An evaluation of the effectiveness of WR-1 repellent for browsing control in HEMS forest.  J. D. Delbridge and M. T. Lutze.  November 1998.  12pp. (unpubl.)

SUMMARY

Throughout the high elevation mixed species (HEMS) forest of East Gippsland, damage to eucalypt seedlings from high levels of animal browsing has led to unacceptably low stocking in the regenerating forest. A trial was established at Buldah to determine the efficiency of a repellent (WR-1) in protecting planted eucalypt seedlings from browsing by the native swamp wallaby (Wallabia bicolor) and the European rabbit (Oryctolagus cuniculus) in August 1996. The trial was established in a native forest coupe in HEMS forest near Buldah in far East Gippsland. The regeneration at the site was considered to be at severe risk of failure through browsing, because browsing had been implicated in the failure of previous regeneration attempts.

Repellent was applied to cut-tail (Eucalyptus fastigata) seedlings in the nursery prior to planting in spring. Control seedlings, also cut-tail, with no repellent were also planted as part of the design. Post-planting, seedlings were assessed to determine the severity of browsing damage at monthly intervals.

No statistically significant differences were apparent between the treated seedlings and control seedlings (p > 0.05) at any assessment. In all treatments browsing occurred from 2 weeks after planting, progressively increased to very high levels to 3 months after planting, and at 12 months after planting, mortality had reached 99%.

Although wallaby and rabbit browsing was observed as the main cause of seedling mortality, additional factors included heat induced desiccation of leaves, and insect browsing.

Treatment of seedlings with WR-1 repellent failed to prevent regeneration failure as a result of animal browsing on this site of extreme browsing pressure. Further study of browsing control on sites of extreme browsing pressure should involve integrated control methods.