Alien Plant Invasion in Mixed-Grass Prairie: Effects of Vegetation Type and Anthropogenic Disturbance
Larson DL, Anderson PJ, Newton W. 2001. Alien Plant Invasion in Mixed-Grass Prairie: Effects of Vegetation Type and Anthropogenic Disturbance. Ecological Applications. 11(1):128-141
The ability of alien plant species to invade a region depends not only on attributes of the plant, but on characteristics of the habitat being invaded. Here we examine characteristics that may influence the success of alien plant invasion in mixed-grass prairie at THRO. The park consists of 2 geographically separate units with similar vegetation types and management history, which allowed us to examine the effects of native vegetation type, anthropogenic disturbance, and the separate park units on the invasion of native plant communities by alien plant species common to counties surrounding both park units. If matters of chance related to availability of propagules and transient establishment opportunities determine the success of invasion, park unit and anthropogenic disturbance should better explain the variation in alien plant frequency,. If invasibility is more strongly related to biotic or physical characteristics of the native plant communities, models of alien plant occurrence should include vegetation type as an explanatory variable. We examined more than 1300 transects across all vegetation types in both units. Akaike's Information Criterion indicated that the fully parameterized model, including the interaction among vegetation type, disturbance, and park unit, best described the distribution of both total number of alien plants per transect and frequency of alien plants on transects where they occurred. Althogh all vegetation types were invaded by alien plants, mesic communities had both greater numbers and higher frequencies of alien plants than did drier communities. A strong element of stochasticity, reflected in differences in frequencies of individual species between the two park units, suggests that prediction of risk of invasion will always involve uncertainty. In addition, despite well-documented associations between anthropogenic disturbance and alien plant invasion, five or the six most abundant alien species at THRO had distributions unrelated to disturbance. We recommend that vegetation type be explicitly taken into account when designing monitoring plans for alien species in natural areas.
- Type
- Journal Article
- Authors
- Larson, Diane; Anderson, Patrick; Newton, Wesley
- Units
- THRO
- Keywords
- Alien Plants, Anthropogenic Disturbance, Great Plains, mixed-grass prairie, native vegetation type, North Dakota, Plant Studies, Theodore Roosevelt National Park