Search

Contrary to their terrestrial counterparts, freshwater plants are linked to flooding dynamics associated with their habitats in or around water. Gas diffusivity, light availability, nutrient concentrations, and flow velocity select not only on freshwater eco-physiological adaptive traits but also on general plant functional traits, such as plant height or specific leaf area. Emerging stressors under global change impact freshwater plant functions at different temporal and spatial scales via both trait–trait and trait–environment relationships. Predicting how freshwater plant communities are changing and the reciprocal relationships between freshwater plant functions and the environment will require a focus on the specific conditions and traits important for a life in water. Freshwater ecosystems are of worldwide importance for maintaining biodiversity and sustaining the provision of a myriad of ecosystem services to modern societies. Plants, one of the most important components of these ecosystems, are key to water nutrient removal, carbon storage, and food provision. Understanding how the functional connection between freshwater plants and ecosystems is affected by global change will be key to our ability to predict future changes in freshwater systems. Here, we synthesize global plant responses, adaptations, and feedbacks to present-day and future freshwater environments through trait-based approaches, from single individuals to entire communities. We outline the transdisciplinary knowledge benchmarks needed to further understand freshwater plant biodiversity and the fundamental services they provide. [ABSTRACT FROM AUTHOR]

Background and Aims While trait-based approaches have provided critical insights into general plant functioning, we lack a comprehensive quantitative view on plant strategies in flooded conditions. Plants adapted to flooded conditions have specific traits (e.g. root porosity, low root/shoot ratio and shoot elongation) to cope with the environmental stressors including anoxic sediments, and the subsequent presence of phytotoxic compounds. In flooded habitats, plants also respond to potential nutrient and light limitations, e.g. through the expression of leaf economics traits and size-related traits, respectively. However, we do not know whether and how these trait dimensions are connected. Methods Based on a trait dataset compiled on 131 plant species from 141 studies in flooded habitats, we quantitatively analysed how flooding-induced traits are positioned in relation to the other two dominant trait dimensions: leaf economics traits and size-related traits. We evaluated how these key trait components are expressed along wetness gradients, across habitat types and among plant life forms. Key Results We found that flooding-induced traits constitute a trait dimension independent from leaf economics traits and size-related traits, indicating that there is no generic trade-off associated with flooding adaptations. Moreover, individual flooding-induced traits themselves are to a large extent decoupled from each other. These results suggest that adaptation to stressful environments, such as flooding, can be stressor specific without generic adverse effects on plant functioning (e.g. causing trade-offs on leaf economics traits). Conclusions The trait expression across multiple dimensions promotes plant adaptations and coexistence across multifaceted flooded environments. The decoupled trait dimensions, as related to different environmental drivers, also explain why ecosystem functioning (including, for example, methane emissions) are species and habitat specific. Thus, our results provide a backbone for applying trait-based approaches in wetland ecology by considering flooding-induced traits as an independent trait dimension. [ABSTRACT FROM AUTHOR]

Plants have developed a suite of traits to survive the anaerobic and anoxic soil conditions in wetlands. Previous studies on wetland plant adaptive traits have focused mainly on physiological aspects under experimental conditions, or compared the trait expression of the local species pool. Thus, a comprehensive analysis of potential factors driving wetland plant adaptive traits under natural environmental conditions is still missing.In this study, we analysed three important wetland adaptive traits, that is root porosity, root/shoot ratio and underwater photosynthetic rate, to explore driving factors using a newly compiled dataset of wetland plants. Based on 21 studies at 38 sites across different biomes, we found that root porosity was affected by an interaction of temperature and hydrological regime; root:shoot ratio was affected by temperature, precipitation and habitat type; and underwater photosynthetic rate was affected by precipitation and life‐form. This suggests that a variety of driving mechanisms affect the expression of different adaptive traits.The quantitative relationships we observed between the adaptive traits and their driving factors will be a useful reference for future global methane and denitrification modelling studies. Our results also stress that besides the traditionally emphasized hydrological driving factors, other factors at several spatial scales should also be taken into consideration in the context of future functional wetland ecology. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Wetland plants have developed a suite of traits, such as aerenchyma, radial oxygen loss and leaf gas films, to adapt to the wetland environment characterised by, for example, a low redox potential and a lack of electron acceptors. These ecophysiological traits are critical for the survival and physiological functioning of wetland plants. Most studies on these traits typically focus on a single trait and a single or few species at the time.Next to these traits, traits of the leaf economics spectrum (LES) that reflect resource acquisition and allocation in plant species have also been frequently measured in wetlands. However, the performance of the LES has rarely been examined among wetland plants.Both suites of traits are critical for—but affect different aspects of—wetland plant functioning and survival. The interactions between them, potentially causing synergies or trade‐offs, reflect wetland plant strategies to simultaneously deal with stress tolerance and resource utilization, and have ramifications for the functioning of wetland ecosystems.Based on a literature review and quantitative analysis of available data, we provide evidence suggesting that LES and ecophysiological traits may be decoupled (e.g., for root porosity and radial oxygen loss vs. leaf nitrogen) or coupled (e.g., for iron tolerance vs. specific leaf area) in wetlands, depending on the trait combination concerned. This rather complex relationship between wetland adaptive traits and LES traits indicates that there can be multiple mechanisms behind the strategies of wetland plants.We further illustrate how adaptive and LES traits together contribute to wetland ecosystem functions, such as denitrification and methane emission. We highlight that both suites of traits should be considered simultaneously when applying trait‐based methods to wetland ecology. [ABSTRACT FROM AUTHOR]

Trait-based community assembly analysis, which links the plant traits to the variation of community composition along environmental gradients, has potential to improve the understanding of the impacts of eutrophication on macrophytes and responding process. In this article, we pioneered the use of RLQ and Fourth-Corner methods that establish in a quantitative way the link between macrophyte traits, macrophyte community and water quality in a eutrophic shallow lake, eastern China. A total of 9 environmental variables and 11 macrophyte traits were included in the analysis. We found that total phosphorus in water (25.7%, the contribution to total inertia in RLQ analysis), suspended solids (20.7%), water transparency (17.1%) and Chlorophyll a (14.0%) were the main environmental variables that were associated the macrophyte traits matrix. Among macrophyte traits, life form (15.7%), responded to the environmental conditions the most, followed by leaf nitrogen (13.8%) and specific leaf area (13.6%). The correlation between macrophyte traits and environmental gradients showed that macrophytes with higher leaf nitrogen and higher specific leaf area grew at locations with clear water condition, better water transparency and with less total phosphorus, Chlorophyll a and suspended solids in this shallow eutrophic lake. The results suggested that the leaf nitrogen and specific leaf area of macrophytes had a trend to decrease with the increasing environmental stresses caused by eutrophication. Moreover, we highlighted that total phosphorus in water should be prior considered for the future macrophyte conservation and restoration in this lake. [ABSTRACT FROM AUTHOR]

Environmental factors impact species richness differently across taxonomic groups, and understanding the geographic patterns and drivers influencing alpine plant richness remains limited. This study compiled global distribution data of 404 species of Gentiana, an alpine genus, and analyzed the relative effects of different environmental factors and several previously proposed models on the variation of Gentiana richness. By evaluating the effects of range size and regions on the relationships between Gentiana richness and environmental factors, we found that all tested environmental factors had weak effects on richness variation for all species and wide‐ranging species, while habitat heterogeneity was the best predictor for narrow‐ranging species. Habitat heterogeneity was the main driver of richness variation in Europe and Asia, but not in North America. The multiple regression model that included variables for energy, water, seasonality, habitat heterogeneity and past climate change had the highest explanatory power, but it still explained less than 50% of the variation in species richness for all Gentiana species at both global and regional scale, except for Europe. The limited explanatory power of environmental factors in explaining species richness patterns for all species, along with the variations observed among regions, suggest that other factors, such as evolutionary processes and biogeographic history may have also influenced the geographic patterns of Gentiana species richness. In conclusion, our results indicate a limited influence of climate factors on alpine species richness, while habitat heterogeneity, along with its impacts on speciation and dispersal, likely play significant roles in shaping the richness of alpine Gentiana species. [ABSTRACT FROM AUTHOR]

Wetland plants live in habitats which are distinguished from terrestrial ecosystems by their unique characteristics including anoxic conditions, frequent flooding and submergence. To understand how/why they deviate from terrestrial plants, a comprehensive quantitative knowledge of trait selection in wetlands is needed. We built a global database of wetland plant functional traits which includes >8000 observations of >1200 species from >200 references (containing both published and unpublished sources), encompassing leaf economics traits, eco-physiological adaptation traits and also associated environmental data from a variety of wetland habitats around the world. Our database is unique in aiming only at plants living in wetland habitats, and it has not been included in the TRY database yet.Based on our database, we analysed the principal driving factors for wetland adaptation traits. We showed that different drivers affect adaptation traits differently. This suggests that seemingly similar wetland stresses (anoxia, flooding) across a variety of wetland habitats still select for a distinct set of wetland adaptation traits. We also noticed that some of the wetland adaptation traits were statistically decoupled from leaf economics spectrum (LES) traits, which suggests that wetland adaptation traits may not be constrained by the habitat resources/nutrient limitation. This allows wetland plants to survive in complex wetland ecosystems under varied hydrological regimes and fertility status. We also found trade-offs between some of the adaptation traits and LES traits, which suggests that plants need to optimize the allocation of resources between survival and growth for certain environmental stresses. The fact that no clear leading dimension was detected for wetland adaption traits emphasizes the complex character of wetland ecosystems.Our database will provide the backbone for quantitatively understanding the wetland plant species' adaptation strategy, distribution and their link to ecosystem functioning such as the carbon and nitrogen cycles for future studies at a global scale. [ABSTRACT FROM AUTHOR]

Functional biogeography has advanced the field of functional ecology into a more spatially predictive science. However, freshwater plants are still underrepresented in these trait based advancements. Here, we argue that there is a need for developing a functional biogeographical framework for freshwater plants and initiate global mapping efforts focusing on the form and function of freshwater plants. Specific attention should be given to (1) the placement of freshwater plants in the global plant trait space and show how this placement links to global trait environment relationships; (2) the theoretical framework for major structural trait trait correlations based on the physical constraints in aquatic ecosystems; (3) the evolutionary and environmental drivers underlying the global distribution of inter and intra specific variation in different life forms; and (4) the level of equilibrium between spatial and temporal trait environment relationships in freshwater plants. By putting freshwater plants in the context of these spatial aspects, we could advance our understanding of freshwater plant adaptations and responses to environmental gradients, and thereby facilitate predicting the consequences of global changes for freshwater ecosystem functions and services. [Display omitted] • Freshwater plants have been underexamined in the context of functional biogeography. • Global mapping efforts focusing on their form and function are needed. • This will help advance our understanding of freshwater plant unique adaptations. • Such an exercise will be accomplished by the MAP Project (www.lifeinmud.com/map). • We are recruiting collaborators from around the world, starting in late 2021. [ABSTRACT FROM AUTHOR]

The circular construction hub is a logistics point for the storage, processing, and distribution of secondary construction materials. However, its site selection is dampened by the lack of detailed spatial information on material flows. In this study, the quantities and the spatial distribution of material flows are projected using a bottom-up building stock model. The material flows are integrated with logistics networks to assess the environmental impact of transporting materials between the building stock and the circular construction hub. The model is demonstrated on the building stock of Leiden, a municipality in the Netherlands. The results show that the location of future construction and demolition activities has a major impact on transportation carbon emissions. As construction decreases and demolition increases, the relative share of transportation carbon emissions from recycling will increase. The comparison between the two candidate sites for the circular construction hub is made to select the site with lower total transportation carbon emissions. By considering the evolution of building stock, the model can help urban planners make a more comprehensive decision on the location of the circular construction hub. •The quantities and spatial distribution of building material flows are projected using a bottom-up building stock model. •Both forward and reverse logistics networks are considered to account for the transportation carbon emissions of secondary materials. •The location of future construction and demolition activities has a major impact on transportation carbon emissions. •The relative share of transportation carbon emissions from demolition waste recycling may increase due to the reduction in annual new construction. [ABSTRACT FROM AUTHOR]

Water eutrophication creates unfavorable environmental conditions for submerged macrophytes. In these situations, biotic interactions may be particularly important for explaining and predicting the submerged macrophytes occurrence. Here, we evaluate the roles of biotic interactions in predicting spatial occurrence of submerged macrophytes in 1959 and 2009 for Dianshan Lake in eastern China, which became eutrophic since the 1980s. For the four common species occurred in 1959 and 2009, null species distribution models based on abiotic variables and full models based on both abiotic and biotic variables were developed using generalized linear model ( GLM) and boosted regression trees ( BRT) to determine whether the biotic variables improved the model performance. Hierarchical Bayesian-based joint species distribution models capable of detecting paired biotic interactions were established for each species in both periods to evaluate the changes in the biotic interactions. In most of the GLM and BRT models, the full models showed better performance than the null models in predicting the species presence/absence, and the relative importance of the biotic variables in the full models increased from less than 50% in 1959 to more than 50% in 2009 for each species. Moreover, co-occurrence correlation of each paired species interaction was higher in 2009 than that in 1959. The findings suggest biotic interactions that tend to be positive play more important roles in the spatial distribution of multispecies assemblages of macrophytes and should be included in prediction models to improve prediction accuracy when forecasting macrophytes' distribution under eutrophication stress. [ABSTRACT FROM AUTHOR]