1. Biodiversity – the fine balance of an ecosystem
Design a Conservation Programme

2. Tristan albatross pair courtship preening, in habitat.
What is an ecosystem?
An ecosystem is an environment consisting of all the organisms (bacteria, plants, trees, insects, mammals, birds, fish, coral etc) and non-living components (air, water, sand, soil, rock, sunlight etc) in a particular area.
There are many different kinds and sizes of ecosystem, ranging from the ecosystem of a single rock pool or hedgerow, to the ecosystem of an entire forest, ocean, island or even a whole planet.
An ecosystem provides all the habitat, nutrients, food and water required for an organism’s survival.
Tristan albatross pair courtship preening, in habitat.

3. Ctenella chagius in coral reef habitat
What is biodiversity?
Biodiversity is the degree of variation of different life forms within an ecosystem.
Measuring diversity is used as a way to measure the health of an ecosystem. Greater biodiversity = Greater health!
There are different types of biodiversity:
Species diversity
Genetic diversity
Ecosystem diversity
Species diversity
It is important that there is diversity in the form of an abundance of species. There should be enough of a certain type of species that predators can feed without devastating the population of their prey.
It is also important that the ecosystem is species rich – that there are enough different types of organisms so that all members of the community can find a suitable food supply.
Genetic diversity
Genetic variation within groups of species is particularly important in order to adapt to environmental change. In order to survive, a species needs to be able to defend themselves from predators and competitors, access food, water and nutrients and find habitat. In the event of new predators, competitors, the introduction of new disease and the need to find new habitat, it is essential that an organism is able to adapt to those changes. Close genetic relations also lead to problems with reproduction – inbreeding can result in genetic conditions which impair the survival of their young.
Ecosystem diversity
Ecosystem diversity refers to the biodiversity of the ecosystem as a whole, including all organisms, ecological processes and physical setting i.e. aquatic environments, tundra, forest, rainforest, caves, ponds, deserts etc.
Ctenella chagius in coral reef habitat

4. All the different members of an ecosystem play an important role in maintaining it. If something happens to upset the balance, it can cause ripples across the whole ecosystem:
Loss of prey can lead to food shortages
Loss of predators can lead to overpopulation (meaning an increase in the number of pests and competition for food and habitat)
An over-abundance of predators can devastate the population of their prey
The introduction of new species can lead to competition for food, nutrients and habitat, and the spread of diseases
An abundance of species that are destructive to certain habitats can lead to habitat loss
Habitat loss can mean that more species succumb to bad weather, disease and predation, (which would in turn lead to loss of food supply for their predators)
Species that destroy habitat include: grazers such as goats, the crown of thorns starfish which destroys coral, and the jacaranda bug which devastated the St Helena gumwood by taking sap from the tree and encouraging the growth of a killer black mould.
Threats, endangerment and extinction of different organisms within an ecosystem can quickly lead to the endangerment and extinction of other members of the community.

5. What are ecosystem services?
Ecosystems are not just important to the organisms living in them, they are also important to us. Ecosystem services are the benefits (including economic benefits) that human beings get from natural ecosystems. The ecosystem must be finely balanced to ensure these services are provided. Ecosystem services include:
Services an ecosystem provides:
Clean drinking water
Medicines
Food e.g. wheat, fruit, meat, fish and spices
Materials e.g. cotton, silk, metal, wood, oil
Energy e.g. wind power, hydropower and biomass fuels
Services that provide culture:
Recreational benefits – different landscapes and water-based environments are used for walking, swimming and sports
Spiritual and cultural benefits i.e. a beautiful landscape can inspire happiness, art, poetry and a sense of cultural pride
Services an ecosystem regulates:
Pollination – to ensure the survival of crops
Carbon sequestration
Control of disease and pests (e.g. natural predators keep pest numbers low.)
Waste decomposition
Services an ecosystem supports:
Seed dispersal – essential for the continued reproduction of important plants
Maintaining cycles and the dispersal of nutrients e.g. carbon cycle, nitrogen cycle, water cycle and oxygen cycle
There are a number of economic benefits to maintaining a healthy ecosystem i.e. through tourism and ecotourism, and through the sale and export of products provided by the land e.g. food, livestock, pharmaceuticals, energy and materials.
There are many players involved in maintaining an ecosystem. There are those who directly provide services e.g. fruit trees, fish, water sources. There are also those who play an important role in ensuring that those providers survive and flourish e.g. animals that hunt pests that destroy crops, species that provide a food source, pollinators and species that provide or maintain essential habitat.
Carbon sequestration is where CO2 is taking up (e.g. by trees or peat bogs) and stored, thereby controlling the climate.

6. Human threats to conservation
People v Conservation
Human threats to conservation
The biggest threat to conservation is human activity e.g.
Deforestation
Coastal development
Pollution
Road building
Using natural resources
Over-exploitation
Introducing exotic species
The biggest threat to conservation is human activity. Examples include:
Deforestation: The removal of forest for agriculture, urban development, building roads and selling trees for timber . Deforestation can have a disastrous impact on the environment such as habitat loss, soil erosion and atmospheric pollution (which contributes to climate change). For example, the black cabbage tree can now only be found on high mountain peaks, on the island of St Helena, after it was cleared for farmland and used for timber and fuel.
Coastal development: Often associated with tourism (i.e. the building of airports, marinas, resorts and golf courses), coastal development has had significant impact on biodiversity, particularly in terms of destroying vital habitat for a number of species. Nesting sites for endangered marine turtles have been destroyed and disturbed by large numbers of tourists on the beaches. The mangrove forests and seagrass meadows ,which have been removed to create open beaches, play a vital role in trapping sediments which both stablise coastlines, protect coral reefs and provide homes for many varieties of fish. In some instances, tourist developments, such as piers and other structures have been built directly on top of coral reefs. Coral reefs are vitally important in supporting marine ecosystems. They provide essential shelter for many different sea creatures but also control the amount of carbon dioxide in the ocean, by turning carbon dioxide into a limestone shell. Without coral, the amount of carbon dioxide in the water would rise dramatically. Coral reefs are often referred to as ‘barrier reefs’ this is because they slow down the water from strong waves and currents, protecting the coast.
Pollution: Industrial waste, agricultural pesticides and human effluent are washed into lakes, rivers and seas changing the environment and killing many species of fish and other aquatic life, particularly coral. Pollution has also been linked to climate change which can lead to coral bleaching. A change in water temperature, or a rise in sea levels, can shock coral into expelling its symbiotic, algae which uses photosynthesis to generate nutrients. The result is that the coral is left weak and will often die.
Road building: Building infrastructure, such as roads and railways, involves the removal of trees and plants which provide homes and food sources for birds and insects. Traffic deaths have also particularly contributed to the decline in certain bird species, such as the barn owl.
Using natural resources: Drilling for natural resources such as natural gas or minerals can destroy ecosystems. There is current concern that the discovery of the world’s biggest deepwater gas find in a decade, in the Mediterranean, will damage the marine ecosystem above it, which hosts a variety of rare species of deep-sea sponges, molluscs and cold water corals.
Over exploitation: Over-harvesting for food, particularly fishing and hunting whales, has seriously depleted stocks. Food is not the only reason for this over exploitation of the seas. The pet trade has resulted in a huge demand for species such as the lined seahorse, the most popular aquarium fish in North America. The lined seahorse also has medicinal properties which have contributed to its decline. By-catch is also a big issue - many endangered species are accidentally caught by fisheries targeting other, less vulnerable, species.
Introducing exotic species: The introduction of new species can have serious effects on the native species within an ecosystem. For example, when the fruit tree Syzaium jambo, was introduced to Pitcairn to provide firewood, it rampaged across the island, threatening native flora such as the endemic plant Homalium taypau. The introduction of grazing animals, such as goats has also resulted in the destruction of native fauna which also impacts on birds and insects whose habitats have been lost.
On the island of St Helena, the endemic black cabbage tree is threatened by competition from the introduced New Zealand flax.

7. People v Conservation Conservation efforts Breeding programmes
Many volunteer organisations and government departments have tried to conserve and protect endangered species e.g.
Breeding programmes
Regulations and bans
Eradication of invasive species
Monitoring and tagging
Re-building habitat
Creating artificial reefs
Some successful conservation efforts have included:
Breeding programmes: Often taking place in captivity, at zoos and nature reserves, breeding programmes can prevent a species from becoming extinct and can result in the reintroduction of that species when its habitat has been rebuilt or when the threat to that species has been reduced. Examples of successful reintroductions, following captive breeding programmes, include the Arabian oryx and Przewalski's horse. However there are a number of challenges. Some species lose valuable ‘wild’ skills in captivity and therefore cannot survive when reintroduced. For example, reintroduced female golden lion tamarins often die in the wild as they do not have the essential climbing and foraging skills.
Regulations and bans: Procedures for regulating and banning activities such as fishing, hunting and drilling for minerals have been implemented by many governments to protect threatened species. For example many European governments have set a restriction on the amount of cod caught, to allow stocks to recover. However, regulations like this are sometimes ignored or not monitored effectively. Restrictions on international trade have also gone some way to protecting species such as the green turtle and its eggs.
Eradication of invasive species: Introduced species, such as rats and cats, which have threatened the survival of native species have often been targeted for eradication. This method can be successful e.g. feral cattle, rabbits and mice were successfully removed from Enderby Island in order to protect the endangered northern royal albatross. Unfortunately eradication is sometimes unsuccessful. Attempts to protect the Pitcairn reed-warbler from rats appeared successful until the number of rats recovered. Alien plants are also a problem, often outcompeting other native plants. Fieldworkers from the Tristan da Cunha Darwin Initiative Project have already undertaken measures to remove invasive New Zealand flax from the islands, in order to protect the native bentgrass.
Monitoring and tagging: Monitoring endangered and threatened species, using techniques such as tagging, beach counts and behavioural research, plays a key role in conservation. Surveying species to ascertain the state of breeding populations, a rise or decline in numbers and the most significant threats to a species helps us to ascertain when and how to take action.
Re-building habitat: In some instances habitat loss is so devastating that there have been efforts to rebuild the habitat i.e. through the planting of native plants and trees, or the reintroduction of wetlands such as mangroves. One way of recreating habitat for marine life is the deliberate sinking of shipwrecks (or old army tanks) to create an artificial reef. Shipwrecks provide perfect habitat with protection, surfaces and crevices for a number of different marine species. They are also a great opportunity for new coral and algae to grow. The hardiness of shipwrecks and, in particular, old war tanks also provides additional protection for the coral which are often devastated by storms.
The RSPB has announced plans to remove non-native rats from the Pacific Island of Henderson. The introduced rats eat an estimated 25,000 Henderson petrel chicks every year.

8. Striking a balance
Conservation is not always easy. Communities need to develop and grow. People need homes, food and employment. As the population grows – we need more land, more food and more industry. But, it does not always have to be a choice. Some conservation attempts have also generated revenue streams and new industry.
See the case studies provided in your student briefing packs to see the different ways conservation and economic growth can go hand in hand.
Look at the case studies:
What is the conservation? (What species is it conserving and how does it work?)
What is the economic benefit?