Plant Diversity最新文献

•We present 'U.Taxonstand Online', a user-friendly web application for scientific name matching of both plants and animals.•U.Taxonstand Online provides a solution for the users with limited abilities of programming and data mining.•We add several new functions to clean and format the data for R package U.Taxonstand.

Managing invasive species requires identifying the factors that determine alien species invasion success. This study investigates how anthropogenic and biogeographical factors influence alien plant invasion in the Sanyang Wetlands, a human-dominated island system in Wenzhou City, China. Specifically, we analyzed whether human activities (e.g., habitat heterogeneity, proportion of road area, and cultivation) and island characteristics (e.g., island area, isolation) affect the diversity of native and invasive plant species similarly. We also assessed the applicability of the equilibrium theory of island biogeography to invasive plant species diversity and examined how these factors affect invasive plant species with different dispersal syndromes (anemochore, zoochore, and autochore). We found that both invasive and native species richness positively correlate with island area, habitat heterogeneity, and proportion of road area. However, although native species richness was negatively correlated with isolation, invasive species richness was not. The diversity and composition of invasive species with different dispersal syndromes were determined by different variables; for example, the composition and diversity of zoochores was increased by habitat heterogeneity, while anemochore species richness was increased by the proportion of road area, whereas anemochore species composition was influenced by distance to the nearest island. We conclude that habitat fragmentation differentially affects invasive and native plant diversity, aligning with the predictions of the equilibrium theory of island biogeography only for native species but not for invasive species. Our findings indicate that tailoring habitat attributes and regulating human activities could be effective strategies for mitigating the spread of invasive species in fragmented landscapes.

•Three types of Symplocos from the late Oligocene and Miocene of Guangxi showcase the diversity of Symplocos during this time.•Earliest Asian megafossils of Symplocos are from the late Oligocene of Nanning Basin, Guangxi, China.•Fossils and modeling reveal Symplocos was quite diverse and has persisted at low latitudes within Asia since late Oligocene.•Climate probably plays a crucial role in driving the diversification of Symplocos in low latitudes of Asia.

Climate and grazing have a significant effect on vegetation structure and soil organic carbon (SOC) distribution, particularly in mountain ecosystems that are highly susceptible to climate change. However, we lack a systematic understanding of how vegetation structure reacts to long-term grazing disturbances, as well as the processes that influence SOC distribution. This study uses multiple sets of data spanning 20 years from a typical alpine grassland in the Qilian Mountains to investigate the effects of climate and grazing on various root-type grasses as well as the mechanisms that drive SOC distribution. We found that grazing increases the biomass of annual, biennial and perennial taproots while decreasing that of perennial rhizomes. We also found that various root-type grasses have different responses to climate and grazing. Multiple factors jointly control the variation of SOC content (SOCc), and the variation of SOC stock (SOCs) is mainly explained by the interaction between climate and grazing years. Climate and grazing can directly or indirectly affect SOCc through vegetation, and SOCs are mainly dominated by the direct effects of grazing years and grazing gradients. Grazing gradients and root-type grass biomass have a significant effect on SOC, with little effect from climate factors. Therefore, long-term grazing may affect the root-type grass and further affect SOC distribution through differences in nutrient acquisition ability and reproductive pathways. These findings provide important guidance for regulating soil carbon sequestration potential by varying the proportion of different root-type grass in the community via sowing, livestock configuration, or grazing time.

The Indo-Burma Biodiversity Hotspot is renowned for its rich biodiversity, including that of vascular plants. However, the fern diversity and its endemism in this hotspot have not been well understood and so far, the diversity of very few groups of ferns in this region has been explored using combined molecular and morphological approaches. Here, we updated the plastid phylogeny of the Java fern genus Leptochilus with 226 (115% increase of the latest sampling) samples across the distribution range, specifically those of three phylogenetically significant species, Leptochilus ovatus, L. pedunculatus, and L. pothifolius. We also reconstructed the first nuclear phylogeny of the genus based on pgiC gene data. Based on molecular and morphological evidence, we identified three new major clades and six new subclades, redefined three existing species, discovered a number of cryptic species of the genus, and elucidated the evolution of the three most variable characters. Our divergence time analyses and ancestral area reconstruction showed that Leptochilus originated in the Oligocene and diversified from early Miocene and 15 dispersal events from lower to higher latitudes are identified. The evolution of three most important morphological characters is analyzed in a context of the new phylogeny. Our analysis showed that 30 (59% of total 51) species of Leptochilus occur in Indo-Burma hotspot, 24 (80% of the 30 species) of which are endemic to this hotspot. We argue that the Indo-Burma hotspot should be recognized as a diversity hotspot for ferns.

Exploring the worldwide patterns of endemism and the processes that lead to the formation of high-endemism centers is crucial in biogeography. This study examines the geographic distribution and ecological influences on the endemism of liverworts across 390 regions worldwide. We assess phylogenetic endemism and relative phylogenetic endemism in relation to eleven environmental factors, which represent current and Quaternary climate variations, as well as topographic and environmental heterogeneity. Areas with higher endemism in liverworts tend to have higher temperatures, precipitation, and environmental heterogeneity, but lower temperature seasonality and lesser impacts from Quaternary climate changes. Regions exhibiting notably high endemism are predominantly found in tropical Asia, Madagascar, eastern Australia, and the Andes, while those with notably low endemism are generally in temperate Eurasia and North America, parts of Africa, and eastern South America. Centers of neo-endemism are mainly in southern Africa, whereas centers of paleo-endemism are in southern South America, tropical Asia, and New Zealand. Environment variability is a more significant predictor of phylogenetic endemism than current climate conditions, which are themselves more predictive than variables related to Quaternary climate changes. Nevertheless, these three types of explanatory variables combined explain only about one-third of the variance in phylogenetic endemism.

Patterns and drivers of species-genetic diversity correlations (SGDCs) have been broadly examined across taxa and ecosystems and greatly deepen our understanding of how biodiversity is maintained. However, few studies have examined the role of canopy structural heterogeneity, which is a defining feature of forests, in shaping SGDCs. Here, we determine what factors contribute to α- and β-species-genetic diversity correlations (i.e., α- and β-SGDCs) in a Chinese subtropical forest. For this purpose, we used neutral molecular markers to assess genetic variation in almost all adult individuals of the dominant tree species, Lithocarpus xylocarpus, across plots in the Ailaoshan National Natural Reserve. We also quantified microhabitat variation by quantifying canopy structure heterogeneity with airborne laser scanning on 20 1-ha subtropical forest plots. We found that species α-diversity was negatively correlated with genetic α-diversity. Canopy structural heterogeneity was positively correlated with species α-diversity but negatively correlated with genetic α-diversity. These contrasting effects contributed to the formation of a negative α-SGDC. Further, we found that canopy structural heterogeneity increases species α-diversity and decreases genetic α-diversity by reducing the population size of target species. Species β-diversity, in contrast, was positively correlated with genetic β-diversity. Differences in canopy structural heterogeneity between plots had non-linear parallel effects on the two levels of β-diversity, while geographic distance had a relatively weak effect on β-SGDC. Our study indicates that canopy structural heterogeneity simultaneously affects plot-level community species diversity and population genetic diversity, and species and genetic turnover across plots, thus driving α- and β-SGDCs.

The karst forest in southwestern China is characterized by thin soil layers, numerous fissures and holes, resulting in low soil water availability and poor water retention, making it challenging for plant growth and survival. While the relationship between plant functional traits and tree growth performance has been extensively studied, the links between tree seasonal growth and drought-tolerant traits in tree species with different leaf habit remains poorly understood. This study evaluated the associations between four-year averaged rainy season stem diameter growth rate and 17 branch and leaf traits across evergreen and deciduous species in a tropical karst forest in southwest China. The cross-species variations in tree growth rates were related to plant hydraulic traits (e.g., vessel lumen diameter, xylem vessel density, stomatal density, and stomatal size) and leaf anatomical traits (e.g., total leaf thickness, lower/upper epidermis thickness, and spongy thickness). The growth of evergreen trees exhibited lower hydraulic efficiency but greater drought tolerance than deciduous tree, which enabled them to maintain higher persistence under low soil water availability and consequently a relatively longer growing season. In contrast, deciduous species showed no correlation between their functional traits and growth rate. The distinct water use strategies of evergreen and deciduous trees may offer a potential explanation for their co-existence in the tropical karst forests.

Leaf nitrogen (N) and phosphorus (P) levels provide critical strategies for plant adaptions to changing environments. However, it is unclear whether leaf N and P levels of different plant functional groups (e.g., monocots and dicots) respond to environmental gradients in a generalizable pattern. Here, we used a global database of leaf N and P to determine whether monocots and dicots might have evolved contrasting strategies to balance N and P in response to changes in climate and soil nutrient availability. Specifically, we characterized global patterns of leaf N, P and N/P ratio in monocots and dicots, and explored the sensitivity of stoichiometry to environment factors in these plants. Our results indicate that leaf N and P levels responded to environmental factors differently in monocots than in dicots. In dicots, variations of leaf N, P and N/P ratio were significantly correlated to temperature and precipitation. In monocots, leaf N/P ratio was not significantly affected by temperature or precipitation. This indicates that leaf N, P and N/P ratio are less sensitive to environmental dynamics in monocots. We also found that in both monocots and dicots N/P ratios are associated with the availability of soil total P rather than soil total N, indicating that P limitation on plant growth is pervasive globally. In addition, there were significant phylogenetic signals for leaf N (λ = 0.65), P (λ = 0.57) and N/P ratio (λ = 0.46) in dicots, however, only significant phylogenetic signals for leaf P in monocots. Taken together, our findings indicate that monocots exhibit a "conservative" strategy (high stoichiometric homeostasis and weak phylogenetic signals in stoichiometry) to maintain their growth in stressful conditions with lower water and soil nutrients. In contrast, dicots exhibit lower stoichiometric homeostasis in changing environments because of their wide climate-soil niches and significant phylogenetic signals in stoichiometry.

Understanding how and why assemblage dissimilarity changes along spatial gradient is a great challenge in ecology, because answers to these questions depend on the analytical types, dimensions, and components of beta diversity we concerned. To obtain a comprehensive understanding of assemblage dissimilarity and its implications for biodiversity conservation in the Himalayas, we explored the elevational patterns and determinants of beta diversity and its turnover and nestedness components of pairwise and multiple types and taxonomic and phylogenetic dimensions simultaneously. Patterns of beta diversity and their components of different types and dimensions were calculated based on 96 sampling quadrats along an 1800-5400 m elevational gradient. We examined whether and how these patterns differed from random expectations using null models. Furthermore, we used random forest methods to quantify the role of environmental variables representing climate, topography, and human disturbance in determining these patterns. We found that beta diversity and its turnover component, regardless of its types and dimensions, shown a hump-shaped elevational patterns. Both pairwise and multiple phylogenetic beta diversity were remarkably lower than their taxonomic counterpart. These patterns were significantly less than random expectation and were mostly associated with climate variables. In summary, our results suggested that assemblage dissimilarity of seed plants was mostly originate from the replacement of closely related species determined by climate-driven environmental filtering. Accordingly, conservation efforts should better cover elevations with different climate types to maximalize biodiversity conservation, rather than only focus on elevations with highest species richness. Our study demonstrated that comparisons of beta diversity of different types, dimensions, and components could be conductive to consensus on the origin and mechanism of assemblage dissimilarity.