Niche partitioning is one of the key mechanisms allowing species co-existence and is especially relevant in species-rich communities. For pollinators, morphology is a major axis in which species differentiate their foraging niche, as it influences the match with flower morphology. Bumblebees (Bombus spp.) are important pollinators globally, showing their highest diversity of co-occurring species in the Hengduan Mountains region of southwestern China. This community context makes the region an ideal model system to test the importance of niche partitioning for plant-pollinator interactions. In high-elevation flower-rich meadows, over four years, we sampled pollinator-plant interaction networks containing 12 sympatric bumblebee species, varying more than fourfold in tongue length from 4.7 to 21.7 mm. We then assessed the degree of niche partitioning occurring between these bumblebees. We analysed bumblebees’ foraging niche widths and overlap and found that species with longer tongues foraged from a narrower range of flowers. Accordingly, bumblebee species having shorter tongues and visiting a higher diversity of flowering species also showed consistently higher floral overlap with other bumblebee species across years. In spite of this morphology-driven niche pattern for species, the interaction network was consistently characterized by high generalization across the years. Our results indicate that the co-occurrence of a large number of potentially competing pollinators with high generalization and niche overlap is possible in flower-rich habitats. We suggest that, in regions of extraordinarily high plant and pollinator diversity and abundance, diverse pollinator communities may also be maintained without strong foraging niche partitioning.

The strength of interspecific and intraspecific competition depends on resource availability, competitor abundance, and specialization. Most studies are conducted with single species pairs, constraining our understanding of what drives competition in multispecies communities. We investigated the effect of floral density, competitor abundance, flowering period, and trait specialization (proboscis length) on the potential for interspecific and intraspecific competition between seven common bumblebee species in the Hengduan Mountains of southwest China. We estimated the potential for interspecific and intraspecific competition using resource partitioning indices in plant-bumblebee networks (Müller’s index) over five consecutive years, quantifying changes in floral densities and bumblebee abundance throughout the season. The potential for interspecific competition increased with bumblebee abundance, particularly when floral density was low later in the season. On the other hand, the potential for intraspecific competition increased with abundance of focal bumblebee species and for specialized long-tongued bumblebees, especially when floral density was low. This suggests that resource scarcity regulates species coexistence by limiting abundant species dominance via interspecific competition and intraspecific competition. Our results indicate the importance of intraspecific competition and specialization in maintaining diversity in multispecies communities.

All Plant biomass and fungi asv are given in the data

Climate warming and anthropogenic activities have led to an increase in the prevalence of non-native plants in mountainous regions that previously exhibited limited occurrences. This phenomenon has resulted in detrimental effects on endemic plants and ecosystem functions. However, the variation in traits of non-native plants that successfully spread to high elevations, as well as the underlying drivers of these changes, remains poorly understood. In this study, we use Erigeron annuus, a cosmopolitan non-native plant that has invaded high elevations, as our model to explore its individual biomass pattern along a 1900 m elevation gradient. We also contrast this pattern with that of the native Artemisia lavandulifolia, which has the same distribution range as E. annuus. We found that the biomass of E. annuus displayed a hump-shape pattern along elevation, while the biomass of the native A. lavandulifolia gradually decreased with increasing elevation. By evaluating the effects of climate variables, soil properties, rhizosphere fungal communities, and their spatial mid-domain effect (i.e., geographic limitation) on plant biomass, we found that the biomass of E. annuus was primarily influenced by the spatial mid-domain effect, while the biomass of A. lavandulifolia resulted from a complex interplay of climatic variables and rhizosphere microbial communities. Our findings emphasize the importance of a spatial mid-domain effect on the growth of non-native E. annuus across elevation, indicating that the impact of E. annuus is probably greatest at mid-elevations and thus, where management priority should be set. Further investigations considering more non-native plant species and species’ traits will allow us to scrutinize this vision.

Scientific theory largely neglects linkage between organic phosphorus (Po) mineralization rate and dispersal potential of alkaline phosphatase-encoding bacteria (PEB) containing the phoD gene. Different densities of substrates (i.e., compacted soils, culture media, and soil aggregates) were prepared and molecular tools were used to unveil relationship between dispersal potential of PEB and Po mineralization rate. According to morphological observations and ecological studies, we found that the stronger dispersal potential of PEB ensured a higher Po mineralization rate. Higher Po mineralization rates were found in soil microaggregates than in macroaggregates and silt + clay, and soil Po mineralization rate was related closely to P fractions distributed heterogeneously in aggregates. The phoD gene abundance was notably correlated with Po mineralization rate, and rare PEB mediated Po mineralization. The Bradyrhizobium as identified genus dominated in dramatically heterogeneous PEB community, and stochasticity (70.5–89.5%) affected more on community assemblages of PEB. The PEB showed a stronger dispersal potential in microaggregates than the other aggregates, as indicated by weaker community stability, stronger species replacement, higher migration rate, lower environmental constraint, and broader niche breadth. Overall, our results emphasize that a stronger dispersal potential of PEB ensure a higher Po mineralization rate, and these findings broaden our understanding of how PEB maintain landscape and function in soils.

The present repository provides a FASTA resource with reference sequences of major repetitive DNA sequences from the genomes of Hydnora and Prosopanche species. This sequence list is complemented by a GFF file with detailed annotations for the included retrotransposons. The nuclear genomes of parasitic plants have undergone unique evolutionary trajectories to adapt to the heterotrophic lifestyle. These adaptations often involve large genomic alterations, potentially driven by repetitive elements. Despite the well-recognized role of repetitive DNAs as evolutionary forces in shaping plant genomes, their role in genome evolution of parasitic plants remains largely unexplored. To address this knowledge gap, we conducted the first analysis of repetitive DNAs in eleven genomes of Hydnoraceae, a family of mostly non-crop parasitizing holoparasites.The observed repeat abundance profiles and presence-absence patterns align with the phylogenetic relationships, geographical distribution, and host shifts, suggesting a key role of repetitive DNAs in shaping Hydnoraceae genomes. The repetitive fraction of the two Hydnoraceae genera, Hydnora and Prosopanche, are fundamentally different: Whereas the eight analyzed Hydnora genomes are largely populated by long terminal repeat retrotransposons, particularly of the Tekay and Ogre type, the three Prosopanche repeatomes differ vastly in individual abundances, including P. bonacinae with massive amplifications of a single DNA transposon and P. panguanensis with over 15% 5S rDNA (as opposed to some Hydnoraceae with <0.1% 5S rDNA). Both extremely low and very high abundance of 5S rDNA challenges our current understanding for chromosome stabilization and rRNA transcription.These genome dynamics suggest rapidly evolving repeat profiles, potentially being enhanced by the adaptation to the parasitic lifestyle. The heterogeneous abundance of rDNAs and DNA transposons in Hydnoraceae genomes needs further attention, with regard to repeat-driven evolution. This study lays the groundwork for future genomic explorations on Hydnoraceae, as well as heterotrophic plants and their nuclear genome composition in general.

The present repository provides a FASTA resource with reference sequences of major repetitive DNA sequences from the genomes of Hydnora and Prosopanche species. This sequence list is complemented by a GFF file with detailed annotations for the included retrotransposons. The nuclear genomes of parasitic plants have undergone unique evolutionary trajectories to adapt to the heterotrophic lifestyle. These adaptations often involve large genomic alterations, potentially driven by repetitive elements. Despite the well-recognized role of repetitive DNAs as evolutionary forces in shaping plant genomes, their role in genome evolution of parasitic plants remains largely unexplored. To address this knowledge gap, we conducted the first analysis of repetitive DNAs in eleven genomes of Hydnoraceae, a family of mostly non-crop parasitizing holoparasites.The observed repeat abundance profiles and presence-absence patterns align with the phylogenetic relationships, geographical distribution, and host shifts, suggesting a key role of repetitive DNAs in shaping Hydnoraceae genomes. The repetitive fraction of the two Hydnoraceae genera, Hydnora and Prosopanche, are fundamentally different: Whereas the eight analyzed Hydnora genomes are largely populated by long terminal repeat retrotransposons, particularly of the Tekay and Ogre type, the three Prosopanche repeatomes differ vastly in individual abundances, including P. bonacinae with massive amplifications of a single DNA transposon and P. panguanensis with over 15% 5S rDNA (as opposed to some Hydnoraceae with <0.1% 5S rDNA). Both extremely low and very high abundance of 5S rDNA challenges our current understanding for chromosome stabilization and rRNA transcription.These genome dynamics suggest rapidly evolving repeat profiles, potentially being enhanced by the adaptation to the parasitic lifestyle. The heterogeneous abundance of rDNAs and DNA transposons in Hydnoraceae genomes needs further attention, with regard to repeat-driven evolution. This study lays the groundwork for future genomic explorations on Hydnoraceae, as well as heterotrophic plants and their nuclear genome composition in general.

Aim: The pervasive impacts of climate change on the biodiversity and functionality in arid ecosystems are increasingly evident in the Anthropocene. Although soil microbes are anticipated to be sensitive to changes in precipitation regimes, the mechanisms through which multifaceted precipitation variances impair the current delivery of multiple functions by multitrophic microbiota remain largely unexplored. Here, we examined the direct effects of historical precipitation regimes on the multifunctionality and their indirect impacts mediated by soil microorganisms in drylands. Location: Northwestern China. Time period: Precipitation records (1979-2016); Field investigation in 2020. Major taxa studied: Multitrophic microbiota in biocrusts. Methods: We evaluated a 38-year daily precipitation across the arid regions to quantify its multifaceted characteristics, including mean amount, frequency, and variability. The community structures of heterotrophic bacteria, eukaryotic fungi, and photoautotrophic cyanobacteria were determined through amplicon sequencing, aimed to measure taxonomic and phylogenetic α-diversity, as well as spatial turnover in soil microbiota. We explored the interactive linkages between precipitation impacts and diversity effects on soil multifunctionality. Results: We found that α-richness exerted positive functional influences, but phylogenetic dissimilarity was a more important predictor in photoautotrophs. Species replacement, as a component of β-diversity, consistently enhanced the multifunctional dissimilarity and asynchrony of biocrusts. The legacy effect of historical precipitation variability, rather than annual precipitation, emerged as a primary driver on a convergence of less beneficial species, thereby promoting the variance in soil functioning. Importantly, the findings illuminated a cascading effect of precipitation regimes regulated by multifaceted diversity, which potentially magnifies their influences on vulnerable arid habitats. Main conclusions: Our study highlighted the importance of precipitation variability and the indirect climate impact via soil microbiota. It contributes to a deeper understanding of the real-world consequences of altered precipitation on drylands, providing valuable insights for more accurate modeling of global change.

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