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The role of changing climate in driving the shift from perennial grasses to annual succulents in a Mediterranean saltmarsh
- Publication Year :
- 2017
-
Abstract
- Changing climate threatens the structure and function of saltmarshes, which are often severely degraded by other human perturbations. Along the Mediterranean coastline, increasing temperature and decreasing rainfall have been hypothesised to trigger habitat shifts from perennial grasses to annual succulents in fragile saltmarsh ecosystems, such as those fringing the North Adriatic coastline. We used manipulative field experiments to investigate the effects of increased temperature, decreased precipitation and increased inundation period associated with rising sea levels on the dominant species in the lower marsh, the perennial grass Spartina spp. and the annual succulent Salicornia veneta. At ambient inundation, the combined effects of increased temperature and decreased precipitation enhanced soil temperature and decreased soil moisture, resulting in an increased number of plants, height and live biomass of S. veneta, as well as greater dead biomass of Spartina spp. compared with current conditions. Increased inundation reduced the soil redox potential, and resulted in losses of both Spartina spp. and S. veneta, but these negative effects were much more pronounced for S. veneta. An inundation tolerance test confirmed that S. veneta is significantly more vulnerable to rapid increases in inundation than Spartina spp. We conclude that at current inundation, the increasing drought conditions in the North Adriatic Sea are favouring the spread of the annual succulent S. veneta. The increasing spread of these succulents could reduce the future capability of the system to respond to projected increasing sea levels, as S. veneta is highly vulnerable to increased inundation. Synthesis. Our results highlight the complex interactions between different components of changing climate. Management strategies for saltmarshes in the Mediterranean and other microtidal locations facing similar changes in climate should focus on maintaining the freshwater and coastal channels free from blockages to ameliorate the effects of episodic drought/heatwave conditions and increasing the sediment supply and preventing coastal squeeze to enhance the resilience of the system to the continuous threat of sea level rise.
- Subjects :
- 0106 biological sciences
Mediterranean climate
010504 meteorology & atmospheric sciences
Perennial plant
Evolution
rainfall
Plant Science
01 natural sciences
Spartina patens
climate change
grasses
habitat shifts
inundation
saltmarsh resilience
sea level rise
succulents
temperature
Ecology
Behavior and Systematics
Ecosystem
Marine ecosystem
habitat shift
Ecology, Evolution, Behavior and Systematics
0105 earth and related environmental sciences
geography
Biomass (ecology)
Spartina
geography.geographical_feature_category
biology
010604 marine biology & hydrobiology
biology.organism_classification
Ecology, Evolution, Behavior and Systematic
Salt marsh
grasse
Environmental science
succulent
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....799013ae654d785b00a3b17e7d9eef99