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CANCELLED! Gro Havskov Kirk: Warming impact on dominating plant species in Chinese coastal wetlands

Seminar: Akvatisk biologi

31.05.2019 | Anne Kirstine Mehlsen

Dato tor 06 jun
Tid 09:45 10:30
Sted Institut for Bioscience, Ole Worms Alle 1, bygning 1135-234

Foredragsholder: Gro Havskov Kirk, Akvatisk biologi, AU

ABSTRACT:

Global mean temperature is projected to increase by 1 - 3.7 degrees Celcius by 2100. Increased warming can stimulate the productivity in marsh ecosystems, which already are among the most productive on earth. We examined the effects of increased temperature on two tall grass species that are dominant in Chinese coastal wetlands (Phragmites australis and Spartina alterniflora). Spartina alterniflora is an invasive species in China, and it has spread rapidly since its introduction in 1979, replacing native species. This shift in species composition in Chinese coastal wetlands, from native macrophytes such as Phragmites australis to invasive species such as S. alterniflora, might also be exacerbated by increasing temperatures. Open top chambers (OTCs), passively elevating the air temperature, were set up in two locations in the Yancheng salt marsh area in eastern China. One site was dominated by S. alterniflora and the other by P. australis. Both sites were equipped with six OTCs and six control plots (CP). Photosynthesis, height, flowering percentage and chlorophyll content was measured on site in August 2018, and biomass was collected for elemental tissue analysis of shoots. Despite the contrasting photosynthetic strategies, we found no difference caused by the warming in either species’ photosynthetic parameters. However, P. australis was significantly taller within the OTCs, but no such pattern was found for S. alterniflora. While other effects of climate change, such as increased flooding and elevated saltwater intrusion in coastal wetlands, would potentially favour the highly salt-tolerant invader S. alterniflora in interspecific competition, our study shows that a temperature increase might provide P. australis with a height advantage.

Institut for Bioscience, Offentligheden / Pressen, Medarbejdere