A2 Geography- Biodiversity

MEA 4 Future scenarios (1)

1. GLOBAL ORCHESTRIATION (world becomes more globalised - reactive management) In this scenario all trade barriers and subsidies are removed to allow free trade. Economic growth is high and the standard of living in poorer countries improves. Poverty and inequality are reduced, and public goods such as infrastructure and education are invested in. The assumption is made that as wealth increases there will be the money and the will to deal with environmental problems (reactive management), but it may be too late. High biodiversity loss is predicted in this scenario.

Alternative to hotspots

As more natural systems are coming under pressure from development and/or population growth, the World Wide Fund for Nature (WWF) has developed the concept of the ECOREGION. This is a broader concept than the hotspots approach and covers the full range of the earth's habitats so that conservation is more comprehensive. Each of the 238 ecoregions covers a large area, within which are a characteristic group of species for that habitat type.

Ecosytems process

Carnivores (tertiary consumers) ^ Carnivores (secondary consumers) ^ Herbivores (consumers) ^ Plants (producers) ^ ABIOTIC (non living e.g. sunligth, soil and carbon dioxide)

Net Primary Productivity

Net Primary Productivity is what is available to the rest of the ecosystem.

MANAGING BIODIVERSITY Sustainable yield

SUSTAINABLE YIELD is a key part of sustainable management of ecosystems. It represents the 'safe' level of harvest that can be hunted/caught/utilised without harming the individual ecosystem.

Global Ecoregions

The Global Ecoregions is a science-based global ranking of the Earth's most biologically outstanding terrestrial, freshwater and marine habitats. It is the first comparative analysis of biodiversity to cover every major habitat type, spanning five continents and all the world's oceans. The aim of the Global Ecoregions analysis is to ensure that the full range of ecosystems is represented within regional conservation and development strategies, so that conservation efforts around the world contribute to a global biodiversity strategy.

Global distribution of biodiversity

The highest levels of biodiversity generally occur in the tropical countries e.g. Brazil, Ecuador and Indonesia. These are nearly all developing countries, with the least resources to support sophisticated conservation strategies to tackle biodiversity loss. Species diversity is least in areas at high latitude (e.g. Iceland) and in desert areas (e.g. Qatar) where there are more LIMITING FACTORS. This is due to lower levels of solar energy in high latitude areas and lower temperatures. Also a lack of moisture in desert areas

International institutions

There are also international institutions with a specific focus such as the ITTO. This is the INTERNATIONAL TROPICAL TIMBER ORGANISATION. It has been working with timber companies working in the rainforest to encourage sustainable forestry. The FSC (Forest Stewardship Council) has similar aims and it has come up with a logo to show consumers wood products that come from sustainable sources. FSC is an independent, non governmental, not for profit organisation established to promote the responsible management of the world's forests. Products carrying the FSC label are independently certified to assure consumers that they come from forests that are managed to meet the social, economic and ecological needs of present and future generations.

Importance of hotspots

They are used as a tool to assess conservation priorities, i.e. to see where there is a high biodiversity that is under threat. They are important because they contain a wide range of species, often in quite small regions. They have a significant number of endemic species, and are threatened with ecosystem loss and disappearing numbers. If they are not protected, the survival of a large number of organisms is threatened. If we lose hotspots we lose potential resources; we will suffer high rates of extinction and global biodiversity will decline.

Economic Development and Ecosystem State

1. An area with the least economic development (LDC): • Little large scale resource extraction or ecosystem removal. • Low population growth. • Much of the natural ecosystem is still intact and relatively undisturbed. 2. Economic development is likely to be rapid (LEDC): • Manufacturing industry will be growing quickly. • Resource extraction, tourism and urbanisation will cause ecosystem removal and degradation. • Pollution may be considerable. • Government focus is likely to be on increasing development and living standards. 3. An economy possibly driven by tertiary industry (MEDC): • Conservation issues are likely to get more publicity and more funding. • The population may be large but growth, if it occurs, will be slow.

MEA 4 Future scenarios (2)

2. ORDER FROM STRENGTH (world becomes more regionalised - reactive management) In this scenario, protection of national boundaries is paramount. Rich countries will close their borders, attempting to confine poverty, conflict, environmental degradation and destruction of ecosystem services to areas outside their borders, in order to protect their own standard of living. Problems of ecosystem degradation will worsen, especially in poorer countries as people struggle to survive. Economic growth rates are lowest here and ecosystem management is reactive. Ecosystem collapse is predicted, however, this will not recognise national borders, and globally, biodiversity loss will be greatest in this scenario.

MEA 4 Future scenarios (3)

3. ADAPTING MOSAIC (world becomes more regionalised - proactive management) In this scenario, ecosystems are locally and regionally managed. Ecosystems are managed proactively, on a local scale, making management more sustainable. People work cooperatively to try and develop economically but also to maintain ecosystems. As this occurs, wealth increases steadily, but some ecosystem damage occurs as people try to discover the best way to develop sustainable use.

MEA 4 Future scenarios (4)

4. TECHNO GARDEN (world becomes more globalised - proactive management) In this scenario, people use technology to maximise the ability of ecosystems to provide services. The world is highly connected and ideas are shared. Strategies are developed to gain multiple services from the same ecosystem without permanent harm, and a proactive approach to management is taken. Wealth increases for poor countries as knowledge and technology are shared. There could be problems with over reliance on technology, and the success in increased production of ecosystem services could compromise the ability of ecosystems to support themselves, resulting in biodiversity loss.

Biodiversity hotspots

A biodiversity hotspot is an area containing a huge number of species, many of which are ENDEMIC. Hotspots have been described as 'the most remarkable places on Earth and the most threatened.' They cover less than 3% of the Earth's surface, yet contain 44% of the world's plant species and 35% of its animal species. By definition , biodiversity hotspots are under threat, having lost 70% of their original vegetation cover

Key players and biodiversity

A range of players have a role in managing biodiveristy. They can operate at a variety of scales, with LOCAL players being most closely involved because of their likely dependency on biodiversity for their wellbeing. However, many people argue that the GLOBAL or international players wield the greatest power. Some groups are committed to conservation while others rely on exploiting the resource, though not always for the same purposes.

Threats to biodiversoty (1)

Although there is a degree of correlation between the areas with highest biodiversity and those areas where there is the most threat, there are other areas, where, although the level of biodiversity may not be great, the threats against them are major and may result in extinctions. Tundra areas, which are not highly biodiverse, are under severe threat from global warming, and species such as the polar bear are facing extinction.

Biodiversity Futures

At present only 12% of land and 1% of the sea has some form of protection, and protected areas are unevenly distributed and fragmented. In many LEDCs there are well preserved ecosystems but little money to conserve them. Those areas that are declared 'protected' are not necessarily well managed and could be subject to poaching and degradation. Effective conservation needs an efficient, trained ranger service, scientific monitoring of habitat health, and an understanding of the 'mechanisms' of habitats and their ecosystems. Outside protected areas, global threats such as pollution, climate change, invasive alien species and unsustainable development continue to threaten biodiversity.

Gloabl threats to biodiversity

Climate change is a huge threat. Sea level rises, migration of species as they try to adapt. Disappearance of some habitats. Increase in storms / hurricanes. Habitat destruction and degradation is a major threat linked to population growth and economic development i.e. agriculture, HEP, deforestation etc. 25% of the Earth's surface is used for cultivation, and this is set to increase as population grows. There are also wider environmental impacts e.g. increased soil erosion and flooding. Pollution is mainly from human activities. Acid rain from burning of fossil fuels damages lakes and forests. Ozone depletion by CFCs. Desertification - some 10-20% of drylands are already degraded. Caused by climate change, over-grazing and poor farming practices. Over-exploitation by taking out resources faster than they can be replaced. Illegal logging, overfishing and the wildlife trade. This problem is aggravated by population pressure, poverty and the need to produce food.

Economic development and ecosystem degradation

During the 20th century and into the 21st, many countries shifted from having economies based on primary industries (especially agriculture), to mixed economies including manufacturing and service industries. This has put incredible pressure on their ecosystems as natural resources were extracted. Even in countries at an earlier stage of industrial development, population growth has meant using whatever resources they have in order to support the economy and provide for their citizens.

Extinction effecting food chains

Extinction will have an impact below and above the extinct species. Some species may be fundamentally important for the survival of an ecosystem, they are called KEYSTONE SPECIES. Species that were eaten by the extinct species may become more numerous, perhaps to the detriment of other parts of the ecosystem. Species that ate the extinct species will suffer, especially if they have a restricted diet. Some species live in a symbiotic relationship with another species, extinction can threaten them.

Local threats to biodiversity

Fire as large-scale burning can cause a loss of biodiversity, destroying rare ecosystems and species. Habitat fragmentation caused by road building, settlements, mining, ranching, agriculture etc can result on pockets of natural system left isolated in areas of human activity. This is sometimes known as ISLANDISATION. Species are at greater risk of extinction e.g. as a result of predation, as animals are more exposed to threats due to their smaller and disconnected habitats. Recreational use. Plants are vulnerable to trampling and erosion, and animals are vulnerable to disturbance. It could lead to an increased risk of wildfires. Mineral exploitation can be particularly damaging and disruptive, with open-cast extraction leaving huge holes and toxic spoil heaps scarring the landscape. Pollution. Runoff into rivers and wetlands from nitrogen fertilisers leads to increased algal blooms and EUTROPHICATION, whereby falling oxygen levels leads to the death of plants and animals and causes the food chain to collapse Alien Species as the invasion of non-native species has been responsible for at least half of extinctions since 1600, and islands have suffered the most. Species are introduced to regions where they have fewer or no natural predators, and can out-compete indigenous species e.g. grey and red squirrels in UK.

Economic value

Food supply - 90% of calories in the human diet come from 30 plants. Medicines - 25% of all drugs are from plants e.g. Rosy periwinkle used to treat Leukaemia. Pollinators, such as bees, are needed to help maintain fruit orchards etc. Can help reduce the financial impact of floods.

Factors threatening biodiversoty (2)

Global warming will not only lead to increases in temperature and changes in rainfall, but also to more damaging and frequent extreme weather events, such as floods, storms and droughts. It will also have indirect effects through sea-level rises and increased risks from pests and diseases. It is predicted that a 1oC rise could mean that 10% of land species face extinction, a 20C rise leading to 15%-40% of land species facing extinction, and a 30 C rise causing between 20%-50% of land species to face extinction.

Global protection

Globally, both the total area and the number of protected sites are steadily growing. Some countries, such as Tanzania, New Zealand, Ecuador and Poland, now have over 25% of their land area protected. At the same time, there has been a change in the type of conservation strategies used, and therefore the type of protected area.

Gross Primary Productivity

Gross Primary Productivity is all the energy or organic compounds created. Not all of this is available to the rest of the ecosystem (herbivores, decomposers etc) as some is used by the plant itself.

Factors and process influencing biodiversity

Growth in human population has an impact on biodiversity because we are in direct competition with other species for space and resources. Size, climate, altitude, isolation, pollution, urbanisation, hunting. Climatic extremes tend to have low levels of biodiversity because there are not enough food sources to support large populations, and often only specialised organisms can survive

Ecological/environmental value

High levels of biodiversity make ecosystems more stable and less vulnerable to change. Plants' ability to photosynthesise provides the base for food chains. Ecosystems act as carbon sinks. Plants play an essential role in the hydrological cycle, and can reduce flood impact

CARRYING CAPACITY

In order to manage wildlife, or more usually fisheries, mathematical models have been developed to estimate the CARRYING CAPACITY. This is the maximum human population that can exist in equilibrium with the available resources (food, nutrients etc.) The major problem is that carrying capacity varies seasonally, and over time may be reduced by climate change. One problem with this approach is that what constitutes a 'safe' harvest is subjective, and it may take many years to establish if a species numbers are declining, by which point it may be too late

Local players

In some areas, such as the Amazon rainforest, indigenous people may be totally dependent on an ecosystem for their survival. They can be effective campaigners for ecosystem preservation. Sometimes indigenous people can work in harmony with big business in schemes such as ECOTOURISM where they can act as guides. Local communities of fishermen and farmers frequently have strong views about conservation, as it conflicts with their subsistence. In the UK, local people's interests have often conflicted with those of the wider community. Local people have objected to initiatives such as the expansion of Heathrow airport and the Newbury bypass. Biodiversity management can be run very successfully on a local level e.g. through county wildlife trusts such as the Lancashire Wildlife Trust. These are small-scale NGOs that have developed their own BIODIVERSITY ACTION PLANS (BAPs) to involve local people in conservation.

Biosphere reserves

In the 1980s, concepts such as the UNESCO Biosphere reserve model was developed. It is now one of the most common forms of conservation management. Biosphere reserves use the principle of zoning to conserve core ecological areas, whilst allowing some economic development, such as eco-tourism or managed hunting or logging, in buffer zones surrounding the core area. Local people are educated to enable them to use more sustainable agricultural techniques, and conserve resources for future generations. Careful thought is given to the design and distribution of reserves. For example, in an era ofclimate change, current thinking favours the creation of large reserves connected by open corridors running in a north-south direction to allow the maximum migration of species driven polewards by global warming

Future Scenarios Millennium Ecosystem Assessment (MEA)

In the early 21st century, the MEA (initiated by the UN) investigated the state of the world's ecosystems. The objective was to assess the consequences of ecosystem change for human well-being and the scientific basis for action needed to enhance the conservation and sustainable use of those systems and their contribution to human well being. The MEA came up with 4 future scenarios that assumed continued biodiversity loss over the next 50 years, but suggested that the different approaches would have different results for human and ecosystem wellbeing. The MEA outlined: • 2 development pathways - one in which the world becomes increasingly globalised, and one in which the world becomes increasingly regionalised. • two approaches to ecosystem management - one in which actions are reactive and most problems are only addressed after they become obvious, and one in which actions are proactive and policies seek to manage ecosystems for the future.

Distribution of hotspots

Initially , 25 terrestrial hotspots were identified. This has recently been updated, and there are now 34 hotspots, including marine hotspots. Hotspots are often within or near the tropics, due to the favourable climatic conditions for plant growth, factors such as high temperatures, plenty of sunlight and sometimes high rainfall. Some hotspots are geographically isolated areas: islands and small continents. There is often considerable variation in physical characteristics such as altitude, geology and soil type.

Destruction and degredation of ecosystems

It is important to distinguish between the destruction of an area of an ecosystem (total clearance), and degradation (loss of quality). Degradation could include the loss of some species (loss of biodiversity,) or the loss of biomass (volume of living matter). While the two are usually linked, there are some ecoregions that have not decreased in extent, but have become very degraded. PRISTINE areas do not show significant signs of human impact. DEGRADED areas may have some elements of the natural ecosystem but the area will have been substantially altered by human activity. PROTECTED areas are where conservation of the natural environment takes place to preserve wildlife and possibly return an ecosystem to a more natural and diverse state.

National Parks

National Parks are often referred to as EXTRACTIVE RESERVES as conservation takes place at the same time as the extraction of natural resources. They have high profile and allow access to spectacular landscapes, whilst also preserving biodiversity and cultural diversity. In the UK there are 15 National parks which are part of a global family of over 113,000 protected areas, covering 149 million square kilometres or 6% of the Earth's surface. The Peak District was the first park to be designated in 1951, with a total of 10 parks designated by the end of the 1950s. Since 2000, 4 more parks have been designated, with the most recent additions being the New Forest in 2005, and the South Downs in 2009.

National players

National governments have a huge impact on ecosystems, acting as both regulators and facilitators. The UK government is responsible for planning permission and laws that govern acceptable levels of air pollution, water pollution and land contamination. Protected areas may be set up such as National Parks. Taxation and subsidies may also influence ecosystems. For example in the UK, farmers that plant deciduous woodland, or preserve wetlands and meadows, are entitled to government subsidies

Threats to biodiversity (2)

Of all the species that have ever existed, 99.9% are now extinct. Many of them perished in 5 cataclysmic mass extinction events, and ecologists are concerned that we are on the brink of another mass extinction, with human population playing a key role. Audits (examinations) of the Earth's ecosystems report an increasing rate of habitat destruction and species extinctions, and therefore widespread biodiversity loss.

Factors threatening biodiversity (1)

One of the greatest threats to biodiversity is global climate change. The Stern Review (2005) argues that climate change is likely to occur too rapidly for many species to adapt. In the last 25 years, species having been moving polewards by an average of 6km per decade. Some species cannot move quickly enough. Seasonal events such as flowering, egg-laying, fruiting are starting to occur earlier in the year, and it can be hard for species eating these things to adapt quickly enough.

Ex Situ Consveration

One option for endangered species is to establish a captive population away from its natural habitat. This includes captive breeding with release schemes, and biodiversity banks such as genetic and seed banks in zoos and botanic gardens. Several species have been saved this way including the Giant Panda. Ex situ and in situ conservation are not rivals, but work together to increase endangered populations and re-establish near-extinct ones. Zoos can provide stock to release and funds for conservation from ticket sales. Captive stock can be used to educate people on hotspots, endemism and endangered species. Captive breeding buys time but is expensive and can only look after relatively few of any one species. Zoo environments can also cause severe stress for some species, they may not breed successfully, and releasing endangered species back into the wild is problematic.

Primary Productivity

Primary Productivity is the ability of plants to produce organic compounds from carbon dioxide by photosynthesis. This creates energy for the rest of the ecosystem.

Cultural value

Recreational use, adds to quality of life. Education and scientific research, expanding our understanding of the natural world. Supporting lives of local peoples and helping maintain traditional cultures. Ethically we should be able to pass on the same resources we have had access to.

NGO'S

Some NGOs operate internationally such as Greenpeace and WWF: Greenpeace is working to reduce climate change, reduce pollution and preserve oceans. It often uses direct action. The WWF operates in more than 100 countries. Its main aims are to save biodiversity, and reduce humanity's impact on natural habitats.

3 key elements of biodiversity

Species Diversity - the number of different species within an area. Genetic Diversity - this refers to the genetic diversity within species. Ecosystem Diversity - the range of different ecosystems in an area.

CASE STUDY Sustainable yield management Southern Ocean Fisheries

The Southern Ocean encircles Antarctica and accounts for 10% of the world's ocean. Thanks to the Antarctic Treaty System (1961), the fisheries are now sustainably managed. Before this, the fishing grounds were overharvested by fleets of Soviet trawlers. This led to the extinction of many species of fin fish. The model used to calculate fishing yield is one of the most sophisticated because of its three-pronged approach: The SINGLE SPECIES APPROACH sets limits for harvesting individual species that are indefinitely sustainable. The ECOSYSTEM APPROACH involves considering harvested species both on their own and in relation to dependent species and the whole environment. The PRECAUTIONARY PRINCIPLE aims to model the consequences of any planned expansion of catches before it is permitted.

Future Scenarios World Wildlife Fund's Living Planet Report

The WWF has attempted to model possible future scenarios based around the concept of ecological footprints. The WWF attempted to model ways of ending the ecological deficit (overshoot) - the amount by which the ecological footprint exceeds the biological capacity of the space available to that population. 2 possible pathways were outlined: • Actions to reduce ecological footprint. • Ways to maintain / develop biological capacity. On the basis of these two pathways, WWF anticipates four possible scenarios: 1. Business as usual, leading to an increased ecological footprint and no reduction in the 'overshoot' or the degree to which consumption exceeds biological capacities. 2. Slow shift, gradually reducing the ecological footprint by developing many sustainable policies so that biological capacities recover by the year 2100. 3. Rapid reduction, with radical policies to control ecological footprints, leading to elimination of the overshoot by 2040. 4. Shrink and share, breaking down the world into regions in order to share the responsibility of controlling the overshoot by global co-operation

Individual players

The attitudes of individuals are very diverse. Some people are relatively unconcerned by ecosystem loss while others value natural ecosystems for their spiritual value. Consumers can influence ecosystems through ethical consumerism where people choose to buy environmentally friendly products like recycled paper or dolphin-friendly tuna. Individuals such as divers, birdwatchers, fishermen or mountaineers collectively can cause degradation and damage in high quality ecoregions and hotspots. Scientists and researchers play a vital role in monitoring the state of biodiversity and enhancing its quality. Some, however, are paid to find new products for pharmaceutical companies, which can lead to conflict with indigenous peoples.

Trophic levels (2)

The basis of an ecosystem comes from the ABIOTIC (non-living) elements: sunlight, water, carbon dioxide and nutrients in the soil provide what plants need for growth. Through photosynthesis plants produce chemical energy from sunlight therefore they are producers. Producers are also called AUTOTROPHS as they produce their own energy. Higher levels consume energy from the level below - hence the term consumers. Consumers and decomposers are also called HETEROTROPHS as they consume energy produced by something else. At each energy level (trophic level) energy is used by the organisms activity e.g. movement, respiration, excretion. The trophic levels show a food chain but in reality it is likely to be a more complex food web. Biomass describes the total living mass at each trophic level; this declines as you move up the food chain due to species using some energy to survive. That is why each level is shown as smaller than the one below. DECOMPOSERS can work at any level of producer or consumer. They help decomposition of dead matter e.g. fungi and bacteria. DETRIVORES eat dead matter e.g. Woodlice.

Differences in conservation

The relationship between wealth and ecosystem conservation will not be this simple in reality. Countries will develop in different ways, focusing on different areas of their economy. One country may have a lot of mining whereas another country may focus on tourism; this will affect the state of their ecosystems. Even if countries develop in similar ways, some government policies to protect ecosystems will be more successful than others.

Restoration

The restoration of highly degraded ecosystems is the ultimate conservation challenge. Restoration can include creating wetlands (river restoration) or linking up small fragments of reserves to produce a larger, more climate-proof reserve. These reconnection schemes require costly land purchases, so they have to emphasise local benefits such as recreation. Restoration of derelict sites such as soil heaps, mines and quarries is even more expensive because the ecosystem and habitat have to be virtually reconstructed from scratch. A lot depends on how readily plants will reseed and how polluted the land is.

Value of Ecosytems and Biodiversity (2)

The value can also be divided into PROVISIONING SERVICES, REGULATIONG SERVICES, CULTURAL SERVICES, and SUPPORTING SERVICES: Provisioning services (also known as goods) are products derived directly from the ecosystem e.g. timber for fuel and building, or fruits, meat and fish for food. Regulating services are those which are vital to the functioning of the Earth's systems e.g.forests act as the 'green lungs' of the world and as important carbon sinks.Trees remove carbon dioxide from the atmosphere and release oxygen. They also protect against flooding and soil erosion. Cultural services provided by ecosystems include the aesthetic and spiritual enjoyment that people draw from them and opportunities for recreation. Supporting services include processes such as nutrient cycling, soil formation and primary production that are vital to the well being of the ecosystem itself. They also include the provision of wildlife habitats. These are NOT services that support people.

Value of Ecosytems and Biodiversity (1)

The value of biodiversity and ecosystems refers to the cultural, environmental value as well as its economic value. The value of ecosystems can be divided into DIRECT and INDIRECT: Direct uses (goods) are things that can be produced and consumed e.g. food, fuel, medicine, timber etc. Indirect uses (services) include soil formation, supporting the food chain on which we depend, and the role that plants play in the hydrological cycle.

Global players

There are over 150 international conservation treaties. International treaties are usually about funding conservation work, designating protected areas and regulating trade in endangered species. THE RAMSAR CONVENTION is designed to conserve wetlands. It was signed in 1971 in Iran and has been adopted by 168 countries. THE CONVENTION ON INTERNATIONAL TRADE IN ENDANGERED SPECIES (CITES) restricts trade in endangered species and their products across the globe. It has stopped legal international trade in products like ivory and tiger skins. It was signed in 1973 and has been adopted by 180 countries. THE WORLD HERITAGE CONVENTION designates and protects outstanding cultural and natural sites. It was signed in 1972 and adopted by over 180 countries. THE CONVENTION ON BIOLOGICAL DIVERSITY (CBD) entered into force on 29 December 1993. It has 3 main objectives: the conservation of biological diversity, the sustainable use of the components of biological diversity and the fair and equitable sharing of the benefits arising out of the utilisation of genetic resources. It has been signed by 193 countries

Measuring/assessing ecosytems

There are various ways of assessing threatened ecosystems. None gives a complete picture and they all produce differing results because they are all measuring different things. IUCN Red List of Endangered Species Compiled by the International Union for Conservation of Nature (IUCN). It is constantly updated and classifies organisms as critically endangered, endangered or vulnerable. It has identified over 16,000 plant and animal species in danger of extinction. Living Planet Index This was developed by the WWF in 1970. It monitors changes over time in the populations of animal groups such as amphibians, vertebrates etc. It looks at the relative health of forest, freshwater and marine ecosystems. Millenium Ecosystem Assessment (MEA) This was produced by the UN to assess the state of the world's biodiversity at the start of the 21st century. Research is ongoing.

Strategies to conserve ecosystems

There is a spectrum of conservation strategies available, from complete protection through various types of sustainable development, to commercially exploited areas where limited parts are protected for publicity purposes (TOKEN PROTECTION)

Nutrient cycling

This describes the movement of nutrients around an ecosystem, from the environment to organisms and back again to the environment. Nutrients are stored in three parts of the ecosystem: in the soil, in the living biomass and in surface litter. Plants take up nutrients from the soil and pass them on to herbivores who then supply carnivores. As plants lose their leaves, or living things die, nutrients are returned to the soil as they decay. If the cycle is broken the ecosystem may decline. This is an open cycle, as nutrients can be added or removed by processes such as rock weathering or LEACHING. People can have an impact on the cycle by adding nutrients via fertilisers, by reducing the biomass through overharvesting and deforestation, and by degrading the soil.

Total protection (SCIENTIFIC RESERVES)

This strategy was particularly popular during the 1960s, with areas completely fenced off from local people. Total protection strategies have been criticised for a number of reasons, although they are still used, and they do preserve habitats and wildlife. Some criticisms include: - In the poorest countries of the world, there is a conflict between conservation and cutting people off from biodiversity. - Totally protected reserves are often narrowly focused for scientific purposes, and there may be a failure to see that conservation is also influenced by social, economic, cultural and political factors. - Many protection schemes are based on political and administrative boundaries, whereas ecosystems are defined by natural borders. - Protection strategies often rely on coordination by outside agencies which are not always alert to the needs of the local people.

Factors threatening biodiversity (3)

Threats occur due to unsustainable population growth/densities and natural resource consumption. Key factors include: Inequality of ownership of resources Narrow range of agriculture, farming and fishing products demanded Failure of governments to value the environment and resources Legal and financial systems that promote unsustainable exploitation for short-term profit Lack of understanding of how to manage and conserve biodiversity.

TNC'S

Transnational Corporations and their decisions about business location, production methods and pollution levels influence ecosystems. They also drive innovation and technology change by the process of technology transfer, sometimes with positive effects but more usually to the detriment of ecosystems.

Trophic Levels (1)

Trophic Level 1 - Producers (Plants) Grass, leaf, phytoplankton Trophic Level 2 - Consumers (Herbivores) Worm, caterpillar, zooplankton Trophic Level 3 - Consumers (Carnivores) Blackbird, woodmouse, fish Trophic Level 4 - Consumers (Higher carnivores) Hawk, fox, humans

Assessing the yield

Two measures are used to assess this yield: MAXIMUM SUSTAINABLE YIELD (MSY) is the greatest harvest that can be taken indefinitely while leaving the ecosystem intact. Harvesting wild plants, animals or fish is part of the subsistence lifestyle of indigenous people and is usually sustainable. Overharvesting, or overexploitation tend to be the result of commercial rather than subsistence activity. When maximum sustainable yield is exceeded, the target species and their habitats become threatened. OPTIUM SUSTAINALE YIELD (OSY) is the best compromise achievable in the light of all the economic and social considerations. This level of yield, unlike the MSY, will not destroy the aesthetic or recreational value of the ecosystem and will therefore allow multiple use for the maximum benefit to the community.