Large Herbivores Research Articles

The interacting effect of climate change and herbivory can trigger large-scale transformations of European temperate forests.

In many regions of Europe, large wild herbivores alter forest community composition through their foraging preferences, hinder the forest's natural adaptive responses to climate change, and reduce ecosystem resilience. We investigated a widespread European forest type, a mixed forest dominated by Picea abies, which has recently experienced an unprecedented level of disturbance across the continent. Using the forest landscape model iLand, we investigated the combined effect of climate change and herbivory on forest structure, composition, and carbon and identified conditions leading to ecosystem transitions on a 300-year timescale. Eight climate change scenarios, driven by Representative Concentration Pathways 4.5 and 8.5, combined with three levels of regeneration browsing, were tested. We found that the persistence of the current level of browsing pressure impedes adaptive changes in community composition and sustains the presence of the vulnerable yet less palatable P. abies. These development trajectories were tortuous, characterized by a high disturbance intensity. On the contrary, reduced herbivory initiated a transformation towards the naturally dominant broadleaved species that was associated with an increased forest carbon and a considerably reduced disturbance. The conditions of RCP4.5 combined with high and moderate browsing levels preserved the forest within its reference range of variability, defining the actual boundaries of resilience. The remaining combinations of browsing and climate change led to ecosystem transitions. Under RCP4.5 with browsing effects excluded, the new equilibrium conditions were achieved within 120 years, whereas the stabilization was delayed by 50-100 years under RCP8.5 with higher browsing intensities. We conclude that forests dominated by P. abies are prone to transitions driven by climate change. However, reducing herbivory can set the forest on a stable and predictable trajectory, whereas sustaining the current browsing levels can lead to heightened disturbance activity, extended transition times, and high variability in the target conditions.

Linking small mammal capture probability with understory structural complexity using a mobile laser scanning‐derived metric: A case study

AbstractForest understory complexity is important for many species, from large herbivores such as deer to small mammals such as mice and voles. For species that utilize the forest understory on a very small scale, it is often impractical to conduct correspondingly fine‐grained manual surveys of the understory, and thus few studies consider this small‐scale variation in understory complexity and instead work with average values on a larger scale. We explored the use of a mobile laser scanning derived understory complexity measure—understory roughness—to predict the capture probability of two representative small mammal species, the yellow‐necked mouse (Apodemus flavicollis) and the bank vole (Clethrionomys glareolus). We found a positive relationship between capture probability and understory roughness for both bank voles and yellow‐necked mice. Our results suggest that mobile laser scanning is a promising technology for measuring understory complexity in an ecologically meaningful way.

Does restoring apex predators to food webs restore ecosystems? Large carnivores in Yellowstone as a model system

AbstractModification of food webs is a frequent cause of shifts in ecosystem states that resist reversal when the food web is restored to its original condition. We used the restoration of the large carnivore guild including gray wolves (Canis lupis), cougars (Felis concolor), and grizzly bears (Ursus arctos horribilis) to the northern range of Yellowstone National Park as a model system to understand how ecosystems might resist reconfiguration after the restoration of apex predators to the food web. The absence of wolves, cougars, and grizzly bears for nearly a century from the northern range was the primary cause of dramatic changes in riparian plant communities. Willows (Salix spp.) were suppressed in height by intense browsing by the dominant herbivore, elk (Cervus canadensis). The loss of activity by beavers (Castor canadensis) coincided with the loss of tall willows. We hypothesized that intense elk browsing interrupted the mutualism between willow and beavers: ecosystem engineering by beavers was a critical component of willow habitat and tall willows were a critical component of habitat for beavers. This interruption made riparian communities resilient to the disturbance caused by the restoration of apex predators. We hypothesized further that reductions in elk browsing attributable to reductions in elk population size were not sufficient to prevent the suppression of willow growth. To test these hypotheses, we conducted a 20‐year, factorial experiment that crossed simulated beaver dams with the exclusion of browsing. We found that willows grew to heights expected for restored communities only in the presence of dams and reduced browsing. Willows experiencing ambient conditions remained well below this expectation. We found no difference in heights or growth rates of willows in experimental controls and willows in 21 randomly chosen sites, confirming that the results of the experiment were representative of range‐wide conditions. A reorganized community of large herbivores was implicated in the suppression of willow growth. We conclude that the restoration of large carnivores to the food web failed to restore riparian plant communities on Yellowstone's northern range, supporting the hypothesis that this ecosystem is in an alternative stable state caused primarily by the extirpation of apex predators during the early 20th century.

Effects of temperament during handling and social rank on the blood biochemical parameters of common eland (Taurotragus oryx)

Large herbivores are subject to handling and social stress in captivity. These may affect blood biochemical values, which motivated this research. Twelve healthy common eland (Taurotragus oryx) were monitored for 12 months. The animals were handled monthly, and blood samples were collected. Samples from every second month were analysed for 14 blood biochemical parameters. Temperament throughout the handling, as the summation of various behavioural responses, was calculated as a proxy of the stress generated during handling. Social behaviour was recorded each month, and the agonistic interactions were used to calculate the social rank, which was considered a proxy of social stress. Generalised Linear Mixed Models were designed to test the effects of temperament and social rank on the blood biochemical parameters while keeping sex, age, body condition, and body weight as covariates. The results show that the temperament during handling influences blood levels of albumin, alkaline phosphate, blood urea nitrogen, glucose, total bilirubin, and total protein; however, social rank has little influence, affecting just albumin. The ranges observed in the values of these biochemical parameters were still within their reference intervals, implying the absence of pathology or physiological problems during the study. The results suggest that blood biochemical values of physically restrained common eland should be carefully interpreted, even in animals already habituated to routine handling. On the contrary, social rank has low effects on the blood biochemical parameters.

Specialist carabids in mixed montane forests are positively associated with biodiversity-oriented forestry and abundance of roe deer

The ongoing transition within forest management towards more biodiversity-oriented practices, such as close-to-nature forestry and retention forestry, may benefit forest fauna such as forest-specialized ground beetles (Coleoptera: Carabidae). However, it remains unclear how forest carabids are jointly affected by these practices in Central European montane forests, which host particularly sensitive, range-restricted carabid species, and where biodiversity-oriented forestry is widely applied. Moreover, roe deer (Capreolus capreolus), the most common large herbivore in these forests, is intensively managed to reduce browsing pressure, but it is yet unknown how this may affect carabids, alongside the effect of silviculture. On 66 1-ha plots in the Black Forest region of Germany, we sampled carabids with pitfall traps, measured roe deer abundances using camera trapping, and measured several structural variables directly related to close-to-nature and retention practices, as well as variables describing microclimate and landscape-level forest cover. We found that the carabid assemblage was dominated by forest specialists, with little influence from fragmentation of the surrounding forest. Higher broadleaf share (and canopy cover for montane specialists) was correlated with higher carabid activity-density. Increasing stand maturity (and lying deadwood volume for montane specialists), was correlated with higher species richness. Plots with higher roe deer abundances showed higher carabid richness and activity-density. Assemblage composition changed along the altitudinal gradient, and both richness and activity-density increased with elevation. Thus, carabid communities, including montane specialists and several species of conservation interest, stand to benefit from close-to-nature and retention practices, if applied throughout the altitude range of montane forests. Forest carabids may additionally profit from maintaining higher roe deer abundances, but further research is needed to understand this causal link, as well as to weigh the costs and benefits of deer culling for forest biodiversity.

C and N stable isotopes enlighten the trophic behaviour of the dugong (Dugong dugon)

The dugong (Dugong dugon), a large marine mammal herbivore of the Indo-Pacific, is vulnerable to extinction at a global scale due to a combination of human-related threats including habitat degradation. The species forages on seagrass habitats (marine phanerogams) and plays a key role in the functioning and sensitivity of these declining coastal ecosystems. The trophic behaviour and plasticity of dugong populations in response to extrinsic and intrinsic factors are therefore crucial features to both dugong and seagrass conservation. Yet, this knowledge remains limited to few visual observations and analyses of mouth, stomach or faecal contents of stranded individuals. We take advantage of a long-term monitoring of stranded individuals from the endangered New Caledonian population to depict features of dugongs’ trophic ecology from Carbon and Nitrogen stable isotopes. A total of 59 dugong skin samples were used to portrait the stable isotope niche of dugongs according to their sex and maturity. In light of previous work conducted in New Caledonia, a subset of these samples was used to model the trophic mix of dugong males and females. Our stable isotope mixing models used C and N isotope values of 10 taxa bbelonging to five divisions of metazoans, plants, and chromists. Our results represent the first estimate of the species dietary niche in the isotopic space. They suggest that the diet of dugong calves overlaps more with that of adult females (δ13C: − 6.38 ± 1.13 ‰; δ15N: 2.49 ± 1.10 ‰) than males (δ13C: − 5.92 ± 1.10 ‰; δ15N: 3.69 ± 1.28 ‰). Further, we highlight differences in the expected trophic mix of dugong adult males and females. From these, we formulate a sex-specific foraging behaviour hypothesis in dugongs, whereby lactating females could forage over smaller spatial ranges but more diverse food sources thanmales. The study emphasizes the importance of long-term stranding monitoring programs to study the ecology of marine mammals.. Finally, it depicts an ecological feature that may contribute to the sensitivity of vulnerable dugongs to ongoing changes on tropical coastal ecosystems.

Regional‐scale effects of deer‐induced forest degradation on river ecosystem dynamics

AbstractAlmost all ecosystems are open systems, meaning that significant changes in one ecosystem can lead to unexpected changes in others. Deer overabundance has become a problem worldwide, leading to forest degradation that has impacts on not only terrestrial, but also aquatic ecosystems. This study aims to investigate the regional‐scale importance of large herbivores in inter‐ecosystem interactions by examining the effects of deer‐induced forest degradation on fish populations. We selected similar‐scale catchments from river systems in Hyogo, Japan, that differed in the time since deer‐induced forest degradation. Conventional surveys for fish densities and microhabitat environments were conducted in 23 catchments, and surveys using quantitative eDNA metabarcoding were conducted in 95 catchments. We examined the relationships between fish population densities, microhabitats, and time since forest degradation, considering confounding effects. Data from 8 and 17 fish taxa detected by snorkeling and eDNA methods, respectively, were available for statistical analysis. Snorkeling‐counts (Individuals/1 m transect) and eDNA concentrations (Copies/L) in river water were strongly correlated. Fine sediments on riverbeds were increased in the 3–15 years following forest degradation and decreased after 16 years. Population densities of sand‐preferring fishes, as inferred from both eDNA and snorkeling, reasonably followed this pattern. These patterns may be caused by the depletion of fine sediments on mountain slopes. The results of this study suggest that deer‐induced worldwide alternation may also occur in aquatic ecosystems.

Genetic approaches reveal a healthy population and an unexpectedly recent origin for an isolated desert spring fish

Foskett Spring in Oregon’s desert harbors a historically threatened population of Western Speckled Dace (Rhinichthys klamathensis). Though recently delisted, the dace’s recruitment depends upon regular removal of encroaching vegetation. Previous studies assumed that Foskett Dace separated from others in the Warner Valley about 10,000 years ago, thereby framing an enigma about the population’s surprising ability to persist for so long in a tiny habitat easily overrun by plants. To investigate that persistence and the effectiveness of interventions to augment population size, we assessed genetic diversity among daces inhabiting Foskett Spring, a refuge at Dace Spring, and three nearby streams. Analysis revealed a robust effective population size (Ne) of nearly 5000 within Foskett Spring, though Ne in the Dace Spring refuge is just 10% of that value. Heterozygosity is slightly lower than expected based on random mating at all five sites, indicating mild inbreeding, but not at a level of concern. These results confirm the genetic health of Foskett Dace. Unexpectedly, genetic differentiation reveals closer similarity between Foskett Dace and a newly discovered population from Nevada’s Coleman Creek than between Foskett Dace and dace elsewhere in Oregon. Demographic modeling inferred Coleman Creek as the ancestral source of Foskett Dace fewer than 1000 years ago, much more recently than previously suspected and possibly coincident with the arrival of large herbivores whose grazing may have maintained open water suitable for reproduction. These results solve the enigma of persistence by greatly shortening the duration over which Foskett Dace have inhabited their isolated spring.

From meat availability to hominin and carnivore biomass: A paleosynecological approach to reconstructing predator-prey biomass ratios in the Pleistocene

Reconstructing the conditions and circumstances under which the human lineage evolved is of great interest to those disciplines related to human evolution, especially in fields such as archaeoecology and human paleoecology. A mathematical model was presented almost a decade ago aimed to reconstructing the human populations that the Pleistocene paleoecosystems could support. This model followed a paleosynecological perspective, being focused on: (i) estimating the availability of meat resources in the paleoecosystems, as these resources are vital for human survival; and (ii) measuring the level of competition for these resources among the members of the carnivore guild, including hominins. The model has been applied since then to several Pleistocene localities of Europe, with particular emphasis on the Orce and Sierra de Atapuerca sites. In this study, we use the model for estimating predator-prey biomass ratios and compare the model outputs with the values measured in present-day African ecosystems. The results obtained confirm that our paleosynecological approach provides estimates of predator-prey biomass ratios that are broadly similar to those measured in the extant ecosystems. However, our estimates tend to be slightly higher than expected, which is probably due to the weight of species that satisfy part of their nutritional requirements with resources other than the meat from large herbivores. This allows us to assume that our model performs relatively well, although it has room for methodological improvements.

How do predator interference, prey herding and their possible retaliation affect prey-predator coexistence?

<abstract><p>In this paper, focusing on individualistic generalist predators and prey living in herds which coexist in a common area, we propose a generalization of a previous model, namely, a two-population system that accounts for the prey response to predator attacks. In particular, we suggest a new prey-predator interaction term with a denominator of the Beddington-DeAngelis form and a function in the numerator that behaves as $ N $ for small values of $ N $, and as $ N^{\alpha} $ for large values of $ N $, where $ N $ denotes the number of prey. We can take the savanna biome as a reference example, concentrating on large herbivores inhabiting it and some predators that feed on them. Only two conditionally stable equilibrium points have emerged from the model analysis: the predator-only equilibrium and the coexistence one. Transcritical bifurcations from the former to the latter type of equilibrium, as well as saddle-node bifurcations of the coexistence equilibrium have been identified numerically by using MATLAB. In addition, the model was found to exhibit bistability. Bistability is studied by using the MATLAB toolbox bSTAB, paying particular attention to the basin stability values. Comparison of coexistence equilibria with other prey-predator models in the literature essentially shows that, in this case, prey thrive in greater numbers and predators in smaller numbers. The population changes due to parameter variations were found to be significantly less pronounced.</p></abstract>

Interactive effects of moose browsing and stand composition on the development of mixed species seedling stands

The moose (Alces alces L.), a common large herbivore in the boreal region, impairs forest regeneration by browsing on tree seedlings and saplings. Moose prefer deciduous species, but during winter more coniferous seedlings are used. We used meta-analyses, separately for deciduous and coniferous seedlings, for evaluating whether excluding moose browsing affected seedling density and height. In addition, we compared (1) deciduous seedling proportion, (2) stand density, (3) elapsed time from fencing and (4) estimated moose density with moose exclusion effect sizes. Fencing had a positive effect on coniferous seedling height. With more deciduous trees in a seedling stand, the fencing effect for both seedling height and density of coniferous seedlings decreased. On the other hand, the fencing effects increased with denser stands. At some point effect sizes turned to negative, and conifer species varied in their response to browsing. This implies that deciduous seedlings can protect conifers from browsing by moose up to some mixing ratio, but when deciduous seedling densities are too high, their negative effect increases, presumably through increased competition. Our results suggest that a moderate deciduous admixture in conifer-dominated mixed seedling stands can decrease moose damage but also underline the significance of timely silvicultural measures to minimize the negative effects of excessive deciduous seedlings and too dense stands. Due to differences in coniferous and deciduous species, as well as their compositions and amounts in studied experiments, more studies adjusted to local conditions are still needed to give exact measures for silvicultural recommendations.

Assessing the effect of invasive organisms on forests under information uncertainty: The case of pine wood nematode in continental Europe

Forests worldwide are experiencing increasingly intense biotic disturbances; however, assessing impacts of these disturbances is challenging due to the diverse range of organisms involved and the complex interactions among them. This particularly applies to invasive species, which can greatly alter ecological processes in their invaded territories. Here we focus on the pine wood nematode (PWN, Bursaphelenchus xylophilus), an invasive pathogen that has caused extensive mortality of pines in East Asia and more recently has invaded southern Europe. It is expected to expand its range into continental Europe with heavy impacts possible.Given the unknown dynamics of PWN in continental Europe, we reviewed laboratory and field experiments conducted in Asia and southern Europe to parameterize the main components of PWN biology and host-pathogen interactions in the Biotic Disturbance Engine (BITE), a model designed to implement a variety of forest biotic agents, from fungi to large herbivores. To simulate dynamically changing host availability and conditions, BITE was coupled with the forest landscape model iLand. The potential impacts of introducing PWN were assessed in a Central European forest landscape (40,928 ​ha), likely within PWN’s reach in future decades.A parameter sensitivity analysis indicated a substantial influence of factors related to dispersal, colonization, and vegetation impact, whereas parameters related to population growth manifested a minor effect. Selection of different assumptions about biological processes resulted in differential timing and size of the main mortality wave, eliminating 40%–95% of pine trees within 100 years post-introduction, with a maximum annual carbon loss between 1.3% and 4.2%. PWN-induced tree mortality reduced the Gross Primary Productivity, increased heterotrophic respiration, and generated a distinct legacy sink effect in the recovery period. This assessment has corroborated the ecological plausibility of the simulated dynamics and highlighted the need for new strategies to navigate the substantial uncertainty in the agent’s biology and population dynamics.

Assessment of Nutrients in Natural Saltlicks, Artificial Saltlicks, and General Soils Used by Wild Asian Elephants (Elephas maximus) in the Western Forests of Thailand

Saltlicks are fundamental resources for wild Asian elephants (Elephas maximus). This study aimed to assess the nutrients found in natural saltlicks (NSs) and artificial saltlicks (ASs), as well as general soils (GS) in the natural forest of Salakphra Wildlife Sanctuary (SWS) and a restoration area of Kui Buri National Park (KNP), a which is a forest in Western Thailand. We monitored 33 NSs, 35 ASs, and 20 GSs used by wild Asian elephants. In both areas, the K, Mg, Fe, and Cu in NSs were significantly higher than in ASs. The Ca and Zn in NSs of KNP were lower than the ASs of SWS. The salinity of ASs was the highest, making it significantly higher than that of the NSs in both areas. The ASs can supplement Na, thereby increasing salinity in both areas. The Ca, K, Mg, Fe, and Cu in NSs were significantly higher than in ASs, making them a primary target for elephants. These findings have consequences for conserving elephants and other large herbivores by supplementing essential macro- and micro-nutrients in ASs.

Knowledge and values drive acceptability of lethal control of kangaroos among the Australian public

Wildlife management actions are increasingly contingent on acceptance by the broader public. Consequently, understanding factors that influence acceptability of different management options is important. In Australia, kangaroos (native large herbivores, Macropus spp., Osphranter spp.) are managed using lethal control for a range of context-specific reasons. We surveyed 1293 members of the Australian public to test whether acceptability of lethal control of kangaroos depends on the reason for the control, values towards wildlife (assessed using the Wildlife Values Orientation questionnaire), and knowledge about kangaroos. We also tested whether acceptability could be shifted by providing relevant information. Lethal control of kangaroos for biocentric reasons (i.e., agricultural protection, biodiversity conservation, animal welfare) was more acceptable than lethal control of kangaroos for anthropocentric reasons (i.e., human consumption, human safety). Acceptability was greater among survey respondents high on the domination orientation (i.e., valuing wildlife for human benefits), and lower among those high on the mutualism orientation (i.e., valuing wildlife for its own intrinsic value). Acceptability was also positively associated with knowledge of kangaroo ecology and management. Provision of information did not impact acceptability of lethal control for any reason except for human use, which, while not significant, showed promise that acceptability of lethal control for this reason could be influential to the public. Additionally, while the acceptability of lethal control varied widely among the Australian population, there was little evidence of polarisation, suggesting that large sectors of the public may be amenable to different perspectives.

Short communication: Concentrated impacts by tree canopy drips – hotspots of soil erosion in forests

Abstract. The degradation of ground vegetation cover caused by large grazing herbivores frequently results in enhanced erosion rates in forest ecosystems. Splash erosion can be caused by drop impacts with a high throughfall kinetic energy (TKE) from the tree canopy. Notably larger canopy drips from structurally mediated woody surface points appear to induce even higher TKE and generate concentrated impact locations causing severe focus points of soil erosion. However, TKE at these locations has rarely been reported. This pilot study investigated the intensity of TKE at a concentrated impact location and compared it with general TKE locations under the canopy and freefall kinetic energy (FKE) outside the forest. We measured precipitation, TKE and FKE using splash cups at seven locations under Japanese beech trees and five locations outside the forest during the leafless and leafed seasons in 2021 in a mixed forest with evergreen coniferous trees and deciduous broadleaved trees in Japan. The TKE at the concentrated impact location was 15.2 and 49.7 times higher than that at the general locations under the beech and FKE, respectively. This study confirmed that canopy drip from woody surfaces could be a hotspot of soil erosion in temperate forest ecosystems. Throughfall precipitation at the concentrated impact location was 11.4 and 8.1 times higher than that at general locations and freefall, respectively. TKE per 1 mm precipitation (here, “unit TKE”) at the concentrated impact location (39.2 ± 23.7 J m−2 mm−1) was much higher than that at general locations (22.0 ± 12.7 J m−2 mm−1) and unit FKE (4.5 ± 3.5 J m−2 mm−1). Unit TKE in the leafless season was significantly lower than in the leafed season because of fewer redistribution of canopy drips induced only by woody tissue. Nevertheless, unit TKE at the concentrated impact location in the leafless season (36.4 J m−2 mm−1) was still higher than at general locations in the leafed season. These results show that potentially high rates of sediment detachment can be induced not only by throughfall precipitation but also by larger throughfall drop size distributions at the concentrated impact location, even in the leafless season. Further studies with more replication building on this first report are necessary to investigate how many of these concentrated impact locations may occur on average with different tree species to better assess the extent of the erosion risk under forests.

Uncovering widespread Anthropocene dietary shifts in Chinese large mammalian herbivores.

The Anthropocene's human-dominated habitat expansion endangers global biodiversity. However, large mammalian herbivores experienced few extinctions during the 20th century, hinting at potentially overlooked ecological responses of a group sensitive to global change. Using dental microwear as a proxy, we studied large herbivore dietary niches over a century across mainland China before (1880s-1910s) and after (1970s-1990s) the human population explosion. We uncovered widespread and significant shifts (interspecific microwear differences increased and intraspecific microwear dispersion expanded) within dietary niches linked to geographical areas with rapid industrialization and population growth in eastern China. By contrast, in western China, where human population growth was slower, we found no indications of shifts in herbivore dietary niches. Further regression analysis links the intensity of microwear changes to human land-use expansion. These analyses highlight dietary adjustments of large herbivores as a likely key factor in their adaptation across a century of large-scale human-driven changes.

The Restructuring of Ecological Networks by the Pleistocene Extinction

Most terrestrial large mammals went extinct on different continents at the end of the Pleistocene, between 50,000 and 10,000 years ago. Besides the loss in species diversity and the truncation of body mass distributions, those extinctions were even more impactful to interaction diversity. Along with each extinction, dozens of ecological interactions were lost, reorganizing species interaction networks, which attained species-poor configurations with low functional redundancy. Extinctions of most large herbivores impacted energy flow and the rates of nutrient cycling, reconfiguring ecosystem-level networks. Because large mammals have high mobility, their loss also shortened seed-dispersal distance and reduced nutrient diffusivity, disrupting spatial networks. This review examines the recent advances in understanding how different types of ecological networks have been restructured by megafaunal extinctions and how this reorganization affected ecosystem functions. ▪Megafaunal extinctions resulted in the loss of multiple ecological interactions in terrestrial systems.▪Interaction loss reshaped different types of ecological networks including food webs and spatial networks.▪The reorganization of ecological networks changed how terrestrial ecosystems are structured and function.

Radiocarbon dates from the Netherlands and Doggerland as a proxy for vegetation and faunal biomass between 55 and 5 ka cal bp

ABSTRACTThree hundred forty‐one radiocarbon dates from the Groningen radiocarbon database are compiled in this study. They show for the first time that organic sediment samples from the eastern Netherlands and mammal bones from Doggerland reflect shifts in the presence and the density of vegetation (food for herbivores) and mammal biomass during the last ice age (Weichselian Stage, ~119–14.7 ka cal bp). Comparison with oxygen isotope curves of Greenland ice cores and geomorphological data shows that cold climate, in particular during the younger part of the Weichselian Middle Pleniglacial and during the Late Pleniglacial, and related scarcity or even absence of vegetation, were limiting factors for the carrying capacity of the landscape and thus for the population density of large herbivores during the period covered by 14C dating (last ca. 55 000 years). A ‘fossil gap’ during the Late Pleniglacial lasted ca. 13 000 years from ca. 28 to 15 ka cal bp. Previous research from the nearby Eifel region in Germany shows that environmental conditions were less extreme (‘refugium conditions’) than in the Netherlands, taking into account the continuous presence of spores of coprophilous fungi in the Eifel, indicating uninterrupted food supply for herbivores.

After the ‘Black Summer’ fires: Faunal responses to megafire depend on fire severity, proportional area burnt and vegetation type

Abstract Climate change and human activities have disrupted historical fire regimes, leading to complex and far‐reaching impacts on global ecosystems. Despite extensive research in fire ecology, studies exploring vertebrate responses to megafires, and to nuanced fire characteristics, remain limited. We collected camera trap data 3–27 months following Australia's 2019–20 ‘Black Summer’ megafires from 30 burnt sites and 10 unburnt sites. Our data included 14 animal species/groups, encompassing mammalian predators, small and medium‐sized mammals, large herbivores, and birds. We used generalised additive mixed models to assess the influence of time‐since‐the‐fires, burn status, fire severity, proportional area burnt, and vegetation type on species' activity. Models that included fire variables were well‐supported for all species. The proportional cover of low‐moderate or high‐extreme severity fire had substantial support for five species, particularly herbivores, which generally showed a preference for burnt sites but at differing fire severities. The proportional area burnt, disregarding severity, was well supported for four species. At highly burned sites fox activity peaked shortly after the fires while small to medium‐sized mammal activity increased more gradually. Vegetation type strongly influenced the response of four species to fire; in particular, wet forest birds preferred unburnt areas. Policy implications. We document variable short‐ to medium‐term responses of a range of species to fire which could help guide management interventions. We demonstrate that animal species' responses to fire are diverse and better captured using broader landscape scale fire variables. We found that species were strongly influenced by proportional area burnt, fire severity and vegetation type. Introduced foxes were attracted to recently burnt areas, so timely predator control may benefit vulnerable prey species. Wet forest species were sensitive to fires and could benefit from preservation and restoration of these habitats. Some species exploited low‐moderate severity burnt areas, while others preferred high‐severity burns. This suggests that species will face diverse challenges and opportunities in future extreme fire events. We emphasise the importance of using multi‐faceted approaches to account for the complex responses of co‐occurring species to fire events.

Predation risk drives long-term shifts in migratory behaviour and demography in a large herbivore population.

Migration is an adaptive life-history strategy across taxa that helps individuals maximise fitness by obtaining forage and avoiding predation risk. The mechanisms driving migratory changes are poorly understood, and links between migratory behaviour, space use, and demographic consequences are rare. Here, we use a nearly 20-year record of individual-based monitoring of a large herbivore, elk (Cervus canadensis) to test hypotheses for changing patterns of migration in and adjacent to a large protected area in Banff National Park (BNP), Canada. We test whether bottom-up (forage quality) or top-down (predation risk) factors explained trends in (i) the proportion of individuals using 5 different migratory tactics, (ii) differences in survival rates of migratory tactics during migration and whilst on summer ranges, (iii) cause-specific mortality by wolves and grizzly bears, and (iv) population abundance. We found dramatic shifts in migration consistent with behavioural plasticity in individual choice of annual migratory routes. Shifts were inconsistent with exposure to the bottom-up benefits of migration. Instead, exposure to landscape gradients in predation risk caused by exploitation outside the protected area drove migratory shifts. Carnivore exploitation outside the protected area led to higher survival rates for female elk remaining resident or migrating outside the protected area. Cause-specific mortality aligned with exposure to predation risk along migratory routes and summer ranges. Wolf predation risk was higher on migratory routes than summer ranges of montane-migrant tactics, but wolf predation risk traded-off with heightened risk from grizzly bears on summer ranges. A novel eastern migrant tactic emerged following a large forest fire that enhanced forage in an area with lower predation risk outside of the protected area. The changes in migratory behaviour translated to population abundance, where abundance of the montane-migratory tactics declined over time. The presence of diverse migratory life histories maintained a higher total population abundance than would have been the case with only one migratory tactic in the population. Our study demonstrates the complex ways in which migratory populations change over time through behavioural plasticity and associated demographic consequences because of individuals balancing predation risk and forage trade-offs.