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Emerging conservation efforts for the world's large predators may, if successful, restore natural predator–prey interactions. Marine reserves, where large predators tend to be relatively common, offer an experimental manipulation to investigate interactions between large-bodied marine predators and their prey. We hypothesized that southern stingrays—large, long-lived and highly interactive mesopredators—would invest in anti-predator behavior in marine reserves where predatory large sharks, the primary predator of stingrays, are more abundant. Specifically, we predicted southern stingrays in marine reserves would reduce the use of deep forereef habitats in the favor of shallow flats where the risk of shark encounters is lower. Baited remote underwater video was used to survey stingrays and reef sharks in flats and forereef habitats of two reserves and two fished sites in Belize. The interaction between "protection status" and "habitat" was the most important factor determining stingray presence. As predicted, southern stingrays spent more time interacting with baited remote underwater videos in the safer flats habitats, were more likely to have predator-inflicted damage inside reserves, and were less abundant in marine reserves but only in the forereef habitat. These results are consistent with a predation-sensitive habitat shift rather than southern stingray populations being reduced by direct predation from reef sharks. Our study provides evidence that roving predators can induce pronounced habitat shifts in prey that rely on crypsis and refuging, rather than active escape, in high-visibility, heterogeneous marine habitats. Given documented impacts of stingrays on benthic communities it is possible restoration of reef shark populations with reserves could induce reef ecosystem changes through behavior-mediated trophic cascades. [ABSTRACT FROM AUTHOR]

Both food abundance and predation risk may influence habitat use decisions. However, studies of habitat use by birds in marine environments have focused only on food abundance. I investigated the possible influences of food abundance and predation risk from tiger sharks ( Galeocerdo cuvier) on habitat use by pied cormorants ( Phalacrocorax varius) over two spatial scales and on cormorant group size. Cormorants were usually solitary, but group size was highest in shallow habitats during months when shark density was low. Regardless of season, cormorant density within shallow habitats was higher over seagrass than sand, and cormorants were distributed between these two microhabitats proportional to prey density. Therefore, cormorants appear to respond to prey abundance at a relatively narrow spatial scale (i.e., tens of meters). At the habitat-patch scale (~1 km), the density of cormorants and their prey (teleosts) was higher in shallow habitats than in deep ones, but the density of cormorants was influenced by an interaction between water temperature (i.e., season) and habitat. There was decreased use of shallow habitats as water temperature, and the density of tiger sharks, increased. When shark density was low, cormorants were distributed across habitats roughly in proportion to the abundance of fish, suggesting that cormorants respond to food abundance at the scale of habitat patches. However, as shark abundance increased, the relative density of cormorants dropped in the dangerous shallow habitats such that there was a greater density of cormorants relative to their food in deep habitats when sharks were abundant. This suggests that pied cormorants trade-off food and risk by accepting lower energetic returns to forage in safer habitats. This study provides the first evidence that marine habitat selection by birds may be influenced by such a trade-off, and provides further evidence that tiger sharks are important in determining habitat use of their prey and mediating indirect interactions within Shark Bay. [ABSTRACT FROM AUTHOR]

Predators can affect ecosystems through non‐consumptive effects (NCE) on their prey, which can lead to cascading effects on the vegetation. In mammalian communities, such cascading effects on whole ecosystems have mainly been demonstrated in protected areas, but the extent to which such effects may occur in more human‐dominated landscapes remains disputable. With the recolonisation of wolves Canis lupus in Europe, understanding the potential for such cascading processes becomes crucial for understanding the ecological consequences of wolf recovery and making appropriate management recommendations. Here, we investigate the evidence for non‐consumptive effects of wolves on their wild ungulate prey and cascading effects on the vegetation in European landscapes. We reviewed empirical studies reporting wild ungulate responses to wolves involving spatio‐temporal behaviour at large and fine spatial scales, activity patterns, vigilance, grouping, physiological effects, and effects on the vegetation. We reveal that non‐consumptive effects of wolves in Europe have been studied in few regions and with focus on regions with low human impact, are highly context‐dependent, and might often be overruled by human‐related factors. Hence, we highlight the need for a description of human influence in NCE studies. We discuss challenges in NCE research and the potential for advances in future research on NCE of wolves in a human‐dominated landscape. We emphasise the need for wildlife management to restore ecosystem complexity and processes, to allow non‐consumptive predator effects to occur. [ABSTRACT FROM AUTHOR]

This article discusses the observation of the critically endangered soupfin shark in the Changing Salish Sea. The study confirms the presence of soupfin sharks in Hammersley Inlet through fishing efforts and sampling. The findings suggest that the presence of soupfin sharks may have implications for trophic dynamics and fisheries management in the region. The article also provides a list of references for further research on marine ecosystems in the Salish Sea and surrounding areas. [Extracted from the article]

The 'landscape of fear' concept offers valuable insights into wildlife behaviour, yet its practical integration into habitat management for conservation remains underexplored. In this study, conducted in the subtropical monsoon grasslands of Bardia National Park, Nepal, we aimed to bridge this gap through a multi‐year, landscape‐scale experimental investigation in Bardia National Park, Nepal. The park has the highest density of tigers (with an estimated density of ~7 individuals per 100 km2) in Nepal, allowing us to understand the effect of habitat management on predation risk and resource availability especially for three cervid species: chital (Axis axis), swamp deer (Rucervus duvaucelii) and hog deer (Axis porcinus). We used plots with varying mowing frequency (0–4 times per year), size (ranging from small: 49 m2 to large: 3600 m2) and artificial fertilisation type (none, phosphorus, nitrogen) to assess the trade‐offs between probable predation risk and resources for these cervid species, which constitute primary prey for tigers in Nepal. Our results showed distinct responses of these deer to perceived predation risk within grassland habitats. Notably, these deer exhibited heightened use of larger plots, indicative of a perceived sense of safety, as evidenced by the higher occurrence of pellet groups in the larger plots (mean = 0.1 pellet groups m−2 in 3600 m2 plots vs. 0.07 in 400 m2 and 0.05 in 49 m2 plots). Furthermore, the level of use by the deer was significantly higher in larger plots that received mowing and fertilisation treatments compared to smaller plots subjected to similar treatments. Of particular interest is the observation that chital and swamp deer exhibited greater utilisation of the centre (core) areas within the larger plots (mean = 0.21 pellet groups m−2 at the centre vs. 0.13 at the edge) despite the edge (periphery) also provided attractive resources to these deer. In contrast, hog deer did not display any discernible reaction to the experimental treatments, suggesting potential species‐specific variations in response to perceived predation risk arising from management interventions. Our findings emphasise the importance of a sense of security as a primary determinant of habitat selection for medium‐sized deer within managed grassland environments. These insights carry practical implications for park managers, providing a nuanced understanding of integrating the 'landscape of fear' into habitat management strategies. This study emphasises that the 'landscape of fear' concept can and should be integrated into habitat management to maintain delicate predator–prey dynamics within ecosystems. [ABSTRACT FROM AUTHOR]

Understanding interactions within and between species is crucial to ecological research. However, for cetaceans such interactions can be difficult to observe in the field. Photographs offer an opportunity to study intra‐ and inter‐specific interactions, by capturing 'snapshots' of their occurrence over space and time. At‐surface and underwater photographs of bottlenose dolphins (Tursiops aduncus) inhabiting Ponta do Ouro Partial Marine Reserve (PPMR), Mozambique, were used to examine evidence of interactions with other dolphins, predators and ectoparasites. Intra‐specific scarring levels significantly differed by sex and age class, with males displaying more scarring than females. Similarly, adults had more scarring than juveniles or calves. Shark bites significantly differed in their distribution across dolphin body areas, with the dorsal side being more frequently wounded than the ventral side. The presence of barnacles was exclusive to fluke, dorsal and pectoral fins, and showed strong seasonal trends. Overall, this study demonstrates the value of photographs for examining marine ecological interactions. It provides the first insights regarding dolphin social behaviour, predation risk and health for this population. These in turn will support future research into the population dynamics and conservation of the PPMR dolphins, which is urgently required in the face of locally increasing anthropogenic pressures. [ABSTRACT FROM AUTHOR]

Extreme climatic events (ECEs) and predator removal represent some of the most widespread stressors to ecosystems. Though species interactions can alter ecological effects of climate change (and vice versa), it is less understood whether, when and how predator removal can interact with ECEs to exacerbate their effects. Understanding the circumstances under which such interactions might occur is critical because predator loss is widespread and ECEs can generate rapid phase shifts in ecosystems which can ultimately lead to tropicalization.Our goal was to determine whether loss of predation risk may be an important mechanism governing ecosystem responses to extreme events, and whether the effects of such events, such as tropicalization, can occur even when species range shifts do not. Specifically, our goal was to experimentally simulate the loss of an apex predator, the tiger shark Galeocerdo cuvier effects on a recently damaged seagrass ecosystem of Shark Bay, Australia by applying documented changes to risk‐sensitive grazing of dugong Dugong dugon herbivores.Using a 16‐month‐field experiment established in recently disturbed seagrass meadows, we used previous estimates of risk‐sensitive dugong foraging behaviour to simulate altered risk‐sensitive foraging densities and strategies of dugongs consistent with apex predator loss, and tracked seagrass responses to the simulated grazing.Grazing treatments targeted and removed tropical seagrasses, which declined. However, like in other mixed‐bed habitats where dugongs forage, treatments also incidentally accelerated temperate seagrass losses, revealing that herbivore behavioural changes in response to predator loss can exacerbate ECE and promote tropicalization, even without range expansions or introductions of novel species.Our results suggest that changes to herbivore behaviours triggered by loss of predation risk can undermine ecological resilience to ECEs, particularly where long‐lived herbivores are abundant. By implication, ongoing losses of apex predators may combine with increasingly frequent ECEs to amplify climate change impacts across diverse ecosystems and large spatial scales. [ABSTRACT FROM AUTHOR]

Information on how the trophic ecology of predators shapes their movement patterns and space-use is fundamental to understanding ecological processes across organisational levels. Despite this, studies combining spatial and trophic ecology to determine how prey preference and/or resource availability shape space use are lacking in marine predators as these can occur at low density and are often difficult to track over extended periods. Furthermore, many exhibit behavioural variability within species and among closely related, sympatric species adding further complexity. We applied a context-focused, multimethod approach to the understudied great hammerhead shark (Sphyrna mokarran) to test if movement and home ranges relate to prey preference and availability. Movement data from satellite and acoustic telemetry in Queensland, Australia, were combined with stable-isotope analysis, drone surveys, and videos of hunting behaviour. Limited dispersal, and small home ranges in S. mokarran were linked to trophic specialisation on stingray prey. Drone surveys and videos showed predation events on stingrays and demonstrated high, year-round availability of this prey in shallow, inshore habitats, which may allow the majority of S. mokarran to remain resident. This affinity for inshore habitats suggests that critical life-history requirements are performed over local or regional scales, although some larger movements were evident. These results were interpreted in comparison to the well-studied bull shark (Carcharhinus leucas), which showed reliance on pelagic food webs. Carcharhinus leucas had high individual variability in movement, with both large-scale migrations and residency. This could indicate that only some individuals are locally sustained on dynamic, pelagic food webs, while others undergo large-scale excursions over distant habitats. The specialised foraging of S. mokarran indicates they play an apex predator role in shallow, inshore habitats, potentially shaping space-use, and foraging behaviour of batoids. As inshore habitats are disproportionately affected by anthropogenic stressors, S. mokarran's trophic specialisation and limited demographic connectivity may make the species particularly vulnerable to anthropogenic threats. [ABSTRACT FROM AUTHOR]

Ungulates commonly select habitat with higher forage biomass and or nutritional quality to improve body condition and fitness. However, predation risk can alter ungulate habitat selection and foraging behavior and may affect their nutritional condition. Ungulates often choose areas with lower predation risk, sometimes sacrificing higher quality forage. This forage-predation risk trade-off can be important for life history strategies and influences individual nutritional condition and population vital rates. We used GPS collar data from adult female mule deer (Odocoileus hemionus) and mountain lions (Puma concolor) to model mule deer habitat selection in relation to forage conditions, stalking cover and predation risk from mountain lions to determine if a forage-predation risk trade-off existed for mule deer in central New Mexico. We also examined mountain lion kill sites and mule deer foraging locations to assess trade-offs at a finer scale. Forage biomass and protein content were inversely correlated with horizontal visibility, hence associated with higher stalking cover for mountain lions, suggesting a forage-predation risk trade-off for mule deer. Mule deer habitat selection was influenced by forage biomass and protein content at the landscape and within home range spatial scales, with forage protein being related to habitat selection during spring and summer and forage biomass during winter. However, mule deer selection for areas with better foraging conditions was constrained by landscape-scale encounter risk for mountain lions, such that increasing encounter risk was associated with diminished selection for areas with better foraging conditions. Mule deer also selected for areas with higher visibility when mountain lion predation risk was higher. Mountain lion kill sites were best explained by decreasing horizontal visibility and available forage protein, suggesting that deer may be selecting for forage quality at the cost of predation risk. A site was 1.5 timesmore likely to be a kill site with each 1-meter decrease in visibility (i.e., increased stalking cover). Mule deer selection of foraging sites was related to increased forage biomass, further supporting the potential for a trade-off scenario. Mule deer utilized spatio-temporal strategies and risk-conditional behavior to reduce predation risk, and at times selected suboptimal foraging areas with lower predation risk. [ABSTRACT FROM AUTHOR]

Army ants are widely recognized as keystone species in neotropical rainforests due to their role as important arthropod predators. Their large‐scale raids involve thousands of workers scouring the forest floor in pursuit of prey, primarily capturing other invertebrates. Up to 20 species of army ants coexist in a rainforest, and dietary niche differentiation has been proposed as a mechanism to alleviate competition among them. Based on only a handful of study sites, however, our understanding of the precise dietary preferences and the extent of niche differentiation remains notably limited. In this study, we aimed to expand our knowledge of army ant communities by resolving an Ecuadorian predation network consisting of 244 prey species and 13 army ant species representing the five known neotropical army ant genera: Cheliomyrmex, Eciton, Labidus, Neivamyrmex, and Nomamyrmex. We collected 2156 prey items from 180 army ant raids/emigrations, and of these, we identified 1945 prey items to the family level, 1313 to the genus level, and 664 to the species level based on morphological identifications and DNA barcodes. Prey consisted primarily of other ants (1843 prey items; 153 ant species), to the largest part ant brood (N = 1726). Hence, most army ant species chiefly plundered the nests of other ants, while the three swarm raiding species, that is, Lab. praedator, Lab. spininodis, and Ec. burchellii, exhibited a relatively high proportion of non‐ant invertebrate prey in their diet. The predation network showed a high degree of specialization (H2′ = 0.65), characterized by little dietary niche overlap among sympatric species. We compared the Ecuadorian network with one previously studied in Costa Rica and found that, despite the large geographic distance, prey preferences remained remarkably similar. We discovered species‐specific preferences for captured ant genera and species, despite some species turnover in both army ants and prey. Additionally, army ants also exhibited consistent spatiotemporal raiding preferences across study sites. In conclusion, predation preferences within army ant communities exhibited consistency in multiple niche dimensions across two distant neotropical rainforests, suggesting a notable level of predictability within army ant predation networks. [ABSTRACT FROM AUTHOR]

Mounting evidence indicates the non‐consumptive effects of predators significantly impact prey physiology, ecology and behaviour. Passerine birds experience adverse effects on nesting and reproductive success when in proximity to predators. Fear of predators is context‐dependent and influenced by hunting habitats and foraging strategies. While some bat species prey on birds, the greater noctule (Nyctalus lasiopterus) stands out by specialising in avian prey, especially during peak bird migration. N. lasiopterus is thought to seize avian prey in flight, but direct evidence is lacking. If birds were taken from nests, they would likely avoid nesting near these bats. However, no observations support this view. This study documents the successful reproduction of Eurasian blue tits (Cyanistes caeruleus) nesting alongside a colony of approximately 25 greater noctules. This bird species is a prey species for greater noctules in Italy. Over about 1 month (April–May 2023), we observed parent birds provisioning food to chicks, with at least two chicks alive and fed outside the tree cavity by the end of the period. While acknowledging the limitations of a single observation, we propose that this previously unknown behaviour indirectly supports the idea that greater noctules only capture avian prey in flight, not within confined spaces. This observation challenges the perception that these bats pose a threat when sharing roosting spaces in trees, as evidenced in our observed case. We hope this novel observation inspires future research on variations in bird nesting behaviour and reproductive success in the presence of bird‐eating bats, as well as an assessment of the long‐term impact on population dynamics and reproductive success of nesting birds sharing such roosting spaces. [ABSTRACT FROM AUTHOR]

Worldwide predation by feral cats has caused severe declines in many animal species. Prior to extinction, threatening processes typically alter species behaviour, habitat use, survival and reproductive rates. By monitoring these parameters, we may be able to determine if feral cats are a significant threatening process to a species prior to extinction. We aimed to test whether feral cats are negatively affecting the population size, morphometrics and movement patterns of mulgaras (Dasycercus blythi) on the Matuwa Indigenous Protected Area, in the arid rangelands of Western Australia. We hypothesised that mulgaras, which inhabit a cat-free environment, would have a larger home range and denser population, and be in better condition than those that inhabited an adjacent area with a suppressed density of feral cats. We trapped (n = 64), and radio-tracked (n = 19) mulgara inside and outside an I 100 ha cat-free fenced enclosure on five occasions in 2012. Treatment (i.e. inside or outside the cat-free enclosure) was a significant variable for explaining variation in mulgara density. There was no significant difference in morphometrics or the home ranges of mulgara between the sexes or treatments. Head length, pes length and weight, as well as tail width and length, were significantly different between sexes and over time, suggesting that seasonal variation influences mulgara populations more than low levels of cat predation. [ABSTRACT FROM AUTHOR]

Species assemblages are influenced by trophic and intraguild interactions, which may be competitive, facilitative, or neutral. These interactions vary in relative importance depending on resource availability. We assessed the nature of interactions among six carnivore species (Ursus arctos, Panthera uncia, Vulpes vulpes, Mustela altaica, and Martes foina) and their prey (Capra sibirica, Pseudois nayaur, Hemitragus jemlahicus, Moschus leucogaster, Ochotona sp., and Rodentia sp.) by examining their spatial–temporal overlaps using camera‐trap data gathered between 2016 and 2019 from the resource‐limited landscapes of the high Himalayas. We examined fine scale pairwise spatial interaction using multi‐species occupancy method and temporal overlap using time activity kernel densities function. Carnivore species showed relatively high spatio‐temporal overlap. We found spatial avoidance between two pairs and temporal avoidance between four out of 15 pairs. Contrary to our expectation that carnivore species would segregate due to competition in a resource‐poor environment, our results showed that they generally showed significant co‐occurrence and appeared to track their prey's activity. Our findings highlight the potentially overriding role of prey availability in influencing carnivore species occurrence in resource‐poor landscapes. [ABSTRACT FROM AUTHOR]

Reef shark species have undergone sharp declines in recent decades, as they inhabit coastal areas, making them an easy target in fisheries (i.e., sharks are exploited globally for their fins, meat, and liver oil) and exposing them to other threats (e.g., being part of by‐catch, pollution, and climate change). Reef sharks play a critical role in coral reef ecosystems, where they control populations of smaller predators and herbivorous fishes either directly via predation or indirectly via behavior, thus protecting biodiversity and preventing potential overgrazing of corals. The urgent need to conserve reef shark populations necessitates a multifaceted approach to policy at local, federal, and global levels. However, monitoring programmes to evaluate the efficiency of such policies are lacking due to the difficulty in repeatedly sampling free‐ranging, wild shark populations. Over nine consecutive years, we monitored juveniles of the blacktip reef shark (Carcharhinus melanopterus) population around Moorea, French Polynesia, and within the largest shark sanctuary globally, to date. We investigated the roles of spatial (i.e., sampling sites) and temporal variables (i.e., sampling year, season, and month), water temperature, and interspecific competition on shark density across 10 coastal nursery areas. Juvenile C. melanopterus density was found to be stable over 9 years, which may highlight the effectiveness of local and likely federal policies. Two of the 10 nursery areas exhibited higher juvenile shark densities over time, which may have been related to changes in female reproductive behavior or changes in habitat type and resources. Water temperatures did not affect juvenile shark density over time as extreme temperatures proven lethal (i.e., 33°C) in juvenile C. melanopterus might have been tempered by daily variation. The proven efficiency of time‐series datasets for reef sharks to identify critical habitats (having the highest juvenile shark densities over time) should be extended to other populations to significantly contribute to the conservation of reef shark species. [ABSTRACT FROM AUTHOR]

The relationship between aquatic and avian predators and prey is a fundamental process that influences the ecological dynamics of freshwater communities; a landscape of fear underpins spatial and temporal habitat use of prey, i.e., non‐consumptive predation effects. For example, complex marginal vegetation and other natural in‐river refuges are known to be important for prey to manage predation risk and predators must alter their behaviour in response to habitat patches prey occupy. However, it is unclear how prey respond to predators, and vice versa, in heavily modified degraded lowland rivers with a high degree of river maintenance measures; a component critical for flood risk management globally. Such modifications could lead to prey seeking refuge at hazardous anthropogenic infrastructure, but a robust quantification of predator–prey interactions in this context is required to develop this understanding.Using multi‐beam sonar (Dual‐Frequency Identification Sonar), we non‐invasively and simultaneously quantified the temporal rate of predator–prey interactions, the attack behaviour of predators, and the refuge seeking behaviour of prey at a pumping station intake during winter in a heavily modified lowland river.Prey fish experienced temporally dynamic, density‐dependant, and species‐specific predation risks from two dissimilar predators (i.e., aquatic vs. avian); pike (Esox lucius) and cormorant (Phalacrocorax carbo). Generalised linear modelling revealed that prey refuge use was positively associated with predator attack rate. Non‐consumptive effects were evidenced by quantified changes to shoal structure (density, area), shoaling (group aggregation), and schooling (coordinated directional movement), including diurnal migrations to and from the pumping station intake for refuge.Our results show that in the absence of natural refuge habitats the natural landscape of fear shifted and speculate that prey fish were paradoxically dependant on hazardous anthropogenic infrastructure, i.e., a pumping station intake, for refuge from predators in a degraded lowland river.These findings strongly enhance our understanding of the impact of anthropogenic infrastructure on predator–prey interactions by demonstrating how flood risk management, including river maintenance measures, and associated anthropogenic infrastructure can impact the behavioural game played between aquatic and avian predators and their prey. [ABSTRACT FROM AUTHOR]

Information on how the trophic ecology of predators shapes their movement patterns and space-use is fundamental to understanding ecological processes across organisational levels. Despite this, studies combining spatial and trophic ecology to determine how prey preference and/or resource availability shape space use are lacking in marine predators as these can occur at low density and are often difficult to track over extended periods. Furthermore, many exhibit behavioural variability within species and among closely related, sympatric species adding further complexity. We applied a context-focused, multi-method approach to the understudied great hammerhead shark (Sphyrna mokarran) to test if movement and home ranges relate to prey preference and availability. Movement data from satellite and acoustic telemetry in Queensland, Australia, were combined with stable-isotope analysis, drone surveys, and videos of hunting behaviour. Limited dispersal, and small home ranges in S. mokarran were linked to trophic specialisation on stingray prey. Drone surveys and videos showed predation events on stingrays and demonstrated high, year-round availability of this prey in shallow, inshore habitats, which may allow the majority of S. mokarran to remain resident. This affinity for inshore habitats suggests that critical life-history requirements are performed over local or regional scales, although some larger movements were evident. These results were interpreted in comparison to the well-studied bull shark (Carcharhinus leucas), which showed reliance on pelagic food webs. Carcharhinus leucas had high individual variability in movement, with both large-scale migrations and residency. This could indicate that only some individuals are locally sustained on dynamic, pelagic food webs, while others undergo large-scale excursions over distant habitats. The specialised foraging of S. mokarran indicates they play an apex predator role in shallow, inshore habitats, potentially shaping space-use, and foraging behaviour of batoids. As inshore habitats are disproportionately affected by anthropogenic stressors, S. mokarran’s trophic specialisation and limited demographic connectivity may make the species particularly vulnerable to anthropogenic threats. [ABSTRACT FROM AUTHOR]

Recolonization of predators to their former ranges is becoming increasingly prevalent. Such recolonization places predators among their prey once again; the latter having lived without predation (from such predators) for a considerable time. This renewed coexistence creates opportunities to explore predation ecology at both fundamental and applied levels. We used a paired experimental design to investigate white‐tailed deer risk allocation in the Upper and Lower Peninsulas (UP and LP) in Michigan, USA. Wolves are functionally absent in the LP, while deer in the UP coexist with a re‐established wolf population. We treated 15 sites each in UP and LP with wolf olfactory cues and observed deer vigilance, activity, and visitation rates at the interface of habitat covariates using remote cameras. Such a paired design across wolf versus no‐wolf areas allowed us to examine indirect predation effects while accounting for confounding parameters such as the presence of other predators and human activity. While wolf urine had no effect across most metrics in both UP and LP, we observed differences in deer activity in areas with versus without wolves. Sites treated with wolf urine in the UP showed a reduction in crepuscular deer activity, compared to control/novel‐scent treated sites. Furthermore, we observed a strong positive effect of vegetation cover on deer vigilance in these sites. This indicates that simulated predator cues likely affect deer vigilance more acutely in denser habitats, which presumably facilitates predation success. Such responses were however absent among deer in the LP that are presumably naïve toward wolf predation. Where human and non‐human predators hunt shared prey, such as in Michigan, predators may constrain human hunting success by increasing deer vigilance. Hunters may avoid such exploitative competition by choosing hunting/bait sites located in open areas. Our results pertaining to fundamental predation ecology have strong applied implications that can promote human–predator coexistence. [ABSTRACT FROM AUTHOR]

Group‐hunting is ubiquitous across animal taxa and has received considerable attention in the context of its functions. By contrast much less is known about the mechanisms by which grouping predators hunt their prey. This is primarily due to a lack of experimental manipulation alongside logistical difficulties quantifying the behaviour of multiple predators at high spatiotemporal resolution as they search, select, and capture wild prey. However, the use of new remote‐sensing technologies and a broadening of the focal taxa beyond apex predators provides researchers with a great opportunity to discern accurately how multiple predators hunt together and not just whether doing so provides hunters with a per capita benefit. We incorporate many ideas from collective behaviour and locomotion throughout this review to make testable predictions for future researchers and pay particular attention to the role that computer simulation can play in a feedback loop with empirical data collection. Our review of the literature showed that the breadth of predator:prey size ratios among the taxa that can be considered to hunt as a group is very large (<100 to >102). We therefore synthesised the literature with respect to these predator:prey ratios and found that they promoted different hunting mechanisms. Additionally, these different hunting mechanisms are also related to particular stages of the hunt (search, selection, capture) and thus we structure our review in accordance with these two factors (stage of the hunt and predator:prey size ratio). We identify several novel group‐hunting mechanisms which are largely untested, particularly under field conditions, and we also highlight a range of potential study organisms that are amenable to experimental testing of these mechanisms in connection with tracking technology. We believe that a combination of new hypotheses, study systems and methodological approaches should help push the field of group‐hunting in new directions. [ABSTRACT FROM AUTHOR]

Predators are widely recognized for their irreplaceable roles in influencing the abundance and traits of lower trophic levels. Predators also have irreplaceable roles in shaping community interactions and ecological processes via highly localized pathways (i.e. effects with well‐defined and measurable spatio–temporal boundaries), irrespective of their influence on prey density or behavior. We synthesized empirical and theoretical research describing how predators – particularly medium‐ and large‐sized carnivores – have indirect ecological effects confined to discrete landscape patches, processes we have termed 'patchy indirect effects (PIEs) of predation'. Predators generate PIEs via three main localized pathways: generating and distributing prey carcasses, creating ecological hotspots by concentrating nutrients derived from prey, and killing ecosystem engineers that create patches. In each pathway, the indirect effects are limited to discrete areas with measurable spatial and temporal boundaries (i.e. patches). Our synthesis reveals the diverse and complex ways that predators indirectly affect other species via patches, ranging from mediating scavenger interactions to influencing parasite/disease transmission risk, and from altering ecosystem biogeochemistry to facilitating local biodiversity. We provide basic guidelines on how these effects can be quantified at the patch and landscape scales, and discuss how predator‐mediated patches ultimately contribute to landscape heterogeneity and ecosystem functioning. Whereas density‐ and trait‐mediated indirect effects of predation generally occur through population‐scale changes, PIEs of predation occur through individual‐ and patch‐level pathways. Our synthesis provides a more holistic view of the functional role of predation in ecosystems by addressing how predators create patchy landscapes via localized pathways, in addition to influencing the abundance and behavior of lower trophic levels. [ABSTRACT FROM AUTHOR]

Predators can induce behavioral changes in prey that influence vigilance, grouping patterns, and space use, and these can ultimately affect prey demography and trophic interactions. Consequently, prey must respond to the risk of predation, but little is known about the features that drive the spatial responses of prey species to predators. We tested what factors affected the proximity of prey to the lions reintroduced to Addo Elephant National Park, South Africa. We also tested whether prey species that are preferentially killed by lions revealed greater responsiveness than those that are not, and whether prey respond to predator behavioral states and hunger. From 1588 observations of potential prey locations in relation to lions under varying wind directions, lion behaviors, and hunger states throughout the day and night, we found no evidence of wind‐driven odor responses affecting prey proximity to lions. Prey species that were not preferentially preyed upon by lions occurred closer to lions than those species that lions prefer to hunt. Prey were closer to lions performing noisy behaviors compared to those performing quiet behaviors. Prey were more likely to be closer to covertly behaving lions and further from stationary lions. Our results, compared to the published literature and accepted dogma of the primacy of odor in predator detection, suggest large vertebrate prey responses to predators in intact, multi‐species assemblages are context dependent. [ABSTRACT FROM AUTHOR]

Predation risk and prey responses exhibit fluctuations in space and time. Seasonal ecological disturbances can alter landscape structure and permeability to influence predator activity and efficacy, creating predictable patterns of risk for prey (seasonal risk landscapes). This may create corresponding seasonal shifts in antipredator behaviour, mediated by species ecology and trade‐offs between risk and resources. Yet, how human recreation interacts with seasonal risk landscapes and antipredator behaviour remains understudied.In South Florida, we investigated the impact of a seasonal ecological disturbance, specifically flooding, which is inversely related to human activity, on interactions between Florida panthers (Puma concolor coryi) and white‐tailed deer (Odocoileus virginianus). We hypothesized that human activity and ecological disturbances would interact with panther‐deer ecology, resulting in the emergence of two distinct seasonal landscapes of predation risk and the corresponding antipredator responses.We conducted camera trap surveys across southwestern Florida to collect detection data on humans, panthers and deer. We analysed the influence of human site use and flooding on deer and panther detection probability, co‐occurrence and diel activity during the flooded and dry seasons.Flooding led to decreased panther detections and increased deer detections, resulting in reduced deer‐panther co‐occurrence during the flooded season. Panthers exhibited increased nocturnality and reduced diel activity overlap with deer in areas with higher human activity. Supporting our hypothesis, panthers' avoidance of human recreation and flooding created distinct risk schedules for deer, driving their antipredator behaviour. Deer utilized flooded areas to spatially offset predation risk during the flooded season while increasing diurnal activity in response to human recreation during the dry season.We highlight the importance of understanding how competing risks and ecological disturbances influence predator and prey behaviour, leading to the generation of seasonal risk landscapes and antipredator responses. We emphasize the role of cyclical ecological disturbances in shaping dynamic predator–prey interactions. Furthermore, we highlight how human recreation may function as a 'temporal human shield,' altering seasonal risk landscapes and antipredator responses to reduce encounter rates between predators and prey. [ABSTRACT FROM AUTHOR]

Climate change has a profound impact on species distribution and abundance globally, as well as local diversity, which affects ecosystem functioning. In particular, changes in population distribution and abundance may lead to changes in trophic interactions. Although species can often shift their spatial distribution when suitable habitats are available, it has been suggested that predator presence can be a constraint on climate‐related distribution shifts. We test this using two well‐studied and data‐rich marine environments. Focusing on a pair of sympatric fishes, Atlantic haddock Melanogrammus aeglefinus and cod Gadus morhua, we study the effect of the presence and abundance of the latter on the former distribution. We found that the distribution of cod and increased abundance may limit the expansion of haddock to new areas and could consequently buffer ecosystem changes due to climate change. Though marine species may track the rate and direction of climate shifts, our results demonstrate that the presence of predators may limit their expansion to thermally suitable habitats. By integrating climatic and ecological data at scales that can resolve predator–prey relationships, this analysis demonstrates the usefulness of considering trophic interactions to gain a more comprehensive understanding and to mitigate the effects of climate change on species distributions. [ABSTRACT FROM AUTHOR]

Aim: Understanding the distribution of marine organisms is essential for effective management of highly mobile marine predators that face a variety of anthropogenic threats. Recent work has largely focused on modelling the distribution and abundance of marine mammals in relation to a suite of environmental variables. However, biotic interactions can largely drive distributions of these predators. We aim to identify how biotic and abiotic variables influence the distribution and abundance of a particular marine predator, the bottlenose dolphin (Tursiops truncatus), using multiple modelling approaches and conducting an extensive literature review. Location: Western North Atlantic continental shelf. Methods: We combined widespread marine mammal and fish and invertebrate surveys in an ensemble modelling approach to assess the relative importance and capacity of the environment and other marine species to predict the distribution of both coastal and offshore bottlenose dolphin ecotypes. We corroborate the modelled results with a systematic literature review on the prey of dolphins throughout the region to help explain patterns driven by prey availability, as well as reveal new ones that may not necessarily be a predator–prey relationship. Results: We find that coastal bottlenose dolphin distributions are associated with one family of fishes, the Sciaenidae, or drum family, and predictions slightly improve when using only fish versus only environmental variables. The literature review suggests that this tight coupling is likely a predator–prey relationship. Comparatively, offshore dolphin distributions are more strongly related to environmental variables, and predictions are better for environmental‐only models. As revealed by the literature review, this may be due to a mismatch between the animals caught in the fish and invertebrate surveys and the predominant prey of offshore dolphins, notably squid. Main Conclusions: Incorporating prey species into distribution models, especially for coastal bottlenose dolphins, can help inform ecological relationships and predict marine predator distributions. [ABSTRACT FROM AUTHOR]

While a large body of research has focused on the physiological effects of multiple environmental stressors, how behavioural and life‐history plasticity mediate multiple‐stressor effects remains underexplored. Behavioural plasticity can not only drive organism‐level responses to stressors directly but can also mediate physiological responses. Here, we provide a conceptual framework incorporating four fundamental trade‐offs that explicitly link animal behaviour to life‐history‐based pathways for energy allocation, shaping the impact of multiple stressors on fitness. We first address how small‐scale behavioural changes can either mediate or drive conflicts between the effects of multiple stressors and alternative physiological responses. We then discuss how animal behaviour gives rise to three additional understudied and interrelated trade‐offs: balancing the benefits and risks of obtaining the energy needed to cope with stressors, allocation of energy between life‐history traits and stressor responses, and larger‐scale escape from stressors in space or time via large‐scale movement or dormancy. Finally, we outline how these trade‐offs interactively affect fitness and qualitative ecological outcomes resulting from multiple stressors. Our framework suggests that explicitly considering animal behaviour should enrich our mechanistic understanding of stressor effects, help explain extensive context dependence observed in these effects, and highlight promising avenues for future empirical and theoretical research. [ABSTRACT FROM AUTHOR]

Copyright of Methods in Ecology & Evolution is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Predation risk causes prey to react in numerous ways, from life history changes to shifts in habitat. These responses give some insight into how different types of predators affect prey, but prey responses are often not comparable across taxa and experimental systems. Metabolism is a ubiquitous trait among living organisms, which offers a way to examine predator effects and create generalizable outcomes. We examined metabolic responses of terrestrial and aquatic prey from three antipredator functional groups under varied contexts of predator cues. We found that constitutively defended prey did not exhibit metabolic responses to any type of predator cues, while deimatic and freeze‐flight prey exhibited metabolic responses that were dependent on both the cue type and predator hunting mode. Consistent with previous studies on nonconsumptive effects, we also found that ambush predators elicited a metabolic response while active predators did not. We propose that future work on this topic should continue to take a metabolic approach as a unified, scalable response variable to the sensory ecology of nonconsumptive effects, while identifying additional systems that can evaluate more fully both predator hunting mode and prey antipredator defenses. [ABSTRACT FROM AUTHOR]

Human activities can influence behaviors of predators and prey, as well as predator–prey interactions. Using camera trap data, we investigated whether or to what extent human activities influenced behaviors of predators (tigers and leopards) and prey (sambar deer, spotted deer, wild boar, and barking deer), and predator–prey interactions in the Barandabhar Corridor Forest (BCF), Chitwan District, Nepal. A multispecies occupancy model revealed that the presence of humans altered the conditional occupancy of both prey and predator species. Specifically, the conditional occupancy probability of prey was substantially higher (ψ = 0.91, CI = 0.89–0.92) when humans were present than when humans were absent (ψ = 0.68, CI = 0.54–0.79). The diel activity pattern of most prey species overlapped strongly with humans, whereas predators were generally more active when humans were absent. Finally, the spatiotemporal overlap analysis revealed that human–prey interactions (i.e., the probability that both humans and prey species being present on the same grid at the same hourly period) was ~3 times higher (10.5%, CI = 10.4%–10.6%) compared to spatiotemporal overlap between humans and predators (3.1%, CI = 3.0%–3.2%). Our findings are consistent with the human shield hypothesis and suggest that ungulate prey species may reduce predation risk by using areas with high human activities. [ABSTRACT FROM AUTHOR]

Here, we assess whether fishery exploitation affects the trophic structure of carnivorous fish. We censused fish and analysed the stable isotope ratios of C and N of species targeted by fishermen in areas open to fishing and marine protected areas (MPAs) in the Mediterranean Sea and the north-eastern Atlantic Ocean. Results demonstrated a major impact of fishing on the biomass and size structure of nektobenthic carnivorous fish. However, those changes did not modify the diversity of the trophic resources used by the assemblage, the pattern of resource partitioning between species, or the degree of trophic redundancy. These results add to recent evidence suggesting that MPAs implemented in fished seascapes may fail to restore the original structure of the food webs that once existed in pre-fished ecosystems because regional decimation and extinction of highly mobile predators prevent recovering the original diversity of predators at local scales, even in no-take areas. If so, more strict local fishing regulations are unlikely to restore the original diversity of high trophic level carnivores and restoration goals should be reframed in terms of an objective that is less unrealistic than restoring the pre-fished condition while still recovering aspects of the historical trophic structure. [ABSTRACT FROM AUTHOR]

Predators and prey engage in games where each player must counter the moves of the other, and these games include multiple phases operating at different spatiotemporal scales. Recent work has highlighted potential issues related to scale‐sensitive inferences in predator–prey interactions, and there is growing appreciation that these may exhibit pronounced but predictable dynamics. Motivated by previous assertions about effects arising from foraging games between white‐tailed deer and canid predators (coyotes and wolves), we used a large and year‐round network of trail cameras to characterize deer and predator foraging games, with a particular focus on clarifying its temporal scale and seasonal variation. Linear features were strongly associated with predator detection rates, suggesting these play a central role in canid foraging tactics by expediting movement. Consistent with expectations for prey contending with highly mobile predators, deer responses were more sensitive to proximal risk metrics at finer spatiotemporal scales, suggesting that coarser but more commonly used scales of analysis may miss useful insights into prey risk‐response. Time allocation appears to be a key tactic for deer risk management and was more strongly moderated by factors associated with forage or evasion heterogeneity (forest cover, snow and plant phenology) than factors associated with the likelihood of predator encounter (linear features). Trade‐offs between food and safety appeared to vary as much seasonally as spatially, with snow and vegetation phenology giving rise to a "phenology of fear." Deer appear free to counter predators during milder times of year, but a combination of poor foraging state, reduced forage availability, greater movements costs, and reproductive state dampen responsiveness during winter. Pronounced intra‐annual variation in predator–prey interactions may be common in seasonal environments. [ABSTRACT FROM AUTHOR]

Predation risk effects are impacts on prey caused by predators that do not include consumption. These can include changes in prey behaviour, physiology, and morphology (i.e. risk‐induced trait responses), which can have consequences to individual fitness and population dynamics (i.e. non‐consumptive effects). While these risk‐induced trait responses (RITRs) can lower individual fitness as compared to prey not exposed to risk, they are assumed to increase fitness in the presence of predators. While much work has been built upon this assumption, most evidence occurs in consumptive experiments where the trait values of consumed prey are unknown. We have little evidence showing individuals with a greater magnitude of RITR have greater survival.Here, we tested the hypothesis that RITRs increase survival in the presence of predators, but come at a cost to growth. We tested this hypothesis using Nucella lapillus as prey and Carcinus maenas as a predator and including mussels as a basal resource in a two‐phase mesocosm experimental set‐up. In phase 1, Nucella were placed into either a control or risk treatment (exposure to non‐lethal Carcinus) for 28 days and their behaviour and growth measured. In phase 2, a lethal Carcinus was added to all mesocosms (non‐lethal crabs were removed), and survival was recorded for 15 days.At the treatment (group) level, we found that Nucella exposed to predation risk in phase 1 had significantly greater risk aversion behaviour (summed score of risky vs. safe behaviour) and significantly lower growth. In phase 2, we found that Nucella exposed to predation risk had greater survival.At the individual level (regardless of treatment), we found that Nucella with greater risk aversion scores in phase 1 had significantly higher survival in phase 2 when exposed to a lethal predator, but this came at a cost to their growth.This study provides some of the first empirical evidence, at both the group and individual level, testing a long‐held assumption that predation risk‐induced behavioural responses increase survival in the face of direct predation, but that these responses come at a cost to the prey. These results add to our growing understanding of the benefits of RITRs to individual fitness and non‐consumptive effects generally. [ABSTRACT FROM AUTHOR]

Wolves (Canis lupus) can exert top‐down pressure and shape ecological communities through the predation of ungulates and beavers (Castor spp.). Therefore, understanding wolf foraging is critical to estimating their ecosystem‐level effects. Specifically, if wolves are consumers that optimize tradeoffs between the cost and benefits of prey acquisition, changes in these factors may lead to prey‐switching or negative‐density dependent selection with potential consequences for community stability. For wolves, factors affecting cost and benefits include prey vulnerability, risk, reward, and availability, which can vary temporally. We described the wolf diet by the frequency of occurrence and percent biomass and characterized the diet using prey remains found in wolf scats on Isle Royale National Park, Michigan, USA, during May–October 2019 and 2020. We used logistic regression to estimate prey consumption over time. We predicted prey with temporal variation in cost (availability and/or vulnerability) such as adult moose (Alces alces), calf moose, and beaver (Castor canadensis) to vary in wolf diets. We analyzed 206 scats and identified 62% of remains as beaver, 26% as moose, and 12% as other species (birds, smaller mammals, and wolves). Adult moose were more likely to occur in wolf scats in May when moose are in poor condition following winter. The occurrence of moose calves peaked during June–mid‐July following birth but before calf vulnerability declined as they matured. By contrast, beaver occurrence in wolf scat did not change over time, reflecting the importance of low‐handling cost prey items for recently introduced lone or paired wolves. Our results demonstrate that the wolf diet is responsive to temporal changes in prey costs. Temporal fluctuation in diet may influence wolves' ecological role if prey respond to increased predation risk by altering foraging or breeding behavior. [ABSTRACT FROM AUTHOR]

Two major oceanographic changes have recently propagated through several trophic levels in coastal areas of Southeast Greenland (SEG). Firstly, the amount of drift‐ice exported from the Fram Strait and transported with the East Greenland Current (EGC) has decreased significantly over the past two decades, and a main tipping element (summer sea ice) has virtually disappeared since 2003 leading to a regime shift in oceanographic and ecological conditions in the region. The following 20‐year period with low or no coastal sea ice is unique in the 200‐year history of ice observations in the region, and the regime shift is also obvious in the volume of ice export through the Fram Strait after 2013. In the same period, the temperature of the EGC south of 73.5 N has increased significantly (>2°C) since 1980. Secondly, the warm Irminger Current, which advects warm, saline Atlantic Water into the region, has become warmer since 1990. The lack of pack ice in summer together with a warming ocean generated cascading effects on the ecosystem in SEG that are manifested in a changed fish fauna with an influx of boreal species in the south and the subarctic capelin further north. At higher trophic levels there has been an increase in the abundance of several boreal cetaceans (humpback, fin, killer, and pilot whales and dolphins) that are either new to this area or occur in historically large numbers. It is estimated that the new cetacean species in SEG are responsible for an annual predation level of 700,000 tons of fish. In addition, predation on krill species is estimated at >1,500,000 tons mainly consumed by fin whales. Simultaneously, there has been a reduction in the abundance and catches of narwhals and walruses in SEG and it is suggested that these species have been impacted by the habitat changes. [ABSTRACT FROM AUTHOR]

Information on resource use and trophic dynamics of marine predators is important for understanding their role in ecosystem functioning and predicting population‐level responses to environmental change. Where separate populations experience different local environmental conditions, geographic variability in their foraging ecology is often expected. Within populations, individuals also vary in morphology, physiology, and experience, resulting in specialization in resource use. In this context, isotopic compositions of incrementally grown tissues such as keratinous hairs offer a valuable opportunity to study long‐term variation in resource and habitat use. We investigated the trophic ecology of female Cape fur seals (Arctocephalus pusillus pusillus) using carbon and nitrogen isotopic compositions of serially sampled whiskers collected at four breeding sites along the coast of South Africa. Drawing on over 900 isotopic measurements, we assessed geographic variability in isotopic niche width between colonies and the degree of individual specialization. We found slight, but clear geographic differences in isotopic ratios and isotopic niche widths, seemingly related to ecological setting, with niche widths being proportional to the area of available shelf and shelf‐slope habitat surrounding the colony. We further identified periodic oscillations in isotopic ratios, which likely reflect temporal patterns in foraging distribution and prey type, linked to shifts in the availability of prey resources and their interaction with constraints on individual females throughout their breeding cycle. Finally, individual specialization indices revealed that each of the study populations contain specialist individuals that utilize only a small subset of the total population niche width. The degree of individual specialization was, however, not consistent across colonies and may reflect an interactive influence between density‐dependent effects and habitat heterogeneity. Overall, this study provides important information on the trophic ecology of Cape fur seals breeding in South Africa and highlights the need to consider geographic and individual variability when assessing the foraging ecology of marine predators. [ABSTRACT FROM AUTHOR]

Understanding how megaherbivores incorporate habitat features into their foraging behavior is key toward understanding how herbivores shape the surrounding landscape. While the role of habitat structure has been studied within the context of predator–prey dynamics and grazing behavior in terrestrial systems, there is a limited understanding of how structure influences megaherbivore grazing in marine ecosystems. To investigate the response of megaherbivores (green turtles) to habitat features, we experimentally introduced structure at two spatial scales in a shallow seagrass meadow in The Bahamas. Turtle density increased 50‐fold (to 311 turtles ha−1) in response to the structures, and turtles were mainly grazing and resting (low vigilance behavior). This resulted in a grazing patch exceeding the size of the experimental setup (242 m2), with reduced seagrass shoot density and aboveground biomass. After structure removal, turtle density decreased and vigilance increased (more browsing and shorter surfacing times), while seagrass within the patch partly recovered. Even at a small scale (9 m2), artificial structures altered turtle grazing behavior, resulting in grazing patches in 60% of the plots. Our results demonstrate that marine megaherbivores select habitat features as foraging sites, likely to be a predator refuge, resulting in heterogeneity in seagrass bed structure at the landscape scale. [ABSTRACT FROM AUTHOR]

The article discusses the spatial variation in shark-inflicted injuries to Indo-Pacific bottlenose dolphins of the southwestern Indian Ocean. Topics include predation risk critical in shaping the behavior and population dynamics of prey taxa, populations of small delphinids at risk from predators, and predation risk from Killer whales primarily in temperate waters.

Local populations of marine benthic macro‐invertebrates with planktonic larvae are believed to be in source–sink relationships via larval dispersal in a regional population complex. Practically, such a region is definable only after connectivity of constituent local populations is explored. Numerical simulations abound for hydrodynamic connectivity by larvae between local/regional populations. Empirical studies have scarcely integrated inter‐local connectivity and intra‐local population dynamics into demographic connectivity analysis. I review the current research and indicate fundamental and technical problems to demonstrate that some source–sink systems in intertidal shores, which are most accessible among benthic habitats, are a good model. The challenge in benthic source–sink research comes from that existent local populations may not be self‐sustaining because of low larval self‐seeding rates and/or low benthos' survival rates and yet can persist as latent sinks. They may receive larvae leaking from sources at good‐quality habitat patches with stationary larval retention areas for self‐recruitment. On an intertidal sandflat in an estuary–coastal ocean region, Kyushu, Japan during 1979–2019, the population of a trochid gastropod with 3‐ to 9‐day larval duration became extinct and recovered. The extinction was caused by sediment destabilization by a callianassid shrimp population which increased in the early 1980s. The gastropod recovery was owing to the shrimp decline by stingray predation and the transport of larvae from some self‐sustainable populations with lower shrimp densities 30 km away. It was estimated that the gastropod population before the shrimp proliferation on that sandflat might be a latent sink requiring allochthonous larval subsidy due to epi‐benthic predation on juveniles. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Animal Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although the nighttime ecology of organisms remains understudied, nocturnal surveys play an integral part in assessing fish assemblages and the selective forces shaping them. Eleuthera (Bahamas) contains an unusual population of lined seahorses (Hippocampus erectus) in an anchialine lake, possessing morphological characteristics distinct from those found in the ocean. Population surveys for seahorses and their potential predators were conducted at midnight and midday during wet and dry seasons, with belt transects perpendicular to the shoreline that increased in depth away from shore. Nocturnal surveys uncovered seahorse densities 259% higher than daytime transects on average. Sex ratios were consistently male‐biased, and the frequency of animals from different reproductive categories varied significantly by time of day, with gravid males observed around the clock but females and nongravid males observed more often at night. Spatial and seasonal recruitment was detected for the first time in this species, with an increase in juveniles detected in the shallow ends of transects during dry season surveys. Juvenile recruitment is poorly understood across syngnathid fishes, so the detection of early recruits at night has broad implications for this fish family. Seahorses from all reproductive categories were perched significantly higher in the water column during the night regardless of their depth or season. Predator densities followed a similar pattern with higher densities observed at night, indicating that elevated nocturnal perch height may be a response to predator presence. However, the selective agents driving these nocturnal behaviors have yet to be identified. Considering H. erectus is listed on the IUCN Red List as "Vulnerable," the increase in nocturnal population size and the detection of juveniles has crucial implications for understanding their ecology, recruitment, and conservation. [ABSTRACT FROM AUTHOR]

Evaluating the patterns and generality of ontogenetic dietary shifts (ODSs) contributes to understanding prey–predator interactions and food web dynamics. Numerous studies have focused on predators that target distinctively lower trophic‐level organisms. However, the ODS of predators that routinely prey on organisms at similar trophic levels (i.e., predator‐eating predators) have been neglected in ODS research. The ODS patterns of predator eaters may not fit into conventional frameworks owing to constraints of potential capture risk (e.g., deadly counterattack from prey) and body size. We aimed to reveal the ODS patterns of predator eaters and determine whether the patterns were affected by body size and capture risk. Assuming that capture risk is a significant factor in ODS patterns, we expected: (1) juvenile araneophagic spiders to forage on non‐dangerous prey (insects) and capture larger non‐dangerous prey more frequently than dangerous prey (spiders); and (2) as they grow, their prey types will shift from non‐dangerous to dangerous prey because larger predators will be able to capture dangerous prey as the optimal food. As a result of field observations, we revealed that the major ODS pattern in these spiders changed from a mixed (both insect and spider) to a spider‐dominant diet. The model selection approach showed that this diet shift was partly due to predator size, and the relative importance of predator size was higher than the life stage per se and almost equal to species identity. In these spiders, the body size of spider prey tended to be smaller than that of insects when the predators were small, suggesting that capture risk may be a critical factor in determining the ODS patterns of these predators. Therefore, our study adds to the evidence that the capture risk is crucial in comprehensively understanding the mechanisms determining ODS patterns in natural systems. [ABSTRACT FROM AUTHOR]

Perceived predation risk varies in space and time. Foraging in this landscape of fear alters forager‐resource interactions via cascading nonconsumptive effects. Estimating these indirect effects is difficult in natural systems. Here, we applied a novel measure to quantify the diversity at giving‐up density that allows to test how spatial variation in perceived predation risk modifies the diversity of multispecies resources at local and regional spatial levels. Furthermore, we evaluated whether the nonconsumptive effects on resource species diversity can be explained by the preferences of foragers for specific functional traits and by the forager species richness. We exposed rodents of a natural community to artificial food patches, each containing an initial multispecies resource community of eight species (10 items each) mixed in sand. We sampled 35 landscapes, each containing seven patches in a spatial array, to disentangle effects at local (patch) and landscape levels. We used vegetation height as a proxy for perceived predation risk. After a period of three nights, we counted how many and which resource species were left in each patch to measure giving‐up density and resource diversity at the local level (alpha diversity) and the regional level (gamma diversity and beta diversity). Furthermore, we used wildlife cameras to identify foragers and assess their species richness. With increasing vegetation height, i.e., decreasing perceived predation risk, giving‐up density, and local alpha and regional gamma diversity decreased, and patches became less similar within a landscape (beta diversity increased). Foragers consumed more of the bigger and most caloric resources. The higher the forager species richness, the lower the giving‐up density, and alpha and gamma diversity. Overall, spatial variation of perceived predation risk of foragers had measurable cascading effects on local and regional resource species biodiversity, independent of the forager species. Thus, nonconsumptive predation effects modify forager‐resource interactions and might act as an equalizing mechanism for species coexistence. [ABSTRACT FROM AUTHOR]

Social information use is well documented across the animal kingdom, but how it influences ecological and evolutionary processes is only just beginning to be investigated. Here we evaluate how social transmission may influence species interactions and potentially change or create novel selection pressures by focusing on predator–prey interactions, one of the best studied examples of species coevolution. There is extensive research into how prey can use social information to avoid predators, but little synthesis of how social transmission among predators can influence the outcome of different stages of predation. Here we review evidence that predators use social information during 1) encounter, 2) detection, 3) identification, 4) approach, 5) subjugation and 6) consumption. We use this predation sequence framework to evaluate the implications of social information use on current theoretical predictions about predator–prey dynamics, and find that social transmission has the potential to alter selection pressures for prey defences at each predation stage. This suggests that considering social interactions can help answer open questions about species coevolution, and also predict how populations and communities respond to rapid human‐induced changes in the environment. [ABSTRACT FROM AUTHOR]

Dispersal of organisms between patches is a common phenomenon in ecology and plays an important role in predator–prey population dynamics. We propose a nonsmooth Filippov predator–prey model in a two-patch environment characterized by a generalist predator-driven intermittent refuge protection of an apprehensive prey along with a balanced dispersal of the prey between refuge and nonrefuge areas. By employing qualitative techniques of nonsmooth dynamical systems, we see that the switching surface is a repeller whenever the interior equilibria are virtual, causing long-term population fluctuations. We find that the level of prey vigilance and the rate of prey dispersal play pivotal roles in the total harvesting yield. We observe that a sustainable high harvesting yield is possible when the prey is less vigilant and obtain the harvesting efforts for maximum sustainable total yield (MSTY). We further modify the model by considering a continuous threshold predator-driven prey dispersal and show that the model exhibits a Hopf bifurcation when the level of prey vigilance exceeds some critical threshold value. By comparing the dynamics of the two models we see that for a sustainable high harvesting yield of the system with continuous threshold dispersal, the prey needs to be highly vigilant compared to that of the system with intermittent dispersal of the prey. Further, we find numerically that the estimated MSTY from both models remains the same. [ABSTRACT FROM AUTHOR]

Trophic ecology studies on predator–prey interactions reveal insights into ecological communities and help understand a species' role in the food web by contributing to improved fisheries management and conservation capabilities. Understanding the ecological role of overexploited and endangered predators is essential to deciphering how their feeding behaviour influences food web dynamics. In this study, the authors investigated the feeding behaviour of the common and IUCN‐listed Near Threatened (NT) thornback ray Raja clavata, using carbon and nitrogen stable isotope and stomach content analysis (SCA). It has recently suffered an 87% decline in reported catches from the Sea of Marmara within the last decade. These results show that thornback ray mainly feeds on teleost species, except in summer, with both methods showing this species changes its diet ontogenetically by SCA. This ontogenetic diet shift was at lengths 40–50 cm by changing group preferences from Crustacea to Teleostei. MixSIAR results showed that both adult and juvenile individuals of R. clavata feed mainly on the crustaceans, but the contribution of teleosts represented by Trachurus sp. was very low (<15%). The trophic position increased total length and was higher than other batoid species in the Sea of Marmara. [ABSTRACT FROM AUTHOR]

Carnivore intraguild dynamics depend on a complex interplay of environmental affinities and interspecific interactions. Context‐dependency is commonly expected with varying suites of interacting species and environmental conditions but seldom empirically described. In South Africa, decentralized approaches to conservation and the resulting multi‐tenure conservation landscapes have markedly altered the environmental stage that shapes the structure of local carnivore assemblages. We explored assemblage‐wide patterns of carnivore spatial (residual occupancy probability) and temporal (diel activity overlap) co‐occurrence across three adjacent wildlife‐oriented management contexts—a provincial protected area, a private ecotourism reserve, and commercial game ranches. We found that carnivores were generally distributed independently across space, but existing spatial dependencies were context‐specific. Spatial overlap was most common in the protected area, where species occur at higher relative abundances, and in game ranches, where predator persecution presumably narrows the scope for spatial asymmetries. In the private reserve, spatial co‐occurrence patterns were more heterogeneous but did not follow a dominance hierarchy associated with higher apex predator densities. Pair‐specific variability suggests that subordinate carnivores may alternate between pre‐emptive behavioral strategies and fine‐scale co‐occurrence with dominant competitors. Consistency in species‐pairs diel activity asynchrony suggested that temporal overlap patterns in our study areas mostly depend on species' endogenous clock rather than the local context. Collectively, our research highlights the complexity and context‐dependency of guild‐level implications of current management and conservation paradigms; specifically, the unheeded potential for interventions to influence the local network of carnivore interactions with unknown population‐level and cascading effects. [ABSTRACT FROM AUTHOR]

Patchy resource distribution can cluster predator activity around areas of the highest productivity in ecosystems. For the endangered Western Spiny‐tailed Skink (Egernia stokesii badia) in Western Australia, the log piles that they permanently inhabit in an otherwise patchy, arid landscape, represent a potentially reliable, high abundance food source for predators. Not only are encounter rates by potential predators of E. s. badia likely to be influenced by vegetation structure at the microhabitat scale but also E. s. badia occurs in a region where mine sites and associated infrastructure, such as landfill sites, likely concentrate generalist predators (e.g. Feral Cats and corvids). We assessed the influence of the presence of coarse woody debris (CWD) and distance to the landfill on predator behaviour towards E. s. badia through plasticine model experiments, unbounded point count bird surveys and camera trapping. We found that CWD inhabited by E. s. badia attracted a greater relative activity of corvids compared with uninhabited CWD, or control sites without CWD. The relative activity of corvids and predatory birds combined increased with decreasing distance from the landfill. Preferential hunting by corvids at CWD inhabited by E. s. badia compared to both uninhabited CWD and open sites suggests that inhabited CWD may be targeted by generalist predators in the region, and that adaptive management may be required for species conservation around active mining areas. [ABSTRACT FROM AUTHOR]

For both prey species and mesocarnivores, fear of predators can result in behavioural strategies that reduce predation risk and interspecific competition. Two common strategies are spatial avoidance of high-risk areas and modifying activity patterns. This study investigated, by the use of camera traps, the role of wolf (Canis lupus) predation risk in shaping the temporal patterns of four species of ungulates and two species of mesocarnivores in a protected area of the Italian Western Alps. Additionally, we looked into potential differences in the anti-predator behaviour of two species (the roe deer (Capreolus capreolus) and the wild boar (Sus scrofa)) related to the age class or the sex of the individuals. The activity of the wild boar resulted quite similar to that of wolf, but young and subadults were recorded more in low-risk sites. As regarding the main prey of the wolf, namely the roe deer, its activity became more diurnal in high-risk areas, with different peaks between male and female. The red fox (Vulpes vulpes) turned out to be strongly associated with the wolf, in terms of daily cycle, suggesting a positive interaction probably due to the trophic facilitation phenomenon. These findings further our understanding of the diversity of interspecific relationships and community responses to the gray wolf, a species whose range in Europe has undergone recent expansion. [ABSTRACT FROM AUTHOR]

Interspecific interactions can play an essential role in shaping wildlife populations and communities. To date, assessments of interspecific interactions, and more specifically predator–prey dynamics, in aquatic systems over broad spatial and temporal scales (i.e., hundreds of kilometers and multiple years) are rare due to constraints on our abilities to measure effectively at those scales. We applied new methods to identify space‐use overlap and potential predation risk to Atlantic tarpon (Megalops atlanticus) and permit (Trachinotus falcatus) from two known predators, great hammerhead (Sphyrna mokarran) and bull (Carcharhinus leucas) sharks, over a 3‐year period using acoustic telemetry in the coastal region of the Florida Keys (USA). By examining spatiotemporal overlap, as well as the timing and order of arrival at specific locations compared to random chance, we show that potential predation risk from great hammerhead and bull sharks to Atlantic tarpon and permit are heterogeneous across the Florida Keys. Additionally, we find that predator encounter rates with these game fishes are elevated at specific locations and times, including a prespawning aggregation site in the case of Atlantic tarpon. Further, using machine learning algorithms, we identify environmental variability in overlap between predators and their potential prey, including location, habitat, time of year, lunar cycle, depth, and water temperature. These predator–prey landscapes provide insights into fundamental ecosystem function and biological conservation, especially in the context of emerging fishery‐related depredation issues in coastal marine ecosystems. [ABSTRACT FROM AUTHOR]

Coevolution with predators leads to the use of low‐risk habitats by many prey species, which promotes survival during early developmental phases. These nurseries are valued by conservation and management agencies because of their contributions to adult populations. However, the physical and geographic characteristics, like shallow depths and isolation from other marine habitats, that restrict access to predators and thereby reduce risk to juvenile animals can also limit scientific research. Consequently, many nursery habitats are still unidentified and understudied. Here we used gillnet monitoring from 1982 to 2018 to delineate blacktip shark (Carcharhinus limbatus) nurseries in the north‐western Gulf of Mexico and elucidated their physical, environmental and biological characteristics. Nursery habitats within estuaries (<2% of spatial area) were proximate to the Gulf of Mexico and exhibited significantly lower variability in salinity than non‐nurseries. However, relative abundances of predators and prey were not significant delineators of nursery habitats. As such, food and risk may not influence juvenile blacktip habitat use as expected. Alternatively, reduced osmoregulatory stress attributed to predictable environments likely provides advantageous conditions for blacktips to develop foraging and antipredator tactics, which is vital prior to the winter migration of juvenile sharks into the Gulf of Mexico. [ABSTRACT FROM AUTHOR]

Large carnivores play critical roles in terrestrial ecosystems but have suffered dramatic range contractions over the past two centuries. Developing an accurate understanding of large carnivore diets is an important first step towards an improved understanding of their ecological roles and addressing the conservation challenges faced by these species.The puma is one of seven large felid species in the world and the only one native to the non‐tropical regions of the New World. We conducted a meta‐analysis of puma diets across the species' range in the Americas and assessed the impact of varying environmental conditions, niche roles, and human activity on puma diets. Pumas displayed remarkable dietary flexibility, consuming at least 232 different prey species, including one Critically Endangered and five Endangered species.Our meta‐analysis found clear patterns in puma diets with changing habitat and environmental conditions. Pumas consumed more larger‐bodied prey species with increasing distance from the equator, but consumption of medium‐sized species showed the opposite trend.Puma diets varied with their realized niche; however, contrary to our expectations, puma consumption of large species did not change with their trophic position, and pumas consumed more small prey and birds as apex predators. Consumption of domestic species was negatively correlated with consumption of medium‐sized wild species, a finding which underscores the importance of maintaining intact native prey assemblages.The tremendous dietary flexibility displayed by pumas represents both an opportunity and a challenge for understanding the puma's role in ecosystems and for the species' management and conservation. Future studies should explore the linkages between availability and selection of primary and other wild prey, and consequent impacts on predation of domestic species, in order to guide conservation actions and reduce conflict between pumas and people. [ABSTRACT FROM AUTHOR]

Research longline sampling was conducted seasonally from December 2006 to February 2009 to investigate the occurrence and population structure of the broadnose sevengill shark Notorynchus cepedianus in coastal areas of south-east Tasmania. Notorynchus cepedianus showed a consistent temporal trend in seasonal occurrence in Norfolk Bay characterized by high abundances in summer to near absence in winter. This pattern was less pronounced in the Derwent Estuary, where fish were still caught during winter. The absence of smaller total length ( L) classes (<80 cm) from the catches suggests that N. cepedianus are not using these coastal habitats as nursery areas. Of the 457 individuals tagged, 68 (15%) were recaptured. Time at liberty ranged from 6 days to almost 4 years and all but one of the recaptures were caught in its original tagging location, suggesting site fidelity. The large number of N. cepedianus in these coastal systems over summer indicates that these areas are important habitats for this species and that N. cepedianus may have a significant influence on community dynamics through both direct and indirect predator-prey interactions. [ABSTRACT FROM AUTHOR]