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The role of changing climate in driving the shift from perennial grasses to annual succulents in a Mediterranean saltmarsh

Citation

Strain, EMA and van Belzen, J and Comandini, P and Wong, J and Bouma, TJ and Airoldi, L, The role of changing climate in driving the shift from perennial grasses to annual succulents in a Mediterranean saltmarsh, Journal of Ecology, 105, (5) pp. 1374-1385. ISSN 0022-0477 (2017) [Refereed Article]

Copyright Statement

Copyright 2017 The Authors

DOI: doi:10.1111/1365-2745.12799

Abstract

  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.

Item Details

Item Type:Refereed Article
Keywords:climate change, grasses, habitat shifts, inundation, rainfall, saltmarsh resilience, sea level rise, succulents, temperature
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Assessment and management of benthic marine ecosystems
UTAS Author:Strain, EMA (Dr Beth Strain)
ID Code:141410
Year Published:2017
Web of Science® Times Cited:11
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2020-10-19
Last Modified:2020-11-24
Downloads:0

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