Inventory and Evaluation of Spread Ecology of the Riverine Flora of Achankovil River Basin, Kerala
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Inventory and Evaluation of Spread Ecology of the Riverine Flora of Achankovil River Basin, Kerala Dr. P.M. Radhamany Professor Department of Botany University of Kerala, Karyavattom Thiruvananthapuram Inventory and Evaluation of Spread Ecology of the Riverine Flora of Achankovil River Basin, Kerala 2019 File No. A8/3371/2018/KSBB Thiruvananthapuram Dated 01.12.2018 Team of Experts with Relevant Background Dr. P.M. Radhamany is currently working as Professor at the Department of Botany of University of Kerala, Thiruvananthapuram. She has more than 30 years of research experience in the field of plant taxonomy, phytochemistry and pharmacology, and teaching experience in the post graduate and M.Phil leavel. Dr. Radhamany has handled many research projects from state and central sectors. She has also guided six Ph.D and other eight doctoral students are aiming Ph.D under her mentorship. More than 40 resaerch publications, few book chapters, numerous conference papers are the other credentials of Dr. Radhamany. Besides that, she acts as the member in boards and panels of numerous academic and socio-cultural organizations. Dr. Jose Mathew is Assisatant Professor, Department of Botany, Sanatana Dharma College, Alappuzha and consultant in CNERM, Kochi. He is the recipient of IDEA WILD grant and SERB N-PDF. He introduced 31 new taxa to plant science and made few rediscoveries and new distributional records of plants from Kerala part of Western Ghats. He wrote two scientific books, 30 research articles in scientific journals, 50 articles in popular magazines and presented 20 papers in national and international conferences. Technical Assistance Dr. Valsala Devi (Herbarium Curetor (Retd.), KUBH, University of Kerala) Dr. T.J. Roby Mrs. Remya Krishnan Mr. Sam Alex Miss. Arundhathi Contents Page No. 1.1.1. Introduction 111 1.1. Riparian zones 1 1.2. Significance of riparian zones 1 1.3. Achankovil River 2 1.4. Need and significance of the study 5 1.5. Objectives of the study 7 222.2... RRReviewReview of earlier works 202020 2.1. Flora 20 2.2. Endemic plants 21 2.3. Medicinal and economically important plants 22 2.4. Invasive plants 23 333.3. Methodology 252525 3.1. Categorization of the River Bed 25 3.2. Methods employed for investigation of flora 25 3.3. Assessment of Conservation status 26 3.4. Surveying and mapping 26 3.5. Vegetation studies 27 3.6. Assessment of the flood impact 28 4.4.4. Results and Discussion 22292999 4.1. Species composition 29 4.1.1. Floristic analysis 29 4.1.1.1. Angiosperms 29 4.1.1.2. Non flowering plants 32 4.2. Rare and endemic species 56 4.3. Weed invasion in the study area 74 4.4. Effect of flood in biodiversity 88 4.5. Recommendations 92 References 94 Riverine Flora of Achankovil River Basin 1.1.1. INTRODUCTION Riparian Ecosystem The word riparian is related to living in, or located on the bank of natural water coarse usually a river, sometime a lake or tide water. A riparian zone or riparian area is the interface between the land and the river. Plant communities along the river margins are called riparian vegetation. In a tropical riparian ecosystem, the species composition is an assemblage of evergreen, deciduous, shola and riverine components. 1.1. Riparian Zones 1. CMZ: Chanel Migration Zone (Flowing Zone). True hydrophytes can be seen here. Free floating, rooted free floating, submerged floating, rooted submerged and rooted emergent hydrophytes can be seen here. Woody debris and living vegetation provides shelter, feeding and spawning habitats for birds, fishes and invertebrates. 2. Core zone: Transition zone in between the water and land ecosystem. The vegetation can have both mesophytic and hydrophytic adaptations. Herbs and grasses are the dominant vegetation. Vegetation of this zone provides organic matter to the stream. This filter stream reduces the water temperature. 3. Inner zone: Herbs, shurbs and trees were found here and their roots act as a binding system for the soil and by doing so reduces bank collapse and erosion. 4. Outer zone: Flood plain. This stream side plants play a vital role for river health. Here plants perform a filtering function and prevent sediments and nutrients from entering the stream. Vegetation and leaf litter slow overland water runoff, thus helping to prevent erosion. 1.2. Significance of Riparian Zones Diversity and distribution of riparian plants influence the morphology and hydrological characters of the rivers and its aquatic functions by way off: • Acting as vegetative filter strips to filter the non-point source pollution. • Prevents soil erosion • Promote sediment deposition • Stabilize the stream banks • Manage floods 1 Riverine Flora of Achankovil River Basin • Maintaining water quality parameters • Provides habitats for wildlife and aquatic life form Studies on riverine ecosystem deserve special significance to explore much more hidden potential with multidisplenary relevance on sustainable development comprising climatology, agricultural and fishery management, aquatic bio resources, watershed and energy management, pesticide runoff, eutrophication and population ecology. 1.3. Achankovil River The Achankovil River drains the southern part of the Achankovil Forest Division. The Kallar River on the other hand drains the northern part of the tract finally joins the Achankovil River at Mukkada. The converged and swelled up Achankovil River continues its westward flow through the territory of Konni forests. The Kallar River is the main tributary of Achankovil River This name is derived from the rocky character of its bed. It effectively drains the Kallar valley, through a net work of rills and rivulets. Numerous streamlets and rills flowing down from the western slope of the main ridge between Aruvithalamottai and Uranimottai, join together to form the Mangala Aar. During its westward course, many more brooks such as Vazhaperiyar, Manjapparathodu, Kooramalathodu and Naadukanithodu converge and the watercourse swells up and Kallar River begins to emerge. The Kanayar River that originates from the northern ridges flows in a southerly direction and converges with Kallar River at Kanayarmoozhi. The Chittar River originating from the ridges near Kadamankunnu, drains the northwestern part of the valley, flows in a southerly direction, and converges with Kallar River at Pulikayam. Thenparathodu, Arambathodu and Muthuvanthodu that drain the northwestern part of the tract also join this River at the western boundary, making it a perennial watercourse of this tract. At Mukkada, on the western boundary, this River merges with Achankovil River. Achankovil RiverRiver:: Its total length is 138 kms. Having an extend of 1340.400 sq.kms, the water shed area of this River spreads over 50 villages in Kollam, Pathanamthitta, and Alappuzha Districts. Its average annual sediment load is 77130 ton. The River emanates by the convergences of several streamlets flowing down from the slopes of Pasukkidaimettu, a ridge near Kottavasal (Elevation 700 m above MSL) on the western slope of the main ghats. During its westward course 2 Riverine Flora of Achankovil River Basin many more brooks from the northern side (Kumbavuruttythodu, Kalluruttythodu, Aruvikkarathodu, Kumbalamparathodu, Karadipparathodu) as well as the southern side of the valley (Pallikondan Aar, Muthalathodu, Chittarthodu etc) join the River. At Mukkada, it joins with Kallar River and continues its journey in the westwards to join finally with Pamba River at Veeyapuram. The river thereafter flows northward and falls into Vembanad lake. 1.3.1. Topography of the basin: Like all the river basins in Kerala, the Achankovil basins also can be divided into three natural zones based on elevation, consisting of low land or sea-board, midland and high land. The coast for a short distance along the borders of lakes is flat, retreating from it the surface roughens up into slopes which gradually combine and swell into mountains on the east. The low land area along sea coast is generally swampy and liable to be flooded during monsoon inundation. The plains/midlands succeed low land in gentle ascents and valleys interspersed with isolated low hills. The high land on the eastern portion is broken by long spurs, dense forests, extensive ravines and tangled jungles. Towering above all their slopes are Western Ghats that form eastern boundary of the basins. 1.3.2. Geology of the basin: As per the Geological Survey of India publication No. 30 the most prominent rock formation at the Achankovil site is of Archaean age Charnockites. The major rock types of this tract are Magmatitic Gneissic, Charnockite and Khondalite of Archaean complex. Quartz, Garnet, Hornblende, Feldspars and Black Mica are also found as constituents in these formations. These rocks have suffered intensive deformation like faulting and folding during the different phases of orogeny, most probably due to tectonic disturbances. The general foliation trend shows NW ‐ SE direction, with steep dip towards SW. The heavy rainfall and high temperature, causing alternate cycles of wetting and drying phenomena favour the process of laterization. The major soil types met with in this tract are Red loamy soil, Laterite soil, Alluvial soil, Sandy loam and Clayey soil. 1.3.3. Climate of the ripariane zone: Generally, the climate in this area is moderately hot and humid. The low ‐lying area enjoys a healthy and fairly moderate climate, with not much appreciable variation in either seasonal or diurnal temperatures. However, the interior areas experience a little more climatic variations. The three distinct seasons noted in this tract are cold, hot and wet seasons. The hottest season is noted during February to May and the coldest from December to 3 Riverine Flora of Achankovil River Basin January. In the upland area the temperature declines towards elevated regions. Variations in the radiant energy of the sun with respect to seasons, cloudiness, altitudes, latitudes and diurnal changes were also noted. The temperature varies from 20° C to 36° C in the lower stretches and 17°C to 30 °C at higher altitudes.