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Plant biodiversity Plant biodiversity is that part of nature which includes the differences in genes among the individuals of a species, the variety and richness of all the plant species at different scales in space, locally, in a region, in the country and the world, and various types of ecosystems, both terrestrial and aquatic, within a defined area. It has been estimated that more than 50 million species of plants, animals and micro-organisms are existing in the world. Out of these, about 1.4 million species have been identified so far. Each species is adapted to live in specific environment, from mountain peaks to the depth of seas, from polar ice caps to tropical rain forests and deserts. Plants are multicellular and mostly photosynthetic organisms which found essentially everywhere, both in water and on land. The aquatic plants include red, brown and green algae and the land plants include mosses, ferns, gymnosperms and angiosperms. The angiosperms or flowering plants are dominated the earth the last 70 million years. There are over 3, 00,000 angiosperm species growing on the earth which show enormous diversity in size and form. In India there are about 45,000 plant species are known that represent about 7% of the world’s flora. Nearly, 4900 species of angiosperms are endemic to India. Types of Biodiversity: 1) Species diversity 2) Genetic diversity 3) Ecological diversity
1. Species Diversity: Species is a basic unit of classification and is defined as a group of similar organisms that interbreed with one another and produce offspring’s and share a common lineage. Species diversity refers to biodiversity at the most basic level and is the ‘variety and abundance of different types of individuals of a species in a given area’. It includes all the species on Earth, ranging from plants such as bacteria, viruses, fungi, algae, bryophytes, pteridophytes, gymnosperms, angiosperms and all the species of animals including unicellular protozoans to mammals. Regions that are rich in nutrients and have well balanced climatic factors, such as moderate temperature, proper light and adequate rainfall, show high degree of diversity in their life forms. The tropical areas support more diverse plant and animal communities than the desert and polar areas, as for examples, tropical forest has a higher species diversity as compared to a timber plantation. The regions that are rich in species diversity are called hotspots of biodiversity.
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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2. Genetic Diversity: Genetic diversity pertains to the range of diversity in the genetic resources of the organisms. Every individual member of a plant or animal species differs from other individuals in its genetic constitution. Each individual has specific characters, which is due to the genetic makeup or code. The genes present in the organisms can form infinite number of combinations that causes genetic variability. Thus, we find that each human, who is representative of the same species, i.e. Homo sapiens, is distinct from another. Similarly, there are many varieties within the same species such as rice, wheat, apples, mangoes, etc. that differ from one another in shape, size, colour of flowers and taste of fruits and seeds due to the variations at the genetic level. The term ‘gene pool’ has been used to indicate the genetic diversity in the different species. This also includes the diversity in the wild species, which through intermixing in nature over millions of years have given rise to newer varieties. The domesticated varieties of agricultural crops and animals have also evolved from the wild gene pool. The genetic variability is essential for healthy breeding population, the reduction in genetic variability among breeding individuals leads to inbreeding which in turns can lead to extinction of species. 3. Ecological/Ecosystem Diversity: Each ecosystem consists of organisms from many different species, living together in a region connected by the flow of energy and nutrients. The Sun is the ultimate source of energy for all the ecosystems. The Sun’s radiant energy is converted to chemical energy by plants. This energy flows through the different systems when animals eat the plants and then are eaten, in turn, by other animals. Fungi and bacteria derive energy from the decomposing dead organisms, releasing nutrients back into the soil as they do so. An ecosystem, therefore, is a collection of living components, like microbes, plants, animals, fungi, etc. and non-living components, like climate, matter and energy that are connected by energy flow. Ecological diversity refers to the ‘variability among the species of plants and animals living together and connected by flow of energy and cycling of nutrients in different ecosystems or ecological complexes. It also includes variability within the same species and variability among the different species of plants, animals and microorganisms of an ecosystem. Thus, it pertains to the richness of flora, fauna and microorganisms with in an ecosystem or biotic community. The richness of the biosphere in terms of varied life forms is due to the variations in the ecosystems. The earth has a number of ecosystems like grasslands, forests, semi-arid deserts, marine, freshwater, wetland, swamp, marshlands etc. each one having its distinct floral, faunal and microbial assemblages. Ecological diversity represents an intricate
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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network of different species present in local ecosystems and the dynamic interaction among them. The ecological diversity is of great significance that has developed and evolved over millions of years through interactions among the various species within an ecosystem. Measuring Biodiversity: There are various mathematical ways of measuring biodiversity, which calculate the number of species diversity in different regions. The measure of diversity of species is also known as species richness. These are as follows: a) Alpha diversity: This is the diversity in species, i.e. the number of species within a community. This depends on the interaction between the biotic and abiotic factors and also takes into account immigration from other locations. b) Beta diversity: This is the change in the composition of the species with reference to the changes in the environment. c) Gamma diversity: This refers to the overall diversity and is applied to larger areas in which both alpha and beta diversity are measured. Value of Biodiversity: Biodiversity is the most precious gift of nature the mankind is blessed with. The uniqueness of our planet Earth is due to the presence of life manifested through the diversity in flora and fauna. As all the organisms in an ecosystem are interlinked and interdependent, the value of biodiversity in the life of all the organisms including humans is enormous. Besides its ecological and environmental value, biodiversity has significant socio-economic values as well. • Environmental Value: The diverse group of organisms found in a particular environment together with the physical and biological factors that affect them, constitute an ecosystem. Healthy ecosystems are vital to life. The natural environment is responsible for the production of oxygen, maintenance of water-cycle and other biogeochemical cycles. The more a region is rich in terms of biodiversity, the better are the different cycles regulated. For example, forests regulate the amount of carbon dioxide in the air by releasing oxygen as a by-product during photosynthesis, and control rainfall and soil erosion. As you are well aware, deforestation would further increase carbon dioxide in the earth’s atmosphere leading to greenhouse effect and global warming. This will cause irreparable damage to all organisms including mankind. Ecosystems depend on the health and vitality of the individual organisms that compose them. As all the organisms in an ecosystem
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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are interdependent, removing just one species can prevent the ecosystem from operating normally. • Consumptive Value: This is related to natural products that are used directly for food, fodder, timber, fuel wood, etc. Humans use at least 40,000 species of plants and animals on a daily basis. Many people around the world still depend on wild species for most of their needs like food, shelter and clothing (Fig. 19.4 and Table 19.1). The tribal people are completely dependent on the forests for their daily needs. Similarly, fishermen in the coastal areas are dependent on the marine resources. The wood derived from the forests has been used from the birth of civilization as fuel. • Productive Use Value: This is assigned to products that are commercially harvested and marketed. Almost all the present-day agricultural crops have originated from wild varieties. The biotechnologists continuously use the wild species of plants for developing new, better yielding and disease resistant varieties. Most of the drugs and medicines used in the present times are extracted from different plant parts. • Social Value: The lifestyle of the ancient people was closely interwoven with their surroundings. The life of the indigenous people in many parts of the world still revolves around the forests and environment, even in the modem times. Many of them still live in the forests and meet their daily requirements from their surroundings. In ancient times, especially in India, the environment in totality i.e. flora, fauna, etc. were held in high esteem. Trees like Peepal, Banyan and Tulsi are still worshipped. Ladies offering water to Tulsi daily is considered good and there are festivals when ladies tie sacred threads around Peepal and Banyan trees and pray for the welfare of their families. • Ethical and Moral Values: It is based on the principle of ‘live and let others live’. Morality and ethics teach us to preserve all forms of life and not to harm any organism unnecessarily. Some people take pleasure in the hunting of animals. People also sometimes degrade and pollute the environment by their unethical actions. Through proper education and awareness, the people’s conscience against such practices must be raised. We may not be deriving direct benefits from many plants. Each species has its own utility in the world of biodiversity and has every right to live. • Aesthetic Value: The beauty of our planet is because of biodiversity, which otherwise would have resembled other barren planets dotted around the universe. Biological diversity adds to the quality of life and provides some of the
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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most beautiful aspects of our existence. Biodiversity is responsible for the beauty of a landscape. Humans are also attracted towards the biologically rich regions and nobody likes to live or visit a barren place. People go too far off places to enjoy the natural surroundings and wildlife. This type of tourism is referred to as eco-tourism, which has now become a major source of income in many countries. Eco-tourism includes visiting wildlife sanctuaries, national parks, coral reefs, exotic islands, safaris and trekking in the mountainous and forested areas. In some countries like Nepal, Bhutan, Kenya, Rwanda, eco-tourism has now become the major source of foreign currency income. For example, in India, the richness of flora and fauna are depicted in many paintings; animals are represented as vehicles of Gods; the dances and festivals are intricately associated with nature. Soil conservation Soil is a thin layer of the Earth’s crust formed by mineral particles, organic matter, water, air and living organisms. Soil conservation method is a set of management strategies for prevention of soil being eroded from the Earth’s surface or becoming chemically altered by overuse, acidification, salinization or other chemical soil contamination. Soil conservation is the prevention of loss of the top most layer of the soil from erosion or prevention of reduced fertility caused by over usage, acidification, salinization or other chemical soil contamination. Some soils are rich in organic and humus contents and are more productive while others are less productive and have very poor percentage of organic contents.
The chief agents of soil erosion are water and wind. The actual art of soil conservation is based on certain basic principles which include; Protection of soil from impact of rain drops; To slow down the water from concentrating and moving down the slope in a narrow path; To slow down the water movement when it flows along the slope; To encourage more water to enter into the soil; Reduction in the wind velocity near the ground by growing vegetation cover, ridging the land etc.; The various methods for soil conservation may be broadly arranged into the Biological methods and Mechanical methods A. Biological methods: Biological conservation method is various ways of maintaining a cover of vegetation during the periods of high erosion risk. Biological method is an effective method of soil conservation. Several types of biological soil conservation methods exist those are: • Contour farming • Crop rotation • Strip cropping • Choice of crops • Mulching • Cover crop • Reforestation • mixed crop
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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Contour Farming: Contour farming is the farming practice of planting across a slope following it elevation contour lines. Farming on the contour creates small ridges that slow runoff water, and it increases the rate of water infiltration, reduces the hazard of erosion. Crop Rotation: The change type of plant grown on particular piece of land from year to year or season to season has been found effective for reducing soil loss. Strip Cropping: Strip cropping is a method of farming used when a slope is too steep or too long. Strip cropping helps keep the soil in a long enlarge of land. the strip crops check the surface runoff and force them to infiltrate into the soil, thereby facilitates to the conservation of rain water. Choice of crops: Choice of crop is select the erosion resisting crops and cultivate. Row crops or large growing crops such as sorghum, maize, pearl millet is not protective in conserving soil. Whereas close growing crops such as cowpea, groundnut, green gram, black gram etc., Those crops are soil erosion resisting crops. Then they very effective in reducing soil loss. Mulching: Mulching is a temporary erosion control practice in which materials such as grass, hay, wood chips, wood fibres, straw, or gravel are placed on exposed or recently planted soil surfaces. Vertical mulching also reduces soil loss and increasing infiltration. Cover cropping: A cover crop is a crop of a specific plant that is grown primarily for the benefit of the soil rather than the crop yield. Cover crops are commonly used to suppress weeds, manage soil erosion, help build and improve soil fertility and quality, control diseases and pests, and promote biodiversity. Reforestation: Reforestation involves the replanting or regeneration of areas of forest which have previously been damaged or destroyed. Forest mainly control the splash erosion. for the reason that plant canopy decreases raindrop velocity. Mixed crop: Mixed cropping is the cultivation of more than one type on a piece of land at the same time. E.g. Corn and sugar beet. Here different kind of plants need different level nutrition. Hence soil nutrition isn’t severe losses. Then harvest periods are different. Because different kind of plants. Always cropping cover the surface. So soil erosion can control with mixed cropping.
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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B. Mechanical methods The mechanical practices of soil conservation include various engineering techniques and structures which are adopted to supplement the biological methods when the latter alone are not sufficiently effective. Basin leaching: In this method, a number of small basins (water reservoirs) are made along the contour by means of an implement called basin blister. Basins collect and retain rain water for long period and also catch and stabilize downwardly moving soils of the slopes. Sub-soiling: In this method hard subsoil is broken deeply by mechanical means. This process promotes absorption of rain water in the soil and makes the soil looser and more fit to allow luxuriant growth of vegetation. Contour terracing: Sometimes soil mounds are formed along the contour (at right angles to the slope) to retain water in the soil and check the soil erosion. These are called terraces. Terraces are levelled areas constructed at right angles to the slope to reduce soil erosion. Contour Trenching: This method involves making a series of deep pits (2′ x 1′) or trenches across the slope at convenient distance. The soil excavated from the trenches is deposited along the lower edge in the form of bund. On the ridges tree seeds are sown. Ponds and reservoirs: Small ponds and water reservoirs or dams should also be made at suitable places for irrigation and some other purposes. Various types of dams have been devised to arrest and plug gullies and thus to check soil erosion Social Forestry Social forestry may be defined as additional aid to wildlife conservation. Social forestry is a new revolutionary concept, a multipurpose programme and a mission which aims at ensuring ecological, economic and social security to the people particularly to the rural masses especially by involving the beneficiary’s right from the planting stage to the harvesting stage.
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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It aims at a mixed production of fire wood, timbers, fibres, fruits, fodder and other raw materials for self-consumption and cottage industry. These objectives are achieved through public participation and cooperation. In view of increasing population and deforestation, social forestry will not only serve to meet the ever-increasing demand of fire wood, fodder, timber and a variety of tree-based produce for rural cottage industries but also to maintain the ecological balance. The term social forestry was first used in 1976 by The National Commission on Agriculture, when the government of India aimed to reduce pressure on forests by planting trees on all unused and fallow lands. Social forestry schemes can be categorized into groups: farm forestry, community forestry, extension forestry and agroforestry. • Farm forestry: In Farm forestry or agroforestry, trees are grown on farmland for commercial and non-commercial purposes. Farmers are encouraged to plant trees on their own farmland to meet their domestic needs. Farmers often grow trees to provide shade for agricultural crops, as wind shelters, for soil conservation or to recover wasteland. • Community forestry: The government provides seedlings and fertilizer to the community, which is then responsible for nurturing and protecting the plants on community land. This provides for the community rather than individuals. • Extension forestry: Planting of trees on the sides of roads, canals and railways, along with planting on wastelands is known as extension forestry, increasing the boundaries of forests. This has created wood lots in the village common lands, government wastelands, and panchayat lands. • Agroforestry: In agroforestry, silvicultural practices are combined with agricultural crops like legumes, along with orchard farming and livestock ranching on the same piece of land. It is defined as a sustainable land-use system that maintains or increases the total yield by combining food crop together with forest tree and livestock ranching on the same unit of land, using management practices that consider the social and cultural characteristics of the local people and the economic and ecological condition of the area. Uses of social forestry ➢ It makes available much needed fuel wood, fodder and other useful plant products to the farmers for their personal use. ➢ It increases the income of the farmers. ➢ Tree plantation near agricultural fields provides safety to crops from the adverse effects of strong wind, cold waves and heat waves. ➢ It helps in the maintenance of fertility and productivity of soil. ➢ The money earn by the farmers through social forestry enables them to repay the debts or loans in short period of time.
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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Hotspots A biodiversity hotspot is a biogeographic region with significant levels of biodiversity that is threatened by human habitation. To qualify as a biodiversity hotspot on Myers 2000 edition of the hotspot-map, a region must meet two strict criteria: it must contain at least 0.5% or 1,500 species of vascular plants as endemics, and it has to have lost at least 70% of its primary vegetation. Around the world, 36 areas qualify under this definition. These hotspots support nearly 60% of the world's plant, bird, mammal, reptile, and amphibian species, with a very high share of those species as endemics. Some of these hotspots support up to 15,000 endemic plant species and some have lost up to 95% of their natural habitat. Hotspots of Biodiversity in India Of the twenty-five hotspots of biodiversity, recognized in the world, two are found in India, which extend into the neighbouring countries. The Indo- Burma region covering the Eastern Himalayas and the Western Ghats – Sri Lankan region. The botanical hotspots of India include: a. Western Ghats b. Indo-Burma c. The Himalayas and d. Andaman and Nicobar Islands a) Western Ghats: The Western Ghats run parallel to the west coast of India and constitute more than 16,000 km strip of forests in the states of Maharashtra, Goa, Karnataka, Tamil Nadu and Kerala. Locally they are also known as the Sahyadris. The Western Ghats by virtue of having a humid tropical climate and geological stability supports one of the most biodiversity rich areas of the country. According to an estimate, of the 17,000 flowering plants species reported from India, more than 4,500 occur in the Western Ghats region. The dominating plant families are Acanthaceae, Graminae, Orchidaceae, Rubiaceae, Labiatae, Compositeae and Leguminoseae. More than 200 species of rare orchids, many of them are endemic, are found in Western Ghats. Many economically important plants such as banana, rice, black pepper, ginger, etc. have spread to other parts of the country from here. b) Indo-Burma: Knowledge of plant species within the Indo-Burma hotspot is uneven and is hampered by socio-political divisions and taxonomic complications. A conservative estimate of total plant diversity in the hotspot reveals about 13,500 vascular plant species, of which about 7,000 (52%) are endemic. Among the flora of the Indo-Burma Hotspot are a wide array of orchid and ginger species (there are more than 1,000 orchid
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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species in Thailand alone) and many tropical hardwood trees, including commercially valuable dipterocarp species and teak (Tectona grandis). c) The Himalayas: The Himalaya Hotspot is home to the world's highest mountains, including Mt. Everest. The mountains rise abruptly, resulting in a diversity of ecosystems that range from alluvial grasslands and subtropical broadleaf forests to alpine meadows above the tree line. Of the estimated 10,000 species of plants in the Himalaya hotspot, about 3,160 are endemic, as are 71 genera. Furthermore, five plant families are endemic to the region, the Tetracentraceae, Hamamelidaceae, Circaesteraceae, Butomaceae and Stachyuraceae. The largest family of flowering plants in the hotspot is the Orchidacea, with 750 species, and a large number of orchids, many representing rather young endemic species. d) Andaman and Nicobar island It is one of the biologically richest hotspots on Earth, holding about 25,000 species of vascular plants, 15,000 (60%) of which are found nowhere else. One plant family, the Scyphostegiaceae, is confined to the hotspot and is represented by a single tree species, Scyphostegia borneensis. There are about 3,000 species, including more than 265 species of dipterocarps; no less than 155 of these are endemic to the island. Notable plants in the hotspot include members of the genus Rafflesia, represented by 16 species with very large flowers. One of these, Rafflesia arnoldii, has the largest flowers in the world, measuring up to one meter in diameter. Endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and invasive species. The flora of India is one of the richest in the world due to the country's wide range of climate, topology, and environment. There are over 15,000 species of flowering plants in India which account for 6% of all plant species in the world. Many plant species are being destroyed, however, due to their prevalent removal. Roughly 1/4 of all plant species in the world are at risk of being endangered or going extinct. The combination of global warming and habitat destruction is the sole reason for the disappearance of many plants. Some of the endangered plant species are ▪ Assam Catkin Yew (Amentotaxus assamica)- Arunachal Pradesh: These are coniferous trees which are found only in Arunachal Pradesh. There have been records of low rates of reproduction from this tree and thus are an endangered the plant species in India. ▪ Ilex Khasiana- Shillong Meghalaya: Found in the upper hills of Shillong, Meghalaya, these are very rare and endangered.
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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▪ Red Sandalwood (Pterocarpus Santalinus)- Eastern Ghats: This is a very rare form of sandalwood found in southeastern India. The red sandalwood is very well-known for its medicinal properties. It is especially useful for treating skin problems and giving a natural sheen, glow, and fairness to the skin. ▪ Ebony (Diospyros Celibica)- Karnataka: Well-known for its dark, durable and high-quality wood, ebony is a much popular tree found in Karnataka, India. It is highly sought-after for furniture and woodwork. However, due to the indiscriminate cutting and deforestation in the region, the density of these trees has remarkably depleted. ▪ Musli (Chlorophytum Tuberosum)- Tamil Nadu: Musli is a flowering plant found merely in the interiors of Africa and South India. It is a well- known Ayurvedic medicine which gives vitality and strength. However, due to indiscriminate harvesting, there is a notable depletion in the quantity of this plants. ▪ Actinodaphne Lawsoni- Kerala: This is a canopy or sub-canopy tree which is found in the in Kerala. It is popular for its medicinal properties and thus due to extensive harvesting, is endangered. ▪ Malabar Mahagony (Kingiodendron Pinnatum)- Kerala, Karnataka, Tamil Nadu: Another tree which is known for its wood; Malabar Mahogany is on its way of depletion. The durable wood is widely used in furniture and due to its wide demand, there has been a huge number of trees cutting. Also, the destruction of habitat has led to low reproduction in these trees. Red data book The Red Data Book is a public document which is created for recording endangered and rare species of plants, animals, fungi as well as some local subspecies which are present in a particular region. The Red Data Book helps us in providing complete information for research, studies and also for monitoring the programs on rare and endangered species and their habits.This book is mainly created to identify and protect those species which are on the verge of extinction. The International Union for Conservation of Nature maintains the Red Data Book. IUCN is the world’s most detailed inventory centre of the global conservation status of biological species. The International Union for Conservation of Nature (IUCN) was founded in 1964 with an aim to maintain a complete record of every species that ever lived. The Red Data Book contains colour-coded information sheets, which are arranged according to the extinction risk of many species and subspecies. ▪ Black represents species which are confirmed to be extinct. ▪ Red represents species that are endangered ▪ Amber for those species whose status is considered to be vulnerable
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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▪ White is assigned for species that are rare ▪ Green for species that were formerly endangered, but their numbers have started to recover ▪ Grey coloured for the species that are classified as vulnerable, endangered, or rare but sufficient information is not available to be properly classified. Red Data Book indexes species as: Threatened, Not threatened and Unknown. Furthermore, The Red Data Book also has information as to why a species has become extinct along with the population trends and the extent of its range (distribution). Advantages of the Red Data Book ✓ It helps in identifying all animals, birds and other species about their conservation status. ✓ It is used to evaluate the population of a particular species. ✓ The data available in this book can be used to evaluate the taxa at the global level. ✓ With the help of this book, we can estimate the risk of taxa becoming globally extinct. ✓ Provides a framework or guidelines for implementing protective measures for endangered species. Vulnerable or Threatened species: A vulnerable species is one which has been categorized by the International Union for Conservation of Nature as likely to become endangered unless the circumstances that are threatening its survival and reproduction improve. Vulnerability is mainly caused by habitat loss or destruction of the species home. Eg: Diospyros celibica (Ebony tree)threatened species in Karnataka Rare: A Taxon is considered to be Rare when a Taxon live in small population localized with in restricted geographical area. Human activities do not endanger or threat it but they are at risk. A rare species is a group of organisms that are very uncommon, scarce, or infrequently encountered. Eg: Psilotum nudum rare to Karnataka. Phytogeographical regions of India The Indian sub-continent is characterised with a variety of climate types and the flora of the country is also correspondingly of different types in its different types. The country has been into the following nine floristic regions for the study of flora: India has been divided into the following botanical zones by D. Chatterjee (1962).
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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1) Western Himalayas, 2) Eastern Himalayas, 3) Indus plain, 4) Gangetic plain, 5) Central India, 6) Deccan 7) Western coasts of Malabar, 8) Assam, and 9) Bay Islands of Andaman and Nicobar. 1. Western Himalayas: It extends from Kumaon to Kashmir and has annual rainfall up to 200 cm. Altitudinally there are following three zones of vegetation corresponding to three climatic belts: a. Sub-montane zone: This extends upto 1500 metres altitude and comprises mostly of Siwalik ranges. The forests are tropical and sub-tropical having trees such as Shorea robusta, Dalbergia sissoo, Cedrela toona, Ficus glomerata, Eugenia jambolano, Acacia catechu, Butea monosperma, Zizyphus and thorny succulent euphorbias on slopes. b. Temperate zone: Above submontane zone extend montane temperate forests up to 3500 metres altitude. They are dominated by plant species such as Quercus, Acer, Uinnus, Rhododendron, Betula (birch), Salix (cane), Populus, Cormis, Prumus, Fraximus, Pimus, Cedrus, Picea and Taxus. c. Alpine zone: This zone extends from 3500 to 4500 metres altitudes (snow line) and is characterised with alpine forest vegetation with scrub and meadows. Most common tree species are Abies, Betula, Jniperus and Rhododendrons. The herbs which occur near the snow line include species such as Primula, Potentilla, Polygomm, Geranium, Saxifrago, Aster, etc. 2. Eastern Himalayas: Eastern Himalayas extend from Sikkim to upper Assam and Darjeeling. Vegetation of this region differs from that of western Himalayas. The chief differences are due to changed environmental factors as heavy monsoon rainfall, less snowfall and high temperature and humidity. This region can also be divided into: a. Tropical or Submontane Zone: The tropical subzone characterized by warm and humid conditions extends from plain up to the altitude of about 1800 m. In this zone mostly sal forests,
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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and mixed deciduous forests consisting of important plants, such as Sterculia, Terminalia, Anthocephalus cadamba and Bauhinia are common. b. Temperate or Montane Zone: It may be further divided into upper and lower zones Lower temperate zone is the region between 1800 and 3000 metre altitudes. In the lower temperate zone, Oaks (Quercus). Michelia, Pyrus, Cedrela, Eugenia, Echinocarpus are common plants. c. Alpine Zone (from 4000 metres up to snow line): Climate is humid and extremely cold. The vegetation in the alpine zone is characterised by complete absence of trees and predominance of shrubs and meadows. Important plants of this zone are Rhododendron and Juniperus. 3. Indus Plains: It includes part of Punjab, Rajasthan, Cutch, Delhi, a part of Gujarat. Some part of this plain is now in Pakistan. The climate of this zone is characterised by dry hot summer, and dry cold winter. Rainfall is usually less than 70 cms. Vegetation is mainly bushy and thorny Acacia arabica, Prosopis spicigera, Salvadora Capparis, Calotropis, Dalbergia sisso, Albizzia lebbek, Zizyphus nummularia are very common plants of this region. 4. Gangetic Plains: This is one of the richest vegetational zones in India. This zone covers flat land of a part of Delhi, whole of U.P., Bihar, and West Bengal and also a part of Orissa. Rainfall in this zone is from 50 cm to 150 cm. Plants such as Dalbergia sisso, Acacia arabica, Terminalia tomentosa, T. belerica, Bauhinia, Diospiro, Madhuca indica, Tamarindus, Mango (Mangifera indica). Ficus sps is common. 5. Central India: Central India covers Madhya Pradesh, part of Orissa (now Odisha), Gujarat and Vindhya. The areas are hilly. The average rainfall per annum may be 100-170 cm. Biotic disturbances are very common in this botanical province which have led to the development of the thorny vegetation in open areas. In this region teak (Tectona grandis) and sal (Shorea robusta) forests are very common. Other trees are Terminalia tomentosa, Bauhinia, Mango, Phyllanthus, Ficus glomerata, etc. Among common shrubs are Mimosa rubricaulis, Desmodium, Acacia sp., Zizyphus rotundifolia. 6. Deccan: This region comprises whole of the southern peninsular India including Satpura and southern part of Godawari River. Average annual rainfall in this region is about 100 cm. In Deccan plateau teak forests containing Diospiros, Acacia, Prosopis spicigera, Santalum album (Chandana), Capparis, Euphorbias, Phyllunthus, Tectona grandis, Pterocarpus, Borassus, Foenix silvestris. 7. Western Coast of Malabar: This is small botanical province covering Cape Comorin to Gujarat and Western Ghats .This is a region of heavy rainfall. In tropical evergreen forest the trees are tall and they have root buttresses. Important species are Cedrela toona Dipterocarpus.
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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Mangifera indica, Sterculia alata, Artocarpus hirsuta. In the mixed deciduous forests, important plants are Terminalia tomentosa, Terminalia peniculata Tectona grandis, Dalbergia, Lagerstroemia lanceolata and bamboo species. 8. Assam: This botanical province is very rich in vegetation and covers valley of Brahmaputra, Naga hills and Manipur. This is the region of heaviest rainfall. Cherapunji is one of the rainiest place in the world where annual rainfall often exceeds 1000 cm. Common plants occurring in this region are Ficus, Artocarpus, Michelia champaca, Sterculia alata. Morus species. Besides these bamboos canes, climbers, and green bushes are also common. Prominent plants in the northern forests of this zone are Alnus nepalensis, Betula. Rhododendron arboreum. Magnolia, Michelia and Prunus. 9. Bay Islands of Andaman and Nicobar (India):Islands: These are represented by the Andaman and Nicobar islands in the east and Lakshadweep islands in the west. The Andaman and Nicobar Islands are a group of more than 300 islands. These bay islands represent elevated portions of submarine mountains. Climate is humid in the coastal region. In Andaman, beech forests, evergreen forests, semi- evergreen forests deciduous forests and mangrove vegetation are of common occurrence. Rhizophora Mimusops, Calophyllum, etc. are common plants in mangrove vegetation. In the interior evergreen forests tall trees are common. Important species of trees are Calophyllum, Dipterocarpus, Lagerstroermia and Terminalia. Vegetational types of Karnataka Karnataka is one such state where it has magnificent forests in the India. From the evergreen forests of Western Ghats to scrub or thorny forests in plain areas. 1) Evergreen and Semi-evergreen: An evergreen forest is a forest consisting entirely or mainly of evergreen trees that retain green foliage all year round and Semi-evergreen forests are generally considered as a transitional stage between evergreen and moist deciduous forests.These forests are characterised by ever-green trees mixed with deciduous having typical features like less dense canopy, grew gariousness, frequent buttressed trunks, thicker and rougher barks, and heavy climbers. Ex: Dipterocarpus indicus, Hopea parivflora, Myristíca fauna, Gymnacranthera canarica, Vateria indica etc.
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur
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2) Moist Deciduous: Temperate deciduous forests are located in the areas that has moderate rainfall and temperature and with cold winters. These are the typical monsoon forests in areas where the amount of annual rainfall ranges between 100 cm and 150 cm with mean annual temperature of 24°C to 27°C, and humidity percentage of 60 to 80 They mostly occur along the eastern slopes of the Western Ghats, north- eastern part of the Peninsula. teak (Tectona gradis) are commercially the most significant species; occupying the relatively wetter north- eastern parts of the Peninsula. Ex: Terminalia, Largerstroemia, preterocarpus, Xylia, Tectona and Anogeissus etc. 3) Dry Deciduous Forest: The tropical deciduous forests shed leaves during December (in NorthernHemisphere) as water becomes scarce. This type is a degraded version of the moist deciduous. It occupies a vast area of the country between moist deciduous (in the east) and tropical thorn (in the west) forests. Ex: Acacias, Hardwikicia, Neem, Pongamia, Somida, Santalam albam, Ficus ete., 4) Scrub and Thorny Forest: These forests are confined to areas where the rainfall is very low. Here due to scarcity of rainfall the trees are stunted. Eg: Acacia species, Balanites rorburghii, Cordia myxa, Capparis spp, Prosopis spp, Azadirachta indica, Cassia fistula, Diospyros chloroxylon, Carissa carandas and Phoenix sylvestris etc 5) Un-wooded: These forests are mainly grass lands and waste land.
Dr Ashwathanarayana R, Guest faculty, Dept of Botany, SSCASCW, Tumkur