3.3 threats to biodiversity Flashcards
humans impacting habitats
- land to urban, agricultural use
- fragmentation, transport routes
- degradation, over exploitation, pollution
estimating species numbers
host-specific species
- count the number of species in one area and extrapolate to a wider area
estimating species numbers
ratio of temperate and tropical species
- number of mammals and birds in the tropics is 2-3x higher than in temperate regions
- applying this ratio to other groups of species
estimating species numbers
taxonomic classification system
- group organisms by observed similarities
- each stage increased
estimating species numbers
data from taxonomy group experts
- collate data from experts
- UN global biodiversity assessment in 1995 did this
problems with counting number of species
- some counted more than once due to variation, not checking
- small groups of species hard to identify
- deep sea organisms difficult to access
- extinct before we are aware of their existence
- lack of taxonomy expertise to cover all groups of species
- lack of finances
- coordination required across the globe
over exploitation over resources
-renewable resources animals, fish, plants, need to be managed sustainably to ensure a continued supply
- need time to regenerate
habitat fragmentation, degradation loss
- technological developments, intensified farming, habitat loss
- increased demand for food, lack soil fertility, high soil erosion
- increase in mining, logging, water extraction
- fragmentation from roads, soil erosion and siltation of rivers from deforestation, contamination of ground and surface water, dust reducing air quality, noise disturbing species
ipcc climate change fact
2007, ipcc 30% plants and animals at risk of extinction due to climate change
iucn red list
- international union for conservation of nature
- inform status of species to catalyse action for conservation
- different criteria, least concern to extinct
criteria used to determine conservation status iucn red list
- population size, number of mature individuals
- population size reduction, loss of individuals over 3 generations
- geographical range, area of occupancy
- number of locations
- extent of habitat fragmentation
- quality of habitat
- probability of extinction
additional factors contributing to species vulnerability
- degree of specialisation, more specialized more vulnerable
- trophic level, higher up more pollutants
case study - extinct species
dodo
- endemic to mauritius
- dutch introduced new predators, hunting by humans, exploitation of resources destroying the habitat
case study - extinct species
tasmanian tiger
- competition from dingoes and dogs
- hunting by humans as it ate livestock, rewards for killing
- habitat loss, development of land
- population fragmentation, human induced fires
- disease in the 1920’s
case study - critically endangered species
hawksbill turtle
- tropical oceans and coral reefs
- sexual maturity between 20 - 40
- used in traditional medicine, shell in ceremonies
- tourist attraction
- coastal development, reduced nesting sites
- loss of feeding habitats, pollution of coral reefs
- ingesting plastic
- increasing temperature, unsuccessful incubation, beach erosion
- capture in fishing nets
- collecting eggs for flesh
