Lecture 6+7- Current Threats To Biodiversity

Question 1

What is a described species and how many exist globally

Answer 1

A described species is one we know to exist/ has been identified. There is 1.8 million globally

Question 2

What percentage of known birds, mammals and amphibians are at risk from extinction?

Answer 2

10-30%

Question 3

How much larger are current extinction rates compared to historical background rates?

Answer 3

> 1000x

Question 4

What are the two predominant drivers behind diversity loss?

Answer 4

1. Direct/proximate

2. indirect/underlying

Question 5

What are the five proximate drivers of diversity loss?

Answer 5

1. Habitat loss +fragmentation
2. Over exploitation
3. Invasive species
4. Pollution
5. Climate change

Question 6

What are the four indirect drivers of biodiversity loss?

Answer 6

1. Economic
2. Cultural
3. Political/ institutional
4. Demographic

Question 7

What is the relationship between proximate and indirect drivers?

Answer 7

Indirect drivers push proximal drivers

Question 8

Explain the link between fragment size and extinction

Answer 8

Large fragments are able to hold a greater number of individuals from a given species, reducing their risk of extinction. However, smaller fragments are less likely to be recognised by members of the same species after extinction events, increasing risk

Question 9

What were the impacts of human settling on Madagascar (give figures). What caused this?

Answer 9

Only 10% of endemic species remain, with 9.1% of total species being committed to extinction from 1950 to 2000.
These were caused by: timbre extraction, conservation for pasture razing +agriculture

Question 10

What regions are priorities for conservation efforts?

Answer 10

PATCHES

Question 11

Define an invasive species

Answer 11

Exotic species that outcompete/ eradicate native species

Question 12

What is an exotic species?

Answer 12

Any species living outside its natural range/ habitat

Question 13

What four features allow exotic species to become invasive?

Answer 13

1. High dispersal ability
2. High reproductive potential
3. Broad ecological niche
4. Lack of competition

Question 14

How do invasive species move? (Three ways)

Answer 14

1. Accidental introduction
2. Deliberate introduction
3. Natural expansion due to anthropogenic environmental change

Question 15

What are the impacts of non-toxic pollutions?

Answer 15

Distributed animal/ecosystem behaviour

Question 16

Give 6 examples of pollution

Answer 16

1. Toxic air (SO2) reduced lichen availability
2. River pollution and invertebrate fauna
3. Toxic DDT and Raports distribution
4. Bioaccumulation in food chains
5. Non-toxic microbeads
6. Light and noise pollution

Question 17

Give an example of the impacts of light and noise pollution

Answer 17

Altered turtle hatching and out to sea migration

Question 18

What are the impacts of climate on diversity?

Answer 18

Shifting species out of their optimal habitat conditions, where fitness is thus reduced.

Question 19

Define synergistic effects

Answer 19

Where the impact of two factors together is greater than the sum of their individual effects