Transcript Classroom presentation

Biodiversity – the fine balance of
an ecosystem
Design a Conservation Programme
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.
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
Ctenella chagius in coral reef habitat
– Ecosystem diversity
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)
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:
Services that provide culture:
• 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
• 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:
Services an ecosystem supports:
Pollination – to ensure the survival of crops
Carbon sequestration
Control of disease and pests (e.g. natural predators
keep pest numbers low.)
Waste decomposition
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
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
On the island of St Helena, the endemic black cabbage
tree is threatened by competition from the introduced New
Zealand flax.
People v Conservation
Conservation efforts
Many volunteer organisations and
government departments have tried to
conserve and protect endangered
species e.g.
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.
•Breeding programmes
•Regulations and bans
•Eradication of invasive species
•Monitoring and tagging
•Re-building habitat
•Creating artificial reefs
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?