Unit 3 - AOS 1 - CH 4 - Threats & Managment strategies for biodiversity

Question 1

Habitat loss definition

Answer 1

“Reduction or destruction of natural habitats, ecosystems, or specific areas where organisms live and thrive (usually human activity)

Question 2

Describe contiguous and fragmented habitat

Answer 2

CONTIGUOUS: larger size of habitat
FRAGMENTED: habitat that has been split into smaller areas
- Smaller populations = more susceptible to changes in enviro

Question 2

Overexploitation definition

Answer 2

“The excessive or unsustainable use of natural resources, particularly living organisms such as plants and animals beyond their capacity to replenish or reproduce. “

Question 3

Inbreeding due to small population size

Answer 3

“Breeding between individuals that are close genetic relatives”

Inbreeding depression:
- “Decline in population fitness occurs due to increased homozygosity”.
- Due to relatives have ^ same alleles = ^ chance of deleterious recessive alleles being expressed
- e.g., genetic disorders, infertility, decreased, fitness.

Question 3

LOSS OF POLLINATORS, DISPERSAL AGENTS, HOST SPECIES OR SYMBIONTS.

Answer 3

Symbiotic relationships = “different species live together in intimate association, (May be critical for one or both organisms survival)”.

• Loss of interactions limit opportunities for mating, seed dispersal, colonization of new habitats or genetic exchange between population.

Question 3

Bioaccumulation, Biomagnification of pollutants

Answer 3

Bioaccumulation:
“The build-up of persistent, non-biodegradable pollutants within an organisms when it takes in more of the substance than can be removed”.
Biomagnification:
“The increasing concentration of a pollutant along a food chain through diff trophic levels

• Can cause physiological disorders, reproduction issues, reduced fitness and death. -> decrease in biodiversity and population size.
• Trophic cascade: Biomagnification

Question 4

Climate change

Answer 4

“Increasing global temps and extreme weather events”

• Alter temp & precipitation patterns = shifts in habitat ranges & fragmentation. = disrupts ecological interactions between species.
• Disrupt migration routes, breeding sites and food sources
  Can exacerbate existing threats to biodiversity and risk of extinction.

Question 5

Disease

Answer 5

Outbreaks = declines in pop size of susceptible species.
- Some species may be particularly vulnerable -> due to low genetic diversity, habitat loss or environmental stressors.

• Can be species specific (e.g. tasmanian devil facial tumour disease)

Question 6

Introduced species

Answer 6

“Species that have been deliberately or accidentally introduced into a new region”

• Can outcompete native species for resources such as food, habitat & nesting sites.
• Can lack natural predators or competitors in their new environment = rapid ^ in pop size.

Question 7

Conservation of biodiversity

Answer 7

“Range of strategies required to maintain & increase pop, build species resilience to environmental change”.

Question 8

Protected areas

Answer 8

“Nature reserves are areas of aquatic/terrestrial ecosystems that have been protected in order to conserve biodiversity”

• Most government owned = protected by law but some private.

Question 9

Benefits of protected areas as conservation

Answer 9

• Legal protection for endangered species
• Control of invasive species and human exploitation.
• Restoration of degraded habitat

Question 10

edge effect

Answer 10

“Described the boundaries between habitats or ecosystems”
- if area is fragmented = more edges = more areas of disurbance.

Question 11

Retaining remnant vegetation

Answer 11

“Fragmentation of habitat has resulted in small patches of remnant vegetation that need to be conserved and managed”

• Often small and isolated from other ecosystems.

Question 12

Wild life corridors

Answer 12

“Network of corridors cna be used to connect remnant vegetation”
- Involves habitat regeneration, restoration or replacement.

Question 13

Advantages and disadvantages of wildlife corridors

Answer 13

ADVANTAGES:
- Movement of animals between patches
- Providing habitat and avenues for possible recolonization
- Allowing for gene flow -> subpopulations to reduce impact of genetic drift & inbreeding.

DISADVANTAGES:
- Aiding spread -> diseases, weeds, pests
- Supressing genetic variation (genetic swamping) -> if genetic diversity of a subpopulation is swamped by that of the immigrants.
- Helps spread fire
- ^ cost

Question 14

Translocation

Answer 14

“Movement of individuals to an area where their # are low”
- When plants or animals are translocated to an area that their species no longer inhabits = reintroduced.

Question 15

Captive breeding & reintroduction programs.

Answer 15

• Re-introduced organisms may be collected from wild/plants grown in nursery/captive breeding programs.
  To be successful:
• Threats initially responsible for decline in species must be managed at site for translocation or reintroduction.

Question 16

In Situ conservation & adv/dis

Answer 16

“Focuses on restoration of ecosystems & protection of pop within their natural habitat”

ADVANTAGES:
- Species left in protected areas have access to natural resources & nesting sites.
- Able to protect more species at once & with larger population

DISADVANTAGES:
- Difficulty controlling illegal exploitation, especially in remote areas (humans take things etc. )
- Habitats may need extensive conservation & pop’s may continue to decline during habitat restoration.

Question 17

Ex-situ conservation

Answer 17

“Taking species out of natural environment to operate and restore habitat”
- Particularly useful when species is critically endangered.
- Conventional vehicles = zoos, botanical gardens
- e.g. captive breeding, seedbanks, gene banks.

Question 18

Gene banks

Answer 18

For collection of specimens & genetic material
- Material is often frozen -> preserve genetic diversity of species.

Question 19

Reduction and improved targeting of pesticides

Answer 19

Either reduce or improve targeting

• Pesticides -> travel high distances through enviro
• Improvements to agricultural crop management to reduce requirement for pesticide =- benefits for diversity of insect species.

Question 20

List the conservations for biodiversity

Answer 20

• Protected areas
• Retaining remnant vegetation
• Wildlife corridors
• Translocation
• Captive breeding & reintroduction
• In-Situ conservation
• Ex-Situ conservation
• Gene banks
• Reduction and improved targeting of pesticides.

Question 21

Habitat restoration

Answer 21

• Degraded ecosystems repaired via human intervention
• Goal = recreate previous ecosystem or create new ecosystem

Question 22

Erosion control

Answer 22

Erosion: wearing or rock & soil caused by moving water, wind or ice.

• Important when renewing/regenerating degraded areas.
• Control measures - planting vegetation along areas that are susceptible to erosion.

Question 23

Name the two ways to restore degraded ecosystems

Answer 23

• Habitat restoration
• Erosion control