3.3 Threats to Biodiversity Flashcards
how many described species
1.8m, but scientists can only estimate how many other organisms remain undiscovered
why is the number of species poorly known
- some habitats are difficult to reach (i.e. the canopy of topical rainforests)
- lack of finance for scientific research
- difficulties with classification
- only a relatively small numbers of taxonomists globally are involved in identifying and describing new species
natural events that lead to the loss of biodiversity
- volcanic activity
- droughts
- floods
- ice ages
- meteor impacts
human actions that can lead to a loss of biodiversity (A HIPPO)
Agriculture
Habitat Loss
Invasive species
Pollution
Population (i.e. the effects of pop. growth)
Overhunting
what does the rate of biodiversity loss from country to country vary on
- the ecosystems present
- the protection policies and monitoring systems in place
- EVSs of the local residents
- the stage of economic development (i.e. LEDC or MEDC)
conflict between exploitation, sustainable development, and conservation in tropical biomes
most tropical biomes occur in less economically developed countries
- clearance of ecosystems provides land for cash-crops such as oil palm
- plantations provide financial income for local communities + employment
- clearance leads to biodiversity loss
- international legsilation
- willingness, dependent on social, economic and political views
can be resolved providing there is local support and the political will to protect biodiversity
factors that make species prone to extinction
- low reproductive potential
- small population size (lower genetic diversity)
- narrow geographical range
- seasonal migrants (long hazardous journey, reliant on multiple habitats)
- poor dispersers (cannot easily move to new habitats or non-flying animals)
- Specialised feeder or niche requirements
- a large body (10% rule means predators are rare, danger for humans, compete w humans for food)
- edible to humans + herding together (overhunted for food or for fun and can eradicate easily, especially if found in groups)
- island organisms (small populations, restricted genetic diversity human alterations of land through use of an already-limited habitat)
species based on factors that make them prone to extinction
- long migration routes (Siberian crane)
- human pressure from hunting, collecting, trade, etc (Sumatran Rhino)
- limited distribution (golden lion tamarin monkey)
- low reproductive potential (Bicknells thrush in canada only has 2000-5000 breeding pairs)
IUCN
The International Union of Conservation of Nature
what list did the IUCN create
the IUCN red lists
IUCN purpose
- highlight species threatened by extinction
- promote the conservation of species
- raise awareness + educate
- create a system that can be applied consistently
factors that are used to determine a species conservation status on the IUCN red list
- pop. size (smaller pop. are more likely to go extinct)
- reduction of pop. site
- degree of specialisation
- geographic range and degree of fragmentation
- distribution
- degree of endemicity
- quality of habitat
- trophic level
- probability of extinction
sliding scale IUCN red list
- Not Evaluated
- Data Deficient
- Least Concern
- Near Threatened
- Vulnerable
- Endangered
- Critically Endangered
- Extinct in the Wild
- Extinct.
species critically endangered
Sumatran Tiger: CRITICALLY ENDANGERED
- ecological role: top carnivore
- threats:
-> loss of habitat (tropical rainforest)
-> it is seen as a danger to humans and livestock so its hunted
-> fragmentation of habitat makes breeding difficult
-> poaching
-> species only found on Sumatra island
-> top predator = pop is small bc little energy reaches the top
method of restoring:
- strengthening law enforcement
- anti-poaching capacity
- jail time for poachers
- fines for poachers
species currently endangered but whos status has improved
GIANT PANDA
- eats bamboo, forest in china
pressures:
-previous habitat loss
- small isolated populations
- sepreate populations
-> increased vulnerability
-> loss of genetic diversity
method of restoring:
- china joined the convention of international trade in endangered species
-> makes trade for panda skills illegal
- many different concentration groups