Conservation

Question 1

The evil quartet

Answer 1

1. Habitat destruction
2. Overhunting (overexploitation)
3. Introduced species
4. Chains of linked extinctions (trophic cascades)
5. Climate change
6. Extinction synergies

Question 2

Why care about conserving biodiversity?

Answer 2

1. Provisioning services (Food, water, raw materials, medicinal resources)
2. Regulating services (Air quality regulation, climate regulation, waste treatment)
3. Cultural services (Educational use, tourism and recreation, aesthetics)
4. Habitat services (Life cycles, migratory, genetic diversity maintenance)

Question 3

Preservation

Answer 3

• Removal of technology from natural areas, hands off wilderness
• Enjoy nature for intrinsic value - leave untouched

Question 4

Conservation

Answer 4

• Active management of the biosphere to ensure the survival of the maximum diversity of species and the maintenance of genetic variability within species
• Includes the maintenance of biosphere function
• Sustainable resource use

Question 5

Focus for modern conservation

Answer 5

1. Conserving endangered species
   * Demographic & genetic consequences of small population size
   * Population Viability Analyses & biology of small populations
   * Manipulative techniques that enhance survival probability and design of nature reserves for particular species.
   2.Conserving functional and structural aspects of important ecosystems
   * Diversity and stability of ecological communities
   * Habitat fragmentation
   * Landscape ecology
   * Island biogeography
   * Restoration ecology

Question 6

Minimum Viable Population

Answer 6

• MVP is the smallest population size at which a biological population can exist without facing extinction
  E.g. Great auk

Question 7

Population viability analysis (PVA)

Answer 7

• PVA is used to determine the probability that a population will go extinct within a number of years (i.e predict extinction rate)

Question 8

Habitat Loss

Answer 8

• Single greatest threat to biodiversity
• 50% of all species extinction have involved habitat loss
• Island biogeography theory predicts that around 50% of species are lost with 90% habitat loss

Question 9

Impacts of habitat loss: Habitat modification

Answer 9

• Degradation = process by which natural habitat is rendered incapable of supporting its native species
• Results in suboptimal habitat

Question 10

Habitat fragmentation

Answer 10

• Fragmentation is a problem because it:
  1. Reduces patch area
  2. Increases isolation among populations associated with fragments
  3. Creates ‘edges’ where unmodified habitat abuts matric habitat

Question 11

Habitat fragmentation: patch area

Answer 11

• Generally large contiguous patches better
• Fragmentation also increase distance between patches

Question 12

Habitat fragmentation: edge effects

Answer 12

• Impacts of fragmentation percolate into interior
• More pronounced in smaller patches
• Increase in aridity, wind, light, noise
• Change in microclimate: temperature and moisture

Question 13

Linking fragments: Corridors

Answer 13

POSITIVES
- Increase immigration
- Increase foraging area for wide-ranging spp
- Provide alternative refuge from large disturbance

NEGATIVES
- Increase immigration - spread disease, invasive species
- Facilitate spread of fire
- Increase exposure to hunters/ poachers

Question 14

Land sparing

Answer 14

• Land for agriculture and conservation are separated
• Human activities very intensive on ‘restricted’ area
  + high impact on ecosystem services in affected areas
  + Low impact on ecosystems in remaining area
• Spatial/ temporal spill over
• Not all ecosystems services can be ‘transported’

Question 15

Land sharing

Answer 15

• Food production integrated into native vegetation
• Based on synergies in ecosystem service provision
• Extensive land uses, requiring large areas
• Large land requirements no wildnerness