The influence of ungulates on non-native plant invasions in forests and rangelands: a review.

Abstract

Herbivory by wild and domestic ungulates can strongly influence vegetation composition and productivity in forest and range ecosystems. However, the role of ungulates as contributors to the establishment and spread of non-native invasive plants is not well known. Ungulates spread seeds through endozoochory (passing through an animal's digestive tract) or epizoochory (attached to an animal's body); hence, animal-mediated spread of invasive plants is a common phenomenon. Manipulative experiments of ungulate grazing effects on nonnative plant introduction, establishment, and spread are limited. Herbivory can alter successional patterns and rates when selective foraging favors survival, growth, and reproduction of plants with low palatability, although the impact can differ greatly among ecosystems. Descriptive studies in various habitats have shown that non-native species invade sites with or without livestock grazing, and other studies have tested the utility of prescribed grazing to reduce biomass and occurrence of invasive plants. Understanding the cause-effect relations between ungulates and invasive plant dynamics is a critical management need that deserves high priority for research. We summarize existing knowledge and identify gaps and research needs.

Citation

Parks, Catherine G.; Wisdom, Michael J.; Kie, John G. 2005. The influence of ungulates on non-native plant invasions in forests and rangelands: a review. In: Pacific Northwest Region Invasive Plant Program: Preventing and Managing Invasive Plants, Vol. III: Appendix D33-D52