The Journal Of Animal Ecology[JOURNAL]
Sun
200 papers
On traits matching and the modular organization of food web and occurrence networks.
Borzone Mas D, Scarabotti PA, Vaschetto PA … +3 more , Alvarenga P, Vazquez M, Arim M
J Anim Ecol · 2026 May · PMID 41840807 · Full text
Modularity and nestedness have been observed recurrently across different ecological networks, including food webs and occurrence networks. These patterns emerge from species-level processes, where interactions and occur...
Modularity and nestedness have been observed recurrently across different ecological networks, including food webs and occurrence networks. These patterns emerge from species-level processes, where interactions and occurrences are determined by niche-based and/or abundance-based mechanisms. Abundance-based processes promote nested networks with gradients in the number of links determined by species abundances. Niche-based processes can promote modular structures due to differential spatial filters or trait matching in discontinuous gradients of predators and prey traits or nestedness due to gradients in the strength of environmental filters or trait limitation for consumption. Here, we explore the mechanisms driving species-level interactions and the resulting network structure in both food webs and occurrence networks of piscivorous fishes from the Paraná River. Our study focused on 16 species of piscivorous fish. We constructed occurrence networks (149 communities, 3010 observations) and food webs (113 prey species, 1271 trophic interactions). Using null models, we assessed modularity and nestedness in both types of networks, as well as the existence of significant deviations in the trait composition, functional diversity and community-weighted mean among modules. Moreover, we assessed the relationship between species abundance and degree to identify the potential role of abundance-based processes. Occurrence networks and food webs exhibited a modular structure, with no evidence of nestedness. In both networks, niche-based mechanisms played an important role. Each module showed a distinct representation of habitat types in occurrence networks and prey types in food webs. A significant relationship was also observed between predator abundance and the number of interactions or occurrences, suggesting that abundance-based mechanisms also contribute to network organization. Here, we are getting ahead in understanding the mechanisms driving ecological organization in piscivorous fishes from the Middle Paraná River. Although food webs and occurrence networks represent distinct dimensions, our results reveal a consistent pattern: both are shaped by a combination of abundance- and niche-based processes. This convergence highlights shared principles of network assembly across contexts. By disentangling the contributions of these mechanisms, our findings advance ecological theory and highlight that protecting functional diversity and resource heterogeneity is essential for preserving the structure of ecological networks.
Effects of temperature and browning on the functional response of a freshwater top predator.
Nilsson-Örtman V, Nilsson E, Brönmark C
J Anim Ecol · 2026 May · PMID 41840780 · Full text
Freshwater lakes are becoming warmer and browner, with poorly known ecosystem consequences. A major unresolved issue is how these changes will affect the feeding rates of predators that regulate top-down trophic cascades...
Freshwater lakes are becoming warmer and browner, with poorly known ecosystem consequences. A major unresolved issue is how these changes will affect the feeding rates of predators that regulate top-down trophic cascades. We explored the effects of temperature and browning on the functional response and feeding rates of a keystone predator, the Northern pike Esox lucius. We first derived a simple mechanistic model on the effect of temperature and browning on predator feeding rates. To test predictions from the model, we performed two laboratory experiments where we estimated pike functional responses in brown and clear water at three temperatures and quantified feeding rates along a gradient from completely clear to extremely brown. We find strikingly weak effects of temperature and browning on pike feeding rates, even under extreme levels of browning. Pike showed an asymptotic Type II functional response under most conditions but switched to a dome-shaped Type IV functional response in cold clear water, possibly due to seasonal changes in the schooling behaviour of prey. Our results suggest that temperature and browning may have interactive effects on predator functional responses mediated via changes in prey behaviour and support the view that browning affects piscivorous fish mainly through bottom-up effects rather than changes in foraging efficiency.
Eco-evolutionary dynamics of partially migratory metapopulations in spatially and seasonally varying environments.
Haaland TR, Payo-Payo A, Acker P … +5 more , Fortuna R, Burthe SJ, Ratikainen II, Daunt F, Reid JM
J Anim Ecol · 2026 Jun · PMID 41821235 · Publisher ↗
Interlinked population dynamic and evolutionary responses to spatial and seasonal environmental variation, stemming from interactions and feedbacks among phenotypic variation, genetic variation, selection and demography,...
Interlinked population dynamic and evolutionary responses to spatial and seasonal environmental variation, stemming from interactions and feedbacks among phenotypic variation, genetic variation, selection and demography, could generate complex eco-evolutionary dynamics that span temporal and spatial scales. Partially migratory metapopulations (PMMPs), featuring sequential seasonal sympatry and allopatry of different sets of resident and seasonally migrant individuals, have clear potential for such eco-evolutionary outcomes. This is because ongoing evolution of reversible seasonal migration affects spatio-seasonal population dynamics and densities, which could in turn shape forms and magnitudes of selection on migration, causing feedbacks on evolution. However, key environmental and genetic conditions that maintain migratory polymorphisms, and resulting eco-evolutionary dynamics of PMMPs given stochastic environmental variation and strong spatially restricted seasonal perturbations, have not been characterized. We built a general individual-based model that tracks eco-evolutionary dynamics in PMMPs inhabiting spatially structured and seasonally varying landscapes, with seasonal migration formulated as a quantitative genetic threshold trait. Simulations showed that such genetic architectures and landscape structures, which are common in nature, readily produce stable partially migratory systems given diverse regimes of environmental variation. Partial migration is maintained whenever sites differ in non-breeding season suitability, defined as variation in density-dependence, causing 'ideal free' non-breeding distributions where residents and migrants occur with frequencies generating similar survival probabilities. Further, bet-hedging can cause stable partial migration without any fixed differences in non-breeding season density-dependence among sites and even without density-dependence at all, given sufficiently large stochastic environmental fluctuations among sites and years. Importantly, major local non-breeding season mortality events, as could result from extreme climatic events, generate eco-evolutionary dynamics that ripple out to affect breeding and non-breeding season space use of subpopulations throughout the PMMP, on both short and longer timeframes. These effects result from spatially divergent selection on the occurrence and destination of migration. Our model thus shows how changing partial seasonal migration acts as a key mediator of eco-evolutionary dynamics in (meta)populations occupying spatially and seasonally varying environments. It thereby initiates new steps towards predicting responses of natural partially migratory populations to ongoing changes in spatio-seasonal patterns of environmental variation.
Foraging offsets declining fitness: Evidence of behavioural compensation for reproductive senescence.
Levine RL, Wagler BL, Rafferty RT … +7 more , Smiley RA, Jakopak RP, Randall J, Fieseler T, Scurlock B, Monteith KL, LaSharr TN
J Anim Ecol · 2026 Jun · PMID 41800475 · Publisher ↗
Animals face declining fitness contributions near the end of life, termed reproductive senescence. Though reproductive senescence frequently stems from physiological inefficiencies, animals making their final attempts at...
Animals face declining fitness contributions near the end of life, termed reproductive senescence. Though reproductive senescence frequently stems from physiological inefficiencies, animals making their final attempts at reproduction have the greatest incentive to succeed, raising the question of whether this deterioration is inevitable or if they can compensate to enhance fitness. Here, we examined whether foraging effort serves as behavioural compensation for reproductive senescence in female mule deer (Odocoileus hemionus). We expected that, as animals approach the end of their lifespans, they would increase foraging effort as a means of compensating for declining reproductive output. To assess compensatory foraging, we disentangled two components of lifetime fitness: energy acquisition and allocation. We used animal-borne activity sensors to quantify foraging effort (time devoted to energy acquisition) and followed animals across the annual cycle to measure reproductive output and seasonal fluctuations in stored energy (body fat). Then, we evaluated whether foraging effort mediated the effect of age on allocation to current reproduction and future fitness contributions. For senescing animals, foraging effort positively influenced newborn size, providing evidence of compensation for declining fitness contributions. Moreover, we detected a possible diversion of resources away from future survival and to current reproduction. Senescing animals with high foraging effort accumulated little fat over summer, likely diverting incoming energy to finance current reproduction (lactation) over future fitness. Our work demonstrates that, facing their final opportunities to reproduce, animals may use behaviour to compensate for the physiological declines associated with aging to improve their chances of reproductive success. By evaluating the role of behaviour in fitness components, we reveal processes underlying senescence, and its alleviation, in wild populations.
Functional and phylogenetic clustering shape rodent co-occurrence via multi-scale mechanisms in a subtropical forest.
Yang X, Yan C, Wang M … +5 more , Cheng C, Teng Y, Zhao K, Li Y, Zhang Z
J Anim Ecol · 2026 May · PMID 41789467 · Publisher ↗
Species co-occurrence has been widely investigated in various animal species, yet the roles of trait similarity, scatter-hoarding behaviour and habitat factors remain incompletely understood. We examined the effects of t...
Species co-occurrence has been widely investigated in various animal species, yet the roles of trait similarity, scatter-hoarding behaviour and habitat factors remain incompletely understood. We examined the effects of three groups of factors-functional similarity (i.e. phylogenetic, body size, diet), scatter-hoarding behaviour (i.e. scatter-hoarding intensity) and habitat factors (i.e. patch size, seed richness, seed abundance and stand age)-on species co-occurrence probability among sympatric rodent species with 7 years of field data using live and camera traps in a subtropical forest. At the community level, we assessed phylogenetic and functional structure using null model approaches and developed an abundance-weighted average species co-occurrence probability (ASCp) to evaluate assembly mechanisms. We found the species co-occurrence probability of rodents was significantly and positively associated with phylogenetic relatedness, body size similarity and diet similarity of pairs of rodent species using live traps at the species-pair level (such correlations were significant only for phylogenetic relatedness and diet similarity using camera traps). Species co-occurrence probability of rodents was significantly and positively associated with scatter-hoarding intensity using both methods. Community-level analyses revealed significant phylogenetic clustering and functional clustering in scatter-hoarding intensity and diet breadth, supporting a dominant role of environmental filtering. At the community level, ASCp was significantly and positively correlated with patch size when assessed using camera traps, and significantly and negatively correlated with stand age using live traps. Notably, ASCp positively correlates with community-weighted scatter-hoarding intensity, though this effect weakens in larger patches. Our results suggest that species traits, scatter-hoarding behaviour and habitat factors independently shape species co-occurrence patterns of rodents in forest ecosystems across multiple spatial scales, but the underlying mechanisms are distinct, which is explained by environmental filtering (traits), reciprocal pilferage (scatter-hoarding) and habitat heterogeneity (patch habitat factors), respectively. The species co-occurrence probability patterns showed some differences between the two methods, probably because animals may exhibit different responses or sensitivities to various survey approaches.
Environmental drivers of metapopulation dynamics throughout the full annual cycle in a declining Arctic-nesting migratory herbivore.
Schindler AR, Fox AD, Walsh AJ … +3 more , Griffin LR, Kelly SBA, Weegman MD
J Anim Ecol · 2026 May · PMID 41782578 · Full text
Assessing the impacts of changing environmental conditions on animal species requires thorough understanding of population dynamics, which can be difficult to estimate when animals aggregate into spatially discrete subpo...
Assessing the impacts of changing environmental conditions on animal species requires thorough understanding of population dynamics, which can be difficult to estimate when animals aggregate into spatially discrete subpopulations. We used 39 years of fecundity, capture-recapture and abundance data in an integrated metapopulation model to study environmental drivers of demography in a declining migratory bird, the Greenland white-fronted goose (Anser albifrons flavirostris). We found that low fecundity due to earlier spring vegetation phenology on staging areas and increased snow on breeding areas explained metapopulation decline, though the strength of these effects varied by subpopulation. Differential immigration and emigration rates affected local wintering abundance trends, highlighting the importance of quantifying subpopulation-metapopulation dynamics for understanding fragmented animal populations. We provide a framework for extending commonly used integrated population models to a metapopulation framework for testing novel ecological hypotheses about how changing environmental conditions within and among subpopulations drive changes in animal abundance.
Environmental phenology drives spring migration timing.
Bourski OV
J Anim Ecol · 2026 Apr · PMID 41744391 · Publisher ↗
Despite the obvious shift in spring bird migration to earlier dates, the mechanism behind this process remains unclear, partly due to inappropriate climate predictors. Information on the influence of climate is not geogr...
Despite the obvious shift in spring bird migration to earlier dates, the mechanism behind this process remains unclear, partly due to inappropriate climate predictors. Information on the influence of climate is not geographically representative, as it comes almost exclusively from the marginal parts of the continents. The objective of this study is to investigate the mechanism for determining the timing of spring terrestrial bird migration based on a new concept of environmental phenology and phenological navigation, using data from Central Siberia as an example. A literature review suggests that migrants follow the phenology of food resources, the dependence on which intensifies towards the end of migration with increasing seasonality of temperature conditions. We propose the concept of environmental phenology as a mediator between the influence of climate and the response of migrants. We defined the environmental phenology index as the average weighted temperature of the preceding days with weights decreasing exponentially in retrospect. Using original data from the first arrival dates of 145 species in Central Siberia from 1976 to 2025, we demonstrated the effectiveness of the environmental phenology index in predicting arrival dates. This indicator reflects the accumulation of climate information by numerous ongoing phenological processes. Due to its high autocorrelation, it predicts future foraging conditions. Despite significant warming at the study site (0.60 degrees per decade), bird arrival dates in the studied community responded to warming with a slight shift towards earlier dates: on average, by -0.91 days per degree annually and by -0.86 days per decade. These estimates are lower than those known for other regions due to the pronounced continental climate and the steep rise in spring temperatures (1 degree in 3 days). We believe the compensated share of this impact (the response to impact ratio) to be a more adequate measure of the organism's response to the impact. Based on the study results, we propose a mechanism of phenological navigation, in which a migrant at each stopover chooses whether to move on or wait for changes based on the relationship between environmental phenology and day length. This simple scheme opens new possibilities for comparing the phenological responses of different groups of organisms. The proposed index of environmental phenology is theoretically and practically substantiated, expands the understanding of the mechanism of phenological navigation and can be used to solve similar phenological issues.
Environmentally induced stress affects fitness of bold and shy alike: A long-term study of personality and feather corticosterone in Arctic-breeding kittiwakes.
Mckendrick FC, Patrick SC, Descamps S … +4 more , Will AP, Arnold KE, Harris SM, Kitaysky AS
J Anim Ecol · 2026 May · PMID 41735228 · Full text
Individual repeatable variation in behaviour, that is 'personality', is hypothesised to mediate how animals respond to environmental stress. However, temporal variability in local conditions and spatial constraints acros...
Individual repeatable variation in behaviour, that is 'personality', is hypothesised to mediate how animals respond to environmental stress. However, temporal variability in local conditions and spatial constraints across the annual cycle may affect individual responses to environmental change and the subsequent impact on fitness. Here we tested how the relationships among personality, stress exposures and fitness may vary between the breeding and wintering periods in the black-legged kittiwake (Rissa tridactyla), a long-lived migratory seabird inhabiting the rapidly changing Arctic. We conducted a long-term (2013-2021) study to explore how personality, represented by boldness, was related to feather corticosterone (fCORT), an indicator of stress exposure during feather growth. To examine temporal variation in this relationship, we focused on feathers grown during the breeding, post-breeding and pre-breeding stages, three periods when seabirds experience varying spatial constraints. We studied the covariation in fCORT, boldness and two fitness measures (chick survival and adult return rates) while correcting for two major proxies of resource availability: the subpolar gyre and Atlantic water influx (AWI) We observed a season-dependent effect of boldness: 'bolder' individuals had lower fCORT concentrations than 'shyer' conspecifics during breeding and post-breeding but higher levels prior to breeding. Higher fCORT during breeding occurred during years of low AWI and correlated with lower chick survival, while higher fCORT prior to breeding correlated with lower likelihood of return to the colony. Personality did not mediate inter-annual relationships between fCORT and environmental measures or fCORT and fitness. Our results highlight that while the negative effects of environmentally induced stress on fitness appeared to be ubiquitous across personality types, how and when bold and shy individuals experience stress is highly context dependent, reflecting different spatial and temporal constraints during the breeding and wintering stages.
Prey depletion by a predator guild suggests spatial differences in competitive ability, but not prey partitioning, consistent with functional trade-offs.
Wright AN, Edwards KF, Alascio SD … +1 more , Carranza JA
J Anim Ecol · 2026 May · PMID 41709365 · Publisher ↗
Understanding the mechanisms by which competing species coexist is fundamental for explaining the distribution and abundance of organisms. Many coexistence mechanisms require trade-offs in the ability to deplete shared r...
Understanding the mechanisms by which competing species coexist is fundamental for explaining the distribution and abundance of organisms. Many coexistence mechanisms require trade-offs in the ability to deplete shared resources, but resource depletion by competing species is rarely measured, especially in communities of mobile predators. Among competing predators, differences in diet and habitat use are commonly observed, and to promote coexistence, these differences must be associated with trade-offs in the ability to suppress different prey types (prey partitioning) or to suppress prey in different habitats (spatial differences in competitive ability), respectively. We hypothesize that these two mechanisms are important for competition among three arboreal lizards common in Hawaii. We test these mechanisms using experimental monocultures to measure prey suppression and a consumer-resource model parameterized with trait and demographic data from the same experiment. We found that species differed in spatial patterns of prey suppression, supporting spatial differences in competitive ability, but species did not differ in which prey taxa they suppressed, providing no support for prey partitioning. Patterns of prey suppression were consistent with differences between species in microhabitat-specific attack rates, and including differences in the conversion of prey into offspring allowed model outcomes to better align with species' relative prey suppression. When using the model to predict competitive outcomes, Phelsuma laticauda and Anolis sagrei are expected to coexist over a wide range of microhabitat availabilities, Anolis carolinensis can coexist with P. laticauda under a wider range of microhabitat availabilities than it can with A. sagrei, and A. carolinensis cannot persist in the presence of both of the other species under any conditions. These predictions are consistent with the change in community composition that has occurred over time in the field: Anolis carolinensis has declined while the other two species have increased in distribution and abundance. Our results also demonstrate that differences in diet do not necessarily translate into resource partitioning of prey, highlighting the importance of measuring resource depletion when understanding exploitation competition.
Functional response predicts invasiveness but not trophic impact.
Courtois MA, Souques C, Voituron Y … +3 more , Teulier L, Médoc V, Dechaume-Moncharmont FX
J Anim Ecol · 2026 May · PMID 41699788 · Full text
Biological invasions are a major driver of biodiversity erosion mainly because invasive species show greater trophic impact than their non-invasive counterparts. The experimental paradigm for assessing this trophic impac...
Biological invasions are a major driver of biodiversity erosion mainly because invasive species show greater trophic impact than their non-invasive counterparts. The experimental paradigm for assessing this trophic impact is the functional response (FR) test that describes the relationship between per capita consumption rate and resource density. Two key parameters are then assessable and comparable between populations and species: the space clearance rate (attack rate, a) measuring predatory efficiency at low prey densities, and handling time (h) representing the time required to capture, handle and digest prey. This test is frequently conducted to compare non-invasive and invasive species and shows that invasive species have a higher FR than non-invasive species (characterized by higher space clearance rates and lower handling times) which would explain both their invasion success and their ecological impact. However, it appears that whether FR parameters differ between invasive species sampled in their native versus invasion range has never been tested, implicitly assuming that FR measures can be extrapolated to the entire range of distribution. Using a phylogenetically corrected comparative analysis of 269 FR observations from 45 freshwater fish species (23 non-invasive species and 22 invasive species), we confirm that invasive species exhibited higher FR than non-invasive species. However, this pattern holds true only when considering invasive species sampled in their native range. Invasive species studied in their invasion range displayed functional responses comparable to non-invasive species, with similar space clearance rates and handling times. Additionally, space clearance rates decreased with temperature in non-invasive species but tended to increase in invasive species from invasive introduction ranges, suggesting that climate warming may exacerbate competitive asymmetries. Together, these results indicate that high FR predispose species to invasiveness, but also challenge the assumption that FRs measured in the native range of a species can be directly extrapolated to predict its trophic impacts elsewhere. Our findings call for greater consideration of biogeographic context when using functional responses to assess invasion risk and ecological impact.
Herbivore and mesocarnivore carcasses trigger divergent short-term changes in soil properties.
Colino-Barea A, García-Orenes F, Morales-Reyes Z … +13 more , Gonzálvez M, Martínez-Carrasco C, Moleón M, Redondo-Gómez D, Marks EAN, García-Carmona M, Arcenegui V, Huerta-Del-Bosque JC, Orihuela-Torres A, Soliveres S, Albolafio S, Sebastián-González E, Sánchez-Zapata JA
J Anim Ecol · 2026 Feb · PMID 41668264 · Publisher ↗
Animal corpses act as pulses of organic matter (OM) and serve a key zoogeochemical role by providing localized nutrient inputs to soils and thereby contributing to maintaining soil functions and biogeochemical cycles. Am...
Animal corpses act as pulses of organic matter (OM) and serve a key zoogeochemical role by providing localized nutrient inputs to soils and thereby contributing to maintaining soil functions and biogeochemical cycles. Among mammals, carnivore carcasses tend to persist longer than those of herbivores due to lower consumption rates from vertebrate scavengers. This, combined with the different composition and size of carnivore and herbivore carcasses, could modify the effects of animal-derived OM input on soil dynamics. We examined changes in soil properties (pH, electrical conductivity [EC], organic carbon, aggregate stability (AS), microbial respiration and enzymatic activities) driven by the deployment of 20 red fox (Vulpes vulpes: mesocarnivore) and 19 aoudad (Ammotragus lervia: herbivore) carcasses. We also monitored their consumption with camera traps and assessed the modulating effect of scavenging patterns and carrion features (size, type: herbivore vs. mesocarnivore). Carrion increased EC, phosphorus availability and microbial activity in the soil, but had little effect on soil organic carbon or pH. These effects were modulated by carcass size, type (fox or aoudad) and its associated consumption by scavengers. Additionally, scavenger richness modulated the effects of carrion on soil AS and phosphatase. Due to lower carcass weight, longer persistence in the environment, and the interactions between vertebrate scavengers and the carcass, soils below mesocarnivore carcasses featured an enhanced increase in biochemical soil properties, suggesting wider changes in soil microbiological communities as compared to herbivore carcasses. Through contrasting scavenger assemblages and consumption patterns, mesocarnivore and herbivore carcasses play distinct yet equally relevant roles in nutrient-limited dryland soils.
Mobile consumers influence the shoreward edge of intertidal seagrass ecosystems.
Valdez SR, Smith CS, Brenner CL … +2 more , Paxton AB, Silliman BR
J Anim Ecol · 2026 Feb · PMID 41665189 · Publisher ↗
Habitat edges are often considered environmentally stressful areas, and as such, research has largely focused on the impacts of physical factors in shaping these edges. However, less is known about the relative importanc...
Habitat edges are often considered environmentally stressful areas, and as such, research has largely focused on the impacts of physical factors in shaping these edges. However, less is known about the relative importance of biotic disturbance agents and bottom-up drivers in shaping habitat edges. Here, we used intertidal seagrass beds as a model system to test how the independent and combined effects of stingrays-a disturbance-generating forager in seagrass beds-and nutrient addition affect the upper elevation edge of seagrasses. A two-season long manipulative experiment with stingray exclusion × nutrient addition revealed that shoreward seagrass edges experienced heightened loss in percent cover when exposed to stingrays (p = 0.037) but were not impacted by nutrient additions to marine sediments (p = 0.13). Additionally, transplant experiments designed to test whether stingrays could limit intertidal seagrass establishment in higher elevation found that transplanted seagrass had a higher chance of survival when stingrays were excluded (p < 0.01), suggesting that seagrass could live higher in the intertidal and that stingrays may limit shoreward expansion. Finally, a multi-site observational survey demonstrated that stingray pit abundance was a strong predictor of the distance between seagrass edge and shoreward habitats. Combined, these results challenge current understanding in plant ecology that seagrass edges are controlled mainly by physical factors and instead suggest that the structure of the seagrass shoreward edge is controlled by both physical and biotic drivers. Our results also indicate that the relative effects of consumer disturbance and physical factors in controlling edge limits are likely predicated on consumer density: in areas with higher densities of large consumers, biotic forcing is likely to be more important. Furthermore, these results could have implications for restoration in areas with high densities of disturbance-generating foragers and align with calls for greater inclusion of animal impacts into restoration schemes. Biotic drivers along environmentally stressful edges are likely not limited to seagrasses and the generality of biotic control of habitat edges deserves further exploration across diverse ecosystems.
Spatial overlap and temporal synchrony between guilds of insect hosts and parasitoids.
van Dijk LJA, Goodsell RM, Andersson AF … +8 more , Fisher BL, Iwaszkiewicz-Eggebrecht E, Lukasik P, Miraldo A, Peña-Aguilera P, Ronquist F, Roslin T, Tack AJM
J Anim Ecol · 2026 Apr · PMID 41665095 · Full text
How communities are structured into functional groups and trophic layers is key to understanding ecosystem functioning. Nonetheless, we lack insights about spatiotemporal variation in guild composition of communities and...
How communities are structured into functional groups and trophic layers is key to understanding ecosystem functioning. Nonetheless, we lack insights about spatiotemporal variation in guild composition of communities and its causes. To investigate spatial and temporal patterns and drivers of variation in insect feeding guilds, we combined data from a nationwide survey of Swedish insects using Malaise traps and DNA metabarcoding with a comprehensive trait database. We assigned species into one of three feeding guilds (phytophages, saprophages, predators) or into one of three associated parasitoid guilds. We then analysed patterns in species richness for each guild. Species richness declined with latitude in all guilds. Beyond this gradient, local variation in species richness matched between hosts and their parasitoids. Yet, hosts and their parasitoids responded differently to habitat. The phenological peak of parasitoid species richness appeared later than the peak of their hosts, but the length of time lags varied among guilds. Spatiotemporal patterns were driven by guild-specific responses to temperature, though much variation remained between seasons and locations even when controlling for temperature. Overall, these patterns suggest that shifts in both climate and land use may alter the synchrony of insect trophic layers, with unknown consequences.
From crisis to partial recovery: Demographic changes in female Alpine ibex following a pneumonia outbreak.
Bonsacquet L, Besnard A, Cavailhes J … +1 more , Garel M
J Anim Ecol · 2026 Apr · PMID 41664357 · Publisher ↗
Epizootics can profoundly impact population dynamics, affecting both survival and reproduction over relatively short periods. However, the longer-term demographic patterns that may follow an outbreak, as well as the unde...
Epizootics can profoundly impact population dynamics, affecting both survival and reproduction over relatively short periods. However, the longer-term demographic patterns that may follow an outbreak, as well as the underlying mechanisms, remain poorly documented. To investigate these dynamics, we compared the demographic parameters of females in an Alpine ibex population before (10 years), during (2 years) and after (two subsequent 7-year periods) a severe pneumonia outbreak. Using an integrated population model combining female capture-mark-recapture and census data, and accounting for individual heterogeneity, we estimated the age-specific breeding probability, survival and female population growth rate. We observed an increase in breeding probability after the epizootic, rising from pre-epizootic values of 0.63 to over 0.79 in high-quality females and from 0.03 to over 0.24 in low-quality females that had not bred the previous year. The age of primiparity decreased for most females, and while high-quality females that had previously reproduced were less likely to reproduce again compared to non-reproductive females before the epizootic, the opposite pattern was observed after the epizootic. These findings are consistent with the expected reduced impact of density-dependent processes following the 62% decline in female population size during the epizootic, which affected female survival across all age categories, except for prime-age non-reproductive individuals. This greater reproductive investment contrasted with a decline in survival, which was 6.7% lower for two-thirds of the adult female population (and 2% lower for the entire adult female population) during all post-epizootic periods. The persistent presence of the pathogen in the population, potentially indicating chronic or latent infection, combined with recent environmental changes (e.g. warmer conditions), may have prevented adult survival from returning to pre-epizootic levels. This sustained shortfall in adult survival compared to pre-epizootic levels resulted in a weak post-epizootic recovery of the population (+2.4% year) driven only by high-quality females. These findings illustrate that long-term monitoring populations during adverse environmental conditions, such as disease outbreaks, can provide insights into how long-lived iteroparous females navigate survival-reproduction trade-offs in response to pathogen exposure and access to resources. This can help anticipate demographic responses to emerging infectious diseases and climate change.
Long-term trends of epibionts reflect Mediterranean striped dolphin abundance shifts caused by morbillivirus epidemics.
Ten S, Dupont G, Raga JA … +2 more , Dobson AP, Aznar FJ
J Anim Ecol · 2026 Mar · PMID 41649039 · Full text
Since 1990, Mediterranean striped dolphins, Stenella coeruleoalba, have suffered two mass mortality events caused by the dolphin morbillivirus (DMV), but the population-level impact is unknown because abundance estimates...
Since 1990, Mediterranean striped dolphins, Stenella coeruleoalba, have suffered two mass mortality events caused by the dolphin morbillivirus (DMV), but the population-level impact is unknown because abundance estimates are spatio-temporally sparse. This study investigates whether data from epibionts of striped dolphins-the barnacle Xenobalanus globicipitis, the cyamid Syncyamus aequus, and the copepod Pennella balaenoptera, with different life cycles and degrees of specificity-could provide indirect evidence on host population dynamics. To address this question, we combined empirical and theoretical approaches. First, we used Generalized Additive Models (GAMs) to examine occurrence trends of the three epibiotic species over the period 1980-2023 for both striped dolphins and other sympatric cetacean species that did not suffer DMV outbreaks. Second, we developed a two-step theoretical modeling approach to investigate the epidemiology of these DMV outbreaks (SIR model) and to link dolphin population abundance shifts with the epibiont trends observed empirically (mechanistic model). The SIR model provided coarse estimates of the impact of DMV on the striped dolphin population under two scenarios with varying virus-induced mortality and duration of the infectious period. These estimates were then used to simulate the effect of dolphin population shifts on its epibionts through mechanistic models. Models indicated that DMV-induced shifts in striped dolphin population dynamics have cascading effects on the population abundance of X. globicipitis and S. aequus, whereas the population of the less host-specific P. balaenoptera was unaffected. Together, long-term trends in the occurrence of host-specific epibionts can serve as an indicator of host abundance shifts.
Generation cycles in experimental populations of a multivoltine insect.
Yamanaka T, Sato Y, Nelson WA … +1 more , Bjørnstad ON
J Anim Ecol · 2026 May · PMID 41636277 · Full text
Some animals exhibit large-amplitude fluctuations with periods close to their generation length. These fluctuations can be caused by seasonal environmental influences, scheduled pesticide applications, or ecological fact...
Some animals exhibit large-amplitude fluctuations with periods close to their generation length. These fluctuations can be caused by seasonal environmental influences, scheduled pesticide applications, or ecological factors such as intraspecific regulation and consumer-resource interactions. While theory provides various mechanisms for how environmental and ecological factors might generate generational fluctuations, there has never been a field experiment testing the relative contributions of seasonal demographic synchronisation and intraspecific regulation to generation cycles in natural populations. The smaller tea tortrix, Adoxophyes honmai, is a serious pest of tea plants and a temperate multivoltine insect that undergoes 3-5 large-amplitude generation cycles each year under natural conditions in Japan. Theory suggests that these fluctuations may represent limit cycles driven by asymmetric intraspecific interference, where older larvae directly affect younger ones. However, in the field, these populations also experience strong seasonality and periodic insecticide applications that are thought to either generate or modify these fluctuations. We conducted a replicated field-cage experiment on the tortrix populations to manipulate the initial degree of stage synchrony and the timing of introduction. The experiment included four treatments contrasting pulsed versus continuous age structures at the onset of spring, along with two introduction timings separated by 20 days (approximately half a generation time). We minimised artificial interventions, such as harvesting and insecticide application, as well as the effect of natural enemies while allowing meteorological influences during the season. To compare the field-cage experiment results with theoretical predictions, we constructed an age-structured population model featuring asymmetric larval interference. We executed simulations using the same introduction scenarios as in the field-cage experiment. We observed the emergence of clear generational cycles in all treatments of the field-cage even in the absence of any initial demographic synchrony. This suggests an internal mechanism regulating population cycles, possibly intraspecific interference. However, the generational cycles in the field-cage were synchronised across treatments and with outer field populations. The results from the field-cage experiment and simulation analyses indicate that external environmental factors, such as precipitation, acted as a pacemaker for the generational cycles created by the internal regulatory mechanism.
Global determinants of home range sizes in felids: Evidence of human disturbance impact.
Moraru A, Anile S, Devillard S
J Anim Ecol · 2026 Apr · PMID 41636274 · Full text
Home range (HR) is a key indicator of animal spatial ecology. HR size, shape, location and habitat composition reflect both species' ecological requirements and their responses to anthropogenic stressors. Felidae, a char...
Home range (HR) is a key indicator of animal spatial ecology. HR size, shape, location and habitat composition reflect both species' ecological requirements and their responses to anthropogenic stressors. Felidae, a charismatic taxon, faces escalating threats mainly due to habitat degradation and human-wildlife conflict. Understanding the ecological and anthropogenic drivers of HR size variation is therefore critical for their conservation. To address this gap and explore these factors at a global scale for the entire taxon, we used the HomeRange database-a global database with HR values across 960 different mammal species-complemented with about 20% additional records, to compile 1137 individual HR size estimates from 29 out of 40 recognized wild felid species. We applied generalized linear mixed models to assess the influence of intrinsic, methodological, ecological and anthropogenic factors on space use. HR size was shaped by multiple drivers. It increased with body mass (0.94 ± 0.16; p < 10) and was larger in males than in females (0.51 ± 0.07; p < 10), consistent with higher energy demands and sex-specific reproductive strategies. HR size decreased with increasing productivity (-0.37 ± 0.07; p < 10) and felid richness (-0.24 ± 0.10; p = 0.02), suggesting reduced spatial requirements in resource-rich areas and under interspecific competition. HR size also decreased with increasing croplands (HR: -0.50 ± 0.14; p < 10) and pastures (HR: -0.16 ± 0.07; p = 0.02)-both human footprint proxies-which may reflect multiple causes such as anthropogenic food sources, habitat loss or movement restriction from infrastructures associated with agriculture. Our results reinforce the role of well-known established HR size's predictors such as body mass, sex and primary productivity while highlighting the impact of less frequently investigated factors (i.e. felid richness and agricultural land-use). Our findings emphasize the importance of incorporating a broad range of biological, environmental and methodological predictors when studying space use across a taxonomic group. Our approach provides novel insights into habitat requirements and the effects of anthropogenic pressures, which can ultimately lead to improved conservation strategies for felids.
Demographic buffering in natural populations: A multi-level perspective.
Santos GS, Gascoigne SJL, Dias ATC … +2 more , Kajin M, Salguero-Gómez R
J Anim Ecol · 2026 Feb · PMID 41631607 · Publisher ↗
Environmental stochasticity poses significant challenges to population persistence. A key mechanism thought to buffer populations against such variability is demographic buffering-the ability of a population to stabilise...
Environmental stochasticity poses significant challenges to population persistence. A key mechanism thought to buffer populations against such variability is demographic buffering-the ability of a population to stabilise growth despite temporal fluctuations in survival, development or reproduction. However, empirical tests of demographic buffering remain limited and often yield conflicting results. Here, we propose an integrative demographic framework that combines two complementary approaches to identify demographic buffering: (1) stochastic elasticities, which quantify the sensitivity of long-term stochastic growth rates (λ) to variance in demographic processes, and (2) second-order derivatives of deterministic growth (λ₁), which indicate whether selection acts to reduce or amplify variance in vital rates. Applying this framework to 43 natural populations across 37 mammalian species, we position each species along a variance continuum and assess whether those with low stochastic elasticities-suggestive of buffering-also exhibit signs of concave selection on key demographic processes. While most primates and a few other long-lived mammals occupy the buffered end of the continuum, only one species-the Columbian ground squirrel-exhibits strong support for our hypothesis, with key vital rates both critical for λ₁ and under concave selection. In contrast, primates, despite showing low stochastic elasticities, often show convex or absent second-order effects on their most influential vital rates, indicating a mismatch between ecological buffering and evolutionary constraint. Our findings suggest that demographic buffering is more dynamic and context dependent than previously recognised. Selection does not consistently act to reduce variance in key demographic processes, even in species where population growth appears robust to environmental variability. This decoupling implies that evolutionary and ecological signals of buffering may not always align. Our framework offers a new lens to dissect the demographic and selective processes underpinning resilience, providing a scalable tool for exploring demographic strategies across taxa. Future work integrating phylogenetic context, trait covariation and environmental drivers will be essential to understand the adaptive value of demographic buffering under global change.
Hormonal plasticity to food restriction is heritable in the house sparrow, Passer domesticus.
Ouyang JQ, Lendvai ÁZ
J Anim Ecol · 2026 Apr · PMID 41630174 · Publisher ↗
Theoretical and empirical studies agree that populations harbour extensive among-individual variation in phenotypic plasticity, but the mechanisms generating and maintaining this variation are often unknown. Endocrine sy...
Theoretical and empirical studies agree that populations harbour extensive among-individual variation in phenotypic plasticity, but the mechanisms generating and maintaining this variation are often unknown. Endocrine systems, which can change plastically in response to environmental variation, may be shaped by natural selection, but their evolution requires heritable variation. It is currently unknown if endocrine plasticity in response to environmental challenges is heritable. We investigated this question in house sparrows, Passer domesticus, by testing glucocorticoid responsiveness to food restriction. We alternated restricted (70% of individual daily food intake) and adequate (110%) treatments twice, drawing blood samples at the end of each treatment. Based on glucocorticoid responsiveness, we classified individuals into high-plasticity, low-plasticity and medium (control) groups by selecting the 20 most responsive, least responsive and random individuals, respectively. We transferred these groups into separate aviaries and let them reproduce. In the next generation, we measured hormonal responsiveness using identical methods. Using a cross-foster design and quantitative genetic models, we partitioned the heritability of glucocorticoid responsiveness into genetic and environmental components. We found moderate heritability (h > 30%) of glucocorticoid plasticity in response to food availability. The environmental and residual variances of glucocorticoid responsiveness were smaller than those for the intercept. Our findings provide empirical evidence for the existence of heritable individual variation in glucocorticoid plasticity, highlighting its potential to evolve under natural selection, particularly in dynamic and rapidly changing environments.
Cohorts of immature Pteropus bats show interannual variation in Hendra virus serology.
Crowley DE, Falvo CA, Grant CK … +22 more , Borremans B, Lunn TJ, Ruiz-Aravena M, Benson E, McKee CD, Becker DJ, Jones DN, Bushmaker T, Yu YT, Michie M, Dale AS, Yan L, Sterling SL, Broder CC, Goodman LB, Petraityte-Burneikiene R, Laing ED, Smith IL, Munster VJ, Rynda-Apple A, Peel AJ, Plowright R
J Anim Ecol · 2026 Mar · PMID 41622695 · Full text
Understanding the drivers of seasonal disease outbreaks remains a fundamental challenge in disease ecology. Periodic outbreaks can be driven by several seasonally varying factors, including pulses of susceptible individu...
Understanding the drivers of seasonal disease outbreaks remains a fundamental challenge in disease ecology. Periodic outbreaks can be driven by several seasonally varying factors, including pulses of susceptible individuals through births, changes in host behaviour and social aggregation and variation in host immunity. However, when these potential drivers overlap temporally, isolating their relative contributions to outbreak patterns becomes challenging. We studied Hendra virus, a zoonotic pathogen with seasonal spillovers from bats to horses and humans. Multiple seasonal factors have been hypothesized to drive Hendra virus transmission, including food shortages, birth pulses and changes in host aggregation, but their temporal overlap has made identifying primary drivers difficult. We conducted a 4-year longitudinal study of Pteropus bats to test whether seasonal birth pulses and the resulting influx of susceptible juveniles drive Hendra virus transmission. Using a Bayesian ageing model, we aged sexually immature bats and placed them into birth cohorts. We used our age predictions to model how viral shedding and antibody responses changed as bats aged. We tracked Bartonella spp. Infection-a bacterial pathogen requiring close contact for transmission-as an indicator of transmission opportunities within each cohort for comparison. We found no evidence that seasonal birth pulses of immunologically naïve juveniles drove Hendra virus transmission. Two out of three cohorts showed substantially reduced maternal antibody transfer compared to the 2018 cohort, with seroprevalence near zero at our earliest sampling timepoints and showed no clear evidence of synchronized seroconversion. Furthermore, Bartonella infection rates were consistent across cohorts, indicating that opportunities for pathogen transmission remained consistent across cohorts despite varying viral shedding patterns. Our findings demonstrate that birth pulses alone cannot explain observed patterns of Hendra virus outbreaks. These results highlight the importance of using multiple lines of evidence to evaluate competing mechanisms underlying seasonal disease dynamics, particularly when potential drivers coincide temporally.
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