Leger RJ. Latitudinal Clines in Climate and Sleep Patterns Shape Disease Outcomes in Drosophila melanogaster Infected by Metarhizium anisopliae

Major latitudinal clines have been observed in Drosophila melanogaster, a human commensal that originated in tropical Africa and has subsequently dispersed globally to colonize temperate habitats. However, despite the crucial role pathogens play in species distribution, our understanding of how geographical factors influence disease susceptibility remains limited. This investigation explored the effects of latitudinal clines and biomes on disease resistance using the common fly pathogen Metarhizium anisopliae and 43 global Drosophila melanogaster populations. The findings revealed correlations between disease resistance and latitudinal gradients of sleep duration, temperature, and humidity. Although enhanced defenses may be driven by fungal diversity at tropical latitudes, the most disease-resistant tropical males also showed the highest susceptibility to desiccation. This suggests potential trade-offs between abiotic stress resistance, necessary for survival in temperate habitats, and disease resistance. Furthermore, the study uncovered interactions between sex, mating status, sleep, and abiotic stresses, affecting disease resistance. Notably, longer-sleeping males and virgin flies survived infections longer, with additional daytime sleep post-infection being protective, particularly in the most resistant fly lines. These observations support the hypothesis that sleep and disease defense are intertwined traits linked to organismal fitness and subject to joint clinal evolution.

How to develop causal directed acyclic graphs for observational health research: a scoping review

Causal directed acyclic graphs (DAGs) serve as intuitive tools to visually represent causal relationships between variables. While they find widespread use in guiding study design, data collection and statistical analysis, their adoption remains relatively rare in the domain of psychology. In this paper we describe the relevance of DAGs for health psychology, review guidelines for developing causal DAGs, and offer recommendations for their development. A scoping review searching for papers and resources describing guidelines for DAG development was conducted. Information extracted from the eligible papers and resources (n = 11) was categorised, and results were used to formulate recommendations. Most records focused on DAG development for data analysis, with similar steps outlined. However, we found notable variations on how to implement confounding variables (i.e., sequential inclusion versus exclusion). Also, how domain knowledge should be integrated in the development process was scarcely addressed. Only one paper described how to perform a literature search for DAG development. Key recommendations for causal DAG development are provided and discussed using an illustrative example.

Temperature-dependent responses to light and nutrients in phytoplankton

Nutrients and light are major resources controlling growth, biomass, and community structure of phytoplankton. When looking at those resources individually, resource uptake and biochemical transformation, and thereby also the demand for resources, have been shown to be temperature-dependent. However, there is still a lack of understanding of how temperature controls the response to multiple resources, although simultaneous limitation by multiple resources is common for single species and whole communities. We conducted a multifactorial, gradient-design experiment growing four freshwater phytoplankton species under 125 combinations of temperature, light, and nutrients (5 × 5 × 5 levels). In three of four species, we found evidence for an interactive effect of light and nutrients on growth that was modulated by temperature. The effect of high-level supply of both resources on algal growth rate generally exceeded the sum of their individual effects. Conversely, the lowest growth rates occurred not necessarily at the lowest level of both resources but at the most extreme light:nutrient supply ratios (either only light or nutrients were at highest supply level but the other resource remained at low supply). These interactive light-nutrient effects were modulated by temperature, resulting in highest growth rates when both resources and temperature were highest. Our study demonstrates that temperature modulates the magnitude of the interactive light-nutrient effect on phytoplankton growth. Consequently, these findings highlight the importance of considering temperature to understand the limitation by multiple resources and show that growth responses would be over- or underestimated when these interactions are not taken into account. Our results provide a first indication that the resource-dependent growth of phytoplankton will change in a warming world when considering multiple resources.

Traits estimated when grown alone may underestimate the competitive advantage and invasiveness of exotic species

Functional differences between native and exotic species, estimated when species are grown alone or in mixtures, are often used to predict the invasion risk of exotic species. However, it remains elusive whether the functional differences estimated by the two methods and their ability to predict species invasiveness (e.g. high abundance) are consistent. We compiled data from two common garden experiments, in which specific leaf area, height, and aboveground biomass of 64 common native and exotic invasive species in China were estimated when grown individually (pot) or in mixtures (field). Exotic species accumulated higher aboveground biomass than natives, but only when grown in field mixtures. Moreover, aboveground biomass and functional distinctiveness estimated in mixtures were more predictive of species persistence and relative abundance in the field mixtures in the second year than those estimated when grown alone. These findings suggest that assessing species traits while grown alone may underestimate the competitive advantage for some exotic species, highlighting the importance of trait-by-environment interactions in shaping species invasion. Therefore, we propose that integrating multi-site or multi-year field surveys and manipulative experiments is required to best identify the key trait(s) and environment(s) that interactively shape species invasion and community dynamics.

Do pollinators play a role in shaping the essential amino acids found in nectar?

Plants produce floral nectar as a reward for pollinators, which contains carbohydrates and amino acids (AAs). We designed experiments to test whether pollinators could exert selection pressure on the profiles of AAs in nectar. We used HPLC to measure the free AAs and sugars in the nectar of 102 UK plant species. Six distinct profiles of essential amino acids (EAAs) were defined using the relative proportions of AAs with a clustering algorithm; we then tested bumblebee (Bombus terrestris) preferences for the EAA profiles and proline using a two-choice assay. We found a phylogenetic signal for the proportions of phenylalanine, methionine and proline as well as the total concentrations of essential and nonessential amino acids. However, there was no phylogenetic signal for EAA profile. Bumblebees did not exhibit a preference for any of the six EAA nectar profiles; however, four of the EAA profiles stimulated feeding. By contrast, bumblebees avoided proline in an inverse concentration-dependent manner. Our data indicate that bees are likely to have mechanisms for the postingestive evaluation of free AAs in solution but are unlikely to taste EAAs at nectar-relevant quantities. We predict that EAAs increase nectar value to bumblebees postingestively.

A bacteria-based index of biotic integrity assesses aquatic ecosystems effectively in rewetted long-term dry river channel after water replenishment

Climate-induced droughts exert a significant influence on the connectivity of river systems. It is estimated that about 25% of the world's rivers ran dry before reaching the ocean due to climate change and human activities. Ecological water replenishment is an effective measure for restoring aquatic ecosystems damaged by drought. It is urgently needed to quantitatively assess the aquatic ecosystems in rewetted dry river channels after water replenishment. This study investigated the variations in phytoplankton, zooplankton, benthic macroinvertebrates, and benthic bacterial communities in the rewetted dry river channel of Yongding River after water replenishment. In comparison with the water column communities, the benthic macroinvertebrates were identified as limiting factors for ecological restoration in rewetted dry river channels. In the absence of a certain recovery time for benthic macroinvertebrates, the benthic bacterial-based index of biological integrity, especially calculated based on their intrinsic properties, can properly assess aquatic ecosystems in rewetted dry river channels.

Operational Stress Injuries in Disaster Responders: A Framework for Supporting Mental Health in Climate Crisis

The rising occurrence of natural disasters linked to climate change has drawn the attention of disaster response leaders to the significance of addressing operational stress injuries among disaster response personnel. We define and describe operational stress injuries in this workforce and explore theoretical frameworks that can inform the development of programs and interventions to mitigate these effects. We aim to establish a conceptual framework for understanding an operational stress injury by introducing a model specific to disaster responders. We also emphasize strategies that can be employed within a stress injury awareness framework to promote the mental well-being of those who respond to climate-related disasters.

Predicting end-of-season timing across diverse North American grasslands

Climate change is altering the timing of seasonal vegetation cycles (phenology), with cascading consequences on larger ecosystem processes. Therefore, understanding the drivers of vegetation phenology is critical to predicting ecological impacts of climate change. While numerous phenology models exist to predict the timing of the start of the growing season (SOS), there are fewer end-of-season (EOS) models, and most perform poorly in grasslands, since they were made for forests. Our objective was to develop an improved EOS grassland phenology model. We used repeat digital imagery from the PhenoCam Network to extract EOS dates for 44 diverse North American grassland sites (212 site-years) that we fit to 20 new and 3 existing EOS models. All new EOS models (RMSE = 22-33 days between observed and predicted dates) performed substantially better than existing ones (RMSE = 43-46 days). The top model predicted EOS after surpassing a threshold of either accumulated cold temperatures or dryness, but only after a certain number of days following SOS. Including SOS date improved all model fits, indicating a strong correlation between start- and end-of-season timing. Model performance was further improved by independently optimizing parameters for six distinct climate regions (RMSE = 4-19 days). While the best model varied slightly by region, most included similar drivers as the top all-sites model. Thus, across diverse grassland sites, EOS is influenced by both weather (temperature, moisture) and SOS timing. Incorporating these new EOS models into Earth System Models should improve predictions of grassland dynamics and associated ecosystem processes.

Plant-pollinator trait matching affects pollen transfer but not feeding efficiency of Australian honeyeaters (Aves, Meliphagidae)

Animal pollination is common among flowering plants. Increased morphological matching between floral and pollinator traits is thought to increase pollen transfer and feeding efficiency, but we lack studies that empirically demonstrate this. Working with Australian honeyeaters, we find that there is positive correlation between bill-corolla matching and pollen deposition at flowers, but no correlation with how efficiently birds can extract floral nectar. The species with the lowest bill-corolla matching deposited the fewest pollen grains but had the highest feeding efficiency, showing that bill-corolla matching expectations were met on the plant side of this interaction but not on the pollinator side. Finally, we find different interspecific patterns of pollen deposition at the scales of a single flower visit versus the landscape, due to differences in patterns of plant visitation. This work illustrates the need for more studies that directly correlate trait matching to fitness proxies of plants and avian pollinators.

Soil cadmium pollution elicits sex-specific plant volatile emissions in response to insect herbivory in eastern cottonwood Populus deltoides

Soil heavy metal pollution is a major abiotic stressor frequently encountered by plants in conjunction with other biotic stresses like insect herbivory. Yet, it remains largely unexplored how soil metal pollution and insect herbivory act together to influence emissions of plant volatile organic compounds (VOCs), which mediate multiple ecological functions and play crucial roles in atmospheric processes. Here, we assessed the individual and combined effects of soil cadium (Cd) pollution and insect herbivory by Clostera anachoreta on VOC emissions from the seedlings of eastern cottonwood Populus deltoides, and whether these effects depend on plant sex. We found that plant sex notably influenced VOC emission and altered blend compositions, with male seedlings emitting higher amounts of monoterpenes, sesquiterpenes, homoterpenes and green leaf volatiles (GLVs) than females. Soil Cd exposure significantly increased emissions of monoterpenes, GLVs, and nitrogenous VOCs in males but not in females. Comparatively, larval feeding exerted the strongest effects on VOC emissions and their composition, albeit to varying extent between males and females, and among different VOC classes. Importantly, Cd exposure amplified herbivore-induced VOC emissions in males. For instance, under both Cd and herbivory conditions, male seedlings showed a 68.1-fold increase in nitrogenous VOC emissions, almost twice the combined effects of Cd (8.7-fold) and herbivory (26.3-fold). Taken together, these results suggest that soil metal pollution can boost herbivore-induced VOC emissions in a sex-specific manner, with potential implications for ecological interactions and atmospheric processes.

Decoding the drivers of variability in chlorophyll-a concentrations in the Pearl River Estuary: Intra-annual and inter-annual analyses of environmental influences

Temporal variability and associated driving factors of sea surface chlorophyll-a concentration (Chl-a) in coastal waters have been extensively studied worldwide; however, the importance and spatial heterogeneity of these driving factors remain insufficiently documented. This study addressed this gap by investigating the Pearl River Estuary (PRE) from August 2002 to June 2016, using long-term remote sensing-derived data of Chl-a and potential driving factors, including total suspended solids (TSS), precipitation, photosynthetically active radiation (PAR), and sea surface temperature (SST); and in situ measurements of potential driving factors, including river discharge, wind speed, alongshore wind (u), cross-shore wind (v), and tidal range. A pixel-by-pixel correlation analysis was conducted to preliminarily examine the relationships between these potential driving factors and Chl-a. Subsequently, random forest regression was applied to determine the primary factors in driving the intra-annual and inter-annual variations of Chl-a. Results indicate that, at the intra-annual scale, TSS was the primary factor influencing Chl-a in the shallow (<10 m) nearshore regions and the deep (>30 m) offshore regions, while SST was most important in the intermediate zone. Additionally, in certain areas of the Lingding Bay, Chl-a was primarily affected by river discharge. At the inter-annual scale, tidal range was the primary factor in the western Lingding Bay and the western coastal waters, while Chl-a was primarily modulated by SST in the eastern Lingding Bay. In the offshore region, Chl-a was primarily modulated by river discharge, v, precipitation, and TSS. These findings are of fundamental importance for advancing our understanding of the characteristics and associated mechanisms of marine environmental variability in estuarine systems. They provide a scientific basis for informed management of estuarine environments and sustainable economic development.

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.

Microbial mechanisms of interactive climate-driven changes in soil N2O and CH4 fluxes: A global meta-analysis

Soils represent both a source of and sink for greenhouse gases (GHG). Elevated temperature (eT) affects both the physical and biological factors that drive GHG emissions from soil and thus understanding the effects of rising global temperatures on terrestrial GHG emission is needed to predict future GHG emissions, and to identify mitigation strategies. However, uncertainty remains about the interactive effects of multiple climate factors across different ecosystems, complicating our ability to develop robust climate change projections. Therefore, a global meta-analysis of 1337 pairwise observations from 150 peer-reviewed publications (1990-2023) was conducted to assess the individual effect of eT and its combined effects with eCO2 (eT + eCO2), drought (eT + drought) and increased precipitation (eT + ePPT) on soil N2O and CH4 fluxes, microbial functional genes, and soil extracellular enzyme activities across grassland, cropland, and forestland ecosystems. Across the dataset, eT significantly increased N2O emissions (21%) and CH4 uptake (36%). Nitrogen cycling was consistently stimulated by eT, with NO3- and NH4+ and the abundance of amoA-AOB gene increasing by 6%, 10%, and 18%, respectively. Soil water content (SWC) was reduced, whereas increases of 9% in soil organic carbon (SOC), 14% in microbial biomass carbon (MBC), and 10% in total plant biomass were found under eT. The stimulation of soil N2O emissions by eT was maintained for all ecosystems when combined with other global change factors (ie., eT + eCO2, eT + ePPT, and eT + drought). By contrast, effects of eT on CH4 uptake and emissions were more variable when combined with other factors; for instance, eT + eCO2 and eT + ePPT suppressed CH4 uptake in grasslands. This study highlights the urgent need to study the microbial mechanisms responsible for combined global change effects on N2O and especially CH4 fluxes.

District ammonium-to-nitrate ratios change soil N dynamics and shape inverse patterns of resource acquisition strategy and biomass production of four urban greening trees

Ammonium nitrogen (NH4+) and nitrate nitrogen (NO3-), the primary soil accessible nitrogen (N) forms for most plants, can affect plant ecophysiology and biomass production in different ways. Plants typically exhibit varying capacities for uptake and assimilation of the two N forms, leading to differences in the ecological strategies and niches within ecosystem. Recently, variations in atmospheric NH4+/NO3- deposition have severely threatened plant growth and ecosystem functions, especially in urban green spaces. Therefore, a pot experiment was carried out to explore the response of four common urban greening tree species (Pinus tabulaeformnis, Juniperus chinensis, Fraxinus chinensis, Sophora japonica) in North China, to five NH4+/NO3- addition treatments. Our results indicated that trees could adapt to varying soil N environments by modifying their resource acquisition strategies and biomass production, where the response patterns depended on the species specificity. High NH4+/NO3- addition increased soil urease activity and NH4+/NO3- ratios planted to coniferous trees, enhancing the plant fast traits highly coordinated across different organs, which promoted the plant growth. While broadleaved tree species exhibited stronger plasticity under NO3--rich conditions. Reduced NH4+/NO3- ratios increased soil NO3- and available phosphorus availability, improving their resource acquisition capacity and root nitrate reductase activity, which favored NO3- utilization and biomass production. Overall, this study highlights the importance of plant resource acquisition strategy in driving the responses of biomass production to soil N dynamic changes and puts forward a new growth strategy for urban greening tree species in the plant-soil feedback system.

Predicting the global economic costs of biological invasions by tetrapods

Globalisation has accelerated rates of biological invasions worldwide, leading to widespread environmental perturbations that often translate into rapidly expanding socio-economic costs. Although such monetary costs can be estimated from the observed effects of invasions, the pathways that lead invasive species to become economically impactful remain poorly understood. Here, we implement the first global-scale test of the hypothesis that adaptive traits that influence demographic resilience predict economic costs, using invasive terrestrial vertebrates as models given their well-catalogued impacts and characteristics. Our results reveal that total global costs of invasive tetrapods are conservatively in the tens of billions of dollars, with the vast majority due to damage costs from invasive mammals. These monetary impacts are predicted by longevity, female maturation age, diet and invasion pathway traits, although the directionality in the association between impacts and these drivers varied across classes. Alarmingly, costs remain unknown for >90 % of recorded established alien tetrapods worldwide, and across the majority of invaded countries. These huge socio-economic costs demonstrate the necessity of mitigating tetrapod invasions and filling knowledge gaps. Effective identification of traits predictive of costs among and within these groups can facilitate the prioritisation of resources to efficiently target the most damaging existing and emerging invasive tetrapod species.

Land use types, basin characteristics and water quality together shape riverine phytoplankton community composition and diversity

Exploring the combined effects of basin characteristics, land use types, and human activities on phytoplankton biomass, community composition and diversity is important for developing effective river protection strategies. In the present study, 182 phytoplankton samples were collected in the Hanjian and Danjiang River basins and the explanation rate of the above factors was analyzed. Water quality was the primary factor affecting riverine phytoplankton biomass, with an explanation rate to Chl a reaching 59.8%. Water quality was also the primary factor affecting phytoplankton diversity but the contribution of land use types and basin characteristics was also high. In addition to affecting phytoplankton communities and diversity by affecting water quality, diverse land use can increase the taxa of algae discharged through soil erosion processes. Elevation and slope were the main basin characteristics regulating phytoplankton community and diversity because they can determine the retention time of phytoplankton in rivers. The results also showed that land use types were the primary factor affecting the critical relative abundance of extinction (a), competition coefficient (k), environmental taxa capacity (N), but water quality was the primary factor affecting Shannon index, Simpson index, and Pielou index. This difference indicated that index a, k, and N could reflect specific characteristics of phytoplankton diversity that were not reflected by the latter indices. Our results implied that land use types and basin characteristics affected the discharge of exotic algal taxa, retention time, and other factors, thereby influencing the composition and diversity of riverine phytoplankton communities.

Intramolluscan stages of digeneans parasitizing the pest apple snail Pomacea canaliculata from Argentina: Molecular identification and histopathology

Pomacea canaliculata is a highly successful invasive snail that shapes freshwater communities in both native and invaded habitats. We studied its digenean parasites from three freshwater bodies in its native distribution area in Buenos Aires Province, Argentina. An integrated approach was used to determine and describe the larval stages of digenean, including morphological, molecular, and histopathology analyses. We provide the first record of P. canaliculata as the first intermediate host of Stomylotrema vicarium (Stomylotrematidae), two species of the family Phaneropsolidae, and one species of the family Cyclocoelidae. This is also the first record of a species of the family Cyclocoelidae parasitizing snails of the genus Pomacea, with the apple snail acting as both the first and second intermediate host. The digestive gland was identified as the target organ of infection for all species. Stomylotrema vicarium and Phaneropsolidae gen. et sp. 2 alter the structure of the gonads, causing indirect parasitic castration, and, through mechanical compression, destroying also the digestive gland. Adequate knowledge of the identity and dynamics of the parasites affecting P. canaliculata in its native range and the damage they cause is key to explaining the success of this invasive species. The lack of parasite records in invaded areas supports the "enemy release" hypothesis, which could explain the apple snail's success in these environments. Parasitic castration reduces the reproductive potential of hosts, limiting the expansion and competition of invasive species, making it crucial to understand these impacts for their conservation and control.

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.

An antennal-specific OBP mediates bait odorant perception in fire ants

Odorant binding proteins (OBPs) play a key role in the crosstalk between the external environment and dendritic neuron activation. Ham sausage is an efficient bait widely used for monitoring the invasive ant Solenopsis invicta in the field, whereas the chemoreceptors involved in bait odorant perception in S. invicta have not been functionally characterized. Here, we investigated the role of SiOBP2, an OBP specifically expressed in the antenna, from S. invicta in detecting bait odorants. SiOBP2 was specifically expressed in sensillum basiconca in S. invicta antennae and displayed strong binding affinity and diverse binding mechanisms with specific bait odorants, such as static quenching and multiple binding characteristics with 3-mercapto-2-butanone and furfuryl mercaptan. Knockdown of SiOBP2 abolished the electroantennogram and behavioral responses of S. invicta to these odorants. S. invicta with SiOBP2 knockdown exhibited inactivation of odorant receptor neuron signaling and reduced bait searching efficiency. Foraging behavior and sensory cone responses to bait odorant stimuli in S. invicta demonstrate the sensillum basiconca is particularly tuned to 3-mercapto-2-butanone and furfuryl mercaptan. Collectively, SiOBP2 is essential for the perception of S. invicta on bait odorants and can be used as an important molecular target to develop novel attractants for S. invicta.

Wind Is a Primary Driver of Fungal Dispersal Across a Mainland-Island System

Dispersal is one of the main processes shaping ecological communities. Yet, for species-rich communities in natural systems, the role of dispersal in community assembly remains relatively less studied compared to other processes. This is the case for fungal communities, for which predictable knowledge about where and how the dispersal propagules move across space is largely lacking. We sampled fungal communities at their dispersal stage in a lake mainland-island system in Finland, using a regular grid of 18 × 18 km, including sites on the mainland, islands and over the water. Fungal communities were screened by applying DNA barcoding to air samples. To assess the factors determining fungal dispersal, we modelled aerial fungal communities with a joint species distribution model, including spore traits, weather-related predictors, and spatial predictors. We found that the probability of occurrence of most species (and consequently species richness measured as the number of OTUs per sample) was lower in low-connectivity sites (water and isolated islands) compared to high-connectivity sites (mainland). There was a strong phylogenetic signal in how the fungal species responded to connectivity, indicating that some taxonomic groups are more dispersal limited than others, although such responses were not structured by their trophic guilds. Furthermore, wind speed influenced how species with different spore sizes responded to connectivity: in low-connectivity sites, species with large sexual spores were detected especially when wind was high, whereas, in high-connectivity sites, they were detected especially when wind was low. This study demonstrates that air fungal dispersal might be more predictable than previously considered and contributes to the mechanistic understanding of fungal air dispersal.

Hemocyanin contributes to embryonic adaptation to hypoxia in the migratory locust

Ambient hypoxia can pose a major threat to the survival of metazoan organisms, especially insect embryos. Hemocyanin exhibits dominant expression in insect embryos, but its specific roles in hypoxia adaptation remain unexplored. Soil-dwelling locust eggs may frequently experience hypoxia during development. A comprehensive analysis of physiological and biochemical characters of hemocyanin was conducted in the embryos of migratory locust Locusta migratoria. Our results demonstrated that the revolution process was the critical hypoxia-sensitive event during locust embryogenesis. Hemocyanin presented a prominent expression in the revolution stage and exhibited strong responses to hypoxia. The relative duration of revolution was correlated negatively with the expression of hemocyanin subunit 2 (HC2), suggesting that HC2 might be closely associated with hypoxia adaptation of locust embryos. Furthermore, a HC2 mutant locust strain was established using the CRISPR/Cas9 technology, and higher hypoxia sensitivity was found for HC2-deficient locust embryos. Knockdown of HC2 increased anaerobic metabolism and oxidative stress while reducing oxidative metabolism. Overall, these findings clearly demonstrated the pivotal roles of hemocyanin in hypoxia adaptation of insect embryos.

Spatiotemporal patterns and alleviating of grassland overgrazing under current and future conditions in Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau (QTP) is a crucial region for biodiversity conservation and global ecosystem services supply, and its grassland carrying capacity (GCC) is directly related to both herders' livelihoods and the implementation of ecosystem conservation and restoration programs. However, the spatiotemporal distribution of GCC within the QTP and grasslands' responses to future climate change remain unclear. Here, we evaluated the spatiotemporal characteristics of GCC for 60 years and its load during 2000-2020, and then classified levels of early-warning based on whether the grassland is currently overgrazed, and whether the overgrazing is increasing over time. Results showed that (1) GCC increased from 86.15 million to 97.70 million sheep units (SU) during 2000-2020, and GCC was higher in the east than that in the west QTP. (2) Overgrazing was alleviated due to livestock reduction after 2010 and GCC has grown more, but remains serious. The counties with stronger GCC showed more serious overgrazing. (3) Annual mean GCC was projected to increase by 0.05 SU·km-2 and 1.22 SU·km-2 under Shared Socioeconomic Pathways (SSPs) 126 and SSP460, respectively. Overgrazing is likely to be greatly alleviated in the future with climate change and livestock reductions in the QTP. Our study gives practical advice for adjusting the development pattern of grassland animal husbandry and provides recommendations for key implementation areas of ecosystem conservation and restoration programs of grassland ecosystems.

Resolving the contrasting leaf hydraulic adaptation of C3 and C4 grasses

Grasses are exceptionally productive, yet their hydraulic adaptation is paradoxical. Among C3 grasses, a high photosynthetic rate (Aarea) may depend on higher vein density (Dv) and hydraulic conductance (Kleaf). However, the higher Dv of C4 grasses suggests a hydraulic surplus, given their reduced need for high Kleaf resulting from lower stomatal conductance (gs). Combining hydraulic and photosynthetic physiological data for diverse common garden C3 and C4 species with data for 332 species from the published literature, and mechanistic modeling, we validated a framework for linkages of photosynthesis with hydraulic transport, anatomy, and adaptation to aridity. C3 and C4 grasses had similar Kleaf in our common garden, but C4 grasses had higher Kleaf than C3 species in our meta-analysis. Variation in Kleaf depended on outside-xylem pathways. C4 grasses have high Kleaf : gs, which modeling shows is essential to achieve their photosynthetic advantage. Across C3 grasses, higher Aarea was associated with higher Kleaf, and adaptation to aridity, whereas for C4 species, adaptation to aridity was associated with higher Kleaf : gs. These associations are consistent with adaptation for stress avoidance. Hydraulic traits are a critical element of evolutionary and ecological success in C3 and C4 grasses and are crucial avenues for crop design and ecological forecasting.

Modelling soil organic carbon at multiple depths in woody encroached grasslands using integrated remotely sensed data

Woody plants encroachment into grasslands has considerable hydrological and biogeochemical consequences to grassland soils that include altering the Soil Organic Carbon (SOC) pool. Consequently, continuous SOC stock assessment and evaluation at deeper soil depths of woody encroached grasslands is essential for informed management and monitoring of the phenomenon. Due to high litter biomass and deep root structures, woody encroached landscapes have been suggested to alter the accumulation of SOC at deeper soil layers; however, the extent at which woody plants sequester SOC within localized protected grasslands is still poorly understood. Remote sensing methods and techniques have recently been popular in SOC analysis due to better spatial and spectral data properties as well as the availability of affordable and eco-friendly data. In this regard, this study sought to quantify the accumulation of SOC at various depths (30 cm, 60 cm, and 100 cm) in a woody-encroached grassland by integrating Sentinel-1 (S1), Sentinel-2 (S2), PlanetScope (PS) satellite imagery, and topographic variables. SOC was quantified from 360 field-collected soil samples using the loss-On-Ignition (LOI) method and spatial distribution of SOC across the Bisley Nature Reserve modelled by employing the Random Forest (RF) algorithm. The study's results demonstrate that the integration of topographic variables, Synthetic Aperture Radar (SAR), and PlanetScope data effectively modelled SOC stocks at all investigated soil depths, with high R2 values of 0.79 and RMSE of 0.254 t/ha. Interestingly, SOC stocks were higher at 30 cm compared to 60 cm and 100 cm depths. The horizontal reception (VH), Slope, Topographic Weightiness Index (TWI), Band 11 and vertical reception (VV) were optimal predictors of SOC in woody encroached landscapes. These results highlight the significance of integrating RF model with spectral data and topographic variables for accurate SOC modelling in woody encroached ecosystems. The findings of this study are pivotal for developing a cost-effective and labour-efficient assessment and monitoring system for the appropriate management of SOC in woody encroached habitats.

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.

Deletion of ACC Deaminase in Symbionts Converts the Host Plant From Water Waster to Water Saver

Increasing drought events coupled with dwindling water reserves threaten global food production and security. This issue is exacerbated by the use of crops that overconsume water, undermining yield. We show here that microorganisms naturally associated with plant roots can undermine efficient water use, whereas modified bacteria can enhance it. We demonstrate that microbe-encoded genes shape drought tolerance, likely by modulating plant hormonal balance. Specifically, we built a minimal holobiont out of Arabidopsis thaliana and either the bacterium Pseudomonas putida UW4 or its isogenic AcdS- mutant, lacking the enzyme ACC deaminase. This enzyme breaks down the precursor of ethylene, a key regulator in plant response to drought. This single mutation profoundly affected plant physiology and shifted the plant from a 'water-spender' (with more growth under well-watered conditions) to a 'water-spender' phenotype. Under drought, plants associated with wild-type bacteria consumed soil water faster, leading to a shorter period of growth followed by death. In contrast, plants associated with the AcdS- mutant managed to maintain growth by reducing water consumption via stomatal closure, thus conserving soil water. This allowed plants to survive severe water deficiency. We conclude that plant-associated bacteria can modulate plant water use strategies, opening possibilities to engineer water-savvy crop-production systems.

Calonectris shearwaters reveal a gradient of mercury contamination along the Atlantic and Mediterranean waters of the Iberian Peninsula

This study examines blood mercury (Hg) concentrations in Calonectris spp. shearwaters from three colonies along the Atlantic and Mediterranean waters of the Iberian Peninsula (southwestern Europe), investigating their relationship with foraging ecology through GPS tracking and stable isotopes (δ15N and δ13C) data during the breeding season. Hg levels exhibited a spatial gradient, increasing from the Atlantic Ocean (1.8 ± 0.4 μg g-1 dw) towards the Mediterranean Sea, with shearwaters from the Columbretes Islands (NW Mediterranean) showing the highest Hg levels (6.5 ± 2.1 μg g-1 dw). Individuals breeding in the Alboran Sea, a transition area between both basins, had intermediate Hg concentrations (3.1 ± 1.5 μg g-1 dw). All individuals were above the Hg toxicity threshold associated with negative reproductive, body condition, and immune system outcomes. However, all shearwaters had a Se:Hg molar ratio above 4, indicating effective protection of Se against Hg toxicity. Positive significant relationships between Hg concentrations, δ15N values, and time spent foraging in deep sea waters were observed in Mediterranean colonies, highlighting the ecological context's role in Hg accumulation. Results suggest that feeding on higher trophic level prey, in deep-sea areas, and geographic location contribute to Hg accumulation in these populations. Given the potential health risks associated with elevated Hg levels, further research is warranted to explore the ecological factors driving Hg accumulation and the implications for the health status of these populations.

Mercury contamination in the European green toad Bufotes viridis in Vienna, Austria

Mercury (Hg) contamination affects all ecosystems worldwide. Its deleterious effects on wildlife and humans encompass a diversity of impacts from individual to population levels. In the present study, we quantified Hg concentration across various tissues (blood, brain, muscle, and toe) of green toads (Bufotes viridis) and investigated the use of toe clips as a proxy of Hg concentration in internal tissues, including the brain. Our results show distinct patterns of Hg contamination across tissues, with the highest Hg concentration in the blood with 1.496 ± 0.772 µg.g-1 dry weight (dw), followed by muscle tissue with 0.687 ± 0.376 µg.g-1 dw, brain tissue with 0.542 ± 0.319 µg.g-1 dw, and toes with 0.229 ± 0.143 µg.g-1 dw. A strong relationship has been found between toe and brain Hg concentrations (R2 = 0.857, p < 0.001). These results emphasize the potential of toe clipping as a reliable, non-lethal method for predicting brain Hg concentrations in the green toad. Further, results open the possibility of assessing the potential association between Hg contamination and the cognitive performance of amphibians.

The role of industry 4.0 enabling technologies for predicting, and managing of algal blooms: Bridging gaps and unlocking potential

Recent advancements in data analytics, predictive modeling, and optimization have highlighted the potential of integrating algal blooms (ABs) with Industry 4.0 technologies. Among these innovations, digital twins (DT) have gained prominence, driven by the rapid development of artificial intelligence (AI) and machine learning (ML) technologies, particularly those associated with the Internet of Things (IoT). AI is pivotal in enabling IoT and DT by enhancing decision-making, automating processes, and delivering actionable insights. The intersection of DT and AI in the context of ABs presents a promising new area for research exploration. Digital twins, which serve as virtual replicas of physical entities, systems, or processes, offer significant potential when combined with AI technologies, paving the way for novel research avenues in algal management (AM). This literature review examines digital twins' challenges and applications within AM. It also comprehensively analyzes the current state of IoT-based applications developed using AI and DT. The review further explores the tools for implementing DT systems and surveys existing AI techniques incorporating DTs. Additionally, it discusses the opportunities and challenges associated with creating various IoT-based applications by integrating AI and DT. The review concludes by identifying unexplored research avenues in this emerging field, underscoring the potential for future advancements in Artificial Intelligence of Things (AIoT) within AM.

Detecting context dependence in the expression of life history trade-offs

Life history trade-offs are one of the central tenets of evolutionary demography. Trade-offs, depicting negative covariances between individuals' life history traits, can arise from genetic constraints, or from a finite amount of resources that each individual has to allocate in a zero-sum game between somatic and reproductive functions. While theory predicts that trade-offs are ubiquitous, empirical studies have often failed to detect such negative covariances in wild populations. One way to improve the detection of trade-offs is by accounting for the environmental context, as trade-off expression may depend on environmental conditions. However, current methodologies usually search for fixed covariances between traits, thereby ignoring their context dependence. Here, we present a hierarchical multivariate 'covariance reaction norm' model, adapted from Martin (2023), to help detect context dependence in the expression of life-history trade-offs using demographic data. The method allows continuous variation in the phenotypic correlation between traits. We validate the model on simulated data for both intraindividual and intergenerational trade-offs. We then apply it to empirical datasets of yellow-bellied marmots (Marmota flaviventer) and Soay sheep (Ovis aries) as a proof-of-concept showing that new insights can be gained by applying our methodology, such as detecting trade-offs only in specific environments. We discuss its potential for application to many of the existing long-term demographic datasets and how it could improve our understanding of trade-off expression in particular, and life history theory in general.

Soil microbes influence the ecology and evolution of plant plasticity

Stress often induces plant trait plasticity, and microbial communities also alter plant traits. Therefore, it is unclear how much plasticity results from direct plant responses to stress vs indirect responses due to stress-induced changes in soil microbial communities. To test how microbes and microbial community responses to stress affect the ecology and potentially the evolution of plant plasticity, I grew plants in four stress environments (salt, herbicide, herbivory, and no stress) with microbes that had responded to these same environments or with sterile inoculant. Plants delayed flowering under stress only when inoculated with live microbial communities, and this plasticity was maladaptive. However, microbial communities responded to stress in ways that accelerated flowering across all environments. Microbes also affected the expression of genetic variation for plant flowering time and specific leaf area, as well as genetic variation for plasticity of both traits, and disrupted a positive genetic correlation for plasticity in response to herbicide and herbivory stress, suggesting that microbes may affect the pace of plant evolution. Together, these results highlight an important role for soil microbes in plant plastic responses to stress and suggest that microbes may alter the evolution of plant plasticity.

Low-level PM 2.5 Exposure, Cardiovascular and Nonaccidental Mortality, and Related Health Disparities in 12 US States

BACKGROUND

Investigations into long-term fine particulate matter (PM 2.5 ) exposure's impact on nonaccidental and cardiovascular (CVD) deaths primarily involve nonrepresentative adult populations at concentrations above the new Environmental Protection Agency annual PM 2.5 standard.

METHODS

Using generalized linear models, we studied PM 2.5 exposure on rates of five mortality outcomes (all nonaccidental, CVD, myocardial infarction, stroke, and congestive heart failure) in 12 US states from 2000 to 2016. We aggregated predicted annual PM 2.5 exposures from a validated ensemble exposure model, ambient temperature from Daymet predictions, and mortality rates to all census tract-years within the states. We obtained covariates from the decennial Census and the American Community Surveys and assessed effect measure modification by race and education with stratification.

RESULTS

For each 1-µg/m 3 increase in annual PM 2.5 , we found positive associations with all five mortality outcomes: all nonaccidental (1.08%; 95% confidence interval [CI]: 0.96%, 1.20%), all CVD (1.27%; 95% CI: 1.14%, 1.41%), myocardial infarction (1.89%; 95% CI: 1.67%, 2.11%), stroke (1.08%; 95% CI: 0.87%, 1.30%), and congestive heart failure (2.20%; 95% CI: 1.97%, 2.44%). Positive associations persisted at <8 µg/m 3 PM 2.5 levels and among populations with only under 65. In our study, race, but not education, modifies associations. High-educated Black had a 2.90% larger increased risk of CVD mortality (95% CI: 2.42%, 3.39%) compared with low-educated non-Black.

CONCLUSION

Long-term PM 2.5 exposure is associated with nonaccidental and CVD mortality in 12 states, below the new Environmental Protection Agency standard, for both low PM 2.5 regions and the general population. Vulnerability to CVD mortality persists among Black individuals regardless of education level.

California annual grass phenology and allometry influence ecosystem dynamics and fire regime in a vegetation demography model

Grass-dominated ecosystems cover wide areas of the land surface yet have received far less attention from the Earth System Model (ESM) community. This limits model projections of ecosystem dynamics in response to global change and coupled vegetation-climate dynamics. We used the Functionally Assembled Terrestrial Ecosystem Simulator (FATES), a dynamic vegetation demography model, to determine ecosystem sensitivity to alternate, observed grass allometries and biophysical traits, and evaluated model performance in capturing California C3 annual grasslands structure and fire regimes. Grass allometry, leaf physiology, plant phenology, and plant mortality all drove the seasonal variation in matter and energy exchange and fire dynamics in California annual grasslands. Allometry influenced grassland structure and function mainly through canopy architecture-mediated space and light competition instead of through carbon partitioning strategy. Regional variation in grassland annual burned area was driven by variation in ecosystem productivity. Our study advances the modeling of grassy ecosystems in ESMs by establishing the importance of grass allometry and plant phenology and mortality in driving C3 annual grassland seasonal dynamics and fire regime. The calibrated annual grass allometry and biophysical traits presented can be applied in future studies to project climate-vegetation-fire feedbacks in annual grass-dominant ecosystems under global change.

Alpha and beta diversities of hydrothermal vent macrofaunal communities along the southwestern Pacific back-arc basins

Ecosystems face various pressures, often leading to loss of biodiversity. Understanding how biodiversity is spatially structured, what are the driving factors, and the ecological and evolutionary processes involved is essential to assess communities' resilience to disturbances and guide efficient conservation measures. Hydrothermal vents from national waters of the West Pacific are targeted by mining industries for their mineral resources that include metals used in high-tech equipment. Although exploitation has not yet started, such activity could significantly affect ecosystem biodiversity and functioning. Here, we describe the distribution of hydrothermal biodiversity in the Southwest Pacific back-arc basins and the Futuna Volcanic Arc at different spatial scales in relation to environmental conditions and geography. We focused on three assemblages dominated by symbiotic megafauna: snails (Alviniconcha spp. and Ifremeria nautilei) and mussels (Bathymodiolus spp.). Faunal assemblages exhibit strong spatial structuring: between habitats along the dilution gradient of the hydrothermal fluid, and between geographic basins, with a faunal split between the Western and the Eastern basins of this region, and to a lesser extent, between fields in a basin. Species replacement along the chemical gradient drives faunal changes between Ifremeria and Bathymodiolus assemblages, while a drop in the number of species is noted when making this comparison with the Alviniconcha assemblage. While these local changes may result from environmental filtering along the diffuse flow gradient, geological settings and current geographic barriers, which drive colonization and speciation at larger scales, are likely shaping the vent community changes between the Eastern and Western basins. This result has significant implications for biodiversity conservation, especially in this mineral-rich setting. The Manus Basin is isolated and displays the highest proportion of endemism while the Woodlark Basin represents an important stepping-stone between the Eastern basins and Manus Basin, making them potentially highly vulnerable to mining with a risk of biodiversity loss.

Plant diversity increases diversity and network complexity rather than alters community assembly processes of leaf-associated fungi in a subtropical forest

Plant diversity significantly impacts ecosystem processes and functions, yet its influence on the community assembly of leaf fungi remains poorly understood. In this study, we investigated leaf epiphytic and endophytic fungal communities in a Chinese subtropical tree species richness experiment, ranging from 1 to 16 species, using amplicon sequencing to target the internal transcribed spacer 1 region of the rDNA. We found that the community assembly of epiphytic and endophytic fungi was predominantly governed by stochastic processes, with a higher contribution of dispersal limitation on epiphytic than on endophytic fungal communities but a higher contribution of selection on endophytic than on epiphytic fungal communities. The plant-epiphytic fungus interaction network was more complex (e.g., more highly connected and strongly nested but less specialized and modularized) than the plant-endophytic fungus interaction network. Additionally, tree species richness was positively correlated with the network complexity and diversity of epiphytic (α-, β- and γ-diversity) and endophytic (β- and γ-diversity) fungi, but was not associated with the contribution of the stochastic and deterministic processes on the community assembly of epiphytic and endophytic fungi. This study highlights that tree species diversity enhances the diversity and network complexity, rather than alters the ecological processes in community assembly of leaf-associated fungi.

Soil Cadmium Pollution Decreases Phosphorus-Mineralizing Microbial Diversity and Reduces Phosphorus Availability

Cadmium (Cd) has become a major environmental concern, adversely affecting soil quality and crop productivity. Cd pollution disrupts soil nutrient cycling, particularly phosphorus (P), which is crucial for plant growth. In this study, we conducted a meta-analysis to assess the impact of Cd on soil phosphorus availability, followed by pot experiments using maize (Zea mays) to investigate the effects of varying Cd concentrations (0, 0.5, 1.0, 2.5, and 5.0 mg/kg) on phosphorus uptake, soil phosphorus fractions, and microbial diversity. The results revealed that when soil Cd concentrations exceeded 1.0 mg/kg, maize growth and phosphorus uptake were significantly inhibited (P < 0.05), with a 25.3-64.9% reduction in yield. Cd pollution decreased soil available phosphorus and altered its chemical forms, as indicated by a decrease in soluble P fractions (H2O-Pi, NaHCO3-Pi) and an increase in insoluble P fractions (NaOH-Pi, HCl-Pi). Total organic and inorganic phosphorus increased by 5.6-29.4% and 5.8-23.5%, respectively, while active phosphorus decreased by 19.3-58.6%, and steady-state phosphorus increased by 5.2-26.0%. The activities of alkaline phosphatase (AKP) and acid phosphatase (ACP) were significantly reduced under higher Cd concentrations (P < 0.05). Microbial biomass carbon (MBC) decreased significantly, while phosphorus transformation-related genes (phoD, phnK, ppx, pqqC) were reduced by up to 82.4%. In summary, Cd pollution significantly alters maize rhizosphere microbial communities, reduces the abundance of phosphorus transformation-related microorganisms and functional genes, and disputes phosphorus mineralization. These changes reduced soil active phosphorus content, ultimately decreasing phosphorus availability for maize. This study emphasizes the need for further research on Cd-induced phosphorus transformation mechanisms and microbial responses, and suggests developing soil management strategies to mitigate the adverse effects of Cd on phosphorus availability.

Quantifying intraspecific variation in host resistance and tolerance to a lethal pathogen

Testing for intraspecific variation for host tolerance or resistance in wild populations is important for informing conservation decisions about captive breeding, translocation, and disease treatment. Here, we test the importance of tolerance and resistance in multiple populations of boreal toads (Anaxyrus boreas boreas) against Batrachochytrium dendrobatidis (Bd), the amphibian fungal pathogen responsible for the greatest host biodiversity loss due to disease. Boreal toads have severely declined in Colorado (CO) due to Bd, but toad populations challenged with Bd in western Wyoming (WY) appear to be less affected. We used a common garden infection experiment to expose post-metamorphic toads sourced from four populations (2 in CO and 2 in WY) to Bd and monitored changes in mass, pathogen burden and survival for 8 weeks. We used a multi-state modelling approach to estimate weekly survival and transition probabilities between infected and cleared states, reflecting a dynamic infection process that traditional approaches fail to capture. We found that WY boreal toads are more tolerant to Bd infection with higher survival probabilities than those in CO when infected with identical pathogen burdens. WY toads also appeared more resistant to Bd with a higher probability of infection clearance and an average of 5 days longer to reach peak infection burdens. Our results demonstrate strong intraspecific differences in tolerance and resistance that likely contribute to why population declines vary regionally across this species. Our multi-state framework allowed us to gain inference on typically hidden disease processes when testing for host tolerance or resistance. Our findings demonstrate that describing an entire host species as 'tolerant' or 'resistant' (or lack thereof) is unwise without testing for intraspecific variation.

The Erosion of Threatened Southern Mountain Caribou Migration

Migration enables animals to access seasonally and spatially varying resources, resulting in greater abundance compared to analogous non-migratory wildlife. Both Western science and Indigenous knowledge recognize the critical role of migration in sustaining wildlife; yet these movements are increasingly disrupted by human activity worldwide. Despite their importance, long-term changes in migratory patterns for large mammals remain challenging to quantify. Therefore, to address this gap, we analyzed 35 years (1987-2022) of telemetry data for southern mountain caribou (n = 2967 animal-years), a threatened population that typically exhibits two main types of annual migration. The first type is a single horizontal migration between summer and winter ranges, while the second is a twice-per-year vertical migration between high and low elevations. We studied the extent and type of migration, changes through time, and determined if these changes correlated with landscape disturbance or shifts in weather. Our results show that caribou reduced their migratory duration (2-3 days/decade), distance (6-8 km/decade or 15%-25%) and elevation change (120-150 m/decade or 7%-23% for elevational migrants). The subpopulations of caribou adapted to extreme snow depths conducted a unique elevational migration twice a year, which is globally distinctive among ungulates. However, this elevational migration is diminishing in distance and elevation. The changes in elevational and horizontal migration correlated with increased human disturbance, especially of low-elevation winter ranges. Changes in weather did not appear to be a major driver of the migratory declines. Declines in migratory behaviour occurred concomitantly with population declines and increases in disturbance, and these processes are likely intertwined. The rapid loss of these unique migrations is a significant conservation concern that could have irreversible consequences for the social transmission of fitness-maximizing behaviors.

Duration of O2 Exposure Determines Dominance of FeII vs CH4 Production in Tropical Forest Soils

Temporal fluctuations in redox conditions influence the availability of FeIII and greenhouse gas emissions in humid upland soils. However, the impact of fluctuation duration on biogeochemical processes remains unclear. We hypothesized that rates of FeIII reduction and CH4 production are sensitive to the duration of soil oxygenation. To test this, surface soil from the Luquillo Forest, Puerto Rico, was subjected to fluctuating redox conditions with an anoxic interval of 6 days followed by oxic intervals of either 8, 24, or 72 h. Shorter oxic intervals enhanced Fe reduction, while longer oxic intervals enhanced CH4 emissions. As O2 exposure decreased from 72 to 8 h, Fe reduction rates increased from 0.12 ± 0.02 to 0.26 ± 0.05 mmol kg-1 h-1, whereas cumulative CH4 decreased from 44.0 ± 4.7 to 12.7 ± 4.6 μmol kg-1. 13C-amino acid spikes were preferentially incorporated into the DNA of iron reducers (Anaeromyxobacter sp.) in the shorter oxic treatment (8 h vs 24 h), suggesting that Fe reducers are less inhibited by shorter periods of oxidation. Conversely, longer oxygen pulses appear to suppress Fe reducers more than methanogens, leading to increased CH4 emissions. These findings highlight the role of the redox oscillation length in modulating biogeochemical processes and greenhouse gas emissions in soils.

Assessing trends and density of bird species in bottomland hardwood forests and riparian forests using simulation and sample size optimization for surveys

The decline of neotropical migratory birds in North America is closely tied to habitat loss, including the degradation of bottomland hardwood and riparian forests, which provide essential habitats for numerous species. To address this, the U.S. Fish and Wildlife Service conducts bird surveys to monitor restoration efforts and evaluate conservation outcomes. This study assessed avian surveys from three National Wildlife Refuges in Texas and Oklahoma, using simulations, field data, and literature to evaluate current sampling protocols. Our findings revealed that achieving acceptable precision in bird density estimates (coefficient of variation: 0.15, 0.25) often requires more than 200 bird point counts, depending on the species and study area. While data aggregation across sites and years improved precision, it masked local trends critical for refuge-specific management. Imprecise results, particularly for rare species, underscored the need for improved protocols, such as repeat visits within a year, targeted sampling for priority species, and adaptive designs incorporating forest composition and structure data. These adjustments would enhance the precision of multispecies surveys, making them more effective for detecting changes in habitat quality. This study provides actionable recommendations to support service-wide efforts in strategic, data-driven monitoring and long-term conservation planning for neotropical migratory birds.

Ecological and evolutionary drivers of stingless bee honey variation at the global scale

Stingless bee honey (SBH) is a prime natural product consumed and used for diverse medicinal and traditional purposes by local communities across the (sub-)tropics. Despite its ecological and cultural significance, the drivers of its compositional variation within and among species remain poorly understood, particularly throughout Asia and sub-Saharan Africa. Addressing this issue at the global scale has the potential to inform broader and less explored eco-evolutionary and how variation in SBH across the (sub-)tropics has led human communities to develop diverse and sometimes specific patterns of practices that are now integral to their cultural and economic life. In this study, we aimed to disentangle the roles of evolutionary and environmental drivers of SBH compositional variation using a sampling design that combines honey profiling by H1-NMR spectroscopy with the collection of honeys from honey bees and stingless bees at the global scale. The results show a clear differentiation between the chemical composition and functional diversity of honey bee and stingless bee honeys, mainly due to the production of a range of bioproducts during sugar fermentation. The study of compositional variation of stingless bee honey showed that the role of ecological and evolutionary drivers and their joint effects varied within each tropical region, preventing the identification of a clear continental, phylogenetic or ecological pattern. We provide the first global and comprehensive characterization of SBH composition, a prerequisite for defining and accepting SBH in the different Codex Alimentarius. We also highlight the need for more interdisciplinary and trans-sectoral research adopting a holistic approach to investigate stingless bee honey characteristics.

Shifting, expanding, or contracting? Range movement consequences for biodiversity

Climate change is causing species ranges to shift, expand, and contract, with divergent and underappreciated consequences for local and global biodiversity. Widespread range shifts should increase local diversity in most areas but reduce it in the tropical lowlands. Widespread expansions should maintain diversity at low latitudes while increasing diversity elsewhere, leading to stable global biodiversity. Expansions and shifts are both common responses to climate change now and in the deep past. To understand how changing ranges will reshape Earth's biodiversity, we argue for three research directions: (i) leverage paleontological data to reveal long-term biodiversity responses, (ii) better monitor low-elevation and latitude limits to distinguish shifts from expansions, and (iii) incorporate dispersal barriers that can turn would-be shifts into contractions and extinctions.

Towards transient space-use dynamics: re-envisioning models of utilization distribution and their applications

BACKGROUND

Models of utilization distribution in the form of partial differential equations have long contributed to our understanding of organismal space use patterns. In studies of infectious diseases, they are also being increasingly adopted in support of epidemic forecasting and scenario planning. However, as movement research shifts its focus towards large data collection and statistical modeling of movement trajectories, the development of such models has notably slowed.

METHODS

Here, we demonstrate the continued importance of modeling utilization distribution to predict variation in space-use patterns over time. We highlight the considerable, yet largely untapped, potential of such models, which have historically been limited by the steady-state assumption due to longstanding technical constraints. Now, by adapting existing computational tools primarily developed for material science and engineering, we can probe beyond the steady states and unlock from them a broad spectrum of complex, transient space-use dynamics. Our approach requires little experience in numerical analysis and is readily accessible to model practitioners in ecology and epidemiology across diverse systems where movement is a critical feature.

RESULTS

We illustrated our approach using a mix of canonical and novel case studies, covering topics from wildlife translocation to vaccine deployment. First, we revisited a classical model of canid territorial formation driven by scent-mediated conspecific avoidance. Transient space-use analysis uncovered previously hidden spatial dynamics that are ecologically informative. Next, we applied our approach to long-distance movement on realistic landscapes. Habitat and land-use heterogeneities markedly affected the transient space-use dynamics and short-term forecasts, even when the steady state remained unchanged, with direct implications for conservation management. Finally, we modeled transient space-use dynamics as both a response to and a driver of transient population dynamics. The importance of this interdependence was shown in the context of epidemiology, in a scenario where the movement of healthcare personnel is influenced by local outbreak conditions that are stochastically evolving.

CONCLUSIONS

By facilitating transient space-use analysis, our approach could lead to reevaluations of foundational ecological concepts such as home range and territory, replacing static with dynamic definitions that more accurately reflect biological realities. Furthermore, we contend that a growing interest in transient space-use dynamics, spurred by this work, could have transformative effects, stimulating new research avenues in ecology and epidemiology.

Perspectives on mating-system evolution: comparing concepts in plants and animals

The study of mating systems, defined as the distribution of who mates with whom and how often in a sexually reproducing population, forms a core pillar of evolution research due to their effects on many evolutionary phenomena. Historically, the "mating system" has either been used to refer to the rate of self-fertilization or to the formation of mating pairs between individuals of distinct sexes. Consequently, these two types of mating systems have tended to be studied separately rather than jointly. This separation often means that mating systems are not necessarily researched in a coherent manner that might apply to different types of organisms (e.g., plants versus animals, or hermaphrodites versus dioecious species), even if similar mechanisms may drive the evolution of self-fertilization and mating pair formation. Here, we review the evolution of both plant and animal mating systems, highlighting where similar concepts underlie both these fields and also where differing mechanisms are at play. We particularly focus on the effects of inbreeding, but also discuss the influence of spatial dynamics on mating-system evolution. We end with a synthesis of these different ideas and propose ideas for which concepts can be considered together to move towards a more cohesive approach to studying mating-system evolution.

Fish by-products as reliable proxies to evaluate nutritional fatty acid contents in commercial fish fillets

Despite seafood being the primary source of long-chain omega-3 polyunsaturated fatty acids (PUFAs), the fatty acid (FA) contents of numerous exploited fish species remain unknown, partly due to the prohibitive costs associated with sourcing commercial fish fillets. We assessed whether fish by-products can reliably be used to estimate key nutritional FA contents in fillets by testing for consistent relationships between FA contents in fillet, and those in the breast, cheek, occiput, and tail tissue of three commercial coral reef fish species. Breast tissue was most suitable for estimating concentrations and proportions of FAs in the fillet due to strong and consistent relationships across FA types and species. In contrast, relationships between FA contents in the fillet and in other by-products were inconsistent across species and/or FA types. Through reducing research costs and food waste, utilising by-products will encourage FA research, particularly in tropical regions where omega-3 deficiency rates are highest.

Trophic niche dynamics of two fish mesoconsumers in adjacent coastal habitats with varying nutrient regimes

Changes of consumers' trophic niches, the n-dimensional biotic space that allows a species to satisfy its minimum requirements for population growth, are driven in part by shifts in the degree of individual resource use specialization within a population. Individual specialization results from complex trade-offs in inter- and intraspecific competition as organisms reduce niche overlap within a population or with heterospecifics. It is vital to build empirical knowledge on the trophic niche dynamics of consumers, given the role that niche dynamics play in food web stability, species coexistence, and population resilience, especially quantifying the trophic niche's expansion and contraction of coastal fish populations experiencing increasing frequency of environmental disturbance and habitat transformation. In coastal ecosystems, disturbances alter the connectivity, productivity, and nutrient regimes of aquatic habitats, which could lead to significant shifts in consumers' trophic niches. We investigated the trophic niche dynamics of two fish species Centropomus undecimalis (Common Snook) and Megalops atlanticus (Atlantic Tarpon), across two adjacent coastal lake systems of varying nutrient regimes (eutrophic vs. mesotrophic) and hydrological connectivity. In both systems, Snook had larger trophic niches than Tarpon. Also, the trophic niche size in the eutrophic system was larger than the mesotrophic system for both species. Snook and Tarpon used different prey resources, resulting in low niche overlap between species in both systems. Our results highlight how altered hydrological connectivity, and nutrient regimes can shift trophic niche dynamics of higher trophic-level consumers, likely due to changes in prey landscapes and shifts in the foraging ecology of species.

Pinyon Jays (Gymnorhinus cyanocephalus) and Clark's nutcrackers (Nucifraga columbiana) can discriminate between pilfering and non-pilfering conspecifics, but not between heterospecifics

When foraging, individuals often need to assess potential risk from competitors. Within many food-caching (food-storing) species, individuals can modify their caching behavior depending on whether other individuals are present during the caching event. During caching, individuals may interact with not only conspecifics but also heterospecifics. However, the extent to which individual cachers can discriminate between conspecifics and heterospecifics that present a pilfering threat or not, has received little attention. During this study, we examined this issue with food-storing birds, highly social pinyon jays and less social Clark's nutcrackers. Cachers were given a choice to store their seeds in one of two visually distinct trays. Subsequently, one of the trays was given to an individual (either a conspecific or a heterospecific) who pilfered the caches, whereas the other tray was given to an individual (either a conspecific or a heterospecific) who did not pilfer the caches. When the two trays were returned to the cachers, they recached the seeds from the tray given to the pilfering observer individual more so than the tray given to the non-pilfering observer, but only when the pilferer was a conspecific. Our results suggest that the pinyon jays and nutcrackers could distinguish between conspecifics based on their pilfering behavior, but not between heterospecifics. Together, our results reconsider the ability of corvids to discriminate between individuals based on their pilfering risk and the importance of doing so while caching.

Morpho-physiological traits of soybean plants in symbiosis with Gigaspora sp. and submitted to water restriction

In agricultural production, periods in which there is a lack of water can affect the productivity of soybean crops. One alternative is the use of arbuscular mycorrhizal fungi (AMF), which maximize water absorption, biochemical regulation, leaf elasticity and transpiration, and water use regulation. The present study aimed to analyze the morphological and physiological traits of soybean plants associated with Gigaspora margarita and Gigaspora gigantea submitted to water restriction in nonsterilized soil. The soybean plants received 31 g of the AMF Gigaspora margarita or 46 g of Gigaspora gigantea separately at sowing and were cultivated in a greenhouse under natural light conditions with controlled relative humidity and temperature. Water restriction was imposed when the plants reached the V3 stage and were divided into three levels: irrigated (80%), moderate (60%), and severe (40%) field capacity (FC). The experimental design was completely randomized in a 3 × 3 factorial design (three inoculation treatments × three water restriction levels). Physiological and morphological parameters, photosynthetic pigments, electrolyte leakage, root colonization of soybean plants, and percentage of fungal spores were evaluated. The inoculation of Gigaspora gigantea promoted the adaptation of physiological (photosynthesis rate, transpiration, stomatal conductance, Ci/Ca ratio, and carboxylation) and morphological traits (plant height and stem diameter), with greater colonization of soybean roots under conditions of water restriction, and maximized the tolerance of plants to drought, mitigating the negative effects of these conditions regardless of the level of water restriction. Mycorrhizal inoculation promoted better functioning of the photosynthetic apparatus and growth of soybean plants.

Multi-modal Language models in bioacoustics with zero-shot transfer: a case study

Automatically detecting sound events with Artificial Intelligence (AI) has become increas- ingly popular in the field of bioacoustics, ecoacoustics, and soundscape ecology, particularly for wildlife monitoring and conservation. Conventional methods predominantly employ supervised learning techniques that depend on substantial amounts of manually annotated bioacoustic data. However, manual annotation in bioacoustics is tremendously resource- intensive in terms of both human labor and financial resources, and it requires considerable domain expertise. Moreover, the supervised learning framework limits the application scope to predefined categories within a closed setting. The recent advent of Multi-Modal Language Models has markedly enhanced the versatility and possibilities within the realm of AI appli- cations, as this technique addresses many of the challenges that inhibit the deployment of AI in real-world applications. In this paper, we explore the potential of Multi-Modal Language Models in the context of bioacoustics through a case study. We aim to showcase the potential and limitations of Multi-Modal Language Models in bioacoustic applications. In our case study, we applied an Audio-Language Model--a type of Multi-Modal Language Model that aligns language with audio / sound recording data--named CLAP (Contrastive Language-Audio Pretraining) to eight bioacoustic benchmarks covering a wide variety of sounds previously unfamiliar to the model. We demonstrate that CLAP, after simple prompt engineering, can effectively recognize group-level categories such as birds, frogs, and whales across the benchmarks without the need for specific model fine-tuning or additional training, achieving a zero-shot transfer recognition performance comparable to supervised learning baselines. Moreover, we show that CLAP has the potential to perform tasks previously unattainable with supervised bioacoustic approaches, such as estimating relative distances and discovering unknown animal species. On the other hand, we also identify limitations of CLAP, such as the model's inability to recognize fine-grained species-level categories and the reliance on manually engineered text prompts in real-world applications.