Biological Diversity

1. Introduction to biodiversity

The variety of plant and animals life on earth, including genes, species and ecosystems, is known as biological diversity. There are three major types of biodiversity.

(i) Habitat diversity (ecosystem diversity) – The variety of habitat types and biologic richness of those habitats in an ecosystem.

(ii) Genetic Diversity – The amount of variability that is available among the DNA of individuals with in a population or species. Genetic variability gives chances to species to compete, adapt, and survive.

(iii) Species Diversity – The concepts of species richness and evenness. Species richness refers to the number of species in a community. Species evenness is the relative abundance of individual within each species. 

2. The role of biological diversity in living systems

Biological diversity plays vital part in evolution of the new species. Evolution results from genetic variability, mutation and natural selection. For example, when individuals are force to adapt to a new environment whose characteristics allow and adaptation successfully to the changes they will survive and produce offspring with the same characteristics. The emergence of a new species by this process or other mechanisms is called speciation. 

A number of circumstances lead to the isolation of a group of individuals. For example, group of individuals could migrate across a river during a dry season and later when the water is higher they might be cut off from their native place or main population. This process is called divergent evolution. 

Biodiversity help to regulate the air, soil, and water purification and maintain their quality. Cycling of nutrients provides essential minerals for living beings. Examples are biogeochemical, nitrogen, sulphur and carbon cycles. Another natural process of decomposition is help to regulate the environment through breaks down the biodegradable matter into constituents. Biodiversity provides ecologic benefits also. For example, wetland provides variety of environmental services such as it’s a place for ground water storage and purifying toxins from soils and water. Rain forests act as a carbon sequestration. In addition biodiversity help for plant pollination. Insects, birds, bats and bees are important for much plant pollination. 

3. Threats to Biodiversity

3.1. Habitat loss and fragmentation of biodiversity

Biodiversity loss are caused by (i) habitat loss, fragmentation & degradation (ii) over exploitation (iii) pollution (iv) introduction of invasive species and (v) climate change

Habitat loss connected with direct destruction of habitats. Complete loss of the habitat means loss of the total occupying biodiversity in particular area. There are three types of habitat loss was identified (i) destruction (ii) fragmentation and (iii) degradation.

Fragmentation means breaking up a habitat ecosystem into smaller fragments or patches which have a smaller total area. Habitat fragmentation occurs when the size of natural habitat area is reduced or when that area is cut off and isolated by development activities. Fragmentation can damage the quality of habitat. For example some species require habitat into the forest interior and they can’t survive in the edge of forest or transitional zone because near the edge of forest ecosystem characteristics are similar into adjacent areas. This is called edge effect. New edge will occur when the forest area is clear by development activities. 

The subject of habitat fragmentation comes from island bio-geography. The Theory of Island Biogeography (Robert MacArthur and Edward Wilson) provides the relationship between area and the number of species (or species richness) which is described by the following equation.

S=CAz

 

S – Number of species in an island

A – Area of that island

C – Constant and will depend on both the taxon and the bio-geographic province

z – Fitted constant (with 0.15-0.35)

The basic principle of this theory is species diversity in an isolated area is balance with the loss of species through extinction and the arrival of new species through colonization (immigration). Briefly the S indicated here the rate of arrival of new species is equal to the rate of disappearance of species. 

An island is large and it located near the land it’s a place for large habitat diversity and support more species and greater chance to colonization and its give a path for low extinction. If an island is small and far away from the mainland it support for low species population and chance for low colonization and high extinction. 

3.2. Threats of extinction

In earth history life was being shape up by through extinction within a short geologically time. Several catastrophic episodes has influenced on species modification and extinction of disappear. For example dinosaurs became extinct 65 million years ago by a giant meteorite impact. Generally extinctions are caused by climatic change, volcanism or other catastrophic environmental changes. But human activities are become as a dominant factor for today’s extinction. 

An endangered species are the most vulnerable to extinction. Example includes the black rhino, Siberian tiger, giant panda, mountain gorilla and many others. A species show significant sign of decreases in population they will consider as endangered species. Example is the gray wolf and sea otter. Some species are more vulnerable and slow reproducers they will get more time to recovery from natural catastrophe or human exploitation. Some are require unique types of environment for their survival. Some species biologic and life style factors has influence on their living habitat. For example Panda lives only in specific places with certain conditions of environment. 

Illegal harvesting and over-exploitation of wild species for commercial allow to greatest threats to biodiversity. Animals and birds are hunting for their horns, feathers or any other various purposes. A rhinoceros or an elephant is hunt for their horns. Many exotic fish, birds and plants are transported illegally under poor conditions and they get die in that process. 

Introduction of exotic species is another major threat to biodiversity. Exotic species may flourish in the new environment and become as an invasive species. They take dominant place and wipe-out or force to migrated endemic species from their native place.

4. Conservation of biodiversity

Conservation biology is the applied science of maintaining the earth’s biological diversity. Susan Jacobson (1990) describes his structure of conservation biology in educational view. 

Fig: A Schematic view of the relationship between conservation biology and other disciplines (Jacobson 1990)

Conservation biodiversity requires mixture of approaches that include the concepts of conservation. The basic principle of biodiversity conservation depends on management of ecosystem. Managing ecosystem include protected area network, managing cultivated and built ecosystems and restoring the degraded ecosystems. There is important to ensure the habitat of species living without threatened. Providing resources (water, physical environment, supplying foods, etc……), control of predators, grazers, competitors and parasites which are cause threats to endangered species. 

Another technique is development of the zoos, aquaria and botanical gardens which are conserve the species through ex-situ conservation. The management of farms, forests, grasslands and wetlands also include the framework of biodiversity conservation. 

Another possible approach is tried to assign a value on ecosystem services – fresh water, clean air, recreational benefits and so on. First step for this process has to be valuing natural capital. Pavan Sukhdev, lead author of the 2010 The Economics of Ecosystems & Biodiversity (TEEB) report is saying ‘you cannot manage what you do not measure’. This is proposing with the value of changes of ecosystem service flows. The safeguarding ways is ‘designing payments for ecosystem services’ and going with the communities and land owners who need to be pay considered to keep wetlands and forests intact. In Mexico deforestation has been halved by 2003 law that allowed paying water charges by land owners and willing to reduce the agricultural clearances.

In other countries design ‘biodiversity credits’ that offer a rewarding to people that those who willing to have desire to protect and manage biodiversity habitats. In New South Wales, the state government department has setup a ‘Bio Banking’ scheme for developers and land owners those can trade biodiversity offsets.

Protecting natural ecosystems can enhance the value for money in direct sense (E.g. Protected areas….). But this approach is depending on effective way of implementation. Force of law is the practical work to adapt these strategies. The Convention on Biological Diversity, Convention on Climate change adapted a strategic plan for the decade to 2020 is ‘Living in harmony with nature’. The plan directs by governments and takes actions to restore biodiversity and ecosystem services through protected areas, habitat restoration, species recovery programs and other targeted conservation interventions’.

References:

1. Barbara murck (2005); Environmental Science – A self-Teaching guide; John wiley & sons; Inc; USA

2. Mark Lynas (2012); The God species – How Humans Really can save the planet……; Fourth Estate; London

3. http://www.algebralab.org/practice/practice.aspx?file=Reading_IslandBiogeography.xml
4. http://www.geolounge.com/island-biogeography/

Air Pollution

       Definition of Air pollution 

Air pollution occurs when the substances are in excessive level that could be harm to the human health, animal and affect plant growth. These substances are known as ‘air pollutants’.

Air pollution means that any substances emitted into the air from an anthropogenic, biogenic or geogenic sources which are adversely affects to human, plant, animal and causes damage to property. “Air pollution is the excessive concentration of foreign matter in the air which adversely affects the wellbeing of the individual or causes damage to property” – American Medical Association.

       Sources and classification of air pollutants

Pollutant can be classified as primary and secondary air pollutants. Primary air pollutants those emitted directly into the atmosphere. The main primary air pollutants are

Carbon compounds, such as CO, CO2, CH4 and VOCs

Nitrogen compounds, such as NO, N2O, and NH3

Sulfur compounds, such as H2S and SO2

Halogen compounds, such as chlorides, fluorides and bromides

Secondary air pollutants means those are not emitted directly into the atmosphere from sources. The main secondary pollutants are;

NO2 and HNO3 formed from NO

Ozone (O3) formed from photochemical reactions of nitrogen oxides and VOCs

Sulfuric acid droplets formed from SO2, and nitric acid droplets formed from NO2

Sulfates and nitrates aerosols formed from reactions of sulfuric acid droplets and nitric acid droplets with NH3

Organic aerosols formed from VOCs in gas-to-particle reactions

     Effects of Air pollution

     Impact on Human Health

The air we inhale has a quantitative and qualitative balance that maintains wellbeing of human health. When this balance is disturbed or if it purity get polluted it may cause adverse impact on human health. All impurities do not harm. It depends on various factors / pollutants and their concentrations in the air.

Nature of the pollutants

Concentration of the pollutants

Duration of exposure

State of health of the receptor / Individual susceptibility

Air pollution can cause by both naturally and from man-made sources. Man-made sources include industries, automobile and power generation. Major indoor air pollution sources are tobacco smoke and combustion of solid fuels for cooking and heating. 

Health effects occur due to the contact between the body and the pollutants. Exposure of air pollution can cause acute (short term) and chronic (long term) health effects on human. Acute effects are immediate and reversible. It includes common health effects. Such as eye irritation, headaches. Chronic effects are take time to visible and not reversible. It cause decreased lung capacity and lung cancer which result from long-term exposure of toxic air pollutants. 

Air pollution can also indirectly affect human health through acid rains. It enters to the human body through polluted water and food chain. Acid precursors are airborne pollutants and they form acids through oxidation and chemical interaction with water vapor in the atmosphere. 

Approaches to measuring health impacts of air pollution

Three methods are available for measure the impacts of air pollution on people. They are;

Individual exposure levels

Clinical studies

Epidemiology

Individual exposure levels to air pollutants dependent on concentrations and dosages of air pollutants, state of health and duration of exposure of the body. Effects observation includes respiratory diseases, irritation of eyes, and reduction in physical activity and many other physiological responses. Generally the effects of air pollutants related with the state of health and age group of the individual. For example exposure of pollution becomes risk for those who have chronic diseases of the lungs or heart. 

Clinical studies involve who are exposed to air pollution under uncontrolled conditions. The studies of truck drivers, traffic policemen and factory workers can give valuable information about the vulnerable occupational group of people. It also includes the observation of polluted areas data. Epidemiology mainly involve the study of the distribution of specific diseases and the determine factors. 

      Impacts on plants 

Air pollution has adverse impact on plants and animals. Sulphur dioxide, various pesticides and new industrial processes are the main sources for the pollutant that cause complete destruction of vegetation.

These pollutants interfere with plant growth and the phenomenon of photosynthesis. Exposure to air pollution in plants cause acute injury and chronic injury. The damage reach the plant through leafs. It takes several forms.

Necrosis – Killing or collapse of tissue

Chlorosis – loss or reduction of the green plant pigment, chlorophyll

Abscission – Dropping of leaves

Epinasty – Downward curvature of the leaf due to higher rate of plant growth

       Effects of air pollution on animals 

Farm animals exposed to pollution in two ways. (i)  Accumulation of air-borne contaminant in the vegetation and forage. (ii) They get poisoning when they eat contaminated vegetation. Fluorine, arsenic and lead are the three main pollutants cause damage to livestock. 

Cattle and sheep are the most vulnerable animals to fluorine toxicities. Fluorine poisoning cause lack of appetite, rapid lose in weight, decline in health and vigour, lameness, periodic diarrhea, muscular weakness and death, general ill health due to malnutrition, lowered fertility, reduced milk production and growth retardation. 

Arsenic occurs due to various industrial process and smelters. Arsenic in dusts or sprays on plants can lead to poisoning of cattle; symptoms of arsenic include severe salivation, thirst, vomiting, feeble and irregular pulse and respiration. It affects animal central nervous system and cause dull, lack of appetite and weight loss in animals. 

Smelters, coke ovens and other coal combustion process are the main sources for air-borne lead. Lead poisoning causes prostration, staggering and inability to raise symptoms. Animals pulse gets weak and some may fall suddenly stiffens in legs, and have convulsions. Other symptoms in cattle are grinding of the teeth and rapid chewing of the cud. 

Pollution is now beginning to affect domestic animals also. Many dogs suffer from coughs, nose and throat diseases due to increasing air pollution. 

      Air quality Management 

Poor air quality adversely affects the productivity of people and national economic growth. Therefore take action to minimize the air pollution. Air quality management includes various aspects of pollution control measures. Industrial expansion is the major contributor of air pollution. Another significant pollution sources are vehicular traffic and thermal power generation. 

In transport sectors air pollution increase due to poor maintains of vehicles and they accelerated air borne particles in atmosphere. High traffic congestion of vehicles usage increases the emissions of carbon monoxide and volatile organic compounds. Therefore proper air quality monitoring system and transport management system are require for maintain the air quality. 

Reduce gasoline consumption: Reduce daily usage of vehicle transport. Use public transport and take walk, bike are the practical solutions to mitigate the air emissions. Replace the outdated fleet of buses, old engines rains and introduce electric trains to reduce the CO₂ emission through fuel saving. Establish an enforcement of vehicles emission standards, fuel emission standards and emission standards and implement a vehicle emission testing programs to mitigate air pollution.

Emission from industrial sources can control through adopt a modified technologies. Many of the industries use outdated technology and cannot adopt new technology or pollution control equipment due to lack of physical space for installation which was established prior to 1980. But many governments started industrial process with environmentally – friendly technologies. Reduction of CO2 emission can be achieved through fuel switching by improving combustion. 

Air pollution mitigation requires both global and local coordination. The European Union established an Emission Trading Scheme (EU ETS) to reduce emissions from power plants and large industries. In addition European commission introduced an Energy Efficiency Action plan in October 2006 to reduce the energy consumption by 20% in 2020. Developing countries are making effort to reduce their emissions by adopting domestic and international policies to increase efficiency, expand renewable energy and promote sustainable development.

The Kyoto protocol treaty which was adopted by the United Nations Framework Convention on Climate Change (UNFCCC) established to limit the greenhouse gases. The Kyoto protocol introduced three flexibility mechanisms for developed countries to achieve their emission reduction targets. They are Clean Development mechanism (CDM), Joint implementation (JI) and Emission Trading (ET). Under this treaty Carbon Trading international market introduced as a global strategy to traded reductions of greenhouse gases at international market at competitive prices. 

 The clean Development Mechanism (CDM) is the only mechanism that both developed and developing countries can participate. Implementing projects in developing countries that reduces the GHG emissions and selling the amount avoided to developed countries is called CDM or Carbon trading. 

Carbon trading can be undertaken by implementing two types of projects: Emission avoidance projects and Green House Gas Removal or Sink projects. Clean Development mechanism (CDM) or sink projects include forestry for carbon trading. Forests provide a mechanism of carbon sequestration. Afforestation and reforestation projects are eligible for forestry CDM according to Bonn agreement.

References:

1. Global Warming & Environmental Threats; Economic review (June/July 2008); A peoples Bank Publication. 

2. Barbara Murck (2005); Environmental Science ; John Wiley & Sons, Inc; USA

3. Kevin T. Pickering an Lewis A.Owen (1997); An introduction to global environmental issues; London and New york 

4. http://charityguide.org/volunteer/fewhours/global-warming.htm