As our climate warms non-native plant species, introduced for their aesthetic appeal, have the potential to naturalize. Associate Editor, Rafael Zenni discusses research by Emily Haeuser and colleagues that aims to manage this risk. European ornamental garden flora as an invasion debt under climate change is published in Journal of Applied Ecology.

A Portuguese version of this post is available here.

Physostegia virginiana By R. A. Nonenmacher from Wikimedia Commons

Thousands of plant species have been moved beyond their native ranges for ornamental purposes. The choices of species for gardens, streets, and urban parks are based largely on aesthetic, cultural, and utilitarian reasons and not for their ecological or climatic suitability for a specific region. Many of these ornamental plants currently cultivated in places beyond their ideal climate niche might be able to survive and grow but may be unable to reproduce and form sustainable populations. Without human care, many non-native ornamental plants would perish. And this is a good thing. We want these non-native species to depend on human cultivation. Otherwise they might spread to native habitats and invade, producing negative impacts. However, now that our climate is rapidly changing (i.e. average temperatures are rising and there has been a decrease in the number of days with below freezing temperatures), it is possible that places so far physiologically limiting for some non-native species will become less harsh. This could allow non-native species to reproduce successfully – a process called naturalization.

In order to evaluate which ornamental plant species in Europe may be able to naturalize under projected future climates, a group of researchers led by Dr. Emily Haeuser modelled the potential future naturalization success for 1583 species not-yet-naturalized ornamental non-native species of the European Garden Flora. They generated a list of plants most likely to naturalize in Europe in the near future and found that naturalization probability increased for 41 species. In contrast, only one species had its naturalization probability decreased under climate change. Particular management plans should therefore be considered to prevent naturalization of those species likely to naturalize in the near future.

Identifying likely future invasive species is key to successful management plans. To prevent the spread and impact of invasive species is always the best and cheapest option. This article, The European ornamental garden flora as an invasion debt under climate change, led by Emily Haeuser and published in Journal of Applied Ecology is a step forward in that direction. The methods and results the team present show relevance to many other non-native floras around the world.

Read the full paper, European ornamental garden flora as an invasion debt under climate change in Journal of Applied Ecology.