Explore the root advantages of invasive plants under nutrient enrichment

Explore the root advantages of invasive plants under nutrient enrichment

In this new post, Hao Liu—a postdoc from Fudan University, China—presents his work ‘Root plasticity benefits a global invasive species in eutrophic coastal wetlands’. Here he discusses the importance in plasticity for invasive species success, highlights the cohesion required to work in the mud, and shares his journey in ecology.

About the paper
Invasive species usually benefit more than native species from increases in nutrient availability. The superiority of invasive species may be attributed to their intrinsic advantages and high phenotypic plasticity in functional traits. However, little is known about the contribution of root plasticity to invasiveness under increased nutrient availability. Spartina alterniflora is a notorious plant that invades coastal wetlands worldwide, threatening native biodiversity and ecosystem services. Human-induced coastal eutrophication was found to promote its invasion. We believe that this is not simply because it has more roots than native species and we attempt to investigate if and how root trait plasticity contributes the ascendancy of invasive plants following nutrient enrichment.

Using a 3-year field nitrogen enrichment experiment, we found that S. alterniflora exhibited high plasticity in root traits in response to N enrichment, whereas the root traits of native Phragmites australis largely remained unresponsive to fertilization. A series of plastic adjustments in architectural, morphological, chemical and anatomical root traits jointly resulted in fast nutrient uptake and transportation in S. alterniflora, boosting its above-ground productivity under fertile N conditions.

Washed roots of Spartina alterniflora (left) and Phragmite australis (right) (credit: Hao Liu)

About the research
This paper improves our understanding of below-ground mechanisms underlying invasion under nutrient enrichment. Of course, future studies including more invasive species are required to detangle below-ground mechanisms underlying invasion under global change. A better understanding of the roots of invasive species is helpful for a better management and control of invasion. After all, when it comes to invasive species control, there is always the question of how to deal with the plant’s stubborn roots.

Our research in salt marshes is ongoing, we are curious about the response of root turnover to nitrogen enrichment, and we are also interested in the effects of root adaptations on ecosystem functioning, such as soil carbon sequestration. In addition, we hope to explore the role of roots in the mechanisms and consequences of plant invasion in other ecosystems in the future.

Continuous monitoring and sampling in the coastal wetlands were laborious—sometimes it is difficult to just walk in salt marshes. The laboratory works, including root washing and trait measurements, were tedious and required patience. Fortunately, our team is cohesive and collaborates effectively in our projects.

Walking in muddy coastal wetlands (credit: Hao Liu)
Monthly monitoring of root turnover (credit: Hao Liu)
Team members conducting surveys on the SINE experiment (credit: Hao Liu)

About the author
When I was a kid, I was confused that the rivers in my hometown were covered by a kind of water plant in a short time. I learned later that that plant was Alternanthera philoxeroides—an invasive species. I found that the seemingly ordinary plants around us are actually full of the mysteries of nature when I got involved in ecology. I have a bachelor’s degree in geography, but my focus during my master’s degree was benthic diatoms in rivers. I started digging plant roots and focusing on root functions during my PhD studies. Now as a postdoctoral fellow at Fudan University, I am continuing my research on the root functions and their impact on ecosystem functions in salt marshes. I hope to continue doing research in ecology and answer more ecological questions in the future.

Enjoyed the blogpost? Read the research here!

Hao Liu, with native Scirpus mariqueter and Phragmites australis marshes in the background
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