BIODIVERSITY AND ITS CONSERVATION
By Dr. Ashok Kumar Panigrahi.
The word ‘biodiversity’ is a contraction of the term, ‘natural biological diversity’. Biodiversity refers to the range of variations or differentiations among same set of living entities. The term biodiversity is commonly used to describe the numbers, variety and variability of living organisms at the species level. Actually it is synonym of ‘Life on Earth’. It is estimated that there are about 50 million species of plants, animals and microorganisms with 35 thousand plants having medicinal properties, great bulk of it forming food of one another, species differing in physical & chemical characteristics. Plant diversity: is important to animals, herbivores and man, because, it meets the metabolic necessity of the trophic levels with the nutritional values of its fruits and seeds through dietary phytochemicals, primary and secondary.
Primary phyto chemicals such as carbohydrates, proteins and fats are necessary for energy production in the predators/ grazers/browsers
Secondary phyto chemicals have 2 pronged actions- either as deterrents or as stimulants.
Deterrents- toxic at high dose, prevent over predation/grazing/browsing, a sort of defense chemicals for their very survival;- may be either allomones or keiromones; some seeds may have 3 or more such chemicals in them acting as protease inhibitors as Lecithin, alkaloids, uncommon amino acids, glycosides and polyphenols.
Stimulants- are volatiles, as terpenoids, fatty acid derivatives-those induce pollination.
Microbial diversity is just a subset of biodiversity involving bacteria, fungi, actinomycetes, micro algae, protozoans and other monerans.
A total of 16, 04,000 species of Monera, Protista, Fungi, Plantae and Animalia have been described globally (Whittfield, 2002) though it is likely to be 17,980,000 species i.e. about 11 times more than the presently known species. (Khoshoo, 1995).
India is rich in microbial biodiversity and there are about 850 (0.67%) Moneran species, 2577 (2.04%) Protistan species, 23,000 (18.23%) fungal species, 2500 (2%) species of algae in India, (Khoshoo, 1995). Watve et al (1999) observed a plausible estimate of several fold higher myxobacterial diversity in India than the species recorded worldwide so far. They reported 8 novel myxobacterial types out of 32 species described in Bergey’s Manual of Determinative Bacteriology
Microorganisms occur every where on the planet and more so in the tropics where humidity and temperature are better suited for them to grow and multiply.
Among these organisms, bacteria and fungi are of more importance to man because they are often employed to human advantage, such as Lactobacillus for curd making, yeast for fermenting and Bacillus thuringiensis for pest control and so on. Nitrifying and denitrifying bacteria help regulate nitrogen cycle, who convert aerial nitrogen to ammonia and nitrate and also back convert them to Nitrogen, thus preventing their harmful concentrations through accumulations.
In nature, the microbial populations are never allowed to gain in number naturally, as there are protozoa who feed on them and keep their number under check.
Aesthetic and ethical- man has grown with diversity and love it immensely. People go to the forests or the country sides to watch the nature which give them pleasure.
Through such a nature watch, Hugo de Vries, the father of genetics had discovered mutation in a population of Evening prime rose, Oenothera lamackiana.
In Mexico, there occurred several species of wild perennial corn. Subsequent hybridization produced the perennial cultivated corn. Peru possesses the widest potato diversity even today, the result of Darwin’s Artificial selection
Man needs the diversity, especially plant diversity for various reasons such as deriving medicine from them, as for example, quinine and aspirin. He needs the animal diversity as well, deriving Angiostenin from American pit viper, and Oysters in Chesapeake Bay filter the water
Loss of plant biodiversity will reduce rain fall (1/4rth.), increase global temperature (2-40C) and air pollution alarmingly.
Heritable variation within and between populations of organisms, ultimately depends on the sequence of four base pairs, as component of nucleic acids, constitute the genetic code.
New genetic variation arises by gene and chromosome mutations or by recombinations. Other variations are related to – the amount of DNA per cell, chromosome structure, number and set. Genetic variations influence both natural evolutionary changes and artificial selective breeding.
Patterns in Diversity
Usually 2 following patterns are observed –
(A) Alpha Diversity: It is the number of species in a given area and the patterns of their geographical distribution. It is relatively well documented for a wide variety of organisms and has led tro such generalization as – ‘diversity increases as latitude decreases’.
The species is the smallest and basic unit of life.
Individual name is the stamp of identity and symbol of communication to which most information is attached. Biodiversity is generally viewed as synonym of diversity of species and even the varieties within the species. Species has a direct effect on the community structure. Red data list and species information provide diversity status
Sustainable utilization of species is demarcation of hot & cold spots.
Defining the species
Taxonomic: Smallest group or population that are distinct and distinguishable from one another.
Biological: Group of inter breeding population composed of reproductively isolated populations having local and geographical bases.
Biosystematics: Based on fertility relationship determined by artificial hybridization; this includes ecotypes, eco species, cenospecies etc.
Biosystematics: Based on fertility relationship determined by artificial hybridization; this includes ecotypes, eco species, cenospecies etc.
Evolutionary: Lineage, ancestor to descendent sequence of population existing in space and time.
Species (Systematic) Diversity
Species diversity deals with the variety of living species in different geographical areas, often expressed in terms of species richness or species abundance. Species level is generally considered as the most natural one. Number of species only provides a partial indication of biological diversity. The ecological importance of a species can have a direct effect on community structure and thus overall biodiversity. Species in a true sense represents the unit of living beings.
Numbers of described species of living organisms.
Kingdom and major subdivision
Cellular slime mold
Plasmodial slime mold
Mosses, liverworts, hornworts
(ii) Cnidaria, Ctenophora
(2) Other arthropods
(ix) Minor invertebrate phyla
Jelly fish, Corals, Comb jellies
Nematodes (Round worms)
Annelids ( Earthworms and relatives
Echinoderms (star fish and relatives
lampreys and Hagfishes
Sharks and other cartilaginous fishes
TOTAL: All organisms
Importance of Biodiversity
Direct economic benefits
Tropical rain forest products like Oils, Gums, Rubber, Fiber, Tannin, Dyes, Resins, Turpentine, wide varieties of roots, fruits and ornamental plants.
Indirect ecological benefits
a. Evolutionary change, b. Crop improvement and c. Transgenic Organisms
Geographic varieties have provided the materials for agricultural manipulations of more productive and disease resistant strains
Medicinal Values and Food Security
Biodiversity has value in and of itself and it is inherently wrong to destroy it. [Kormondy, 1996]
Causes of Biodiversity Loss
1. Introduction of unwanted exotic species; for example- Stephen island Wrens were eliminated by the Light House keeper’s cat
2. Habitat destruction; Man – Animal conflict especially in India and loss of tigers and elephants to poachers in almost all National parks in India;
Economical gains- The state of Rondonia in western Amazonia lost 20% of rain forest, the richest source of biodiversity, in 5 years to foreign interests, like soy cultivation and cattle ranching; Surinam and Guyana are on the brink of losing much of their forests for the same reasons.
3. Introduction of GE/GM crops in agriculture; the male sterility factors in these crops render natives go sterile through pollination; Bt. Cotton has caused loss of all native cotton varieties in the cotton belt.
4. Excess human interference owing to population explosion.
The problem of biodiversity is essentially one of conflict resolution between the human kind on one side and living organisms inhabiting different habitats on other side. The UNCED (United Nations Conference on Environment and Development) process has helped place the loss of biodiversity and it’s conservation on global agenda. The Convention on Biological Diversity (CBD) that emerged from the UNCED or Earth Summit at Rio de Janeiro in June 1992 is now a treaty. According to the World Conservation Monitoring Center, 1,604,000 species have been described at the global level. India accounts for 8% of global biodiversity existing in only 2.4% land area of the world (Khoshoo 1996; Varley and Scot 1999). Biodiversity conservation requires certain specialized techniques for applications in reclaiming degraded habitats and employing both ex situ and in situ techniques.
Survey and Maintenance of Biodiversity
Two techniques are followed; 1. Satellite Remote Sensing (S RS) and
2. Geographic Information System (GIS)
According to Burley, the following 4 steps are to be followed:
1. Identification and classification of biodiversity, 2. Location of areas managed primarily for biodiversity, 3. Identification of biodiversity that is un or under represented in those managed areas and 4. Setting principles for conservation actions
5 Steps to be followed for effective conservation
1. The area is to be identified, 2. Population viability analysis is to be made 3. Habitat quality analysis is to be made 4. Introduction of identified/ selected (in situ/ ex situ) species if they are not there and 5. Area maintenance through boundary demarcation with necessary protection is to be made.
Conservation Strategies Followed
(A) In-situ conservation: (B) Ex-situ conservation: (C) Reduction of Anthropogenic pressure: (D) Restoration or rehabilitation of threatened species:
Noss & Cooperider have identified 2 filters for conservation-
1. Coarse filter strategies – deal with conservation of common species and misses species with restricted distribution and 2. Fine filter strategies – deal with the rare natural communities.
The Endangered Species Act of 1973 is a fine filter approach that protects one species at a time, is a powerful tool that can rescue a species from the brink of extinction.
Biodiversity Management Network
Ecosystems and species are represented in areas managed for biodiversity. The species persists because populations else where escape catastrophic events. Hence, it is necessary that in a given geographic range, the species must have multiple representations.
Pressy et al postulate 3 principles –
1. Complementarity – refers to adding species to a given set of areas which are maximally different;
2. Flexibility – refers to the alternative areas to which a particular species can be added
3. Irrepressibility – refers to those elements of biodiversity which will occur only in a certain area and not every where.
Vision or Mission for New Millennium
Conservation of the integrity and diversity of nature, Inheritance of knowledge and biodiversity for future generations, Hot spot areas calling for urgent attention, Biodiversity loss, Fresh water shortage, Climate Change, Sustainability of agriculture
Biotechnology in food productions, Demographics and Consumption , Diminishing resources, Marine and coastal environment
Wild Land Biodiversity
Wild lands are removable, conservable or conserved but in a sense un productive land, like cash in a shoe box, neither earning interest nor circulating, although some concerned people across the nations argue that tropical wild lands are highly productive and are being systematically plundered for mining, agriculture and human settlements.
Environmental necessities demand that these wild lands must be preserved at any cost in order to prolong life in this planet at this juncture because they act as the carbon sinks. Hence, it must escape the tragedy of the commons.
‘Dos’ and ‘Don’ts’ of Wild Land Biodiversity:
1. The more we know about it the more we can use it without damaging.
3. The use of wild land biodiversity must be scheduled and well monitored
4. The use of wild land biodiversity should not be for free and all users must pay for it in some currency.
Use of tropical wild land biodiversity
1. Identification, taxonomy and data base – is necessary to know and record ‘data’ – a. Knowledge of part(s) in use, b. exchange knowledge of use and experience, and c. transfer of knowledge to data center.
2. Micro geography of habitat – knowledge on the location of the species.
3. Collector’s knowledge of sustainable use – directly from those who frequent the wild and from those who keep track of these hunter-gatherers – about location, existence and appropriate collection method(s) of the part(s) of the species.
4. Basic Natural History of the species – to study the life cycle to find out the troubled stages of the species, that will help its conservation.
All information so gathered must be fed to the All Taxa Biodiversity Inventory (ATBI) and UNESCO’s DIVERSITAS to attract global attention and possible help towards conservation of the species in view.
Managing wild land biodiversity
Presently the tropical wild land biodiversity is highly threatened due to several factors such as growing un employment. Much of Amazonia has been lost in recent years for illegal timber, cattle ranch and soy cultivation Owing to climate change and habitat loss 15-20% of endangered species are gone and the rest will follow soon if corrective measures are not taken soon. Such large scale destructions did take place during Cretaceous but then the land was returned back to the biodiversity which can not happen now.
Terrestrial conserved wild lands are habitat islands joined by a few aerially mobile organisms. With increasing intensities of impacts of on-site users, the species may soon be forgotten out side the conserved wild land.
A conserved wild land should not go bankrupt till production starts up again though a conserved wild land can not provide all the necessities of the community until a certain time.
A conserved wild land should not be like a monoculture agroscape of just one species , rather biodiverse in nature.
Role of biodiversity in courtships and breeding; a sample case study, The Bower birds and their Bower building –
The Bower building birds of Australo-Papuan region belong to the family, Ptylorhynchidae, comprising of 6 genera divisible in to 2 groups – 1. The cat birds, monogamous, do not build bower exhibit no courtship. 2. Other 5 genera are all polygynous, males building either typical bowers or nuptial courts with materials derived from biodiversity and displaying courtship to attract females for mating. Of them, 2 genera, Amblyornis and Prionodura known as Mc Gregor’s bower birds are Maypole builders, build maypoles of single or double spires decorating the saplings with sticks and moss in to a cone shaped dome with a base diameter of 25cm. The floor has a moss mat also. The decorative used are from the biodiversity often numbering around 2 thousand. The Avenue building Satin bower birds of Australia, build bowers composed of 2 walls of sticks aligned North–>South having a central avenue. The decorated display court is at the north end. During courtship the male holds a decoration in its beak and release diverse vocalizations. The 2 others, Tooth billed and Archibald bower birds build nuptial courts using large biodiverse objects as decorations placed around several trees.
Nature is the embodiment of biodiversity. Evolutionary processes over the millennia have produced diversity in abundance in all life forms. Thus, microbial biodiversity is quite but natural. Advancements in the field of biotechnology in recent years have empowered scientists to manipulate biodiversity to human advantage and more so in the field of the microbes, though however, it also threatens the very existence of natural biodiversity. Modern genetical tools like recombinant DNA technology, protoplast fusion and hybridoma have exploited the microbes the most, especially since industries started funding such research projects the world over. It began with Anand Mohan Chakravorty developing an altered microbe who could ingest oil spills in the sea and neutralize the same. But the alarming fact is that such inventions are not always for the benefit of the mankind and end up in benefiting the funding – industries at the cost of mankind and the natural biodiversity. For example – Bt. Cotton that failed and the loss of wide natural cotton diversity owing to its introduction. Such transgenic crops invariably carry with them a terminator gene, a male sterility factor that neutralize the diversity.
The factors which govern microbial diversity include – 1. their genetic constitutions with their ability to perform; 2. their micro and macro environment and 3. their ecological interactions with other organisms, both micro and macro.
Micro organisms occur every where in the planet and more diversely in the tropics where temperature and humidity are favourable for them. Their smallness enables them to escape detection unless there is a bloom.
A wide diversity of bacteria are beneficial to man; for example – Lactobacillus in curd making; yeast in fermenting and Bacillus thuringiensis in agricultural pest control etc. There is one, the magneto tactic bacteria which possess intra cellular magnetic particles that allow them to orient to the Earth’s magnetic poles. Many bacteria can be cultured in artificial media yet many others can not be, hence, neither fully known nor studied. Till date about 3 – 4 thousand of them have been studied and about 3 lakh not studied.
Virus do not survive free in nature and barring a few no virus was known to be beneficial to man until biotechnologists found them ideal vectors in synthetic gene transfers from test tubes to the cells of organisms. In the process if any virulent portion of viral gene remains active, there is great danger ahead. Of the 5 thousand or so viruses available only about 5 hundred have been studied.
Under very favourable conditions bacteria attain population blooms. In such conditions methanogenic bacteria produce methane in abundance; carbogenic fungi and bacteria produce CO2 in excess. Both of these are GhGs. Blue-green bacteria produce dimethyl sulphide, a substance that promotes cloud formation and precipitation. In marine environment, cyanobacteria also produce dimethyl sulphide in large quantities. The DMS being volatile is readily oxidized in the atmosphere to-methyl sulphoxide and then to methyl sulphate that acts as the nucleating agent in water droplet formation and cause rain.
The nitrifying and denitrifying bacteria produce nitrates and nitrous oxide respectively. Some nitrate is used up by the green plants but excess of it is leached in to the under ground water tables resulting in nitrate toxicity in those who drink that water. Nitrous oxide destroys the ozone layer increasing U-V penetration and causing skin cancer in human beings.
The soil is enriched by a set of soil bacteria/fungi such as Rhizobium, Azospirillum, Azotobacter, PSB/PSM and Nitrosobacter who build up the soil and provide nutrition to the plants. A well drained soil rich in leaf litter and low in rainfall receipt (like grass land) is the best for these aerobic organisms. If by chance, anaerobic bacteria gain in number in soil, the soil becomes degraded. The gum and cement producing bacterial products often block the soil pores. Such soils, if devoid of earthworms, become degraded soon.
In aquatic environs, bacteria also play a significant role. The toxic substance found in the fatty tissues and reproductive organs of Puffer fish, ‘tetradotoxin’, is the product of a microorganism and not the fish. Tetradotoxin is a powerful analgesic and is used in ‘pain relief’. Similarly, the anti leukemic compound found in the Tunicates (sea squirts) and even the anti microbial compound in the Caribbean coral reef sponges are also the products of microorganisms that are symbiotic to these hosts.
DNA cutting and splicing is carried out by an enzyme which remain active even at very high temperatures. This enzyme is obtained from a micro organism, Thermus aquaticus, isolated from hot water springs.
The natural process of decomposition is carried out by decomposers, who are, microbes, bacteria and fungi, who inhabit in all habitats.
Loss of the diversity of these microorganisms is caused by – Deforestation, ElNino-LaNina Southern Oscillation (ENSO) and Genetic contamination through creation of gene altered or transgenic microbes.
Life flourishes in the tropics, whether microbes or plants or animals. Most of Earth’s living form is represented by insects in general and beetles in particular. Although 1.4 million species of insects, 80% of all living forms are on record, tropical forests may contain as much as 30 – 50 million species of insects, some 97% of global biodiversity, living every where, from deep in the soil to the top of the trees, underground aquifers to within the feathers of the penguins in Antarctica, deep in the caves to our eye brows. Among the insects, beetles are the most speciose, the most pervasive, the most wide spread and dominant in all ecosystems and all habitats. They tunnel, mine and chew every substrate. Tropical biodiversity has not been fully studied, hence, it is essential to collect data, maintain inventory of all forms of tropical insects especially, beetles with samples. The samples so collected must be cold stored, identified and named using Alphanumeric Assessment System (QTES) and feeding the same to data base and taxasphere for formal identification. The same may be followed for other flora and fauna found in the tropical ecosystems.
- Mortality (death rate): is the rate at which death occurs in a population; Dispersal: is the rate at which individuals are immigrated or emigrated; Growth rate/form: is the sum total of natality, mortality and dispersal. Sex ratio & age structure: In most vertebrae populations, the sex ratio is primarily 50 male:50 female which, however, may vary between the populations. Age ratio: it determines the growth/decline in a population. For example: Rhesus monkeys of age group 1-3 years living on the road sides were trapped and exported in the 50s/60s for biomedical and pharmaceutical researches leading to their population decline when those in temple precincts were not. Life table: It is the tabular data on age structures based on a. Census data b. Mortality data from which ‘S’ shaped
survivorship curve is charted out by end users/insurance companies. Broadly, however, survivorship curves are of 3 types; a. convex type, where the population mortality rate is low until near the end of the life span as found in many species of large animals including man, b. concave type, where the population mortality is high during the young stages as in the profuse breeder species of both plants and animals and c. straight line type where the diagonal straight line curve indicates an age specific constant survival, a constant rate of mortality occurring at every stage as seen in hydra, gull and American robin etc.
Carrying capacity and Environmental resistance:
Every habitat and ecosystem has a specific space that can accommodate a certain number of individuals because of the limitations of space and food; and this is called the carrying capacity of the ecosystem. The ecosystem environment resists an increase in the density of populations as the fight for food, space and mate increase. The situation is further complicated by such factors as parasitism, prey-predator relationships and other such natural factors. The environmental resistance acts against the biotic potential of the organisms living in that ecosystem. An increase in the amount of struggles within the species and/or between the species leads to decline of their numbers, sometimes to near extinction. The decline and extinction of the Dinosaurs is a glaring example.