Agriculture, Ecosystems & Environment

The persistence of specialised survival spores produced by microbial pathogens represents a primary bottleneck in the management of plant diseases. In oomycetes, these spores (known as oospores) are largely impervious to chemical control, allowing them to persist in soil and initiate new infection cycles over many years. A prominent example is the soil-borne pathogen Phytophthora agathidicida, the causal agent of kauri dieback disease, where long-lived oospores hinder conservation efforts in native forests. The resilience of oospores is attributed to their thick wall composed of complex {beta}-glucan layers that render the oospores impermeable to most conventional biocides. Here we have investigated an enzyme-based approach for weakening the oospore cell wall. We searched enzyme databases to select {beta}-glucanases targeting a variety of linkages found in Phytophthora oospore walls. Eight of these {beta}-glucanases were successfully purified and tested for their digestive activity against intact oospores in vitro using a phenol-sulfuric acid assay. We showed that combining these enzymes was crucial to achieve significant digestion through synergies and additive effects. The optimal combination, comprising 1,3-, 1,6-, and 1,3(4)-{beta}-glucanases, was evaluated for its ability to permeabilise oospores to five biocides typically effective only on other, more sensitive lifecycle stages of the pathogen. Using a live/dead fluorescence assay, we observed that the effects of the membrane-targeting biocides were potentiated in oospores that were pre-treated with the {beta}-glucanase mixture. Our results highlight enzymatic cell wall permeabilisation as a promising strategy toward improved management of oospore persistence in kauri forest soils and against broader oomycete threats. KeypointsO_LIOur phenol-sulfuric acid assay can be used to screen for oospore-degrading enzymes. C_LIO_LISynergistic enzyme combinations are essential for effective oospore wall digestion. C_LIO_LIEnzyme pre-treatment sensitises oospores to membrane-targeting biocides. C_LI

Subsistence agriculture in sub-Saharan Africa faces persistent productivity challenges due to low soil fertility, limited inputs, and increasing climate variability. Agroforestry can offer a sustainable strategy for smallholder systems by enhancing soil quality and the presence of arbuscular mycorrhizal fungi (AMF) in crop roots. Using a canopy-based radial sampling design, we assessed the influence of Mangifera indica (mango) trees on soil properties and AMF communities in maize and cassava in southern Ethiopia. Illumina MiSeq sequencing identified 908 AMF operational taxonomic units (OTUs) from 7 families, dominated by Glomeraceae. While soil properties, including pH, total nitrogen (TN), organic carbon, and potassium, were significantly affected by the distance from mango trunks, this was not the case for AMF community composition and AMF richness and diversity. Host identity, rather than distance from the mango trees, was the primary driver of AMF community composition, with distinct and host-specific assemblages in mango, maize, and cassava roots. Soil nutrients influenced AMF diversity differently across hosts. In maize-mango systems, TN positively affected observed richness (Sobs) and Shannon diversity (N1), whereas Olsen P negatively affected N1 and Simpson diversity (N2). In cassava-mango systems, TN enhanced Sobs, and Olsen P positively influenced expected richness (Sexp). Overall, these findings demonstrate a decoupling between mango-induced soil fertility enhancement and crop AMF community composition and diversity, rather emphasizing the roles of host type and soil nutrients in structuring AMF communities. Without demonstrating direct benefits, we at least show that mango can be effectively integrated into smallholder maize and cassava production without compromising the AMF communities, while enhancing key soil fertility indicators. Maintaining adequate nitrogen levels while avoiding excessive phosphorus inputs may help sustain stable AMF communities in agroforestry systems.

QuestionsEcological monitoring, repeated collection of ecological data, is essential to document how ecosystems respond to change. In grasslands, different vegetation monitoring protocols are used across disciplines, making it difficult to address multiple management objectives or research questions. We asked four questions about how three common vegetation monitoring protocols compare. (1) How do the protocols differ in how they collect data? (2) How do the protocols differ in their utility? (3) In what ways do vegetation measurements quantitatively differ across protocols? (4) What are each protocols strengths? LocationThis study was conducted on working ranches in the Southern Great Plains with vegetation consisting mainly of native forbs and grasses. MethodsWe implemented three protocols at each site: (1) the Rangeland Analysis Platform (RAP), (2) the Grassland Effectiveness Monitoring (GEM) protocol, and (3) a typical pollinator ecology survey protocol. We qualitatively compared each protocols utility and quantitatively compared cover measurements that each produced. ResultsAll three protocols displayed positive associations within cover categories, but differed in actual cover measurements. The RAP protocol, which uses remote sensing, measured the highest total vegetation cover. The GEM protocol, a line-point intercept method, had more capability to capture fine-scale cover patterns. The GEM protocol measured the most bare ground while the Pollinator protocol measured more forb coverage. ConclusionFine-scale methods like the GEM protocol are most appropriate to address objectives that require capturing small patterns that would otherwise be overlooked with methods like quadrats or remote sensing. Remote sensing is advantageous when monitoring large areas or inaccessible land, but may over-estimate cover. The Pollinator protocol is best equipped to address questions regarding flower abundance and richness. Similarities among protocols can facilitate synergy across disciplines for more effective monitoring. We emphasize the importance of denoting a clear scale and scope of monitoring objectives before selecting methods.

Recovery debt (RD) quantifies the interim deficit of biodiversity and function during the recovery process after disturbance. Unlike typical recovery indices derived from data on experimental-control comparisons, RD further considers the target (reference) biodiversity level, modelling the rate at which it is approached over time. However, the application of the RD approach to active restoration has not been explicitly implemented to date. Here, we extend the RD framework to evaluate active ecological restoration in agricultural systems, defining the onset of recovery as the shift from intensive to wildlife-friendly management. We applied this approach to assess short-term pollinator recovery in 14 olive groves across a gradient of farming intensification and landscape complexity in southern Spain. Restoration actions included adopting low-intensity ground cover management and actively restoring field margins. At one, three, and five years post-restoration, we assessed community responses by quantifying bee abundance, species richness, plant-bee network properties, and flower visitation rates. Reference systems were defined by olive groves in complex landscapes with low-intensity herb cover management and organic farming practices. Following restoration, the RD of bee abundance decreased from 71% to 55%. We found no significant effects of pre-intervention agricultural management on RD. Instead, across sites, the reduction of the RD (i.e., recovery) of bee abundance, richness, network connectance and flower visitation rate was strongly mediated by the availability of high-quality semi-natural areas in the surrounding landscape and by the ecological contrast created by restoration interventions at both the farm and floral patch levels. RD for other network metrics showed no significant pattern of variation. Our study demonstrates that wildlife-friendly management and targeted habitat restoration can rapidly reduce recovery debt for bee abundance and function in permanent agroecosystems. However, the recovery of more complex interaction-network properties likely requires longer timescales.

The effects of the selection of livestock type (e.g., sheep or cattle) and grazing intensity on the soil seed bank of sand grasslands of conservation interest were studied. 25 grazed grassland sites classified into four grazing intensity categories were studied. The soil seed bank was analysed by seedling emergence; germinated seedlings were classified into morpho-functional, social behaviour type (SBT) and CSR strategy groups. The following hypotheses were tested: i) Diversity and density of soil seed banks are lower in sheep-grazed sites than in cattle-grazed ones. ii) The species composition, diversity, and density of the soil seed banks are more strongly affected by grazing intensity than by the livestock type. iii) Leaf traits, SBT and CSR strategy composition are highly affected both by livestock type and grazing intensity. The main effect of livestock type only affected seed bank density, while that of grazing intensity had a significant effect on most of the variables. Most of the studied variables were affected by the interaction of grazing intensity and livestock type. Total seed bank density was lower at all grazing intensity levels in sheep-grazed sites than in cattle-grazed ones, especially close to frequently visited places. We found that sheep grazing sustained a much lower total seed bank density and lower density of species of natural and semi-natural habitats regardless to the grazing intensity. Thus, livestock type must be carefully selected and high-intensity sheep grazing should be avoided in the long-run when managing sand grasslands. HighlightsO_LIThe soil seed banks of sheep and cattle grazed sand grassland were studied C_LIO_LIEffect of grazing intensity found the most important driver of seed bank diversity and density C_LIO_LIThe total soil seed bank density was higher in cattle than sheep grazed sites C_LIO_LIBoth intensity and livestock type must be considered in the grassland management planning C_LIO_LIHigh intensity sheep grazing should be avoided in sand grassland management C_LI

Decomposition of organic matter is a key process in soils contributing to carbon and nutrient cycling. To identify management strategies for agroecosystems that reduce nutrient losses while maximizing plant growth, it is important to understand which parameters determine decomposition rates. This study therefore investigated how the presence of winter wheat (Triticum aestivum var. Asory) affects decomposition in a controlled Ecotron setup with two soil types with varying organic matter content across three simulated climates (2013, 2068, 2085). Using the tea bag index, interstitial soil pore water analyses, microbial biomass quantification, bacterial and fungal gene abundance, and soil respiration measurements, we tested the hypotheses that plant exudates would enhance decomposition rate and microbial biomass, while plant nitrogen uptake would deplete soil nitrate, potentially mitigated by fertilization. Contrary to expectations, decomposition rates were lower in planted than in unplanted soils, suggesting resource competition between plants and microbes. No significant differences were observed in microbial biomass or respiration due to plant presence, and fertilization effects on nitrate or microbial mineralization were undetectable, likely due to rapid turnover of organic molecules including uptake by plants and microbes. Mechanistically, fungi and soil humidity were more important for decomposition than bacteria or temperature. The findings corroborate climate impacts on decomposition but also indicate microbial resilience and highlight the potential of management strategies like cover crops, adjusted planting dates and crop residual management which can contribute to healthy soils by sustaining carbon and nutrient cycling.

O_LIPlants take up nutrients from the soil while investing in absorptive root surface or mycorrhizal partners. Root hairs - a major structure for nutrient uptake and cheap to build - increase the absorptive root surface. As such they are an important component of plant resource economics but largely neglected in root economic concepts so far. C_LIO_LIThis is mainly due to data scarcity, which we set out to overcome by measuring root-hair traits on 82 European grassland species in a greenhouse experiment. Using fluorescence and light microscopy, root-hair length and incidence was measured along with mycorrhizal colonization. C_LIO_LIWe found a phylogenetically conserved trade-off between plant investment into root hairs and mycorrhiza. A similar trade-off between root-hair incidence and mycorrhiza occurred at the intraspecific level, while patterns were heterogeneous among species. Plant species with high colonization rates showed the highest variability in root-hair incidence. C_LIO_LIWe conclude that plants vary along a gradient ranging from investment into root hairs as part of a "do-it-yourself" strategy to collaboration with mycorrhizal fungi while showing intraspecific variation in root-hair incidence. These findings demonstrate that root hairs play a fundamental role in fine-root trait variation and need to be considered when studying belowground plant economic strategies. C_LI

Habitat modification is a major driver of avian population change in tropical savanna ecosystems. This study investigated habitat-related variation in the abundance of the Red-cheeked Cordon-bleu (Uraeginthus bengalus) across human settlements and surrounding farmlands in Laminga Village, Jos-East Local Government Area, Plateau State, Nigeria. Field surveys were conducted over a three-week period in November 2024 using 21 line transects sampled during peak bird activity periods. Bird abundance data were analysed using a Poisson Generalized Linear Model (GLM). Results showed that habitat type significantly influenced abundance, with significantly lower abundance recorded in human settlements compared to farmlands ({beta} = -0.836, SE = 0.192, z = -4.359, p < 0.001). Transect length positively influenced abundance ({beta} = 0.028, SE = 0.008, z = 3.600, p < 0.001). Model performance improved substantially from the null deviance (159.88) to the residual deviance (125.85), with an Akaike Information Criterion (AIC) value of 306.32. The findings suggest that farmlands provide more favourable habitat conditions for the species, likely due to greater vegetation availability and reduced structural disturbance relative to settlement areas. The study highlights the ecological importance of low-intensity agricultural landscapes in supporting avian persistence within human-modified savanna environments.

Microbial communities can shift under drought in ways that enhance plant performance during drought ("microbe-mediated acclimation"). However, it is also possible for microbial communities to shift in ways that worsen the effects of drought ("mal-acclimation"). It is unclear how and where microbe-mediated acclimation vs. mal-acclimation occurs, or if there are types of soils or microbial communities that are more likely to harbor microbes that enhance plant acclimation and limit mal-acclimation. We tested for microbe-mediated plant acclimation/mal-acclimation to drought in soils from 21 maize farms in the midwestern United States, spanning a range of climate, soil types, and management practices. We first conditioned soil microbial communities to drought vs. well-watered conditions in a greenhouse and then tested for microbe-mediated acclimation by growing maize in soils inoculated with the conditioned microbial communities under drought and well-watered conditions. Drought-conditioned soils did not enhance plant performance under drought. In fact, one third of the farms exhibited mal-acclimation, especially under well-watered conditions where wet-conditioned soils reduced plant performance in well-watered contemporary conditions. Farm management practices, climate, soil texture, and microbial diversity generally did not predict when this microbe-mediated mal-acclimation occurred. Overall, these results suggest that in agricultural soils, microbes may frequently impede-rather than facilitate-plant acclimation to soil moisture levels. Open research statementThe plant and soil data used in this study are available via the Environmental Data Initiative repository at https://doi.org/10.6073/pasta/f4a0db3a076cf6d8cef908947f82736e. The bacterial and fungal amplicon sequence data are available via the European Nucleotide Archive under accessions PRJEB110071 and PRJEB109827, respectively.

IntroductionHuman land-use intensification and the resulting habitat loss are primary drivers of insect pollinator declines. Habitat restoration offers a promising approach to counteract these declines, yet landscape-level evaluations of bee responses to restoration and management remain limited. We conducted a two-year, landscape-scale study in Wisconsin, USA, to assess how different intensities of tallgrass prairie restoration and management affect bumble bees (Bombus spp.). ObjectivesThis study aimed to determine whether (1) bumble bee abundance and diversity increase with assisted restoration, and (2) outcomes differ between low-(seeded only) and moderate-intensity (seeded and managed with prescribed fire) interventions. MethodsUsing catch-and-release surveys, we measured bumble bee abundance and diversity at 32 sites representing a gradient in restoration intervention: no intervention (unassisted recovery), low intervention, and moderate intervention. ResultsBumble bee abundance and diversity were higher at assisted restoration sites (low and moderate intervention) than at unassisted sites. Although both tended to be greater at moderate than low intervention intensities, these differences were not statistically significant. Bumble bee community composition also differed across intervention intensity, driven by shifts in dominant species (e.g., B. impatiens and B. griseocollis). Rarer taxa, including endangered and vulnerable species, occurred only at assisted restoration sites, with the largest populations at moderate intervention sites. Across all sites, bumble bee responses were strongly and positively associated with floral abundance, but not with semi-natural habitat in the surrounding landscape. ConclusionOur findings demonstrate that assisted grassland restoration can effectively increase bumble bee abundance and diversity, supporting its value as a conservation practice for pollinators. Implications for Practice: (1) Grassland restorations targeting plant communities can successfully support nontarget pollinators across a range of management intensities and landscape contexts. Adding seeds of pollinator-preferred plants could improve restorations with low floral abundance and diversity. (2) Management of existing restorations is important to maintain abundant floral resources and diverse pollinator communities. Because sites varied widely in prescribed fire use, our findings likely represent a conservative estimate of its benefits, and higher intervention intensity (e.g., repeated seeding, regular fire, mechanical or chemical shrub and invasive plants control) may further enhance outcomes for bumble bees.

IntroductionThe environmental impacts of pesticides have raised increasing concern, prompting the development of indicators to assess associated risks across ecosystems. Two main categories are generally distinguished: score-based indicators, which aggregate variables into scores, and risk-based indicators, grounded in the definition of risk as the product of hazard and exposure. Although more data-intensive and more complex to implement, risk-based indicators are recognized to better preserve proportionality with actual risk levels. ObjectivesThis study presents Phytorisque, a model based on the exposure-toxicity ratio to monitor risks associated with pesticide use in Walloon agriculture, from farm to regional scales, and to identify the most contributing active substances in support of risk-reduction policies MethodPhytorisque is a hybrid model that combines mechanistic, empirical, and statistical approaches, integrating quantities of active substances, their ecotoxicological characteristics, and their mobility, persistence, and bioaccumulation properties to generate indices specific to different environmental compartments. ResultsThe indices obtained enable comparison across substances, agricultural sectors, years, and management scenarios. The Phytorisque model provides an integrated assessment of risk across environmental compartments. It can monitor risk evolution over the years for policy impacts evaluation, diagnose the most problematic substances and prospect environmental risks associated with the use of chemical phytoproducts. ConclusionsPhytorisque provides an integrated risk assessment approach adapted to temporal monitoring, diagnosis, and forecasting. It is a relevant operational tool for supporting regional strategies aimed at reducing pesticide-related risks. The model is also transferable to other regions through the adaptation of parameters to local conditions and context.

AimOur aim was to study the effects of energy availability and landscape habitat heterogeneity on bird taxonomic and functional gamma-diversity and propose conservation guidelines based on the results. LocationSouthern and Central Finland Time Period2009-2020 Major Taxa StudiedBirds MethodsWe derived biodiversity variables from bird monitoring line transects to assess the effects of latitude, longitude, and landscape composition, configuration, and heterogeneity at multiple spatial scales: 100, 500, 2,000, and 5,000 m. We tested the effects of these landscape metrics on the total community, bird ecological guilds (species richness and abundance), functional diversity, and overall species specialization index. ResultsWe found clear evidence supporting a positive effect of energy (latitude and soil fertility) and habitat amount on bird abundances. Our results also revealed a northward increasing trend in functional diversity and species specialization. Habitat heterogeneity positively affected both bird abundance and species richness. Heterogeneity of land cover types was shown to promote abundances, while functional measure of landscape heterogeneity was positively connected to species richness. Land use with high anthropogenic activities, such as urban areas and cropland, negatively affected forest specialists and species sensitive to human activities. Main ConclusionsEnergy and habitat heterogeneity and amount are major mutually nonexclusive factors shaping bird communities in Finnish landscapes. Nonetheless, certain land use types favour some guilds while excluding others (for example, urbanized areas or cropland favouring open area species while excluding old-growth forest specialists), showing that biodiversity conservation is a matter of specialized landscapes. Furthermore, different measures of landscape heterogeneity demonstrated positive relationships with the studied bird guilds, highlighting the consistency of the species-heterogeneity relationship.

Understanding how anthropogenic disturbance and vegetation structure influence bird abundance is important for biodiversity conservation in rapidly changing tropical landscapes. This study evaluated the effects of anthropogenic and vegetation-related variables on the abundance of the Red-cheeked Cordon-bleu (Uraeginthus bengalus) in human settlements and surrounding farmlands in Laminga Village, Jos-East Local Government Area, Plateau State, Nigeria. Bird surveys were conducted using line transects and quadrat-based vegetation assessments during November 2024. Poisson Generalized Linear Models (GLMs) were used to examine the influence of anthropogenic and vegetation predictors on abundance. Among anthropogenic variables, building density significantly reduced abundance ({beta} = -0.141, SE = 0.060, z = -2.333, p = 0.020), whereas human presence ({beta} = -0.073, p = 0.141) and noise level ({beta} = 0.009, p = 0.592) did not significantly influence abundance. Average grass height showed a marginal positive relationship with abundance ({beta} = 2.008, SE = 1.051, z = 1.910, p = 0.056), while hedgerow presence, hedgerow height, grass cover, and bare ground cover were not significant predictors. The vegetation model produced the lowest residual deviance (91.19) and AIC value (297.66), indicating comparatively stronger explanatory performance. The results suggest that structural habitat characteristics and building density may play more important roles in shaping Red-cheeked Cordon-bleu abundance than human activity or noise levels alone. These findings provide insight into species responses to environmental disturbance in human-modified savanna ecosystems.

Soil salinity and sodicity are among the major challenges threatening agricultural productivity in the Central Rift Valley of Ethiopia. A column experiment was conducted in laboratory on saline-sodic soils of Metehara Sugar Estate to evaluate the effectiveness of phosphogypsum and leaching in reclaiming these soils. The treatments comprised of five rates of phosphogypsum equivalent to 50, 75, 100, 150, and 200% gypsum requirement, 100% gypsum requirement of natural gypsum, and an absolute control with no amendments applied, and five volumes of leaching water. The treatments were arranged in Complete Randomized Design with three replications. The leaching water was applied to the columns in an intermittent ponding mode. Leachates and soil samples collected from the columns after termination of the leaching process were analyzed for selected soil properties. Results showed that applying phosphogypsum at a rate of 100% gypsum requirement or higher (which is equivalent to [&ge;] 13 tons/ha) along with 3-4 pore volume of leaching water was found to be the most effective combination to reduce salinity and sodicity to levels that are suitable for most crops (ECe <4 dS/m and ESP < 10%,). The efficiency of phosphogypsum equivalent to 200% gypsum requirement was 81% and 75% in soluble salt removal and Na reduction, respectively. Results of the study suggest that phosphogypsum is a promising reclamation material for saline-sodic soils. However, a field experiment has to be conducted to evaluate the effectiveness of these amendments under natural conditions and come-up with implementable rate recommendations.

The increasing use of microbial biopesticides in sustainable agriculture requires a deeper understanding of their potential impact on non-target pollinators. Although biocontrol agents are generally considered safer than synthetic pesticides, they may still cause subtle but ecologically relevant adverse effects on non-target organisms, especially when exposed to multiple stressors that are often overlooked in current risk assessment frameworks. Among these, nutritional stress, caused by habitat loss, fragmentation and reduced floral diversity, is becoming increasingly widespread. In this study, we investigated the lethal and sublethal effects of the bacterial biopesticide Bacillus velezensis (formerly B. amyloliquefaciens) strain QST713 at field-relevant concentrations on two key pollinators: Apis mellifera and Bombus terrestris. For the first time for a biopesticide, oral toxicity was assessed under environmental stress represented by diets with varying sugar concentrations (optimal and suboptimal) to identify potential synergistic effects on bee health. Sublethal effects were examined by studying learning performance and memory retention through a conditioning experiment under laboratory conditions. The results showed marked species-specific differences. While B. velezensis did not impact bee survival under realistic nutritional conditions, we observed a synergistic lethal effect in B. terrestris when biopesticide exposure was coupled with extreme nutritional stress (sugar deprivation). Similar species-specific differences emerged at the behavioral level: unlike A. mellifera, B. terrestris showed impaired visual learning and early long-term memory recall. Taken together, these results show that sublethal cognitive endpoints and multi-stressor contexts may reveal vulnerabilities not immediately evident through mortality-based assessments alone. Our findings also highlight the importance of including multiple pollinator species in risk assessment, as sensitivity to biopesticides might greatly vary among species.

Early management decisions in operational forestry are critical for plantation success because it strongly influences seedling quality at planting. Beyond shaping seedling morphology, nursery inputs can also restructure root-associated fungal communities which has consequences for nutrient acquisition, stress tolerance and disease suppression after planting. In this study, we altered nutrient and fungicide inputs based on mycorrhizal ecological theory and quantified the effects of these treatments on key dimensions of the growth performance of radiata pine seedlings. In parallel, we profiled the root-associated mycobiome, assigning fungal taxa to functional guilds and summarizing their richness, diversity, relative abundance and community structure. Using a composite performance index that integrates the key morphological and health measures into a single response variable, together with conventional statistical models with machine learning approaches, we identified management practises that promote both plant performance and a favourable root fungal community and determined the consistent microbiome changes linked to overall quality of the seedlings. These results suggest that microbial feedback loops occur even in highly managed nursery conditions. More broadly, by combining a composite performance index with predictive modelling, we provide a practical way to test complex management combinations and identify microbiome features associated with high-quality planting stock.

Background and AimsPlants deploy triterpenoid saponins as chemical defences against herbivores, yet it remains unclear whether insect digestion detoxifies these compounds or generates equally or more active metabolites. Because saponin bioactivity depends strongly on glycosylation patterns, we examined the fate and defensive activity of hederagenin-derived saponins during herbivory. MethodsLarvae of Plutella xylostella were fed leaf discs containing structurally defined hederagenin-derived saponins. Saponin composition in treated leaves and larval frass was analysed by LC- qTOF-ESI-MS/MS. Feeding assays were used to compare the antifeedant activity of mono- and bidesmosidic forms. Key ResultsLarvae selectively metabolized complex hederagenin-derived saponins into simpler forms, with cellobiosides converted into monoglucosides during digestion, resulting in a marked shift in saponin composition between ingested material and frass. Feeding assays showed that monodesmosidic saponins strongly deterrer feeding, whereas bidesmosidic saponins were largely inactive. The loss of activity in bidesmosidic saponins was not explained by differential metabolism, indicating that glycosylation patterns directly determine biological function. ConclusionsInsect herbivores selectively modify saponin structures through deglycosylation, thereby altering their defensive properties. Our findings demonstrate that glycosylation governs both saponin activity and metabolic fate, highlighting insect-driven turnover as a critical component of plant chemical defence during plant-herbivore interactions. Issue SectionOriginal article

O_LIA productivity-driven higher nutrient demand of trees in diverse mixtures is frequently reported. Yet, it remains unclear how tree diversity influences microorganisms-plants interactions, in which microbes facilitate tree nutrient acquisition in exchange for carbon (C) to meet the resource demand of both. C_LIO_LIUsing a long-term tree diversity experiment in the subtropics, we assessed microbial investment in C-, nitrogen (N)-, and phosphorus (P)-acquiring enzymes in litter and mineral soil, testing the effects of tree species richness and mycorrhizal type (arbuscular (AM)- vs. ectomycorrhizal (EcM)-associated tree species). C_LIO_LIWith increasing tree species richness, microbial investment in C acquisition decreased, while investment in N and/or P acquisition increased in litter and in mineral soil. In mineral soil of AM-associated tree mixtures, ecoenzymatic stoichiometry revealed a shift from microbial investment in C toward P acquisition as tree species richness increased. C_LIO_LIOur findings suggest that tree diversity strengthens microbe-tree interactions in terms of C-for-nutrient exchange. This highlights the key role of soil microorganisms, particularly in AM symbiosis, shaping tree diversity-biogeochemical feedbacks. C_LI

Ectomycorrhizal (EcM) fungi are well-recognized symbionts impacting tree health and ecosystem functioning globally, yet understanding of their timing of proliferation in soils across seasons and years remains limited. We analyzed monthly patterns of EcM fungal abundance and community structure over two years in five temperate monodominant forest plots via quantitative PCR and Illumina sequencing. We found that the phenological dynamics of EcM fungi differed significantly by host tree leaf habit, fungal exploration type, fungal genus, and soil moisture. Overall, total EcM fungal abundances based on qPCR consistently peaked in autumn, and were more dynamic in evergreen than deciduous plots, supporting ideas of surplus carbon and asymmetric above-belowground dynamics. Longer-distance exploration types peaked earlier and were more stable than shorter-distance types, suggesting an independent and supportive role in releasing spring nutrients. About half of 20 focal taxa consistently peaked in either autumn, summer, or spring, while others were either host- and/or year-dependent. Our findings highlight that phenology is a key EcM fungal trait best explained by both host and fungal contributions, and future studies across biomes should consider seasonal shifts and sampling to elucidate phenological traits. Summary- The timing of belowground production and seasonal community dynamics remain poorly understood for ectomycorrhizal (EcM) fungi. - We collected soils monthly for two years from five temperate monodominant forest plots. - Fungal production peaked in autumn, shorter-distance and evergreen-associated spanned wider ranges, and half of focal fungal genera showed seasonal preference, emphasizing autumn surplus carbon and spring nutrients from long-distance types. - Future studies should consider seasonal shifts when sampling EcM fungal communities, and forest carbon models should include asymmetric above-belowground phenology. Translated Summary (Spanish)- La fenologia de la produccion y composicion de comunidades de hongos ectomicorrizicos (EcM) es poco estudiada. - Recolectamos suelos mensualmente por dos anos de cinco parcelas mono-dominantes templados. - Produccion maxima de hongos ocurrio en otono, hongos asociados con arboles siempreverdes y de exploracion de corta-distancia observaron rangos mas amplios, y la mitad de generos de hongos focales observaron preferencia estacional, enfatizando extra carbono en otono y nutrientes en primavera de tipos larga-distancia. - Estudios deben considerar cambios estacionales para el muestreo de hongos EcM, y modelos de carbono deben incluir fenologia asimetrica entre hojas y hongos. Plain language summaryEctomycorrhizal fungi are critical for the global carbon cycle, but their seasonal and inter-annual growth patterns remain unclear. We sample soil DNA monthly over two years across five different monodominant temperate forest stands. We find an overall belowground peak in autumn, with significantly later growth under wetter conditions, more dynamism with evergreen trees, and distinct spring growth by longer-distance fungi.

Urban pollinator gardens can provide refugia and support diverse populations of native bees amid threats from habitat destruction, pesticides, and potential ecological pressures from the introduced honey bee (Apis mellifera (Linnaeus, 1748)). The University of California, Berkeley, maintained a native bee garden at the Oxford Tract research facility to study the biodiversity, phenology, and foraging habits of urban bees from 2003 to 2009. That garden was decommissioned, and a new garden was re-established in 2019. Using diversity observations from the early 2000s garden and non-lethal sampling techniques, we characterized plant-pollinator interactions between flowers and urban bees in the newer bee garden with a bipartite interaction network. Across 12 flower species, we observed two non-native pollinators, the honey bee (A. mellifera) and the alfalfa leafcutter (Megachile rotundata (Fabricius, 1793)), along with at least ten native bee species across three families (Apidae, Halictidae, Megachilidae). We found that, despite the garden being created for native bees, honey bees accounted for 84% of all pollination interactions. The most abundant native bees were sweat bees (Family: Halictidae). Generalist interactions dominated the network, as both honey and sweat bees foraged on most available flowers. Honey bees showed a significant positive correlation with floral abundance, visiting flowers with the highest number of inflorescences, whereas native bees did not show this preference. These results indicate that native bee garden stewardship could benefit from greater floral diversity, while avoiding the dominance of any single species with high floral abundance, thereby reducing the likelihood of direct competition with honey bees.