Ecosystems at Risk

Question 1

How do biophysical interactions led to diverse ecosystems and their functioning

Answer 1

• Latitude/ climate - diverse
• Precipitation (hydrosphere/atmosphere) - diverse
• Nature of soils which provides habitats for decomposer organisms
• Food webs - functioning
• Cycles (carbon, nitrogen, phosphorus)

Question 2

How does climate/latitude led to diverse ecosystems

Answer 2

Different latitudes create different climates
Equator = humid, high temperature, high rainfall –> tropical rainforest
Poles = low temperature, low rainfall –> tundra ecosystems

Question 3

How do cycles/ food webs led to diverse ecosystems/ functioning

Answer 3

Nutrient cycling leads to ecosystem productivity controlling the flow of energy and biomass.
Plants absorb nitrogen from the soil, this nitrogen allows a plant to photosynthesis and to maintain structure. Nitrogen is transferred around an ecosystem through the food chain and decomposition. Consumers such as herbivores, take in the nitrogen from their food allowing them to form tissue. Decomposers break down dead organic material and return nitrogen back into the soil. Nitrogen cycle increases the biomass of the ecosystem

Question 4

What does elasticity mean

Answer 4

the rate of recovery of an ecosystem property following disturbance - how long it takes for an ecosystem to recover from a stress

Question 5

What does amplitude mean

Answer 5

the amount of stress an ecosystem experience/ can experience before it can no longer return

Question 6

What does malleability mean

Answer 6

the difference between the ecosystem’s final recovery level and its pre stress state - the greater the difference the less resilient the ecosystem is

Question 7

What is the criteria to determine vulnerability and resilience of an ecosystem

Answer 7

Biodiversity
Extent
Location
Linkage

Question 8

How does biodiversity impact vulnerability

Answer 8

greater Bodiversity = greater level/ opportunity to adapt or withstand change
monoculture = bad

Greater genetic diversity - greater chance that individuals will have characteristics that enable survival during stress events

Greater species diversity - greater more complex ecosystem (greater linkage), less impact if one species goes extinct
Ecosystems will keystone species have a higher vulnerability

Question 9

Examples of biodiversity - vulnerability

Answer 9

Seagrass has high levels of genetic diversity enabling grass fields to grow back to pre-disturbance strength faster after grazing

Genetic diversity
Potato from south America

Coral Reefs contain 1,5000 species of fish and 400 species of coral enabling it to be resilient to change

Over 9,000 species of plants in Feinboss
Over 3 million species in the Amazon
Agriculture ecosystems are monoculture

Question 10

How does extent impact vulnerability

Answer 10

Small extent = high vulnerability
Since fauna and flora confined to small areas, very suspectable to stress e.g. natural disasters
Changes speed which
amplitude

Question 11

Example of extent impact on vulnerability of ecosystem

Answer 11

Feinboss Cape town - size of 4 football fields and has the rarest flowering species in the world with 5000 species in all. However the size of the ecosystem makes it extremely vulnerable to change e.g. landslide, urbanization

Dodo birds were restricted to Mauricous island leading to its extinction when the island was colonised
Made worst by islandisation

Coral reefs have a large extent 350, 000km2 which enables space for animal migration to protect them from stress

Question 12

How does location impact vulnerability

Answer 12

Location of an ecosystem effects its functioning. A greater degree of familiarisation an organism has to a particular set of environmental conditions the more vulnerable an ecosystem is to change.
As well as proximity to humans

Question 13

Example of location impact on vulnerability

Answer 13

Coral reefs require: (very extreme climate)
- located above 50m so sun light can penetrate
- 27 degrees
- water must be clear, clean and salty
- water must be nutrient deficient because it increased nutrients result in increased algae and thus decrease sunlight

the change of even a few degree can cause coral bleaching
Coral reefs also close proximity to humans thus greater vulnerability to exploitation for agricultural, urban and industrial use e.g. trolling, anchoring, overfishing, impact of run off

Question 14

How does linkage impact vulnerability

Answer 14

The greater the level of interdependence within an ecosystem the greater the ability to absorb change - linked to species diversity

Question 15

Example of linking impact vulnerability

Answer 15

The artic krill are the main primary consumers in which the ecosystem’s wood chain would collapse if their population declined.

Question 16

What is a natural stress example

Answer 16

• Mt St Helens - natural catastrophic
  natural events of an earthquake and volcanic eruption resulting in lateral blast in molten rock, ash clouds, landslides
• Cyclones fires and droughts (not catastrophic)

Question 17

Stats of Mt St Helen impact

Answer 17

• all vegetation for 25km destroyed
• 500 sq km of coniferous forest blown away
• only 14 out of 42 animal species survived
• ash cloud reduced oxygen levels on land and in water
• 67000 animals died from eruption and lava flow
• 1 500 000 animals died from ash fall

Question 18

results of Mt St Helen eruption

Answer 18

• animals who survived the initial explosion died from a lack of food and clean water
• first animals to return were those with a wide food tolerance e.g. deer, mice, gophers
• oxygen deficient led to anaerobic organisms who don’t need oxygen to survive dominate water system
• disclimax and simplification of biodiversity
  weedy plants with a wide tolerance have invaded the are becoming common
• upper slopes between the new summit was still bare of vegetation, with a ‘Luner’ like surface

Question 19

Cyclones as a natural stress

Answer 19

• not catastrophic
• Cyclones on the GBR can destroy small sections of coral but also do not have a major impact on the functioning as it can provide relief from crown thorn starfish invasion and they are a on a small scale localised and shortlived, unlike human modifications

Question 20

What are the human modifications to ecosystems

Answer 20

IPODS
Islandisation
Pollution
Overharvesting
Habitat Destruction
Species Introduction

Question 21

Human modifications - islandisation(explain)

Answer 21

Cause: leaving undisturbed pockets of habitat in amongst surroundings of modified habitats
Effect: As large animals need large reserve, the margins of rainforests have lost species. Also problems with disease may arise leading to piecemeal destruction of the ecosystem
- decreasing extent of ecosystem

Question 22

Example of islandisation

Answer 22

Islandisation in the Amazon had impacted ant bird who follow ant colonies however due to psychologically evolved to stay in the dark and is unable to follow them out of the dense forests

Question 23

Human modification - pollution

Answer 23

Cause: Pollution of CO2, methane and nitrous oxide into the atmosphere by human activity e.g. combusion of fossil fuels
Effect: enhancing the greenhouse effect

Question 24

Example of pollution

Answer 24

Humans excess CO2 emissions
- seal levels are 10 - 20 cm, glaciers are -
- melting, more intense weather patterns (hurricanes, droughts, fires , floods)
- killed 60% of the krill population
- heavy impact on location dependent ecosystems e.g. coral reefs and pole regions
- coral bleaching

Question 25

Human modification - overharvesting

Answer 25

Humans clearing land and removing species at a faster rate than they are replenished for agriculture, food sources, fuel sources

Question 26

Stats on overharvesting

Answer 26

• humans overharvest trees 10 times faster than they replenish - 3 football fields from the amazon per minute
• 70% of marine species are being caught faster than they reproduce (trawl netting bi catch)
• up to half of the entire planets growth of plants and large growth of animal growth is harvested for humans yearly

Question 27

Example of destruction of habitats

Answer 27

Fein-boss environment (biological hot spot)
highest concentration of plant species in the world.
40% of the original area was destroyed by human activities such as agriculture and the spread of the city
Destruction of the habitat destroys things reliant on the habitat

Question 28

Human modifications - introduction of species

Answer 28

The introduction of a non native species
Threatens biodiversity of adapted organisms by introducing new predators

Question 29

Example of introduction of species

Answer 29

• Hedgehogs were introduced from Scotland as a garden pet in the 1970s however they wouldn’t only eat the similar prey as native species but also caused the collapse of the dung bird breeding as they fed on their eggs
• Initially giant west African snails were introduced to be eaten however they invaded and reduced food sources for the unique species native to Hawaii. In turn they introduced killer snails to kill the giant west African snails however the killer snails also ended up destroying native Hawaiian species to the extent of extinction(90% now extinct) - use to be about 750 native species

Question 30

How does the atmosphere impact the functioning of ecosystems

Answer 30

Atmosphere is the main source of the climatic factors
- temperature
- rainfall
- main source of nutrients- nitrogen, carbon, oxygen as well as water
- Sunlight

Question 31

How does the hydrosphere impact the functioning of ecosystems

Answer 31

• Water cycle
• large bodies of water moderate the temperature of close land

Question 32

How does the lithosphere affect the functioning of ecosystem

Answer 32

• determines the nature of soils which provide habitats for many decomposers organisms
• the recycling of the minerals essential
• the capacity of the soil to store nutrients
• differences in elevation

Question 33

How does the biosphere affect the functioning of Ecosystems

Answer 33

• biodiversity -greater biodiversity means more complex functioning and more resilient
• food chains - cycling of nutrients

Question 34

What are the nutrient cycles

Answer 34

• the carbon cycle
• nutrient cycle
• nitrogen cycle
• phosphorus cycle

Question 35

Why do be value ecosystems acronym

Answer 35

H - heritage Value
U - Utility value
G - genetic diversity
I - Intrinsic value
N - Need to allow progresses of selection, evolution and change to continue

Question 36

What are management strategies acronym

Answer 36

E - Exclusion
D- Design
E- Educate
A - Action
L - Legalization

Question 37

Acronym for evaluating the effectiveness of a management strategy

Answer 37

B - maintaining biodiversity
I - Intergenerational equity
P - Precautionary
I - Intragenerational equity