Plant Functional Diversity Research Articles

Woody plant taxonomic, functional, and phylogenetic diversity decrease along elevational gradients in Andean tropical montane forests: Environmental filtering and arrival of temperate taxa

Mountains are paramount for exploring biodiversity patterns due to the mosaic of topographies and climates encompassed over short distances. Biodiversity research has traditionally focused on taxonomic diversity when investigating changes along elevational gradients, but other facets should be considered. For first time, we simultaneously assessed elevational trends in taxonomic, functional, and phylogenetic diversity of woody plants in Andean tropical montane forests and explored their underlying ecological and evolutionary causes. This investigation covered four transects (traversing ca. 2200 m a.s.l.) encompassing 114 plots of 0.1 ha across a broad latitudinal range (ca. 10°). Using Hill numbers to quantify abundance-based diversity among 37,869 individuals we observed a consistent decrease in taxonomic, functional, and phylogenetic diversity as elevation increased, although the decrease was less pronounced for higher Hill orders. The exception was a slight increase in phylogenetic diversity when dominant species were over-weighted. The decrease in taxonomic and functional diversity might be attributed to an environmental filtering process towards highlands, where the increasingly harsher conditions exclude species and functional strategies. Besides, the differences in steepness decrease between Hill orders suggest that rare species disproportionately contribute to functional diversity. For phylogenetic diversity the shifting elevational trend between Hill orders indicates a greater than previously considered influence in central Andean highlands of tropical lowlands originated species with strong niche conservatism relative to distantly related temperate lineages. This could be explained by a decreasing presence and abundance of temperate, extratropical taxa towards the central Andes relative to northern or southern Andes, where they are more prevalent.

Geographic patterns and environmental correlates of taxonomic, phylogenetic and functional β-diversity of wetland plants in the Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau (QTP) harbours the largest wetland complex in China, with a relatively high diversity of wetland plants. While there has been extensive research on the α-diversity of various plant groups in the QTP, the study of β-diversity specifically in wetland plants has been limited. In this study, we quantified the geographic pattern of wetland plant β-diversity from three dimensions: taxonomic, phylogenetic, and functional. We assessed the relative importance of geographic distance, climatic distance, environmental distance and topographic distance on the pattern of β-diversity. The results indicate a high consistency in the geographic pattern of wetland plant β-diversity across the three dimensions. β-diversity is high in the mountainous regions at the edge of the plateau and relatively low in the plateau platform. The turnover component contributes more to taxonomic β-diversity than nestedness, whereas the opposite is true for phylogenetic and functional β-diversity. Furthermore, taxonomic β-diversity is higher than phylogenetic and functional β-diversity. The geographic patterns of taxonomic, phylogenetic and functional diversity of wetland plants in the QTP are jointly influenced by environmental filtering and dispersal limitation. Climatic variables (temperature seasonality, annual precipitation, precipitation seasonality and annual mean temperature) and topographic variables (elevation variation coefficient, elevation and slope) were identified as the main factors influencing wetland plant β-diversity in the QTP. Overall, this study contributes to elucidating the evolutionary history and formation mechanisms of wetland plant communities in the QTP, and reveals the large-scale patterns of wetland plant diversity.

Seasonal and habitat dependence of plant species, functional and phylogenetic diversity in agricultural landscapes

The biodiversity of agricultural landscapes is under significant threat, while non-agricultural habitats within these landscapes play a crucial role in biodiversity conservation. There has been limited investigation into how plant species, functional and phylogenetic diversity varies across different seasons and habitats in agricultural landscapes. Thus, we carried out a survey of the plant communities in non-agricultural habitats in China's lower Yellow River plain. We investigated the diversity features of plant functionality, phylogeny, and plant species. We compared differences in plant community structure using non-metric multidimensional scaling analysis and tested phylogenetic signal using phylogenetic methods. Our analysis of plant community and diversity characteristics revealed significant differences in plant community structure between seasons and habitats, with the season having a more significant impact. The levels of plant species, functional, and phylogenetic diversity followed a seasonal pattern, with spring seeing the highest values and autumn seeing the lowest. Woodland and hedgerow habitats had the highest levels of diversity, while field roads had the lowest. The community phylogenetic structure of non-agricultural habitats was relatively concentrated and mainly influenced by human interference and environmental filtering. These findings offer scientific support for the preservation of ecosystem services and biodiversity in agricultural landscapes.

The effects of co-invasion by three Asteraceae invasive alien species on plant taxonomic and functional diversity in herbaceous ruderal communities in southern Jiangsu, China.

Invasive alien species can affect plant taxonomic and functional diversity. Multiple invasive alien species can co-invade the same plant community. However, the effects of such co-invasion on plant taxonomic and functional diversity are currently unclear. Our study aimed to estimate the effects of co-invasion by three Asteraceae invasive alien species (i.e., Conyza canadensis (L.) Cronquist, Conyza sumatrensis (S.F. Blake) Pruski and G. Sancho, and Solidago canadensis L.) on plant taxonomic and functional diversity in herbaceous ruderal communities in southern Jiangsu, China. The effects of these three invasive alien species under seven invasion combinations (including invasion by one invasive alien species, co-invasion by two invasive alien species, and co-invasion by these three invasive alien species) on plant taxonomic and functional diversity were investigated in a comparative field study of herbaceous ruderal communities. Niche differentiation mediated the functional divergence between these three invasive alien species and natives under all invasion combinations. These three invasive alien species significantly increased plant taxonomic diversity (especially plant diversity and richness) and plant functional diversity (especially Rao's quadratic entropies) under all invasion combinations. The relative abundance of invasive alien species was significantly positively associated with plant functional diversity (especially community-weighted mean trait values and Rao's quadratic entropy). The number of invasive alien species was significantly positively associated with plant taxonomic diversity (especially plant diversity and richness) and plant functional diversity (especially Rao's quadratic entropies). Thus, co-invasion by these three invasive alien species may synergistically increase plant taxonomic diversity (especially plant diversity and richness) and functional diversity (especially Rao's quadratic entropies).

Drivers of plant diversity, community composition, functional traits, and soil processes along an alpine gradient in the central Chilean Andes.

High alpine regions are threatened but understudied ecosystems that harbor diverse endemic species, making them an important biome for testing the role of environmental factors in driving functional trait-mediated community assembly processes. We tested the hypothesis that plant community assembly along a climatic and elevation gradient is influenced by shifts in habitat suitability, which drive plant functional, phylogenetic, and spectral diversity. In a high mountain system (2400-3500 m) Región Metropolitana in the central Chilean Andes (33°S, 70°W). We surveyed vegetation and spectroscopic reflectance (400-2400 nm) to quantify taxonomic, phylogenetic, functional, and spectral diversity at five sites from 2400 to 3500 m elevation. We characterized soil attributes and processes by measuring water content, carbon and nitrogen, and net nitrogen mineralization rates. At high elevation, colder temperatures reduced available soil nitrogen, while at warmer, lower elevations, soil moisture was lower. Metrics of taxonomic, functional, and spectral alpha diversity peaked at mid-elevations, while phylogenetic species richness was highest at low elevation. Leaf nitrogen increased with elevation at the community level and within individual species, consistent with global patterns of increasing leaf nitrogen with colder temperatures. The increase in leaf nitrogen, coupled with shifts in taxonomic and functional diversity associated with turnover in lineages, indicate that the ability to acquire and retain nitrogen in colder temperatures may be important in plant community assembly in this range. Such environmental filters have important implications for forecasting shifts in alpine plant communities under a warming climate.

Invasive earthworms can change understory plant community traits and reduce plant functional diversity

Among the most important impacts of biological invasions on biodiversity is biotic homogenization, which may further compromise key ecosystem processes. However, the extent to which they homogenize functional diversity and shift dominant ecological strategies of invaded communities remains uncertain. Here, we investigated changes in plant communities in a northern North American forest in response to invasive earthworms, by examining the taxonomic and functional diversity of the plant community and soil ecosystem functions. We found that although plant taxonomic diversity did not change in response to invasive earthworms, they modified the dominance structure of plant functional groups. Invasive earthworms promoted the dominance of fast-growing plants at the expense of slow-growing ones. Moreover, earthworms decreased plant functional diversity, which coincided with changes in abiotic and biotic soil properties. Our study reveals that invasive earthworms erode multiple biodiversity facets of invaded forests, with potential cascading effects on ecosystem functioning.

Soil nutrients determine leaf traits and above-ground biomass in the tropical cloud forest of Hainan Island

Identifying soil characteristics associated with the plant’s resource use and acquisition strategy at different scales could be a crucial step to understanding community assembly and plant strategy. There is an increasing trend that plant functional properties can be an important driver of ecosystem functioning. However, major knowledge gaps exist about how soil abiotic properties, shape species diversity, above-ground biomass (AGB) and plant functional diversity in the Bawangling tropical forest (TCF) of Hainan island. Hence we hypothesized that plant functional traits and above-ground biomass would be strongly associated with soil abiotic factors given their direct relationship to soil resource acquisition and use. Here, we used 12 plant functional traits (FTs), above-ground biomass (AGB), and five soil nutrients in the Bawangling tropical cloud forest of Hainan Island by using a polynomial regression model and multivariate correlations to show relationship and identify how plants allocate their limited resources to adapt to their surroundings. Various phytosociological attributes were assessed and an Importance Value Index (IVI) value was calculated for each species to determine the dominant species. More than half of the total variations could be attributed to interspecific variations in H, DBH, LA, LMA, and LDW. From a taxonomic perspective; we found that species-level variance was more significant for plant functional traits and soil nutrients like TN, AP, TP, and OM. On the other hand, variation in specific stem density (SSD), leaf thickness (LT), leaf phosphorus (LP) and leaf soluble sugar (LS) was an exception for these tendencies. Among soil nutrients, soil nitrogen and phosphorus significantly impact the species and functional traits. Furthermore, the soil AN and TP we also found to have a comparatively strong positive relationship with above-ground biomass (AGB) as compared with other soil nutrients. The morpho-physiological functional traits showed a trade-off between conservative and acquisitive resource usage. These variations suggested that the relationships of functional traits, AGB, and species with soil nutrients mainly AN and TP in tropical cloud forests can directly affect the growth, reproduction, and survival of the species and are beneficial for the species co-existence and maintenance of biodiversity.

Navigating uncertainty: Managing herbivore communities enhances Savanna ecosystem resilience under climate change

Abstract Savannas are characterized by water scarcity and degradation, making them highly vulnerable to increased uncertainties in water availability resulting from climate change. This poses a significant threat to ecosystem services and rural livelihoods that depend on them. In addition, the lack of consensus among climate models on precipitation change makes it difficult for land managers to plan for the future. Therefore, Savanna rangeland management needs to develop strategies that can sustain Savanna resilience and avoid tipping points under an uncertain future climate. Our study aims to analyse the impacts of climate change and rangeland management on degradation in Savanna ecosystems of southern Africa, providing insights for the management of semi‐arid Savannas under uncertain conditions worldwide. To achieve this, we simulated the effects of projected changes in temperature and precipitation, as predicted by 10 global climate models, on water resources and vegetation (cover, functional diversity, tipping points (transition from grass‐dominated to shrub‐dominated vegetation)). We simulated three different rangeland management options (herbivore communities dominated by grazers, by browser and by mixed feeders), each with low and high animal densities, using the ecohydrological model EcoHyD. Our results identified intensive grazing as the primary contributor to the increased risk of degradation in response to changing climatic conditions across all climate change scenarios. This degradation encompassed a reduction in available water for plant growth within the context of predicted climate change. It also entails a decline in the overall vegetation cover, the loss of functionally important plant species and the inefficient utilization of available water resources, leading to earlier tipping points. Synthesis and applications. Our findings underscore that, in the face of climate uncertainty, farmers' most effective strategy for securing their livelihoods and ecosystem stability is to integrate browsers and apply management of mixed herbivore communities. This management approach not only significantly delays or averts tipping points but also maintained greater plant functional diversity, fostering a more robust and resilient ecosystem that acts as a vital buffer against adverse climatic conditions.

Linkages between plant functional diversity and soil-based ecosystem services in urban and peri-urban vacant lots

Linkages between plant functional diversity and soil-based ecosystem services in urban and peri-urban vacant lots

Mapping functional diversity of canopy physiological traits using UAS imaging spectroscopy

Plant functional diversity (FD) is a component of biodiversity linking plant functional traits to ecosystem processes (e.g., photosynthesis) and services (e.g., gross primary production). Development of remote sensing capabilities to monitor forest FD across various spatio-temporal scales is critical, especially in view of increasing global climate and anthropogenic pressures. Here, we focus on investigating the capability of unoccupied aerial systems (UAS), acquiring imaging spectroscopy data of high spatial (pixel size ≤0.1 m) and spectral (band-width < 5 nm between 400 and 1000 nm) resolutions, to map two trait-based FD metrics, namely, richness and divergence, of two open sclerophyll forests at the plot-scale (<0.2 km2). An emerging scalable kernel-based trait probability density (TPD) approach was implemented to compute spatially explicit metrics of FD at different areal extents and pixel sizes through spatially resampled products. Narrow-band spectral indices were utilized as proxies of selected plant functional traits, including photoprotective zeaxanthin-to-antheraxanthin transformation ratio (VAZ), and foliar pigments of chlorophylls and anthocyanins (Cab and Cant). The combination of high-resolution imagery and TPDs presents a suitable alternative to the traditional need for taxonomic information and alleviates pixel-based spectral mixing issues known to affect pixel-based FD metrics. A moving kernel (6 × 6 m) applied to UAS data, allowed to capture fine and medium-scale drivers of functional richness and divergence, including within-crown and complex branching variance, topography, sun aspect, and speciation. For the same kernel size, functional richness computed from coarsened pseudo-airborne products (pixel size of 2 m) was found to be 57–68% of that derived from UAS products. Functional divergence did not portray substantial differences across scales and resolutions, even though this metric further emphasized the complexity of the surveyed open-forest sclerophyll sites. UAS have the potential to become an efficient tool for monitoring FD linked with ecosystem processes at key monitoring sites, and for the validation and support of large-scale but less detailed airborne and satellite products. Finally, this study highlights the sensitivity of FD metrics to variations in scale, resolution, and TPD parametrization suggesting that more research is needed to standardize remote sensing protocols for the quantification of FD across spatial and temporal scales.

Soil and plant attributes under grazing exclusion in semi-steppic semi-arid rangelands, Iran

The aim of this study was to investigate the effect of exclusion (20 years) on the attributes of soil and vegetation in northwest of Iran. Three sites in grazed and three sites in exclusion areas were selected. At each site, three 100 m transects were established for sampling purposes. Soil attributes, including electrical conductivity, pH, calcium carbonate, organic carbon, nitrogen, phosphorus, potassium, clay, silt, calcium, magnesium, and bicarbonate were measured in the lab. Additionally, the primary and secondary attributes of vegetation including density, canopy cover, aboveground net primary production (ANPP) of plant functional types (PFTs), diversity, richness and evenness indices were recorded. The findings of our study indicate that the exclusion site exhibited significantly higher levels of soil organic carbon (1.91%), total nitrogen (0.95%), available phosphorus (1.75 ppm), and soluble potassium (163.52 ppm) compared to the grazed site. However, no significant differences were observed in other soil characteristics between the two sites. Density, canopy cover percentage, ANPP of PFTs (p < .01), diversity (1.92), and richness index (9.64), were higher in the exclusion area (p < .05), while, evenness showed no significant difference. The total species density and canopy cover within the exclusion area were also found to be higher than in grazed areas. Results suggest that exclusion in semi-arid semi-steppes plays an important role in rangeland management.

Along the river: Longitudinal patterns of functional and taxonomic diversity of plants in riparian forests

AbstractQuestionsThe River Continuum Concept (RCC) predicts a gradual shift of functional adaptations of organisms along the longitudinal (upstream–downstream) gradient, as well as the maximization of the biotic diversity in mid‐reaches. Although this theoretical framework was originally developed for stream macroinvertebrates, we tested whether such a pattern can also be observed in riparian plant communities.LocationThe study was conducted in the upper catchments of the San and Wisłoka Rivers in southeastern Poland. In both catchments, very well preserved riparian forests occur continuously along both rivers.MethodsWe studied the cover of plant species in riparian forests across two river networks. We analyzed the taxonomic and functional diversity indices, as well as community‐weighted means of functional traits in relation to the plots' positions in the catchments.ResultsThe functional richness and divergence displayed unimodal patterns of increasing values in the mid‐reaches. The patterns of taxonomic diversity were similar, but some plots in the lowest reaches were more diverse than expected, forming an additional increase in diversity. The observed patterns were largely in line with the predictions of RCC. We discovered a significant decrease in the specific leaf area and an increase in the height of herbaceous plants in communities along a longitudinal gradient. There was also a shift in the dispersal syndromes, toward a higher importance of zoochory in the lower reaches.ConclusionsThe study shows that plant communities in natural riparian forests show continuous species turnover along the longitudinal gradient that, along with the longitudinal shift of abiotic factors, creates patterns that are known from theoretical predictions.

Nitrogen availability and plant functional composition modify biodiversity-multifunctionality relationships.

Biodiversity typically increases multiple ecosystem functions simultaneously (multifunctionality) but variation in the strength and direction of biodiversity effects between studies suggests context dependency. To determine how different factors modulate the diversity effect on multifunctionality, we established a large grassland experiment manipulating plant species richness, resource addition, functional composition (exploitative vs. conservative species), functional diversity and enemy abundance. We measured ten above- and belowground functions and calculated ecosystem multifunctionality. Species richness and functional diversity both increased multifunctionality, but their effects were context dependent. Richness increased multifunctionality when communities were assembled with fast-growing species. This was because slow species were more redundant in their functional effects, whereas different fast species promoted different functions. Functional diversity also increased multifunctionality but this effect was dampened by nitrogen enrichment and enemy presence. Our study suggests that a shift towards fast-growing communities will not only alter ecosystem functioning but also the strength of biodiversity-functioning relationships.

Multidimensional trait variability in a widespread, Paleoarctic macrophyte: functional, spectral and genetic drivers

Understanding how environmental conditions and plant functional variation are mutually related is critical to improving our comprehension of plant adaptations. In this context, our knowledge of the interlinks between plant functional, spectral and genetic traits and environmental filters is still very limited, especially for wetland species. To gain new insights on this topic, a multidimensional dataset, centred on the widespread macrophyte species Nuphar lutea, was assembled by collecting data on functional traits (including spectral traits), genetic metrics and environmental determinants from 28 plots spanning north‐central Italy. A strong environmental filter acts on all traits (morphological, biochemical, spectral and the genetic diversity metrics) resulting in significant local control over trait patterns, exemplified by the discrimination value of water electrical conductivity. This is further reinforced by the key contribution of sediment variables in explaining traits variation. Site‐specific environmental conditions were reflected in different patterns of genetic diversity, suggesting a long‐term effect of environmental filters on genotypes as well. High water conductivity – in our study sites indicative of long‐term hydrogeological settings – is linked to more acquisitive behaviour in N. lutea and a progressive reduction in its genetic diversity, while high nutrients availability in sediments promotes higher leaf traits performance. This study better explores how high variability in leaf traits reinforces current genetic and mechanistic knowledge about competitive strategies in the key aquatic plant N. lutea, by testing the effectiveness of a novel integrative approach to assess multiple sources of plant functional variation.

Plant-soil synchrony in nutrient cycles: Learning from ecosystems to design sustainable agrosystems.

Redesigning agrosystems to include more ecological regulations can help feed a growing human population, preserve soils for future productivity, limit dependency on synthetic fertilizers, and reduce agriculture contribution to global changes such as eutrophication and warming. However, guidelines for redesigning cropping systems from natural systems to make them more sustainable remain limited. Synthetizing the knowledge on biogeochemical cycles in natural ecosystems, we outline four ecological systems that synchronize the supply of soluble nutrients by soil biota with the fluctuating nutrient demand of plants. This synchrony limits deficiencies and excesses of soluble nutrients, which usually penalize both production and regulating services of agrosystems such as nutrient retention and soil carbon storage. In the ecological systems outlined, synchrony emerges from plant-soil and plant-plant interactions, eco-physiological processes, soil physicochemical processes, and the dynamics of various nutrient reservoirs, including soil organic matter, soil minerals, atmosphere, and a common market. We discuss the relative importance of these ecological systems in regulating nutrient cycles depending on the pedoclimatic context and on the functional diversity of plants and microbes. We offer ideas about how these systems could be stimulated within agrosystems to improve their sustainability. A review of the latest advances in agronomy shows that some of the practices suggested to promote synchrony (e.g., reduced tillage, rotation with perennial plant cover, crop diversification) have already been tested and shown to be effective in reducing nutrient losses, fertilizer use, and N2 O emissions and/or improving biomass production and soil carbon storage. Our framework also highlights new management strategies and defines the conditions for the success of these nature-based practices allowing for site-specific modifications. This new synthetized knowledge should help practitioners to improve the long-term productivity of agrosystems while reducing the negative impact of agriculture on the environment and the climate.

Ecosystem Resilience of a South African Mesic Grassland with Change from Rotational to Continuous Grazing.

Grazing practices affect the soil and vegetation of grasslands, which further influence the provision of ecosystem services and the productivity of grasslands. We determined the ecosystem resilience of a mesic grassland under three grazing management systems in the Pakkies area, (30°33'08''S, 29°25'22'' E), South Africa: cooperative (continuously grazed since 2017), commercial (rotationally grazed for >20 years), and communal (continuously grazed for >20 years) farms. This was carried out by measuring the penetration resistance and infiltration, soil nutrients, forage quality contents for livestock, veld condition, plant species composition and richness, and functional diversity. The soils had a higher penetration resistance in the continuously grazed communal farm, while water infiltration was highest in the continuously grazed cooperative farm. The plant species and functional diversity were greater in the rotationally grazed commercial farm than in the continuously grazed communal and cooperative farms. The continuously grazed cooperative farm had the highest veld condition score (97%), while the rotationally grazed commercial and the continuously grazed communal farms had 82% and 56% veld condition scores, respectively. The forage quality and soil nutrients were generally similar among all farms. The lower plant diversity observed with continuous grazing may indicate that the ecological system was not as resilient concerning this type of grazing. However, for forage quality, soil nutrients and veld condition, continuous grazing was resilient, which indicates that rotational grazing may not be better than continuous grazing for livestock production in this specific region. As long as a minimum level of ecological resilience can be retained, continuous grazing can sustain effective animal production, particularly for small-holder farmers.

Plant functional, biogeographical and phylogenetic diversity are related to native and non-native plant abundance in invaded Hawaiian forests

Plant functional, biogeographical and phylogenetic diversity are related to native and non-native plant abundance in invaded Hawaiian forests

Urbanization drives divergence in functional diversity and composition of woody plant communities in remnant forest patches

Urbanization has a profound impact on the ecological processes and plant diversity of remnant forests. To understand the relationship between urbanization and woody plant communities in remnant forests, we conducted a study in Guiyang, China, where we sampled 120 plots in 15 remnant forest patches along an urbanization gradient. We evaluated the functional diversity of woody plants based on four functional diversity indices and nine functional traits. We compared the functional diversity among different types of woody plants and between interior and edge communities, and analyzed the changes in functional diversity and individual functional traits along the urbanization gradient. Our results indicate that urbanization significantly decreases the functional diversity of woody plant communities. Additionally, urbanization leads to shifts in functional composition, particularly in shrub species, with an increase in leaf N content and a decrease in leaf C content, leaf C/N ratio, seed germination rate and seed mass. These findings suggest that increasing urbanization reduces the values of high resource-conserving traits of woody plants in remnant forests. Therefore, it is crucial to limit additional urban expansion around remnant forest patches to protect the functional diversity and crucial plant species with strong resource-conserving traits.

Promoting effects of soil C and N and limiting effect of soil P jointly determine the plant diversity during the aerial seeding restoration process in Mu Us sandy land, China.

Exploring the change and maintaining mechanism of plant diversity is of great significance for guiding the restoration of degraded ecosystems. However, how plant taxonomic, functional, and phylogenetic diversity change during long-term ecosystem restoration process and their driving factors remain unclear. Based on the 35-year time gradient of aerial seeding restoration in Mu Us sandy land, this study explored the changes in plant taxonomic, functional, and phylogenetic diversity and the driving factors. The results showed that plant taxonomic, functional, and phylogenetic diversity showed consistent response with the aerial seeding restoration, all of which increased first and then tended to a saturation state in the middle of restoration (14 years). TN, TOC, and NO3 --N increased with aerial seeding restoration and showed a significant positive correlation with plant diversity of the three dimensions, while AP showed a negative correlation. Soil nitrogen and carbon promoted the increase of diversity of three dimensions in the early restoration period, while phosphorus limited the increase of diversity of three dimensions in the middle and late restoration periods. The diversity of three dimensions was mainly affected by restoration time, soil nutrients, and climate factors, and the coupling effect of restoration time and soil nutrients was dominant. These findings indicate that the plant diversity in different dimensions and soil nutrients are improved by aerial seeding restoration. Our study highlights that aerial seeding restoration mainly improves plant diversity by increasing soil nutrients, and the relative effects of different soil nutrients on plant diversity during restoration are inconsistent.

Flooding Depth and Flooding Duration with the Zonation of Riparian Plant Communities in the Three Gorges Reservoir of China

The hydraulics of flows, especially the flooding process, influence the patterns of riparian plant zonation. Different characteristics of the flooding process should be analyzed to correlate plant zonation with flooding due to their different effect modes. The effects of flooding characteristics on riparian plants have yet to be studied, especially in the field. Thus, two elements of the flow regime, flooding duration and depth, were analyzed in relation to the riparian plants of the Three Gorges Reservoir. The taxonomic indices and the functional diversity of the riparian plants in three seasons in 2019 and the corresponding inundation character were surveyed. Our results showed that the riparian plant diversity and functional diversity varied by season. A significant negative relationship between plant diversity and flooding depth was observed, while flooding duration was not a significant predictor in different seasons. The greater explanatory capacity of flooding depth than that of flooding duration suggests that flooding depth could be a better indicator of the zonation of the riparian vegetation in this area. Concerning the vital component of flow hydraulics, growing opportunities to study flooding depth and strategies that consider both flooding time and flooding depth in a reservoir should be offered, as they will assist in refining process-based river restoration.