Global Change Biology最新文献

Freshwaters face increasing pressures from chemical, hydrological and climatic changes, yet tools for assessing their condition remain limited. River biofilms, composed of diverse microbial communities, integrate environmental signals over space and time, making them sensitive indicators of river health. Using 16S rRNA gene sequencing of more than 1600 biofilms collected across a national river network, we quantified bacterial diversity and community composition and applied network analysis to identify ecologically cohesive sub-communities with keystone taxa underpinning community stability. Alkalinity, dissolved oxygen, nitrate-nitrogen and temperature were among the principal gradients shaping community composition. Threshold indicator analyses identified taxa with breakpoints along these gradients, revealing interpretable ecological thresholds. Our results demonstrate the potential for microbiome-based monitoring frameworks that could complement existing biotic indices, enabling early detection of ecological changes and supporting the integration of genomic indicators into routine ecosystem assessment. This scalable approach offers a powerful strategy for managing freshwaters under accelerating anthropogenic pressures.

Permafrost forests harbor vast, climate-sensitive carbon (C) reservoirs whose vulnerability largely depends on temperature sensitivity of microbial respiration (Q₁₀). However, substantial uncertainties persist in predicting Q₁₀ patterns due to complex interactions among multiple ecological factors. Here, we conducted a standardized field survey with controlled incubations across a regional gradient from continuous permafrost (CP) and discontinuous permafrost (Dis-CP, including sporadic and isolated ones) in the Greater Khingan Mountains to quantify Q₁₀ values and identify their main ecological controls. We found that the Q₁₀ values were significantly higher in CP than Dis-CP forests, indicating a stronger microbial respiratory response to warming in the coldest permafrost regions. Statistical analysis revealed that the soil microbiome was the most important factor explaining Q₁₀ values in CP forest (47.8%), whereas a distinct set of factors (plant production, fine texture, substrate quality, and mean annual ground temperature) explained the largest proportion (63.2%) of Q₁₀ variation in Dis-CP forests. Our findings suggest that warming-induced permafrost degradation is likely to shift the dominant controls for Q₁₀ from microbial community to abiotic and plant-related factors, while enhancing greenhouse gas emissions from permafrost soils.

Biological invasions are a major driver of global change, and prevention is the most effective mitigation strategy. Bioclimatic species distribution models (SDMs) are widely used to estimate invasion risk, assuming that species retain their realized native climatic niches after introduction. We tested this assumption for 194 alien mammal species established across 11 zoogeographic realms, examining realized niche changes, their drivers, and significance for invasion projections. We used a robust ordination framework to compare native and alien niches in 337 species-by-realm niche comparisons and quantify niche expansion, the proportion of the alien niche not overlapping with the native niche, and niche unfilling, the proportion of the native niche not overlapping with the alien niche. We then applied Generalized Linear Mixed Models (GLMMs) with multi-model inference to test how species attributes, invasion history, and environmental context are associated with expansion and unfilling. Additionally, we evaluated the transferability of SDMs built on native presences to receiving regions using multiple metrics and used GLMMs to assess how niche changes may affect it. Niche expansion was rare and modest, whereas niche unfilling was common and pronounced. Niche expansion declined with increasing human disturbance, larger native range size, and introductions within similar communities, but increased with higher introduction effort. Niche unfilling decreased with greater introduction effort and longer residence time, but increased with alien insularity, human disturbance, and native range loss. SDM transferability was generally good, but it declined with niche expansion, as alien presences fell outside native-like suitable areas, and with unfilling, because suitable areas remained unoccupied under colonization lags. Proactive management can rely on SDMs to anticipate future spread and should prioritize species showing high niche unfilling, indicating substantial spread potential, and any evidence of niche expansion, which makes spread harder to anticipate.

Forestation is a pivotal nature-based strategy for enhancing soil organic carbon (SOC) sequestration, yet the differential impacts of pure versus mixed-species plantations on SOC fractions and stability remain poorly quantified at a global scale. To address this knowledge gap, we performed a meta-analysis of 4052 observations from 102 sites and showed that mixed forestation significantly increases SOC, particulate organic carbon (POC), and mineral-associated organic carbon (MAOC) by 64.3%, 86.9%, and 65.3%, respectively, whereas pure forestation enhances SOC and POC but has no significant impact on MAOC. Critically, pure forestation reduced the MAOC:POC ratio-a key indicator of SOC stability-by 24.9%, while mixed forestation maintained or enhanced it. Prior land use type was the dominant regulator of SOC fraction responses, with plantation age further moderating SOC accrual and stability. Mixed forestation also promoted greater soil nitrogen, microbial biomass, and dissolved organic carbon, supporting MAOC formation and SOC stability. Our results demonstrate that mixed forestation simultaneously enhances SOC storage and stability, offering a more resilient pathway for terrestrial carbon sequestration under global change. These findings underscore the need to prioritize mixed-species plantations in reforestation policies to achieve climate mitigation and ecosystem restoration goals.