Forest fires are key ecological disturbances that influence vegetation dynamics and soil microbial processes central to carbon and nutrient cycling. While fire frequency and severity are increasing globally, the microbial mechanisms underlying ecosystem recovery remain inadequately understood. We used high-throughput amplicon sequencing to evaluate short-term effects of low- and high-severity fires on soil microbial diversity and co-occurrence networks following fire disturbance in a temperate forest. Fire severity had no significant impact on microbial α-diversity, but significantly altered β-diversity. Mantel tests indicated that soil pH and belowground biomass were the primary environmental drivers of bacterial and fungal community turnover under different fire severities. Further, network analyses revealed distinct microbial responses to fire severity: low-severity fire primarily restructured bacterial associations, whereas high-severity fire disrupted both bacterial and fungal networks. These findings suggest that microbial community structure and interactions are differentially sensitive to fire severity, with implications for soil functional resilience and ecosystem restoration strategies in fire-affected forests.

Environmental changes, especially climate variability, can substantially influence phenological patterns of plants and their associated insect communities, potentially reshaping the spatial distribution of their interactions. Despite considerable attention on species range shifts under climate change, empirical studies explicitly addressing how these shifts affect spatial matching between plants and their associated insect communities remain scarce. Here, we investigated inter-annual changes in the spatial matching between the poisonous weed Stellera chamaejasme L. and its associated floral visitor community along an altitudinal gradient over two climatically distinct growing seasons in the Qilian Mountains, China. We monitored the flowering phenology of S. chamaejasme and the abundance of its major pollinators (Meloidae, Tachinidae, Scarabaeidae and Noctuidae) at different altitudes. Our findings show a pronounced altitudinal displacement between the peak abundance zones of S. chamaejasme and its major pollinators, indicating spatial mismatches in both years (2021 and 2022). However, the increased preseason thermal accumulation in 2022 improved spatial matching, as high-density overlap zones shifted to higher altitudes, where insect visitation rates also increased. Additionally, the elevated preseason heat significantly advanced flowering phenology at high altitudes, which may contribute positively to breaking the altitudinal distribution limits of S. chamaejasme, along with enhanced spatial matching with pollinators. This study highlights the significant impact of inter-annual climate variability on spatial matching between mountain plants and pollinators at various altitudes, which is crucial for improving population dynamics models and enhancing the accuracy of predictions.

Mixed cultivation of Larix gmelinii and Juglans mandshurica is a typical strategy for increasing stand productivity in Northeast China. However, the adaptive strategies of fine roots and root-associated fungi (RAF) after mixed cultivation remain unclear. Here, we examined the chemical, morphological and anatomical characteristics of fine roots, along with the composition, diversity and co-occurrence network structure of their RAF communities. Our results showed that mixed cultivation increased the root diameter and root tissue density of first-order to third-order fine roots for both L. gmelinii and J. mandshurica but decreased the specific root length. The root economic spectrum of the two species demonstrated a shift from a ‘do-it-yourself’ strategy to an ‘outsourcing’ strategy in their first- and second-order roots after mixed cultivation. Arbuscular mycorrhizal fungi and endophytic fungi were the main fungal functional groups within the RAF of J. mandshurica, while ectomycorrhizal fungi were dominant in those of L. gmelinii. Mixed cultivation increased the RAF alpha diversity of J. mandshurica but decreased the RAF alpha diversity of L. gmelinii. Negative correlations in the co-occurrence networks of the RAF communities accounted for >50% of the two species, indicating that competitive relationships dominated within the RAF community. Changes in the composition of RAF after mixed cultivation effectively supported shifts in the root economic spectrum of the two species. The coordinated changes in fine root systems and their associated mycorrhizal fungi enable the two species to maintain their competitive edge in nutrient absorption when they are planted together.

Leaf economic, hydraulic and anatomical traits play crucial roles in plant adaptation to diverse and variable environments. However, their relationships at the intraspecific level remain unclear. In this study, we investigated Quercus variabilis, a species spanning temperate to subtropical zones, to assess functional trait variation along a north-to-south environmental gradient in China (24°94′–40°26′ N). We analyzed 10 key functional traits, including leaf mass per area (LMA), leaf thickness (LT), leaf tissue density (LTD), leaf nitrogen concentration (LN), stomatal density (SD), vein density (VD), stomatal guard cell length (SL), palisade tissue thickness (PT), spongy tissue thickness (ST) and palisade-to-spongy tissue ratio (PT/ST) across 9 natural populations. The results showed that Q. variabilis exhibited significant plasticity in functional trait variation, primarily driven by environmental factors, with mean annual precipitation (MAP) and soil total nitrogen (STN) emerging as key ecological drivers promoting the coordinated variation in leaf functional traits. Coordinated relationships were observed between leaf economic traits (LMA, LT, LTD, LN) and hydraulic traits (SD, VD, SL), which varied in response to environmental conditions. Furthermore, leaf anatomical traits (PT, ST, PT/ST) were closely linked to both hydraulic and economic traits. These findings provide valuable insights into the adaptive strategies of Q. variabilis and enhance our understanding of plant responses to environmental change at the intraspecific level.