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As coastal regions experience accelerating land loss, artificial substrates may be useful in restoration efforts to replenish sediment and facilitate plant colonization. Recycled glass sand is a potential artificial substrate for marsh building due to its sustainability, availability, and similarity to natural substrates. However, differences in texture and availability of microbiota necessitate investigating how it affects plant growth. We tested the effect of three substrates (conventionally used dredged river sand, recycled glass sand, and a mix) and inoculation with natural soil microbes on the biomass and root architecture of Black mangrove (Avicennia germinans) in a greenhouse experiment. We found neither substrate nor inoculum affected biomass; however, survival was lower in mixed substrate compared to dredged and glass sand, and live inoculum increased survival from 70 to 93%. Substrate affected root architecture: mangroves grown in glass sand had 55% lower fine root length, 51% lower specific root length (length/mass), and 26% larger average root diameter than mangroves grown in dredged sand. Although an unintended fungal infection byGeotrichum candidumkilled nearly 90% of infected propagules before the experiment, surviving plants had 81% higher biomass than uninfected plants. These findings suggest that while glass sand does not affect biomass, it may affect root architecture in ways that compromise soil stability. Furthermore, inoculation with live soil may boost restoration planting success across substrates, likely by reintroducing mutualists. Overall, recycled glass sand may be a viable restoration strategy with the caveat that the developing root architecture may differ from that in more natural substrates. 

Abstract Accompanying the climate crisis is the more enigmatic biodiversity crisis. Rapid reorganization of biodiversity due to global environmental change has defied prediction and tested the basic tenets of conservation and restoration. Conceptual and practical innovation is needed to support decision making in the face of these unprecedented shifts. Critical questions include: How can we generalize biodiversity change at the community level? When are systems able to reorganize and maintain integrity, and when does abiotic change result in collapse or restructuring? How does this understanding provide a template to guide when and how to intervene in conservation and restoration? To this end, we frame changes in community organization as the modulation of external abiotic drivers on the internal topology of species interactions, using plant–plant interactions in terrestrial communities as a starting point. We then explore how this framing can help translate available data on species abundance and trait distributions to corresponding decisions in management. Given the expectation that community response and reorganization are highly complex, the external‐driver internal‐topology (EDIT) framework offers a way to capture general patterns of biodiversity that can help guide resilience and adaptation in changing environments. 

Abstract Bacterial and fungal root endophytes can impact the fitness of their host plants, but the relative importance of drivers for root endophyte communities is not well known. Host plant species, the composition and density of the surrounding plants, space, and abiotic drivers could significantly affect bacterial and fungal root endophyte communities. We investigated their influence in endophyte communities of alpine plants across a harsh high mountain landscape using high-throughput sequencing. There was less compositional overlap between fungal than bacterial root endophyte communities, with four ‘cosmopolitan’ bacterial OTUs found in every root sampled, but no fungal OTUs found across all samples. We found that host plant species, which included nine species from three families, explained the greatest variation in root endophyte composition for both bacterial and fungal communities. We detected similar levels of variation explained by plant neighborhood, space, and abiotic drivers on both communities, but the plant neighborhood explained less variation in fungal endophytes than expected. Overall, these findings suggest a more cosmopolitan distribution of bacterial OTUs compared to fungal OTUs, a structuring role of the plant host species for both communities, and largely similar effects of the plant neighborhood, abiotic drivers, and space on both communities. 

Abstract Coastal systems are immensely valuable to humans. They contain unique ecosystems that are biodiversity reservoirs and provide key ecosystem services as well as a wealth of cultural heritage. Despite their importance to humans, many coastal systems are experiencing degradation that threatens their integrity and provisioning of services. While much is known about the plant communities and associated wildlife in coastal areas, the importance of microorganisms represents a large knowledge gap. Here we review the ecology of plant-microbial symbioses in coastal systems, including mycorrhizae, nitrogen fixers, endophytes, rhizosphere microbes, and pathogens. We focus on four common coastal communities: sand dunes, marshes, mangroves, and forests/shrublands. We also assess recent research and the potential for using microbes in coastal restoration efforts to mitigate anthropogenic impacts. We find that microbial symbionts are largely responsible for the health of plants constituting the foundation of coastal communities by affecting plant establishment, growth, competitive ability, and stress tolerance, as well as modulating biogeochemical cycling in these stressful coastal systems. Current use of microbial symbionts to augment restoration of stressful and degraded coastal systems is still very much in its infancy; however, it holds great promise for increasing restoration success on the coast. Much research is still needed to test and develop microbial inocula for facilitating restoration of different coastal systems. This is an excellent opportunity for collaboration between restoration practitioners and microbial ecologists to work toward a common goal of enhancing resilience of our coastal ecosystems at a time when these systems are vulnerable to an increasing number of threats.