Ecology

Plant communities within a metacommunity can vary widely in their degree of invasion by introduced species. Disturbance, propagule pressure, and biotic resistance are common explanations for this variation, but empirical evidence for these hypotheses is mixed. Alternatively, the community assembly framework predicts that local assembly filters determine both native and exotic composition, but lower trait variation in the introduced species pool may exclude them from certain sites. We examined evidence for this framework using observational data from forests and woodlands of Long Island, NY, USA. These forests vary in vegetation composition and invasion along a soil gradient. They are also highly disturbed and fragmented, yet some stands have almost no introduced plants. Using data collected in 1998 and 2021-22, we quantified relationships between community composition, soil characteristics, and functional traits for native and exotic assemblages, as indicators of environmental filtering. We found similar trait-environment relationships in native and introduced species, suggesting that both groups follow the same local assembly rules. Introduced species were predominantly found in sites with more nutrient-rich soils and were absent from sites with nutrient-poor soils. At the regional scale, the exotic species pool was biased toward trait values favored in more nutrient-rich environments, particularly high growth rates and low leaf C:N ratios, which explains their absence from nutrient-poor environments. These patterns were consistent over time, and stands that were uninvaded in 1998 remained so in 2021-22, supporting the robustness and reliability of short-term studies. This study shows that invasion patterns in plant communities can be explained by the assembly rules that govern native species. By linking local environmental filtering with regional species pool characteristics, this work advances our understanding of how some communities remain uninvaded despite high disturbance and propagule pressure. Overall, these results highlight the utility of the community assembly framework, and emphasize the importance of regional processes in constraining the local distribution of introduced species.

O_LIStage-dependent interactions, in which different life cycle stages (e.g., juveniles, adults) exert different per-capita competitive effects, are widespread across ecological communities. However, whether explicitly accounting for such ontogenetic variation improves forecasts of stochastic community dynamics remains unclear. We tested how the strength of stage dependence and species life-history strategy influence the predictive accuracy of community models that either include or ignore stage-specific interactions. C_LIO_LIWe constructed stochastic two-species competition models using stage-structured matrix population models spanning five virtual life histories along the fast-slow continuum. Density dependence was imposed separately on juvenile survival, adult survival, progression, retrogression, or fertility, and the strength of stage dependence varied from adult-driven to juvenile-driven competition. We then fitted deterministic projection models with and without stage-dependent interaction terms to simulated time series and quantified predictive performance over 100 time-step forecasts using mean absolute percentage error (MAPE). C_LIO_LIIncreasing stage dependence consistently reduced the predictive accuracy of models that ignored stage structure. However, absolute prediction errors remained small across all scenarios (MAPE < 0.7%), even under strong stage dependence. The influence of life-history strategy depended on which vital rate was density dependent: when juvenile survival was density dependent, faster life histories showed larger errors; when progression, retrogression, or fertility were density dependent, slower life histories exhibited greater errors; and when adult survival was density dependent, no consistent life-history effect emerged. Across simulations, temporal variation in population structure was low (coefficient of variation < 0.036), and prediction error was strongly associated with the magnitude of structural fluctuations rather than life-history pace per se. C_LIO_LISynthesis. Stage-dependent interactions can, in principle, alter stochastic competitive dynamics, but their practical importance for ecological forecasting depends on the extent to which population stage structure fluctuates through time. When environmental stochasticity dominates and stage structure remains near equilibrium, simpler models that ignore stage dependence provide robust approximations of community dynamics. Our results identify conditions under which demographic detail is necessary for forecasting and highlight the central role of structural variability in linking life-history strategy to community-level dynamics. C_LI

Predation is a strong environmental and selective pressure that can favour rapid and plastic shifts in behaviour and escape ability to increase an organisms immediate survival. However, maintaining antipredator responses under repeated predation stress can induce physiological costs to an organism from long-term exposure to elevated cortisol. We know little about how individuals balance this trade-off between short-term survival and longevity, including whether males and females balance this trade-off differently based on life history differences in reproduction, survival, and risk adversity. To assess sex differences in long-term behavioural responses and physiological costs to predation risk, we exposed threespine stickleback (Gasterosteus aculeatus) to visual cues of a live rainbow trout (Oncorhynchus mykiss) predator twice a week for 14 weeks, then measured stickleback antipredator behaviour and swimming performance 5 months later. To quantify potential long-term costs of behavioural adaptation, we measured relative telomere length as a proxy for long-term oxidative damage. We found strong sex specific effects in behaviour and swim endurance: males, but not females, altered their hiding behaviour and had shorter swim endurance in the first trial, suggesting overall lower activity. Surprisingly, we found no evidence for chronic predation shortening telomere length or hindering growth in body length. Overall, these results suggest that plastic responses can be dictated by the different life-history strategies for males and females, and suggest that individuals can maintain long-term changes in antipredator behaviour without costs to their physiological state. HighlightsO_LIChronic predator exposure produced persistent sex differences in space use and swim performance. C_LIO_LIPredator-exposed males altered their hiding strategy and showed reduced swim performance, while females showed no behavioural or performance differences. C_LIO_LIDifferences in swim times were restricted to the first trial and all individuals were exhausted by trial 3. C_LIO_LIRelative telomere length and growth in length did not differ between exposed and unexposed individuals. C_LI

O_LIAbundance of insect herbivores often depends on host plant suitability for their specialised immature stages. Suitability can be strongly influenced by both microclimate and the nutritional quality of the plants themselves. Where soil nitrogen is high, host plants tend to have high nutritional quality, but vigorous growth of surrounding vegetation reduces microclimatic temperatures. Thus, thermophilous insects may face a choice between host plants with optimal microclimates and those with optimal nutritional quality. C_LIO_LIWe investigated how microclimate and nitrogen content influence oviposition choices by the declining Small Copper butterfly, Lycaena phlaeas, on its host plant, Rumex acetosa. We predicted that warmer plants would have lower nitrogen content, and that butterflies would choose cooler, high-nitrogen plants during warmer ambient conditions. C_LIO_LIAlthough warmer R. acetosa plants had lower nitrogen content, L. phlaeas consistently chose to lay eggs on plants in warm microclimates, implying a trade-off between temperature and the nutritional quality of host plants. C_LIO_LIPatches of bare ground created by Talpa europaea (European Mole) near R. acetosa plants increased microclimatic temperatures and decoupled the negative correlation between nutritional quality and thermal suitability. C_LIO_LIOur results have implications for the conservation of thermophilous insect herbivores, especially close to their range margins and in the context of climate change. Rather than maximising host plant abundance or nutritional quality, management that creates suitable microclimatic conditions is likely to be critical. Our findings also suggest that, while nitrogen pollution may increase host plant nutritional quality, its negative impacts on microclimate will likely further reduce breeding habitat for L. phlaeas and other insects in grassland habitats. C_LI

Reduced competition or facilitation between kin relative to nonkin can improve plant performance, particularly under resource-limited conditions. Understanding whether kin interactions differ between invasive and native species may provide insights into the mechanisms underlying the persistence and spread of invasive species, particularly for species that spread clonally. To explore this, we conducted a greenhouse experiment using the invasive Alternanthera philoxeroides and its native congener A. sessilis in China. For both species, we grew central plants without or with neighbors, and for the latter we had three intraspecific neighbor kinship treatments (kin only, nonkin only, and both kin and nonkin [mixed] neighbors). To test whether kinship effects are affected by resource limitation, we grew the plants under two watering conditions (well-watered and drought-stressed). Our findings revealed that at both the group (i.e., pot-level) and individual levels, invasive plants had a higher biomass production and experienced a less negative relative neighbor effect in kin groups than in nonkin groups, while these patterns were reversed in the native species. Although aboveground architecture of central plants did not differ significantly between kin and nonkin neighbors in either species, neighbor plants of the invasive species produced fewer nodes in kin groups than in nonkin groups, while the reverse was true for the native species. These patterns were not affected by the watering treatment. Together, these results indicate that while the native plants has stronger kin competition, the invasive species has reduced kin competition. Such reduced competition among kin in the invasive Alternanthera philoxeroides may enhance its population dominance and facilitate its spread.

O_LINitrogen (N) is limiting for terrestrial herbivores, particularly over winter. Caribou (Rangifer tarandus) have adapted to seasonal scarcity of N by accruing muscle mass during the growing season when N is more abundant. C_LIO_LINitrogen stored in muscle tissue is then relied upon during winter to compensate for dietary deficits. Once their diet shifts from N-rich vascular plants to N-poor lichen over winter, caribou can lose [~]30% of their muscle mass. As catabolized N is shed in urine on wintering grounds, caribou could act as elemental transport across seasons and landscapes. Furthermore, if deposited N is taken up by lichen or other winter forage, it might enrich the nitrogen-poor winter diet of caribou in the future. C_LIO_LIWe tested this potential transport via three steps. We analysed Cladonia spp. lichen and vascular plants upon which caribou forage across Fogo Island, Newfoundland, using %N content as our metric of forage quality. We then compared seasonal habitat selection responses to forage quality by caribou using integrated step selection analyses. In summer, caribou selected areas with higher vascular plant %N but did not select nor avoid Cladonia quality. In contrast, caribou selected sites with higher quality Cladonia in winter but responded neutrally to vascular plant quality. C_LIO_LIWe compared seasonal distributions of caribou to determine whether nitrogen consumed in summer and deposited in winter would occur in spatially discrete locations. Population-level kernel density estimates for summer and winter in this island herd were mostly non-overlapping, lending credence to the potential landscape effects of N transport. C_LIO_LIWhen viewed together with established seasonal changes in woodland caribou physiology, sociality, and forage preferences, the shifts in habitat selection and seasonal ranges we observe here could serve as an adaptive strategy for caribou to recycle N and mitigate winter nutrient scarcity. C_LI

Resource competition and parasite exposure both present common density-dependent fitness costs for wild animals. Because launching effective immune responses is costly in terms of resources, parasites fitness costs should be further exacerbated in high-density, resource-depleted areas. To disentangle these relationships, we related density, parasitism, and resource availability to survival and fecundity across lifespan in a long-term study of wild red deer. All fitness measures declined with a combination of parasite count, greater density, and reduced resource availability. Beyond these relationships, as expected, local density and resource scarcity exacerbated survival costs of parasitism in calves, effectively undermining tolerance of infection. However, these synergistic relationships faded in yearlings and then reversed in adults, likely through age-structured selection biases. These findings emphasize that the costs of parasites and resource scarcity can be synergistic and intertwined with density in wild populations, accentuating the value of incorporating resource competition when examining parasite-dependent population regulation.

O_LIPredicting coexistence in species-rich plant communities requires understanding the role of functional traits in species interactions and their resilience to environmental variation. C_LIO_LIIn a manipulative factorial field experiment in an annual community (>45,000 individuals and 45 species), we followed plant associations from seedling to adult on both preserved and altered biological soil crust over two years with contrasting weather conditions. Neighborhood models quantified how among-species differences in key functional traits affected coexistence and how these effects varied in response to ontogenetic stage, environmental variation and spatial scale. C_LIO_LITrait-based models revealed a prevalent negative relationship between functional differences and species associations, but these relationships varied predictively with stage, environment and spatial scale. Functional dissimilarity in traits such as specific leaf area, seed mass, and reproductive-to-vegetative biomass ratio consistently mediated species segregation, especially during wet years and among seedlings, while biological soil crust disturbance altered trait-mediated associations differently at fine and coarse spatial scales. C_LIO_LITrait-mediated species associations shift predictably with environmental variation, suggesting that coexistence reflects a dynamic balance between environmental filtering and competitive interactions. This work provides novel experimental evidence of when, where, and which traits predict community assembly, which has implications for forecasting biodiversity responses to global environmental change. C_LI

Anthropogenic climate change is expected to increase not only mean temperatures but also the magnitude and pattern of thermal variability, including the frequency, duration, and predictability of extreme events. While the effects of elevated mean temperatures on disease dynamics are well studied, far less is known about how different patterns of temperature variability shape host-parasite interactions, despite clear theoretical predictions from the climate variability hypothesis. Here, we used a controlled experimental system (Daphnia magna and two microsporidian parasites, Ordospora colligata and Hamiltosporidium tvaerminnensis) to disentangle the effects of thermal variability structure from mean temperature. Across two experiments, we exposed hosts to cyclic (predictable) and random (unpredictable) heatwaves under both non-stressful and stressful mean temperature regimes. Contrary to predictions from the climate variability hypothesis, temperature variability did not uniformly increase infection risk. Instead, infection outcomes depended on the interaction between mean temperature, duration of the heatwaves, the pattern of thermal variation, and parasite identity. Under non-stressful mean temperatures, thermal variability had negligible effects on infection. In contrast, under stressful mean temperatures, parasites responded in distinct ways: H. tvaerminnensis infection was sensitive to the predictability of heat events, whereas O. colligata responded primarily to heatwave duration. These results demonstrate that climatic variability can differentially alter host-parasite interactions rather than exerting consistent directional effects on disease. By showing that parasite-specific sensitivities to the pattern of thermal variation emerge under thermal stress, our study highlights a mechanism by which increasing climatic variability may reshape parasite communities and disease outcomes in a warming world.

Spatial heterogeneity of abiotic resources is essential for species coexistence. Ecological theory often assumes predefined heterogeneity of resources that constrains community dynamics, but the recent developments of meta-ecosystem ecology and zoogeochemistry highlight nutrient patterns could result from the interactions between the activities and movements of organisms and their abiotic environment. Here we investigate the mechanisms by which biotic-abiotic feedbacks could generate nutrient spatial heterogeneity in a simple plant-herbivore occupancy model where populations forage, recycle, and disperse in a homogenous landscape. By systematically varying organisms ranges of foraging and dispersal, and recycling levels, we found that limited dispersal of plants plays a key role on the emergence of nutrient patchiness by favoring small clusters of vegetation that shape their environment through consumption and recycling. However, herbivores could also create nutrient spatial heterogeneity when large foraging and dispersal ranges, and high recycling, allow them to efficiently track plant hot spots and to increase population persistence. Unexpectedly, strong aggregation of herbivore populations did not necessarily result in nutrient clustering. Rather than via recycling, herbivores mainly affected nutrient distribution indirectly, through their top-down impact on plant distribution. When evenly spread in the landscape, herbivore populations with large foraging ranges created areas of strong herbivory pressure unfavorable to plant colonization where nutrient can accumulate. These results can help understand the dynamical feedback between biota and abiotic resources. In a context where human activities alter both nutrient distribution and species abundances, a better understanding of this biotic-abiotic feedback will be key to anticipate the response of ecosystems to current perturbations.

Temperature fluctuations across space and time create a multidimensional thermal landscape within which organisms are exposed to local climates while conducting their daily activities. Tropical species are considered to be particularly sensitive to climate change, with narrow thermal safety margins - the buffer between operative and lethal temperatures. In tropical rainforests, however, species can hypothetically mediate thermal exposure via activity over two local thermal dimensions: vertical (ground-canopy) and temporal (day-night). Such spatiotemporal flexibility could protect species from elevated temperatures and improve thermal safety margins, but this mechanism has not been previously investigated. We test this hypothesis using rainforest ants at a warm lowland and cool upland site (100, 1200 m a.s.l.) in the Australian Wet Tropics. At lowland and upland sites, we quantified microclimate, foraging activity, community composition, and thermal ecology of ants across vertical and temporal dimensions. To assess spatiotemporal flexibility as a climate change mitigation strategy, we calculated thermal safety margins (TSM) as the difference between a species upper thermal limit (CTmax) and mean activity temperature (Te). For each species in each of their spatiotemporal niches (ground-arboreal-day-night) we test whether shifting activity to cooler niches increases TSM using the hottest niches (arboreal and/or daytime) as a baseline. At both lowland and upland sites, ant species were highly stratified vertically, but the large majority (77 - 87.5%) were active both day and night, indicating widespread temporal generalisation. Shifting activity to cooler parts of the thermal landscape substantially improved TSMs: in the lowlands, species with arboreal diurnal foraging increased their TSM by an average of 4.4 {degrees}C ({+/-} 1.7 SE) by shifting to the ground and 6.7 {degrees}C ({+/-} 1.63 SE) by shifting to nocturnal foraging. Improvements were more modest in the uplands: arboreal diurnal foragers increased TSM by 2.1 {degrees}C ({+/-} 2.07 SE) and 2 {degrees}C ({+/-} 0.28 SE) for ground and nocturnal shifts respectively. We therefore demonstrate that foraging niche flexibility is an important climate-change mitigation trait and is most beneficial in the lowlands. Lowland diurnal canopy specialists, however, are most at risk. This represents a large proportion of tropical rainforest biodiversity, supporting previous hypotheses of lowland biotic attrition under climate change.

Habitat structure, food availability, and predation risk have spatiotemporal variation on the landscape that creates tradeoffs between risk and rewards for animals as they use habitat. These tradeoffs are associated with survival consequences and can vary by life or breeding stage, but stage-specific shifts in these relationships are often not considered in studies of habitat use and survival. We investigated habitat use for nests and broods in the Mountain plover as an exemplar of a ground-nesting species with precocial, mobile young to explore site- and breeding stage-specific responses to vegetation structure, food availability, and predation risk. We located and monitored nests and broods at two study sites in Colorado occupied by geographically separated breeding populations of plovers. We quantified the three covariate categories across standardized site-wide grids in 2021 and 2022. We employed a resource selection analysis to evaluate 10 a priori working hypotheses for how environmental covariates may influence the habitat used by plovers for nesting and brood-rearing. Model comparison results suggest that habitat use relative to availability is best explained by a quadratic relationship with vegetation structure dependent on breeding stage and site but not influenced by food availability or predation risk. Specifically, probability of use for nest sites was highest in areas with shorter vegetation, consistent with previous research, while probability of use for broods was lowest in areas with moderate groundcover height and bare ground coverage and highest at the extremes. These results emphasize the importance of investigating stage-specific habitat use for species with precocial young.

Parasite prevalence varies in time and space. Thus, hosts may escape infection by dispersing out of habitats where parasites are present. However, it is not clear if the advantage of avoiding parasites outweighs the cost of dispersing. Juvenile hosts are expected to be relatively protected from environmentally-transmitted parasites, and we hypothesize that this age bias in transmission could magnify the benefits of juvenile (i.e., natal) dispersal. We tested these ideas in the model nematode Caenorhabditis elegans, a host with discrete life stages and natal dispersal, and its environmentally transmitted microsporidian parasite Nematocida parisii. We found that under standardized exposure conditions, larger C. elegans individuals (corresponding to older life stages) acquired many more parasites than smaller (younger) individuals. We found this same bias during multigeneration epidemics, especially during early stages of the epidemics. We also found that C. elegans dispersal larvae were less likely to be infected and harbored less severe infections than the population mean. We conclude that the early stages of an epidemic can provide young hosts with a window of opportunity to escape infection by dispersing.

O_LISpecies diversity potentially has a dual effect on communities: a generally positive effect on overall community biomass, reflecting the expression of species response and interaction traits, and a poorly characterised effect on mass-specific species contribution to ecosystem functions, reflecting the expression of their effect traits. Disentangling the effects of biodiversity on total biomass from those on effect trait expression would help settle a long-standing debate by clarifying how biodiversity relates to both facets of species effects on ecosystem functioning. C_LIO_LIFollowing the classical BEF approach, we calculate expected ecosystem function based on observed functioning in monoculture. We then derive a net biodiversity effect (NBE) and decompose it into four components: the classical complementarity and selection effects on total community biomass, and complementarity and selection effects on effect trait expression. The latter two reflect, respectively, a complementarity or facilitation in how effect traits influence the function, and how species with the highest potential for increasing the function become dominant in the community. C_LIO_LIWe illustrate this NBE decomposition with three ecosystem functions (nitrogen retention capacity, soil hydraulic conductivity improvement, and forage digestibility) measured in assembled communities under controlled experimental conditions of perennial grassland plants. Regarding nitrogen retention, we find a positive complementary effect via total biomass, but a negative biodiversity effect via effect trait expression. For hydraulic conductivity improvement, biodiversity effects are mostly mediated by total biomass. As for forage digestibility, we found a positive complementarity effect on trait expression, outweighed however by a negative selection effect. This analysis reveals how biodiversity may have contrasting effects on ecosystem functions via its impact on biomass and effect trait expression. C_LI SynthesisSeparating between the effect of biodiversity on plant community biomass and on effect trait expression at the community level is one important step towards understanding the pathways by which diverse plant communities drive ecosystem functioning.

Substantial anthropogenic changes to the environment have motivated efforts to quantify temporal trends in population dynamics. While most ecological research has focused on the mean and variance of population density and reproduction, the frequency of these fluctuations through time may also be changing. We analyzed 1,563 datasets of population density and 1,456 datasets of plant reproduction (masting) across the globe. The average frequency of fluctuations increased by [~] 0.5 - 3% per decade within each time series, representing a moderate change (Cohens d {approx} 0.4) over a period of 60 years. We tested four hypothesized mediators of this trend: increased temperature, increased frequency of environmental forcing, increased intrinsic growth rate, and increased distance from a saddle at zero density. Although all hypotheses were rejected, changes in the frequency of environmental forcing and intrinsic growth rate exhibited positive correlations with changes in population fluctuation frequency as expected. Our results suggest that successive peaks in population and masting density fluctuations are becoming closer in time, which may reduce the effectiveness of predator satiation, resilience of food-webs, and the risk of critical transitions, such as population extinction. We suggest some alternative hypotheses for what may underlie this surprising global pattern.

Anthropogenic changes to the environment, including altered food resource availability, influence host physiology, behaviour, and population dynamics, which can have strong downstream consequences on wildlife disease dynamics. Additionally, some individuals within a population contribute disproportionately to infection as super-shedders of infection, but the extent to which food availability alters the likelihood of super-shedding and overall parasite infection patterns is poorly understood. We conducted a three-year field experiment in southern Finland to investigate how food supplementation and parasite removal affect nematode infection measures and the relationship between nematode infection and fitness of wild bank voles (Clethrionomys glareolus). Using a factorial design across 12 populations, we manipulated food availability and administered anthelmintic treatments to assess effects on nematode infection status, intensity, and two measures of super-shedding (abundance super-shedding, intensity super-shedding). We also examined parasite impacts on host fitness, including apparent survival probability and reproductive status. Food supplementation did not affect likelihood of infection, intensity or intensity super-shedding, but did reduce the likelihood of abundance super-shedding, suggesting an effect of food availability on infection heterogeneity. We also identified an interaction between nematode infection status and host age on fitness. Notably, infected younger individuals had reduced survival and reproduction, but infected older individuals had greater survival and reproduction compared to their uninfected counterparts. Our study provides novel empirical evidence on how anthropogenic changes in food availability can influence parasite transmission dynamics and the fitness consequences of these sub-lethal parasites in a wildlife system.

Emerging infectious diseases are a persistent public health threat that challenge deterministic, mechanistic modeling approaches. Because outbreaks initially start with a low number of infected hosts, their dynamics are highly stochastic, making traditional deterministic methods, e.g. ordinary differential equations, unable to qualitatively or quantitatively capture the transmission dynamics. In place, stochastic models are used, such as Markov chain models, but these models present their own challenges. Often, to infer a quantity of interest with stochastic models, we need to sample the models distribution many times over, introducing an additional source of noise to our analysis. This additional noise makes the inference of our quantity of interest more difficult and computationally expensive. Here, we show how novel tools from the field of uncertainty quantification can be used to efficiently separate these two channels of noise, allowing us to make rigorous statistical inferences about processes important for disease emergence. We illustrate these techniques with a model of yellow fever virus spillover in the Americas, a virus that has seen rapid re-emergence amongst multiple hosts and vectors in South America over the last decade. We show that only a handful of parameters uncertainties greatly affect variation in cumulative disease incidence. In particular, uncertainty in patch connectivity and non-human primate latency has the greatest impact on the variation of cumulative disease incidence of yellow fever virus across patches. Author ContributionsConceptualization: Nate Kornetzke, Helen J. Wearing. Methodology: Nate Kornetzke, Helen J. Wearing. Formal Analysis: Nate Kornetzke. Software: Nate Kornetzke. Visualization: Nate Kornetzke. Writing, Original Draft Preparation: Nate Kornetzke. Writing, Review and Editing: Helen J. Wearing. Supervision: Helen J. Wearing. Author SummaryEmerging infectious diseases are a growing threat to public health. Computational models allow researchers to forecast future disease burdens and to investigate counterfactual scenarios, and often, these models are stochastic, i.e. contain randomness, to capture the qualitative behavior of emergence. A type of statistical analysis known as global sensitivity analysis allows modelers to rigorously analyze how varying the input to a model affects variation in its outputs. This type of analysis helps us infer what mechanisms are important for disease mitigation and control, especially when an infectious disease has a complex ecology consisting of multiple hosts and vectors. Until recently, stochastic models of emerging infectious diseases often proved too computationally expensive to perform a global sensitivity analysis on. Here, we demonstrate how new mathematical tools allow us to streamline this process for complex models of emerging infectious diseases. We analyze the ecology of re-emerging yellow fever in South America, a public health threat occurring in many hosts and vectors across vastly different ecosystems.

Climate change is increasing the frequency of wildfires in ecosystems that historically rarely burn, such as wet heaths and peatlands, thereby threatening carbon storage, biodiversity, and ecosystem functioning. We conducted a three-year, multi-level study to assess early post-fire recovery trajectories of soil physicochemical properties, vegetation, and soil microbial communities in a wet peatland-heathland mosaic affected by a flaming wildfire. Using a paired-plot design of burned and adjacent intact plots, we observed immediate spikes in bioavailable nitrogen (NH, NO-) and phosphorus (POlsen) and a reduction in soil moisture in burned plots, yet two years later these parameters had normalized, indicating rapid abiotic recovery. Vegetation was also strongly altered in the year of the fire, quantifiable by a distinct destruction of herb, moss, tree and litter cover. Although initial regrowth was dominated by a relatively fast resprouting of the graminoid Molinia caerulea, its absolute cover in burned plots never exceeded its cover in intact plots, suggesting this species did not expand post-fire. More typical peatland and wet heath species, including ericoid shrubs and Sphagnum mosses, recovered more gradually but largely returned to pre-fire levels within the timespan of our study, highlighting high vegetation resilience. Soil microbial communities showed contrasting responses. Prokaryotic communities shifted immediately after burning but largely recovered within one year. Fungal communities, however, exhibited stronger and more persistent changes and followed a distinct recovery trajectory shaped by succession of immediate and delayed fungal responders. Overall, pyrophilous and fire-tolerant fungi, such as Coniochaeta spp., increased, as did many presumably generalist or opportunistic saprotrophs. Litter and wood-associated saprotrophs as well as many mycorrhizal taxa, however, declined. Ongoing fungal shifts occurred even after soil chemistry and vegetation had largely returned to baseline, reflecting a temporary decoupling between above- and belowground communities that may have cascading effects on ecosystem functioning. In conclusion, our results reveal differential recovery trajectories across the soil-microbiome-vegetation interface and highlight that seemingly rapid abiotic and aboveground biotic recovery can mask prolonged microbial disruptions. We emphasize the importance of multi-level assessments for understanding ecosystem resilience. HighlightsO_LISoil physicochemistry, vegetation and prokaryotes recovered rapidly after a peatland wildfire C_LIO_LIFungal communities lagged behind and followed a slower recovery trajectory C_LIO_LIThe timing and duration of fungal responses to fire varied across taxa and included immediate or delayed as well as short-lived or persistent responders C_LIO_LIThere was a mismatch between vegetation and fungal recovery trajectories, evidenced by a transient post-disturbance decoupling between above- and belowground biotic communities C_LIO_LIPresumed aboveground recovery can mask prolonged belowground disruptions, with potential implications for decomposition, nutrient cycling, and plant-microbe interactions C_LI

An organisms life history strategy is an attempt to optimize fitness, given environmental constraints and inherent demographic tradeoffs. As such, life history helps to shape an organisms ecological and evolutionary responses to environmental change. However, life history can also be shaped by the environment, as the organisms demographic rates respond--directly or through tradeoffs--to the new conditions. This feedback between life history and environment remains poorly understood, limiting our ability to predict the outcomes of environmental change. Here, we studied the effects of environmental change - specifically altered pollination services - on four perennial plant species. We conducted a field-based demography experiment that subjected naturally occurring populations of Delphinium nuttallianum, Hydrophyllum fendleri, Potentilla pulcherrima and Erigeron speciosus to three pollination treatments: ambient (control), reduced, or increased pollination. We estimated population growth rate ({lambda}) and 11 metrics describing life history strategy and demographic resilience from an Integral Projection Model we constructed for each species and parameterized with 4-5 years of census data. Although most life history metrics responded idiosyncratically to pollination treatment, we found consistent effects of pollination on generation time, longevity and, in three of four species, recovery time. Specifically, reduced pollination led to increased longevity, generation time, and recovery time, and increased pollination led to the opposite. These changes in life history resemble shifts along the slow-fast continuum; reduced pollination led to slower lives and increased pollination led to faster lives. This is consequential because generation time and longevity influence short- and long-term population dynamics - for example, by affecting demographic stochasticity and sensitivity to environmental stochasticity, or rates of adaptation to novel conditions. Notably, these changes occurred largely independent from changes in population growth. Altogether, our results highlight changes in life history as an important but underappreciated consequence of environmental change.

Local temperatures can shape the ability of introduced species to flourish and disrupt novel environments. The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive beetle that threatens ash trees in North America and Europe. To assess the role of temperature on EAB reproduction, we reared groups of adult beetles at one of four temperatures (12, 15, 18, and 21 {degrees}C) and measured reproductive success (laying fertilized eggs and egg hatching). There was no effect of rearing temperature on EAB female lifespans but no eggs laid at 15 or 18 {degrees}C hatched, suggesting these temperatures disrupt the reproductive process of EAB. Females reared at 21 {degrees}C, however, consistently laid eggs that hatched. We then used these results to assess the likelihood of reproductive success over the previous ten years in eight cities in Canada that host EAB. All locations experienced temperatures of [&ge;] 21 {degrees}C, but the number of hours and the number of days above this critical temperature were highly variable. There were ample opportunities in all locations for EAB to reproduce, but EAB in cooler cities would experience thermal limitations thus slowing the spread of EAB populations.