The Role of Grazing Animals in Controlling Wilding Conifers

Wilding conifers pose a significant environmental threat in New Zealand's high country, endangering native ecosystems. Invasive species like Pinus radiata and Pinus contorta outcompete native flora. Grazing by livestock and wild animals serves as an effective control method. Grazing animals help disrupt wilding conifer establishment by feeding on young seedlings, allowing native plants to flourish. Targeted grazing strategies can optimize this control, with timing being crucial; grazing during germination and early growth phases can greatly reduce conifer establishment. Combining grazing management with other restoration efforts, like mechanical removal, can further enhance wilding conifer control. By leveraging grazing animals' natural behaviors, land managers have the potential to create sustainable strategies that combat invasive conifers and support ecosystem recovery.

Low grazing pressures can significantly impact seedling establishment, particularly in areas with limited seed dispersal. For instance, at Mt Dewar and Flock Hill Stations, reducing stocking levels has resulted in an increase in wilding numbers due to decreased grazing pressure. Additionally, research indicates that rabbits play a crucial role in limiting wilding establishment; the introduction of rabbit haemorrhagic disease (RHD) in 1998 led to a rise in wilding numbers as rabbit populations declined. . While we do not advocate for the use of pests as a management strategy, the research highlights that certain animals can effectively regulate wilding pine establishment.

The application of fertilizers can boost grazing levels and limit the establishment of wildings by intensifying vegetation competition. Nonetheless, it is crucial to weigh this method against possible adverse effects on native plants, as fertilizers might encourage the growth of competitive exotic grasses. Grazing by domestic livestock, particularly sheep, can greatly diminish seedling establishment and can be more effectively controlled through managed stocking levels. The use of fertilizers can further enhance grazing by increasing vegetation competition. Both strategies have their drawbacks, such as potential negative impacts on native vegetation and the necessity for strategic management to balance these effects.

Grazing by domestic animals offers a sustainable way to control wilding conifers in New Zealand's high country, where these invasive species threaten native ecosystems. Utilizing sheep and cattle strategically can help reduce the growth of these conifers by targeting young seedlings. To enhance this approach, the use of fertilizers may promote native vegetation, giving it an advantage over invasive species. However, caution is necessary to avoid overgrazing and soil degradation. Understanding local ecology is essential, as different grazing animals impact vegetation differently. By integrating grazing with careful management, we could be one step closer to tackling the wilding conifer problem while preserving its unique biodiversity.

Mackenzie Wilding Conifer Management Strategy 2016-2030.

Ledgard, N. J., & Norton, D. A. (2008). The impact of browsing on wilding conifers in the South Island high country. NZ Journal of Forestry, 52(4).