Biology (6.6): Populations and sustainability

carrying capactiy

the maximum sustainable population for a species in a particular habitat

types of strategists

K and r strategists

K-strategists

organisms are more sensitive to abiotic factors and their populations increase slowly

What is the population size of K-strategists mostly determined by?

the carrying capacity (K)

r-strategists

organisms less sensitive to limiting factors and their population increases rapidly

What is the population size of r-strategists determined by

rate of reproduction (r)

Characteristics of K-strategists (8)

1. slow reproduction

2. slow development

3. late maturity

4. extended parental care

5. longer life

6. larger

7. secondary or tertiary colonisers

8. stable/favourable environments

Characteristics of r-strategists (8)

1. fast reproduction

2. fast development

3. early maturity

4. little/no parental care

5. shorter life spans

6. smaller

7. pioneer species

8. hostile/changeable environments

conservation

active and dynamic interventions by humans to maintain or improve biodiversity

preservation

attempting to keep habitats as they are, preventing change and eliminating human activit

reasons to conserve or preserve

1. economic

pollarding

preserves wood stocks and prevents grazing

coppicing

tree is cut close to ground level increases shoot growth at the base increasing yields

benefits of coppicing (4)

1. rapid new stem growth

2. varied light levels

3. variety of habitats

4. prevents soil erosion

Small scale timber management techniques (2)

1. coppicing

2. pollarding

Large scale timer management technique

FSC guidelines

Aims of the FSC guidelines

1. end clear felling

2. re-forestation

3. ecological functionality

4. benefit local

MSC

marine stewardship council

What are the MSC’s three principles

1. sustainability (fish maintain carrying capacity)

2. ecosystem impacts (not damage habitats)

3. good management (legal restrictions and adapting to change)

Legal restrictions for fishing made by the MSC (6)

1. annual quotas

2. mesh sizes

3. restrict certain species

4. boat sizes

5. sailing duration

6. monitoring & inspections

criticisms of MSC (4)

1. fishing zones too large to monitor so not enforced

2. monitoring expensive

3. false reporting of catch size

4. fish die when thrown back if over quota

Problems with aquaculture

higher risks of parasites, ugly, pollutes waterways

problems with consuming krill

passes problem to another trophic level and changes to eating habits are slow as people are resistant

Examples of how ecosystems can be managed to balance the conflict between conservation/preservation and human needs (3)

1. Masai Mara region of Kenya

2. Terai region of Nepal/India

3. peat bogs

wildlife conservancies

collaborations between many land owners around the Masai Mara and tourism companies where land owners receive incomes to promote conservation, de-fence

Human-wildlife conflicts in the Terai region of Nepal (6)

1. humans attacked by wildlife

2. cattle killed by wildlife

3. crop raids by wildlife

4. chemical fertiliser use

5. forest wood used as fuel

6. poverty driving poaching

How has local conservation in the Terai region of Nepal and India happened? (6)

1. local communities permitted to exploit forest whilst looking after it

2. seek to reduce human-wildlife conflicts

3. solar powered electric fences

4. wildlife migration corridors

5. anti-poaching patrols

6. biogas plants

How have they conserved the Masai Mara in Kenya? (3)

1. local population lead anti-poaching efforts

2. conservancies set up where locals manage the land so it benefits domesticated and wild organisms

3. managing tourism

Peatbogs

wetlands that contain partially decomposed biomass due to anaerobic conditions that are sites of high biodiversity (mosses and birds)

What does drying peat bogs do?

releases carbon dioxide and increases risks of flooding and fires

What does draining peat bogs with ditches and afforestation do?

dries landscape for other uses

Examples of environmentally sensitive locations that require limits over human activities (4)

1. The