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Prof. Shaolin Peng’s team in the School of Life Sciences found a new mechanism of mangrove expansion to high latitude on the east coast of North America

Last updated :2020-03-23

Source: School of Life Sciences
Written by: School of Life Sciences
Edited by: Xu Jia, Wang Dongmei

Recently,the team of Prof. Shaolin Peng from the School of Life Sciences at Sun Yat-sen University in collaboration with Prof. James E. Byers from the University of Georgia published a research paper, entitled “Freeze-tolerance of poleward-spreading mangrove species weakened by soil properties of resident salt marsh competitor”, in Journal of Ecology (IF5y=6.817). Prof. Shaolin Peng and Prof. James E. Byers are the corresponding author, and PhD student Enjian Chen is the first author.

Increasing temperatures associated with climate change are shifting plant species to higher latitudes. Soil communities could aid the plants’ shift into novel areas by harbouring fewer soil-borne antagonists or more mutualists that influence the fitness and stress tolerance of the shifting species. Alternatively, they could contain novel antagonists or fewer mutualists. Thus, soil communities could positively or negatively affect plant range expansion, particularly if they influence plants’ responses to climate, such as freeze tolerance, that feedback to affect expansion.

The team of Prof. Shaolin Peng used the northward range expansion of the black mangrove, Avicennia germinans, into a system dominated by marsh cordgrass, Spartina alterniflora, in northern Florida, USA to study how the novel soil environment (i.e., S. alterniflora soil) affects mangrove fitness, susceptibility to cold stress, and the colonization of mutualist fungi. This research found that S. alterniflora soil could impede A. germinans establishment in salt marsh communities. However, mild winters give A. germinans a chance to survive with minimal mutualist assistance and less opportunity for antagonists to accentuate freeze stress. As A. germinans displaces S. alterniflora, the resulting switch in the plants’ relative abundance should increasingly benefit A. germinans due to increased proximity to beneficial mutualists and dilution of the inhibitory factors associated with S. alterniflora soil that will thereby improve A. germinans growth and freeze tolerance. Several mild winters in a row could thus provide a “window of opportunity” for A. germinans to accentuate such a positive plant-soil feedback, which could increase its population growth within an invaded site (Figure).

Figure: The mechanism of how A. germinans successfully replaced S. alterniflora under different frequencies of freezing events

The research demonstrates that it is essential to consider plant-soil interactions in the context of climate variables that mediate expansion. Soil constituents can inhibit or facilitate climate-driven plant expansions by altering plant stress tolerance to freezing.

This work was supported by Vegegraphy of China (2015FY210200-13), Chinese Scholarship Council and Zhang Hongda Science Foundation in Sun Yat-sen University.

Link to the paper: https://doi.org/10.1111/1365-2745.13350