Thursday, 13 December 2012

Management of Ecosystems With Fire

   Controlled fires are very often used as a way to maintain the complexity, and therefore plant biodiversity, of a number of managed areas, such as grassland and forests. Appropriate burning practices can be extremely significant in preventing full succession to low diversity tree systems, and maintaining high numbers of habitats, along with other methods (see checklists created for this purpose by Lindenmayer, Franklin and Fischer, 2006). Menke, 1992, noted how prescribed burning can reduce alien annual plant seed production, increase diversity of smaller plants as competition for resources is removed, and increase long-term native seed establishment. It could be thought that this would result in increasing number of habitats for small animals such as insects (as long as the burning is controlled).
Prescribed burning of grassland to increase fertility, and decrease
competition for establishing plant species; source.
   However, I wanted to highlight a paper that is set to be published in February 2013 by Little, Hockey and Jansen, who looked at the impact of controlled burning on South African grassland bird and arthropod (such as insects) diversity. By studying eight sights of varying fire frequency over two summer seasons found that both of these assemblages reflected the immediate habitat disturbance of the fires in changing ways (depending on season and management practices). Fires particularly affected grassland-breeding birds, as areas were burnt in the territory-forming stage of the breeding cycle. Of 10 arthropod orders investigated in the area, only one responded positively to burning (that containing grasshoppers). Coleman and Rieske, 2006, also found arthropod abundance in oak-pine forests was devastated by burning, and took at least two growing seasons to begin recovery.

    I think studies such as this show that while controlled burning is becoming a popular method of reducing low diversity tree systems, and reestablishing native and rarer plant species, it can have dramatic affects on animal systems, even causing huge drops in abundances. This shows that it is necessary to investigate the effects of burning in particular areas before this is used to maintain ecosystems.
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4 comments:

  1. Unknown20 December 2012 at 13:51

    Hi Harrie,

    Nice blog! I am doing a blog on Pleistocene megafauna extinctions and I often read literature that tells me man-made burning of vegetation is often destructive to habitats. Your post has alerted me to the idea of managing ecosystems using controlled fire and I find this very interesting!

    Are there examples of nature reserves, etc. that have been managed using controlled burning, and who usually administers the fires?

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  2. Harrie D20 December 2012 at 14:38

    Hi :)

    Yes controlled burning can disturb many species' habitats, and is planned for the winter months to prevent disrupting breeding season. Fire management is usually administered and controlled by teams of caretakers and area managers, who also have fire-teams nearby to prevent disaster.
    Heathland is commonly maintained using burning techniques, for example the heath on the Isle of Man - a Code of Practice for that area can be viewed at: http://www.gov.im/lib/docs/daff/Forestry_column/heathburningcodebookletjune2010.pdf

    Harriet

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  3. Unknown5 January 2013 at 14:39

    Hi Harrie

    Looking at the positives and negatives. Do you personally believe that management by fire is a good thing or not? Burning habitats will always have negative implications, but do you think that positives far out weight these?

    Thanks

    Josh

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    Replies
    1. Harrie D5 January 2013 at 15:15

      Hi Josh,
      I think management with fire can be a good thing; it is particularly used on heathland, as the heath species that dominate the areas are difficult to remove and fire is extremely effective in holding these back and providing more habitats.
      However, as with all maintenance techniques, burning needs to be highly controlled and is definitely not always a good thing - I think in cases such as the above the positives outweigh the negatives. However in many other areas, particularly those with endangered species, burning can be a much more negative thing. In these cases it is much more likely that techniques such as grazing will be utilised.

      Harriet

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