Successful management of invasive plant species may depend on focusing management on source populations. Therefore, efficient means to identify populations that are most likely to contribute to further invasion are critical. The success of plant populations varies spatially and temporally on the landscape as a result of environmental and climate variables. Populations at the edges of a species’ eco-physiological range are likely to have lower population growth rates and higher population turnover. Plus, species’ reproductive strategies are likely to shift along this gradient, which may result in similar overall growth rates but different levels of resilience to perturbations to the system, including control practices. We used a number of plant population and metapopulation metrics to evaluate the dynamics of a range of non-native plant species (Bromus tectorum, Centaurea stoebe, Cirsium arvensis, Linaria dalmatica, Linaria vulgaris), and their management along their environmental suitability gradients as part of our studies in the Greater Yellowstone Ecosystem.
Results/Conclusions
We found that various plant metrics including abundance, invasiveness and reproductive growth rate of non-native plant species increased along the environmental suitability gradient for each species, with the exception of B. tectorum that showed no trend. The reproductive strategy of L. dalmatica (only species assessed) changed from dominance of vegetative to seed reproduction as the environmental suitability increased. The impact of non-native plant species on plant richness and diversity did not show a conclusive pattern with the environmental suitability gradient for the four species evaluated, although there was a pattern of higher total non-native species richness at sites predicted to be more suitable. These results suggest that non-native plant management should be directed at populations established in areas of higher predicted environmental suitability. Concurrent studies demonstrated higher herbicide efficacy for B. tectorum, C. stoebe, C. arvensis and L. vulgaris in more suitable environments, but also higher population recovery at such sites. These results suggest that management should be targeted at populations in sites predicted to be more suitable for a particular species as herbicide will likely be more effective.