BIODIVERSITY
Environment
Biodiversity is the term popularized by the socio-biologist Edward Wilson to describe the combined diversity at all levels of biological organization.
Biodiversity is defined as 'the variability among living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part, this includes diversity within species, between species and of ecosystems'.
MEGA DIVERSE COUNTRIES
The megadiverse country is a term used to refer to the world's top biodiversity-rich countries. These were identified in 1988 by Conservation International, to promote the awareness for biodiversity conservation among world nations. There are 17 of these nations, which are mostly located in the tropical and subtropical region.
Criteria:
- At least 5,000 endemic plants.
- Must have marine ecosystems.
List: USA, Mexico, Brazil, Venezuela, Colombia, Ecuador, Peru, DRC, South Africa, Madagascar, India, China, Malaysia, Indonesia, Philippines, Papua New Guinea, Australia.
BIODIVERSITY HOTSPOTS
Hotspots: high endemism + high habitat loss.
India has 4 hotspots: Eastern Himalayas, Indo-Burma, Western Ghats, Sundaland (Nicobar Islands).
Criteria: 1500 endemic vascular plants + 70% habitat loss.
THREE LEVELS OF BIODIVERSITY
Genetic Diversity
Species Diversity
Ecosystem Diversity
FACTORS DETERMINING DIVERSITY
Habitat stress, geographical isolation, dominance, ecological niches, edge effect, geological history.
ENDEMIC SPECIES
Species found only in one region. Ex: Lion-tailed macaque.
KEYSTONE SPECIES
Species whose role is critical. Example: Tiger, starfish.
INDICATOR SPECIES
Species whose presence/absence signals environmental conditions. Example: Lichens.
FLAGSHIP SPECIES
Charismatic species used to promote conservation. Ex: Tiger.
PRIORITY SPECIES
WWF concept: Elephant, Tiger, Rhino, Ganges dolphin.
INVASIVE SPECIES
Alien species that damage native ecosystems. Example: African Catfish, Water Hyacinth.
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Subject: Environment
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