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Phosphorus cycles of forest and upland grassland ecosystems and some effects of land management practices.

The distribution of phosphorus capital and net annual transfers of phosphorus between the major components of two unfertilized phosphorus-deficient UK ecosystems, an oak--ash woodland in the Lake District and an Agrostis-Festuca grassland in Snowdonia (both on acid brown-earth soils), have been estimted in terms of kg P ha--1. In both ecosystems less than 3% of the phosphorus, totalling 1890 kg P ha--1 and 3040 kg P ha--1 for the woodland and grassland, respectively, is contained in the living biomass and half that is below ground level. Nearly all the phosphorus is in the soil matrix. Although the biomass phosphorus is mostly in the vegetation, the soil fauna and vegetation is slower (25%) than in the grassland vegetatation (208%). More than 85% of the net annual vegetation uptake of phosphorus from the soil is returned to the soil, mainly in organic debris, which in the grassland ecosystem is more than twice as rich in phosphorus (0.125% P) as in the woodland ecosystem (0.053% P). These concentrations are related to the rates of turnover (input/P content) of phosphorus in the litter layer on the soil surface; it is faster in the grassland (460%) than in the woodland (144%). In both cycles plant uptake of phosphorus largely depends on the release of phosphorus through decomposition of the organic matter returned to soil. In both the woodland and the grassland, the amount of cycling phosphorus is potentially reduced by its immobilization in tree and sheep production and in undecomposed organic matter accumulating in soil. It is assumed that the reductions are counterbalanced by the replenishment of cycling phosphorus by (i) some mineralization of organically bound phosphorus in the mineral soil, (ii) the income in rainfall and aerosols not being effectively lost in soil drainage waters and (iii) rock weathering. The effects of the growth of conifers and sheep grazing on the balance between decomposition and accumulation of organic matter returned to soil are considered in relation to the rate of phosphorus cycling and the pedogenetic changes in soil phosphorus condition leading to reduced fertility. Although controlled sheep grazing speeds up phosphorus cycling and may reverse the pedogenetic trend in favour of soil improvement, conifers may slow down phosphorus cycling and promote the pedogenetic trend towards infertility.

Agriculture↗
PubMed2025

Phyllosphere microbiomes in grassland plants harbor a vast reservoir of novel antimicrobial peptides and biosynthetic diversity.

INTRODUCTION: The phyllosphere microorganisms colonizing plant surface harbor capacities to synthesize diverse specialized metabolites that mediate communication and interactions with environment and host. However, most known metabolites are derived from a few culturable microorganisms, and the genomic diversity and biosynthetic potential of the vast majority of bacteria associated with plants remain largely unexplored. OBJECTIVES: Here, we aim to explore the genome architecture, biosynthetic ability, and host specific adaptability of grassland ecosystems, uncovering new perspectives on grassland phyllosphere microbial resources. METHODS: We employed ultra-deep metagenomic sequencing, functional analysis, host-associated characterization, and bioactivity assays to explore the phyllosphere microbiome across 221 grassland plant samples representing 45 families. This approach revealed host preference in biosynthetic gene clusters (BGCs) and validated the antimicrobial efficacy of phyllosphere-derived antimicrobial peptides (AMPs). RESULTS: Grassland plant phyllosphere microbiomes encode diverse BGCs. We identified 885,396 potential AMPs from over 68 million non-redundant gene sequences. Then, we reconstructed hundreds of near-complete genomes from phyllosphere metagenomes, and 32.61 % of reconstructed genomes were identified as unclassified genomes, primarily within Pseudomonadota, Actinomycetota, Bacillota and Bacteroidota phyla. Of the near-complete genomes, 91.97 % of the BGCs and 99.76 % of the identified AMPs were previously uncharacterized. Host phylogenetic analysis revealed functional divergence. Poaceae-associated Pseudomonas genomes contain an average of 28 BGCs, significantly higher than those in Asteraceae-associated genomes (mean = 14.76, P = 0.033). Similarly, Poaceae-associated Pantoea genomes carried an average of 9 BGCs, exhibiting significant enrichment compared to genomes from Asteraceae (mean = 7.13, P = 6.1e-05), Lamiaceae (mean = 7, P = 0.015), Ranunculaceae (mean = 8.22, P = 0.0053), and Rosaceae (mean = 7.75, P = 0.00069). ParaFit analyses further confirmed that host phylogeny significantly structures microbial functional repertoires, with intra-family hosts sharing more KEGG pathways than inter-family hosts. These results suggest that host evolutionary relationships are associated with metabolic specialization in phyllosphere microbiomes. All 13 AMPs synthesized via solid-phase peptide synthesis demonstrated antimicrobial activity, inhibiting the growth of at least one tested bacterial strain. CONCLUSION: This study demonstrates the promise of grassland plant phyllosphere microbiome as a rich source for novel antimicrobial agents.

Antimicrobial Peptides↗
PubMed2026

Reduced legacy precipitation decreases microbial community growth efficiency and alters soil organic carbon in a California grassland.

BACKGROUND: Changes in global patterns can leave a lasting legacy in semiarid grasslands by reshaping microbial growth dynamics and carbon cycling during the first wet-up in the autumn-a period known for intense microbial activity and significant carbon emissions. To study the lasting impacts of decreased winter rain, we implemented two precipitation regimes (100% vs. 50% mean annual precipitation) in California Mediterranean-climate grassland field plots. After the dry season, soils were rewetted in the laboratory with H218O and sampled at 0 h, 3 h, 24 h, 48 h, 72 h, and 168 h post rewet. We quantified CO2 efflux, measured microbial growth and mortality via quantitative 18O stable isotope probing and 16S rRNA gene amplicon sequencing, and characterized the soil organic carbon chemical composition, metagenomes, and metatranscriptomes. RESULTS: We found that reduced winter precipitation imposed a strong legacy effect on microbial turnover; despite maintaining similar respiration rates, microbial growth declined by ~1 order of magnitude, yielding decreased community growth efficiency (CGE = new biomass growth/respiration), and microbial mortality declined by ~2 orders of magnitude. Soil organic carbon also shifted from lipid-like, amino-sugar-like, and protein-like compounds (indicative of microbial necromass) to more oxidized lignin-like and tannin-like compounds (indicative of decomposing plant-derived compounds). Meta-omics revealed distinct metabolic strategies linked to CGE. At high-CGE, microbes appeared to consume more energetically favorable N-rich necromass (released via high microbial turnover); this allowed for increased amino acids and peptidoglycan biosynthesis and greater aromatic compound degradation, fueling further energy production and growth efficiency. At low CGE, communities had elevated carbohydrate metabolism and lipid turnover, consistent with increased investment in plant detritus degradation and membrane repair and maintenance rather than growth. CONCLUSIONS: Together, our findings demonstrate that reduced winter rainfall decreases microbial turnover following rewetting without a concurrent reduction in CO2 emissions. This shift results in persistently lower CGE, which has the potential to increase soil carbon loss as CO2. If such conditions are maintained over multiple years, these changes could reshape soil organic carbon stocks and alter the balance of grassland ecosystems under future climate scenarios. While our data suggest that sustained reductions in CGE may drive SOC decline, the magnitude and persistence of these effects depend on long-term environmental dynamics and warrant further investigation. Video Abstract.

Soil Microbiology↗
PubMed2026

Increased precipitation decelerates temporal succession of grassland soil microbial communities.

Global precipitation regimes have been shifted in recent decades, imposing significant consequences in water-limited grassland ecosystems. However, the effects of increased precipitation on the succession of soil microbial communities remain unclear, mainly due to the scarcity of long-term experiments with time-series data. Here, we examined temporal succession of grassland soil microbial communities in a long-term increased precipitation experiment. Both soil microbial taxonomic and functional structures were significantly altered by increased precipitation. Increased precipitation significantly decelerated the succession rates of soil microbial functional structure (i.e. time-decay relationships). Consistent with the increased microbial decomposition and heterotrophic respiration, the abundances of soil microbial carbon decomposition genes were markedly enhanced by increased precipitation. Furthermore, increased precipitation stimulated genes involved in nutrient cycling processes, potentially promoting plant growth. Collectively, the contributions of stochastic processes in shaping microbial communities were increased under increased precipitation, suggesting that microbial successional trajectories may shift toward multiple alternative states characterized by greater stochasticity under future altered precipitation regimes.

Soil Microbiology↗
PubMed1977

Investigation on lichen production of grassland communities of sandy soil II.

Lichen production was investigated on two types of sandy Grasslands over more than two years. Two maxima of production were observed, a minor one in spring and a major one in autumn. The degree of these depended on climatic factors. Path analysis was applied for determining (1) the order of importance of the climatic factors and (2) the role of these factors in the changes of the total lichen production of associations and their influence on the productivity of the two determinant species, viz., Cladonia magyarica and Cl. furcata. Lichen production should be investigated for a period longer than the vegetation period.

Lichens↗
PubMed1979

[Theater nurse and midwife in Cameroon. Impressions and experiences in the grasslands (Northwest Cameroon) during a six-and-a-half month stay in a hospital situated at a height of 1800 m].

The author describes the circumstances of the hospital and out-of-hospital situation in the region she worked in, in focussing on the relevant practical features of the daily life of patients and staff. She deals among other things with the maternity ward (including the separate "camp" devoted to prenatal stays) and the operating theatre. As regards health activities outside the hospital, she mentions those of the existing health centres and of auxiliary personnel called first-aiders (whose job description is close to the one of the village health workers advocated by WHO and others). A health team, usually led by a physician, makes periodic visits to bush villages. The importance of the contacts thus created, for health work itself (including collaboration with traditional health practitioners) as well as for community development, is underlined.

Cameroon↗
PubMed1976

[Annual lipid cycle of the grassland Varanian lizard].

The circannual chronobiology of Varanus exanthematicus exanthematicus Bosc, lacertilian reptile of Senegal, is characterized by a period of rest from January to June (dry season) and a period of activity from July to December (wet season). The study of the lipids metabolism shows a two month deplacement period: as a matter of fact from November to April the lipogenesis prevails, while from May to October it is the lipolysis. These two phases correspond to the periodicity of the development of the gonads, which are at rest from November to April and in activity from May to October. The synchronism of the phases of lipolysis and of gonads muturation argues in favour of the lipids utilization for the growth of the gonads.

Adipose Tissue↗
PubMed2026

Extreme climatic events drive consistent and predictable shifts in soil antibiotic resistance genes.

Antimicrobial resistance (AMR) is a growing One Health challenge, and as climate warming intensifies extreme events, it remains unclear how these disturbances affect soil antibiotic resistance genes (ARGs). Here we analyzed the data from a controlled experiment using soils from 30 grassland sites across ten European countries, which simulated drought, flooding, freeze-thaw, and heatwaves to explore ARG dynamics. Overall, ARGs exhibited relatively small but highly consistent shifts across treatments. Heatwaves caused the strongest reductions in ARG abundance and in their linkages with mobile genetic elements (MGEs), a pattern that may reflect a hypothesized metabolic-genetic trade-off, in which microbial investment may shift from core metabolism toward stress signaling and structural maintenance. ARG dynamics during and after disturbance were governed by distinct soil physicochemical properties, with temperature and nutrient status determining acute responses, whereas soil moisture and seasonal variability in temperature and precipitation shaped longer-term legacy effects. Cross-validated random-forest models showed positive predictive performance for Bray-Curtis-based compositional responses within the environmental range represented by the 30 grassland sites. Our findings enhance the understanding of how soil ARGs respond to extreme climatic events and provide a step toward predicting extreme-event impacts on soil resistomes with relevance to One Health.

Soil Microbiology↗
PubMed1978

[On the distribution of myxobacteria in the temperate South America (author's transl)].

60 soil samples from Southern Chile, mainly from forests and grassland, yielded six species of myxobacteria. In forest soils Myxococcus coralloides and Myxococcus fulvus occur frequently, in grassland soils Myxococcus coralloides and Archangium gephyra are predominating. Myxococcus virescens, Melittangium lichenicola, and Cytobacter fuscus have been observed rarely. It is pointed out that due to climate factors a high soil acidity causes the low nuber of myxobacter species. A comparison with the number of species in substrates from important plant formations over various climates is given.

Chile↗
PubMed2025

Environmental Stresses Constrain Soil Microbial Community Functions by Regulating Deterministic Assembly and Niche Width.

Increasing evidence indicates that the loss of soil microbial α-diversity triggered by environmental stress negatively impacts microbial functions; however, the effects of microbial α-diversity on community functions under environmental stress are poorly understood. Here, we investigated the changes in bacterial and fungal α- diversity along gradients of five natural stressors (temperature, precipitation, plant diversity, soil organic C and pH) across 45 grasslands in China and evaluated their connection with microbial functional traits. By quantifying the five environmental stresses into an integrated stress index, we found that the bacterial and fungal α-diversity declined under high environmental stress across three soil layers (0-20 cm, 20-40 cm and 40-60 cm). Metagenomic-based analyses showed that the diversity of functional genes decreased along the stress gradients. High stress enhanced the abundance of genes associated with broad functional categories (e.g., glycolysis/gluconeogenesis, TCA cycle, DNA replication/repair and cell growth/death) but reduced the abundance of genes linked to specialised functional categories (e.g., C, N, S and methane metabolism). Phylogenetic null models and niche analyses indicated that stochastic assembly processes predominated in high-diversity communities, in which bacterial and fungal taxa had a narrow ecological niche. However, in low-diversity communities, deterministic assembly processes were dominant, and taxa had wide niches, correlating with the reduction in gene abundance observed for broad and specialised functional categories. Given the essential role of the microbiome in regulating ecosystem functions, our findings suggest that low-diversity-induced deterministic community assembly processes and a wide niche under high environmental stress may regulate microbial functions. These findings emphasise the ecological mechanisms through which microbial biodiversity regulates terrestrial ecosystem functioning.

Soil Microbiology↗
PubMed2024

Land use conversion to uplands significantly increased the risk of antibiotic resistance genes in estuary area.

Land use conversion in estuary wetlands may affect the transmission of antibiotic resistance genes (ARGs), while the risk rank of the ARGs and the change of clinically relevant ARGs under various land-use types are not well understood. This study used metagenomics to reveal the diversity and abundance of ARGs across five distinct land uses: reed wetland, tidal flat, grassland, agricultural land and fallow land, as well as their distribution and potential health risks. Results showed that high numbers of ARG subtypes and classes were detected irrespective of land-use types, notably higher in agricultural land (144 ARG subtypes). The most shared ARG subtypes were multidrug resistance genes across all the land uses (29 subtypes, 4.7 × 10-2-1.5 × 10-1 copies per 16S rRNA gene copy). Proteobacteria and Actinobacteria were primary ARG hosts, with 18 and 15 ARGs were found in both of them, respectively. The ARG subtype mdtB was the most dominant clinical ARG detected with 90 % amino acid identity. The change of ARGs exhibited a consistent trend across land uses in terms of health risk ranks, with the highest observed in fallow land and the lowest in reed wetland. This study reveals the distribution pattern of ARGs across various land-use types, and enhances our understanding of the potential health risks associated with ARGs in the context of coastal wetland conversion in estuary areas.

Estuaries↗
PubMed2026

Nuclear single-copy orthologous genes as phylogenomic markers for resolving the closely related firefly genera Pteroptyx, Medeopteryx, and Trisinuata (Coleoptera: Lampyridae: Luciolinae).

Fireflies (Lampyridae) are bioluminescent beetles with broad ecological roles across temperate and tropical ecosystems, occupying diverse habitats including forests, wetlands, grasslands, mangroves, and riverine systems. The subfamily Luciolinae is primarily distributed across Asia and the Indo-Pacific. Phylogenetic relationships among three closely related Luciolinae genera - Medeopteryx, Pteroptyx, and Trisinuata - remain unresolved using mitochondrial genome data alone. This study used nuclear genome data to resolve relationships among these genera and identify a lighter-weight nuclear marker panel for expanding taxon sampling. Draft genomes were reconstructed for fifteen firefly species, eight from the focal genera, and analyzed with five published firefly genomes. Using BUSCO and OrthoFinder, 1,011 nuclear single-copy orthologs (SCOs) were identified for phylogenomic inference. Discordance between concatenation- and coalescence-based phylogenies indicated incomplete lineage sorting (ILS). The coalescence-based phylogeny recoveredPteroptyxas monophyletic and sister to a (Medeopteryx,Trisinuata) clade, with Trisinuata nested within a non-monophyletic Medeopteryx; however, quartet support at the base of Pteroptyx, particularly at Pt. valida, was low.Filtering for compositional homogeneity, clock-likeness, and species-tree concordance yielded 103 SCOs with a significantly higher proportion of parsimony-informative sites than non-selected loci, retaining the backbone topology with higher gene concordance support at scored clades, while ILS-driven discordance at Pt. valida persists - confirming that the reduced panel retains phylogenetic resolving power for future taxon sampling. These findings demonstrate a practical framework for using nuclear SCOs to resolve close phylogenetic relationships within Luciolinae. Future work should expand taxon sampling - especially forTrisinuata - alongside long-read assemblies, for a more robust phylogenomic framework.

Fireflies↗
PubMed1975

Observations on the epidemiology of ephemeral fever in Kenya.

Ephemeral fever antibody was found in domestic cattle in Kenya across a wide range of ecological zones, from highland forests and grasslands to desert and semidesert thorn scrub. Antibody was found in several species of game animals, notably waterbuck and buffalo, where over 50% of the samples showed antibody to EF. Evidence was obtained to show that the virus had been cycling in these wild ruminant populations between epizootics in domestic cattle.

Animals↗
PubMed1975

Feedback dynamics analysis of secondary successional transients in ecosystems.

A theoretical dynamic model of the mutual causalities that generate secondary successional behavior in ecological systems is developed using zero- and first-order nonlinear difference equations. The model is based on Odum's tabular model of ecological succession, and has been simulation-tested for the case of secondary succession in a grassland ecosystem. It shows how energy, abiotic and biotic matter, and community (species) diversity interact in time and space to produce autogenic succession, that is, developmental changes generated by biotic components within the system as distinguished from allogenic forcing functions from without the system. The simulations demonstrate that successional transients can arise from the endogenous feedback structure of the ecosystem and provide strong evidence for the validity of the model.

Animals↗
PubMed2026

Isolation and global occurrence of nitrogen-fixing Acidobacteriota in soil environments.

Acidobacteriota, one of the most abundant and ubiquitous bacterial phyla in soils, are well recognized for their role in carbon cycling. In contrast, their roles in soil nitrogen cycling remain largely unexplored, although recent metagenome-assembled genome (MAG) analyses suggest that Acidobacteriota may harbor genes involved in nitrogen cycling. Here, we provide culture-based evidence of diazotrophy within this phylum and demonstrate the widespread occurrence of nitrogen-fixing Acidobacteriota across diverse soil types. From grassland and agricultural soils, we isolated five Acidobacteriota strains representing novel taxonomic lineages, four of which harbor functional nitrogenase (nif) gene clusters. These strains were capable of fixing atmospheric nitrogen in vitro and/or in soil microcosms, as evidenced by acetylene reduction, N2-dependent growth, transcription of nif genes, incorporation of 15N into biomass and soil, and inhibition of nitrogenase activity by ammonium. Furthermore, global-scale meta-analysis of soil metagenomes revealed that nif-harboring Acidobacteriota are widely distributed and locally dominant across soil types. These results demonstrate the nitrogen-fixing capability of Acidobacteriota at the organismal level, complementing MAG-based inferences, and underscore their adaptive capacity in nitrogen-limited environments and their potential contribution to terrestrial nitrogen fixation. We also propose novel taxa within the class Terriglobia of the phylum Acidobacteriota, including diazotrophic strains, comprising one novel family, three novel genera, and four novel species: Koromonadaceae fam. nov., Koromonas soli gen. nov., sp. nov., Koromonas humicola sp. nov., Oryzophilus luti gen. nov., sp. nov., and Humiphilus diazotrophicus gen. nov., sp. nov.

Soil Microbiology↗