‘Hungary’ for information on the interacting impacts of climate change and disturbance

This summary highlights the work of Hungarian researchers who were interested in teasing apart the individual and interacting effects of drought and disturbance on the establishment and growth of invasive plant species. And - spoiler alert - three of the four plant species they studied are North American natives that have become invasive in Europe.

Orbán et al. (2021). The role of disturbance in invasive plant establishment in a changing climate: insights from a drought experiment. Biological Invasions volume 23, pages 1877–1890 (2021). PDF.

Summary

Climate change and disturbance are two major factors affecting the establishment of invasive species, yet few studies have taken to the field to assess the individual and interactive effects of these two factors. Most studies have found disturbance facilitates the establishment of invading species, while climate change can have a positive or negative effect by altering abiotic conditions, or indirectly modifying species interactions. The researchers focused on the effects of drought, a frequent component of climate change, in this study and tested whether drought disturbance and their combination affect the emergence, survival and growth of invasive plant species in Central Hungary. They selected four prevalent invasive species in Europe, representing different life forms, including the annual forb Ambrosia artemisiifolia (common ragweed), the annual grass Cenchrus incertus (common sanbur), perennial forb Asclepias syriaca (common milkweed), and the deciduous tree Ailanthus altissima (tree of heaven), in drought and non-drought plots with and without soil disturbance. All of these species, except for A. altissima, are native to North America and invasive in Europe. In the end, A. altissima was eliminated from the analysis due to lack of emergence in any of the plots.

Take home points

  • Drought alone hindered the emergence of all three invasive plant species, but disturbance enhanced it, confirming that disturbance is a more influential factor in facilitating invasive plant establishment.

  • Different life stages of invasive plants will be impacted differently by drought and disturbance, but overall drought inhibits invasive plant species success while disturbance helps it.

  • Presence of competing native vegetation was an important factor in deterring invasive plant establishment.

Management implications

  • Disturbed areas are more vulnerable to the establishment of invasive plants and disturbance in priority habitats should be avoided.

  • Given that different components of climate change will influence invasive species in different ways, extreme weather events that cause disturbance should be a greater concern for invasive plant managers than drought.

  • Incorporating early detection and rapid response efforts into extreme weather event response plans is important to avoid the establishment of new invasive plant populations.

  • The effects of climate change are not always in favor of the spread of invasive species, therefore research into which components facilitate the spread of invasives will be important to understand how to manage for invasive species in light of climate change.

Keywords

Biological invasion, Climate change, Drought, Seedling emergence, Soil disturbance