Many grasslands around the world are affected by shrub encroachment. The essence of shrub encroachment into a grassland habitat is a change in the direction and intensity of shrub–grass interactions, which leads to an alteration in the grassland community structure. Recent research progress can be summarized as encompassing the primary factors influencing shrub encroachment and the physical, biological, and chemical ways through which they affect grassland community succession and shrub–grass interactions. The purpose of this study was to explore how shrub–grass interactions and relationships change under the influence of various environmental factors and their impact on grassland communities to provide a theoretical basis for grassland restoration and the management of shrubs within grassland from the perspective of shrub–grass interaction.

Environmental conditions can control the structure and composition of plant communities by changing the direction and intensity of plant–plant interactions. In extreme arid regions, accompanied by water and soil nutrient limitation, positive shrub–herb interactions may vary along an aridity gradient, leading to changes in the ecological consequences of shrub encroachment. We investigated the vegetation and soil within 60 shrub patches and their paired interspaces at 20 sites from the northeast to southwest desert steppe of Inner Mongolia, China, encroached by the Caragana microphylla shrub. The results show that aridity, soil organic matter (SOM), and soil total phosphorus (TP) were the main factors driving shrub–herb interactions. The positive shrub–herb interaction first increased and then decreased with increasing aridity (in the range of De Martonne Index (DMI) 0.54 to 1.85). The DMI indirectly affected shrub–herb interaction through TP, and the facilitation of shrubs on herbs coverage and biomass increased with the increase in TP. The SOM can directly affect the shrub–herbs interaction, and the facilitation of shrubs on herb diversity decreases with the increase in SOM. Our results indicate that the shrub–herb interaction changes along the environmental stress gradient; in general, shrubs have a positive effect on herbaceous communities along the aridity gradient. This study underscores the positive effects of shrubs on vegetation restoration in desert steppes, and changing environmental conditions by increasing precipitation, increasing TP content, and reducing SOM content can enhance the facilitation of shrub on herbs to accelerate the ecological restoration of degraded desert steppe.

Background: Chironomidae occupy a pivotal position within global aquatic ecosystems. The unique structural attributes of the mitochondrial genome provide profound insights and compelling evidence, underpinning the morphological classification of organisms and substantially advancing our understanding of the phylogenetic relationships within Chironomidae. Results: We have meticulously sequenced, assembled, and annotated the mitogenomes of Tanypus chinensis (Wang, 1994) and Tanypus kraatzi (Kieffer, 1912), incorporating an additional 25 previously published mitogenomes into our comprehensive analysis. This extensive dataset enables us to delve deeper into the intricate characteristics and nuances of these mitogenomes, facilitating a more nuanced understanding of their genetic makeup. Conclusions: The genomic nucleotide composition of T. kraatzi was 39.10% A, 36.51% T, 14.33% C, and 10.06% G, with a total length of 1508 bp. The genomic nucleotide composition of T. chinensis was 39.61% A, 36.27% T, 14.55% C, and 9.57% G, with a total length of 1503 bp. This significant enrichment of the chironomid mitogenome library establishes a novel foundation for further exploration in the realm of phylogenetics.

Cytochrome P450 monooxygenases (P450s) are one of the most widespread enzyme superfamilies in the biological world. In insects, P450 proteins play a crucial role in the synthesis of endogenous substances and the metabolism of xenobiotics. To date, extensive research has been conducted on P450 gene-mediated detoxification and metabolism across multiple insect species. While Chironomidae species—dominant benthic organisms inhabiting diverse ecological niches and playing critical ecological roles—remain largely uncharacterized in terms of P450 protein annotation, with the exception of a single study on Propsilocerus akamusi. In this study, we expanded the annotation scope by identifying the P450 protein genes in eight additional Chironomidae species. A total of 577 P450 protein genes were annotated across the eight species, which could be classified into the following four distinct clans: 50 belonging to the CYP2 clan, 258 to the CYP3 clan, 198 to the CYP4 clan, and 71 to the Mito clan. Phylogenetic analysis using Drosophila melanogaster as an outgroup revealed that the CYP2 clan and the Mito clan are highly conserved during evolution, while the CYP3 clan and the CYP4 clan have undergone significant expansion. Most P450 proteins in Chironomidae species exhibit clear orthologous relationships with their D. melanogaster counterparts. Our research contributes to a better understanding of the evolutionary processes and the physiological functions of P450 proteins in Chironomidae species and lays the foundation for elucidating the role of P450 in environmental adaptability among the Chironomidae species inhabiting diverse habitats.

The ABC (ATP-binding cassette) transporter family constitutes one of the most extensive transmembrane transporter gene families found across all realms of life. In insects, ABC transporters are crucial for processes such as nutrient metabolism, regulating metamorphosis, and detoxifying xenobiotics. Chironomidae, a diverse aquatic insect group of significant ecological importance that does not bite, has lacked comprehensive annotation of ABC transporters, with the exception of our recent work on Propsilocerus akamusi. In this study, we broaden the annotation by detecting ABC transporter genes across eight additional Chironomidae species, which include all accessible genomes. A total of 454 ABC transporter genes were annotated across the eight species, categorized into eight distinct subfamilies: 67 belonging to the ABCA subfamily, 45 to ABCB, 105 to ABCC, 13 to ABCD, eight to ABCE, 23 to ABCF, 114 to ABCG, and 78 to ABCH. Phylogenetic analysis using Drosophila melanogaster as an external reference revealed clear orthologous relationships for most Chironomidae ABC transporters, except for a notable expansion of the ABCH subfamily. This research offers crucial understanding of the evolutionary processes and physiological roles played by ABC transporters within the Chironomidae species, offering a foundation for understanding their role in the environmental adaptability of these species.