Kun Song

Despite decades of urban expansion, the impulse to cultivate food in cities has not disappeared, it has simply gone informal. Informal urban agricultural practices (IUAP), the spontaneous cultivation of crops in urban green spaces without formal authorization, represent a widespread but largely overlooked form of human–environment interaction. Through large-scale field surveys across 129 county-level cities in China, we show that IUAP occurred in 46.3% of surveyed patches and encompassed 111 crop species, a prevalence far exceeding prior expectations. These practices were most common where precipitation and green space were abundant, but contracted sharply under higher urbanization intensity and declining GDP, suggesting that both ecological opportunity and socioeconomic need shape where informal cultivation persists. IUAP mediates the relationship between environmental conditions and crop richness, positioning informal cultivation as an active driver of urban agrobiodiversity rather than a passive response to it. These findings reframe IUAP as a culturally persistent practice worth accommodating through alternative governance approaches, such as community gardens, to reduce regulatory conflict while preserving the agrobiodiversity it sustains.

Vertical stratification in forests acts as an ecological filter, driving woody plants to evolve specialized survival strategies. Angiosperms, in particular, develop secondary xylem with three interdependent functions—water transport, mechanical support, and storage. Trade‐offs between these functions vary with resource heterogeneity and environmental pressures. Balancing these functions is based on trade‐offs in xylem structure, particularly in the xylem space allocation of vessels, fibers, and parenchyma fractions. However, how plants optimize these trade‐offs along forest vertical strata remains unexplored. Anatomical methods were used to determine the fractions of vessels, fibers, and parenchyma in the secondary xylem of 119 individuals within a multilayered forest in eastern China. Ternary plots and standardized major axis analyses were employed to evaluate variations in trade‐offs between vessel and fiber fractions, and between parenchyma and fiber fractions across different vertical strata. We found that trade‐offs in spatial allocation among cell types occur in all vertical strata. For the fiber—vessel trade‐off, canopy and understory trees followed a similar pattern, but canopy trees consistently maintained a higher vessel fraction. In contrast, the fiber—parenchyma trade‐off was markedly stronger in understory trees. Our results illustrate that forest vertical stratification significantly influences trade‐offs in xylem cell allocation, suggesting functional trade‐offs of xylem depend on forest strata. These findings will help clarify how trees adapt to stresses associated with vertical forest strata.

Urbanization and climate change are rapidly altering large-scale plant distributions and local community compositions, profoundly impacting ecosystem functions and services. However, it remains unclear how life form compositions, one of the key functional biodiversity components, respond jointly to urbanization and climate gradients. Here we investigated the life form compositions of 2,864 naturally regenerated spontaneous plant species across 129 cities in Yunnan province of China, a global biodiversity hotspot with diverse environmental condition. Our results showed perennial herbs (45.0%) predominated in urban ecosystem, followed by annual herbs (29.2%) and woody plants (25.8%). Bayesian hierarchical models revealed that as urban expansion, the proportions of annual herbs rise, while the proportions of both perennial herbs and woody plants decline, indicating urban expansion favors short-lived plants but is detrimental to long-lived plants. Increasing mean annual temperature with a decline in perennial herbs and a concurrent increase in woody plants, suggesting divergent adaptive responses to thermal stress. Our results highlight the complex, divergent responses of plant life forms to urbanization and climate change, emphasizing the need for targeted conservation strategies that consider both the resilience of short-lived species and the vulnerability of long-lived plants.

As a widely disseminated world religion, Buddhism's selection of religious species may profoundly impact candidate species distribution. This study sampled 246 Chinese temples covering diverse regions to investigate the selection modes of Buddhist tree species (BTS) and the alien religion's influence on Chinese indigenous biodiversity and spread. In species selection at the national scale, anthropogenic factors were less important for BTS's taxonomic, phylogenetic and religious‐use spectrum. Bioclimatic factors, especially the minimum temperature of the coldest month, were the dominant drivers. During the trans‐climatic‐zone dissemination of Buddhism in China, the growth of original BTS (OBTS) from the India source area was stifled outside tropical and subtropical zones. The climatic constraints demanded the recruitment of substitute BTS (SBTS) from the indigenous flora. The same suite of religious uses was assigned to different BTS through the substitution process. With a weak environmental filter, indigenous species with close phylogenetic relationships and morphological similarity to OBTS were preferentially selected as substitutes. However, under a strong environmental filter, the selection was compelled to favour indigenous species with a distant phylogenetic relationship but similar part‐specific organ morphology (leaf or fruit) to OBTS. Ultimately, Buddhism, as an alien religion, influenced indigenous biodiversity mainly by localizing BTS and facilitating their spread and preservation. Read the free Plain Language Summary for this article on the Journal blog.

Premise: Parenchyma is an important cell type in the secondary xylem of angiosperm trees, with considerable variability in its abundance. However, the functional significance of these variations and their roles in plant ecological strategies is poorly understood at the inter‐ and intraspecific levels.Methods: For this study, fractions of axial parenchyma cells (AP) and ray parenchyma cells (RP) in xylem tissue were quantified for 156 individuals of 45 tree species along an elevational gradient from 600 to 1600 m a.s.l. in eastern China. Environmental factors and height of sampled trees at each sampling site were also measured. Linear mixed models were employed to assess the relative extent of both intraspecific and interspecific variations in parenchyma cells in xylem tissue fractions and to identify intraspecific variations along environmental gradients (e.g., temperature and humidity) and tree heights.Results: Interspecific variations explained the large diversity in AP fractions. Conversely, intraspecific variations accounted for ~50% of the overall variations in RP fractions. Further, intraspecific variations in the RP and the total AP and RP fractions exhibited negative correlations with tree heights but showed no significant relationship with climate.Conclusions: Intraspecific variations in parenchyma cells in xylem tissue fractions are not necessarily an adaptation or acclimation to changes in the environment but are coordinated with tree heights.

Urbanization greatly impacts both the diversity of soil seed banks and the spatial dynamics of species. These seed banks serve as a window into the ecological history and potential for recovery in urban wastelands, which are continually evolving due to urbanization. In this study, we selected 24 plots along urban-rural gradients in Shanghai, China. Soil samples were collected from each plot for seed bank germination experiment in both spring and autumn. We tested whether the seed density, species diversity, and composition of soil seed banks in wasteland varied along an urban-rural gradient. The results showed that seed density was higher in autumn than in spring and no significant difference was found along urban-rural gradients. A total of 74 species, belonging to 26 families and 69 genera, was recorded in soil seed banks, in which annuals were the dominant life form and autochory was the dominant dispersal model. The proportion of exotic species was nearly 40%. There is no significant difference along urban-rural gradients for functional composition, species diversity, and species composition, excepting that marginal significant for autumn Shannon-Wiener index and species composition among urban-rural gradients. The relative homogeneity in the seed bank across urban-rural gradients may primarily be due to the young age of the wastelands.

Resilience to drought represents an important focus for trees during climate change, with the aim of predicting the resistance and recovery of species worldwide. Previous studies mainly linked tree growth resilience to plant functional traits that are related to resource acquisition and investment. Here, we investigate a potential link between resilience and the amount of parenchyma tissue in wood, a multifunctional tissue that may provide various physiological benefits to drought‐related mechanisms. We compiled a global tree‐ring data set to evaluate the relationship between growth resistance, resilience or recovery from drought and xylem parenchyma tissue fractions of 50 angiosperms, which was complemented with a local study of nine species from Mt. Tiantong in China. We also assessed the influence of climate and phylogeny on these relationships. We found that growth recovery after drought was positively related to the fractions of total parenchyma locally and globally. This association remained statistically significant when accounting for the effects of climate and phylogeny. No other associations between parenchyma fractions and growth resilience metrics were statistically significant. Our results suggest that drought recovery of angiosperm trees is affected by the amount of parenchyma. Incorporating xylem parenchyma fraction with other traits, such as hydraulic traits, could therefore enhance our comprehension of how various angiosperm tree species will respond to future droughts. Further studies should focus on unravelling the physiological roles of xylem parenchyma fraction. Read the free Plain Language Summary for this article on the Journal blog.

Background: Vegetation science research has been conducted for approximately 200 years; however, until now there has not been a unified classification principle or system that was acceptable to vegetation scientists. To facilitate the development of vegetation science and its applications in natural conservation, a unified vegetation classification system is urgently required. Here we propose a unified eco‐physiognomic‐floristic vegetation classification system (EcoFloVCS) that combines eco‐physiognomic and floristic characteristic classification systems.Methods: Under the EcoFloVCS, plant communities are considered to have six key components (species composition, structure, habitat, development, locality, and function). Six associated characteristics are derived from these six components (dominant species, diagnostic species, physiognomy, distribution patterns, dynamics, and disturbance processes). These characteristics are used as the basis for community classification.Results and Conclusions: The high‐level units of this system agree with the UNESCO system, whereas the middle‐ and low‐level units correspond to the Braun‐Blanquet classification system. Both are connected by a Division (Subformation) unit. Based on the EcoFloVCS, a vegetation system was constructed for the four highest units worldwide that included seven Formation Classes, 22 Formation Subclasses, 39 Formation Groups, and 119 Formations. We assume that vegetation science will benefit from our unified EcoFloVCS through comparing and understanding community structures and functions on a global scale.

Beta diversity patterns along environmental gradients and underlying mechanisms constitute key research inquiries in biogeography. However, ecological processes often also influence the functional traits of biological communities, making the assessment of functional β‐diversity crucial. Ground beetles (Coleoptera: Carabidae) are one of the most species‐rich groups in the insect community, displaying strong habitat specificity and morphological differences. In this study, we explored the patterns of taxonomic and functional beta diversity in ground beetle communities along the altitudinal gradient of warm‐temperature forests. By partitioning beta diversity into turnover and nestedness components, we evaluated their relationship with spatial distance. Our findings indicate a decline in species and functional trait similarity with increasing elevation and geographic distance. Further analysis attributed both types of beta diversity in carabids to a combination of dispersal limitation and environmental filtering, with elevation and geographic distance emerging as significant factors. Interestingly, forest‐type variations were found to have no impact on the beta diversity of these communities. Our study reveals the impact of environmental filtering and dispersal limitation on both taxonomic and functional beta‐diversity, shedding light on carabid community assembly in localized warm‐temperature forest areas in eastern China.