L6 - Tosh - Human Impacts on Biodiversity

Question 1

What are the 4 human enterprises that effect biodiversity?

Answer 1

Agriculture
Industry
Recreation
International commerce

Question 2

In what 3 ways do the 4 human enterprises effect biodiversity?

Answer 2

1. Land transformation
   - land clearing, deforestation, grazing, intensification
2. Global biogeochemistry
   - C, N, H2O, synthetic chemicals
3. Biotic additions and losses
   - hunting and fishing, invasion

Question 3

What trend is generally seen between human density and species richness? Why?

Answer 3

AS species richness increases so does human density.

This is because species rich areas have a high productivity. BUT increased human density increases the rate of habitat loss

Question 4

What is albedo?

Answer 4

the reflectiveness of a surface - in terms of the environment, it refers to how much energy is reflected back to space

Question 5

What effect does clearing forests have on albedo?

Answer 5

Albedo is reduced when forests are cleared as energy from the sun is trapped in clearings.

Question 6

What level of albedo do cities have?

Answer 6

Cities trap more heat than vegetation does.

• concrete 20% albedo
• tarmac 10% albedo

They also generate heat themselves. A cities microclimate can be 4% higher than the surrounding areas.

Question 7

Give 5 direct impacts of climate change to biodiversity

Answer 7

1. Changes in phenology/phenotype - may lead to species not working well together
2. changes in species distribution 0 arrival of non native species, potentially loss of species if their climate is altered
3. change in community composition
4. change in ecosystem function
5. loss of physical space - due to rising sea levels, increased storminess

Question 8

Climate change is moving too fast for plants, why might some plants be lost?

Answer 8

In the past trees have moved at a rate of 20-80km per century. Plants may not be able to keep up, and there are cities in the way

Question 9

How might climate change benefit plants?

Answer 9

The increased temperature may make soils more fertile. This would benefit the more aggressive plant species, causing a reduction in biodiversity

Question 10

Why might the moving of animals North be dangerous?

Answer 10

Animals may move north as to get to cooler temperatures - bats, dragonflies and butterflies already have.

It could be dangerous as some insects are vectors of animal and human disease - malaria mosquitos and swine fever

Question 11

What is predicted to happen due to climate change in the future?

Answer 11

1. greater frequency of extreme events - polar air mass vs. tropical air mass
2. rise in sea levels
3. expansion of deserts
4. increased temperature

55% of land will show a change in vegetation. Expansion of the boreal forest into present tundra. Dying of the tropics and forests will turn to shrublands

Question 12

State and describe the 3 ways humans are directly exploiting the earth

Answer 12

1. Bush meat
2. Fuel wood
   - 1/3 of current population depend on biomass fuel
   - demand greater than availably
   - an be offset by planting of trees
3. Marine Fisheries
   - increase in 50s and 60s, but decline post 80s
   - sea recovery can be slow
   - El Nino

Question 13

What is and what are the impacts of El Nino?

Answer 13

El Nino is a climatic event that occurs every 3-5 years. It changes the dryness and wetness of different areas.

An example: anchovies always drop in population at El Nino, but due to fishing too they dropped permanently

Wider impacts:

• flooding of S America
• drier conditions of central America, Columbia SE Asia, N Australia
• ## increased bush fires

Question 14

GIve 2 examples of how El Nino has effected the world in the past

Answer 14

1. The worlds largest fishery c(West cost of South America) collapsed due to over fishing during the 1972 EL Nino
2. French Revolution - was caused in part by the poor crop yields in 1788-9 in Europe resulting from an unusually strong El Nino effect between 1789-93