Effects on the Earth’s Surface

BIOSPHERE
Plants:
Fire is a common occurrence in the Australian ecosystem and has been for many years. Many native flora species have learned to adapt not only to withstand fire but to benefit from it also. For example much of the Australian but more specifically South Australian, vegetation a consist of fire-adapted eucalyptus. Some other flora species, such as the Banksia. A plant which is commonly found in the Mount Lofty Ranges relies on fire in order to germinate and reproduced, as their seeds are unable to be released from their fruit until it is completely dried out or burned.

220px-Banksia_Marginata_Seedcoast-banksia-1

Images 1 & 2: The image on the top shows the dried fruit of the ‘Banksia Laricina’ plant. The fruit contains the seeds required for reproduction.  The image below shows a ‘Banksia Marginata’ plant photographed in Sandy Creek Reserve, Mount Lofty Ranges.

Bushfire can have a detrimental effect on the biosphere. It does not destroy the environment, but it may be an irreversible disturbance to some plant communities. If a fire occurs frequent and of high intensity it can lead to a limitation in the number of seed which are left to germinate and reproduce in the soil and therefore leaf the species closer to extinction.

Soil:
The fertility of soil can be drastically effected after bushfires to the extent that damage to the soil is dependent on the fire intensity and the condition the soil was originally in. Bushfires commonly burn and consume a large amount of organic matter which is located along the surface of the soil resulting in the efficiency of a number of key component such as nitrogen. Nitrogen is essential for plant growth as it allows plants to produce proteins and chlorophyll. Without nitrogen plant leaves will begin to turn yellow and their growth will be halted.

leaf

Image 3: The image on the right depicts the effects of nitrogen deficiency in soil on a corn leaf

Fire damage:
Fire damage to soil also increases the risk of erosion. When a fire moves slowly it generates a gas from the combustion of a plant when cooled it condenses into the soil. This creates a waxy later on the top of the soil which causes the soil to repel water. This phenomenon is known as ‘hydrophobicity’ and results in the dehydrated, barren soil. As the soil is so dry. As the soil is extremely dry the likelihood of erosion then increases

water puddle

Image 4: The photo above shows water pooling on top of the soil as a result of hydrophobicity.

Wildlife:
Animals are also affected by bushfires the effect can be seen in the population size and ecosystem these can be catastrophic. Wildlife which is unable to move quickly may be restricted to localised and specific habitats which can be severely affected by intense and rapidly moving fires. These animals may be killed by the fire itself or may die later from injuries such as burns, smoke inhalation and dehydration. A large decrease in population number can lead to a decrease in the reproduction rate which can have negative influence on the stability of the ecosystem in which the species belongs.

koala

Image 5: The image to the left is a well-known photo taken during the Black Saturday bushfires in Victoria, 2009.

Dehydration is a common cause of death amongst wildlife which are caught within a bushfire. The loss of flora and fauna from an ecosystem can upset the stability of that particular system which often makes it harder to re-establish. When trees and plants are damaged it not only effects that flora but also the fauna which depend on it to survive. Many small marsupials shelter and feed in the underbrush of shrubs whilst many birds and other animals for example koala depend on the trees for shelter and food. However, when animals lose their food and shelter it can be difficult for animals to find new, suitable habitats which can lead to further loss of life.

HYDROSPHERE
Waterways and catchment systems can also be negatively impacted by bushfire. The amount of damage caused is usually determined by the intensity and the size of the bushfire. As large-scale, high-intensity bushfires burn through vegetated areas they release harmful toxins and metals from within the soil and vegetation. If there was significant rainfall to occur soon after a fire dies away these toxins are eroded and washed into waterways such as rivers, streams, catchments, reservoirs and oceans. This is disadvantageous as the excess toxins in the waterways can have harmful effects on humans and agricultural consumptions. Exposure to the top soil from a loss of vegetation after a bushfire may also have negative effects on the hydrosphere. When the top soil is left exposed it can be subjected to being eroded into waterway via wind and/or rain. This increases the sedimentary build up in waterways and is likely to increase the siltation occurring. However, freshwater catchment system are able to regenerate a pre-fire condition within 5-25 years without any human interventions

catchment

Figure 3: The above cartoon depicts the possible post-fire changes to a water catchment system [5]

ATMOSPHERE
As bushfire can burn through a large amount of vegetation, ash and smoke are produced and released into the atmosphere. This combination is known to have negative affects to health and visibility. The smoke produced by the bushfire has been known to cause respiratory irritant. When inhaled the heat from the smoke can burn in your respiratory tract which can cause coughing, vomiting, nausea and confusion. If left untreated, smoke inhalation can lead to death as the carbon monoxide and cyanide in the smoke can act as a poison and can also induce pulmonary irritation and swelling.

Smoke and ash can also effect visibility as it is able to be transported throughout the atmosphere from tens to hundreds of kilometres depending on the force of the wind. Furthermore contact with harmful smoke can also lead to a rise in motor vehicle accidents as the visibility to motorist begins to decline.

https://www.youtube.com/watch?v=ioYGFIvNScg The video link above shows real life footage of the moment five CFS crew became trapped by a wall of flames while fighting the deadly Pinery fire Wednesday 25th November. You can see throughout the video that visibility is very low as a result of smoke and ash in the atmosphere.