Geography notes hsc: Ecosystems at risk: Ecosystems and the functioning

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Geography notes HSC:
Ecosystems at risk:
Ecosystems and the functioning

+Its important to understand the complexity of ecosystems before any management strategies can be instigated.
What is an ecosystem:
+An identifiable systems of interdependent organisms and non-living features of the environment.
+Are systems through which solar energy is transformed and transferred throughout a web of interdependent organisms.
+Ecosystems are dynamic and adaptable, ecosystems are constantly changing.
Variations in ecosystems:

+The components of any ecosystem can vary naturally or through human activity. Any modification will be magnified over time, and throughout the ecosystems, [small] changes in an ecosystem can be catastrophic.
Classifying ecosystems
+Ecosystems are classified according to their dominant feature. Hence they are named after: climatic types [polar, sub-tropical etc.], physical features [coral reefs, dune systems], and dominant vegetation [heath land, rainforest].
+the smaller the scale of an ecosystem the more likely it is named after a physical feature.
+Land based ecosystems: the greatest contributing factor to the type of ecosystem, is climate, [rainfall, temperatures etc.]

Marine based ecosystems: greatest contributing factor is the amount of dissolved nutrient in the water
The ecosphere:
+The ecosphere is a collection of living and dead organisms, interacting with one another and the non living environment. The ecosphere therefore represents the collection of all the worlds ecosystems:

ecosphere : biomes : major ecosystems [tundra etc] : medium ecosystems [sub-tropical rainforest] : small ecosystems [characterized my micro-climatic conditions].
Productivity of ecosystems:
+The productivity of an ecosystem is expressed in two ways:

-1- The mount of biomass per unit of area per unit of time

-2-The amount of energy that is contained in said ecosystem per unit area, per unit time.
+Energy flows through an ecosystems through each -trophic - level. Energy flows away from producers, to primary consumers, to secondary consumers, to tertiary consumers, along the way energy is recycled back to producers through decomposers and heat.
+Nutrient cycles are driven directly or indirectly by the sun, and include carbon, sulfur, water and oxygen cycles.
Factors affecting the functioning of an ecosystem:

+These are the four components of the biophysical environment.
+The atmosphere: The main source of climatic variation. Temperature, rainfall determine the nature of all ecosystems, an the speed at which they function. Also determines how pollutants are cycled through the world.
+The hydrosphere: The hydrosphere is closely linked with the atmosphere. The hydrosphere [in terms of rain] causes; land degradation, erosion and soil leaching. It is essential for high levels of bio-diversity. Large bodies of water moderate climatic conditions, and ensure less climatic variations in places were they adjoin land.
+The lithosphere: The lithosphere determines the nature of the soils, and provides habitat for many species. it also Stores mineral nutrients and water. The capacity for soils [and hence the lithosphere ] to perform these functions determines the nature of an ecosystems. For example sandy soils, drain easily and will hold little water for plants. changes in elevation create marked differences in climate, meaning similar soils can different ecosystems. Permafrost is an example of climatic differences due to latitude.
+The biosphere: Is the preside of all living things. autotrophic organisms like plants... eterotrophic like consumers...
+The technosphere: the built environment
Vulnerability and resilience of ecosystems:
+All ecosystems are in a state of dynamic equilibrium or a continual state of balanced change. This state of dynamic equilibrium is the product of the interrelationship of the elements of the ecosystem.
Causes of ecosystem vulnerability:
+location: latitude, altitude. extreme locations provide highly specialized ecosystems. The greater the degree of specialization the great the degree of vulnerability.
+Extent: The extreme of any ecosystem is due to : vertical-zonation, microclimatic features. Ecosystems that are restricted to small area are more vulnerable. Ecosystems such as rainforest, much diversity in small space mean more vulnerable. whereas savanna few species [little diversity] in big space mean less vulnerable.
+Biodiversity: 1 Genetic diversity [more means species ad ecosystem can adapt ;)

2 species diversity [more species means more resilience and there fore less vulnerability]

3 Ecosystems diversity [is the variety of habitats, process and communities]
Linkages: refers to the interdependence of organisms in an ecosystem. Ecosystem with more linkages are more robust. e.g. krill whale end versus plant ant or insect or bird or mammal end.
Natural and human induced stress:



Natural induced stress






+climatic change



+ecological succession


Human induced stress






+use of pesticides


+soil compaction


+land degradation

+introduced species

Human threats to bio-diversity include:
+species introduction

+habitat destruction


Case study: Mt St. Helens
+natural stress= earthquake, and volcanic eruption

-widespread damage and devastation

-few years natural recovery great coniferous plants growing etc.
Types of Human [induced] modification of the environment:

+humans have the ability to dramatically [and negatively] simplify the environment, in order to improve if for immediate human use.

modification include:

+removal: land clearing etc.
+replacement: replace destroyed ecosystems with simplified human one [mono-culture]
+Utilization: exploitation of native vegetation with some degree of damage e.g. forestry, pastoralism and recreation.
+Conservation: the positive maintenance and restoration of an ecosystem.
Nature of human induced modifications:
+Intentional ecosystem change: difficult to distinguish between the intentional and the unintentional. Some like are the unintended consequences of human activity. such as Abo. burning land, change vegetation patterns.
+Inadvertent ecosystem change: -inadvertent- damage caused by the expansion of the human built environment.

human activity

inadvertent affect


-reduction of biodiversity and the encouragement of excessive population growth of one species.

soil erosion

poisoning of the environment with pesticides etc.


total destruction of all ecosystems within the area that is built up.

poisoning f the environment in all adjacent ecosystems.

Ecosystem change caused through negligence:

+industrial disasters such as 2010 BP oil spill in the gulf of Mexico
Measuring the effects of human activity on ecosystem functioning:

+there is no standard measure of ecosystem degradation, only specialized statistics can be formed through survey.
The magnitude of change:

Refers to the extent to which an ecosystem has been stretched beyond its state of dynamic equilibrium. Measuring the data requires a benchmark and a survey of present conditions.
The rate of change:

+rate of ecosystem change is related to two factors:

1 rapid world population growth

2 the ever increasing demand for resources [a flow on effect of population increase].

+refers to the rate of species extinction, forest loss etc.
Human population and ecosystem change:

+an increase in human population will lead to a direct increase in the consumption of resources.
+impacts include: demand for land, more land clearing [more species loss and more erosion], lead to farming [loss of soil nutrients, poison the environment]

demand for minerals: land clearing, land loss, erosion, to mineral extraction, land poisoning.
The importance of ecosystem management and protection:

+reasons for managing and protecting include:
1 Maintaining genetic diversity:

+Ecosystems rich in genetic diversity are more resilient

+Genetic variations represent each species ‘survival’ strategy

+species diversity is important to preserve different types of organisms

+All of the above; genetic, species, ecosystem’s. are needed for a healthy environment hat can continue the process of “natural selection”.
there is no single argument for maintaining genetic diversity...a more pragmatic approach is needed, that recognizes that; resources, values [precautionary ethics], combine to argument’’
2 Utility value:

+is the value an ecosystem has in terms of exploitable wealth.

+utility value is broad; coal resources, to forests, to genetic diversity [for future genetic engineering]

terms: “existence value”: the price a community is prepared to pay [place on an ecosystem] to keep it in its natural state:

option value”: the cost of keeping the ecosystem in its natural state as opposed ti exploiting its resources.
3 Intrinsic value:

+the aesthetic of a ecosystem

+links between traditional owners of the land are always much stronger.
4 Heritage value:
natural features consisting of physical and biological formation or groups, which are of outstanding universal value from aesthetic or scientific viewpoint.”
5 The need to allow natural change to proceed:
the vast array of life on the planet, and the importance of the diversity of this life is essential to the continued adaptation and future of all organisms.
to ensure this preserves must be:

1 large

2 have natural not political boundaries

3 take into account the interests of locals

4 have a buffer zone

5 be well maintained and managed.
Evaluation of traditional and contemporary management strategies:
There is a growing acceptance that our present strategy to manage the ecosphere [and specific ecosystems] are not as effective as traditional management strategies.
The management of ecosystem:
There is no one measure of ecosystem health/management.

+there must be a benchmark to access present data against.

+Increasingly the environmental impact of human activity is being judged un terms of its ecological sustainability.

management approaches:

there are four key approaches to managing ecosystem:

1 preservation

2 conservation

3 Exploitation

4 Utilization
underpinning these approaches are five attitudes:

1 environmental imperialism [an extreme anthropocentric view]

2 utilitarianism [things only have value if they are used]

3 stewardship [people occupy the privileged position of being able to exploit, whilst having a responsibility to protect, foster and grow ecosystem]

4 Romanticism [a view that values the beauty of the environment].

5 Radical environmentalism [a view that holds to the extreme end of conservation. the view holds that any development is bad]
Evaluation criteria:
Contemporary approaches to the management of ecosystems focus on the extent to which the strategies adopted promote, or are consistent with the principles of ecologically sustainable development.
+Sustainable development is achieved by maximizing people economic and social well-being while maintaining the ecosystem and the biophysical environment.
the principle of sustainable development incorporates four concepts:

1 intrageneration equity: that the preservation of future needs doesn’t cost the “meeting”/satisfying of needs of the present

2 intergenerational equity: that the future generations have enough resources

3 the precautionary approach: in the face of uncertainty there should be no action of only the safest option.

4 biological diversity: there must be a distinction made between; species, genetic and ecosystems diversity. and each must be maintained independently, and in unison.
progress means: +that wars are avoided +food is provided +water is provided +education is provided +an acceptance of the intrinsic value of the ecosystem +the promotion of a sustainable lifestyle.
Minimizing human impacts in the ecosystem:
strategies include:



+action:-restoration and rehabilitation, replacement

+design: when maintaing an ecosystem it is important to minimize stress’

+legislation: to assist in the preservation
Changes in management strategies

The way ecosystems are being managed is constantly changing. It must be realized that ecosystem are not independent systems but are linked with many different ecosystems and cycles. A holistic view must be adopted that understands that any action may have many consequences.
Changing economic attitudes;

economists are understanding that ecosystems are fragile and very finite resources.

that if too much is removed an ecosystem will slowly die.
+an example if such government strategies include: carbon tax [?]
Changing technologies:
+new technologies have created an opportunity for less pollution, or less serve pollution. conversely the increase in technology has lead to an almost exponential output of pollution.
+possibility of new alternative technologies providing energy sources that do not destroy the environment so much and are renewable.
changing environmental attitudes:
+The attitudes towards the environment have changed as humans have watched the impacts of many of their actions on the environment.
+new politics

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