Are stressful ecosystems less invasible? Global plant invasion patterns, research gaps and consequences for conservation

Background/Question/Methods

Ecologists have long observed that ecosystems with greater resource availability, disturbance, and less climatic stress are usually those that harbor the greatest numbers of invasive plants, and are considered more invasible than ecosystems or biomes with lower resource availability, or higher climatic stress. However, other factors, such as propagule pressure and human disturbance regimes, are increasingly shown to be key factors in successful plant invasions, and may be more important than the environmental limitations of invaded ecosystems. We summarize the current status of plant invader richness across biomes globally,and question the potential mechanisms that have produced invasion patterns to date. We then ask whether these factors may help us predict and prevent the incidence of future invasions in climatically stressful ecosystems.

Results/Conclusions

As expected, we find that deserts and tundras have few invaders. We also find that the identities of invaders in deserts and tundras are unique, while ecosystems limited by factors other than climate share a similar complement of invasive plant species. We conclude that plant invasions may be strongly limited by climatic stress, but that plant invaders that are successful under different regimeges of climate stress are likely to surface in the future, and these invasions will have major impacts as stressful ecosystems experience greater human exploitation. As some of the most vast, pristine and least-invaded regions on earth, stressful ecosystems have great potential and a pressing need for conservation.