Understanding how non-trophic social systems respond to environmental gradients is still a challenge in animal ecology, particularly in comparing changes in species composition to changes in interspecific interactions. Here, we combined long-term monitoring of mixed-species bird flocks, data on participating species' evolutionary history and traits, to test how elevation affected community assemblages and interspecific interactions in flock social networks. Elevation primarily affected flocks through reassembling interspecific associations rather than modifying community assemblages. Specifically, flock networks at higher elevations (compared to low elevations) had stronger interspecific associations (larger average weighted degree), network connectivity (enhanced network density) and fewer subnetworks. A phylogenetic and functional perspective revealed that associations between similar species weakened, whereas connections between dissimilar and/or random species were unchanged or strengthened with elevation. Likewise, network assortativity for the traits of vertical stratum and breeding period declined with elevation. The overall pattern is a change from modular networks in the lowlands, where species join flocks with other species that have matching traits, to a more open, random system at high elevations. Collectively, this rewiring of interspecific networks across elevational gradients imparts network stability and resiliency and makes mixed-species flocks less sensitive to local extinctions caused by harsh environments.

Mountains in China are crucial for biodiversity conservation due to unique topography and climate, providing essential habitats and refugia for many plant species. Standardized open datasets along elevational gradients across multiple mountains remain limited. Here we used standardized field protocols to collect plant diversity data of 370 permanent sampling plots along elevations in 17 mountains. Species identity and abundance of all woody plants with ≥ 1 cm diameter at breast height were recorded. We calculated species-level basal area, abundance, and relative importance value for all plants, and separately for two vegetation layers. The dataset spans 46° longitude, 24° latitude, ranges from 166 to 3,835 m a.s.l., and includes 1,493 species from 121 families and 450 genera. It covers nearly all major ecosystems from tropical rainforests to tundra, providing baseline data for studying plant diversity changes along elevations and latitudes. This dataset enables direct comparisons across mountains, helping evaluate impacts of climate and land-use changes on species range shifts and ecosystem transitions, and inform conservation strategies for mountain ecosystems.

Rapid urbanization and associated transportation play a crucial role in the distribution of heavy metals in road dust, leading to serious environmental and health concerns. This study explored the concentration and spatial variability of metals, including cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn), in road dust across six urban zones in Guangdong Province (parks, educational, residential, commercial, traffic, and industrial areas). The study also evaluated the bioavailability of these metals to determine their carcinogenic and non-carcinogenic health impacts. The findings revealed significant variations in metal levels, with commercial zones having the highest concentrations of Zn 1316.1 ± 381.6 mg/kg), Cu (426.1 ± 136.7 mg/kg), and Cd (1.29 ± 0.08 mg/kg) due to the deposition of traffic emissions. The bioaccessibility of Pb, Zn, and Cd was found to be higher in the gastric phase, suggesting increased absorption potential when ingested. Children were at a significantly higher non-carcinogenic risk compared to adults, facing more than double the exposure. While the carcinogenic risk from Pb was low but notable, Cd presented minimal risk. These results highlight the need for targeted interventions, including stricter emission regulations and public health strategies, to mitigate the risks of heavy metal exposure in urban areas.

Seasonal variation can strongly influence species interactions, yet its effects on interaction networks remain poorly understood in tropical and subtropical systems. We surveyed mixed-species bird flocks (MSFs) across 20 2 × 2 km grid cells in a subtropical forest in southern China during breeding and non-breeding seasons, quantified seasonal changes in flock composition and network structure, and examined how species traits and environmental factors drive these changes. More species and individuals joined mixed-species bird flocks in the non-breeding season, producing more connected and cohesive networks. During the breeding season, network structure was associated with breeding traits: species with larger clutch sizes showed higher association strength, but overall network connectivity and cohesion declined, suggesting trade-offs imposed by parental care. Network structure in the non-breeding season was related to morphological traits, with smaller species forming more cohesive networks. Environmental effects were also season dependent. Connectivity increased with elevation, forest cover and canopy cover in the breeding season, whereas in the non-breeding season networks were most connected and cohesive at low elevations with high tree species richness and vegetation productivity. Our results demonstrate the importance of seasonal effects on mixed-species bird flocks and highlight the need to maintain mountain connectivity, as communities may rely on different parts of mountains across seasons.

“Community informant” species serve as critical sources of information. However, interactions between multiple informant species in complex systems remain unclear, including whether they jointly contribute vocalizations and thus public information, eavesdrop on each other, or do not interact, and whether joint contributions provide benefits through complementary or supplementary mechanisms. We elicited mobbing calls using an owl model and alarm calls using a raptor model inside mixed‐species flocks (MSFs) in a two‐year survey on a 1650 km latitudinal gradient (18.7°N–33.7°N) in China, across which bird communities transition from babbler dominance in the south to tits in the north. We also constructed social networks to examine structural patterns along the gradient and assessed the influence of latitude on network metrics and the effect of group composition (Babbler‐Tit, Babbler, Tit, None) on vocal responses. Social network metrics peaked in interaction strength (for mobs) and cohesion (for MSFs) at mid‐latitudes. Alarm calls were brief and dominated by one babbler and two tit species, whereas mobbing calls were long‐lasting and contributed by many species (averaging 4.2 per trial). In small mobbing assemblages (1–5 species), Babbler‐Tit groups recruited up to 2.4 times more individuals and elicited 2.1 times more calls. Babbler‐Tit MSFs also involved up to 1.6 times more vocal species and generated vocalizations with up to 12.2 times broader frequency ranges, which potentially could be detected by more species. Therefore, protecting community informants and complex systems is essential to maintain information networks that underpin ecosystem resilience.