UjjwalWeb: Biodiversity : Significance, Threat & Conservation

Biodiversity

Definition

'Biological diversity' means the variability among living organisms from all sources including, inter alia, 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. The variety of life at every hierarchical level and spatial scale of biological organizations: genes within populations, populations within species, species within communities, communities within landscapes, landscapes within biomes, and biomes within the biosphere.

Global Biodiversity Gradient

Biodiversity is not distributed evenly across the planet: Biodiversity is not distributed evenly across the planet but shows a rather uneven distribution, certain ecosystems and regions contain far more species than others. Tropical rain forests, coral reefs, the deep sea, and large tropical lakes appear to be the most species rich ecosystems on the planet (WCMC 1992; Heywood 1995; Levin 2001). For most groups of terrestrial plants and animals, species diversity is lowest near the poles and increases toward the tropics, reaching its peak in tropical rain forests. These forests, occupying only 6 percent of the earth’s land surface, are believed to contain more than half the species on earth.

Biodiversity in Indian context

India has only 2.4 per cent of the world’s land area, its share of the global species diversity is an impressive 8.1 per cent. That is what makes our country one of the 12 mega diversity countries of the world. Nearly 45,000 species of plants and twice as many of animals have been recorded from India. How many living species are actually there waiting to be discovered and named? If we accept May’s global estimates, only 22 per cent of the total species have been recorded so far. Applying this proportion to India’s diversity figures, we estimate that there are probably more than 1,00,000 plant species and more than 3,00, 000 animal species yet to be discovered and described. Would we ever be able to complete the inventory of the biological wealth of our country? Consider the immense trained manpower (taxonomists) and the time required to complete the job. The situation appears more hopeless when we realise that a large fraction of these species faces the threat of becoming extinct even before we discover them. Nature’s biological library is burning even before we catalogued the titles of all the books stocked there.

Biodiversity in the international context

Biodiversity is defined as the “variability among living organisms from all sources, including, inter alia, terrestrial, marine, and other aquatic ecosystems, and the ecological complexes of which they are part: this includes diversity within species, between species and of ecosystems” (CBD, 1992). The three ultimate objectives of the 1992 UN Convention on Biological Diversity (CBD) are:

the conservation of biological diversity;
the sustainable use of its components;
the fair and equitable sharing of the benefits arising out of the utilization of genetic resources.

In 2002, parties to the CBD adopted a strategic plan “to achieve by 2010 a significant reduction of the current rate of biodiversity loss at the global, regional and national level as a contribution to poverty alleviation and to the benefit of all life on Earth” (the 2010 target; Decision VI/26). This target was subsequently endorsed by the World Summit on Sustainable Development and incorporated as a target under the Millennium Development Goals. It is widely acknowledged however, that the 2010 biodiversity target was not met. Recognising the importance of this global environment problem, the United Nations General Assembly declared 2011-20 the United Nations Decade on Biodiversity. The tenth meeting of the Conference of Parties (COP-10) to the CBD in 2010, held in Nagoya, Japan, led to the successful agreement on a revised Strategic Plan for Biodiversity 2011-2020 and the Aichi Biodiversity Targets. In addition, Parties adopted a Strategy for Resource Mobilisation, a consolidated list of guidance to the financial mechanism, and an international regime for Access and Benefits Sharing (i.e. for the equitable sharing of the benefits arising out of the utilisation of genetic resources). CBD COP-11 in October 2012, in Hyderabad, India focused on addressing implementation issues and established, for example, an indicator framework to monitor progress on the implementation of the Aichi Biodiversity Targets and the Strategy for Resource Mobilisation. The OECD’s analysis supports the work of the CBD.

Evolution of Biodiversity

Biodiversity is a product of the numerous biological and geophysical events that have occurred over the history of life on Earth.

Life on Earth is 3.7 - 3.85x109 years old
Evolutionary history shapes contemporary physical and biological environment
Current diversity of species is a product of the processes of extinction and speciation

Extinction

Extinction is an important part of the process of evolution of biodiversity and does not occur at a constant pace. It is the complete disappearance of a species from Earth. Thus, extinction is the final and irreversible event of species loss. In contrast, extirpation is the local or regional disappearance of a species from only a part of its range. There have been at least five periods when there was a sudden increase in the rate of extinction – to at least double – affecting many different types of plants and animals.

Levels of biodiversity

Biodiversity is commonly considered at three different levels:

Within species (intraspecific) diversity; usually measured in terms of genetic differences between individuals or populations.
Species (interspecific) diversity, measured as a combination of number and evenness of abundance of species.
Community or ecosystem diversity, measured as the number of different species assemblages.

Biodiversity, therefore, is usually considered at three hierarchical levels i.e. Genetic, Species and Community and Ecosystem levels.

1. Genetic diversity

Genetic diversity refers to any variation in the nucleotides, genes, chromosomes, or whole genomes of organisms. This is the “fundamental currency of diversity” (Williams and Humphries, 1996) and the basis for all other organismal diversity. Genetic diversity is the sum total of genetic information, contained in the genes of individuals of plants, animals and microorganisms that inhabit the earth. It is needed by any species in order to maintain reproductive vitality, resistance to disease and the ability to adapt to changing conditions. It enables a population to adapt to its environment and to respond to natural selection. The amount of genetic variation is the basis of speciation. Genetic diversity within a species often increases with environmental variability. Such genetic variability has made it possible to produce new breed of crops plants and domestic animals, and in the world allowed species to adapt to changing conditions.

2. Species diversity:

A group of organisms genetically so similar, that they can interbreed and produce fertile off springs is called a species.
The species diversity is usually measured in terms of the total number of species within discrete geographical boundaries.
Species diversity - “species are groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups” (Mayr 1963)
Species are distinct units of diversity each playing a specific role in the ecosystem.
In nature, both the number and kind of species, as well as the number of individuals per species vary, leading to greater diversity. The different sample areas showing species richness (sample area 1), Species evenness (sample area 2) and diversity due to taxonomically unrelated species (sample area 3).

3. Community-level diversity:

It is defined by the species that occupy a particular locality and the interactions between them. It represents the collective response of species to different environmental conditions. Biological communities such as deserts, grasslands, wetlands, and forest support the continuity of proper ecosystem functioning by providing ecological beneficial services to people.

Diversity at the level of community and ecosystem exists along 3 levels.

It could be within-community diversity (alpha diversity), between-communities diversity (beta diversity) or
diversity of the habitats over the total landscape or geographical area (gamma diversity).

Alpha, Beta, and Gamma Diversity

Whittaker (1972) described three terms for measuring biodiversity over spatial scales: alpha, beta, and gamma diversity.

Alpha Diversity : refers to the diversity within a particular area or ecosystem, and is usually expressed by the number of species (i.e., species richness) in that ecosystem.
Beta diversity : a comparison of diversity between ecosystems, usually measured as the amount of species change between the ecosystems.
Gamma diversity : a measure of the overall diversity within a large region.

The values of biological diversity

Human society depend on biological diversity for almost all the food supply, half of its medicines, much of its clothing and in some region virtually all of its fuel and building material and as well as, of course, an important part of its mental and spiritual welfare.
Ecological services Biological diversity as a resource. The three main approaches used for determining the value of biological resources.
Consumptive use value: The biological resources are consumed directly, without passing to the market. Assessing the value of nature’s products - such as fire wood, fodder, game meat, etc.
Productive use value: The resource comes through market or trading. Assessing the value of products that are commercially harvested, such as timber, fish, game meat sold in a market, ivory, and medicinal plants.
Non-consumptive use value: The resources meant for the future potential uses of biodiversity (tourism, scientific research) and ecological balance.

Benefits of biodiversity

1. Economical benefits –

Food value – providing food to the human population on this earth for thousands of years. In the process of development of human civilization, man has unfolded many plant and animal life forms which are directly or indirectly helpful for him in solving his food problem. Due to the scientific advancement many new taxa have been discovered which are high yielding.
Commercial value –timber which is a major component of material used for providing shelter to man. Natural fibres like cotton and silk are still used for clothing by human population.
Medicinal value –Medicines, drugs and pharmaceuticals. Many plant genetic resources are used from derivation of basic drugs. These plant resources vary from actinomycetes and fungi to large trees. Traditional knowledge of indigenous people still keeps an edge over the scientific knowledge in this field. This benefit of biodiversity is still unexplored as the scientists could assess a small fraction of biodiversity for their potential for medicine and agriculture.
Aesthetic value – Man has always been fascinated by the natural beauty and nature has inspired him resulting in development of his moral and ethical values. This intrinsic value of plants and animals are independent of their economic and commercial value. Wonderful plants and animals of this planet not only reflect their aesthetic value but they can make us think of the creator. This opens doors for spiritually which envisages to live in harmony with the nature.

2. Ecological benefits/services (Indirect use value) – Biodiversity supplies the buffering capacity and stability to life on the planet by maintaining the interactive dynamics of the ecosystems of the world.

Causes of biodiversity loss

The Millennium Ecosystem Assessment identifies habitat change, climate change, invasive species, over-exploitation and pollution as the primary drivers leading to loss of biodiversity.

Habitat change : Humans have had an effect on every habitat on Earth, particularly due to the conversion of land for agriculture. Cultivated systems (areas where at least 30% of the landscape is in croplands, shifting cultivation, confined livestock production, or freshwater aquaculture) now cover one quarter of Earth’s terrestrial surface. Habitat loss also occurs in coastal and marine systems, though these changes are less well documented. Trawling of the seabed, for instance, can significantly reduce the diversity of benthic habitats.
Climate change : Observed recent changes in climate, especially warmer regional temperatures, have already had significant impacts on biodiversity and ecosystems, including causing changes in species distributions, population sizes, the timing of reproduction or migration events, and an increase in the frequency of pest and disease outbreaks. By the end of the twenty-first century, climate change and its impacts are likely to be the dominant direct driver of biodiversity loss and changes in ecosystem services globally.
Invasive Species : The spread of invasive alien species has increased because of increased trade and travel. While increasingly there are measures to control some of the pathways of invasive species, for example, through quarantine measures and new rules on the disposal of ballast water in shipping, several pathways are not adequately regulated, particularly with regard to introductions into freshwater systems.
Over-exploitation : For marine systems, the dominant direct driver of change globally has been over fishing. Demand for fish as food for people and as feed for aquaculture production is increasing, resulting in increased risk of major, long-lasting collapses of regional marine fisheries. 50% of the world’s commercial marine fisheries are fully exploited whilst 25% are being over exploited. For example, the Atlantic cod stocks off the east coast of Newfoundland collapsed in 1992, forcing the closure of the fishery, the depleted stocks may not recover even if harvesting is significantly reduced or eliminated.
Pollution (especially nutrient loading) : Since 1950, human mediated increases in nitrogen, phosphorus, sulphur, and other nutrients (nutrient loading) has emerged as one of the most important drivers of ecosystem change in terrestrial, freshwater, and coastal ecosystems, and this driver is projected to increase substantially in the future. For example, humans now produce more biologically available nitrogen than is produced by all natural pathways combined. Aerial deposition of reactive nitrogen into natural terrestrial ecosystems, especially temperate grasslands, shrub-lands, and forests, leads directly to lower plant diversity; excessive levels of reactive nitrogen in water bodies, including rivers and other wetlands, frequently leads to algal blooms and eutrophication in inland waters and coastal areas. Similar problems have resulted from phosphorus, the use of which has tripled between 1960 and 1990. Nutrient loading will become an increasingly severe problem, particularly in developing countries and particularly in East and South Asia.

The World Conservation Union (IUCN) (formerly known as International Union for the Conservation of Nature and Natural Resources, IUCN) has recognized eight Red List categories according to the conservation status of species. These categories are defined below :

The IUCN Threat Categories

Extinct : A taxon is extinct when there is no reasonable doubt that the last individual has died. Extinct in the wild A taxon is extinct in the wild when exhaustive surveys in known and/or expected habitats have failed to record an individual.
Critically endangered : A taxon is critically endangered when it is facing high risk of extinction in the wild in immediate future.
Endangered : A taxon is endangered when it is not critically endangered but is facing a very high risk of extinction in the wild in near future.
Vulnerable : A taxon is vulnerable when it is not critically endangered or endangered but is facing high risk of extinction in the wild in the medium term future.
Lower risk : A taxon is lower risk when it has been evaluated and does not satisfy the criteria for critically endangered, endangered or vulnerable.
Data deficient : A taxon is data deficient when there is inadequate information to make any direct or indirect assessment of its risk of extinction.
Not evaluated : A taxon is not evaluated when it has not yet been assessed against the above criteria.

Examples of species which are categorised by Red list by IUCN (The International Union for conservation of Nature)

Chinese Pangulin : Critically Endangered Species

Scimitar Oryx : Extinct Species

Gaur (Indian Bias) : Vulnerable Species

Great Indian Bustard : Endangered Species

Primates : Least Concerned Species

Nilgiri Tahr : Endangered Species

Few Species categorised as Not Threatened

Status of threatened species

The IUCN Red List is an authentic source of information for this purpose. The 2000 Red List is the latest available. It uses a set of criteria, relevant to all species and all regions of the world, to evaluate the extinction risk of species. The 2000 Red List contains assessment of more than 18,000 species; 11,000 of which are threatened (5,485 animals and 5611 plants). Out of these, 1,939 are listed as critically endangered (925 animals, and 1,014 plants).According to the Red List, in India, 44 plant species are critically endangered.,113 endangered and 87 vulnerable. Amongst animals, 18 are critically endangered, 54 endangered and 143 Vulnerable. A few examples of these plant and animals are given below :

Examples of threatened species in India

Critically endangered : Plant Species - Berberis nilghiriensis, Animal Species - Sus salvanius, (Pigmy hog)
Endangered Plant : Species - Bentinckta nicobarica, Animal Species - Allurus fulgens , (Red Panda)
Vulnerable : Plant Species - Cupressus cashmeriana, Animal Species - Antilope cervicapra, (Black buck)

Biodiversity Conservation

Why Should We Conserve Biodiversity?

There are many reasons, some obvious and others not so obvious, but all equally important. They can be grouped into three categories: narrowly utilitarian, broadly utilitarian, and ethical. The narrowly utilitarian arguments for conserving biodiversity are obvious; humans derive countless direct economic benefits from nature-food (cereals, pulses, fruits), firewood, fibre, construction material, industrial products (tannins, lubricants, dyes, resins, perfumes) and products of medicinal importance. More than 25 per cent of the drugs currently sold in the market worldwide are derived from plants and 25,000 species of plants contribute to the traditional medicines used by native peoples around the world. Nobody knows how many more medicinally useful plants there are in tropical rain forests waiting to be explored. With increasing resources put into ‘bioprospecting’ (exploring molecular, genetic and species-level diversity for products of economic importance), nations endowed with rich biodiversity can expect to reap enormous benefits. The broadly utilitarian argument says that biodiversity plays a major role in many ecosystem services that nature provides. The fast-dwindling Amazon forest is estimated to produce, through photosynthesis, 20 per cent of the total oxygen in the earth’s atmosphere. Can we put an economic value on this service by nature? You can get some idea by finding out how much your neighborhood hospital spends on a cylinder of oxygen. Pollination (without which plants cannot give us fruits or seeds) is another service, ecosystems provide through pollinators layer – bees, bumblebees, birds and bats. What will be the costs of accomplishing pollination without help from natural pollinators? There are other intangible benefits – that we derive from nature–the aesthetic pleasures of walking through thick woods, watching spring flowers in full bloom or waking up to a bulbul’s song in the morning. Can we put a price tag on such things? The ethical argument for conserving biodiversity relates to what we owe to millions of plant, animal and microbe species with whom we share this planet. Philosophically or spiritually, we need to realise that every species has an intrinsic value, even if it may not be of current or any economic value to us. We have a moral duty to care for their well-being and pass on our biological legacy in good order to future generations. How do we conserve Biodiversity? When we conserve and protect the whole ecosystem, its biodiversity at all levels is protected - we save the entire forest to save the tiger. This approach is called in situ (on site) conservation. However, when there are situations where an animal or plant is endangered or threatened and needs urgent measures to save it from extinction, ex situ (off site) conservation is the desirable approach.

In situ conservation – Faced with the conflict between development and conservation, many nations find it unrealistic and economically not feasible to conserve all their biological wealth. Invariably, the number of species waiting to be saved from extinction far exceeds the conservation resources available. On a global basis, this problem has been addressed by eminent conservationists. They identified for maximum protection certain ‘biodiversity hotspots’ regions with very high levels of species richness and high degree of endemism (that is, species confined to that region and not found anywhere else). Initially 25 biodiversity hotspots were identified but subsequently nine more have been added to the list, bringing the total number of biodiversity hotspots in the world to 34. These hotspots are also regions of accelerated habitat loss. Three of these hotspots – Western Ghats and Sri Lanka, Indo-Burma and Himalaya – cover our country’s exceptionally high biodiversity regions.

Although all the biodiversity hotspots put together cover less than 2 percent of the earth’s land area, the number of species they collectively harbour is extremely high and strict protection of these hotspots could reduce the ongoing mass extinctions by almost 30 per cent. In India, ecologically unique and biodiversity-rich regions are legally protected as biosphere reserves, national parks and sanctuaries. India now has 14 biosphere reserves, 90 national parks and 448 wildlife sanctuaries. India has also a history of religious and cultural traditions that emphasised protection of nature. In many cultures, tracts of forest were set aside, and all the trees and wildlife within were venerated and given total protection. Such sacred groves are found in Khasi and Jaintia Hills in Meghalaya, Aravalli Hills of Rajasthan, Western Ghat regions of Karnataka and Maharashtra and the Sarguja, Chanda and Bastar areas of Madhya Pradesh. In Meghalaya, the sacred groves are the last refuges for a large number of rare and threatened plants.

Ex situ Conservation – In this approach, threatened animals and plants are taken out from their natural habitat and placed in special setting where they can be protected and given special care. Zoological parks, botanical gardens and wildlife safari parks serve this purpose. There are many animals that have become extinct in the wild but continue to be maintained in zoological parks. In recent years ex situ conservation has advanced beyond keeping threatened species in enclosures. Now gametes of threatened species can be preserved in viable and fertile condition for long periods using cryopreservation techniques, eggs can be fertilised in vitro, and plants can be propagated using tissue culture methods. Seeds of different genetic strains of commercially important plants can be kept for long periods in seed banks. Biodiversity knows no political boundaries and its conservation is therefore a collective responsibility of all nations. The historic Convention on Biological Diversity (‘The Earth Summit’) held in Rio de Janeiro in 1992, called upon all nations to take appropriate measures for conservation of biodiversity and sustainable utilisation of its benefits. In a follow-up, the World Summit on Sustainable Development held in 2002 in Johannesburg, South Africa, 190 countries pledged their commitment to achieve by 2010, a significant reduction in the current rate of biodiversity loss at global, regional and local levels.

Multilateral Environment Agreement

In response to the current rate of biodiversity loss, and on the grounds that biodiversity is a common concern for humankind, the Convention on Biological Diversity (CBD)was opened for signature in 1992. As of June 2013 it has been ratified by 193 parties (governments). The CBD provides a global legal framework for action on biodiversity and is considered a key instrument for sustainable development. Its three main goals are:

The conservation of biological diversity;
The sustainable use of the components of biological diversity;
The fair and equitable sharing of the benefits arising from the use of genetic resources.

The CBD’s governing body is the Conference of the Parties (COP). It holds periodic meetings to review progress on the Convention targets, and advance its implementation. To support implementation of the CBD, the United Nations General Assembly declared 2011-2020 the United Nations Decade on Biodiversity and adopted the Strategic Plan for Biodiversity 2011-2020. The Strategy is a ten-year framework for action adopted by signatory countries in 2010 in Nagoya, Japan. It builds on the vision that “by 2050, biodiversity is valued, conserved, restored and wisely used, maintaining ecosystem services, sustaining a healthy planet and delivering benefits essential for all people”. The Strategy calls for all countries and stakeholders to effectively implement the three objectives of the CBD by establishing national and regional targets, feeding into the five strategic goals and 20 global targets (collectively known as the Aichi Biodiversity Targets) outlined by the Strategy. The primary framework for action set forth by the CBD is the ecosystem approach, an integrated strategy for the management of biodiversity resources.

Biodiversity is also at the centre of a number of other Conventions e.g. the Convention on Migratory Species (CMS), the International Treaty on Plant Genetic Resources for Food and Agriculture (Plant Treaty), The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). It is also the subject of a number of associated Protocols such as the Specially Protected Areas Protocol and the Cartagena Protocol. A new platform, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), was established by the international community in 2012 and is open to all United Nations member countries. It is an independent intergovernmental body committed to providing scientifically-sound assessments on the state of the planet’s biodiversity in order to support informed decision-making on biodiversity and ecosystem services conservation and use around the world.

Measuring and monitoring biodiversity

Over the last 30 years, many different definitions of biodiversity have been used. As early as 1992, the year the Convention on Biological Diversity was opened for signature at the Rio Earth Summit, it was noted that the definitions of biodiversity are ‘‘as diverse as the biological resource’’. While the CBD definition is commonly accepted, the variety of definitions of biodiversity is particularly relevant when it comes to the scientific measurement of biodiversity. For the purposes of detailed analysis, and the creation of indicators to measure or monitor trends, exactly how biodiversity is defined will influence what is measured. Biodiversity indicators aim at using quantitative data to measure aspects of biodiversity, ecosystem condition, services, and drivers of change. This advances understanding of how biodiversity is changing over time and space, why it is changing, and what the consequences of the changes are for ecosystems, their services, and human well-being. The huge variety of elements included in the definition of biodiversity results in a varied set of methodologies to measure the natural environment. There is no unified metric for quantitative measurement. The variety of metrics employed include : species richness (number of species); population number (number of genetically distinct populations of a particular species defined by analysis of a specific element of its genetic makeup) ; genetic diversity (The variation in the amount of genetic information within and among individuals of a population, a species, an assemblage, or a community ; species evenness (measurement of how evenly individuals are distributed among species) ; and phenotypic (organism characteristics) variance, (the measurement of the different between the phenotypes within a sample).

Biodiversity measurement and policy

The detail of how to measure biodiversity is an area of discussion particularly relevant at the science/policy interface. The CBD-mandated Biodiversity Indicators Partnership (BIP) promotes the development of indicators in support of the CBD and related Conventions, national and regional governments and a range of other sectors. Indicators initiated under the partnership are linked to the goals of the Strategic Plan for Biodiversity 2011-2020 and include habitat extent, protected areas and species extinction.

Recent Transition in Biodiversity Conservation