Rocky desertification (RD), a natural and human-induced process of land degradation in karst areas, has become the primary ecological disaster and one of the obstacles to sustainable ecological development in southwest China. Nevertheless, the variation of soil physical and chemical properties, bacterial and fungal communities, and their relationships in RD forests remains limited. Therefore, soil samples were collected from forests under four degrees of RD (NRD, non-RD; LRD, light RD; MRD, moderate RD; and SRD, severe RD) and subjected to high-throughput sequencing of 16S rRNA and ITS1 genes. The results showed a significant reduction in bacterial richness and diversity, while fungal richness and diversity decreased markedly and then showed a balanced trend with the increase in RD degree, indicating that bacteria and fungi did not present the same dynamics in response to the process of RD. The bacterial communities were dominated by Proteobacteria, Actinobacteria, Acidobacteria, and Chloroflexi, while the fungal communities were dominated by Basidiomycota, Ascomycota, and Mortierellomycota. The PCoA and NMDS demonstrated significant differences in microbial communities in study sites, among which the fungal communities in non-RD forest and LRD forest clustered together, suggesting that fungal communities were more stable than bacteria in RD forest. The db-RDA, Mantel test, and random forest model confirmed the important role of soil BD, pH, SOC, AN, and AP in driving microbial diversity and communities. The IndVal analysis suggested that Chloroflexi, Patescibacteria, Atheliales, and Cantharellales with high indicator values were identified as potential bio-indicators for RD forests. This study could not only improve our understanding of bacterial and fungal community dynamics across RD gradients, but also could provide useful information for the further use of microorganisms as indicators to reflect the environmental changes and ecosystem status during forest RD.

Quercus rehderiana Hand.-Mazz. belongs to Quercus sect. Heteroallenes’ of the Fagaceae family. It is widely distributed in forests with rocky and non-rocky desertification in Guizhou Province of Southwest China. However, our knowledge of the adaptation strategies of Quercus in forests with rocky desertification is surprisingly lacking. In this study, 16 leaf traits (morphological, anatomical, and chemical) of Quercus rehderiana were investigated in 15 individuals in five 20 × 20 m quadrants of forests with rocky and non-rocky desertification. The aim was to analyze their strategies of adaptation to arid and poor-soil environments in forests with rocky desertification. The results showed that Quercus rehderiana leaves in forests with rocky desertification had a greater leaf thickness, specific leaf area, abaxial epidermis thickness, and sponge mesophyll thickness but a lower leaf area than in forests with non-rocky desertification. Quercus rehderiana leaves in forests with rocky desertification had higher calcium and magnesium concentrations and a higher N:P ratio but lower potassium and phosphorus concentrations than in forests with non-rocky desertification. The results of principal component analysis showed that forests with rocky desertification tended to show resource-conserving strategies with thicker leaf tissue and a lower nutrient concentration, while forests with non-rocky desertification tended to show resource acquisition strategies with a greater leaf area and potassium concentration. In resource-poor environments, species that adopt conservative resource strategies are more likely to survive; therefore, we forecasted that more conservative, slow-growing Quercus rehderiana will be more stable over time.

Isoetes yunguiensis is a rare and endangered fern endemic to Yunnan–Guizhou Plateau, China. The complete chloroplast genome sequence of I. yunguiensis was generated by de novo assembly using whole genome next-generation sequencing. The cp genome of I. yunguiensis was a circular structure and 145,355 bp in length, comprising a pair of inverted repeat (IR) regions of 26,130 bp, a large single copy (LSC) of 91,923 bp, and a small single copy (SSC) of 27,302 bp. The genome encoded 124 unique genes consisting of 82 protein-coding genes, 32 transfer RNA, four ribosomal RNA genes, and six pseudogenes. A maximum-likelihood phylogenetic analysis revealed that I. yunguiensis was closely related to I. butleri, I. engelmannii, I. flaccida, I. melanospora, and I. valida, with strong support values.

Ecological restoration has increasingly been employed to reverse land degradation and increase carbon (C) sink, especially in ecologically fragile karst areas. Microbial necromass carbon (MNC) constitutes a critical pool within soil organic carbon (SOC), contributing substantially to long-term C sequestration through mineral stabilization. However, its distribution patterns across soil profiles and grassland restoration stages in karst areas remain unclear. To address this knowledge gap, the contents of bacterial necromass C (BNC), fungal necromass C (FNC), and their contributions to SOC were estimated based on glucosamine and muramic acid contents across the soil profile (0–20 cm, 20–40 cm, 40–60 cm, 60–80 cm, and 80–100 cm) for four subalpine restoration stages (grazing enclosure for 5, 11, 17, and 25 years) in the karst region. Our findings demonstrated that both soil depth and grassland restoration stages effectively influenced the BNC and FNC contents. On average, the soil BNC, FNC, and total MNC at the depth of 80–100 cm reduced by 70.50%, 59.70%, and 62.18% compared with in topsoil (0–20 cm), respectively. However, the FNC/BNC ratio gradually increased with the increase in soil depth, which was 43.15% higher at 80–100 cm soil depth than in topsoil, suggesting that the accumulation efficiency of FNC was higher compared to BNC in the deep soil. The BNC, FNC, and MNC were positively correlated with the grassland restoration stage, while FNC/BNC ratio had a negative relationship with the restoration stage (R² = 0.45, p < 0.001). FNC contributed significantly more to SOC (28.6–36.4%) compared to BNC (7.7–9.9%) at all soil depths, indicating that soil fungal necromass has an essential effect on SOC sequestration. The results of the random forest model and distance-based redundancy analysis identified that pH, soil water content, and dissolved organic carbon were the three most essential predictors for the contribution of MNC to SOC. Our study highlights the importance of microbial necromass to SOC accumulation, providing significant scientific implications for the C pool management during the restoration of degraded grasslands in karst regions.

Phragmites australis is a well‐known invasive grass in North America, but its rapid expansion into new habitats within its native range is less documented. Here, we report a rapid expansion event of P. australis over the past decade in Caohai Lake, a plateau lake in China. Remote sensing and field surveys revealed that the reed population now covers 454.09 ha, constituting 3.8% of the protected area (approximately half of the total lake shoreline), with the most significant expansion occurring between 2018 and 2020. Ecological niche modeling with the previous records in China indicated a low habitat suitability (index = 0.354) for P. australis in this region. Despite this, our genetic analysis identified that all sampled individuals belong to haplotype P, an introduced octoploid lineage from eastern China. This finding excludes a natural range expansion from native populations in northern or southwestern China. The expansion is likely driven by anthropogenic habitat modification (e.g., “returning farmland to wetland”) and the introduction of this competitive genotype via constructed wetlands. Our study underscores the risk of “cryptic invasions” by introduced lineages within a species' native range and highlights the need for monitoring intraregional genotype translocations.

Pseudotsuga sinensis is a distinctive plant species endemic to China, predominantly found in areas affected by varying degrees of rocky desertification. Despite its wide distribution, the physiological mechanisms underlying its adaptation to harsh environments remain unclear. In this study, we investigated 16 leaf traits, including the morphological, anatomical, and chemical characteristics of the leaves of P. sinensis across forests with mild, moderate, severe, and extremely severe rocky desertification to elucidate the adaptive strategies of P. sinensis in response to arid conditions and nutrient‐poor soils. Our findings revealed that P. sinensis leaves from forests with mild and moderate rocky desertification exhibited higher specific leaf area (SLA) and magnesium concentrations but lower leaf dry matter content (LDMC), abaxial epidermis thickness, and adaxial epidermis thickness than in those from forests with severe and extremely severe desertification. Principal component analysis indicated that forests with mild to moderate desertification employ resource acquisition strategies characterized by greater SLA and magnesium concentrations than those in forests with severe and extremely severe desertification. In contrast, forests with severe to extremely severe desertification adopted resource‐conserving strategies, as evidenced by higher LDMC, epidermal thickness, and calcium concentrations than those in forests with mild to moderate desertification. The N:P ratio of P. sinensis across all desertification levels was consistently below 14, suggesting nitrogen limitation in P. sinensis in regions with rocky desertification. Thus, these results provide valuable reference for guiding vegetation restoration under degraded habitats.