Main Pressures/threats

Question 1

Current status

Answer 1

25% of all assessed species are threatened with extinction

Monitored vertebrate populations have lost on average 60% of population sizes

Over 75% of the worlds terrestrial surface shows significant impacts of people

The brink of the 6th mass extinction

Question 2

Mass extinction event

Answer 2

When species vanish much faster than they are replaced. This is usually defined as about 75% of the world’s species being lost in a ‘short’ amount of geological time - less than 2.8 million years

Question 3

What is a ‘threat’ to biodiversity?

Answer 3

Underlying driver/input –> source of threatening mechanism –>Threatening mechanism causing unfavorable state –> Unfavorable state of conservation target

Driver –> sources –> mechanism –> impact

Question 4

Examples of driver/source/mechanism/impact

Answer 4

1)
Driver: human population growth

Source: agricultural expansion

Mechanism: reduced habitat quality

Impact: reduced populations of elephants

2)
Driver: demand for smartphones

Source: lithium mine expansion

Mechanism: habitat loss

Impact: reduced populations of gorillas

Question 5

our impact on biodiversity

Answer 5

Not a question of number of people, BUT
- how we live
- how species respond

Question 6

Traits associated with sensitivity

Answer 6

• Specialized habitat and/or microhabitat requirements
• Environmental tolerances or thresholds (at any life stage) that are likely to be exceeded due to human changes
• Dependency on environmental triggers that are likely to be disrupted by human changes
• Dependency on interspecific interactions that are likely to be disrupted by human changes
• Rarity

Question 7

Traits associated with low adaptive capacity

Answer 7

• Poor intrinsic dispersal ability (species just being slow - a snail)
• Poor extrinsic dispersal ability (landscape comes in the way - a mountain)
• Low genetic diversity
• Low reproductive rates and outputs
• Evolutionary history
• Population size

Question 8

Overall patterns of threat impact

Answer 8

Amphibians are mostly impacted by logging, agriculture and hunting/over-exploitations

Birds are impacted mainly by over-exploitation/hunting, climate change, agriculture and logging

Mammals are mainly impacted by over-exploitation/hunting, logging, agriculture and invasive species

Question 9

Summary

Answer 9

We are on the brink of the 6th mass extinction

Threats are complex and can be viewed through the chain of: drivers, sources, mechanism and impacts

The higher level often determines ‘exposure’

But impact also depends on sensitivity and adaptability

Hunting and land use change are the major threats to vertebrates

But patterns vary across threats and taxa making much of the worlds a priority for something