Large terrestrial mammalian herbivores (LMHs) play a critical role in ecosystems, but the effects of these species on belowground zoogeochemistry in forest ecosystems remain poorly understood. This study aimed to investigate the influence of LMHs on belowground processes in forest ecosystems. We synthesize current knowledge on how LMH species composition, physiology and feeding habits influence belowground litter and soil properties in boreal, temperate and tropical forests of the world through a systematic review. Tropical forests host the highest diversity of LMHs, but are the least studied, with most species being threatened frugivorous ruminants and non-ruminants. Temperate and boreal forests are more studied and dominated by ruminant browsers or mixed feeder species. The impact of LMHs shows high variation among forest types, but ruminants (Cervidae) tend to have negative effects on litter and soil properties in temperate and boreal forests, thereby decelerating nutrient cycling. Whereas LMHs non-ruminants (Suidae, Tapiridae and Tayassuidae) positively affect litter and soil properties in temperate and tropical forests. Research on the effects of LMHs on litter and soil properties faces several challenges, including confounding factors, such as biotic and abiotic conditions, high contextual variability influenced by factors, such as forest type, seasonality and experiment time, and there is also a geographical bias, with most studies conducted in temperate forests, while research in tropical forests remains scarce. LMHs are highly threatened by defaunation, which can disrupt ecosystem dynamics, highlighting the need to address research gaps. Long-term studies in tropical forests, particularly in South and Central America, Africa, India and Southeast Asia, are essential to understand the effects of LMHs on belowground properties. While LMHs are hypothesized to reduce nutrient cycling in forest ecosystems, this effect appears to be highly context dependent underscoring the need for further research. Understanding these effects is critical for advancing ecological knowledge and predicting climate change impacts on forest ecosystems. In addition, this can guide trophic restoration efforts and enhance ecosystem resilience.

Dynamic occupancy models, which estimate local colonization and extinction rates from detection/non-detection data collected across multiple sampling periods (e.g. years), are powerful but data hungry statistical tools. However, many ecological studies lack sufficient sample sizes to estimate these dynamic parameters. Autologistic occupancy models, which estimate occupancy patterns through time and account for temporal autocorrelation in a species occupancy status, offer a parsimonious alternative that is well suited for datasets with fewer sites or seasons of data. Here, I introduce the autoOcc R package, which can be used to fit autologistic occupancy models in a frequentist framework. This package also supports model comparison via the Akaike information criterion (AIC) and making predictions from fitted models, making it a flexible and accessible option for those with detection/non-detection data collected over time. Through simulations I show that autologistic occupancy models estimate parameters with less bias and more precision than dynamic occupancy models across a wide range of scenarios and sample sizes. These results suggest that autologistic occupancy models are a useful alternative when data are limited-a common constraint in ecological studies. To illustrate practical use of autoOcc I provide two worked examples: estimating habitat associations of Virginia opossum (Didelphis virginiana) throughout Chicago, Illinois, USA and quantifying spatiotemporal patterns in black-backed woodpecker (Picoides arcticus) distributions as a function of fire severity throughout California's montane forests. These examples demonstrate not only how to implement fitting autologistic occupancy models, but also how meaningful ecological inference can be drawn from them. By formally introducing this modelling framework and lowering the barrier for others to use, autoOcc increases the range of tools available for researchers that study species occupancy dynamics, especially when data are limited.

Climate warming has been associated with widespread body size declines in many vertebrate taxa, but relatively little is known about possible climate warming induced shifts in trait heritabilities. The main goal of the study was to investigate how changing food availability affects evolutionary potential of four traits related to nestlings' body size. We used long-term, pedigree structured data of two woodland passerines living in the boreal zone, the Willow Tit (Poecile montanus) and the Great Tit (Parus major), to study how food availability for their nestlings has changed in time, how this has influenced their morphological traits (viz. wing, tail & tarsus length & body mass) and their heritabilities and evolvabilities. This was done by assessing heritabilities under varying food availabilities using random regression animal models. We found that caterpillar food availability had increased over the 25-year-long study period and that this was accompanied by increases of nestlings' body mass, but not other morphological traits. All traits were heritable in both species, but additive genetic variance, heritability and evolvability were affected by food availability only in the case of the wing length, being higher under low food availability (the Great Tit) or higher under low and high food availability (the Willow Tit). We conclude that changes in food availability seem to have limited influence on evolutionary potential of body size traits in these two passerine birds.

Understanding how animals balance environmental constraints is essential for predicting species persistence under climate change. In thermally stratified lakes, cold water fishes such as brook charr (Salvelinus fontinalis) must navigate vertical gradients in temperature and oxygen to optimize foraging while avoiding physiological stress. We hypothesized that individuals would exhibit behavioural tactics that reflect a trade-off between accessing warm surface waters to exploit profitable prey and avoiding thermal stress, with greater constraints expected on epilimnetic use as surface temperatures rise. Using high-resolution acoustic telemetry, we quantified fine-scale patterns of thermal habitat use, vertical foray behaviour and diel timing in a wild brook charr population across the summer stratification period. We also assessed whether behavioural thermoregulation aligned with morphological differences, testing whether divergent behaviours reflect partial ecotypic divergence. As surface temperatures rose, brook charr reduced their use of the warm epilimnion, making fewer and shorter vertical forays. Hypolimnion use increased concurrently but was unrelated to limiting oxygen concentrations, indicating that deep water use was not physiologically constrained and may reflect an alternative foraging behaviour. Epilimnetic forays peaked at dusk and varied with moon phases, consistent with crepuscular visual foraging. Hypolimnetic use peaked at dawn and dusk but showed no response to moonlight. Diel patterns shifted seasonally: in warmer months, epilimnetic access was restricted to twilight hours, while cooler months saw broader surface use throughout the day. Principal component analysis of vertical movement and temperature exposure traits revealed two behavioural tactics: a 'warm' tactic, characterized by frequent epilimnetic forays and warmer average thermal exposure, and a 'cool' tactic, associated with greater hypolimnetic use and cooler average temperatures. These tactics corresponded with partial morphological divergence within the two sexes. Linear discriminant analysis showed that males following the warm tactic were morphologically distinct from cool ones, differing in traits related to feeding and swimming performance, while females showed weaker morphological differentiation. Together our findings reveal repeatable habitat use and consistent thermal tactics that reflect trade-offs between foraging and thermal stress. Vertical gradients in temperature and resource distribution may thus promote fine-scale individual specialization and phenotypic divergence in cold water species facing lake warming.

Host-parasite interactions increasingly are influenced by human-induced rapid environmental change (HIREC), and the fitness effects of parasitism may be compounded or exacerbated by host traits and/or exposure to additional extrinsic stressors associated with HIREC. Potential interactions between parasitism and different stressors associated with environmental change, however, remain poorly understood for most systems. We examined how parasitism by bird blow flies (Trypocalliphora braueri), ambient weather conditions and habitat disturbance jointly affected offspring traits and juvenile mortality for two declining species of sagebrush songbirds (Brewer's Sparrow, Spizella breweri; and Sage Thrasher, Oreoscoptes montanus) in Wyoming, USA. We evaluated two alternative hypotheses: that parasitism could act (i) in an independent and additive manner with temperature and habitat alteration (Multiple Stressors Hypothesis) or (ii) synergistically to exacerbate the effects of temperature and habitat alteration (Parasitism-HIREC Interaction Hypothesis) on offspring traits and juvenile mortality. We assessed morphometric traits of nestlings and survival of fledglings in relation to parasite loads, temperature and habitat disturbance associated with natural gas development to test these hypotheses. Higher parasite loads and colder temperatures were associated with different effects for nestlings of each host species, reducing tarsus and wing chord length for Brewer's Sparrow and increasing mass for Sage Thrasher. Despite differences in the effect of parasitism on nestling traits, post-fledging mortality risk for both species increased with higher parasite loads. The effects of parasitism and temperature mainly were additive, with limited evidence that weather exacerbated the effects of parasitism. Habitat disturbance had a weak positive effect on nestling tarsus length and post-fledging survival probability for Brewer's Sparrow. Although parasitism rarely results in direct mortality of hosts, parasites can nonetheless exert considerable fitness consequences, especially when combined with extrinsic stressors associated with human-induced environmental changes.

Rapid expansion of human activities has altered abiotic and biotic environments and reshaped the sensory systems of animal species. Auditory perception, a key sensory component of soniferous species, is essential for signal detection, species recognition and group coordination. Birds mitigate acoustic masking in fragmented habitats by actively modulating the spectral and temporal features of their songs. However, it remains challenging to determine whether these modulations are primarily driven by biotic factors (e.g. species interactions within varying community compositions) or by abiotic factors (e.g. island attributes). We surveyed bird communities on forested islands in the Thousand Island Lake region, China, using passive acoustic monitoring. We applied sound frequency-based analyses to examine the relationship between island attributes (area and isolation), acoustic assemblage composition (species richness, morphological and phylogenetic relatedness) and sound frequency modulation of birds on 12 islands. Our findings indicated that species competition within acoustic space led to various strategies of frequency modulation to avoid acoustic overlap. With increasing frequency overlap, birds exhibited greater variations in peak frequency and frequency range, reflecting decoupled modulation in which vocal adjustments occurred either upward or downward, depending on context. By disentangling the effects of community composition from island attributes, we found that acoustic overlap was intensified on remote and small islands, particularly among species with large body size or close phylogenetic relationships, driving acoustic niche partitioning. These findings highlight the importance of biotic interactions within animal communities in driving avian vocal production shifts, emphasizing the necessity of jointly considering community composition and gradients of abiotic factors when examining sensory adjustments.

Research Highlight: Allison, A., Conway, C., Goldberg, A., Morris, A., and Hakanson, E. (2025) Seasonal body mass dynamics mediate life-history trade-offs in a hibernating mammal. Journal of Animal Ecology. https://doi.org/10.1111/1365-2656.70160. Body mass is an important proxy of individual state, especially for animals in seasonal environments. Storage of energy, primarily as fat, decouples daily energy expenditure from current food availability, providing flexibility in how animals respond to temporal variability in conditions and resources. Hibernating mammals take this to the extreme among endotherms: By fattening extensively and entering prolonged bouts of energy-saving torpor, they can remain inactive for part of the year, which maximises their chances of survival until the productive season. Allison et al. (2025) used a large data set of annual body mass change to investigate among-individual variation in the extent and timing of pre-hibernation fattening, its ecological co-variates and survival consequences in the endangered northern Idaho ground squirrel (Urocitellus brunneus). Delayed fattening was a cost of reproduction for females. Relatively fat squirrels had increased survival over the hibernation season, which is likely explained by fatter individuals choosing to enter hibernation earlier to avoid predation risk, rather than an energetic constraint imposed by a short growing season. Allison et al. found support for hypotheses relating fattening dynamics to thermal conditions, conspecific density and possibly time limitation, but not to limited food availability or interspecific competition. These results provide insight into state-dependent behavioural decisions about activity in seasonal environments and their consequences for life-histories in an unusual model among endotherms. They are important also for informing management actions to help conserve this endangered species.

One hundred years have elapsed since Charles Elton (1924) described the periodic fluctuations in North American snowshoe hare abundance, yet mechanisms underlying 9-11-year population cycles in snowshoe hares continue to be debated. We applied multistate capture-mark-recapture models to long-term field data (1977-2020) based on >20,000 captures of >7000 unique snowshoe hares (Lepus americanus) from Kluane Lake, Yukon, Canada, to estimate and model state-specific demographic parameters. Juveniles had the lowest and reproductive adult females the highest apparent survival. Apparent survival of all sex-age classes was highest during the mid- and late-breeding seasons and was generally better during the increase phase. Conditional probability of females transitioning from non-reproductive to reproductive state, and reproductive females remaining in the reproductive state, increased substantially as the population transitioned from low to increase phase throughout the breeding season. Analysis of stage-structured matrix population models revealed that population-dynamic characteristics were strongly phase-specific, and also varied across seasons, with the increase phases being characterized by high monthly asymptotic population growth rate. Snowshoe hares experienced short stage-specific generation time during the early breeding season across all phases; they experienced relatively long generation time during the increase and low phase of the mid-breeding season, and the increase and peak phase of the late breeding season. Elasticity analyses showed that asymptotic population growth rate was proportionately most sensitive to changes in survival of adult females across all phases and seasons. However, retrospective life table response experiment analysis showed that rapid growth of the snowshoe hare populations during the increase phase was due to improvements in reproductive transitions and pre-weaning survival, whereas population declines are caused primarily by reduced survival (primarily, pre-weaning survival), with reduced reproductive transitions and smaller litter sizes playing a secondary role. Our results suggest that cyclic populations of snowshoe hares are characterized by complex demographic and population-dynamic patterns, depending on phase of the cycle and reproductive season, and that different demographic mechanisms underlie rapid population growth during the increase phase, and swift population declines as the population transitions from the peak to the decline phase. Because our study represents the first comprehensive demographic and population-dynamic study of a cyclic population, similar studies would be needed to test the generalities of our conclusions. Whereas density-dependent predation has been shown to be the primary cause of phase-related changes in survival, future research should focus on identifying mechanisms underlying phase-related changes in reproductive parameters.

Large herbivores can strongly influence plant communities. However, these effects are highly variable, potentially depending on the herbivore regime, that is, herbivore diversity and density. However, the role of the herbivore regime has been challenging to evaluate across spatial scales due to widespread defaunation and a lack of data on herbivore communities and their densities. Here, we investigated the effects of large herbivores along a gradient of trophic complexity (low to high herbivore diversity) and herbivory intensity (estimated from herbivore biomass and visitation frequency) on plant taxonomic and functional diversity at different scales (plot [n = 250], site [n = 50] and landscape [n = 10]) in 10 reserves in the savanna biome in South Africa. We found higher total plant species richness, driven by higher herbaceous (but not woody) plant species richness, in areas with higher herbivory intensity across multiple scales. While herbivores had no significant relationship with plant functional richness, we observed higher functional redundancy at all scales in areas more frequently visited by herbivores. Overall, herbivore-vegetation relationships were largely consistent across scales, and the strongest effects emerged at the largest scale. Our results show a positive relationship between large herbivores and both herbaceous plant species richness and plant functional redundancy, the latter suggesting higher vegetation resilience (the capacity of ecosystems to quickly recover from disturbances as different species compensate for the loss or decline of others). These effects are largely consistent across scales, indicating that the impact of herbivore regimes on plant communities is predominantly scale-independent and that large herbivores drive vegetation dynamics at both local and large scales. However, the stronger effects observed at the landscape scale imply that herbivore impacts manifest most prominently at larger scales. Altogether, our results suggest that restoring large herbivore populations can be expected to promote herbaceous plant diversity and ecosystem resilience.

Body size is one of the most important traits governing individual-level demographic rates and modulating population-level processes. Multiple size-dependent demographic rates can simultaneously change population structure, so distinguishing their individual contributions to overall population dynamics remains a challenge. Disentangling size-dependent harvest rates from other demographic rates is critical for assessing the impact of removal on populations of invasive species. Inference about invasive populations can be difficult, however, as observations are often collected opportunistically as part of removal programs, rather than experimentally designed. Yet accurate inference is essential for understanding the feasibility of population suppression and optimising management decisions. We develop an integrated integral projection model (IPM) that leverages the strengths of the integrated population model and integral projection model to enable inference about complex, size-structured demographic rates from imperfect observations. We apply the IPM in the context of invasive European green crab (Carcinus maenas), a species for which individual body size strongly regulates both the observation-generating process and latent, population dynamics. The IPM facilitates the distinct estimation of green crab size-structured harvest and natural mortality rates, parameters for which no explicit data is collected and that are unidentifiable in component datasets of the integrated population model. The model represents how the green crab population changes over time, providing the first estimates of size-structured abundance of this high-priority species. By forecasting the stable size distribution and equilibrium population size under varying removal efforts, we demonstrate that extremely high levels of removal effort can reduce the equilibrium green crab population size. Yet these high mortality rates also shift the stable size distribution and increase the equilibrium abundance of smaller crabs, since size-selective removal alters intraspecific interactions. The ecological outcome of this shift in size structure will be variable, as green crab size modulates only some of its interactions with other species. These results highlight the value of the IPM framework for inferring complex population dynamics with information needs that outpace information in individual observational datasets, providing a path forward for accurate assessment of conservation programs.

Understanding how sympatric predators coexist remains a central question in community ecology, particularly when those species are phylogenetically related obligate carnivores with similar body sizes and trophic roles. In the neotropics this challenge is particularly salient because jaguars (Panthera onca), pumas (Puma concolor), ocelots (Leopardus pardalis) and margays (Leopardus wiedii) are broadly sympatric pairs of large- and medium-bodied hypercarnivores in apparent violation of the principle of limiting similarity. We conducted a comprehensive multi-dimensional analysis of coexistence mechanisms among two large-bodied (jaguars and pumas) and two medium-bodied (ocelots and margays) felids by quantifying spatial, temporal, and dietary niche partitioning in the Maya Biosphere Reserve, Guatemala. To do so, we integrated high-resolution fecal DNA metabarcoding using extant and novel assays, ground and arboreal camera trapping and abundance-mediated species interaction models. Contrary to expectations, we found little evidence for body size-based prey partitioning among pairs of similarly sized felids. Instead, vertical dietary partitioning driven by selection of arboreal versus terrestrial prey emerged as the dominant axis of niche differentiation. Jaguars specialized on large terrestrial prey-notably peccaries-and armadillos, while pumas exhibited high consumption of arboreal primates. Among smaller felids, despite high uncertainty, margays appeared to more strongly select arboreal prey. Also contrary to expectations, we found little evidence for spatial segregation, even among species with potential for interference competition. Despite high rates of intraguild predation observed between certain species pairs, jaguars, pumas and ocelots exhibited positively associated capture rates. Abundance-mediated interaction modelling revealed weak to no evidence of interspecific interactions between the species driving spatial or temporal variation in abundance. Likewise, pairs of felids with similar body sizes had broadly overlapping daily activity patterns. However, temporal activity patterns reduced overlap between large- and medium-bodied felids, suggesting diel shifts may help mitigate interference competition and intraguild predation. Our findings highlight arboreal versus terrestrial prey selection as a key mechanism facilitating coexistence among size-based species pairs in neotropical forests. We demonstrate the benefits of incorporating high-resolution diet analysis, canopy camera trapping and arboreality assessments into future tropical carnivore ecology research to reveal how vertical niche dynamics facilitate species coexistence.

Research Highlight: Oli, M., Kenney, A., Boonstra, R., Boutin, S., Murray, D., Jung, T., Hines, J., Krebs, C. (2025). Demographic mechanisms of snowshoe hare population cycles in Yukon, Canada. Journal of Animal Ecology. https://doi.org.10.1111/1365-2656.70169. Ecologists have long been intrigued by cycles in population abundances characterizing the dynamics of some wild species. Abundance may follow surprisingly regular cycles, with an increase phase, a peak phase and then a decline phase of more or less the same length. Predator-induced mortality has long been proposed as the main demographic mechanism inducing population cycles, leading most of cycle theory to consider that population cycles result from survival changes only. In this paper, Oli et al. (2025) assessed how the cycles in population abundance of the snowshoe hare (Lepus americanus) in Yukon, observed during 43 years, are driven by survival or reproductive rates of some specific age classes and how their contributions differ according to the cyclic phase. Thanks to the individual monitoring of more than 7000 snowshoe hares and a state-of-the-art capture-mark-recapture modelling framework, they showed different contributions of age-specific vital rates to the population growth rate, depending on the cyclic phase (increase, peak, decline and low phases) and the breeding period considered (early, mid, late and non-breeding periods). For instance, improved breeding probability, litter size and pre-weaning survival played a major role during the increase phases, whereas lower pre-weaning survival explained population decline. They also highlighted a strong interaction between season and cyclic phases, with, for example, at mid-breeding season, a survival in low phases that is close to the survival observed in increase phases. This led to different life-history strategies over the seasons and the phases: the population had a fast strategy in the early breeding season in the increase phase and a slow strategy in the late breeding season and decline phase, demonstrating a high level of plasticity across phases and seasons. The enigma of population cycles is not fully solved yet, but the study by Oli et al. (2025) clearly contributes to improving our mechanistic understanding of population cycles.

Migratory birds often navigate inhospitable barriers (e.g. oceans, deserts) during migration. Barrier crossings are frequently associated with increased rates of mortality and likely impose selective pressures on migratory species that shape their behaviour and distribution. Therefore, understanding how weather conditions influence the behaviour of migratory birds at a major barrier can provide insight into the adaptive evolution of long-distance migrations involving barrier crossings and how changing climatic conditions might affect migratory species in the future. We used light-level geolocator data from 89 individual Vermivora warblers to identify the weather conditions associated with individuals initiating barrier-crossing flights across the Gulf of Mexico (i.e. 'trans-Gulf flights') during both autumn and spring migrations from 2013 to 2017. Weather conditions associated with the initiation trans-Gulf flights differed between autumn and spring. In autumn, the initiation of trans-Gulf flights was positively associated with favourable wind conditions and temperature but negatively associated with relative humidity and 24-h change in barometric pressure. During spring migration, the initiation of trans-Gulf flights was negatively associated with surface-level relative humidity and barometric pressure but not associated with wind conditions. We found that the frequency of days with weather conditions associated with a high-predicted probability of Vermivora warblers initiating trans-Gulf flights varied geographically (range 0%-58% of days). Distinct breeding populations of golden-winged warblers (V. chrysoptera) with strong migratory connectivity between breeding and non-breeding regions exhibited weak migratory connectivity and overlapped extensively during migration immediately prior to initiating trans-Gulf flights. Breeding populations of blue-winged warblers (V. cyanoptera) exhibited weak migratory connectivity and co-occurred during both autumn and spring migrations and during the non-breeding period. The weak migratory connectivity that we observed in Vermivora warblers prior to crossing the Gulf of Mexico may be shaped by shared evolutionary responses to consistent synoptic weather conditions in the region. Predicted future climate conditions including increased humidity and more frequent and/or severe storms may decrease the favourability of conditions associated with initiating trans-Gulf flights during spring migration for Vermivora warblers, which could negatively affect populations.

Diversity in life-history strategies is a key aspect of population resilience. However, the spatial and environmental factors that drive this variation remain poorly understood. In a recent study, Shida and Sato combined year-round surveys of water temperature, prey abundance, growth and life-history traits in masu salmon (Onchorhynchus masou) across a river continuum (i.e. from tributary to mainstem river). The authors show that shifting growth opportunities along the river, influenced by thermal and trophic resources, generate differences in age at maturity while maintaining high within-habitat (alpha) diversity. These findings provide an important example of how spatiotemporal habitat heterogeneity influences phenotypic diversity and highlights the role of both environmental and intrinsic factors shaping the population-level variation in life-history strategies.

Climate change is increasing the frequency, intensity and duration of droughts. While much is known about the effects of drought on herbivores, its impact on carnivore ecology and demography remains poorly understood. Drought may benefit large carnivores by increasing prey vulnerability but can also increase intra- and interspecific interactions and competition. We assessed how a severe drought influenced the diet, space use and reproduction of leopards and lions in South Africa's Sabi Sands Game Reserve, focussing on their contrasting ecology and dominance. Despite an increase in energetic gain, leopard reproductive success declined significantly during the drought, primarily due to increased vulnerability of cubs to intraguild predation. Lions also increased their net energetic gain during drought and, while they showed a marginal increase in cub survival, this was offset by a mange outbreak. These findings challenge the conventional assumption that drought universally benefits large carnivores. For leopards, a subordinate carnivore, the top-down pressures of competition and predation outweighed bottom-up benefits of prey vulnerability. Lions, the dominant competitor, benefitted from increased prey vulnerability and decreased intraspecific conflict but remained vulnerable to stochastic external factors. This underscores the complex interplay of environmental stress, predator interactions and reproductive success, with important implications for carnivore conservation under increasing drought frequency and severity in semi-arid systems.

Global warming causes spring onset to advance, especially in the Arctic. Migratory animals may respond by advancing their phenology or colonising colder areas where spring starts later. The role of climate change in range expansion can be both driving (making traditional areas suboptimal) and facilitating (making new areas suitable). Recently, Pink-footed Geese (Anser brachyrhynchus) from Svalbard showed extreme range expansion by colonising the colder Novaya Zemlya as breeding ground, involving a new migration route. We examine potential costs and benefits associated with breeding in this new area. We use GPS-tracking, long-term population monitoring and remote sensing, to compare spring onset, migration timing and breeding performance between both flyways, and to evaluate how spring onset affects different reproductive stages in both breeding areas in these capital breeders. The traditional route showed challenges for migration timing, as spring had advanced in Svalbard (while arrival date had not kept up) but not on stopovers, and recently, early spring on Svalbard correlated with late spring on stopovers. On new stopovers, spring did advance. Spring was later in Novaya Zemlya than Svalbard, yet arrival dates were similar. In Novaya Zemlya, egg laying occurred later than in Svalbard, but still earlier relative to local spring onset (e.g. snowmelt and green-up), suggesting a smaller mismatch. The period between arrival and egg laying was longer in Novaya Zemlya than Svalbard, but breeding performance was similar. Finally, on the new route, geese were larger and (relatively) heavier than on the traditional route, thus possibly carrying larger capital body stores to cover harsher pre-laying periods. Our results suggest that colonising new breeding areas enables populations to regain phenological match with the environment, especially when advancement of migration timing was limited. Still, breeding in a colder area may require more parental investment, such as body stores. Thus, a benefit for offspring comes at a cost for parents. This mechanism can cause climate change to drive and facilitate colonisation especially in individuals capable of large investments. Consequently, variation in individual quality leads to heterogeneous effects of climate change within a population. These processes may play at the 'cold' edge of any range shift.

Artificial intelligence (AI) technology has the potential to revolutionize entomology and biodiversity research, allowing entomologists to address biodiversity questions on a larger scale than ever before. A new software program, called BugBox, has been developed to facilitate large-scale arthropod bioinventories. BugBox uses an AI algorithm to rapidly classify arthropods from specimen photographs and calculates per-sample diversity indices from its classifications. We evaluated the performance of the AI algorithm over three consecutive training cycles by comparing the AI's classifications to identifications conducted by a human expert. We also used both AI and human data to separately test the hypothesis that regenerative agricultural practices increase arthropod biodiversity in a bioinventory from North American rangelands. BugBox demonstrated substantial improvement in all test metrics over the three cycles as it was allowed to incorporate the human expert's corrections into each new model version (e.g. f1 score improved from 0.523 to 0.722 over the four consecutive model versions). AI classifications were strongly correlated with human identifications, and the AI drew the same conclusion as the human data when comparing diversity indices (Hill numbers): both found evidence that regenerative practices increased arthropod diversity. These results demonstrate that, while the AI was less accurate than the human, it was still able to provide useful surrogate data at scale very rapidly. It can also improve over time under the guidance of human expertise. This technology has profound implications for the scalability of entomological science.

The ephemeral resource patch (ERP) concept provides a framework for understanding how finite, short-lived resources shape community assembly processes at both patch and landscape scale. Some of these theories and principles can be applied to intermediate-lived resources, such as deadwood, but this remains largely unexplored. We tested three ecological mechanisms of community assembly (more-individuals hypothesis, habitat-heterogeneity hypothesis and habitat filtering) to investigate whether beetle assemblages in deadwood fit the ERP concept. We tracked saproxylic beetle communities in experimental logs of Norway spruce (Picea abies), European silver fir (Abies alba) and beech (Fagus sylvatica) in the temperate mountain forest of the Bavarian Forest National Park over a 12-year decomposition period, from the early decomposition stage until near-complete resource depletion. Beetle abundance and number of species declined consistently in all tree species until the 4th year but increased again in spruce after ~8 years. Species richness (number of species controlled for abundance) showed inconsistent patterns over time: U-shaped for spruce, weakly hump-shaped for fir and no temporal effect for beech. Habitat filtering was more pronounced in the early stage as functional diversity was initially low but increased for all tree species up to 4 years, then plateaued and increased again after ~10 years for both conifers. Conditional inference tree identified two temporally distinct beetle assemblages (years 1-3 and 4-12), and strong differences within the first 4 years. Our findings suggest that the more-individuals hypothesis and habitat filtering are key mechanisms driving community assembly in saproxylic beetles. Early decomposition stages supported functionally similar assemblages, highlighting this phase as a critical period for decomposer community structuring. Synthesis. The consistency of the early successional trajectories of beetles suggests that the early stages of deadwood decomposition up to the 3rd year in the temperate zone follow ephemerality theories similar to those of short-lived ERPs, while the advanced stages provide a habitat for a more random combination of beetle species. Furthermore, our findings highlight the need for temporally continuous deadwood input, via natural processes or staggered retention during logging operations, to provide coarse woody debris for wide range of saproxylic beetles.

The natal multimammate mouse (Mastomys natalensis) is the primary reservoir host of Mammarenavirus lassaense (LASV), a zoonotic pathogen causing Lassa fever and endemic to West Africa. The occurrence and abundance of this species is regulated by the human environment and biotic interactions with other small-mammal species, but these ecological drivers remain poorly understood in the regions where Lassa fever outbreaks are observed. We developed a Bayesian multi-species occupancy model incorporating incomplete detection to assess habitat use from data obtained as part of a multi-year small-mammal trapping study (43,226 trap nights across four village sites in Sierra Leone, 2020-2023). We investigated the effects of land use gradients and small-mammal community dynamics on the spatial distribution of M. natalensis. Mastomys natalensis occupancy increased along a gradient from forest to agriculture to village habitats but was reduced in the peri-urban site compared to rural settings. Invasive rodent species influenced this pattern, with Mus musculus presence associated with reduced M. natalensis occupancy in the peri-urban site. We did not observe a similar effect when considering the co-occurrence of invasive Rattus rattus with M. natalensis in rural settings. These findings suggest that land use and species interactions drive spatial heterogeneity in M. natalensis populations, potentially explaining reduced Lassa fever incidence in urban areas. The results highlight the importance of considering community dynamics when predicting the risk of outbreaks of endemic zoonoses and the need to widen the context of studies of LASV transmission beyond the primary reservoir host species. To better assess public health risk and improve allocation of limited resources, we recommend more precise characterisation of small-mammal communities in LASV endemic regions, particularly in areas undergoing rapid land use change which may alter community-level small-mammal biodiversity.

Animals aggregated on habitat patches can generate nutrient "hotspots" that enhance biogeochemical cycling and primary production, yet the conditions under which such hotspots emerge in continuous reef habitats remain unclear. This study aimed to determine how different scales of reef structural complexity regulate fish-derived nutrient supply and associated benthic enrichment. We conducted fish surveys and high-resolution photogrammetry across six reefscapes (~2500 m each) in the Florida Keys, USA. At the 25 m scale, we quantified large-scale vertical relief and fine-scale complexity using vector ruggedness (VRM), estimated nitrogen (N) and phosphorus (P) supply from fish bioenergetics models, and measured macroalgal tissue %N and %P. We found that fish-derived nutrient supply increased with reef vertical relief up to ~2.8 m, beyond which supply rates saturated. VRM was positively related to nutrient supply, particularly in low-relief areas, indicating scale-dependent effects. Macroalgal nutrient content was non-linearly related to supply, with uptake plateauing above ~250 mg N m day and ~35 mg P m day. Nonlinear patterns were driven by high-relief hotspots, where nutrient supply was several times greater than surrounding reef. These findings show that mesoscale habitat complexity interacts across scales to shape consumer-driven nutrient supply and benthic enrichment. Identifying thresholds in relief and VRM provides new insight into when and where nutrient hotspots form and offers practical guidance for targeting restoration to reef features most likely to enhance productivity.

Projecting the effects of future climate conditions for predator-prey systems can be challenging, because species' environmental tolerances can differ and both environmental reaction norms and predator functional responses are nonlinear. We addressed this issue in the context of Eastern oysters (Crassostrea virginica) in the Gulf of Mexico, USA. Oysters are an ecologically and economically important estuarine species threatened by a variety of stressors including prolonged exposure to extremely low or high salinity. In this region, a major oyster predator, the southern oyster drill (Stramonita haemostoma) thrives at high salinity and is impaired by low salinity. As estuarine salinity becomes more variable (e.g. more regional droughts leading to prolonged high-salinity conditions), one might expect drill predation to become more intense, as when high salinity led to a predator-driven oyster population collapse in Apalachicola Bay, FL in 2012. To test that expectation, we simulated the dynamics of a two-species integral projection model with salinity-dependent demography for both species, including size-structured and salinity-dependent predator feeding behaviour, based on laboratory experiments. We forced the model with simulated salinity time series that matched the climatology and autocorrelation structure of historical salinity in Apalachicola Bay, but with increased standard deviation, reflecting the range of increased variability in regional precipitation over future decades predicted by global climate models. Surprisingly, the model predicted that the expected range of increased salinity variability had little effect on oyster abundance or the probability of quasi-extinction. A sensitivity analysis revealed that this was because the negative effects of salinity variability on oysters were mostly balanced out by the inhibition of drill predation by low-salinity anomalies. Additionally, the negative effects of increasing salinity variability could be counteracted by increasing drill mortality (such as by manual culling). This analysis illustrates the importance of accounting for environmentally dependent species interactions when forecasting climate-driven changes to population dynamics.