Human impact on this ecosystem is generally good. We use
the savannas of Australia for agriculture and ranching (Hurst 16441). Beef and
wool are produced here with the use of the pastoral land (Burrows 503). The
ecosystem is affected by the process of this production. Fires that occur here
are often created by humans to “reduce the bulk of nutritionally poor herbage,
and to stimulate the growth of higher protein grass shoots” (Holt 430).
Although much of this bioregion is used as pastures, the burning and grazing of
the lands don’t seem to have a great negative effect on this area. Studies have
shown a strong correlation between grazing in this bioregion and the increase
of plant and invertebrate species (Ludwig). The constant grazing of the lands
prevents species from dominating the area. The change of the landscape promotes
diversity in species that grow and live there. Fires aren’t inherently
threatening to this ecosystem because it is essential to its existence. Fires
are a natural occurrence in savannas and other grasslands. Without fire, or the
suppression of fire, would allow scrubs and trees to grow and take over the
area, turning the savanna into a scrubland. The vegetation that survives and
populate the Australian savannas are adapted to fire. Grasses here are burned
by fire but their roots survive underground. The fast growth rate of grasses keeps
vegetation in the area at a healthy level, enough to sustain our use of the
ecoregion as pastures. The soils of Australian savannas are generally poor in
nutrients; however, fire is used to help the weak soil fuel the life of this
ecosystem. By burning the biomass in the area, we are speeding up the process
of the nutrient cycle. Nutrients are in the vegetation and are released by the
burning of the vegetation. They nutrients then decompose in the soil, allowing
rich vegetation to regrow in that area (Holt 430).
Grazing and fires have a great influence on the species which inhabit the area “As habitat heterogeneity shifted with the imposition of grazing on typical fire pattern, so too did the relative abundance of some species, and to the detriment or advantage of species tolerant or vulnerable to the shifting habitat states” (Kutt 104). So the species adaptation to fires dictate what will succeed the area. The variation of vertebrate species changes in the savannas, but this is not necessarily a bad thing because although species which aren’t well adapted to fire become less abundant in the area, other species which are adapted to fire will still grow and live there. One type of species is succeeding the less adaptive ones so there is still a healthy diversity of life in the savannas.
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| Fire history 1997-2003 [source:savanna.org] |