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- The variety of living things in a region
There are three kinds of biodiversity:
- Genetic Diversity
- The variation in genetic makeup within a population
- Species Diversity
- The number of species within an area
- Ecosystem (or Ecological) Diversity
- The number of different ecosystems in an area
Ecosystem services are the benefits provided by ecosystems that contribute to making human life both possible and worth living.
Biodiversity Loss Threatens Human Well-Being (see especially Box 1 near bottom of article)
- Food and fuel - especially important for subsidence farmers and fisherman. Biodiversity acts as a safety net.
- Provision of habitat
- Medicines and biochemicals - a majority of the medicines used are derived from plant, animals, or micro-organisms
- Recreational, educational, and spiritual values - for example, hiking, fishing, gardening, forest monasteries
- Climate control - size and shape of landscape over large areas affects the local climate
- Carbon sequestering - greater species biodiversity of plants increases the amount of carbon dioxide removed from the atmosphere
- Water quantity and quality - dense vegetation reduces erosion and improves water quality
- Protection against natural disasters - complex patches of vegetation reduce flooding and can give protection from winds and sea intrusion
- Soil fertility - fast-growing, nutrient-rich plants increase soil fertility; dense root systems prevent soil erosion. Greater species diversity increases soil organic matter.
- Pollination and seed dispersal - A large number of plants require insects and other animals for pollination and seed dispersal
Case Study: Artemesinin
Its source is the plant Artemesia annua.
Naturally derived medicines are an important ecosystem service.
Case Study: Honey Bees
An example of pollination as an ecosystem service is the honey bee. They are extremely important pollinators of crops.
However, honey bees are under serious threat from the disease colony collapse disorder:
Did you know?
Can you answer the following questions? Click on the link to find out.
How many species?
Number of species
- total described: 1.5 million
- total estimated: 5 - 30 million
- plants described: 300,000
- animals described: 1 million
Endangered species Those species which are at risk of extinction.
- extinction rates are currently as much as a 1000 times higher than historical rates
- scientists now state that we are in the sixth mass extinction event 
- 34,000 plants and 5200 animal species face extinction
- percentage of species facing extinction: bird 13%, mammals 22%, coral 33%, amphibians 41%
- 45% of Earth's original forests are gone
- biggest threats to endangered species are habitat loss and invasive species
The Red List and CITES
The International Union of Conservationists (IUCN) evaluates species to determine how endangered they are. These evaluations are collected into the IUCN Red List. Species are rated into Least Concerned (not endangered), Near Threatened (not currently endangered, but conditions are such they may), Vulnerable, Endangered, Critically Endangered, Extinct in Wild (only in zoos, etc.), and Extinct.
Important in endangered species is to prevent trading in wildlife. The main instrument for this is the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). This is a legal treaty which restricts or prevents trade in certain species. The list of species can be found here.
A serious problem is invasive species - plants and animals not native to an area and disrupt the ecosystem.
- The world's major communities classified according to the predominant vegetation 
The WWF has identified 14 biomes:
- Tropical and subtropical moist broadleaf forests - extremely diverse, may contain half of all species.
- Tropical and subtropical dry broadleaf forests - less common than rainforests; main biome in Thailand
- Tropical and subtropical coniferous forests
- Temperate broadleaf and mixed forests - large tracts lost to logging and other development
- Temperate coniferous forests - includes old growth forests, where trees are over 150 years old
- Boreal forests/taiga - mixed forests found Northern areas; together these store more carbon than the rainforests
- Tropical and subtropical savannas - grasslands, typified by the Serengeti grasslands
- Temperate grasslands - most native grasslands have been converted to farmland
- Flooded grasslands - important for many migratory birds, play important roles in flood control and water quality
- Montane grasslands - mountain ecosystems, often highly adapted and fragile
- Tundra - treeless polar climate with low vegetation, easily distrupted
- Mediterranean forests - hot dry summers, cool moist winters; found in only five regions of the world
- Deserts - dry (<25 rainfall cm per year), parts of the Atacama Desert have had no rain in the last 200 years. Many species especially adapted to conditions.
- Mangrove - a type of woodland found in saline coastal tropical waters, important for many aquatic animals, 20% have been lost in the last 30 years (50% in some areas)
There are also 13 freshwater biomes and 5 marine biomes
WWF further divides the Earth into 867 terrestrial and 450 freshwater ecoregions:
for a larger and more readable version go here
Case Study: Mangroves
Mangroves forests are a type of woodland found in saline coastal waters, mostly in the tropics. The 2010 World Mangrove Atlas shows a 20% loss since 1980. Shrimp farming accounts for about 25% of that.
Threats to Biodiversity
The major threats to biodiversity are:
1. Habitat loss
- Land use change due to:
- Roads and other infrastructures
- Residential, commercial, and industrial areas
- Pollution and climate change
2. Invasive species
- Excessive logging
- Illegal wildlife trade
In order to protect biodivesity we need to:
- Studying and identifying biodiversity, ecosystems, and endangered species (in order to know how to save it)
- Legal protection of endangered species (including CITES, CBD, national laws)
- Propagation of endangered species in captivity and their reintroduction to the wild
- Elimination or reduction of invasive species
- Establishment and management of protected areas
- Restoration of degraded areas (including but not restricted to reforestation)
When studying biodiversity sometimes we need to make priorities for what to study. One way is to use the concept of Hotspots.
Some areas have greater biodiversity than others. Tropical rain forests, mangroves, and coral reefs are examples with high biodiversity.
One of the best list of hotspots is Conservation International's Biodiversity Hotspots. They have identified 34 area which are both highly diverse and face serious threats. They have also identified 5 other areas with high biodiversity, but with fewer threats.
The most important of the methods for protecting biodiversity is protected areas, also called bioreserves.
IUCN classifies protected areas into categories. A description of these categories can be found HERE.
Protected Areas include:
- Strict Nature Reserves - IUCN Category Ia - (only human use is for scientific studying, monitoring, and education)
- National and Local Parks
- National Forests
- World Heritage Sites - includes both culturally and naturally important sites
- Biosphere Reserves (PDF) (under UNESCO)
- Ramsar Wetlands - Wetlands of International Importance (PDF)
- Protected Area with Sustainable Development (humans may live in area)
With current practices in agriculture:
- Wheat, rice, and corn account for more than half the food energy intake
- 30 crops account for 95% of food energy intake
- In last 100 years, 75% of agricultural genetic diversity has been lost
Plants and animals are bred to have different genetic traits. These traits either:
- Increase production (e.g. more milk)
- Increase resistant to disease
Little genetic diversity in an agricultural species can lead to susceptibility to a disease wiping out the entire crop.
An example of this happening is the Potato famine in Ireland.
Genetic diversity is also important for wildlife. High genetic diversity allows a species to adapt and survive. Low genetic diversity allows diseases to spread rapidly and causes problems with reproduction.
- Campbell, N.A. 1996. Biology, 4th Edition. The Benjamin/Cummings Publishing Company, Inc., Menlo Park, California