Biodiversity Loss.pdf Geo

BIODIVERSITY LOSS Biodiversity: Concept Human society depends on biological resources, their diversity and the ecosystems that sustain them to provide essential goods and services. Concept of Biodiversity: 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. DEFINITION: Biodiversity or biological diversity," generally refers to the variety and variability of life on earth. One of the most widely used definitions defines it in terms of the variability within

species,

between

species

and

between

ecosystems. Biodiversity refers to the variability’s among species of plants,

animals

and

microorganisms;

ecosystems;

ecosystem including terrestrial, aerial, marine and other aquatic system and ecological complexes of which they are part. In simpler terms, biodiversity is the assemblage of different life forms.



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Though the study of environment and ecology is quite old, the term biodiversity has been introduced by Walter Rosen in 1986. Thus, biodiversity is sum of all the genes, varieties, species, populations in different ecosystems and their relative abundance. Types of Biodiversity: Biodiversity is of three types: 1. Genetic diversity 2. Species diversity 3. Ecological diversity 1. Genetic Diversity: Each individual has specific characters, which is due to the genetic makeup or code. 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. In the recent decades, a new science named ‘biotechnology’ has emerged which studies the genes of species. 2. Species Diversity: 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

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bacteria, viruses, fungi, algae, etc. Certain regions support a more diverse populations than others. The regions that are rich in species diversity are called hotspots of biodiversity. 3. Ecological/Ecosystem Diversity: 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’. 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.

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: Alpha diversity: This is the diversity in species, i.e. the number of species within a community. This depends on the interaction



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between the biotic and abiotic factors and also takes into account immigration from other locations. Beta diversity: The term beta diversity was introduced by R.H. Whittaker in 1960. He defined it as “the extent of change in community

composition,

or

degree

of

community

differentiation, in relation to a complex-gradient of environment, or a pattern of environments”. Gamma diversity: This refers to the overall diversity and is applied to larger areas in which both alpha and beta diversity are measured. BIODIVERSITY LOSS- CAUSES Biodiversity change is caused by a range of drivers. A driver is any natural or human-induced factor that directly or indirectly causes a change in an ecosystem. A direct driver is a driver that unequivocally influences ecosystem processes and can therefore be identified and measured to differing degrees of accuracy. [Important direct drivers include habitat change, climate change,invasive alien species, overexploitation, and pollution.] An indirect driver is a driver that operates by altering the level or rate of change of one or more direct drivers. [Important indirect drivers include changes in population, economic activity, and technology, as well as socio-political and cultural



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factors.] A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely, by altering one or more direct

drivers.

Important

biodiversity

are habitat

direct

change, climate

drivers

affecting

change, invasive

species, overexploitation, and pollution. There are multiple drivers of biodiversity loss. Habitat loss and degradation Habitat loss and degradation create the biggest single source of pressure on biodiversity worldwide. For terrestrial ecosystems, habitat loss is largely accounted for by conversion of wild lands to agriculture, which now accounts for some 30% of land globally. In some areas, it has recently been partly driven by the demand for biofuels. The IUCN Red List assessments show habitat loss driven by agriculture and unsustainable forest management to be the greatest cause of species moving closer towards extinction. For example, in one recent study the conversion of forest to oil palm plantations was shown to lead to the loss of 73- 83% of the bird and butterfly species of the ecosystem. Infrastructure developments, such as housing, industrial developments, mines and transport networks, are also an important contributor to conversion of terrestrial habitats, as is afforestation of non-forested lands. With more than half of the



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world's population now living in urban areas, urban sprawl has also led to the disappearance of many habitats, although the higher population density of cities can also reduce the negative impacts on biodiversity by requiring the direct conversion of less

land

for

human

habitation

than

more

dispersed

settlements. Climate Change Climate change is already having an impact on biodiversity, and is projected to become a progressively more significant threat in the coming decades. Loss of Arctic sea ice threatens biodiversity across an entire biome and beyond. The related pressure

of

ocean

acidification,

resulting

from

higher

concentrations of carbon dioxide in the atmosphere, is also already being observed. Ecosystems are already showing negative impacts under current levels of climate change (an increase of 0.74ºC in global mean surface temperature relative to pre-industrial levels), which is modest compared to future projected changes (2.4-6.4 ºC by 2100 without aggressive mitigation actions). In addition to warming temperatures, more frequent extreme weather events and changing patterns of rainfall and drought can be expected to have significant impacts on biodiversity. Impacts of climate change on biodiversity vary widely in different regions of the world. For example, the highest rates of warming have been observed in high latitudes, around the



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Antarctic peninsula and in the Arctic, and this trend is projected to continue. Already, changes to the timing of flowering and migration patterns as well as to the distribution of species have been observed worldwide. In Europe, over the last forty years, the beginning of the growing season has advanced by 10 days on average. These types of changes can alter food chains and create mismatches within ecosystems where different species have evolved synchronized inter-dependence, for example between

nesting

and

food

availability,

pollinators

and

fertilization. Climate change is also projected to shift the ranges of diseasecarrying organisms, bringing them into contact with potential hosts that have not developed immunity. Freshwater habitats and wetlands, mangroves, coral reefs, Arctic and alpine ecosystems, dry and subhumid lands and cloud forests are particularly vulnerable to the impacts of climate change. Some species will benefit from climate change. However, an assessment looking at European birds found that of 122 widespread species assessed, about three times as many were losing population as a result of climate change as those that were gaining numbers. The specific impacts of climate change on biodiversity will largely depend on the ability of species to migrate and cope with more extreme climatic conditions.



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Over the past 200 years, the oceans have absorbed approximately a quarter of the carbon dioxide produced from human activities, which would otherwise have accumulated in the atmosphere. This has caused the oceans (which on average are slightly alkaline) to become more acidic, lowering the average pH value of surface seawater by 0.1 units. Because pH values are on a logarithmic scale, this means that water is 30 per cent more acidic. Pollution and nutrient load

Pollution from nutrients (nitrogen and phosphorous) and other sources is a continuing and growing threat to biodiversity in terrestrial, inland water and coastal ecosystems. Modern industrial processes such as the burning of fossil fuels and agricultural practices, in particular the use of fertilizers, have more than doubled the quantity of reactive nitrogen nitrogen in the form that is available to stimulate plant growth in the environment compared with pre-industrial times. Put another way, humans now add more reactive nitrogen to the environment than all natural processes, such as nitrogen-fixing plants, fires and lightning. In terrestrial ecosystems, the largest impact is in nutrient-poor environments, where some plants that benefit from the added nutrients out-compete many other species and cause significant changes in plant composition. Typically, plants such as grasses



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and sedges will benefit at the expense of species such as dwarf shrubs, mosses and lichens. Nitrogen deposition is already observed to be the major driver of species change in a range of temperate ecosystems, especially grasslands across Europe and North America, and high levels of nitrogen have also been recorded in southern China and parts of South and Southeast Asia. Biodiversity loss from this source may be more serious than first thought in other ecosystems

including

high-latitude

boreal

forests,

Mediterranean systems, some tropical savannas and montane forests. Nitrogen has also been observed to be building up at significant levels in biodiversity hotspots, with potentially serious future impacts on a wide variety of plant species. Large parts of Latin America and Africa, as well as Asia, are projected to experience elevated levels of nitrogen deposition in the next two decades. Although the impacts have mainly been studied in plants, nitrogen deposition may also affect animal biodiversity by changing the composition of available food. The number of reported dead zones has been roughly doubling every ten years since the 1960s, and by 2007 had reached around 500. While the increase in nutrient load is among the most significant changes humans are making to ecosystems, policies in some regions are showing that this pressure can be controlled and, in time, reversed. Among the most comprehensive measures to



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combat nutrient pollution is the European Union's Nitrates Directive . Overexploitation and unsustainable use Overexploitation and destructive harvesting practices are at the heart of the threats being imposed on the world's biodiversity and ecosystems, and there has not been significant reduction in this pressure. Changes to fisheries management in some areas are leading to more sustainable practices, but most stocks still require reduced pressure in order to rebuild. Bushmeat hunting, which provides a significant proportion of protein for many rural households, appears to be taking place at unsustainable levels. Overexploitation is the major pressure being exerted on marine ecosystems, with marine capture fisheries having quadrupled in size from the early 1950s to the mid 1990s. Total catches have fallen since then despite increased fishing effort, an indication that many stocks have been pushed beyond their capacity to replenish. Invasive alien species Invasive alien species continue to be a major threat to all types of ecosystems and species. There are no signs of a significant reduction of this pressure on biodiversity, and some indications that it is increasing. Intervention to control alien invasive species has been successful in particular cases, but it is outweighed by the threat to biodiversity from new invasions.



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In a sample of 57 countries, more than 542 alien species, including

vascular

plants,

marine

and

freshwater

fish,

mammals, birds and amphibians, with a demonstrated impact on biodiversity have been found, with an average of over 50 such species per country (and a range from nine to over 220). This is most certainly an underestimate, as it excludes many alien species whose impact has not yet been examined, and includes countries known to lack data on alien species. Overall, birds, mammals and amphibian species have on average become more threatened due to invasive alien species. While other groups have not been fully assessed, it is known that invasive species are the second leading cause for extinction for freshwater mussels and more generally among endemic species. Combined pressures and underlying causes of biodiversity loss The direct drivers of biodiversity loss act together to create multiple pressures on biodiversity and ecosystems. Efforts to reduce direct pressures are challenged by the deep-rooted underlying causes or indirect drivers that determine the demand for natural resources and are much more difficult to control. The ecological footprint of humanity exceeds the biological capacity of the Earth by a wider margin than at the time the 2010 target was agreed.



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TRENDS IN BIODIVERSITY LOSS: Contemporary examples of indices now in used in analyzing biodiversity loss include the Living Planet Index (LPI), the IUCN Red List of Threatened Species, and indicators that show us the state of specific habitats – such as forests – or the state of natural capital. Virtually all of Earth’s ecosystems have now been dramatically transformed through human actions. More land was converted to cropland in the 30 years after 1950 than in the 150 years between 1700 and 1850 . Between 1960 and 2000, reservoir storage capacity quadrupled and, as a result, the amount of water stored behind large dams is estimated to be three to six times

the

amount

held

by

rivers

.

Some

35%

of mangroves have been lost in the last two decades in countries where adequate data are available (encompassing about half of the total mangrove area). Roughly 20% of the world’s coral reefs have been destroyed and an additional 20% have been degraded. Although the most rapid changes in ecosystems are now taking place in developing countries, industrial

countries

historically

experienced

comparable

changes.



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The biomes with the highest rates of conversion in the last half of the 20th century were temperate, tropical, and flooded grasslands and tropical dry forests (more than 14% lost between 1950 and 1990). Areas of particularly rapid change in terrestrial ecosystems over the past two decades include the Amazon

basin

and

Southeast

Asia

(deforestation

and

expansion of croplands); Asia (land degradation in drylands); and Bangladesh, Indus Valley, parts of Middle East and Central Asia, and the Great Lakes region of Eastern Africa.



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Across the range of biodiversity measures, current rates of

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loss exceed those of the historical past by several orders of magnitude and show no indication of slowing. Trends in some 3,000 wild populations of species show a consistent decline in average species abundance of about 40% between 1970 and 2000; inland water species declined by 50%, while marine and terrestrial species both declined by around 30%.



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o

Biodiversity

o

is

declining

rapidly

due

to

land

use

change, climate change, invasive species, overexploitation, and pollution. These result from demographic, economic, sociopolitical, cultural, technological, and other indirect drivers. While

o

these

drivers

vary

in

their

importance

among ecosystems and regions, current trends indicate a continuing loss of biodiversity.



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CONSEQUENCES OF BIODIVERSITY LOSS The loss of biodiversity has many consequences that we understand, and many that we do not. The particular species making up an ecosystem determine its productivity, they affect nutrient

cycles

and

soil

contents,

and

they

influence

environmental conditions such as water cycles, weather patterns, climate and other no-biotic aspects.

Ø Problems

in

adaptation:

Fragmentation

of

habitats

reduces the capacity of species to adapt to climate change, by limiting the possibilities of migration to areas with more suitable conditions. Ø Weakening of ecosystems: Pollution, overfishing, climate change and ocean acidification all combine to weaken the resilience of coral reefs and increase the tendency for them to shift to algae-dominated states with massive loss of biodiversity. Increased levels of nutrients combined with the presence of invasive alien species can promote the growth of hardy plants at the expense of native species. Climate change can further exacerbate the problem by making more habitats suitable for invasive species. Sea level rise caused by climate change combines with physical alteration of coastal habitats, accelerating change to coastal biodiversity and associated loss of ecosystem services. Ø Ecosystem

functioning

and

human

well

being: 19

Ecosystems, whose functioning depends on biodiversity, provide the basic necessities of life (e.g.,

food, clean

water and air), offer protection from natural disasters and disease (e.g., by regulating climate, floods and pests), and shape human cultures and spiritual beliefs. Besides those provisioning, regulating and cultural services they provide, ecosystems also support and maintain life processes

such

as biomass production

and

nutrient

cycling (supporting services) which are essential to human well-being. Ø Decline in the quality of living environment: Out of the 24 ecosystem services that make direct contributions to human well-being, 15 are in decline. An indication of the magnitude of the combined pressures we are placing on biodiversity and ecosystems is provided by humanity's ecological

footprint,

a

calculation

of

the

area

of

biologically-productive land and water needed to provide the resources we use and to absorb our waste. The ecological footprint for 2006, the latest year for which the figure is available, was estimated to exceed the Earth's biological capacity by 40 per cent. Ø ORIGINAL CORAL AND BLEACHED CORAL –AN EXAMPLE



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Biodiversity loss disrupts the functioning of ecosystems, making them more vulnerable to perturbations and less able to supply humans with needed services. The consequences are often harshest on the rural poor, who depend most immediately upon local ecosystem services for their livelihoods. This will, in turn, affect the following: ✤ Demographic change ✤ Economic activity ✤ Levels of international trade ✤ Per capita consumption patterns, linked to individual wealth ✤ Cultural and religious factors ✤ Scientific and technological change The loss of traditional knowledge can be particularly detrimental in this regard, as for many local and indigenous communities biodiversity is a central component of belief systems, worldviews and identity. The impact of humans on the natural environment is significant and growing, causing changes in biodiversity that have been more rapid in the past 50 years than at any time before in human history. As demographic pressures and consumption levels increase, biodiversity decreases, and the ability of the natural world to continue delivering the goods and services on which humanity ultimately depends may be undermined.



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The richness and diversity of life on Earth is fundamental to the complex life systems that underpin it. Life supports life itself. We are part of the same equation. Lose biodiversity and the natural world and the life support systems, as we know them today, will collapse. We completely depend on nature, for the quality of the air we breathe, water we drink, climate stability, the food and materials we use and the economy we rely on, and not least, for our health, inspiration and happiness. By tracking the number of threatened species, the RLI quantifies overall risk of extinction and how it is changing over time. The RLI is based on IUCN Red List assessments that classify species into one of seven categories (Extinct, Critically Endangered, Endangered, Vulnerable, Near Threatened, Least Concern or Data Deficient). Entering

the

sixth

mass

extinction? Palaeontologists

characterize mass extinctions as biological or biotic crises defined by the loss of a vast amount of species in a relatively short geological time period. A mass extinction has occurred only five times in the past ~ 540 million years. Mass extinctions have occurred in response to changes in key environmental systems, for example in response to changes in climate or atmospheric composition, the availability of land at different latitudes or sea at different depths, or combinations of these. But in the last few centuries the Earth has experienced exceptionally high and increasing rates of species loss. Recent studies suggest probable extinction rates at present are up to



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100-1,000 extinctions per 10,000 species per 100 years, which is much higher than the long-term rate of extinction. PRESERVATION

OF

BIODIVERSITY:

The

need

of

preserving biodiversity is as follows: Because everything connects. The fate and prosperity of humanity is inextricably connected to the health and balance of the natural world. Every single organism plays a role in its ecosystem that contributes to the overall stability and health of that ecosystem. We depend on countless species directly for basic needs such as food, shelter, medicine, pollination and clothing, and on the complex network of all species which is necessary to support those species that we depend on directly. Science is only just beginning to understand the complex and subtle ways that species depend on each other for survival that leads

to

the

intricate

interdependency

of

ecosystems.

Maintaining biologically diverse ecosystems will help secure the indispensable ecosystem services that are often taken for granted. These include climate regulation, mitigation of floods, food, fresh water, carbon sequestration, purification of water and air, poverty alleviation, nutrient cycling in the soil, wood and fiber, pollination of crops and natural vegetation, fuel, disease management, seed dispersal, aesthetics and spirituality, and prevention of soil erosion. These essential services, effectively provided by healthy ecosystems, are what make our lives possible.



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Significance of Biodiversity: Values related to biodiversity can be grouped into three categories as below: Productive use: Biodiversity provides us many products, such as fuel, timber, fish, fodder, skin, fruits, cereals and medicines Consumptive use: Consumption value is related to natural products that are consumed directly, i.e., the goods which do not come under normal circulation of trade. 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. For e.g. the tribal people are completely dependent on the forests for their daily needs. Indirect use: They may provide us indirect benefits as non-consumptive values. Maintenance of ecological balance, conservation of natural resources and prevention of soil erosion may be considered as the examples of indirect use of biodiversity. Environmental Value: Healthy ecosystems are vital to life. The natural environment is responsible for the production of oxygen, maintenance of watercycle and other biogeochemical cycles.



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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. Productive Use Value: Through scientific breeding techniques animals giving better yield of milk, meat, etc. are being developed. The commonly used animal products used by the modem society come from the advances made in the fields of poultry farming, pisciculture, silviculture, dairy farming, etc. Even the fossil fuels like coal and petroleum are the products of biodiversity from the geological past. Most of the drugs and medicines used in the present times are extracted from different plant parts.



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Social Value: Due to modernisation, their habitats are being encroached upon and their very survival is at stake. It is ironic that the societies, whose whole life is intricately associated with the forests, are now not able to use the natural resources for their sustenance. The biodiversity in different parts of the world has been largely preserved by the traditional societies. Since the indigenous people always protect the forests for their own benefit, the Government should formulate plans to involve such people for environmental protection. 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. 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. 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



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life and provides some of the most beautiful aspects of our existence. Optional Value: This refers to the value of biodiversity that is yet unknown, but needs to be explored for future possibilities and use. Scientists have discovered and named about 1.75 million species, which is of utmost importance. We should preserve all the world’s biodiversity that can be used by the future generations. METHODS OF PRESERVATION AND CONESRVATION OF BIODIVERSITY: There are a number of conferences, treaties and individual efforts that can be are and can be attempted to preserve the world’s biodiversity. In this category, the Convention on Biodiversity (CBD) can be highlighted as the most dominant one.The Convention was opened for signature on 5 June 1992 at the United Nations Conference on Environment and Development (the Rio "Earth Summit"). It remained open for signature until 4 June 1993, by which time it had received 168 signatures. The first session of the Conference of the Parties was scheduled for 28 November – 9 December 1994 in the Bahamas. National parks and wildlife sanctuaries are some practical examples. Besides this, there are a number of national and international efforts to preserve and conserve biodiversity but there are a lot of clear efforts required by different countries of the world.



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