Abstract:Abstract. Only a handful of non-human animals are known to grow their own food by cultivating high-yield fungal or algal crops as staple food. Here we report an alternative strategy utilized by an omnivorous marine worm, Hediste diversicolor, to supplement its diet: gardening by sprouting seeds. In addition to having many other known feeding modes, we showed using video recordings and manipulative mesocosm experiments that this species can also behave like gardeners by deliberately burying cordgrass seeds in t… Show more
“…These quadrats were positioned along a 6 m‐long string (marked every 1 m) with each end fixed at a PVC tube. The sowed seeds were first sterilized by freezing them in a −20°C freezer for 2 weeks to prevent seed loss due to germination (Zhu et al ). These seeds were then dyed with Rose Bengal to be distinguished from the ambient seeds and were waterlogged to mimic the naturally settled cordgrass seeds (Zhu et al ).…”
Coastal wetlands such as saltmarshes are valued as prominent buffering ecosystems to global climate change and sea level rise (SLR), yet their long‐term persistence may also be threatened by these global change stressors. While saltmarshes are increasingly thought to be resilient to SLR owing to high vertical marsh adaptability, their long‐term stability remains uncertain due to our poor understanding of marsh resilience at the marsh‐tidal flat interface, where wave disturbance can progressively shift vegetated marsh toward a bare tidal flat state. Here, we explore how SLR affects vegetation recoverability on tidal flats using cordgrass, a globally common saltmarsh foundation species, as a model plant. Combined field and model results demonstrate that small increases in wave forcing due to raised water depth over tidal flats can dramatically weaken or even block vegetation recovery from eroding marsh edges, through hampering seed persistence. Vegetation recovery on tidal flats next to the marsh edge thus represents an unrecognized Achilles' heel of marsh resilience to SLR, which if ignored may cause underestimation of marsh vulnerability. These findings are highly relevant for a more comprehensive assessment of marsh susceptibility to SLR in systems where seeds play an essential role in revegetation of tidal flats, and highlight the importance of maintaining either a wave‐protected or well‐elevated tidal flat near the marsh edge that allows for quick vegetation recovery for supporting resilient marshes.
“…These quadrats were positioned along a 6 m‐long string (marked every 1 m) with each end fixed at a PVC tube. The sowed seeds were first sterilized by freezing them in a −20°C freezer for 2 weeks to prevent seed loss due to germination (Zhu et al ). These seeds were then dyed with Rose Bengal to be distinguished from the ambient seeds and were waterlogged to mimic the naturally settled cordgrass seeds (Zhu et al ).…”
Coastal wetlands such as saltmarshes are valued as prominent buffering ecosystems to global climate change and sea level rise (SLR), yet their long‐term persistence may also be threatened by these global change stressors. While saltmarshes are increasingly thought to be resilient to SLR owing to high vertical marsh adaptability, their long‐term stability remains uncertain due to our poor understanding of marsh resilience at the marsh‐tidal flat interface, where wave disturbance can progressively shift vegetated marsh toward a bare tidal flat state. Here, we explore how SLR affects vegetation recoverability on tidal flats using cordgrass, a globally common saltmarsh foundation species, as a model plant. Combined field and model results demonstrate that small increases in wave forcing due to raised water depth over tidal flats can dramatically weaken or even block vegetation recovery from eroding marsh edges, through hampering seed persistence. Vegetation recovery on tidal flats next to the marsh edge thus represents an unrecognized Achilles' heel of marsh resilience to SLR, which if ignored may cause underestimation of marsh vulnerability. These findings are highly relevant for a more comprehensive assessment of marsh susceptibility to SLR in systems where seeds play an essential role in revegetation of tidal flats, and highlight the importance of maintaining either a wave‐protected or well‐elevated tidal flat near the marsh edge that allows for quick vegetation recovery for supporting resilient marshes.
“…Salt marsh seeds and seedlings need to be able to germinate and survive in a dynamic environment. In earlier studies, the effect of one or two particular parameters on germination and survival of intertidal pioneer vegetation was often studied in laboratory experiments: including sediment dynamics (Boorman et al 2001;Cao et al 2018), inundation regime (Boorman et al 2001;Egan and Ungar 2000), salinity (Keiffer et al 1994), rainfall (Xie et al 2019), temperature (Khan et al 2000;Ungar 1967), and/or bioturbation (van Regteren et al 2017;Zhu et al 2016). Field experiments are much scarcer, but are important as they can provide valuable information on realistic combinations of these environmental parameters.…”
Salt marshes, providing numerous ecosystem services, are degrading worldwide. To effectively aid conservation and restoration efforts, increased knowledge on marsh expansion processes and the initial establishment of pioneer vegetation is essential. In this study, we disentangle environmental drivers that affect the lifecycle of the annual pioneer Salicornia procumbens at the salt marsh edge. We studied the effect of various environmental variables on the start of germination, germination success and mortality before seed-set in a field experiment in the Dutch Wadden Sea at Westhoek. Our results indicate that temperature and sedimentation inhibited the initiation of germination. Once germination occurred, higher precipitation rates increased germination success. In contrast, sedimentation rates above 0.5 mm day −1 halved germination success through burial of freshly sprouted seedlings. Unexpectedly, natural germination was low, indicating that seed availability may have been limited, despite a seed source nearby. Frequent inundation, extended periods without inundation (through desiccation of the soil) and a highly dynamic bed level increased mortality before seed-set. Consequently, bed-level dynamics (erosion, sedimentation and bed-level variation) impact seed production dually (decrease germination and increase mortality) and thus potentially reproduction success. A high seed reproduction is crucial for annuals, such as S. procumbens, to re-establish the following year. Next to advancing our general knowledge of natural salt marsh expansion, results in this study can also be used to assess the potential of a given site for salt marsh stimulation or restoration. Seed availability and local bedlevel dynamics are key in the successful establishment of a salt marsh pioneer: Salicornia procumbens.
“…Ecosystem engineering could have the following benefits: ensure safety (the beaver Castor canadensis; Wright et al 2002), create shelter (shelter-building caterpillars; Lill and Marquis 2003), improve living conditions (seagrass; Bos et al 2007), ensure food availability (sprouting seeds by bristle worms; Zhu et al 2016), and promote the quality of food (through soil compaction; Veldhuis et al 2014). Food supply is a key determinant of habitat choice (Piersma 2012) and consumer demographics (Krebs 1996).…”
Although the ecosystem engineering concept is well established in ecology, cases of joint engineering by multiple species at large scales remain rare. Here, we combine observational studies and exclosure experiments to investigate how co‐occurring greater flamingos Phoenicopterus roseus and fiddler crabs Uca tangeri promote their own and each other's food availability by creating a spatially complex mosaic of depressions (bowls, gullies) and hummocks (plateaus, mounds) in the intertidal zone. This results in a mosaic of microhabitats with different tidal inundation regimes. These microhabitats are spatially organized with labyrinth‐like patterns in the high intertidal zone and spotted patterns in the lower intertidal, both of which likely arise from biophysical interactions between these organisms and hydrodynamic forces. We show that the resulting spatial complexity is vital for biofilm production. The depression microhabitats were wetter and richer in organic matter and biofilms compared with hummocks. Excluding flamingos and crabs resulted in an increase in biofilm biomass over the shorter term (six months), but a decrease over the longer term (after one year). Moreover, our results strongly suggest that these biogeomorphological microhabitats in the mosaics were maintained by the feeding activities of flamingos and to a lesser extent crabs. During a period of flamingo exclusion, all the spotted patterns filled up with sediment, while the exclusion of crabs led to gradual sediment accumulation in the labyrinth‐like patterns. Collectively, these findings provide empirical evidence for large‐scale joint promotion of food availability by multiple taxa in a marine ecosystem.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.