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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. 

Tropical mountain ecosystems hold immense ecological and economic importance, yet they face disproportionate risks from shifting tropical climates. For example, present-day montane vegetation of East Africa is characterized by different plant species that grow in and are restricted to certain elevations due to environmental tolerances. As climate changes and temperature/rainfall zones move on mountains, these species must rapidly adjust their ranges or risk extinction. Paleoenvironmental records offer valuable insights into past climate and ecosystem dynamics, aiding predictions for ongoing climate change impacts. In particular, warming and wetting in tropical East Africa during the mid-Holocene resulted in both lowland and highland forest expansion. However, the relative impacts of rainfall and temperature change on montane ecosystems along with the influence of lowland forest expansion on montane communities is not completely understood. We use fossil pollen to study the vegetation changes in two lakes at different altitudes in the Rwenzori Mountains, Uganda: Lake Mahoma (Montane Forest belt) and Upper Kachope Lake (Afroalpine belt). Further, using the newly relaunched African Pollen Database and recent temperature reconstructions, we provide a regional synthesis of vegetation changes in the Rwenzori and then compare this with changes observed from other equatorial East African montane sites (particularly Mt Kenya). In the early to mid-Holocene in the Rwenzori Mountains, trees common today in lowland forests dominated, driven largely by warmer temperatures. After 4000 years ago (4ka), Afromontane forest trees along with grasses progressively replaced lowland trees. Not all sites experienced identical transitions. For instance, at Lake Rutundu on Mt Kenya at the same elevation as Lake Mahoma, bamboo expansion preceded Afromontane forest growth, likely influenced by variations in fire. Variance partitioning indicates that each site responded differently to changes in temperature and rainfall. Therefore, these site-specific ecological responses underscore the importance of considering biogeographic legacies as management strategies are developed, despite similarities in modern ecology.