4. Biodiversity declines in aquatic ecosystems

Question 1

Structure of the lecture

Answer 1

1. Evidence for biodiversity declines
2. Evidence for biodiversity increases
3. Controversies at the global vs., local scale
4. Drivers of biodiversity loss

Question 2

What are the 5 indicators for biodiversity declines in aquatic ecosystems?

1

Answer 2

1. Declines in marine fish diversity
2. Declines in freshwater fish diversity
3. Declines in coral fish diversity
4. Declines in marine cetaceans

Question 3

What are the 5 pieces of evidence that biodiversity might be fine in aquatic ecosystems?

2

Answer 3

1. Improved quality of bathing water
2. Improved freshwater invertebrates
3. Improved giant river otter
4. Improved whale populations
5. Rediscovery of ‘extinct’ spp.,

Question 4

What are the 3 main controversies around the health of aquatic ecosystems?

3

Answer 4

1. Global trends cannot be mapped to local trends without losing some of the nuance of the topic
2. Freshwater trends do not match marine trends
3. Misreported data (i.e., Van Klink et al., 2020)

Question 5

What are the drivers of change in aquatic ecosystems?

4

Answer 5

1. Increased global population size
2. Exploitation
3. Fishing down the food web
4. Invasive species
5. Agriculture
6. Habitat destruction via pollution
7. Sewage dumping
8. Climate change