Vulnerability and Resilience of Ecosystems

Question 1

What causes vulnrability of an ecosystem?
(4 answers)

Answer 1

Biodiversity (genetics, species, ecosystems)
Extent (size)
Location
Linkages

Question 2

What are the three levels of biodiversity when looking at vulnrability?

Answer 2

Biodiversity is broken up into 3 levels, when looking at vulnerability:
Genetic diversity
Species diversity
Ecosystem diversity

Question 3

Outline genetic diversity

Answer 3

Genetic diversity refers to the variety of genetic information shared amongst all organisms within an ecosystem. It favours the survival of a species because it increases the chance that some members of the species will have characteristics that aid their survival if the population is subject to stress.

Question 4

Outline species diversity

Answer 4

Species Diversity measures the number of species at each trophic level in an ecosystem. The more diverse an ecosystem is, the more robust it is. For example, if the population of one producer or consumer crashes, there are others that can take its place and fulfil a similar function in the ecosystem.

Question 5

Define ecosystem diversity

Answer 5

Ecosystem diversity refers to the diversity present within ecosystems in terms of habitat differences, biotic communities and the variety of ecological process.

Question 6

What does extent mean?

Answer 6

Size

Question 7

The size of an ecosystem can result in the boundaries of different ecosystems overlapping. Give an example of this?

Answer 7

For example, if a river ecosystem extends beyond the river channel to include the entire drainage basin, human activity in the drainage basin can have an affect on the river ecosystem (e.g. increased soil erosion).

Question 8

Explain why a small ecosystem may be more vulnrable then a large ecosystem?

Answer 8

Smaller ecosystems are greattly impacted so the the small extent they cover, where are if a large ecosystem is impacted it is likely to imfluance one part of the ecosystem allowing for other to stay unharmed and encourages resiliance

Question 9

Also the size of the ecosystem can also refer to ecosystems that are restricted to relatively small areas, which are extremely vulnerable. Give an example

Answer 9

For example tropical rainforests have relatively small populations of a large number of species, confined to a relatively small community within the ecosystem. The loss of even a small section of rainforest, can, therefore be considered as risking the extinction of a variety of plant and animal species.

Question 10

On a global scale what factors play a decisive roles in determining climate and the nature of particular ecosystems?

Answer 10

At a global scale, latitude, distance from the sea and altitude all play decisive roles in determining climate and the nature of particular ecosystems.

Question 11

Some ecosystems are located in areas that are considered ‘extreme’. What are examples of this?

Answer 11

These include deserts, polar regions and high mountain peaks, hyper saline lagoons and areas of nutrient deficiency. Organisms that live in such conditions are considered to be highly specialised.

Question 12

Why could an ecosystem having a high degree of species specialisation be a concern?

Answer 12

The higher degree of species specialisation to a particular environment, the higher the vulnerability that species faces, if the environment changes.

Question 13

What impact does a growing population have on the ecosystem?

Answer 13

As a population grows, so does the demand for land. Ecosystems are encroached on, which causes urban development, dumping grounds, pollution and runoff into rivers/oceans, which ultimately destroys natural ecosystems.

Question 14

What does linkages mean in relation to an ecosystem?

Answer 14

The interdependance of an ecosystem

Question 15

What is interdependence related to?

Answer 15

Interdependence is related to species diversity

Question 16

Outline the positive impacts of high interdependence within an ecosystem. Give an example.

Answer 16

If there is a large amount of interdependence in an ecosystem, there is a greater potential to absorb change. Like species diversity, the loss of a primary consumer from a food web is unlikely to have a major effect on secondary consumers, if there is a range of alternate primary consumers on which to feed.

Question 17

Outline the negative impact of an ecosystem with low interdependence. Give one example.

Answer 17

Ecosystems that have a low level of interdependence have a higher level of vulnerability to change. For example in Antarctica, krill is the dominant primary consumer and the primary source of energy (food) for some species of whale. If there are no middle stages to this food chain and the population of krill is greatly diminished, the whale population in the ecosystem will be greatly affected.

Question 18

What organisims are more vulnrable to change disturbance/changes in the ecosystem?

Answer 18

Organisms that require ‘specific’ necessities are much more vulnerable to change disturbance/changes in the ecosystem.

Question 19

What are the two types of change that impact ecosystem?

Answer 19

Immediate and Gradual

Question 20

Give examples of an immediate natural change

Answer 20

Immediate – e.g. drought, flood, fire, volcanic eruptions, storm surge, cyclone.

Question 21

What negative effect can immediate natural change have on an ecosystem?

Answer 21

Immediate natural changes can have a dramatic effect on ecosystems, and in severe cases can wipe out the ecosystem in it’s entirety.

Question 22

Give examples of a gradual natural change

Answer 22

Gradual – e.g. natural fluctuations in climate, movement of species, adaptation to changes – natural selection.

Question 23

What negative effect can gradual natural change have on an ecosystem?

Answer 23

Gradual changes are likely to cause long-term changes to an ecosystem, such as changes to species found and numbers of species, functioning of the ecosystem.

Question 24

Outline human induced modifications to the ecosystem

Answer 24

Humans have the ability to simplify natural ecosystems in order to grow food, build habitats and remove or extract resources. Unwanted species are removed, and other species are provided with an environment made favourable for their survival by human intervention. Human-induced change can be intentional, inadvertent, or through negligence.

Question 25

What are the two types of human induced modifications?

Answer 25

Immediate and Gradual

Question 26

Give examples of immediate human induced modification

Answer 26

Immediate – deforestation, overgrazing, ploughing, erosion, pesticides, toxic substances, urbanisation, mining and war

Question 27

Give examples of gradual human induced modification

Answer 27

Gradual – salinisation and soil waterlogging, compaction and erosion, pollution, habitat loss, species loss, loss of biodiversity, introduction of exotics

Question 28

List some immediate natural changes to an ecosystem thay have a dramatic impact on organisms, populations and communities.

Answer 28

Cyclones, Floods, Volcanic eruptions, Bushfire. These types of natural changes can have drastic impacts on organisms, populations and communities.

Question 29

Outline the impact of cyclones

Answer 29

Cyclones will cause immediate damage to ecosystems. Trees and plants can be killed or damaged. Animals will flee or can be injured. The populations and communities of particular species will be reduced; however the ecosystem should recover relatively quickly.

Question 30

Outline the impact of floods

Answer 30

Ecosystems can recover quite quickly from floods. Plants and trees will be inundated, but should recover, depending on the length and severity of the flood. Some animals will drown, but many will flee.

Question 31

Outline the impact of bushfires

Answer 31

Bushfires have a drastic impact on ecosystems. All plants will be burnt some will be killed. However, many plants (particularly in Australia) will shoot new growth soon after the fire is out. Animals will flee as the bush fire begins. Populations and communities will suffer from a reduction in biodiversity (particularly animals) but will slowly return to the area as vegetation cover returns.

Question 32

Outline volcanic eruptions

Answer 32

Volcanoes have a drastic impact on ecosystems. All plants will be burnt and killed. Animals will flee previous to the eruption or die instantly. Populations and communities will be wiped out in the short-term but will slowly return to the area as vegetation cover returns.

Question 33

List two natural gradual changes to an ecosystem

Answer 33

Drought, Climate change

Question 34

Outline the gradual impact of drought

Answer 34

Droughts can have widespread and long term impacts on ecosystems. Plants will die due to lack of water, and animals will either starve or migrate to other areas. As a result populations of animals and plants will decline drastically. Communities will have a great decline in biodiversity.

Question 35

Outline the gradual impact of climate change

Answer 35

Human activity, particularly burning fossil fuels such as oil and coal, has contributed to an enhanced greenhouse effect that is warming the globe.
Climate change is impacting on weather patterns – rainfall, temperatures, natural hazards.
This will result in changes to vegetation patterns, ice coverage, ocean temperatures, local extinctions, changes to food chains and webs.

Question 36

CASE STUDY: Minnamurra Rainforest

Answer 36

Small rainforest located on the South Coast of NSW. Extent, biodiversity and location of the rainforest all work together to make this a vulnerable ecosystem.
Forest is located close to urban development and is surrounded by farms. This increases the level of pollutants entering the system and has led to significant weed infestation, particularly lantana which infests much of the forest
Minnamurra is a remnant forest of only about 160 hectares, meaning that it is a remaining small portion of what was once a much larger forest- less than 10% of the original forest remains. Significantly increases the vulnerability of the ecosystems because weeds, pests and diseases are more easily spread throughout the forest.
The biodiversity is threated by introduced species- such as lantana, that have invaded the forest.