Biodiversity or biological diversity is a term given to the variety of life on the earth and natural patterns it forms.
Biodiversity or biological diversity is a term given to the variety of life on the earth and natural patterns it forms. Biodiversity is also defined as the variability among living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species and of ecosystems (defined in UN Earth summit 1992).
Biodiversity includes all the different plants, animals and microorganisms, the genes they contain and the ecosystems of which they form a part. Biodiversity maintains ecological balance and continuous evolutionary processes. It also includes genetic differences within each species. The building blocks of life i.e., the chromosomes, genes and DNA, determine the uniqueness of each individual and each species. The United Nations designated 2011- 2020 as the united Nations decade on biodiversity.
There are three levels of biodiversity:
1. Genetic diversity:- All the different genes contained in all the living species is called Genetic diversity. It is concerned with variation in genes within a particular species. Genetic diversity allow species adapt to changing environment. This diversity aims to ensure that some species survive drastic changes and thus carry on desirable genes.
2. Species diversity: It is all the different species, as well as the differences within and between different species. It is the ratio of one species population over total number of organisms across all the species in the given biome. Zero represents infinite diversity and one represent only one species present.
3. Ecosystem diversity: This refers to all the different habitats, biological communities and ecological processes, as well as variation with an individual ecosystems. There are several kinds of habitats around the world. Changing climatic conditions is accompanied by changing Habitat as well. This leads to species adapting itself to the changed environment. The species which best adapts becomes predominant. Thus the variety or diversity of species is influenced by the nature of the ecosystem.
Measurement of biodiversity
Diversity is a single statistic in which the number of species richness and evenness are compounded.
Diversity is measured by two major components:
1. Species richness: It is the number of different species represented in a set or collection of individuals. Species richness is simply a count of species and does not include the abundance of the species. Species richness and species evenness is included in species diversity.
2. Species evenness: It is the measure of the proportion of species at a given site.
Distribution of biodiversity:
The current distribution of plants and animals reflects a long evolutionary response to the changing climate and configuration of oceans and continents. Biomes are defined by the plants and animals adapted to the environmental conditions found there. The geography of world biomes is highly dependent on climate. Recent climate change has made changes in the distribution of plants and animals.
Biodiversity is not evenly distributed, it varies greatly across the globe as well as within the regions. Diversity of all living things depends on temperature, precipitation, altitude, soils, geography and the presence of other species. The tropics have more biodiversity compared to the poles. This is referred as latitudinal gradient in species diversity. Several ecological mechanism contribute to the gradient, but the ultimate factor behind many of them is the greater mean temperature at the equator compared to that of the poles.
The two most species rich habitats are the rainforests and the coral reefs located in tropical regions. Through extinction some species are lost and new species arise through the process of speciation. Since the rates of extinction and speciation are not constant over time, species richness varies considerably through evolutionary time.
Importance of biodiversity:-
Biodiversity is extremely important people and to the health of the ecosystem. Biodiversity helps in protection of water resources, soils formation and protection, nutrient storage and recycling, pollution breakdown and absorption, contribution to climate stability, maintenance of ecosystems and recovery from unpredictable events.
For humans it provides food, medicinal resources and Pharmaceutical drugs, wood products, ornamental plants, breeding stocks, population reservoirs, future resources and diversity in genes, species and ecosystems. It also helps in Research and Education apart from having recreation and tourism aspects.
Threats to biodiversity: Loss of biodiversity occurs when either a particular species is destroyed or the habitat essential for its survival is damaged. This loss of biodiversity is called as extinction. The extinction of species can take place due to natural causes or due to man made causes. Extinction may also occur due to environmental reasons like ecological substitutions, biological factors and pathological causes which can be caused either By nature or man.
Natural causes include floods, earthquakes, landslides, rivalry among species and lack of pollination and diseases. Man made causes include habitat destruction, uncontrolled commercial exploitation, hunting and poaching, introduction of alien species, conversion of rich biodiversity site for human settlement in industrial development, extension of agriculture or homer harvesting, pollution, filling up of wetlands and destruction of coastal areas.
Conservation of biological diversity leads to the reservation of Genetic diversity of plants and animals, sustainable utilisation of life support Systems on earth and assures sustainable utilisation of potential resources.
Modes of conservation:
There are two types of modes of conservation: Ex situ conservation and in situ conservation. Ex situ conservation implies conserving biodiversity outside the areas were the naturally occur. Zoological Parks or botanical gardens, seed banks Botanical, horticulture, and recreational Gardens are important centres for ex situ conservation.
In situ conservation implies conserving the animals and plants in their natural habitats. National parks sanctuaries, biosphere Reserves, reserved forests, protected forests and nature reserves are important centres for in situ conservation.
A biogeographic region with a significant reservoir of biodiversity that is under threat from humans is known as a biodiversity hotspot. Norman Myers was the first man to speak of the concept of biodiversity Hotspots. At present there are 35 biodiversity hotspots around the world. To qualify as a hotspot a region must have the following to strict criteria: 1) species endemism - contain at least 1500 species of vascular plants as endemics and 2) degree of threat - it has to have lost at least 70% of its original habitat.
The hottest Hotspots:
Some hot spots are much richer than others in terms of their endemics. The following factors are taken into consideration to determine the hottest Hotspots.
1) endemic plants
2) endemic vertebrates
3) endemic plants per area ratio
4) endemic vertebrates per area ratio
5) remaining primary vegetation as percentage of original extent.
There are 8 hottest Hotspots at present. They are Madagascar, Philippines, Sundaland, Brazil's Atlantic forest, Caribbean, Indo - Burma, western Ghats/ Sri Lanka and eastern arc and coastal forests of Tanzania/ Kenya.
Indian Biodiversity Hottest Hotspots
1) The Western Ghats and Sri Lanka: The Western Ghats are a chain of hills that run along the western edge of peninsular India. Their proximity to the ocean and through orographic effect, they receive high rainfall. These regions have moist deciduous forest and rain forest. The region shows high species diversity as well as high levels of endemism. Nearly 77% of the amphibians and 62% of the reptile species found here are found nowhere else. Sri Lanka, which lies to the south of India, is also a country rich in species diversity. It has been connected with India through several past glaciation events by a land bridge almost 140kn wide. The highest concentration of species in the Western Ghats is believed to be the Agasthyamalai Hills in the extreme south. The important populations include Asian Elephant, Nilgiri Tahr, Indian Tigers, Lion tailed macaque, Gaint squirrel etc.
2) The Eastern Himalayas: The Eastern Himalayas is the region encompassing Bhutan, northeastern India, and southern, central, and eastern Nepal. The region is geologically young and shows high altitudinal variation. Together, the Himalayan mountain system is the world's highest, and home to the world's highest peaks, which include Mount Everest and K2. The Eastern Himalayan hotspot has nearly 163 globally threatened species including the One-horned Rhinoceros (Rhinoceros unicornis), the Wild Asian Water buffalo (Bubalus bubalis (Arnee)) and in all 45 mammals, 50 birds, 17 reptiles, 12 amphibians, 3 invertebrate and 36 plant species The Relict Dragonfly (Epiophlebia laidlawi) is an endangered species found here with the only other species in the genus being found in Japan. The region is also home to the Himalayan Newt (Tylototriton verrucosus), the only salamander species found within Indian limits. The Himalayas are home to over 300 species of mammals, a dozen of which are endemic. Mammals like the Golden langur, The Himalayan tahr, the pygmy hog, Langurs, Asiatic wild dogs, sloth bears, Gaurs, Muntjac, Sambar, Snow leopard, Black bear, Blue sheep, Takin, the Gangetic dolphin, wild water buffalo, swamp deer call the Himalayan ranged their home. The only endemic genus in the hotspot is the Namadapha flying squirrel which is critically endangered and is described only from a single specimen from Namdapha National Park.
3) Indo-Burma: The Indo-Burma region encompasses several countries. It is spread out from Eastern Bangladesh to Malaysia and includes North-Eastern India south of Brahmaputra river, Myanmar, the southern part of China's Yunnan province, Lao People’s Democratic Republic, Cambodia, Vietnam and Thailand. The Indo-Burma region is spread over 2 million sq. km of tropical Asia. Since this hotspot is spread over such a large area and across several major landforms, there is a wide diversity of climate and habitat patterns in this region. Much of this region is still a wilderness, but has been deteriorating rapidly in the past few decades. In recent times, six species of large mammals have been discovered here: Large-antlered muntjac, Annamite muntjac, Grey-shanked douc, Annamite striped rabbit, Leaf deer, and the Saola. This region is home to several primate species such as monkeys , langurs and gibbons with populations numbering only in the hundreds. Many of the species, especially some freshwater turtle species, are endemic. Almost 1,300 bird species exist in this region including the threatened white-eared night-heron, the grey-crowned crocias, and the orange-necked partridge. It is estimated that there are about 13,500 plant species in this hotspot, with over half of them endemic. Ginger, for example, is native to this region.
Man and the Biosphere Programme: Launched in 1971, UNESCO’s Man and the Biosphere Programme (MAB) is an Intergovernmental Scientific Programme that aims to establish a scientific basis for the improvement of relationships between people and their environments.
MAB combines the natural and social sciences, economics and education to improve human livelihoods and the equitable sharing of benefits, and to safeguard natural and managed ecosystems, thus promoting innovative approaches to economic development that are socially and culturally appropriate, and environmentally sustainable.
It predicts the consequences of today’s actions on tomorrow’s world and thereby increases people’s ability to efficiently manage natural resources for the well-being of both human populations and the environment. Its World Network of Biosphere Reserves currently counts 669 sites in 120 countries all over the world, including 20 transboundary sites.
By focusing on sites internationally recognized within the World Network of Biosphere Reserves, the MAB Programme strives to:
• Identify and assess the changes in the biosphere resulting from human and natural activities and the effects of these changes on humans and the environment, in particular in the context of climate change.
• Study and compare the dynamic interrelationships between natural/near-natural ecosystems and socio-economic processes, in particular in the context of accelerated loss of biological and cultural diversity with unexpected consequences that impact the ability of ecosystems to continue to provide services critical for human well-being.
• Ensure basic human welfare and a liveable environment in the context of rapid urbanization and energy consumption as drivers of environmental change.
• Promote the exchange and transfer of knowledge on environmental problems and solutions, and to foster environmental education for sustainable development.
Biosphere reservesBiosphere reserves are sites established by countries and recognized under UNESCO's Man and the Biosphere (MAB) Programme to promote sustainable development based on local community efforts and sound science.The programme of Biosphere Reserve was initiated by UNESCO in 1971. The purpose of the formation of the biosphere reserve is to conserve in situ all forms of life, along with its support system, in its totality, so that it could serve as a referral system for monitoring and evaluating changes in natural ecosystems.
BRs are special environments for both people and the nature and are living examples of how human beings and nature co-exist while respecting each others needs. Each reserve promotes solutions reconciling the conservation of biodiversity with its sustainable use. Biosphere reserves are ‘Science for Sustainability support sites’ – special places for testing interdisciplinary approaches to understanding and managing changes and interactions between social and ecological systems, including conflict prevention and management of biodiversity.
Biosphere reserves are nominated by national governments and remain under the sovereign jurisdiction of the states where they are located. Their status is internationally recognized.The first biosphere reserve of the world was established in 1979, since then the network of biosphere reserves has increased to 669 in 120 countries across the world, including 20 transboundary sites.
The main characteristics of biosphere reserves are:
• Achieving the three interconnected functions: conservation, development and logistic support;
• Outpacing traditional confined conservation zones, through appropriate zoning schemes combining core protected areas with zones where sustainable development is fostered by local dwellers and enterprises with often highly innovative and participative governance systems;
• Focusing on a multi-stakeholder approach with particular emphasis on the involvement of local communities in management;
• Fostering dialogue for conflict resolution of natural resource use;
• Integrating cultural and biological diversity, especially the role of traditional knowledge in ecosystem management;
• Demonstrating sound sustainable development practices and policies based on research and monitoring;
• Acting as sites of excellence for education and training;
• Participating in the World Network.