly because the landslide hazard assessment is often merged with other associated natural disasters such as flooding, meteorological events such as Cyclones. Landslides are one of the most widespread hazards on Earth and cause thousands of deaths and injuries and billions of dollars in damage worldwide each year (Kjekstad & Highland, 2009). Statistics from The Centre for Research on the Epidemiology of Disasters (CRED, http://www.cred.be/) show that landslides contribute to about 17% of fatalities due to natural hazards. Many papers have been written on the socioeconomic impacts of landslides on the built environment. However, relatively few studies have 83 discussed the effects of landslides on the natural environment, i.e., on (1) the morphology of both subaerial and submarine surfaces of the Earth, (2) the natural forests and grasslands that cover much of the Earth’s surface, (3) quality of streams and other bodies of water, and (4) the habitats of native fauna, both on the Earth’s surface and in its streams and oceans. Direct costs are the repair, replacement, or maintenance resulting from damage to property or installations within the boundaries of the responsible landslides or from landslide-caused flooding. All other costs of landslides are indirect. Landslide events were reported only from Wayanad North and South Division and as per the data available with the forest department, the North and South forest divisions sustained the following loss due to the landslides and associated events; Around 28.8 km fencing has been irrecoverably damaged with an estimated loss of ₹ 40 lakhs; A total of 99 cairns were lost, which counts to ₹ 6.93 lakhs; Even though the loss due to forest cover is nontangible, a preliminary evaluation of ₹ 393 lakhs was estimated. An estimated loss of ₹ 3.6 crore, as per the net per cent value of the forestland as assessed by the department, was incurred in the calamities. The ecotourism programmes of these divisions suffered an appraised loss of ₹ 53.5 lakhs. The landslides and associated debris flow resulted in quite a lot of loss to private properties. Four houses were fully wiped in Kurichiyarmala due to the landslide in the forest. This slide also sustained damages to a vast area of a tea estate and plantation of people leaving close to the forest. A school that facilitated education for the children of those working in the estate and other adjacent families was abandoned due to the dumping of runoff soil. Another landslide in Ammara in the forest margin damaged four houses. Separate landslide events in Sugandhagiri Anpathu-acre region wrecked three houses in the area given to forest dependent communities as part of the Forest Rights Act 2006. In this region, many plantation crops have been damaged due to landslides. The slides that occurred along the forest border in Parathode region also sustained asset loss to some families. The slides occurred in Muthumari, Maniyankunnu, Pancharakolli, Kambamala, Ambalamoola had also sustained a direct loss to the assets in the form of buildings and acres of agriculture land of people living close to the forest. Total loss of agriculture in Wayanad is tentatively estimated as ₹101895.4 lakh (CTCRI, 2018). A comprehensive economic assessment is needed to assess both the direct and indirect losses, including lost future production on arable land covered by landslide debris, unusable barren land, and lost recreational revenues direct costs associated with compensation for loss of life, structures, and livestock, and less tangible, but important damages, such as interruptions in local transit, decreased quality of life, and impaired water quality, as well as cost of rescue efforts, should be considered. SOCIOECONOMIC IMPACT

84 IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

DISCUSSION AND CONCLUSION 7

Landslides affect the following elements of the environment: topography of earth’s surface, character and quality of rivers and streams and ground water flow, forest that cover the earth and habitats of natural wildlife. Large amount of soil and organic materials enter the streams as sediments because of this landslide and erosion activity. Wayanad district experienced the highest rainfall during the month of May–August with 33, 126, 160 and 142% increase respectively over the previous year. For a understanding of spatial distribution of rain across the district, long period of record of precipitation estimates based on infrared Cloud Cloud Direction (CCD) observations was used to create gridded rainfall trend (Fig. 4.7). It has been observed that the areas around Lakkidi, Vythiri, Vellaramkunnu, Pozhuthana, Koroth, Arimala and Periya experiences the highest rainfall of 3,322.96–3,774.33 mm. The eastern parts of the district experiences comparatively low rainfall in 85 the range 1,823.48–2,274.85. The major landslide affected areas correlates with the spatial distribution of rainfall over the district. The rainfall data from four IMD stations in Wayanad shows that during June and July Vythiri recorded the highest amount of rainfall with 1380.5 mm and 1500 mm over last years 646.2mm and 565.7mm respectively. Mananthavady recorded 1420.6mm during August higher than 1294.6mm recorded in Vythiri (Fig.4.6). According to the data available with District Soil Conservation Office, in Wayanad 242 land subsidence and landslip cases were reported in the district and the instances in forests were not reckoned. The team had surveyed the forest areas from December 2018 to March 2019 for inventorying the slope movements occurred inside the forest and the associated loss of angiosperms and pteridophytes. As part of the survey we had identified 60 major and 56 minor slope movements. Of the major instances, 13 are transitional planar earth slide and 4 are complex: part rotational, part transitional type following Cruden and Varness (1996). The most number of slope movements occurred in Wayanad South division with 64 instances and 51 were recorded in Wayanad North division. 25 appears to be deep seated landslides due to excessive soil water pressure. In both these divisions the slides had caused severe species loss and degrading over 50 hectares of forest area. A total of 376 angiosperms and 21 pteridophytes suffered population loss which includes 155 tree species, 200 with known medicinal value and 46 species collected as NWFP. Of the 58 angiosperm species whose conservation status is known, 42 are under low risk categories and the remaining 14 are threatened (Fig. 4.37). Vateria indica L. a critically endangered species suffered major population loss. The other species suffering the most are Aglaia barberi Gamble, Apodytes dimidiata Meyer ex Arn., Bischofia javanica Blume, Canarium strictum Roxb., Cinnamomum malabatrum (Burm. f.) Blume, Elaeocarpus tuberculatus Roxb., Lagerstroemia microcarpa Wight, Macaranga peltata (Roxb.) Muell.-Arg., Olea dioica Roxb., Palaquium ellipticum (Dalz.) Baill., Reinwardtiodendron anamalaiense (Bedd.) Mabb., Schleichera oleosa (Lour.) Oken, Symplocos cochinchinensis ssp. laurina (Retz.) Nooteb., Symplocos racemosa Roxb., etc. These along with other endemics which suffered population loss should be under priority on further recovery and restoration activities. A total of 81 Angiosperm and 4 Pteridophyte species endemic to the Indian mainland suffered population loss. A landslide hazard map describes the possibility of landslides occurring throughout a given area. As part of the study a macro landslide hazard zonation mapping on 1:30,000 scale of Wayanad district was prepared. For which 10 factors: Rainfall distribution, drainage density, Elevation, Slope, Lineament density, Land use, Soil, Landform, TWI and TPI were used. The landslide susceptibility map was derived using weighted overlay method depending on its influence on landslide occurrence and categorized into five susceptibility DISCUSSION AND CONCLUSION

class: very low, low, moderate, high and very high. The results revealed that 7.98 % area is under very high-risk class, 17.99% under high risk class which totals 25.97% equalling to 536.22 km2 land area. An overlay of the inventory of landslide locations prepared by field survey showed a 100% correlation, as they occurred in these classes. A panchayat level analysis showed that more than 70% area of Meppadi, Vythiri, Pozhuthana, Thariyode, Padinjarathara, Thondernadu and 50% area of Thavinjal and Tirunelli falls under very high- and high-risk zones. The incidences of landslides can be grouped topographically into two areas—Vythiri mountain belt and Makkimala belt, which have areas with inherently unstable slopes. Even though the natural disaster caused by intense rain was a short duration event it has caused a severe damage leaving a long-lasting impact. The study has only assessed the impact of landslides on the forest ecosystems and the impact of flood in low lying areas including wetlands needs to be assessed to get a comprehensive account on the species loss sustained. It has been estimated that habitat and population of 397 species of angiosperms and pteridophytes have been affected in disaster hit habitats. However, the impact on the seasonal plants is not known. The district is known for the presence of point endemics which increases the concerns and warrants further observations. Most of the species in Western Ghats are extremely habitat specific and adopted to unique high-altitude micro-climate. About 81 species endemic to south Western Ghats has suffered habitat and population loss. The best way to its successful conservation is in situ protection within natural habitat. Every single region 86 in this district with a signature physiography has unique trend, aspect and drainage creating differential microhabitats thus supporting unique floristic composition. It has been noted that the floristic composition in Vythiri belt is different from that in Makkimala belt. With the loss of any part of these unique regions, we may not necessarily lose a species, but certainly lose unique microhabitats of micro ecosystems with differential composition. Around 45 invasive species were recorded from landslide hit areas. As evident from earlier studies landslide will change the microhabitat condition to such an extent that it mostly suites the spread of invasive species. The complete removal of topsoil on stabilized slopes will affect new growth and survival. As a rule, species from adjacent slopes will try to cover newly created areas, which are completely exposed and seldom vulnerable to further soil displacement and offers little or nil scope for plant growth, especially specialized species flourishing in top soil enriched with nutrients. The changing climatic regime favours invasive species which survives with comparatively less nutrient requirements and will invade first in these open areas affecting the forest composition and survival and establishment of other specialized species. A close monitoring is required to prevent their invasion and assisted regeneration should be adopted to recover the affected areas so that the composition should be similar to the situation before the event. Wayanad has a unique topography and microclimatic condition as it is evident from its rich biodiversity. About 2034 species of angiosperms are known from the region with 29% endemics. The district is also rich in pteridophyte diversity with 163 species including 19 endemics. The high degree of endemism reflects the uniqueness of this region. It is necessary to assess the loss of biodiversity outside the forested areas to understand the impact of flood on the removal of annual and perennial plants. All the rivers in the district experienced flooding and caused heavy cutting of entire river slopes and causing complete removal of vegetation cover from river banks. The impact may not be critical for those species having broad distribution range, but certainly threatens locally restricted, habitat specific species. It has been noted that the instances of land movements where high on disturbed forest areas than those in undisturbed high altitude forests. Preliminary surveys had showed a change in flowering phenology of some species in the high altitude as a detrimental effect of heavy downpour. Phenological changes at community level should be closely observed to note if the changes are persistent in the coming seasons. Deleterious effect of the pollen washout because of continuous downpour also need to be noted. During this summer the spread of forest fire was found to be double the area than last year which can be due to the change in drainage regime alongside the increase in summer temperature. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

SUGGESTED INTERVENTIONS 8

8.1. Prioritized areas

Every natural disaster is associated with a loss sustaining to properties and human life. Sughandhagiri Anpethu acre region is one of the most affected areas with several landslide events and even resulting in the loss of houses of tribal people in the land given to them under Forest Rights Act 2006. This region comes under high risk zone for landslide susceptibility. It is recommended that any further construction or activities which cause slope destabilization in this region should be avoided and these people living here had better be rehabilitated to more safer areas. The region is highly sensitive and efforts should be taken to increase the canopy cover in this region. Discussions with some of the LSGs have revealed that they are still not aware of the hazard zones under their legislation. Efforts should be taken to map the landslide prone areas of all panchayats in a 1:500 scale which help in spatial planning for avoiding un-sustainable and non-resilient developmental activities. This 87 will also help in developing Ecosystem Based Solutions for the recovery of affected and risk prone areas and reducing further damages in the case of such torrential rain. Wayanad in its present land use scenario is highly prone to natural disasters and immediate attention should be made to assess the change in Land use pattern and to develop strategies to make the area resilient to climate change related events. During the survey scars of landslides occurred during previous years has been noted. A thorough survey has to be taken up to evaluate the forest floor to record events of all land movements particularly in very high and high hazard zones. There are fissures in the forest areas of Lady Smith reserve forest, Brahmagiri Mountains and Makkimala belt. The extent of these fissures, land subsidence etc should be noted. Studies should be taken up to examine the composition of vegetation on hills where landslides occurred and also the differences in the vegetation frequency and cover on landslides on different substrates. As most of the landslides have caused the blockage of first older streams and springs, efforts should be made on priority basis to recover these streams and springs. A detailed survey of the forest areas should be undertaken to understood the impact of the landslides and the continuous downpour on the soil seed bank and regeneration of seasonal plants. The landslide affected areas should be monitored to prevent the spread of invasive species. 8.2. Issues The lack of baseline data on the spatial distribution of species was an issue faced during the survey. The PBRs were found to be lacking information on all the species seen in a LSG particularly the plants in the forests. It is high time to update the PBRs more systematically on grid basis so that it can be used as a ready reference. A 1:1 ground survey should be done to understand the hazard susceptibility zones in each LSGs which will help in BMCs and planners while taking decisions on developmental activities. 8.3. Interventions suggested by BMC/LSG Most of the major landslide affected areas fall under Vythiri, Pozhuthana, Thariyode, Mananthavady, Tirunelli and Thavinjal LSGs. These LSGs and BMCs are not acquainted to suggest any interventions. Mananthavady LSG had informed that they are planning to have a programme to increase species cover with 50% funding from KSBB. But the landslide affected areas in the forests are not there in their priority list for planting. Thavinjal panchayat is planning to plant vetiver in landslide/slip affected areas, which they consider as a supplementary income source for local people after two years. But the uprooting of vetiver from slopes will cause the soil’s loosening leading to erosion. None of the LSGs have programmes to recover landslide affected forest areas. SUGGESTED INTERVENTIONS

8.4. Landscape and Site specific restoration activities Natural ecosystems have an intrinsic drive to recover after natural damage. However, frequent damage of natural ecosystems in various regions in the climate change scenario underlies the need for technologies to speed up the process of recovery. Ecological restoration is undoubtedly the most important factor in improving the effects of severe ecological disturbance such as landslides (Aronson et al., 1993; Rawat et al., 2012, Walker et al., 2007). It is the manipulation of succession to achieve some predetermined goal such as a certain species composition, site fertility or site stability. The European Commission defined NbS as “solutions inspired and supported by nature, designed to address societal challenges which are cost effective, simultaneously provide environmental, social and economic benefits, and help build resilience” (European Commission, 2016; Raymond et al., 2017). Bioengineering, an advanced application is an integrated approach that assists stabilization of hill slopes/ landslide sites and improves the site quality by improving soil nutrient status. This technique is a cost- effective solution and involves the use of living plants and other secondary materials for stabilization of hill slopes which works as an integrated technique to protect slope against surface tension, to reduce the risk of planer sliding and to improve surface draining. Species having colonizing behaviour, fast growing nature and dense and deep root system with the potential of adventitious root system and fast and simple propagation are selected for bioengineering application. 88 Vegetative treatments alone are much less expensive than earth retaining structures or other geological protection systems. Combined structural, vegetative slope protection systems are more cost effective than the use of either vegetation or structure alone at most times (see White, 1979). There are various complementary methods to manage landslide risk, and are applied at two geographic scales: individual slopes within a sub catchment, and upland landscapes ranging in size from sub catchments to entire river basins. For individual slopes, the options are the use of plants, including trees and shrubs, to reduce landslide hazards, or mitigating landslide impacts through site reclamation also using trees and shrubs. At the landscape level, forest-related options include retention and protective forestation which involves rehabilitation or restoration of forest. Retention of intact natural and plantation forests in upland areas is the first and best way to protect uplands from landslides (Gray & Leiser, 1982). At the landscape level, there are several forestation alternatives depending on local ecology and local socio-economic conditions. The options range from assisted natural regeneration and providing protection that allows forest recovery or intervening directly by planting indigenous and/or exotic species. The hydrological and mechanical mechanisms (Table 8.1) by which vegetation influences the slopes according to Greenway (1987) are:

Table 8.1. Hydrological and mechanical mechanisms by which vegetation influences the slopes

Hydrological mechanisms Influence Foliage intercepts rainfall, causing absorptive and evaporative Beneficial for slope stability losses that reduce rainfall available for infiltration Roots and stems increase the roughness of the ground surface Adverse for slope stability and the permeability of the soil, leading to increased infiltration capacity Roots extract moisture from the soil, which is lost to the Beneficial for slope stability atmosphere via transpiration, leading to lower pore water pressure Depletion of soil moisture may accentuate desiccation cracks in Adverse for slope stability the soil, resulting in a higher infiltration capacity Mechanical mechanisms Influence Roots reinforce the soil, increasing soil shear strength in the Beneficial for slope stability same manner as jute/coir netting and reinforcing grids of jute/coir/geo textiles, etc. Tree roots may anchor deep into firm strata, providing support Beneficial for slope stability to the up-slope soil mantle through buttressing and arching. They have similar effect as shear keys & bolts; pre-stressed rock anchors, etc. Tree roots help in soil compaction and in densification and Beneficial for slope stability solidification of earth material in a similar of fashion as timber/concrete/lime piles do Weight of the tress surcharges the slope, increasing normal and Both Adverse and Beneficial downhill force components Vegetation exposed to the wind transmits dynamic forces in to Adverse for slope stability the slope especially where wind velocity is high and during storms Roots bind soil particles together in the surface of the ground, Beneficial for slope stability increasing cohesive and adhesive forces and thereby reducing their susceptibility to erosion and land sliding Vegetation reduces the impact of mechanical and hydraulic Beneficial for slope stability pressure on land (by heavily falling raindrops- mechanical impact reduction, by reducing running water erosion; prevent/reduce toe erosion, etc.)

Hydrological mechanisms Influence Foliage intercepts rainfall, causing absorptive and evaporative Beneficial for slope stability losses that reduce rainfall available for infiltration Roots and stems increase the roughness of the ground surface Adverse for slope stability and the permeability of the soil, leading to increased infiltration capacity Roots extract moisture from the soil, which is lost to the Beneficial for slope stability atmosphere via transpiration, leading to lower pore water pressure IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA Depletion of soil moisture may accentuate desiccation cracks in Adverse for slope stability the soil, resulting in a higher infiltration capacity Mechanical mechanisms Influence Roots reinforce the soil, increasing soil shear strength in the Beneficial for slope stability same manner as jute/coir netting and reinforcing grids of jute/coir/geo textiles, etc. Tree roots may anchor deep into firm strata, providing support Beneficial for slope stability to the up-slope soil mantle through buttressing and arching. They have similar effect as shear keys & bolts; pre-stressed rock anchors, etc. Tree roots help in soil compaction and in densification and Beneficial for slope stability solidification of earth material in a similar of fashion as timber/concrete/lime piles do Weight of the tress surcharges the slope, increasing normal and Both Adverse and Beneficial downhill force components Vegetation exposed to the wind transmits dynamic forces in to Adverse for slope stability the slope especially where wind velocity is high and during storms Roots bind soil particles together in the surface of the ground, Beneficial for slope stability increasing cohesive and adhesive forces and thereby reducing their susceptibility to erosion and land sliding Vegetation reduces the impact of mechanical and hydraulic Beneficial for slope stability pressure on land (by heavily falling raindrops- mechanical impact 89 reduction, by reducing running water erosion; prevent/reduce toe erosion, etc.)

The following widely accepted bioengineering techniques (Singh, 2010; Lange et al., 2018; Zerube & Mencel, 1969) can be adopted to stabilize and recover the landslide affected and susceptible areas. Slope stabilization through contour wattling, mulching and planting: As part of site-specific activity in major landslides, Contour wattling along with mulching and planting is of great help. This technique comprises breaking the length of slope into shorter stable portions by providing contour wattles, mulching the inter wattle area and effective plantation. On the downhill side trench, post of species which sprout on planting such as Lannea coromandelica (Houtt.) Merr., Gliricidia sepium (Jacq.) Kunth ex Walp., etc. are placed in the trenches at 100–125 cm interval. Excavation and fill: These are an important aspect of slope modification. Excavation is the removal of rock and soil from the head of a landslide to reduce the driving force and improve the stability of the landslide. This method is only suitable for rotational landslides. Slope stability can be improved by removing of the entire slide mass, reducing the height of the slope, back filling with lightweight material, constructing benches, flattening the slope angle. The selection of technique should depend on the type of landslide and cost effectiveness. Slope stabilization and erosion control by coir netting or Jute geo-textiles: After grading the slope, the seed are sown, and organic manure is applied. Two sowing are done, one before netting and the other after laying of coir netting. The coir netting is firmly laid on the prepared slopes toward water flow. The toe ends of the coir netting are inserted with a 15 cm loop into the top trench and firmly back filled after driving 10–12 gauge, 20 cm long steel staples (u-nails) at 30 cm intervals. The successive widths of coir netting carpets are secured against displacement by an overlapping of about 8 cm. They are pegged down with staple driven 30 cm apart. Germination of grasses in areas treated with geojute is much better. A combination of local species along with other species is necessary to regenerate the affected area close to its native form. The traditional ecological restoration techniques and even the advanced bioengineering applications both works on a basic theory called “Choice of Species”. The selected species should have deep and large root system and preferably be hardy, fast-growing and suckering (Sastry & Kavathekar, 1990). When properly installed and maintained, vegetation could protect slopes by reducing erosion, strengthening soil, SUGGESTED INTERVENTIONS

and inhibiting landslides which increase general slope stability. The use of vegetation to manage erosion and protect slopes is relatively inexpensive (Rawat et al., 2012). On slopes susceptible to land sliding there is a need to select appropriate species for land stabilization. Species characteristics effective for erosion control are also desirable for the rehabilitation of landslide areas. In general order of importance, they should have (Young, 1997; Evans & Turnbull, 2004):

1. Good survival and growth on poor sites; 2. Ability to produce a large amount of litter; 3. Strong, deep and wide-spreading root system with dense, fibrous roots; 4. Ease of establishment and need for minimal maintenance; 5. Capacity to form a dense crown and to retain foliage year-round, or at least through the rainy season; 6. Resistance to insects, disease, drought and animal browsing; 7. Good capacity for soil improvement, e.g. high rates of nitrogen-fixation, appreciable nutrient content in the root system; 8. Provision of economic returns or service functions (quickly) such as fruit, nuts, fodder, etc.; 9. Absence of toxic substances in litter or root residues; and

90 10. Low invasiveness

Barker (1995), detailed the advantages and disadvantages of various groups of plants for slope reinforcement based on the density of the surface cover they provide, the depths of their roots systems, the cost of installation and of the maintenance required (Table 8.2).

Table 8.2. Suitability of plant types for different engineering functions and applications Type Advantages Disadvantages Grass Versatile and cost effective, wide range of tolerance, Shallow rooting, regular quick to establish, good dense surface cover. maintenance required. Herbs Deeper rooting, attractive in grass sward. Seed expensive, sometimes difficult to establish. Shrubs Robust and cost effective, many species can be seeded, More expensive to plant, substantial ground cover, deeper rooting, low sometimes difficult to establish. maintenance, many evergreen species. Trees Substantial rooting, some can be seeded, no Long time to establish, slow maintenance once established. growing.

Some species which can be used for recovery of landslide affected areas are: Bambusa sps., Bischofia javanica Blume, Callicarpa tomentosa L., Carex baccans Nees, Chrysopogon aciculatus (Retz.) Trin., Chrysopogon zizanioides (L.) Roberty, Crotolaria sps., Cymbopogon citratus (DC.) Stapf, Cymbopogon flexuosus (Nees ex Steud.) Wats., Cymbopogon nardus (L.) Rendle, Cynodon dactylon (L.) Pers., Dalbergia latifolia Roxb., Desmodium sps., Digitaria ciliaris (Retz.) Koelersp., Digitaria longiflora (Retz.) Pers., Diospyros ovalifolia Wight, Ficus sps., Hopea sps., Hypolytrum nemorum (Vahl.) Spreng., Imperata cylindrica (L.) Raeusch., Ochlandra sps., Mallotus tetracoccus (Roxb.) Kurz, Mallotus philippensis (Lam.) Muell.-Arg, Macaranga peltata (Roxb.) Muell.-Arg., Olea dioica Roxb., Sapindus trifoliata L., Strobilanthus sps., Symplocos cochinensis subsp. laurina (Retz.) Nooteb., Symplocos racemosa Roxb., Terminalia paniculata Roth, Vateria indica L., etc. along with the native species. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

AMBIGUITIES IN THE STUDY 9

Rapid assessments of the impact of natural disasters on the flora is usually carried out over one year so it will cover the plants of all growing seasons and also it gives an initial picture on the effects of the community dynamics. The duration of the study was short, and hence it could not assess the status of seasonal plants. Long-term observations are required for solid data on the recovery of native 91 flora on the slide affected areas and the spread of invasive species. Since prevalent fire events and wildlife conflicts were reported from several parts with in the study area during the study period, the team couldn’t survey some high risk areas where there is a possibility of landslides. AMBIGUITIES IN THE STUDY

92 IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

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CONTRIBUTORS & ACKNOWLEDGEMENTS 11

The present study is carried out with financial assistance under the Kerala State Biodiversity Board Plan Schemes 2018–19—Documentation of Specialized Ecosystem and Developing Sustainable Models of Biodiversity Conservation. We are thankful to the Principal Chief Conservator of Forest, Kerala Forest Department for granting us necessary permission for visiting forest areas of Kerala. We are grateful to Ms R. Keerthi IFS and Mr P. Ranjithkumar, Divisional Forest Officers, Wayanad North and South Forest Divisions respectively and Mr N. T. Sajan IFS., Deputy Conservator of Forests & Assistant Wildlife Warden, Wayanad Wildlife Sanctuary for their support. We also place on record the services and co-operation of all the Range Officers of Wayanad North and South Forest Divisions and assistance of forest officers and the tribal watchers, during field surveys. We acknowledge the Wayanad District Soil Conservation Officer for providing details on the landslides occurred in the district outside the forest boundaries, and the Assistant Director of Soil Survey, Wayanad for information on the soil types and its condition after the flood. Thanks, 97 are also due to the Director, Meteorological Centre, India Meteorological Department, Thiruvananthapuram for providing the rainfall details of the study area. Many individuals and their institutions offered their time and experience both formal and informal ways. In this regard, we acknowledge Dr K. M. Prabhukumar, Senior Scientist, Centre for Medicinal Plants Research (CMPR), Arya Vaidya Sala, Kottakkal, Dr A. R. Viji, Assistant Professor, Iqbal College, Thiruvananthapuram, Dr V. Mini, Thiruvananthapuram, Mr Vinod, GIS Analyst, Thiruvananthapuram, Mr Ajayan, District Co-ordinator, KSBB, Wayanad, BMCs and LSGs. We are thankful to Dr Shalini Dhyani, South Asia Regional Chair, IUCN Commission on Ecosystem Management for her constant support and encouragement. ENVIRONMENTAL IMPACT

98 IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

PLATES 12 PLATES

Plate 1. Angiosperm species suffered population loss

Aeschynanthus perrottetii A. DC. Acacia caesia (L.) Willd. Artocarpus heterophyllus Lam.

100

Artocarpus hirsutus Lam. Bischofia javanica Blume Briedelia stipularis (L.) Blume

Canscora diffusa (Vahl) R.Br. ex Roem. & Schult. Caryota urens L. Chionanthus mala-elengi (Dennst.) P.S. Green

Cinnamomum sulphuratum Nees Cipadessa baccifera (Roth) Miq. Clausena anisata (Willd.) Hook.f. ex Benth. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Plate 2. Angiosperm species suffered population loss

Clematis gouriana Roxb. ex DC. Clerodendrum infortunatum L. Clerodendrum philippinum Schauer

101

Colebrookea oppositifolia Smith Debregeasia longifolia (Burm.f.) Wedd. Diplocyclos palmatus (L.) Jeffrey

Elaeocarpus munronii (Wight) Mast. Elaeocarpus tuberculatus Roxb. Elaeocarpus variabilis Zmarzty

Erythrina stricta Roxb. Erythropalum scandens Blume Euphorbia rothiana Spreng. PLATES

Plate 3. Angiosperm species suffered population loss

Exacum carinatum Roxb. Exacum tetragonum Roxb. Ficus exasperata Vahl

102

Ficus racemosa L. Flemingia strobilifera (L.) R.Br. ex Ait.f. Glycosmis pentaphylla (Retz.) DC.

Grevillea robusta Cunn. Helicteres isora L. Holigarna arnottiana Hook. f.

Homonoia riparia Lour. Humboldtia brunonis Wall. Leea asiatica (L.) Ridsd. IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Plate 4. Angiosperm species suffered population loss

Lepianthes umbellata (L.) Rafin. Mallotus philippensis (Lam.) Muell.-Arg. Mallotus tetracoccuss (Roxb.) Kurz

103

Meliosma simplicifolia (Roxb.) Walp. Mesua thwaitesii Planch. & Triana Olea dioica Roxb.

Osbeckia aspera (L.) Blume Pandanus canaranus Warb. Persea macrantha (Nees) Kosterm.

Phoenix loureiroi Kunth Piper nigrum L. Pittosporum tetraspermum Wight & Arn. PLATES

Plate 5. Angiosperm species suffered population loss

Passiflora foetida L. Quassia indica (Gaertn.) Nooteb. Schefflera venulosa (Wight & Arn.) Harms

104

Solanum torvum Sw. Solanum virginianum L. Strobilanthes lupilinus Nees

Syzygium jambos (L.) Alston Thottea siliquosa (Lam.) Ding Hou Thunbergia fragrans Roxb.

Thunbergia mysorensis (Wight) Anders. Vernonia arborea Buch.-Ham. Xanthophyllum arnottianum Wight IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

Plate 6. Pteridophyte species suffered population loss

Adiantum concinnum Humb. & Bonpl. ex Willd. Adiantum latifolium Lam. Angiopteris helferiana C. Presl

105

Anisocampium cumingianum C. Presl Asplenium cheilosorum Kunze. ex Mett. Lygodium flexuosum (L.) Sw.

Lygodium microphyllum (Cav.) R. Br. Osmunda huegeliana C. Presl Pteris confusa T. G. Walker

Pteris heteromorpha Fee Selaginella radicata (Hook. & Grev.) Spring Selaginella tenera (Hook. & Grev.) Spring PLATES

Plate 7. Invasive species found in landslide affected areas

Acalypha indica L. Bidens biternata (Lour.) Merr. & Sheriff Chromolaena odorata (L.) King & H.Rob.

106

Cyperus iria L. Euphorbia hirta L. Ipomoea hederifolia L.

Lantana camara L. Mikania micrantha Kunth Pennisetum polystachyon (L.) Schult.

Stachytarpheta cayennensis (Rich) Schaeur Stachytarpheta jamaicensis (L.) Vahl Pteridium revolutum (Blume) Nakai IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

INDEX 13

Andikunnu, 34, 77 Field Sampling, 12 Angiosperm, 10, 50–59, 61, 62, 85 Fissures, 87 ArcGIS, 13 Floods, 2–4, 10, 77, 78 Arikkallammottamchal, 47, 81 Floristic data, 21 Average monthly rainfall, 20 Forest fire, 86 Biodiversity, 1, 2, 12, 79, 86 Frequency, 1–4, 12, 87 Bioengineering, 88, 89 Geo-textiles, 89 Brahmagiri, 44, 81 Habit class, 59 Chaliyar, 8 Hazard class, 26 107 Changing Climate, 3 Hazard Zonation Map, 26, 27 Charnockite group, 8 High-risk zones, 26, 86 Choice of Species, 89 Hydrological mechanisms, 88 Climate, 3, 8 Impact on livelihood, 77 Cloud Cloud Direction, 85 India Meteorological Department, 15 Comprehensive economic assessment, 83 Integrated technique, 88 Conservation status, 59, 61, 62 Interventions, 87 Contour wattling, 89 Introduction, 1 Coorg plateau, 7 Invasive species, 74, 75, 78, 81, 86, 87 CRED, 83 Issues, 87 Daily rainfall pattern, 16–19 Kambamala, 43, 77, 81, 83 Debris flow, 10, 78 Kerala Scenario, 2 Deccan plateau, 7 KSDMA, 2 DEM, 13, 81 Kurichiyarmala, 49, 77, 83 Density, 12, 13, 81, 85, 90 Kurisukuthi, 41, 77, 81 Direct costs, 83 Lady Smith reserve, 79, 81, 87 Disaster Event, 10 LANDSAT, 81 District Soil Conservation Office, 10, 85 Landslide susceptible zones, 12 Drainage Density Map, 82 Landsliding, 1 Ecological restoration, 89 Long-term modification, 78 Ecosystems, 1, 78, 79, 86, 88 LSGs, 87 Ecotourism, 83 Major landslide affected areas, 22, 23, 77, 85, 87 Endemic species, 63, 64, 66 Major population loss, 65, 68, 85 Environmental Costs, 81 Makkimala—Tirunelli belt, 78 Environmental crisis, 7 Maniyankunnu, 31, 32, 77, 81, 83 ERDAS, 13 Mapping, 5, 12, 26, 78, 85 INDEX

Mechanical mechanisms, 88, 89 Regeneration, 86–88 Medicinal plants, 69–73 Resilient Taxa, 77 Microhabitats, 78, 86 Restoration activities, 85, 88 Migmatite Complex, 8 Restricted distribution, 59 Minor landslide affected areas, 24, 25 Scars, 81, 87 Muthumari, 36, 37, 77, 81, 83 Seismic zone, 2 Natural disaster, 2, 83, 86, 87, 91 Slope movement, 1, 12, 21–25 NbS, 88 Slope stabilization, 89 Nilgiris, 2, 7 Socioeconomic costs, 81 Non-resilient, 87 Soil seed bank, 78, 87 North Division, 8, 10, 85 Sooryamudi, 35, 77, 81 Northeast monsoon, 2, 15 South division, 10, 83, 85 NWFP, 59, 66–68, 85 Southwest monsoon, 2, 8, 15 Objectives, 5 Stream Network Map, 81, 82 Pachotti, 68 Study Site, 7 108 Panamkunduchal, 48, 81 Sugandhagiri, 45–48, 77, 83 Panamkuzhi, 42, 77 Symplocos cochinchinensis, 55, 67, 68, 73, 85 Pancharakolli, 28–30, 32, 77, 83 Symplocos racemosa, 55, 68, 73, 85, 90 Panchayat level analysis, 86 Thacharakolli, 38, 77, 81 Peedikapullu, 45, 46, 81 Thematic layers, 12, 13, 26 Peninsular Gneissic Complex, 8 Tirunelli, 8, 43, 44, 78, 81, 86, 87 Percentage frequency, 12 Top soil loss, 77 Perennial springs, 81 Total monthly rainfall, 20 Phenological changes, 76, 86 Un-sustainable, 87 Physiographic zones, 2, 8 Vateria indica, 51, 62, 64, 65, 67, 73, 85, 90 Phytosociological techniques, 12 Vegetation, 1, 2, 8, 21, 65, 77–79, 86–90 Pollen washout, 86 Vegetative treatments, 88 Population loss, 12, 21, 50–64, 66–68, 70–73, 79, Vulnerable, 2, 3, 26, 61, 62, 86 81, 85, 86 Vythiri mountain belt, 78, 86 Prioritized areas, 87 Wayanad group, 8 Priyadarshini, 39, 40, 77, 81 Wayanad plateau, 8 Pteridophyte, 10, 21, 59, 60, 79, 81, 85, 86 Wildlife Sanctuary, 8, 21 Rainfall percentage departures, 4 Weather hazards, 4 Rainfall, 2–4, 8, 10, 13, 15–21, 76, 85, 88 Western Ghats, 1–3, 7, 8, 10, 59, 63–65, 78, 86 Rainy day, 3 Rassalkunnu, 33 IMPACT OF LANDSLIDES ON THE FOREST ECOSYSTEM IN WAYANAD DISTRICT, KERALA

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