From bedrock to life activity and atmospheric deposition: Drivers of soil element coupling across horizons

Unraveling the intricate coupling of multiple elements and their underlying drivers in natural soils is crucial for comprehending ecosystem functions, yet this knowledge has remained elusive. Using a comprehensive dataset of 900 soil samples collected from 116 sites across 26 mountains, this study dissected the coupling relationship of 23 elements within three soil development horizons, spanning five climate zones in China. Our findings revealed a robust continental-scale coupling of soil elements, influenced by plants and environmental factors including spatial distance, climate, soil properties, and atmospheric nitrogen deposition, accounting for 36% of the observed variance in element coupling. Notably, our study unveiled the horizon-specific nature of element coupling mechanisms. In the parent horizon, rock type exerted the primary control on the dynamics of element coupling. However, as soil developed, life activities and atmospheric deposition of anthropogenic trace metals concurrently reshaped the element coupling patterns, particularly in the organic and surficial mineral horizons. Elements were divided into two distinct elemental groups, exhibiting opposite fitting trends with atomic mass and crustal abundance, and the effect of these properties on coupling diminished with soil depth. Heavy metals enriched by human activity deviated from property-based predictions with lower coupling. This study represents the first continental-scale quantification of multi-element coupling across soil horizons, underscoring the paramount importance of life activity and atmospheric deposition in modulating the initial lithological-mediated multi-element coupling. Our insights advance understanding of terrestrial ecosystem biogeochemistry and urge further research on the impacts of anthropogenic activities and environmental changes on these delicate elemental interactions.

Environmental controls on the conversion of nutrients to chlorophyll in lakes

Anthropogenic inputs of nitrogen and phosphorus to lakes have increased worldwide, causing phytoplankton chlorophyll concentrations to increase at many sites, with negative implications for biodiversity and human usage of lake resources. However, the conversion of nutrients to chlorophyll varies among lakes, hindering effective management actions to improve water quality. Here, using a rich global dataset, we explore how the relationship between chlorophyll-a (Chla) and nitrogen and phosphorus and inferred nutrient limitation is modified by climate, catchment, hydrology and lake characteristics. Phosphorus was the dominant control in oligotrophic/mesotrophic lakes, both nitrogen and phosphorus co-limitations were dominant in (hyper)eutrophic lakes, apart from hypereutrophic shallow lakes, where nitrogen was the main limiting factor. A generalized additive model of Chla vs nutrients identified a sigmoidal-type relationship with clear breakpoints between Chla and nutrients in all depth-dependent lake categories, except for nitrogen in shallow lakes. The model revealed that Secchi depth, as the predominant factor explaining the residuals, followed by the lake thermal region, elevation, and maximum depth. Lake shoreline slope, hydraulic retention time, mean depth, shoreline length, and watershed area were also statistically significant drivers for deep lakes. Surface area was only significant in shallow lakes, as it directly affects surface heating and surface contact with the wind, resulting in non-significant impact of thermal region in shallow lakes. These findings provide new insights into the response of global lake eutrophication and its main drivers, which could assist lake managers and policy-makers in mitigating widespread lake eutrophication.

Early life development and sex determination of brown trout affected by treated wastewater discharge

Artificial conditions limit the ability of laboratory studies to describe the complex effects of polluted environments on aquatic life. This study aimed to evaluate the impacts of treated wastewater discharge on the survival, growth, and sex ratio balance of the population of brown trout (Salmo trutta m. fario) in situ. Five floating incubators with 1000 eggs each were placed in the upstream reference and treated wastewater-affected sites in the Czech Republic for approximately three months. The hatched fish were grown in a natural environment for nearly one year. Water quality, including nutrients, temperature, pharmaceutical and personal care products, biological effects by bioassays and fish mortality, metabolic rate, and growth, were measured regularly. Up to 72 pharmaceutical and personal care products (7400-23000 ng/sampler) were detected in the passive samplers deployed downstream of the sewage treatment plant effluent. In vitro bioassays of the sampler extracts indicated elevated oestrogenic effects, transthyretin binding inhibition, and aryl hydrocarbon-mediated and androgenic potencies, showing endocrine-disrupting potential at the polluted site. The cumulated mortality of brown trout in the exposed group (9.67%) was significantly higher (p < 0.05) than in the control group (5.16%). In addition, the body size, growth, and metabolic rate of exposed fish were significantly lower (p < 0.05). The sex ratio of brown trout in the effluent-affected stretch was imbalanced, and sterile individuals were detected after several months of natural development in the stream. The observed effects of treated wastewater on the early developmental stages of aquatic wildlife could be connected to the development and readiness of adult individuals and, consequently, to the sustainability of freshwater ecosystems. Applying the hatching apparatus used in fishery practices, followed by comparing mortality, development, and sex with reference localities, seems to be a promising biomonitoring approach that can indicate hotspots for in-depth investigation and risk assessment.

Effect of farm size on vulnerability in beekeeping: Insights from mediterranean Spain

There is broad consensus on the socioeconomic importance of beekeeping and the essential services it provides through pollination. However, beekeeping is being impacted by global environmental changes, and more specific insights are needed. Beekeeping is not a homogeneous activity; it is practiced in various ways and contexts. This study examines how these changes affect beekeeping operations of different sizes in Mediterranean Spain and whether size influences adaptation. Structured interviews were conducted to assess the sector's vulnerability, with climate change identified as a key contributing factor. The findings reveal that the vulnerability of beekeeping is shaped not only by multiple transformations but also by the diverse adaptive capacities of beekeepers. Additionally, the size of beekeeping operations significantly influences this capacity, a factor that should be integrated into policymaking given the sector's highly polarized nature.

The ecological and evolutionary dynamics of inselbergs

Islands are fundamental model systems in ecology, biogeography, and evolutionary biology. However, terrestrial islands, unlike their aquatic counterparts, have received comparatively less attention. Among these land islands, inselbergs (i.e. isolated rock outcrops with diverse lithologies and a modest topographical prominence) stand out as iconic examples distributed worldwide across global biomes. Due to their durable lithology, inselbergs change slowly, persisting for tens of millions of years. In this review, we propose a biological definition for inselbergs that captures three fundamental characteristics of inselbergs from the perspective of biota. These are old age, isolation and the presence of unique microhabitats that are rare or absent in the surrounding matrix, fostering distinct communities often with unique and endemic biota. We synthesise the state of the art and formulate a set of testable hypotheses to deepen our understanding of the origins and maintenance of diversity on inselbergs, which are increasingly exposed to anthropogenic threats. By offering different habitats compared to the surrounding habitat matrix (e.g. moist microhabitats in dryland landscapes and xeric environments in humid tropical landscapes), inselbergs may allow specific lineages to thrive beyond their typical geographical limits. Particularly in drylands and degraded landscapes, inselbergs may not just provide different habitats but also act as ecological refuges or evolutionary refugia by providing a wider range of potential microhabitats than the surrounding matrix, enhancing resilience and promoting regional biodiversity. The central role of the matrix ensures that the ecological and evolutionary dynamics of inselbergs differ from those of true islands such as oceanic islands. Given that inselberg biota coexist within a terrestrial matrix, interactions between inselberg and matrix populations impact each other significantly. Over evolutionary timescales, matrix species may contract to inselberg refugia, preserving lineages while cycles of isolation and reconnection may drive speciation via a species pump. Although inselberg biodiversity has been studied predominantly from an island biogeography perspective, we argue that depending on the spatial scale, habitat specificity and mobility of the organisms considered, a range of different theories and paradigms can help explain the biogeography and local distribution patterns of different taxonomic and functional groups of inselberg species.

SYMRK significantly affected AMF symbiosis and plant growth in maize

Arbuscular mycorrhizal fungi (AMF) are important symbiotic microorganisms in the soil that form reciprocal relationships with most plants to enhance their ability to absorb nutrients from the soil. The establishment of symbiosis between plants and AMF involves complex molecular mechanisms, and the SYMRK (Symbiosis receptor-like kinase) plays a pivotal role in the establishment of symbiosis. Maize (Zea mays) is a globally significant crop and one of the hosts for AMF, but research on AMF symbiosis-related genes in maize is limited. In this study, we identified a symbiosis receptor-like kinase in maize, named ZmSYMRK, which corresponds to the ortholog gene OsSYMRK in rice. ZmSYMRK encodes a cell membrane-localized protein kinase that is crucial for AMF colonization. We demonstrated that ZmSYMRK deletion resulted in severe defects in maize symbiosis with AMF. The colonization rates of zmsymrk mutants were significantly reduced at three different time points, and the colonization defects did not recover with prolonged colonization time. Furthermore, the deletion of the ZmSYMRK gene severely affected plant growth under low phosphorus conditions, and the growth defects of the mutants were even more pronounced after symbiosis. We conclude that ZmSYMRK plays a crucial role in both plant growth and the establishment of symbiotic relationships with AMF.

Does death drive the scaling of life?

The magnitude of many kinds of biological structures and processes scale with organismal size, often in regular ways that can be described by power functions. Traditionally, many of these "biological scaling" relationships have been explained based on internal geometric, physical, and energetic constraints according to universal natural laws, such as the "surface law" and "3/4-power law". However, during the last three decades it has become increasingly apparent that biological scaling relationships vary greatly in response to various external (environmental) factors. In this review, I propose and provide several lines of evidence supporting a new ecological perspective that I call the "mortality theory of ecology" (MorTE). According to this viewpoint, mortality imposes time limits on the growth, development, and reproduction of organisms. Accordingly, small, vulnerable organisms subject to high mortality due to predation and other environmental hazards have evolved faster, shorter lives than larger, more protected organisms. A MorTE also includes various corollary, size-related internal and external causative factors (e.g. intraspecific resource competition, geometric surface area to volume effects on resource supply/transport and the protection of internal tissues from environmental hazards, internal homeostatic regulatory systems, incidence of pathogens and parasites, etc.) that impact the scaling of life. A mortality-centred approach successfully predicts the ranges of body-mass scaling slopes observed for many kinds of biological and ecological traits. Furthermore, I argue that mortality rate should be considered the ultimate (evolutionary) driver of the scaling of life, that is expressed in the context of other proximate (functional) drivers such as information-based biological regulation and spatial (geometric) and energetic (metabolic) constraints.

A novel method for frequency analysis of high water temperatures using temperature duration curves in a partially regulated watershed

Water temperature is the key variable for aquatic environmental assessments, and in the absence of long-term observational records, simulations provide essential data for further environmental analysis. In this study, we investigate the upper percentiles of a novel Temperature Duration Curve (TDC) as a proxy to characterize high water temperatures in a partially regulated watershed. The study area comprises the 47,200 km2 Nechako Watershed of British Columbia, Canada, where nine hydrometric stations measure streamflow and water temperature. Four sites represent regulated flows, while five sites are unregulated. Using daily streamflow and water temperature observations and ERA5-Land air temperature data, the Air2Stream model was calibrated for historical periods from 1950 to 2023. Simulations were also conducted using naturalized flows for the regulated Nechako River at Vanderhoof and Isle Pierre to reconstruct naturalized water temperatures. A frequency analysis was performed on observed, simulated, and naturalized water temperatures for different return periods and TDC percentiles. The analysis included exceedances of 0, 1, 5, and 10 % for high temperatures and the 50th percentile (median) for mean temperatures. Results showed robust model performance with RMSE <1.5 °C (NSE > 0.9 and KGE > 0.8) for all stations during calibration. The frequency curves showed reduced high temperatures for the Nechako River at Vanderhoof due to ecological flow releases, but increased mean temperatures for return periods >2 years. This novel approach suggests that thermal mandates should be related to Q5 and Q10, which had the best agreement between observations and simulations. The method is applicable globally across various basin sizes and hydrological regimes, making it a valuable tool for assessing water temperature dynamics in diverse environments.

Intraseasonal variations in the spatial behaviour of an Arctic predator

BACKGROUND

In highly constrained ecosystems such as in the Arctic, animals must constantly adjust their movements to cope with the highly versatile environmental conditions. However, to date most studies have focused on interseasonal differences in spatial behaviour, while intraseasonal dynamics are less described.

METHODS

To fill this knowledge gap, we studied the movement patterns of an Arctic predator, the arctic fox (Vulpes lagopus) at the intraseasonal scale. To unravel temporal patterns in space use and movement metrics, we used GPS data collected on 20 individual foxes between 2017 and 2023 in North-East Greenland.

RESULTS

We showed that weekly full and core home range sizes (estimated by means of Autocorrelated Kernel Density Estimates), and daily mean relative turning angles stayed constant throughout the summer. Conversely, daily distance travelled, mean daily speed and daily proportion of 'active' time showed intraseasonal variations. These fine-scale metrics had a hump-shaped distribution, peaking in mid-July, with males and non-breeding foxes travelling longer distances and being faster. Site-specific patterns were also identified, with foxes having smaller territories in the two most productive sites but moving shorter distances and at lower speeds at the poorest site.

CONCLUSION

Our study provides novel insights into how predators adjust their space use and behaviour to intraseasonal variations in environmental conditions. Specifically, we show that different movement metrics show different intraseasonal patterns. We also underline the importance of considering small spatiotemporal scales to fully understand predators' spatial behaviour.

Ornamental nurseries adjacent to hardwood-dominated woodlots pose more risk from exotic ambrosia beetles (Xylosandrus spp.) (Coleoptera: Curculionidae: Scolytinae) than pine-dominated woodlots

Exotic granulate ambrosia beetle, Xylosandrus crassiusculus (Motschulsky), black stem borer, Xylosandrus germanus (Blandford), and black twig borer, Xylosandrus compactus (Eichhoff) are serious pests of woody ornamental trees in nurseries. Woodlots often surround ornamental nurseries, where the ambrosia beetles fly into nurseries and attack young trees. The woodlots are either dominated by hardwood trees, such as Oaks (Oak spp.), maples (Acer spp.), or pine trees, mainly loblolly pine (Pinus taeda L.). It is unclear if the woodlot type would influence the abundance of ambrosia beetle pests flying outside the woodlot. Thus, this study aimed to determine whether the hardwood or pine-dominated stand affects the relative abundance of ambrosia beetle pests outside the woodlot. In 2023 and 2024, experiments were conducted by deploying 3 ethanol-lured plastic bottle traps in 4 hardwood and 4 pine-dominated woodlots in mid-Georgia (USA). The overall captures of X. crassiusculus and X. germanus were significantly greater in the hardwood than in the pine-dominated woodlots in both years. The numbers of X. crassiusculus and X. germanus collected in traps were not consistently significantly different between the hardwood and pine-dominated woodlots for most sampling dates. The captures of X. compactus were not influenced by woodlot type. This suggests that although ambrosia beetle pests were collected from both hardwood and pine-dominated woodlots in both years, the risk of infestation in nurseries is greater from the adjacent hardwood than pine-dominated woodlots.

Developmental Plasticity and the Evolutionary Rescue of a Colonizing Mite

Plasticity, especially in small newly founded populations, can expose genetic variation to selection during the evolutionary rescue of populations, allowing individuals to achieve a phenotype with which they can survive. However, developmental plasticity can also enable organisms to accommodate perturbations, generating new phenotypic variation. We explored whether, at the start of a colonization event, phenotype dynamics follow a "selective" process in which plasticity fuels evolutionary rescue or whether they are due to developmental plasticity in a "generative" process. We investigated this using the bulb mite Rhizoglyphus robini, which expresses a facultative, juvenile dispersal phenotype (deutonymph) under unfavorable conditions and shows alternative adult male phenotypes: competitive fighters or benign scramblers that are expressed to mitigate food stress and which have higher levels of genetic heterozygosity than fighters. Mimicking colonization dynamics, we founded small, medium and large populations from deutonymphs on low or high food to test if scramblers were expressed earliest postcolonization within (i) the smallest founder populations to alleviate inbreeding (selective hypothesis), or (ii) the largest founder populations as a direct consequence of food stress is highest due to higher food competition (generative hypothesis). In line with the generative hypothesis under both food environments, scramblers were expressed at the earliest in the largest founder populations, which also tended to show the lowest growth at the start of the experiment and had the lowest ultimate population size. Our findings highlight the necessity to seek explanations of how developmental pathways likely influence evolutionary rescue patterns, starting with how resource limitation (stress) shapes adaptive responses during colonization.

Long-term microbial functional responses in soil contaminated with biofuel/fossil fuel blends triggered by different bioremediation treatments

The use of biofuel blends with fossil fuels is widespread globally, raising concerns over novel contamination types in environments impacted by these mixtures. This study investigates the microbial functional in soils contaminated by biofuel and fossil fuel blends and subjected to various bioremediation treatments. Using metagenomic analysis, it was compared hydrocarbon degradation functional profiles across areas polluted with ethanol/gasoline and biodiesel/diesel blends. Results indicate that long-term natural attenuation areas exhibited distinct functional profiles compared to actively bioremediated areas. However, same hydrocarbon degradation genes were enriched across all areas, highlighting functional redundancy despite taxonomic variation in hydrocarbon-degrading microbes. Finally, several of the keystone species found were hydrocarbon degraders, such as members of the families Clostridiaceae and Comamonadaceae, representing potential targets for biostimulation in future remediation efforts. This long-term, field-scale study uniquely focuses on the functional profiles of microbial communities, offering new insights into the bioremediation of complex biofuel/fossil fuel contaminants in situ.

Metabolic ecology in aquatic ecosystems: Viewed from trophic compartments and communities in food webs

A different perspective in metabolic ecology is presented using food web data, based on trophic compartments and communities in aquatic ecosystems (coastal areas, shelves and estuaries in marine ecosystems, and lake ecosystems), including primary producers (phytoplankton and aquatic plants). The relationships among the metabolic traits (biomass, respiration and production) in aquatic communities are expressed through power laws, hence, the value of one of the three metabolic traits provides the values of the other two. Noteworthily, these metabolic traits (biomass, respiration, production) are related to those of primary producers according to various power laws. That is: the metabolic traits of communities can be estimated from those of primary producers alone. These power laws appear to be universal in marine ecosystems but vary among different lake ecosystems.

Optimizing the landscape in grain production and identifying trade-offs between ecological benefits based on production possibility frontiers: A case study of Beijing-Tianjin-Hebei region

There are severe conflicts between grain production and ecological benefits, and how to explore the critical configurations of agricultural landscapes and natural habitats to clarify sustainable scenarios remains unclear. Thus, this study explored a transferable approach to generating the production possibility frontiers of trade-offs between grain production and ecological benefits (biodiversity, carbon sink, and water consumption) under unconstrained, ecological constraint, and agricultural and ecological constraint scenarios, and identified the threshold and safety area for landscape optimization in the Beijing-Tianjin-Hebei (BTH) region of China. When reaching the Pareto optimality of trade-off frontiers, the grain yield and biodiversity increased by 10%-17%, the grain yield and carbon sink increased by 15%-48%, and the grain yield and water consumption improved by 4%-25%. The grain production and ecological benefits were outside the safety area in the BTH region, and the landscape optimization strategy was different for each trade-off. Both the food and biodiversity security can be further improved through increasing by 2.7% of cropland in the BTH region. The land use strategy of converting 6.8% of the cropland of the BTH region into forest land can promote carbon sink security. Although the land use strategy of converting 2.3% of the cropland of the BTH region into grassland can promote water security, more effort should be focused on technological innovation. This study highlights that landscape optimization will promote landscape multifunctionality and provides quantitative landscape optimization thresholds and safety boundaries for improving grain production and ecological benefits.

Faster than expected: release of nitrogen and phosphorus from decomposing woody litter

Deadwood represents globally important carbon (C), nitrogen (N), and phosphorus (P) pools. Current wood nutrient dynamics models are extensions of those developed for leaf litter decomposition. However, tissue structure and dominant decomposers differ between leaf and woody litter, and recent evidence suggests that decomposer stoichiometry, in combination with litter quality, may affect nutrient release. We quantified decomposition and release of C and nutrients from woody litter for two stem sizes of 22 tree species in a P-limited temperate forest near Sydney, Australia, and compared these to estimates from leaf litter literature. Following theory, N and P accumulated during early decomposition, but began to decline earlier than expected based on work in leaves. Woody litter converged on higher C : N (50) and N : P (80) ratios than in leaf litter studies. C : N at which N was released was higher in larger stems (c. 124) than in smaller stems (c. 82), both being higher than in leaf litter. Drawing from the literature, these differences in N and P dynamics may be due to the identity of wood decomposers. C : N of wood decomposers is higher than the mean C : N of leaf litter decomposers, and this difference in stoichiometry may have important flow-on effects for nutrient cycles in forests.

Nitrate leaching from soil under different forest tree species is related to the vertical distribution of Nitrobacter abundance

Forest tree species and their mineral N uptake strategies can influence the activity and abundance of nitrifying microorganisms in deeper soil layers and subsequent nitrate leaching. However, the role of nitrifier community from the topsoil or deeper soil layers for nitrate leaching below the rooting zone remains uncertain. We evaluated potential nitrification rates and the abundance of ammonia- and nitrite- oxidizers in soil profiles covered by different tree species having (i.e. spruce and Nordmann fir) or not (i.e. Douglas fir, Corsican pine and beech) the Biological Nitrification Inhibition, BNI, capacity. Concurrently, we calculated nitrate fluxes under each tree species by coupling nitrate concentrations in soil solutions with the hydrological model Watfor to simulate water percolation, and analyzed the relationships between nitrate fluxes and nitrifiers characteristics. We observed that nitrification rates under BNI species in the topsoil were lower than those under non-BNI species, and that these changes were associated to strong differences in the abundance of Nitrobacter (500-fold changes between tree species). Nitrification potentials drastically decreased with increasing soil depth and were strongly correlated with the abundance of Nitrobacter, not ammonia oxidizers. Furthermore, by computing weighted mean values of nitrifier activity and abundance, we showed that nitrate fluxes were explained by the abundance of Nitrobacter community across the 0-60 cm soil profile. In this context, the abundance of Nitrobacter community seems an interesting proxy for evaluating water quality at the plot scale, and a promising tool to understand and predict the risk of nitrate leaching from soils in temperate forest ecosystems.

Mechanistic insights into plant community responses to environmental variables: genome size, cellular nutrient investments, and metabolic tradeoffs

Affecting biodiversity, plants with larger genome sizes (GS) may be restricted in nutrient-poor conditions. This pattern has been attributed to their greater cellular nitrogen (N) and phosphorus (P) investments and hypothesized nutrient-investment tradeoffs between cell synthesis and physiological attributes associated with growth. However, the influence of GS on cell size and functioning may also contribute to GS-dependent growth responses to nutrients. To test whether and how GS is associated with cellular nutrient, stomata, and/or physiological attributes, we examined > 500 forbs and grasses from seven grassland sites conducting a long-term N and P fertilization experiment. Larger GS plants had increased cellular nutrient contents and larger, but fewer stomata than smaller GS plants. Larger GS grasses (but not forbs) also had lower photosynthetic rates and water-use efficiencies. However, nutrients had no direct effect on GS-dependent physiological attributes and GS-dependent physiological changes likely arise from how GS influences cells. At the driest sites, large GS grasses displayed high water-use efficiency mostly because transpiration was reduced relative to photosynthesis in these conditions. We suggest that climatic conditions and GS-associated cell traits that modify physiological responses, rather than resource-investment tradeoffs, largely explain GS-dependent growth responses to nutrients (especially for grasses).

Toward a More Dynamic Metabolic Theory of Ecology to Predict Climate Change Effects on Biological Systems

AbstractThe metabolic theory of ecology (MTE) aims to link biophysical constraints on individual metabolic rates to the emergence of patterns at the population and ecosystem scales. Because MTE links temperature's kinetic effects on individual metabolism to ecological processes at higher levels of organization, it holds great potential to mechanistically predict how complex ecological systems respond to warming and increased temperature fluctuations under climate change. To scale up from individuals to ecosystems, applications of classical MTE implicitly assume that focusing on steady-state dynamics and averaging temperature responses across individuals and populations adequately capture the dominant attributes of biological systems. However, in the context of climate change, frequent perturbations from steady state and rapid changes in thermal performance curves via plasticity and evolution are almost guaranteed. Here, we explain how some of the assumptions made when applying MTE's simplest canonical expression can lead to blind spots in understanding how temperature change affects biological systems and how this presents an opportunity for formal expansion of the theory. We review existing advances in this direction and provide a decision tree for identifying when dynamic modifications to classical MTE are needed for certain research questions. We conclude with empirical and theoretical challenges to be addressed in a more dynamic MTE for understanding biological change in an increasingly uncertain world.

Metapopulations, the Inflationary Effect, and Consequences for Public Health

AbstractThe metapopulation concept offers significant explanatory power in ecology and evolutionary biology. Metapopulations, a set of spatially distributed populations linked by dispersal, and their community and ecosystem level analogs, metacommunity and meta-ecosystem models, tend to be more stable regionally than locally. This fact is largely attributable to the interplay of spatiotemporal heterogeneity and dispersal (the inflationary effect). We highlight this underappreciated (but essential) role of spatiotemporal heterogeneity in metapopulation biology, present a novel expression for quantifying and defining the inflationary effect, and provide a mechanistic interpretation of how it arises and impacts population growth and abundance. We illustrate the effect with examples from infectious disease dynamics, including the hypothesis that policy decisions made during the COVID-19 pandemic generated spatiotemporal heterogeneity that enhanced the spread of disease. We finish by noting how spatiotemporal heterogeneity generates emergent population processes at large scales across many topics in the history of ecology, as diverse as natural enemy-victim dynamics, species coexistence, and conservation biology. Embracing the complexity of spatiotemporal heterogeneity is vital for future research on the persistence of populations.

Anatomical and Trait Analyses Reveal a Silicon-Carbon Trade-Off in the Epidermis of Sedges

In recent years, the detection of numerous negative correlations between silicon (Si) and carbon (C)-based compounds in plants has suggested trade-offs between different stress resistance and/or mechanical support strategies. However, nearly all studies have involved whole-leaf analysis, and it is unclear how the trade-off operates mechanistically, at the cellular level. Here we combined leaf trait measurements and microscopic analyses (electron microscopy with elemental X-ray mapping and X-ray microtomography) of 17 species from a high-Si family: Cyperaceae. Accumulation of Si was strongly negatively correlated with C-based compounds, particularly tannins. Our microscopical investigations showed that the accumulation of phenolics and deposition of silica were mutually exclusive in the outer epidermal cell walls. This trade-off was independent of that between the construction of tough, sclerenchyma-rich leaves and growth potential (the leaf economics spectrum). We also identified a strong negative correlation between Si and accumulation of epicuticular waxes. Previous whole leaf analyses were, in effect, hiding the locations of the trade-off between Si and C-based compounds in plants. The epidermal location of this trade-off and the specific involvement of tannins and waxes suggest the existence of different strategies to resist environmental stresses. Our study provides key insights into plant Si utilization and highlights the multidimensionality of plant stress resistance strategies.

Good moms: dependent young and their mothers cope better than others with longer dry season in plains zebras

In large herbivores, the timing of births often coincides with the seasonal peak of food resources availability, likely to improve juvenile survival and reduce reproduction costs. Some species, however, breed year-round, even in seasonal environments. Demographic processes, such as to what extent being born during the lean season reduces survival of juveniles and reproductive females, remain understudied in large mammals inhabiting tropical ecosystems. We investigated survival rates in plains zebras (Equus quagga) in Hwange National Park (Zimbabwe), a highly seasonal savanna ecosystem. We used capture-recapture models to analyse long-term demographic data (2008-2019). We investigated the effect of seasonality as a categorical (wet versus dry season) and continuous (duration of the dry season) variable on survival. We found little variability in early juvenile survival (φ = 0.458 ± 0.044 SE, < 6 m.o.), whereas late juvenile and yearling survivals were higher and decreased with increasing length of the dry season (from 0.850 ± 0.095 SE to 0.480 ± 0.120 SE). Female survival was high (> 0.703 ± 0.057 SE and up to 0.995 ± 0.006 SE) but decreased with exposure to the dry season in non-reproductive females. The probability of females becoming reproductive in the following year was not affected by the length of the dry season (0.423 and 0.420 for reproductive and non-reproductive females, respectively). Our results highlight the importance of individual quality in reproductive performance, as reproductive females seem to buffer the effect of environmental variability on their own survival and that of their foal.

Synergistic effects of elevated temperature with pesticides on reproduction, development and survival of dung beetles

In times of global change, high temperatures can increase the negative effects of pesticides and other stressors. The goal of this study was to evaluate, under controlled laboratory conditions, the effect of a moderate increase in temperature in combination with ivermectin (an antiparasitic medication used in cattle that is excreted in dung), an herbicide, and parasitic pressure, on the reproductive success, development time and adult survival of dung beetles Euoniticellus intermedius. Whereas high temperature increased the number and proportion of emerged offspring, it had synergistic negative effects in combination with the ivermectin, herbicide and parasite treatments. Moreover, high temperature in combination with ivermectin and with parasitism caused a synergistic increase of adult offspring mortality and, in combination with the herbicide, it synergistically accelerated development. These results indicate that high temperatures can enhance the negative effects of other stressors and act synergistically with them, harming dung beetles, a group with high ecological and economic value in natural and productive ecosystems. Although adult sex ratio was not affected by experimental treatments, contrasting responses were found between males and females, supporting the idea that both sexes use different physiological mechanisms to cope with the same environmental challenges. The effects that combined stressors have on insects deepen our understanding of why we are losing beneficial species and their functions in times of drastic environmental changes.

How do trees fail in intraspecific competition? A test for the roles of non-structural carbohydrates and stoichiometries in Pinus massoniana

Competition is ubiquitous and an important driver of tree mortality. Non-structural carbohydrates (NSCs, including soluble sugars and starch) and C-N-P stoichiometries are affected by the competitive status of trees and, in turn, physiologically determine tree growth and survival in competition. However, the physiological mechanisms behind tree mortality caused by intraspecific competition remain unclear. Here, we ask how the performance (growth vigour) of trees in intraspecific competition relates to NSC and C-N-P stoichiometry traits. Through the field surveys at neighbourhood levels, we demonstrated that competition is responsible for tree mortality in an even-aged Pinus massoniana forest. The whole NSCs and C-N-P stoichiometries of trees in different growth vigour classes (i.e., flourishing, moderate, and dying) were then analysed to elucidate how trees fail in competition. We found that (1) the concentrations of NSCs and their components in stems, coarse roots and fine roots were constant across tree growth vigour classes, but were significantly lower in the leaves, twigs and branches of moderate and dying trees than those of flourishing trees, and (2) the C, N and P concentration and their respective ratios were constant in all the tissues across tree growth vigour classes, but the nitrogen stoichiometric homeostasis index (HN) of flourishing trees was significantly higher than that of moderate and dying trees. The results demonstrated that both carbohydrate deficiency and low stoichiometric homeostasis are potential physiological drivers underlying tree mortality caused by intraspecific competition. This study also emphasizes the importance of considering stoichiometric homeostasis in research on tree competition and forest dynamics.

Intraspecific body size variation across distributional moments reveals trait filtering processes

Natural populations are composed of individuals that vary in their morphological traits, timing and interactions. The distribution of a trait can be described by several dimensions, or mathematical moments-mean, variance, skew and kurtosis. Shifts in the distribution of a trait across these moments in response to environmental variation can help to reveal which trait values are gained or lost, and consequently how trait filtering processes are altering populations. To examine the role and drivers of intraspecific variation within a trait filtering framework, we investigate variation in body size among five wild bumblebee species in the Colorado Rocky Mountains. First, we examine the relationships between environmental factors (climate and floral food resources) and body size distributions across bumblebee social castes to identify demographic responses to environmental variation. Next, we examine changes in the moments of trait distributions to reveal potential mechanisms behind intraspecific shifts in body size. Finally, we examine how intraspecific body size variation is related to diet breadth and phenology. We found that climate conditions have a strong effect on observed body size variation across all distributional moments, but the filtering mechanism varies by social caste. For example, with earlier spring snowmelt queens declined in mean size and became negatively skewed and more kurtotic. This suggests a skewed filter admitting a greater frequency of small individuals. With greater availability of floral food resources, queens increased in mean size, but workers and males decreased in size. Observed shifts in body size variation also correspond with variation in diet breadth and phenology. Populations with larger average body size were associated with more generalized foraging in workers of short-tongued species and increased specialization in longer-tongued workers. Altered phenological timing was associated with species- and caste-specific shifts in skew. Across an assemblage of wild bumblebees, we find complex patterns of trait variation that may not have been captured if we had simply considered mean and variance. The four-moment approach we employ here provides holistic insight into intraspecific trait variation, which may otherwise be overlooked and reveals potential underlying filtering processes driving such variation within populations.

Differences in phenological term changes in field crops and wild plants - do they have the same response to climate change in Central Europe?

Phenological shifts in wild-growing plants and wild animal phenophases are well documented at many European sites. Less is known about phenological shifts in agricultural plants and how wild ecosystem phenology interacts with crop phenology. Here, we present long-term phenological observations (1961-2021) from the Czech Republic for wild plants and agricultural crops and how the timing of phenophases differs from each other. The phenology of wild-growing plants was observed at various experimental sites with no agriculture or forestry management within the Czech Hydrometeorological Institute observations. The phenological data of the crops were collected from small experimental plots at the Central Institute for Supervising and Testing in Agriculture. The data clearly show a tendency to shift to earlier times during the observation period. The data also show some asynchrony in phenological shifts. Compared with wild plants, agricultural crops showed more expressive shifts to the start of the season. Phenological trends for crop plants (Triticum aestivum) showed accelerated shifts of 4.1 and 5.1 days per decade at low and middle altitudes, respectively; on the other hand, the average phenological shift for wild plants showed smaller shifts of 2.7 and 2.9 days per decade at low and middle altitudes, respectively. The phenophase ´heading´ of T. aestivum showed the highest correlation with maximum temperatures (r = 0.9), followed by wild species (with r = 0.7-0.8) and two remaining phenophases of T. aestivum jointing and ripening (with r = 0.7 and 0.6). To better understand the impacts of climate on phenological changes, it is optimal to evaluate natural and unaffected plant responses in wild species since the phenology of field crops is most probably influenced not only by climate but also by agricultural management.

Frankenstein matrices: Among-population life history variation affects the reliability and predictions of demographic models

Population matrix models are routinely used to study the demography of wild populations and to guide management choices. When vital rates are unknown for a specific population or life history stage, researchers often replace them with estimates from other populations of the same species. Such 'hybrid' matrices might ignore among-population life history variation and lead to incorrect inferences. In this study, we examined the real-world effect of using hybrid matrices on demographic inference and management decisions, using a large dataset on yellow-bellied toad (Bombina variegata) populations, an amphibian species whose life history depends on human land use. We estimated stage-specific survival and recruitment for 18 populations across different habitat types. We then assessed how estimated population growth rates and elasticities changed when population-specific vital rates were replaced by estimates from other populations, chosen randomly or based on habitat, demographic or geographic proximity. The use of hybrid matrices mixing demographic estimates from different populations and habitats biased predictions. The mean bias was relatively minor even when sampling randomly across all populations, because our large dataset represented the whole range of life histories and errors cancelled out on average. However, borrowing estimates from geographically close or demographically similar populations substantially reduced the risk of extreme errors. Borrowing from populations from similar habitat types could also reduce bias, but results varied depending on the exact habitat types concerned. Our study illustrates how habitat-specific among-population variation in life history affects the reliability of population matrices commonly used in evolutionary demography, ecology and conservation. When the use of hybrid population matrices cannot be avoided, their creation can be informed by additional information about ecological or demographic patterns, helping reduce bias. When such information is not available, we recommend that studies should consider the whole space of parameter estimates (the complete range of estimates available), thus transparently describing the true uncertainty surrounding demographic estimates.

Past and present bacterial communities in deglaciating northern latitude catchments reveal varied soil carbon sequestration potential

Glacier retreat in northern latitudes exposes new landscapes that may develop soils and ecosystems, which in turn may sequester carbon and serve as a negative climate change feedback. Proglacial soil development and landscape evolution were investigated using transects from three high-latitude glacial systems (Tarfala, Sweden; Vatnajökull, Iceland; Zackenberg, Greenland). Soil samples were analysed for organic carbon (OC) concentration, bacteriohopanepolyol biomarkers (BHPs, membrane lipids that trace major microbial groups), and 16S rRNA gene sequencing. Soil and sediment samples from Sweden showed lower OC concentrations (0.27 ± 0.26 wt%) than deposits from Iceland (1.59 ± 2.12 wt%) and Greenland (1.62 ± 1.54 wt%). Highest OC concentrations were from moraines exposed for several millennia, while recently deglaciated areas in Sweden and Iceland had the lowest OC values. Higher fractional abundance of soil-specific BHPs down-valley (up to 30 % in Greenland), and matching increases in the R'soil index (up to 0.37 in Greenland), suggest soils are gradually developing in recently deglaciated areas, with a stable soil microbial community observed in some soils from Iceland and Greenland. Microbial communities stabilized quickly, adapting to the new environment. Acidobacteria, Actinobacteria, Chloroflexi, Proteobacteria, Planctomycetes, and Verrucomicrobia were the most relatively abundant phyla identified in deglaciated areas, while candidate phylum Dormibacteraeota had high concentrations in samples from Sweden. Linking organic biomarkers with bacterial communities suggests that soil-marker BHPs were produced by Rhodospirillaceae and may have been produced by Bradyrhizobiaceae and Hyphomicrobiaceae. However, despite some similarities in microbial communities, differences in soil development suggest that the evolution of deglaciating landscapes and their impact on the global carbon cycle may vary substantially.

Salt marsh macrofauna: An overview of functions and services

Salt marshes are globally important blue carbon ecosystems, providing essential services such as coastal protection, carbon sequestration, nutrient cycling, and biodiversity support. Among their key inhabitants, macrofauna play critical roles in sustaining ecosystem health and resilience through processes like bioturbation, nutrient cycling, organic matter turnover, and trophic interactions, which in turn support ecosystem services such as fisheries and coastal community livelihoods. Despite their contributions, no comprehensive review has yet focused exclusively on the diverse roles and services of salt marsh macrofauna. This review aims to address this gap by synthesizing current research, supported by a bibliometric analysis revealing significant growth in studies since the year 2000, especially those addressing ecosystem services and climate resilience. We provide an in-depth assessment of macrofaunal functions in bioturbation, nutrient cycling, organic matter dynamics, greenhouse gas regulation, primary and secondary production, and food web interactions. Additionally, we examine the ecosystem services provided, such as provisioning, regulating, and cultural services, and explore the impact of environmental stressors on macrofaunal communities. Finally, this review identifies significant knowledge gaps, offering strategic insights for future research and serving as a vital reference for advancing coastal management and salt marsh conservation strategies.

Plasticity in mosquito size and thermal tolerance across a latitudinal climate gradient

Variation in heat tolerance among populations can determine whether a species is able to cope with ongoing climate change. Such variation may be especially important for ectotherms whose body temperatures, and consequently, physiological processes, are regulated by external conditions. Additionally, differences in body size are often associated with latitudinal clines, thought to be driven by climate gradients. While studies have begun to explore variation in body size and heat tolerance within species, our understanding of these patterns across large spatial scales, particularly regarding the roles of plasticity and genetic differences, remains incomplete. Here, we examine body size, as measured by wing length, and thermal tolerance, as measured by the time to immobilisation at high temperatures ("thermal knockdown"), in populations of the mosquito Aedes sierrensis collected from across a large latitudinal climate gradient spanning 1300 km (34-44° N). We find that mosquitoes collected from lower latitudes and warmer climates were more tolerant of high temperatures than those collected from higher latitudes and colder climates. Moreover, body size increased with latitude and decreased with temperature, a pattern consistent with James' rule, which appears to be a result of plasticity rather than genetic variation. Our results suggest that warmer environments produce smaller and more thermally tolerant populations.

Indoor bioaerosols and asthma: Overview, implications, and mitigation strategies

Aerosolized particles with a biological origin are called bioaerosols. Bioaerosols from plants, animals, fungi, bacteria, and viruses are an important class of environmental exposures that are clinically relevant to asthma. However, there are important differences in the pathways by which various bioaerosols affect asthma. Additionally, differences in individual susceptibility to different bioaerosols affect exposure reduction and mitigation strategies. Strategies to reduce exposures to potential triggers of asthma are routinely considered as part of standard clinical care and asthma management guidelines. Ventilation standards in buildings may reduce bioaerosol exposure for everyone, but they are not necessarily designed specifically to protect patients with asthma. Direct measurement of a bioaerosol is not generally necessary for practical applications where the relevant source of the bioaerosol has been identified. Different types of bioaerosols can be controlled with similar strategies that prioritize source control (eg, reducing resuspension, integrated pest management, controlling moisture), and these can be supplemented by enhancing air filtration. The goal of this review is to summarize the latest information on bioaerosols, including allergens, fungi, bacteria, and viruses, that have been associated with adverse asthma outcomes and to discuss mitigation options.

The complex structure of aquatic food webs emerges from a few assembly rules

Food-web theory assumes that larger-bodied predators generally select larger prey. This allometric rule fails to explain a considerable fraction of trophic links in aquatic food webs. Here we show that food-web constraints result in guilds of predators that vary in size but have specialized on prey of the same size, and that the distribution of such specialist guilds explains about one-half of the food-web structure. We classified 517 pelagic species into five predator functional groups. Most of these follow three prey selection strategies: a guild following the allometric rule whereby larger predators eat larger prey and two guilds of specialists that prefer either smaller or larger prey than predicted by the allometric rule. Such coexistence of non-specialist and specialist guilds independent from taxa or body size points towards structural principles behind ecological complexity. We show that the pattern describes >90% of observed linkages in 218 food webs in 18 aquatic ecosystems worldwide. The pattern can be linked to eco-evolutionary constraints to prey exploitation and provides a blueprint for more effective food-web models.

Effects of soybean fields on the health of Apis mellifera (Hymenoptera: Apidae) in the Chaco ecoregion

Honey bees (Apis mellifera) are important pollinators for natural and cultivated species. Due to their high sensitivity to stressors, they are also valuable indicators of environmental changes and agricultural management practices. In this study, we compared the performance and incidence of pesticides over sentinel hives within forest remnants with those within linear forest fragments (LFF) surrounded by soybean fields under conventional management. Sentinel hives in LFF showed some signs of deterioration, such as colony collapse, low numbers of brood frames, and pesticide occurrences, but honey production and the number of adult bees were similar to hives in the forest. Soybean pollen was scarce in honey and absent in bee bread, suggesting that bees may be relying more on wild plant species. We detected 5 pesticides (azoxystrobin, carbendazim, chlorpyrifos, imidacloprid, and coumaphos) in hives both at forests and LFF in pollen, bee bodies, and wax; pesticides in honey were detected in old sentinel hives (2 yr of exposition to agricultural conventional management). Only 2 of the 5 pesticides were applied in one of the farms under study, highlighting the importance of considering landscape-scale agricultural management. Our results indicate that conventional agriculture of soybean/maize primarily affected the performance of beehives, and pesticides were detected in honey only after long exposure to hives. Beekeeping in soybean fields in the Chaco could be feasible if cautions were followed, such as the conservation of forest fragments and key plant species, appropriate pesticide schedules, coordinated applications among farms, and linear forest remnants improvements.

Integrating data to assess occupancy patterns of an endangered bumble bee

There is growing interest in integrating community science data with structured monitoring data to estimate changes in distribution patterns of imperiled species, including pollinators. However, significant challenges remain in determining how unstructured community science data should be incorporated into formal analyses of species distributions. We developed a dynamic framework for combining community science and structured monitoring data of bumble bees to estimate changes in occupancy of rusty-patched bumble bees (Bombus affinis), a federally endangered species in the United States. We applied traditional metapopulation theory and accounted for imperfect detection to estimate site-specific extirpation risk and colonization rates across the known distribution of B. affinis in the Upper Midwest (USA). Despite a 144% increase in presence-only detections from 2017 to 2022, occupancy probabilities and the estimated number of occupied sites remained static or declined slightly across a 4-state region during this period. Our results provide preliminary evidence that the probability of local extirpation risk of B. affinis increased in response to drought, but that effect was tempered with a high number of neighboring patches occupied by B. affinis (i.e., rescue effect). Our framework can be used by managers to track population recovery goals for B. affinis and other bumble bees of conservation concern. In addition, our study highlights the importance of accounting for imperfect detection and addressing spatial sampling biases in bumble bee monitoring efforts, particularly those for which a portion of the monitoring data are generated from community science projects.

How will the cumulative effects of fishing and climate change affect the health and resilience of the Celtic Sea ecosystem?

Ecosystems are subject to increasing anthropogenic pressures worldwide. Assessing cumulative effects of multiple pressures and their impacts on recovery processes is a daunting scientific and technical challenge due to systems' complexity. However, this is of paramount importance in the context of ecosystem-based management of natural systems. Our study provides major insights into the assessment of cumulative effects on Northeast Atlantic ecosystems. Using an Ecopath with Ecosim (EwE) tropho-dynamic model for the Celtic Sea ecosystem including 53 functional groups, we (1) assess individual and cumulative effects of fishing and climate change and (2) explore the impact of fishing intensity and climate change on ecosystem resilience. Various levels of increasing fishing intensities are simulated over the whole 21st century, by forcing the EwE model with time series of sea temperature, primary production and secondary producer's biomass from the regional POLCOMS-ERSEM climate model, under both RCP4.5 and RCP8.5 scenarios. Cumulative impacts on the ecosystem's health and its capacity to recover after the cessation of fishing activities were assessed through a set of 45 indicators (biomass-based, diversity, trait-based and habitat-based indicators), using a theoretical non-fishing and climate-constant scenario as a reference. Our results reveal climate change impacts on Boreal, pelagic species and on ecosystem stability. Fishing preferentially removes apex predators and is predicted to increase the likelihood of a regime shift by decreasing ecosystems' capacity to recover. Predicted cumulative effects are mainly additive and antagonistic but synergies are observed for high fishing effort levels, and finally climate change had minor impacts on ecosystem recovery to fishing. Fishing is shown to be the main driver of cumulative impacts and of ecosystem resilience over the next decades. Our results suggest that slight reduction in fishing effort is enough to compensate the impact of climate change. Future research should then be directed towards exploring and evaluating ecosystem-based climate-adaptive fisheries management strategies.

Forest Wildfire Increases the Seasonal Allocation of Soil Labile Carbon Fractions Due to the Transition from Microbial K- to r-Strategists

Promoting the formation and accumulation of soil carbon (C) is one of the natural solutions to address climate change, but frequent wildfires increase its uncertainty and challenge. This two-year study deciphered the driving pathways of seasonal and vertical patterns in a soil C pool following a wildfire from a microbial perspective. Results showed that total organic C concentration and stock postfire decreased by 29.9 and 17.5% on average compared with the unburned control, respectively, whereas the allocations of labile C increased by 25.1-45.7%. Fire-induced alterations in labile C fractions were complicated due to their significant seasonality and respective sensitivities. Nonetheless, we emphasized that microbial life-history traits were the decisive mediators of variations and that significant positive linkages existed between labile C and microbial r-selected communities. Fire stimulated lower bacterial and fungal copiotroph/oligotroph ratios and higher ribosomal ribonucleic acid operon copy number, shifting microbes from K- to r-strategists. From integrated soil C pool management indices, fire can be concluded to reduce C stability and accelerate C cycling, but whether the recaptured prevalence of K-strategist over time will modify C processes remains unknown. This study provided a stepping stone for future efforts in accurate C predictions and reasonable C management.

Integrating "nature" in the water-energy-food Nexus: Current perspectives and future directions

Integrated approaches for managing natural resources are said to meet increasing demand for water, energy, and food, while maintaining the integrity of ecosystems, and ensuring equitable access to resources. The Water-Energy-Food (WEF) Nexus has been proposed as a cross-sectoral approach to manage trade-offs and exploit synergies that arise among these sectors. Although not initially included as a component of the Nexus, the role of nature in sustaining the water, energy, and food sectors and in regulating their interrelationships is increasingly recognised by Nexus researchers and practitioners. To converge existing approaches that integrate nature into the WEF Nexus and suggest a common framework, we - an interdisciplinary group of natural resources management researchers and systems thinkers from the European research network NEXUSNET COST Action - followed a collaborative process of knowledge creation combining literature review, elicitation of expert opinion and collaborative writing. Our results reveal a multiplicity of concepts utilised in the literature to represent, partially or fully, "nature" in the Nexus, such as "environment", "ecosystems", "ecosystem services", "social-ecological systems", and "biodiversity". Disparity was also found in the role attributed to nature, represented by three key paradigms: (1) ecosystems as the fourth component of an expanded Nexus, i.e., the WEF-Ecosystems (WEFE) Nexus; (2) ecosystems as a foundational layer to the Nexus; and (3) the WEF Nexus as a central component of social-ecological systems (SES). By creating a hybrid approach that brings together the benefits of the respective paradigms, we present a forward-looking WEFE Nexus conceptualisation. This paradigm expands the mutual interlinkages among water, energy and food to the entirety of SES, thus acknowledging the social-ecological processes that are affected by and affect the WEF Nexus. The results of this collaborative research effort intend to provide researchers and stakeholders with means to better understand and ultimately manage Nexus issues towards a transformative change.

Morphological and pomological variations of Pistacia atlantica Desf. subsp. cabulica and subsp. mutica in Sistan-va-Baluchestan province, Iran

BACKGROUND

The genus Pistacia, belonging to the family Anacardiaceae, includes various species that hold ecological, nutritional, and medicinal significance. There is limited information on the morphological and pomological diversity of Pistacia atlantica Desf. subsp. cabulica and subsp. mutica. This study aims to examine this diversity and contribute to the improvement of sustainable use and agricultural practices.

RESULTS

Morphological and pomological variation of 44 female accessions of P. atlantica (20 of subsp. cabulica and 24 of subsp. mutica) grown naturally in Mount Taftan, Sistan-va-Baluchestan, Iran, was assessed. One-way ANOVA (p < 0.05) showed significant differences among the examined genotypes. The coefficient of variation (CV) ranged from 7.60% (kernel thickness) to 167.04% (kernel crispness), with 34 out of 48 traits (70.83%) showing CVs greater than 20%, indicating high variability. The range of leaf-related characters was as follows: leaf length: 87.52-157.80 mm, leaf width: 55.28-121.97 mm, leaflets per leaf: 5-7, petiole length: 25.87-66.91 mm, and petiole diameter: 1.15-2.2 mm. The range of fruit-related characters was as follows: bunchlets per bunch: 10-17, fruit pedicel length: 1.37-7.12 mm, fruit pedicel width: 0.9-1.23 mm, nut length: 5.49-8.23 mm, nut width: 6.19-8.42 mm, nut thickness: 4.39-6.42 mm, and 100-nut weight: 12.36-25.91 g. These variations indicate adaptability and agricultural potential. Most accessions showed moderate growth, intermediate vigor, and branching, optimizing photosynthesis. Leaf and petiole traits vary, reflecting adaptations to environmental conditions. Ripening times span from late September to mid-October, with yield potential mostly intermediate. According to correlation matrix analysis, high positive correlations were found between 100-nut weight and kernel thickness (r = 0.708**), nut length (r = 0.764**), and nut thickness (r = 0.603**), and these correlations are also supported by multiple regression analysis (β = 0.47, β = 0.69, β = 0.31, P < 0.00, respectively). According to principal components analysis, the first three principal components (PC1 = 13.39%, PC2 = 9.30%, and PC3 = 9.25%) represented 31.94% of the total variation. The datasets were evaluated together, and the first 14 accessions were detected, including four accessions of subsp. mutica (No. 23, 5, 11, and 16) and 11 accessions of subsp. cabulica (No. 5, 15, 18, 10, 20, 12, 1, 7, 17, and 13), respectively. The accessions 1 and 7 of subsp. cabulica, though among the first 14, fall outside the 95% confidence ellipse in the scatter plot, indicating that they differ significantly from the others in terms of their traits. This suggests they may possess unique characteristics.

CONCLUSIONS

This study highlights the significant morphological and pomological diversity between the P. atlantica subsp. cabulica and subsp. mutica, providing valuable insights for breeding and conservation. The key trait relationships identified through statistical analysis may guide trait selection for better yield and adaptability.

Primary producers in freshwater ecosystem respond differently to multiple environmental stressors: A mesocosm study

Primary producers play key roles in maintaining a clear-water phase and promoting biodiversity in shallow aquatic ecosystems. Environmental stressors from anthropogenic activities, such as eutrophication and pesticide pollution, individually and in combination, can drive these ecosystems into a turbid state, potentially leading to a regime shift. In this 111-day study, we used 40 mesocosms (200 L) to simulate shallow lakes dominated by two typical macrophytes: the bottom-dwelling densely Vallisneria denseserrulata and the floating Spirodela polyrrhiza, along with associated food web components. We tested the interactive effects of nutrient loading, glyphosate-based herbicides, and imidacloprid insecticides on the growth of aquatic plants, phytoplankton, and periphyton. Our results indicate that meso-eutrophication, glyphosate and imidacloprid directly or indirectly affected aquatic primary producers, with the type of interaction (synergistic, antagonistic and additive) related to the form of the primary producer. Meso-eutrophication alone increased the biomass of all organisms except submerged plants, glyphosate alone decreased the biomass of all organisms except phytoplankton, with particularly strong effects on aquatic plants, and imidacloprid alone affected only aquatic animals. While combinations of multiple stressors generally increased algal biomass and decreased macrophyte biomass, submerged macrophytes consistently helped control algal blooms. These results demonstrate the risk of algal blooms in shallow lakes within agricultural landscapes and emphasize the crucial role of macrophytes in preventing algal blooms and maintaining healthy lake ecosystems.

Response patterns of benthic functioning in tropical estuaries under varying scales of anthropogenic perturbations

Multifarious human pressures can adversely impact estuaries' benthic functioning, yet this is less understood in tropical regions. This study examined the macrobenthic functional patterns of three differentially impacted tropical estuaries to elucidate the response of traits to stress, link taxonomical and functional structures and metrics and identify influential environmental factors of benthic functioning. Taxonomic and functional indices were positively correlated, suggesting that estuaries were vulnerable to functional shifts following species extinction due to environmental changes. Traits like 'feeding behavior', 'position in sediment', 'lifespan' and 'ecological sensitivity' were found effective markers of stressed zones, where resistant modalities predominated in response to disturbances. Rao's Quadratic entropy (RaoQ) successfully distinguished estuarine zones based on pollution levels, while other functional metrics (richness, evenness, divergence) exhibited anomalous trends. The complementary RLQ and Fourth-corner analyses could effectively discriminate disturbed zones in Ulhas, the estuary with a strong pollution gradient. Specific bivariate functional trait-environmental factor relationships were stronger in more impacted estuaries, while they were less so in the less impacted estuary. Environmental filtering facilitated trait clustering in polluted zones and trait divergence in less polluted estuaries. Salinity, pollutants and granulometry were the major influential factors of functional metrics. The Pressure Index was negatively correlated with RaoQ index only in Ulhas indicating that the discriminatory abilities of functional traits and indices were most effective in highly polluted estuaries. These results provide valuable insights to support sustainable management practices for these critical coastal ecosystems.

Interconnecting fragmented forests: Small and mobile birds are cornerstones in the plant-frugivore meta-network

Habitat fragmentation is causing the collapse of seed dispersal interactions and ecosystem functioning. When management and conservation strategies aim to sustain ecosystem functioning of fragmented forests, species' traits and functional performance are critical in guiding decisions. However, to date, we lack a quantitative understanding of the role of frugivores' body size and dispersal ability in ecosystem sustainability among fragmented forests. Focusing on avian frugivory and seed dispersal in a multi-island setting, we address the data gap by recording more than 20,000 frugivory events in an artificial insular fragmented landscape constructed in 1959 and nearby unfragmented forests on the mainland. We show that large-bodied and dispersal-limited frugivorous birds are largely confined to large islands and the unfragmented mainland, whereas on small islands, small-bodied and highly mobile birds predominantly engage in frugivory interactions. The plant-frugivore meta-network exhibits a distinct compartmentalization, driven by island area and bird mobility. Birds with smaller size and greater mobility have higher topological importance, and the presence of small-bodied birds significantly enhances meta-network robustness. These results suggest that among insular fragmented forests where frugivory interactions are degraded, small-bodied and highly mobile birds disproportionately contribute to meta-community cohesion and ecosystem functioning because of the lack of large-bodied and dispersal-limited birds. We thus advocate for the restoration of landscapes to facilitate seed dispersal and functional connectivity, ensuring the presence of large patches along with small patches as stepping-stones. Meanwhile, we recommend prioritizing conservation on small-bodied and highly mobile birds in fragmented landscapes, a subset of underappreciated species that yet play crucial roles in ecosystem functioning.

Allometric scaling and carbon sequestration in agroforestry species of the Western Himalayas: a model-based approach

Agroforestry offers a huge potential for carbon sequestration, contributing to climate change mitigation and carbon trading. This study focuses on Bauhinia variegata and Celtis australis, two important agroforestry tree species in the Western Himalayas aiming to develop allometric models and biomass prediction ratios using empirical data collected through selective sampling and minimally destructive methods. Biomass components were categorized and weighed, and allometric equations were developed using diameter at breast height and height as independent variables. Model stability was validated using cross-validation techniques, and their predictive accuracy was assessed. Models, particularly based on diameter, has significant predictive ability for predicting the biomass components for both the species. B. variegata demonstrated a higher capacity for CO2 absorption and carbon credit generation. The biomass expansion factor and root-to-shoot ratio for C. australis and B. variegata was estimated to be 1.39 and 1.40; and 0.24 and 0.17, respectively. The annual biomass of B. variegata and C. australis was 5.97 and 4.67 Mg ha-1 yr-1, respectively. The total carbon stock for both species varied from 23.80 to 30.47 Mg C ha-1. In B. variegata and C. australis, carbon sequestration was 105.93 and 82.11 Mg ha-1, respectively, and net oxygen release ranged from 59.72 to 77.04 Mg ha-1. The carbon sequestration by B. variegata translates into generating US$ 2119 in total carbon credits, with an annual credit of US$ 193, while C. australis yields US$ 1642 in total credits and US$ 149 annually. These findings highlight the utility of B. variegata and C. australis for carbon sequestration and provide valuable allometric equations for carbon credit estimation. The study emphasizes the importance of agroforestry in meeting India's Nationally Determined Contributions and addressing climate policy goals.

The micro-niche explains allotopy and syntopy in South American Liolaemus (Iguania: Liolaemidae) lizards

Species distribution models have been established as essential tools for projecting the effects of changing environmental conditions on species distribution across space and time. The microclimatic niche denotes the environmental conditions within a habitat at a small scale or localized area. These conditions have a direct influence on several ecological traits and on species distribution as these conditions determine which organisms can survive and/or reproduce. This study examines the microclimate data from four sites located in Northwestern Salta Province, Argentina. Four South American Liolaemus lizard species were found to inhabit these four sites in allotopy or syntopy, with Liolaemus irregularis inhabiting all four sites. Liolaemus irregularis is the sole Liolaemus species inhabiting Site 1; L. irregularis inhabits Site 2 in syntopy with L. multicolor; L. irregularis inhabits Site 3 in syntopy with L. yanalcu; and L. irregularis inhabits Site 4 in syntopy with L. albiceps. To characterize the four sites, a microclimate model was generated for an interval from 10 AM to 6 PM every day, for 10 years. The sites exhibited some differences in the combination of climatic and soil characteristics. Site 1 was characterized by low relative humidity, high temperature, high wind speed, and Cambisol soil type. Site 2 had high relative humidity, low temperature, moderate wind speed, and Andosol soil type. Site 3 had high relative humidity, high temperature, low wind speed, and Cambisol soil type. Site 4 had high relative humidity, low temperature, moderate wind speed, and Regosol soil type. Temperature, humidity, wind speed, soil type, and species diet influenced the presence of lizard species at each site. It is evident that microenvironmental conditions profoundly influence lizard distribution and biological interactions.

Thermal physiology of dung beetles exposed to ivermectin, a veterinary drug

Global changes, including increasing temperatures and pesticide contamination threaten insect survival and reproduction by altering metabolism and stress responses. Of particular importance are insects that provide ecosystem services and are threatened by multiple stressors, such as dung beetles, which bury dung in forests and cattle pastures. This study investigated how elevated temperature and ivermectin, a common antiparasitic medication used in cattle that is excreted in dung, affect the thermal physiology of Euoniticellus intermedius dung beetles under controlled laboratory conditions. Our study evaluated, under laboratory conditions, the effect of the combination of high temperature and ivermectin, on heat tolerance, metabolic rate, and survival of female dung beetles E. intermedius. We found that ivermectin reduced survival at 29 °C but not at 33 °C, potentially due to heat-induced hormetic effects, which activate defense systems, protecting organisms from the effects of a second stressor, in this case, ivermectin. Ivermectin and high temperature increased metabolic rate, which could have potential negative effects on oxidative stress and longevity. Finally, critical thermal maximum was not affected by ivermectin or temperature. By impacting physiological traits and individual survival, high temperatures and pesticides may disrupt population dynamics and ecosystem services provided by dung beetles.

Enhancement of alfalfa growth resistance by arbuscular mycorrhiza and earthworm in molybdenum-contaminated soils: From the perspective of soil nutrient turnover

Molybdenum (Mo) acts as a crucial nutrient for plant development, yet excessive soil exposure can cause detrimental effects. Molybdenosis symptoms remain subtle in many plants, largely due to the safeguarding functions of soil organisms, the fundamental biological mechanisms lack clarity. In this study, we explored the potential mechanisms for amending Mo-exposed soils with soil microbe-arbuscular mycorrhizal fungi (AMF) and soil fauna, specifically earthworms, to enhance model plant-alfalfa growth resistance through soil nutrient turnover perspectives. Our findings illustrated that excessive Mo exposure disrupted soil nutrient turnover, manifesting as exacerbated soil microbial C and N metabolic limitations. Consequently, this interference intensified nutrient competition between alfalfa and soil microbes, thereby impeding alfalfa nutrient accumulation and growth resistance. The synergistic application of AMF and earthworms alleviated microbial C (8.55%-28.23%) and N (11.14%-37.55%) metabolic limitations by modulating soil enzyme activities, particularly P-acquiring enzyme. This co-application facilitated enhanced C and N accumulation in alfalfa, thus improving its growth resistance (24.15%-123.74%) under Mo exposure. Furthermore, in contrast to singular treatments, the combination of AMF and earthworms enhanced mutual Mo tolerance, amplifying biological benefits for alfalfa growth. Earthworms promoted AMF colonization and the secretion of glomalin-related soil proteins (GRSP), while AMF alleviated Mo accumulation and oxidative stress in earthworms. Additionally, the AMF-induced regulation of gut metabolism reduced earthworm mortality and minimized weight loss. Our study underscores the necessity of maintaining soil biodiversity when utilizing Mo fertilizers to mitigate the potential risks of Mo over-exposure affecting soil nutrient turnover and plant growth.

The Establishment of a Terrestrial Macroalga Canopy Impacts Microbial Soil Communities in Antarctica

Prasiola is a genus of foliose green algae that forms extensive cryptogamic canopies that contribute to the greening of ice-free areas in the Antarctic tundra. To better understand the impact of Prasiola canopy establishment on colonization in these areas, this study compared the taxonomic and functional structures of bacterial and fungal communities in adjacent soils with and without extensive Prasiola colonization. DNA metabarcoding was employed to analyze the microbial community structure in these soils and in the canopy. Additionally, a phylogenetic study of Prasiola samples was conducted to characterize the taxonomic composition of the analyzed canopies, revealing the presence of Prasiola crispa (Lightfoot) Kützing and P. antarctica Kützing. Key soil attributes were assessed to examine the canopy's influence. Higher pH and carbon, nitrogen, and organic matter contents were found in Prasiola-covered soils than in bare soils. Furthermore, Prasiola canopy establishment not only influenced abiotic soil properties but also shaped soil microbial community structure and its functions. For instance, while Actinobacteriota predominated in bacterial communities both within the Prasiola canopy and beneath it, Bacteroidota dominated in the bare soil. Despite significant variability across soil types, fungal communities showed a trend of higher abundances in certain Ascomycetes, such as Helotiales, Hypocreales, or Xylariales, in soils beneath Prasiola compared to bare soils. Regarding functional diversity, covered soils exhibited a statistically significant lower potential for bacterial methanogenesis and autotrophic CO2 fixation compared to bare soils. Finally, lichenized fungi, plant pathogens, and fungal wood saprotrophs tended to be more abundant in covered soils.

Vegetation types shape the soil micro-food web compositions and soil multifunctionality in Loess Plateau

Introduction

Vegetation degradation and soil erosion are severe problems in the Loess hilly region, rendering it one of the most ecologically vulnerable areas in China and globally. Vegetation restoration has been recognized as an effective approach to amending the fragile ecological environment and restoring degraded ecosystems.

Methods

The effects of different vegetation types: Caragana korshinskii, Prunus armeniaca L., Pinus tabuliformis Carrière, Medicago sativa L., and the control vegetation Stipa bungeana on soil micro-food webs and soil multifunctionality, as well as their response mechanisms to soil environmental drivers, were investigated using High-throughput sequencing technology.

Results

C. korshinskii significantly enhanced soil physicochemical properties and soil enzyme activities by facilitating the stability of the soil micro-food web structure driven by soil bacteria and fungi and increasing the soil multifunctionality in contrast to S. bungeana. Prunus armeniaca also improved soil multifunctionality by promoting soil organic carbon and alkaline phosphatase activity. However, the stability of the soil micro-food web structure and soil multifunctionality were suboptimal in P. tabuliformis and M. sativa. Soil pH, along with carbon, nitrogen, and phosphorus cycling nutrients and enzymes, profoundly influences the structure of the soil micro-food web and soil multifunctionality; among these factors, those related to the carbon and phosphorus cycles are identified as key influencing factors.

Discussion

Therefore, a vegetation restoration strategy prioritizing C. korshinskii as the dominant vegetation type, supplemented by P. armeniaca, significantly impacts restoring soil multifunctionality and stabilizing the soil micro-food web in Loess hill regions and comparable ecological areas.

Plant Biomass Allocation-Regulated Nitrogen and Phosphorus Addition Effects on Ecosystem Carbon Fluxes of a Lucerne (Medicago sativa ssp. sativa) Plantation in the Loess Plateau

Nitrogen (N) and phosphorus (P) are key limiting factors for carbon (C) fluxes in artificial grasslands. The impact of their management on ecosystem C fluxes, including net ecosystem productivity (NEP), ecosystem respiration (ER), and gross ecosystem productivity (GEP) in the Loess Plateau is unclear. An experiment was conducted to study changes in these C fluxes with varying N (0, 5, 10, 15, and 20 g N m-2) and P (0 and 10 g P m-2) additions from 2022 to 2023 in a lucerne plantation. Results showed that N addition positively influenced NEP and GEP in the first year after planting with N addition at the rate of 10 g N m-2 was optimal for C assimilation, but it had negligible effect on ER in both two years in the studied lucerne (Medicago sativa ssp. sativa) plantation. Phosphorus addition significantly increased ER and stimulated GEP, resulting in an increasing effect on NEP only at the early stage after planting. The addition of N and P enhanced soil N and P availability and further improved the leaf chemical stoichiometry characteristics, leading to changes in biomass distribution. The more belowground biomass under N addition and more aboveground production under P addition resulted in different responses of ecosystem C fluxes to N and P addition. The results suggest that the effects of N and P fertilization management on the ecosystem C cycle may be largely dependent on the distribution of above- and belowground plant biomass in the artificial grassland ecosystem.

Wild bee diversity of the National Park of the Semois Valley (Belgium)

Background

Wild bees are essential pollinators, yet their decline due to human activities threatens ecosystem stability. Protecting these pollinators requires a detailed understanding of both their diversity and distribution. In Belgium, the recently-established Semois Valley National Park (SVNP) is located in a region with limited bee sampling data and this study aims to identify the habitats most suitable to bees, especially for threatened species.

New information

Over five months, we surveyed 32 sites and collected a total of 1,119 specimens belonging to 120 bee species. Twenty-two of the observed species are listed as threatened in Belgium according to the last Red List published in 2019 for the country, four of them being Critically Endangered. Our findings indicate that mesic grasslands support the highest species diversity, as well as the highest number of threatened species. Our results underscore the need for conservation efforts aimed at maintaining diversity and species richness in this region. Effective biodiversity preservation will require enhanced habitat management and strategies tailored to bee species' ecological requirements.

Managed honeybees and soil nitrogen availability interactively modulate sunflower production in intensive agricultural landscapes of China

Insects provide important pollination services for cops. While land use intensification has resulted in steep declines of wild pollinator diversity across agricultural landscapes, releasing managed honeybees has been proposed as a countermeasure. However, it remains uncertain whether managed honeybees can close the pollination gap of sunflower (Helianthus annuus L. [Asterales: Asteraceae]) in areas lacking wild pollinators, and how the benefits of honeybees to sunflower production are modulated by soil nutrients. We investigated the effects of 3 pollination treatments (open, self and hand pollination) on sunflower yield parameters. We also estimated the pollination efficiency of managed honeybees (Apis mellifera L. [Hymenoptera: Apidae]), and analyzed the effects of honeybee visitation and soil nitrogen on sunflower yield parameters. Insect pollinators contributed 73% of seed set and 69% of the weight of filled seeds per head in the open pollination of sunflowers, but large pollination deficits still existed. Insect pollination may enhance sunflower yield by augmenting the number and weight of filled seeds per head, but not by altering the total number of seeds. Except for the total number of seeds per head, yield parameters increased significantly with the number of honeybee visits. Low nitrogen accelerated the positive effect of honeybee pollination on sunflowers, and alleviated the negative effect of distance of beehives on honeybee visitation rate. We conclude that managed honeybees could be used to pollinate sunflowers in areas with the shortage of wild pollinators, and sunflower production may benefit from shortening the distance of beehives and lowing of nitrogen fertilizer inputs.

New steroid and meroterpenoids from a sewage fungus Eurotium sp

A new steroid, eurotether (1), and three new meroterpenoids, tricycloalternarene I (2), tricycloalternarene J (3) and (2R,3S,4aR)-altenuene-2-acetoxy ester B (4), along with six known compounds (5-10) were isolated from a sewage fungus Eurotium sp. XL-0006. Their structures were elucidated based on NMR analysis, electronic circular dichroism (ECD) calculations and single crystal X-ray diffraction experiments. Compound 1 was the first example of steroid combined with a dibenzo-α-pyrone through double oxygen bridges, and compounds 1-10 were first discovered from Eurotium genus. Compounds 1-6 were evaluated for antibacterial activities against eight clinical drug-resistant bacteria using the microbroth dilution method.