Science Man and His Environment/Biodiversity

Definitions

 * Biodiversity : 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
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)



Examples

 * 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
The major drug used to treat malaria is Artemesinin.

Its source is the plant.

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.


 * Bees, Bees, Bees


 * Honey Bees


 * List of crop plants pollinated by bees

However, honey bees are under serious threat from the disease colony collapse disorder:


 * Colony Collapse Disorder

Did you know?
Can you answer the following questions? Click on the link to find out.


 * What is the fastest land animal? Answer video
 * What is the fastest animal? Answer
 * What is the slowest animal? Answer
 * What is the largest animal ever to have lived? Answer
 * What is the smallest vertebrate? Answer
 * What is the oldest living thing and how old is it? Answer

How many species?
Number of species


 * total described: 1.5 million


 * total estimated: 5 - 30 million


 * plants described: 300,000


 * animals described: 1 million

Threats to biodiversity

 * extinction rates are currently as much as a 1000 times higher than historical rates


 * 34,000 plants and 5200 animal species face extinction


 * 45% of Earth's original forests are gone

Invasive species
A serious problem is invasive species - plants and animals not native to an area and disrupt the ecosystem.


 * Cane toad
 * Cane toads in Australia


 * Zebra mussel
 * Zebra mussel


 * 100 of the World's Worst Invasive Alien Species

Endangered Species
Endangered species Those species which are at risk of extinction.

There is an international list of species called the Red List which is maintained by the International Union of Conservationists (IUCN). The list rates the species from least concerned to critically endangered.

Also maintained is the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). This is a legal treaty - it restricts or prevents trade in certain species. The list of species can be found here.

Biomes

 * Biomes : The world's major communities classified according to the predominant vegetation

WWF Classification
The WWF has identified 14 biomes:


 * Tropical and subtropical moist broadleaf forests
 * Tropical and subtropical dry broadleaf forests
 * Tropical and subtropical coniferous forests
 * Temperate broadleaf and mixed forests
 * Temperate coniferous forests
 * Boreal forests/taiga
 * Tropical and subtropical savannas
 * Temperate grasslands
 * Flooded grasslands
 * Montane grasslands
 * Tundra
 * Mediterranean forests
 * Deserts
 * Mangrove

There are also 13 freshwater biomes and 5 marine biomes

WWF further divides the Earth into 867 terrestrial and 450 freshwater ecoregions:

Terrestrial Marine Freshwater



for a larger and more readable version go here

Biodiversity Hotspots
Some areas have greater biodiversity than others. Tropical rain forests, mangroves, and coral reefs are examples with high biodiversity.

This leads to the concept of Hotspots. One of the best lists 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.


 * Map of the biodiversity hotspots.

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.

Report on declining mangrove forests

Reserve areas
Key to saving biodiversity is bioreserves

In addition to national parks, etc. there are a number of international recognized reserves:
 * World Heritage Sites - includes both culturally and naturally important sites
 * Biosphere Reserves (PDF) (under UNESCO)
 * Ramsar - Wetlands of International Importance (PDF)

Agriculture
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.

Wildlife
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.