Si‐Chong Chen

Aim: Anthropogenic pollution is a pervasive driver of global change, yet its ecological impacts on wild plants remain relatively less synthesised, particularly for their regeneration. Quantifying how pollution, such as heavy metals, threatens seed‐to‐seedling transitions in wild plants is essential for understanding species persistence, community resilience, and vegetation dynamics under accelerating environmental pressures. However, the quantitative impacts of pollution on wild plant regeneration remain poorly understood at a broad scale. Location: Global. Time Period: 1990 to 2024. Major Taxa Studied: Wild plants. Methods: We conduct a global meta‐analysis of 4476 experiments from 107 publications to quantify the effects of pollution on the earliest life stages of 162 wild plant species. Results: Pollution significantly inhibits wild plant seed‐based regeneration by an average of one‐third. Specifically, pollution reduces seed germination by 33%, prolongs germination speed by 29%, and suppresses seedling growth by 42%. Pollution also disproportionately suppresses below‐ground growth of seedlings, altering root‐to‐shoot biomass allocation by 27%. While these inhibitory impacts are qualitatively consistent across species and pollutant types, pollutant type and concentration are more important quantitative predictors of these impacts than plant characteristics such as growth form and seed mass. Heavy metals exhibit a dual, concentration‐dependent effect, with low concentrations (< 0.05 mg/L on average) facilitating regeneration and high concentrations severely impairing it. Main Conclusions: These findings suggest pollution acts as a powerful “regeneration filter”, favouring pollution‐tolerant, often invasive, “winner” species over sensitive native “losers”, thereby reshaping community assembly and exacerbating biotic homogenisation. By quantifying this severe ecological bottleneck, our study provides quantitative evidence that pollution poses a pervasive threat to biodiversity, with impacts on a critical life stage rivalling other major drivers of global change. These findings underscore the urgent need to integrate pollution mitigation into conservation frameworks like the Kunming‐Montreal Global Biodiversity Framework to safeguard ecosystem function and resilience.

Summary: Plant functional traits connect biodiversity to ecosystem processes, serving as key metrics for assessing how biota responds to environmental conditions. Functional seed traits are critical because they underpin recruitment and colonization, shaping biodiversity patterns and influencing ecosystem resilience. Yet, seed traits remain underrepresented in major data repositories, with severe gaps in the tropics. Climatic, geological, and historical differences between tropical and temperate regions drive distinct regeneration dynamics, suggesting that the paucity of tropical seed trait data limits our ability to predict regeneration niches and weakens global models largely based on temperate ecosystems. To address this gap, we introduce the Tropical Seed Trait Database (TSTD), an open‐access repository spanning the full ecological spectrum of tropical seeds. The TSTD is conceived as a community‐driven repository of primary data contributed directly by data owners, rather than as a secondary aggregation of global databases. It was built through contributions from ecologists working across all tropical regions, reached through direct contact, and its first version compiles 78 datasets, totaling 137 583 records across 44 functional traits. Covering 5115 species in 33 countries, with the Neotropics overrepresented, the TSTD marks a crucial step toward more inclusive, globally representative trait databases that can open multiple research avenues.

A lack of standardised sampling protocols prevents functional traits from expressing their full potential to advance plant ecology, biogeography, and evolutionary biology. Handbooks providing protocols for standardised measurements of plant functional traits allow researchers to tackle large-scale ecological questions but have traditionally focused on vegetative traits such as leaves, stems and roots. This handbook provides standardised protocols for 58 reproductive traits of flowers (10 traits), fruits (6 traits), seeds (36 traits) and seedlings (6 traits). It is the first effort to standardise sampling for relevant reproductive traits to better understand processes, such as pollination, frugivory, seed dispersal, seed longevity, germination, and seedling establishment. The protocols were designed to embrace the global diversity of ecological contexts experienced by flowers, fruits, seeds, and seedlings and incorporate methods for temperate to tropical, dry to moist and fire-prone to fire-sensitive ecosystems. We offer general guidelines for sampling, storing, and processing reproductive traits. Before laying out the protocol, we briefly describe each trait functionality, trade-offs, and sources of variability to give a broad context. Standardised protocols to estimate reproductive plant traits will unlock the full potential of plants to mitigate land-use and climate-change impacts, and support restoration of degraded ecosystems.

Masquerade is a sophisticated form of camouflage in which organisms have evolved morphological traits that closely resemble inanimate objects within their environment, thereby reducing detection by potential predators [1,2]. Classic examples include stick insects (Phryganistria spp.) mimicking twigs, caterpillars of swallowtail butterflies (Papilio spp.) and the spider Ornithoscatoides decipiens, both resembling bird droppings [1]. In contrast, cases of masquerade in plants are exceedingly rare, with the living stones (Lithops spp.) of South Africa being a well-known example [3]. Here, we report evidence of an unusual plant organ masquerade case in Phyllolobium heydei, whose fruits have evolved to a striking resemblance to surrounding stones in alpine scree habitats. This phenotypic adaptation likely enhances reproductive success by reducing herbivore damage in harsh alpine environments.

Observation methods are crucial for understanding ecological processes. One widely used method is the application of plasticine models that visually mimic prey organisms in assessing biotic interactions. However, questions remain about whether this approach may accurately capture specific interaction intensity and types. Here, we initially synthesized previous studies applying plasticine models to quantify different types of biotic interaction. Following the experimental designs in these studies, we deployed 2430 plasticine models with different sizes, shapes and colours, mimicking various prey types, in natural habitats located in two different biomes across multiple seasons. Our results revealed that attack rates were not significantly different among plasticine models with varying characteristics, whether attack marks were pooled or separated by different animal guilds. This suggests that animals may not consistently distinguish visually different plasticine models as distinct prey types, and attack rates on plasticine models may be influenced by overall animal richness and activity levels rather than exclusively reflecting specific biotic interactions. Our study indicates the existence of anthropocentric biases in the application of plasticine models to assess biotic interactions. We highlight the importance of incorporating the habits and behaviours of studied animal taxa in ecological experimental designs to minimize anthropocentric biases and ensure an accurate assessment of ecological processes.

Biotic interactions play an important role in species diversification and maintenance and, thus, are regarded as the architecture of biodiversity. Since Darwin and Wallace, biologists have debated whether biotic interactions are stronger towards the tropics and on continents, when compared to temperate regions and islands. Here, based on 354 avian frugivory networks accounting for 22,199 interactions between 1247 bird species and 2126 plant species, we quantified trait matching strength, which reflects interaction strength and specificity, across gradients of latitude and insularity globally. We found that matching between beak size and fruit size was significantly stronger towards the poles and on continents, when compared with the tropics and on islands. As underlining ecological factors, trait matching was stronger with a larger proportion of frugivory (measured as the mean proportion of fruits in bird diets) and network‐level mean beak size, and with a smaller proportion of fleshy‐fruited species (measured as the proportion of fleshy‐fruited plant species in the botanical country where the network was located). These findings suggest that the latitudinal and insular patterns in trait matching are driven by biotic factors that may relate to trait co‐evolution between interacting species and optimal foraging for bird species.

Large seeds interact with a wide range of animals (e.g. predators) and are dispersed via certain small animals' foraging behaviours, such as caching. Some of the most iconic species of large‐seeded plants have long fascinated ecologists studying biotic interactions, such as oaks and their relatives in the Fagaceae family. The Fagaceae acorns are dispersed through synzoochory, a specific dispersal mode in which animal partners act as both seed dispersers and granivores. Although granivory (i.e. seed herbivory) can profoundly impact the survival of plant offspring, partial damage on seed reserves is a prevalent phenomenon that does not always result in seed mortality. However, previous single‐species studies have resulted in mixed evidence across treatments and traits, leaving the impact of partial granivory on plant regeneration unclear. Using artificial granivory experiments on 1185 seeds of 20 Fagaceae species, here we quantify how partial loss of seed reserve affects seed germination, seedling growth and biomass allocation across a damage gradient from 0% to 96% biomass loss. We show that, although partial granivory reduces seedling growth (e.g. total biomass and number of leaves), it does not significantly affect seed germination or the overall biomass allocation of seedlings (e.g. leaf mass fraction and root:shoot biomass ratio). Seedlings from seeds more preyed upon have higher specific leaf area, indicating that they tend to grow larger but less protected leaves against herbivores, perhaps to compete for light. Synthesis. As seeds dispersed through scatter‐hoarding granivores have evolved relatively large sizes, like Fagaceae acorns, our findings demonstrate that this type of seeds may tolerate partial granivory in exchange for high dispersal efficiency. This study opens new perspectives to our understanding of seed size diversity and evolution. We conclude that seed size per se is a defensive trait, that large seeds counteract potential losses of seed reserve to escape full predation and allow germination.