A review of issues in seagrass seed dormancy and germination:implications for conservation and restoration

Orth, Robert J.; Harwell, Matthew C.; Bailey, Eva M.; Bartholomew, Aaron; Jawad, Jennifer T.; Lombana, Alfonso V.; Moore, Kenneth A.; Rhode, Jennifer M.; Woods, Helen E.

doi:10.3354/meps200277

Cited by 183 publications

(127 citation statements)

References 88 publications

Supporting

Mentioning

116

Contrasting

Unclassified

Order By: Relevance

“…Therefore, these findings are similar to those for temperate seagrasses (Marba & Duarte 1997) and suggest that the periods of drought that were experienced between 2002 and 2006, when the Norman River almost completely stopped flowing, may have been detrimental by not supplying sufficient nutrients to seagrass meadows. Alternative explanations for the positive effect of river flow could also relate to the effect of salinity on the germination of seeds (Orth et al 2000). Although we document the major correlates of seagrass in the dry season, seagrass biomass was recorded to be higher in the wet season.…”

Section: Discussionmentioning

confidence: 46%

Long-term climate-associated dynamics of a tropical seagrass meadow: implications for the future

Rasheed¹,

Unsworth²

2011

Mar. Ecol. Prog. Ser.

107

View full text Add to dashboard Cite

The long-term changes of tropical intertidal seagrass, mainly Halodule uninervis and Halophila ovalis meadows and their relationship to climate are poorly documented. Developing a greater understanding of the effects of climate on seagrass meadows is critical for estimating the effects of future climate change scenarios. Here we document the temporal dynamics of coastal intertidal seagrass in tropical northeast Australia over 16 yr of detailed monitoring. This study is the first to directly relate such change to long-term climate variability in the Indo-Pacific region and southern hemisphere. Regression modelling was used to relate seagrass biomass and meadow area measurements to climate data. The aboveground biomass and area of the meadow were correlated with the interacting factors of air temperature, precipitation, daytime tidal exposure and freshwater runoff from nearby rivers. Elevated temperature and reduced flow from rivers were significantly correlated (R 2 = 0.6, p < 0.001) with periods of lower seagrass biomass. Results of this study have important implications for the long-term viability of seagrasses with regard to climate change scenarios. Modelling of our findings indicates that future higher temperatures could be detrimental to Indo-Pacific intertidal, coastal and estuarine seagrass meadows.KEY WORDS: Climate change · Global warming · Halophila ovalis · Halodule uninervis · Temperature · Rainfall · Indo-Pacific · Queensland · Australia Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 422: [93][94][95][96][97][98][99][100][101][102][103] 2011 been lost at an unprecedented rate from a variety of anthropogenic influences (Waycott et al. 2009). Predictions of the influence of climate change scenarios on seagrass (Short & Neckles 1999, Harley et al. 2006, Poloczanska et al. 2007, Waycott et al. 2007) are largely based on incidences of seagrass loss associated with extreme weather (Cardoso et al. 2008, Micheli et al. 2008 as reported in short-term experimental studies (Campbell et al. 2006). Long-term studies directly measuring seagrass changes and how they are correlated with climate are rare. Such studies are restricted to the Mediterranean Sea and coastal areas of Florida (Marba & Duarte 1997, Tomasko et al. 2005; no similar studies have been reported for the tropical Indo-Pacific region.Throughout the Indo-Pacific region, turbid estuarine and coastal environments commonly contain abundant and productive intertidal seagrass meadows dominated by the small colonising floral species of Halodule uninervis (Forssk.) Aschers., 1882 and Halophila ovalis (R.Br.) J. D. Hooker, 1858, Coles et al. 2003. Such meadows are often spatially expansive , Coles et al. 2003 and are particularly important food sources for dugong Dugong dugong and green turtles Chelonia mydas (Bjorndal 1985, Preen & Marsh 1995. The intertidal and coastal location of these meadows makes them susceptible to large climatic events, such as flooding , Campbell & McKenzie 2004, drought...

show abstract

Section: Discussionmentioning

confidence: 46%

Long-term climate-associated dynamics of a tropical seagrass meadow: implications for the future

Rasheed¹,

Unsworth²

2011

Mar. Ecol. Prog. Ser.

107

View full text Add to dashboard Cite

show abstract

“…Their distribution depends on sediment characteristics (sandy, not rocky shore) and turbidity caused by biotic or abiotic factors (see, e.g., Orth et al, 2000). Zostera nzarina often dominates worldwide seagrass communities.…”

Section: A Angiospermsmentioning

confidence: 99%

Allelopathy of Aquatic Autotrophs

Gross¹

2003

Critical Reviews in Plant Sciences

542

355

View full text Add to dashboard Cite

Allelopathy in aquatic environments may provide a competitive advantage to angiosperms, algae, or cyanobacteria in their interaction with other primary producers. Allelopathy can influence the competition between different photoautotrophs for resources and change the succession of species, for exarnple, in phytoplankton cornmunities. Field evidence and laboratory studies indicate that allelopathy occurs in all aquatic habitats (marine and freshwater), and that ail prirnary producing organisms (cyanobacteria, micro-and macroalgae as well as angiospenns) are capable of producing and releasing allelopathically active compounds. Although allelopathy also includes positive (stimulating) interactions, the majority of studies describe the inhibitory activity of ailelopathicaily active compounds. Different mechanisms operate depending on whether allelopathy takes place in the Open water (pelagic zone) or is Substrate associated (benthic habitats). Allelopathical interactions are especiaily common in fully aquatic species, such as submersed macrophytes or benthic algae and cyanobacteria. The prevention of shading by epiphytic and planktonic primary producers and the competition for space may be the ultimate cause for allelopathical interactions. Aquatic ailelochemicals often target multiple physiological processes. The inhibition of photosynthesis of competing primary producers seems tobe a frequent mode of action. Multiple biotic and abiotic factors determine the strength of allelopathic interactions. Bacteria associated with the donor or target organism can metabolize excreted aiielochemicals. Frequently, the impact of surplus or limiting nutrients has been shown to affect the overail production of allelochemicals and their effect on target species. Similarities and differences of ailelopathic interactions in marine and freshwater habitats as well as between the different types of producing organisms are discussed.

show abstract

“…They occur in dense aggregations in shallow coastal habitats worldwide (den Hartog 1970, Phillips & Menez 1988 and provide important ecological functions in the areas in which they occur (reviewed in Larkum et al 2006). Despite their long evolutionary history, seagrass populations are now challenged with rapid environmental changes as a result of coastal human population pressures (Short & Wyllie-Echeverria 1996, Bull et al 2004, Ralph et al 2006, and understanding patterns and sources of variation in adult reproduction and seedling recruitment is critically important to ongoing conservation and management efforts (Orth et al 2000, 2006a,b, Duarte 2002.…”

Section: Introductionmentioning

confidence: 99%

Patterns and sources of variation in flowering, seed supply and seedling recruitment in surfgrass Phyllospadix torreyi

Reed

Holbrook²,

Blanchette³

et al. 2009

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Knowledge of patterns and sources of variation in adult reproduction and juvenile recruitment is essential for understanding the dynamics of populations and their capacity to recover from disturbances. In-depth knowledge of this kind is lacking for many species of seagrass. Here we examined the degree to which temporal and spatial variation in seedling density in the surfgrass Phyllospadix torreyi was explained by the local production and deposition of seeds. We did this by measuring floral density, seed production, seed supply and seedling recruitment at 5 sites near Santa Barbara, California, USA, over a 4 yr period. We found that the local density of dehisced female spadices explained nearly 41% of the variation in the number of seeds caught in seed traps. Large seed crops were common in the absence of nearby males and noticeable numbers of seeds were periodically caught in traps when female flowers were locally rare or absent, suggesting that pollen and seed dispersal occasionally occurred over distances greater than the scale of our study sites (i.e. > 50 m). Overall, the summer densities of female spadices at a site explained > 60% of the variation in the density of seedlings that recruited to the site the following winter. Deviations from positive associations among surfgrass flowers, seeds and seedlings appeared to reflect interannual variability in environmental conditions. Most notable was the coincidence of universally low fruit production and seedling recruitment during the 1997-1998 El Niño event. Seedling density varied independently of rates of seed deposition when all years were examined, but was highly dependent on rates of seed supply when the seedling data from the 1998 El Niño winter were omitted from the analysis. Collectively, our observations demonstrated significant coupling between adult reproduction and local recruitment in surfgrass that was interrupted by adverse growing conditions associated with the 1997-1998 El Niño.

show abstract

A review of issues in seagrass seed dormancy and germination:implications for conservation and restoration

Cited by 183 publications

References 88 publications

Long-term climate-associated dynamics of a tropical seagrass meadow: implications for the future

Long-term climate-associated dynamics of a tropical seagrass meadow: implications for the future

Allelopathy of Aquatic Autotrophs

Patterns and sources of variation in flowering, seed supply and seedling recruitment in surfgrass Phyllospadix torreyi

Contact Info

Product

Resources

About