Ecosystems

Temperature acclimation of two globally invasive species

Will climate change make two globally invasive herbs even more invasive?

Invasive plant species negatively affect native species diversity and ecosystem functioning. The threat of invasive plant species to both natural and agricultural ecosystems is substantial, with the UN highlighting them as one of the major barriers to attaining their Sustainable Development Goals. As climatic conditions are a major constraint on the distribution of plant species, climate change can also be a powerful driver of both native and invasive species distributions. Climate warming is likely to shift habitats to higher latitudes and elevations, promoting invasions by species already adapted to higher temperatures, ultimately shifting species distributions globally. With temperatures already rising globally and invasions likely becoming more frequent, it is increasingly important to understand physiological responses of invasive plants to warmer temperatures.

Thick growth of Yellow Flag Iris (Iris pseudacorus) in Washington, USA. Image credit: Washington State Noxious Weed Control Board with permission.

In their new study published in AoBP, Jorgensen et al. examined the acclimation to temperature of two globally invasive species Yellow Flag Iris (Iris pseudacorus) and Purple Loosestrife (Lyhtum salicaria), which share the same habitat type but differ in morphology. Lower canopy photosynthetic rates decreased with high temperature in L. salicaria but were unaffected in I. pseudacorus. L. salicaria showed typical shade-acclimated responses in leaf pigment content and photosynthetic light response curves and was attributed to adaptations to self-shading. Iris pseudacorus did not show any such adaptations, revealing different invasive photosynthetic strategies in the two species. Overall, both species benefitted from elevated temperatures with increased biomass and shoot height, as well as flowering rate in L. salicaria. It was concluded that both species should continue to be recognised as highly invasive under future climate scenarios in management plans, and the impending advancement of their northern ranges seen as a major threat to the health of native ecosystems.

Researcher highlight

Andreas Jørgensen grew up in Denmark where he studied biology from 2016-2020 at Aarhus University. He recently moved to Norway to finish his studies at the Arctic University of Norway in Tromsø as his obsession with the Arctic was too great to resist any longer. He currently holds a bachelor’s degree in biology and has had a special focus on ecology and plant ecophysiology throughout his studies. He has a broad interest in these areas, especially in the context of climate change. He wants to pursue a career within academia where he wishes to contribute to a better understanding of climate change effects on ecosystems. This paper is his first publication, with hopefully many more are to come!

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