Rapid global degradation of coastal habitats can be attributed to anthropogenic activities associated with coastal development, aquaculture, and recreational surface water use. Restoration of degraded habitats has proven challenging and costly, and there is a clear need to develop novel approaches that promote resilience to human‐caused disturbances. Positive interactions between species can mitigate environmental stress and recent work suggests that incorporating positive interactions into restoration efforts may improve restoration outcomes. We hypothesized that the addition of a potential facultative mutualist, the native hard clam (
- Award ID(s):
- 1832178
- NSF-PAR ID:
- 10390584
- Date Published:
- Journal Name:
- BioScience
- Volume:
- 72
- Issue:
- 11
- ISSN:
- 0006-3568
- Page Range / eLocation ID:
- 1088 to 1098
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Mercenaria mercenaria) , could enhance seagrass bed recovery from disturbance. We conducted two experiments to examine the independent and interacting effects of hard clam addition and physical disturbance mimicking propeller scarring on mixed communityZostera marina andHalodule wrightii seagrass beds in North Carolina. Adding clams to seagrass beds exposed to experimental disturbance generally enhanced seagrass summer growth rates and autumn shoot densities. In contrast, clam addition to non‐disturbed seagrass beds did not result in any increase in seagrass growth rates or shoot densities. Clam enhancement of autumn percent cover relative to areas without clam addition was most prominent after Hurricane Dorian, suggesting that clams may also enhance seagrass resilience to repeated disturbances. By June of the next growing season, disturbed areas with clam additions had greater percent cover of seagrass than disturbed areas without clam additions. Beds that were disturbed in April had higher percent cover than areas disturbed in June of the previous growing season. Our results suggest that the timing and occurrence of physical disturbances may modify the ability of clams to facilitate seagrass resiliency and productivity. Understanding when and how to utilize positive, interspecific interactions in coastal restoration is key for improving restoration success rates. -
Abstract Coastal habitat‐forming species provide protection and essential habitat for fisheries but their ability to maintain these services are under threat from novel stressors including rising temperatures. Coastal habitat restoration is a powerful tool to help mitigate the loss of habitat‐forming species, however, many efforts focus on reintroducing a single, imperilled species instead of incorporating alternatives that are more conducive to current and future conditions. Seagrass restoration has seen mixed success in halting local meadow declines but could begin to specifically utilize generalist seagrasses with climate change‐tolerant and opportunistic life history traits including high reproduction rates and rapid growth.
Here, we built on decades of successful eelgrass (
Zostera marina ) restoration in the Chesapeake Bay by experimentally testing seed‐based restoration potential of widgeongrass (Ruppia maritima )—a globally distributed seagrass that can withstand wide ranges of salinities and temperatures. Using field experiments, we evaluated which seeding methods yielded highest widgeongrass survival and growth, tested if seeding widgeongrass adjacent to eelgrass can increase restoration success, and quantified how either seagrass species changes restored bed structure, invertebrate communities, and nitrogen cycling.We found that widgeongrass can be restored via direct seeding in the fall, and that seeding both species maximized total viable restored area. Our pilot restoration area increased by 98% because we seeded widgeongrass in shallow, high temperature waters that are currently unsuitable for eelgrass survival and thus, would remain unseeded via only eelgrass restoration efforts. Restored widgeongrass had higher faunal diversity and double animal abundance per plant biomass than restored eelgrass, whereas restored eelgrass produced three times greater plant biomass per unit area and higher nitrogen recycling in the sediment.
Synthesis and applications. Overall, we provide evidence that supplementing opportunistic, generalist species into habitat restoration is a proactive approach to combat climate change impacts. Specifically, these species can increase trait diversity which, for our study, increased total habitat area restored—a key factor to promote seagrass beds' facilitation cascades, stability, and grass persistence through changing environments. Now, we call for tests to determine if the benefits of restoration with generalist species alone or in conjunction with historically dominant taxa are broadly transferrable to restoration in other marine and terrestrial habitats. -
Restoration is accelerating to reverse global declines of key habitats and recover lost ecosystem functions, particularly in coastal ecosystems. However, there is high uncertainty about the long-term capacity of restored ecosystems to provide habitat and increase biodiversity and the degree to which these ecosystem services are mediated by spatial and temporal environmental variability. We addressed these gaps by sampling fishes biannually for 5–7 years (2012–2018) at 16 sites inside and outside a rapidly expanding restored seagrass meadow in coastal Virginia (USA). Despite substantial among-year variation in abun-dance and species composition, seine catches in restored seagrass beds were consistently larger (6.4 times more fish, p<0.001) and more speciose (2.6 times greater species richness, p<0.001; 3.1 times greater Hill–Shannon diversity, p=0.03) than seine catches in adjacent unvegetated areas. Catches were particularly larger during summer than autumn(p<0.01). Structural equation modeling revealed that depth and water residence time interacted to control seagrass presence, leading to higher fish abundance and richness in shallow, well-flushed areas that supported seagrass. Together, our results indicate that seagrass restoration yields large and consistent benefits for many coastal fishes, but that restoration and its benefits are sensitive to the dynamic seascapes in which restoration is conducted. Consideration of how seascape-scale environmental variability affects the success of habitat restoration and subsequent ecosystem function will improve restoration outcomes and the provisioning of ecosystem services.more » « less
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Abstract Restoration is becoming a vital tool to counteract coastal ecosystem degradation. Modifying transplant designs of habitat-forming organisms from dispersed to clumped can amplify coastal restoration yields as it generates self-facilitation from emergent traits, i.e. traits not expressed by individuals or small clones, but that emerge in clumped individuals or large clones. Here, we advance restoration science by mimicking key emergent traits that locally suppress physical stress using biodegradable establishment structures. Experiments across (sub)tropical and temperate seagrass and salt marsh systems demonstrate greatly enhanced yields when individuals are transplanted within structures mimicking emergent traits that suppress waves or sediment mobility. Specifically, belowground mimics of dense root mats most facilitate seagrasses via sediment stabilization, while mimics of aboveground plant structures most facilitate marsh grasses by reducing stem movement. Mimicking key emergent traits may allow upscaling of restoration in many ecosystems that depend on self-facilitation for persistence, by constraining biological material requirements and implementation costs.more » « less