Human Induced Change Research Paper

All ecosystems have the ability to withstand stress. They are able to resist being disturbed or altered and will restore themselves to their original condition if not disturbed too drastically. There are both natural and human induced stresses. An ecosystem is the dynamic complex interaction of plant, animal and microorganism communities and their non-living environment as a functional unit. Ecosystems include the biotic (living) and abiotic (non-living) elements of the environment and the relationships between the components. For the correct functioning of ecosystems it is imperative that the dynamic equilibrium (balanced change) is kept under control

A number of factors are relevant to how vulnerable ecosystems are to stress these include location, extent,
biodiversity and linkages. The location of an ecosystem affects it’s functioning greatly as the latitude can affect the climate and ultimately the nature of particular ecosystems as seen in the Daintree Rainforests which is located in tropical Queensland so therefore has a constantly wet and humid climate. The microclimatic features of a location can be significant enough to create a range of distinctive ecosystem types within relatively small areas; an example of a variable is the slope on which the ecosystem sits. When ecosystems are located in extreme environments such as desert or a polar region the flora and fauna needs to be highly specialised, meaning that smaller change has a greater impact on the ecosystem. The greater the specialisation of an organism the more vulnerable it is to change an example is coral. Corals are highly specialised organisms that flourish in relatively shallow, nutrient-deficient waters of the tropics and any increase in nutrients levels promotes the level of algae thus reducing sunlight available for coral growth. Global warming is drastically affecting coral reefs as the increase in temperatures is killing the corals. This is known as coral bleaching where only the white calcium carbonate skeleton survives, over 2/3 of the worlds coral reefs have already fallen victim to global warming.

The extent (size) of any particular ecosystem is the product of a variety of factors. Research has shown that the boundaries of ecosystems tend to overlap each other this can be seen in river ecosystems that extend beyond the river channel to include the whole drainage system, for example to Murray river and the Murray basin. Thus, human activity in the drainage basin can impact on the river itself even when it occurs some distance from the channel, it may increase soil erosion. Ecosystems are restricted to relatively small areas or have already been disturbed extensively and are especially vulnerable. Tropical rainforests, for example, have relatively small populations of a large number of species confined to a relatively small, confined area.

The biodiversity within in an ecosystem is vitally important for the correct functioning of the environment, biodiversity is usually considered at 3 levels: genetic diversity, species diversity and ecosystem diversity. Genetic diversity is the variety of genetic information contained in all the individual plants, animals and microorganisms. Genetic diversity occurs within and between populations of species as well as between species. Genetic diversity 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. A British study has shown that peach potato aphids that are resistant to common pesticides are less able to survive British winters than aphids not resistant to pesticides. Species diversity is a measure of the number of species at each trophic level of the ecosystem: if the population of one producer or consumer organism crashes there are other producers or consumers available that can fulfil a similar function in the ecosystem. If an ecosystem is diverse there is a range of pathways for the ecological processes to take place for example nutrient recycling. Many diverse ecosystems are characterised by highly specialised organisms. However a species may be vulnerable even if the ecosystem as a whole is not. Ecosystem diversity refers to the diversity present within ecosystems in terms of their habitat differences, biotic communities and the variety of ecological processes.

The interdependence, or linkages of an ecosystem are related specifically to species diversity. The greater the level of interdependence within an ecosystem the greater its ability to absorb change. The loss of a primary consumer from a food web, for example, its unlikely to have a major impact on secondary consumers if there is a range of alternative primary consumers on which to feed. For example there are few linkages up through Antarctica. Krill are the dominant primary consumer organism and the main source of energy (food) for some species of whale, and if there was any reduction in krill supply the number of whales will be directly impacted. Interdependence can also take very subtle forms for example, the flowering of plants can be fertilised by only one species of insect. This insect may, in turn, be dependant on some other organism for part of its life cycle. Some primary consumers have highly specific food sources, and many parasitic organisms depend on specific hosts such as the tick on humans. However, humans in the biological control of pest species can exploit the same characteristics. Large consumer animals may range across a number of small, localised ecosystems, having genetically adapted to the variations in all of them.

Resilience is the ability of an ecosystem to adapt to a changing environment and to restore function and structure following an episode of natural or human-induced stress. Ecosystems rich in biodiversity generally have greater resilience than those with little diversity. They are able to recover more readily from naturally induced stress (including drought and fire) and human-induced habitat destruction. The more successful a species is at regeneration and the adaptation the less vulnerable it is changes in its ecosystem. Long-term ecosystem degradation occurs when the magnitude and duration of the stress exceed the ability of the component to repair it. Natural sources of stress also play an important role in the functioning of ecosystems. Stress dependant organisms and processes rely on changes in their environment to produce or stimulate a growth of their systems. For example, some eucalypt species rely on fire to initiate a stage in their reproduction cycle. As with change, resilience is a natural part of ecosystem functioning.

Ecosystems are constantly changing and evolving in response to stress induced changes within the total environment.
These changes could be in response to changes in the availability of water, average temperature or many other natural events. Natural changes can be examined through two types of stress: immediate and gradual. Immediate natural stress is rapid and often irreversible for example a drought, fire or flood. The other stress is gradual and this is usually slow and unobservable, this can be seen in the gradual change of climate or the movement of a species. Human induced change has the ability to both change and destabilise dynamic equilibrium therefore putting humans use of resources before the protection of an ecosystem. Human induced change is also both immediate and gradual: immediate in terms of fast action such as deforestation, grazing and ploughing while gradual is often in terms of processes such as salinization and pollution. When these effects put ecosystems out of balance the dynamic equilibrium is changed and clear issues arise a drop in primary production and a decline in species vulnerability. These changes heavily affect ecosystems and their ability to successfully
function.

The ability to control and manage an ecosystems vulnerability and resilience is imperative in protecting and conserving ecosystems.