Abiotic and Biotic Interactions Control Ruppia maritima Life History Development Within a Heterogeneous Coastal Landscape

Strazisar, Theresa; Koch, Marguerite S.; Santangelo, Carl W.; Madden, Christopher J.

doi:10.1007/s12237-020-00870-6

Cited by 2 publications

(1 citation statement)

References 73 publications

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“…However, it is also possible that a more stressful environment may already manifest early in the season and induce lower productivity/respiration ratios in the seedlings (see Figure 3 and Box 1 ). This lower P/R ratio may induce the plant to invest more resources into sexual reproduction, which is also suggested by a review of the effect of disturbance on sexual reproduction in seagrasses by Cabaço and Santos [ 51 ], and supported by later studies, for example, showing relations between sexual reproductive effort and temperature [ 52 , 53 , 54 ], but see [ 55 ], desiccation [ 43 , 56 ], nutrients [ 57 , 58 ], mechanical disturbance [ 59 ], and high salinity [ 60 ].…”

Section: What Mechanisms May Induce An Annual or Perennial Life Cycle...mentioning

confidence: 70%

Facultative Annual Life Cycles in Seagrasses

Katwijk

Tussenbroek

2023

Plants

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Plant species usually have either annual or perennial life cycles, but facultative annual species have annual or perennial populations depending on their environment. In terrestrial angiosperms, facultative annual species are rare, with wild rice being one of the few examples. Our review shows that in marine angiosperms (seagrasses) facultative annual species are more common: six (of 63) seagrass species are facultative annual. It concerns Zostera marina, Z. japonica, Halophila decipiens, H. beccarii, Ruppia maritima, and R. spiralis. The annual populations generally produce five times more seeds than their conspecific perennial populations. Facultative annual seagrass species occur worldwide. Populations of seagrasses are commonly perennial, but the facultative annual species had annual populations when exposed to desiccation, anoxia-related factors, shading, or heat stress. A system-wide ‘experiment’ (closure of two out of three connected estuaries for large-scale coastal protection works) showed that the initial annual Z. marina population could shift to a perennial life cycle within 5 years, depending on environmental circumstances. We discuss potential mechanisms and implications for plant culture. Further exploration of flexible life histories in plant species, and seagrasses in particular, may aid in answering questions about trade-offs between vegetative and sexual reproduction, and preprogrammed senescence.

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Section: What Mechanisms May Induce An Annual or Perennial Life Cycle...mentioning

confidence: 70%

Facultative Annual Life Cycles in Seagrasses

Katwijk

Tussenbroek

2023

Plants

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The Ability of Ruppia polycarpa to Regenerate from Seed Depends on Seasonal Porewater Salinity Dynamics and Declining Winter Rainfall Could Delay Recruitment

Webster

Lavery

Strydom

et al. 2023

Estuaries and Coasts

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For many plants, regeneration from seed is vital for population recovery. Climate change is modifying the global hydrological cycle and a primary factor controlling germination of marine plants: salinity. How altered salinity regimes, and especially altered porewater salinity regimes, will regulate early life history stages of estuarine seagrasses is poorly understood. Here, we quantified the porewater salinity dynamics in two ephemeral estuaries that are dominated by the cosmopolitan genus Ruppia. Seedbank, germlings (germinated seeds) and seedlings were found in salinities ranging from 5 to 110 over an annual cycle. To understand the germination ecology of the dominant species, Ruppia polycarpa, seeds were exposed to treatments simulating current salinity regimes and those predicted under climate change. Seeds underwent a Dormancy treatment (15, 60, 150) followed by a Germination treatment (10, 20, 80). Generally, early life history stages were positively affected by hypersaline dormancy conditions if the subsequent Germination salinity was ≤ 20. Germination success was significantly higher for seeds transferred to 10 (65%) compared to 20 (49%) whilst no seeds germinated in 80 highlighting the risk of lower germination as estuaries become drier and more hypersaline with declining winter rainfall. However, germlings were found in situ in salinities ≥ 80 suggesting aspects of the salinity dynamics, not captured by our experimental conditions, may broaden tolerances. Dormant seeds were continuously present in situ and seedlings were observed throughout the whole of the growing season. These results are indicative of bet-hedging strategies. Future research should explore the capacity of these strategies to afford resilience to R. polycarpa to salinity variability under climate change.

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Abiotic and Biotic Interactions Control Ruppia maritima Life History Development Within a Heterogeneous Coastal Landscape

Cited by 2 publications

References 73 publications

Facultative Annual Life Cycles in Seagrasses

Facultative Annual Life Cycles in Seagrasses

The Ability of Ruppia polycarpa to Regenerate from Seed Depends on Seasonal Porewater Salinity Dynamics and Declining Winter Rainfall Could Delay Recruitment

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