Remembering the Invisible Species in Management

Rainer Rehwinkel, Southern Tableland Grassy Ecosystems Project, NSW National Parks & Wildlife Service


Article taken from Woodland Wanderings Issue 1

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SpiderBirds and flora of the grassy woodlands have received a high profile due to recent research and conservation efforts. It is important when making management recommendations based on this research that the other less conspicuous grassland fauna such as reptiles and invertebrates are also considered.

Management for one species may actually conflict with management for another species. In management of threatened species in grassy sites in the Southern Tablelands, we have been faced with just such dilemmas of conflicting management needs.

For example:

  • Shrubs planted to enhance a site for woodland birds may be a problem for its reptiles and invertebrates, as well as the other flora that depends on an open grassy ground layer. There will be a temptation to exclude fire, grazing, slashing or other methods of biomass control while the shrubs are establishing, but these may be essential for other grassland plants and animals.
  • Managing an isolated site by burning a large proportion of the site will kill individual reptiles and invertebrates and may cause local extinctions. On the other hand, not controlling biomass (grass buildup) can also cause problems. Patch burning, in which small areas of the site are burnt in a mosaic is probably best if burning is to be used.
  • Allowing regrowth of trees in a site that currently has few trees may reduce the site's attractiveness as habitat for specialised grassland reptiles.
  • At one site fenced off to stop grazing because of a salinity problem, kangaroo grass is starting to take over from the wallaby grasses which are used as food plants by caterpillars of the endangered Golden Sun Moth.

A general rule of grassy ecosystem management is that if a certain management regime has been applied for a long time, and this management has meant the retention of a range of species (both fauna and flora) at a site, then this management should be continued at least until better information is available.

Examining species

Designing management regimes to accommodate different threatened species may mean one or more of the following:

  1. Reduce the area proposed to be burnt/slashed/grazed to small patches, rather than large areas or the entire site.
  2. Aim to retain the site's structural diversity, not just the species that are present
  3. Plant shrubs only in areas where this will not reduce habitat for reptiles and invertebrates.
  4. Allow tree recruitment only over parts of a site to allow for structural and floristic diversity and habitat diversity for reptiles and invertebrates.
  5. Fence off only areas directly affected by salinity, not the entire site (although, remember that salinity has the habit of spreading over time!), so that biomass control and reduction of competition by controlled grazing can continue.
  6. For sites with a history of grazing, reduce grazing to times or periods that allow more sensitivity to the retention of a range of species, rather than eliminating grazing altogether.

If a threatened species is likely to occur on the site consult a Threatened Species Officer from NPWS or other specialist for advice about obligations under the Threatened Species Conservation Act, 1995, such as the need to obtain a licence to undertake actions.

Actions include any management works undertaken at the site, or trapping or other survey work that may be necessary to ascetain the presence if the species.


Rainer Rehwinkel has worked extensively with grassy woodlands on the Southern Tablelands. This article is a summary of a talk given at the Managing Grassy Woodlands workshop held at Orange in March 2000.

 


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