3.2.3 - biodiversity under threat

What is biodiversity

The variety of organisms living in a given area including different species, habitats and ecosystems

Approximately how much of the worlds plants and animals live in a TRF

50%

What is meant by species richness

The total number of different species in a given area

What is meant by species evenness

How evenly spread the population is across the species in a given area

Give an example of species evenness

F there’s 4 species there 25% of each in a given area

Give an overview of Escobars hippos

• early 1980’s he brought over 4 hippos to Columbia

• In 2021 there was over 100 (exponential problem)

• They broke free from the zoo and left to go free after his death

• Out perform local species as there aren’t any limiting factors

• Illegal to hunt them - difficult to manage

What are Escobar hippos and example of

Invasive species

How can there be a threat to an ecosystem

Directly or indirectly

What is a direct action

Actions that explicitly damage the biodiversity of an area

What is an indirect action

Actions that are not intended to damage the biodiversity of an area

Are Escobars hippos a direct or indirect problem

Direct

What is the definition of invasive species

A non-native organism that spreads into a new environment

Give another example of an invasive species

The kudzu vine

The kudzu vine

• plant from japan taken to southern USA

• Can get as high as 100ft

• Due to the hot climate in the USA it doesn’t die

• “The plant that ate the south“

• No predators of it in the USA

Why does the kudzu vine survive so well in the USA

• no cold season in winter to kill it

• No predators

What are limiting factors

Factors that help to regulate the growth of a species e.g. the cold helps regulate hippos but it doesn’t get cold in Columbia

Is the threat of invasive species direct or indirect

Can be either and tends to be a local threat

What is deforestation

The removal of trees for hinges such as logging or settlements

How many acres of rainforest are cleared every second

1 and ½

Deforestation

• reproduction of ring tailed lemurs has halved due to loss of habitat

• Areas are deforested for monoculture

• Baobab trees at risk of extinction due to bark extraction and clearing for monoculture

• 1/3 of all 8 million species are at risk due to human activities

• LICs prioritise economic benefit over environmental provision

What fractions of all species are at risk of extinction

1/3

What is monoculture

Only growing one crop as it provides a lot of economic benefits

What is overexploitation

When humans become too heavily reliant on one substance and use it too much until it as other negative effects

Overexploitation

• humans can cause it directly through overfishing, forestry or mining

• Can be indirect due to increased demand for consumption

• Forestry can have short term benefits but can lead to deforestation, loss of carbon sink and habitats

• Can also lead to desertification and may force people to migrate

• Health risks due to environmental issues of using fossil fuels

Climate change

• can easily lead to global sea level rise or melting glaciers

• May be 4-6 metres more water in the oceans worldwide

• Loss of habitats and animals living underwater e.g. coral reefs dying

• 4 degrees Celsius temp rise could lead to major extinction e.g. polar bears

How many degrees would sea temps rise to cause coral reefs to die

2 degrees Celsius

Which of the 4 threats has the most affect on biodiversity

Overexploitation as an example of it is deforestation which happens globally and can lead to global climate change.

How much did the population of vertebrates fall by between 1970 and 2010

52%

How much did the biodiversity in the tropics fall by between 1970 and 2010

56%

How much did marine species decline by between 1970 and 2010

39%

How does economic factors affect biodiversity

It may lead to poverty in LIC’s which could lead to lack of education so they don’t know about climate change and don’t know he effects deforestation could have, they also don’t have any other way to make money so they over exploit this

How does demographic changes affect biodiversity

Due to the 3% increase in population there is higher demand for food and resources which could lead to overexploitation of key ecosystems

Which ecosystems are most at threat from the millennium ecosystem assessment

• coastal areas

• In land waters

Which ecosystem developed into more of a threat really quickly

Mediterranean scored 10 in last century and 20 in this century - score has doubled

Which threats were the worse according to the millennium ecosystem assessment

• pollution increase the most - 29

• Climate change went from the least serious to second most serious now scoring 45 from 19

When was the millennium ecosystem assessment done

2001-2005