The influence of disturbance

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The influence of disturbance

Disturbance

introduces heterogeneity into the landscape. It brings about changes in ecosystem balance, which in turn alters the flows of elements across the landscape.
varies in magnitude, intensity, severity, frequency, predictability, and spatial association. Human disturbance can resemble natural disturbance but it varies from natural disturbance in terms of severity, timing and magnitude.
can alter the scale of spatial pattern and process. Human and natural processes tend to operate on different scales, resulting in different disturbance patterns.
can be caused through the absence of an event as well as events taking place eg - absence of fire in Eucalypt forests in Australia that require fire for regeneration.

Natural land cover patterns are the result of complex interactions between climate, terrain, soil, water availability and biota. Humans alter land cover patterns through urbanisation, agriculture and forestry. They remove part of the natural vegetation and replace it with managed systems of different structure.

The result of these disturbances is a landscape that is a mix of natural and human managed patches of different sizes and shapes (Krummel et al., 1987).

The most sensitive indicator of disturbance or landscape change is the local biota, so it is usually used as a way of quantifying change.

Some species are dependent on natural disturbance taking place so their richness and abundance is a function of the form and history of disturbance (like seagulls, and a number of weed species).

Susceptibility to disturbance is also often affected as a result of changed structure and composition of the landscape.

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