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Keywords:

  • Burrows;
  • Grazing;
  • Mounds;
  • Plant composition;
  • Riparian;
  • Soil disturbance;
  • Wombat

Abstract

Question

Is the composition of groundstorey vegetation influenced by wombat burrowing and mound construction as well as streambank tracks by domestic cattle at high and low levels of usage?

Location

Sixteen streambank study sites in an agricultural area in Kangaroo Valley, southeastern New South Wales, Australia.

Methods

We examined the effects of cattle and wombats on vegetation by measuring plant and litter cover on three markedly different microsites; wombat mounds, the network of tracks used by both cattle and wombats to access pastures away from the riparian area, and control sites that were neither tracks nor mounds, and which were located 1–2 m away from mounds or tracks.

Results

We recorded significantly fewer vascular plant species on the mounds and tracks than on the control microsites, but there were significantly more species at sites of high cattle usage than low cattle usage. Plant cover on the control microsites was more than twice that on the mounds and tracks. The exotic plants, panic veldt grass (Ehrharta erecta) and kikuyu (Pennisetum clandestinum) were typical indicators of high cattle use sites, while wandering jew (Tradescantia fluminensis) and to a lesser extent the unpalatable, low-sprawling shrub mistflower (Ageratina riparia) were indicators of low cattle use sites.

Conclusions

Our study demonstrates that there are few differences in plant community composition between microsites constructed by cattle and those of wombats. Both microsites supported a community that was a subset of the species pool in the surrounding vegetation. Cattle grazing since 1851 in Kangaroo Valley has probably reduced disturbance-sensitive plant species, resulting in an effect that is more apparent at the landscape scale. Further study should focus on the landscape-scale effects of cattle grazing to determine whether cattle or wombats are the major causes of ecosystem degradation in Australian riparian environments.