Topic 3.2 - Biodiversity

Direct threats to biodiversity

Overharvesting, poaching, and the illegal pet trade.

Indirect threats to biodiversity

Habitat loss, climate change, pollution, and invasive alien species.

Amplification of human impacts

When multiple impacts combine, such as climate change reducing resilience, their negative effects are amplified.

Alien species

A species that has been artificially brought into a new habitat.

Invasive species

An alien species that has no natural predators or competitors, undergoes a population boom, and harms the ecosystem.

Dutch Elm Disease cause

An invasive beetle that carries a fungus infecting elm trees as it burrows to eat.

Dutch Elm Disease management

Chopping down infected and surrounding healthy trees to remove the beetles' food source and prevent spread, genetically modifying elm trees to insert gene for resistance

Deliberate introduction examples

Species like rhododendrons, grey squirrels, signal crayfish, and rabbits in Australia.

Accidental introduction example

Brown rats introduced globally from Asia via trading ships.

Kakapo threat

An endangered New Zealand ground-nesting parrot whose chicks are easily killed by introduced rats, cats, and dogs.

IUCN Red List criteria

Population size, rate of increase/decrease, geographic range, breeding potential, and known threats.

-Does nothing by itself, but publicises endangered species for NGOs, governnments to act

Species extinct due to human activity

Passenger pigeon - used to be very populus in north america, numbers plummeted due to overhunting and destruction of habitat, went extinct

-Conservation efforts were unsuccessful

-Controlled seed populations through foraging, guano acted as fertiliser

Example of critically endangered species

Sumatran orangutan - only found in one island in indonesia, illegal hunting and capture for pet trade + habitat fracturing for logging and agriculture, only 14 000 in wild now

-Aesthetics, intrinsic value

Species which status was improved by conservation attempts

-Bald eagle, numbers dropped due to habitat hunting and pesticide use, banning of DDT, habitat protection and captive breeding programs led to bounce back

-Apex predator, keystone species that acts as top down controller

Perspectives of individuals governments and agencies towards conservation

Individuals: may be strong monetary incentive to poaching, may have no other choice..makes making the 'right' choice difficult.

Tragedy of the Commons

Overexploitation of shared natural resources due to the tension between individual self-interest and sustainable development.

Grand Banks cod collapse as Tragedy of Commons

Industrial fishing in the 1960s-1980s led to cod overharvesting and subsequent ecosystem and financial collapse by the 1990s.

Ocean plastic gyres

Large accumulations of floating macroplastics driven by ocean currents that slowly break down into microplastics.

-Ocean is single collective resource, individual selfish interest to dump waste in it.

Ecotourism in conservation

Adding financial value to the intrinsic value of an organism to provide job opportunities and support conservation programmes.