Diel Activity Patterns Research Articles

Empirically testing the influence of light regime on diel activity patterns in a marine predator reveals complex interacting factors shaping behaviour

Abstract Diel cycles in marine predator diving behaviour centre around the light‐mediated diel vertical migration (DVM) of prey, and are considered critical for optimizing foraging and limiting competition across global seascapes. Yet, our understanding of predator diel behaviour is based primarily on examining relative depth usage between constant day/night cycles with no formal investigation of how varying light regimes interact with abiotic factors to shape diel activity. The extreme seasonal light regimes (midnight sun, polar night, day/night cycle) in the Arctic provide a unique natural experimental setting to empirically investigate the occurrence and intensity of diel behaviour in marine predators relative to changing light levels while concomitantly assessing interacting abiotic factors. Depth time series data from satellite‐linked tags deployed on six beluga whales (Delphinapterus leucas) for up to 12 months were used to quantify diel behaviour by calculating dissimilarity in time‐at‐depth between periods of low and high solar altitude on each day. Generalized additive mixed effects models were used to examine the influence of hours of daylight across extreme light cycles, coupled with bathymetry and sea ice concentration; focal diel patterns were further examined relative to the thermal structure of the water column. As predicted, belugas exhibited cathemerality during the midnight sun, and initiated diel behaviour with the onset of the fall day/night cycle, with a marked increase in its intensity with the progression to equal day/night length. Occurrence of diel patterns, however, was complex; ceasing in regions with seafloor depths <700 m, and occurring with greatest intensity when the water column was thermally homogeneous within the upper 150 m. Through empirical investigation, this study demonstrates that the onset of day/night light cycles and presumably associated prey DVM can modulate predator diel dive behaviour under certain circumstances, but highlights how the complex interaction of abiotic factors with light regime shape dynamic spatiotemporal patterns. These findings, building on a body of recent work, emphasize that the traditional view of the ubiquitous occurrence of diel behaviour tied to DVM at the base of the food web oversimplifies vertical predator–prey interactions, identifying the need for more structured investigation. Read the free Plain Language Summary for this article on the Journal blog.

Using skin temperature and activity profiles to assign chronotype in birds

Chronotypes describe consistent differences between individuals in biological time-keeping. They have been linked both with underlying variation in the circadian system and fitness. Quantification of chronotypes is usually by time of onset, midpoint, or offset of a rhythmic behaviour or physiological process. However, diel activity patterns respond flexibly to many short-term environmental influences, which can make chronotypes hard to identify. In contrast, rhythmic patterns in physiological processes, such as body temperature, may provide more robust insights into the circadian basis of chronotypes. These can be telemetrically recorded from skin-mounted, temperature-sensitive transmitters, offering minimally invasive opportunities for working on free-ranging animals in the wild. Currently, computational methods for deriving chronotype from skin temperature require further development, as time series are often noisy and incomplete. Here, we investigate such methods using simultaneous radio telemetry recordings of activity and skin temperature in a wild songbird model (Great Tit Parus major) temporarily kept in outdoor aviaries. Our aims were to first develop standardised selection criteria to filter noisy time series of skin temperature and activity, to second assign chronotype based on the filtered recordings, and to third compare chronotype as assigned based on each of the two rhythms. After the selection of rhythmic data using periodicity and autocorrelation parameters, chronotype estimates (onset and offset) were extracted using four different changepoint approaches for skin temperature and one approach for activity records. The estimates based on skin temperature varied between different approaches but were correlated to each other (onset: correlation coefficient r = 0.099–0.841, offset: r = 0.131–0.906). In contrast, chronotype estimates from skin temperature were more weakly correlated to those from activity (onset: r = −0.131–0.612, offset: r = −0.040– −0.681). Overall, chronotype estimates were less variable and timed later in the day for activity than for skin temperature. The distinctions between physiological and behavioural chronotypes in this study might reflect differences in underlying mechanisms and in responsiveness to external and internal cues. Thus, studying each of these rhythms has specific strengths, while parallel studies of both could inform broadly on natural variation in biological time-keeping, and may allow assessment of how biological rhythms relate to changes in the environment.

Patterns of spatial distribution, diel activity and human-bear conflict of Ursus thibetanus in the Hindu Kush mountains, Pakistan

The Asiatic black bear ( Ursus thibetanus ) is an elusive mammal and its conservation is currently a challenge in Pakistan due to the negative interaction with human communities and habitat fragmentation. We investigated the distribution, activity pattern and human-bear conflict of the Asiatic black bear in the Hindu Kush, a major mountains system in Pakistan. Our study was conducted from October 2020 to December 2020 in the Bahrain Valley, placed in the southeastern area of the Hindu Kush. We firstly carried out a preliminary sign survey for the bear's presence and, then, we installed an infrared sensor camera traps in the potential suitable habitat for the bear, 23 locations for 152 trap nights, to monitor its activity. Furthermore, to understand human-bear conflict, a questionnaire survey was submitted to 107 local people living in the bear’s habitat. The Asiatic black bear was photographed in 12 camera stations with 60 different capture events. We obtained a trap success percent of 64.8% between 2,100 m - 2,400 m above the sea level while the total trap success calculated for the whole camera trapping survey of the bears was 39.5%. The bears showed a bimodal activity pattern with peaks just after sunset and during the night (88% of observations from 00:00 to 06:00 and 18:00 to 24:00). We observed that the female and male bears and their puppies were not hibernating in subzero temperatures until December. Local communities had concerns over livestock and crops losses in the area. Our findings showed once again that the Asiatic black bear urgently needs effective management plans to guarantee its conservation in Pakistan.

Diel timing of migration is not plastic in a migratory ungulate

The temporal windows during which animals complete essential life processes (i.e. temporal niche) allow animals to match their actions to a given environmental context. When completing seasonal migrations, some migrants switch their activity patterns (e.g. from diurnal to nocturnal in multiple species of migratory birds) to take advantage of better conditions. We tested the temporal niche-switch hypothesis by comparing activity patterns before and during migration for four populations of migratory mule deer, Odocoileus hemionus , in western Wyoming, U.S.A. (2007–2019). We predicted that the physically taxing and risky event of terrestrial migration would prompt shifts in diel activity patterns. In contrast to the niche-switch hypothesis, mule deer did not drastically change their activity patterns during migration. Both before and during migration, mule deer were crepuscular (i.e. most active during twilight hours). When migrating in the spring, however, mule deer tended to concentrate activity near dawn, although they did not concentrate activity near dawn in the autumn, when less snow was present. By moving in the morning during spring migration, mule deer moved when snow was hardest, potentially allowing them to avoid the energetic costs of sinking into deep snow. Mule deer overall maintained a consistent pattern of crepuscular activity, but fine-tuned their activity patterns during migration, which may allow them to better match their behaviours with environmental conditions while completing an important life event. Rather than abandoning activity patterns, animals instead may make subtle alterations in their activity patterns to take advantage of present conditions. • Mule deer did not switch the time of day that they were most active when migrating. • Instead, migratory mule deer fine-tuned their migratory behaviour. • Shifts in temporal niches may be underappreciated behavioural strategies.

A framework to interpret co‐occurrence patterns from camera trap data: The case of the gray fox, the bobcat, and the eastern cottontail rabbit in a tropical dry habitat

AbstractIn mammals, ecological interactions are difficult to observe directly, so they are usually inferred from co‐occurrence data. Direct interpretation of co‐occurrence patterns can be complicated since they may be the result of different processes such as habitat selection. We propose a logical framework along with multispecies occupancy models, to distinguish which process or interaction of processes gives rise to co‐occurrence patterns. We also used temporal kernel density estimates to explore the overlap in diel activity patterns, and ecological knowledge of the species as a complement to explain the drivers that generate co‐occurrence. To test our framework, we analyzed three mammal species: the bobcat (Lynx rufus), the gray fox (Urocyon cinereoargenteus), and their potential prey, the eastern cottontail rabbit (Sylvilagus floridanus), in a tropical dry habitat at Tehuacán‐Cuicatlán Biosphere Reserve, Mexico. Data were collected across 67 camera trap stations that operated from February to August 2018. The best‐fitted model described the spatial interaction between U. cinereoargenteus and L. rufus with S. floridanus; in both cases, the occupancy probability of the predatory species was higher in the presence of their prey than in their absence. Additionally, the three species presented a high overlap in their temporal activity patterns. Based on the knowledge of the species' ecology and our results, we identified that trophic interactions could be an important process shaping the co‐occurrence patterns of these species. In short, our framework highlights that it is possible to discern among the processes that influence the co‐occurrence patterns for species with well‐defined ecological roles, such as in our study system.

Rethinking Habitat Occupancy Modeling and the Role of Diel Activity in an Anthropogenic World

AbstractCurrent methods to model species habitat use through space and diel time are limited. Development of such models is critical when considering rapidly changing habitats where species are forced to adapt to anthropogenic change, often by shifting their diel activity across space. We use an occupancy modeling framework to specify the multistate diel occupancy model (MSDOM), which can evaluate species diel activity against continuous response variables that may impact diel activity within and across seasons or years. We used two case studies, fosas in Madagascar and coyotes in Chicago, Illinois, to conceptualize the application of this model and to quantify the impacts of human activity on species spatial use in diel time. We found support that both species varied their habitat use by diel states-in and across years and by human disturbance. Our results exemplify the importance of understanding animal diel activity patterns and how human disturbance can lead to temporal habitat loss. The MSDOM will allow more focused attention in ecology and evolution studies on the importance of the short temporal scale of diel time in animal-habitat relationships and lead to improved habitat conservation and management.

Patterns of spatial distribution and diel activity in carnivore guilds (Carnivora)

In mammalian carnivore guilds (order Carnivora), spatiotemporal partitions play a major role in reducing competitive confrontations and facilitating successful sympatry. Using camera-trapping techniques, the present study aimed to elucidate patterns of spatial distribution and diel activities among medium- and large-sized carnivore species across central Bulgaria. We obtained 3,364 images of nine focal carnivores from 13,988 camera-trapping days between 2015 and 2020. Our findings indicated that the spatial distribution of the focal carnivore guilds varied with changes in altitudinal gradient, ruggedness, and forest-agricultural landscape changes. Specifically, the two largest species, the grey wolf (Canis lupus Linnaeus, 1758) and the brown bear (Ursus arctos Linnaeus, 1758), were found only in the Balkan Mountains, whereas the largest mesocarnivore, the golden jackal (Canis aureus Linnaeus, 1758), was mainly distributed agricultural lowlands. The European wildcat (Felis sylvestris Schreber, 1777) was found in forests inside protected areas, and other mesocarnivores were distributed at intermediate levels between wooded-mountains and agricultural lowlands. Brown bear, golden jackal, and domestic dog (Canis lupus familiaris Linnaeus, 1758) showed cathemeral, crepuscular, and diurnal activity, respectively, whereas the remaining six carnivores showed nocturnal activity in synchrony with their main prey. Our findings indicated that anthropogenic landscape modifications and potential interspecific competition resulted in patterns of spatial distribution and temporal activity in this carnivore guild.

Human recreation impacts seasonal activity and occupancy of American black bears (Ursus americanus) across the anthropogenic-wildland interface

Protected areas serve an important role in wildlife conservation, yet most wildlife occur outside these areas, subject to varying degrees of human disturbance. In the Upper Peninsula of Michigan, American black bears (Ursus americanus), a highly mobile, opportunistic species, are common despite an extensive outdoor recreation industry with the potential to affect black bear spatial and temporal activity. We investigated how environmental and anthropogenic factors influence black bear occupancy, detection, and diel activity patterns across the anthropogenic–wildland interface before and after hibernation. Using 30 camera traps deployed across a rural–wildland interface, we captured black bears at 23 camera sites (~ 77%), which exhibited co-occurrence with humans at 10 sites (~ 33%), revealing that human presence and human population density exert negative effects on black bear seasonal occupancy. Bears were more nocturnal during the hunting season, before hibernation. Human recreational activity increased ~ 38% after hibernation, but bear diurnal activity also increased ~ 36%, except when cubs were present. Our results suggest bears prioritize avoiding humans spatially, rather than temporally, except during the hunting season and when cubs are present. Understanding black bear responses to human recreation patterns and environmental variation is essential for minimizing human-mediated disturbance, and fueling conservation efforts of large, charismatic carnivores.

Diel Rhythm and Thermal Independence of Metabolic Rate in a Benthic Shark.

Biological rhythms that are mediated by exogenous factors, such as light and temperature, drive the physiology of organisms and affect processes ranging from cellular to population levels. For elasmobranchs (i.e. sharks, rays, and skates), studies documenting diel activity and movement patterns indicate that many species are crepuscular or nocturnal in nature. However, few studies have investigated the rhythmicity of elasmobranch physiology to understand the mechanisms underpinning these distinct patterns. Here, we assess diel patterns of metabolic rates in a small meso-predator, the epaulette shark (Hemiscyllium ocellatum), across ecologically relevant temperatures and upon acutely removing photoperiod cues. This species possibly demonstrates behavioral sleep during daytime hours, which is supported herein by low metabolic rates during the day and a 1.7-fold increase in metabolic rates at night. From spring to summer seasons, where average average water temperature temperatures for this species range 24.5 to 28.5 °C, time of day, and not temperature, had the strongest influence on metabolic rate. These results indicate that this species, and perhaps other similar species from tropical and coastal environments, may have physiological mechanisms in place to maintain metabolic rate on a seasonal time scale regardless of temperature fluctuations that are relevant to their native habitats.

Behavioral responses to spatial heterogeneity in endangered Ganges River dolphins (Platanista gangetica gangetica)

Globally, the threat of endangerment and extinction of small cetaceans was highlighted after the recent extinction of the Chinese River dolphin or Baiji (Lipotes vexillifer). Species with a small population size and a limited geographic range, such as Ganges River dolphins (GRD), are more vulnerable to extinction. The social and behavioral needs of cetaceans have been identified as potential factors increasing their vulnerability to human disturbance. However, little is known about how GRD adapt their behaviors and diel activity patterns to spatiotemporal variation. In this paper, we examined the underwater behavior of GRDs in Nepal by collecting echolocation clicks from three spatially stratified habitats in the Sapta Koshi River system over a six-month period. Our research found that GRDs behave differently in response to spatial heterogeneity, indicating diverse environmental requirements for GRD persistence. Behavioral activity and duration varied across habitats but not across time of day, suggesting that GRD behaviors are likely to be regulated by habitat structure regardless of the time of day. However, GRD consistently exhibited nocturnal activity peaks even when diurnal activity varied substantially. This indicates that river dolphins may favor nocturnal refuges as a reaction to human disturbance in highly regulated rivers. Managing human disturbances in conjunction with habitat heterogeneity can improve the persistence of riverine cetaceans. Here, we document behavioral and ecological information pertaining to GRD, which is essential to the formation of river dolphin recovery plans that link ecological perspectives to planning and management.

Camera Trapping Reveals Spatiotemporal Partitioning Patterns and Conservation Implications for Two Sympatric Pheasant Species in the Qilian Mountains, Northwestern China.

Simple SummaryCamera-trapping technology has been widely applied to obtain survey data and enhance understanding of animal ecology. Ground-dwelling pheasants with limited distributions and weak dispersal capacity are prone to extinction due to disturbances and climate change in high-altitude mountain areas. The Qilian Mountains form a global biodiversity hotspot for endemic species and contain crucial areas for ecological and biodiversity conservation. The Blue Eared Pheasant (EP) and Blood Pheasant (BP) are indicator species of the environment and currently occur in the Qilian Mountain National Nature Reserve (QMNNR). Understanding their stable coexistence is key for making informed conservation and management actions. They have similar daily activity patterns but their monthly activity patterns are strikingly different. Both BP and EP prefer forest habitats but BP nests in more dense vegetation cover. Ninety-one percent of BP distribution falls within EP distribution in the QMNNR. Their areas of potential overlap are in the central and eastern parts of the QMNNR, but landscape connectivity is relatively poor. This study further improved the understanding of the basic knowledge of BP and EP coexistence. Conservation actions should give priority to those highly overlapping areas and strengthen forest landscape connectivity, as they provide irreplaceable habitats for threatened Galliformes.Studying the spatio-temporal niche partitioning among closely related sympatric species is essential for understanding their stable coexistence in animal communities. However, consideration of niche partitioning across multiple ecological dimensions is still poor for many sympatric pheasant species. Here, we studied temporal activity patterns and spatial distributions of the Blue Eared Pheasant (EP, Crossoptilon auritum) and Blood Pheasant (BP, Ithaginis cruentus) in the Qilian Mountains National Nature Reserve (QMNNR), Northwestern China, using 137 camera traps from August 2017 to August 2020. Kernel density estimation was applied to analyze diel activity patterns, and the Maxent model was applied to evaluate their suitable distributions and underlying habitat preferences. Eight Galliformes species were captured in 678 detection records with 485 records of EP and 106 records of BP over a total of 39,206 camera days. Their monthly activity frequencies demonstrate temporal partitioning but their diel activity patterns do not. Furthermore, 90.78% of BP distribution (2867.99 km2) overlaps with the distribution of EP (4355.86 km2) in the QMNNR. However, BP manifests a high dependence on forest habitats and shows larger Normalized Difference Vegetation Index (NDVI) values, while EP showed obvious avoidance of forest with NDVI greater than 0.75. Hence, differentiation in monthly activity patterns and partitioning in habitat preference might facilitate their coexistence in spatiotemporal dimensions. Conservation actions should give priority to highly overlapping areas in the center and east of the QMNNR and should strengthen forest landscape connectivity, as they provide irreplaceable habitats for these threatened and endemic Galliformes.

Seasonality and interspecific temporal partitioning in a semiarid grassland bat assemblage of northwestern India

Arid and semiarid environments of the world are characterized by extreme environmental changes that affect the availability of scarce, patchily distributed resources such as water. In response to these changes, animals migrate or partition resources to minimize competition, resulting in temporal patterns within assemblages across multiple scales. Here, we demonstrate that the winter dry season bat assemblage in a semiarid grassland of northwestern India exhibits seasonal changes and temporal avoidance between coexisting species. Using a passive acoustic monitoring framework to quantify activity patterns at different points in the season, we show that members of this assemblage (Rhinolophus lepidus and Tadarida aegyptiaca) exhibit seasonal differences in activity, being more frequently detected in the early and late parts of the dry season, respectively. Other species (Pipistrellus tenuis and Scotophilus heathii) do not exhibit seasonal changes in activity, but structure diel activity patterns, minimizing temporal overlap (and thus competition) at water bodies. These data, some of the first on bats from this region, demonstrate the complex temporal patterns structuring bat assemblages in arid and semiarid biomes. Our results hold promise both in understanding bat behavioral ecology and in long-term monitoring efforts.

Evolution of diel activity patterns in skinks (Squamata: Scincidae), the world's second-largest family of terrestrial vertebrates.

Many animals have strict diel activity patterns, with unique adaptations for either diurnal or nocturnal activity. Diel activity is phylogenetically conserved, yet evolutionary shifts in diel activity occur and lead to important changes in an organism's morphology, physiology, and behavior. We use phylogenetic comparative methods to examine the evolutionary history of diel activity in skinks, one of the largest families of terrestrial vertebrates. We examine how diel patterns are associated with microhabitat, ambient temperatures, and morphology. We found support for a nondiurnal ancestral skink. Strict diurnality in crown group skinks only evolved during the Paleogene. Nocturnal habits are associated with fossorial activity, limb reduction and loss, and warm temperatures. Our results shed light on the evolution of diel activity patterns in a large radiation of terrestrial ectotherms and reveal how both intrinsic biotic and extrinsic abiotic factors can shape the evolution of animal activity patterns.

Diel activity patterns of Garden Dormice (Eliomys quercinus) assessed by camera trap data

Garden Dormouse populations have been decreasing in range and declining in number throughout Europe. Understanding, and therefore preventing, this decline is urgently needed. To devise effective conservation strategies, it is essential to gain knowledge on activity patterns of the target species. Diel activity patterns of Garden Dormice (Eliomys quercinus) were investigated at 25 different sites in Germany. Through an intensive camera-trap survey from March to October 2020 a total of 192,136 pictures were recorded in over 3,682 camera-trap days. The association between activity and environmental parameters, such as habitat (urban vs. natural), the lunar phase and sunrise and sunset, was investigated. Garden Dormice were found to be predominantly nocturnal, but were occasionally active during the day in the summer months. The peak of activity at all sites was shortly before midnight. Garden Dormice in this study did not arrange their activity according to the lunar phase. Daytime activities could be related to the presence of young or the food supply. Weather conditions and cloud cover could explain the small influence of the lunar phase on the animals’ activity. This study revealed the effectiveness of camera trapping to gather information on activity of an elusive small rodent with minimum disturbance to the animals. The data was useful for analyzing and understanding diel activities in different habitats.

Predator niche overlap and partitioning and potential interactions in the mountains of Central Asia

AbstractDirect and indirect interactions among predators affect predator fitness, distribution, and overall community structure. Yet, outside of experimental settings, such interactions are difficult to observe and thus poorly understood. Patterns of niche overlap among predators reflect and shape community interactions and may therefore help elucidate the nature and intensity of intraguild interactions. To better understand the coexistence of two apex predators, snow leopards (Panthera uncia) and wolves (Canis lupus), we investigated their spatial, temporal, and dietary niche overlap in summer in the Pamir Mountains of Tajikistan. We estimated population-level space use via spatial capture–recapture models based on noninvasive genetics and camera traps, diel activity patterns based on camera trap detections, and diet composition from prey remains in carnivore scats, from which we estimated coefficients between 0 and 1 for overlap in space, time, and diet, respectively. Snow leopards and wolves displayed moderate spatial partitioning (0.26, 95% confidence interval [CI]: 0.17–37), but overlapping temporal (0.77, 95% CI: 0.64–0.90) and dietary (0.97, 95% CI: 0.80–0.99) niches. Both predators relied on seasonally abundant marmots (Marmota caudata) rather than wild ungulates, their typical primary prey, suggesting that despite patterns of overlap that were superficially conducive to exploitation competition and predator facilitation, prey were likely not a limiting factor. Therefore, prey-mediated interactions, if present, were unlikely to be a major structuring force in the ecosystem. By implication, carnivore conservation planning and monitoring in the mountains of Central Asia should more fully account for the seasonal importance of marmots in the ecosystem.

Mammals adjust diel activity across gradients of urbanization.

Time is a fundamental component of ecological processes. How animal behavior changes over time has been explored through well-known ecological theories like niche partitioning and predator-prey dynamics. Yet, changes in animal behavior within the shorter 24-hr light-dark cycle have largely gone unstudied. Understanding if an animal can adjust their temporal activity to mitigate or adapt to environmental change has become a recent topic of discussion and is important for effective wildlife management and conservation. While spatial habitat is a fundamental consideration in wildlife management and conservation, temporal habitat is often ignored. We formulated a temporal resource selection model to quantify the diel behavior of 8 mammal species across 10 US cities. We found high variability in diel activity patterns within and among species and species-specific correlations between diel activity and human population density, impervious land cover, available greenspace, vegetation cover, and mean daily temperature. We also found that some species may modulate temporal behaviors to manage both natural and anthropogenic risks. Our results highlight the complexity with which temporal activity patterns interact with local environmental characteristics, and suggest that urban mammals may use time along the 24-hr cycle to reduce risk, adapt, and therefore persist, and in some cases thrive, in human-dominated ecosystems.

Diel activity patterns of two distinct populations of Aedes aegypti in Miami, FL and Brownsville, TX

The diel biting activity of Aedes (Stegomyia) aegypti (L) populations was extensively investigated in the early 1900s to gain more information on the biology of Ae. aegypti, and this information was used to devise effective approaches to controlling populations of this species and protect the human population from widespread arbovirus outbreaks. However, few contemporary studies are available regarding the diel activity patterns of Ae. aegypti. To assess the diel activity patterns of Ae. aegypti in southern Florida and Texas, we conducted 96-h uninterrupted mosquito collections once each month from May through November 2019 in Miami, Florida, and Brownsville, Texas, using BG-Sentinel 2 Traps. The overall diel activity pattern in both cities was bimodal with morning and evening peak activity between 7:00 and 8:00 and between 19:00 and 20:00. There were significant daily, monthly, seasonal, and site-specific differences in activity patterns, but these differences did not affect the overall peak activity times. These differences suggest daily, monthly, seasonal, and site-specific variations in human exposure to Ae. aegypti. Our observations can be used in planning and executing Ae. aegypti vector control activities in southern Florida and southern Texas, specifically those targeting the adult mosquito populations.

Free-ranging livestock altered the spatiotemporal behavior of the endangered North Chinese leopard (Panthera pardus japonensis) and its prey and intensified human-leopard conflicts.

Widespread distribution of livestock in the natural habitats of large carnivores may negatively impact carnivore populations by reducing wild prey availability and increasing human-carnivore conflicts. In this study, we used camera-trapping data collected in the temperate forests of the Taihang Mountains in North China during 2016-2019 to examine whether and how free-ranging cattle affected habitat use and Diel activity patterns of the endangered North Chinese leopard (Panthera pardus japonensis) and its 2 wild prey species, Siberian roe deer (Capreolus pygargus), and wild boar (Sus scrofa). Residents were also interviewed to record livestock depredation events by leopards during 2015-2019. We found that roe deer spatially avoided sites frequented by cattle, but wild boar did not. In the growing seasons, leopards shared habitats with cattle and tended to increase their diurnal activities where cattle were present. All 3 study species exhibited fine-scale spatial-temporal segregation to cattle. Leopards selectively preyed on calves over adult cattle and livestock depredation frequency was positively correlated with the detection rates of cattle and wild prey, but not that of leopard. These findings not only show that through behavioral adaption large carnivores and their ungulate prey may persist under livestock disturbance, but also highlight how important proper livestock management is for conserving North Chinese leopards in this region. To enhance livestock management and mitigate human-leopard conflicts, we recommend specific actions, such as better guarding of free-ranging cattle or adoption of a captive farming system.

A systematic review of factors affecting wildlife survival during rehabilitation and release.

Millions of native animals around the world are rescued and rehabilitated each year by wildlife rehabilitators. Triage and rehabilitation protocols need to be robust and evidence-based, with outcomes consistently recorded, to promote animal welfare and better understand predictors of wildlife survival. We conducted a global systematic review and meta-analysis of 112 articles that reported survival rates of native mammals and birds during rehabilitation and after release to determine intrinsic and extrinsic factors associated with their survival. We assessed survival during rehabilitation and in the short- and long-term post-release, with the hypothesis that survival will vary as a function of species body size, diel activity pattern, trophic level and study location (region of the world). We aimed to determine the direction of effect of these factors on survival to assist in decision-making during triage and rehabilitation. Results showed that mammals and birds were equally likely to survive all stages of rehabilitation, and survival rates varied between locations. Birds in North America had the poorest survival rates post-release, particularly long-term, as did diurnal and carnivorous birds in the short-term post-release. Anthropogenic factors such as motor vehicle collisions and domestic or feral animal attack contributed to morbidity and post-release mortality in 45% (168 of 369) of instances. The reasons for rescue and associated severity of diagnosis were commonly reported to affect the likelihood of survival to release, but factors affecting survival were often species-specific, including bodyweight, age, and characteristics of the release location. Therefore, evidence-based, species-specific, and context-specific protocols need to be developed to ensure wildlife survival is maximised during rehabilitation and post-release. Such protocols are critical for enabling rapid, efficient rescue programs for wildlife following natural disasters and extreme weather events which are escalating globally, in part due to climate change.

Seasonal and diel activities of the Yangtze finless porpoise in natural and highly disturbed habitats: Implications for conservation planning of freshwater cetaceans

Abstract Knowledge of fine‐scale seasonal and diel activity patterns of animals provides insights into habitat utilization dynamics and informs conservation action planning against potential human impacts. Such information is particularly important for riverine cetaceans, such as the Yangtze finless porpoise, which is threatened by habitat loss and disturbances by a variety of human activities. Passive acoustic monitoring (PAM) techniques were used to survey the seasonal and diel activities of the Yangtze finless porpoise in two natural habitat patches of the Anqing Yangtze Finless Porpoise Natural Reserve, and in one highly disturbed area adjacent to the reserve. In the two natural habitat patches, significantly higher detection rates of porpoises were observed during autumn and winter. The detection rates during autumn and winter were significantly higher at night than during daytime, whereas during spring and summer the diel difference in porpoise detection rates was not statistically significant. In the highly disturbed habitat, the porpoise detection rates were significantly lower than those in the two natural habitats. Although seasonal differences in porpoise detection rates were not statistically significant, diel detection rates were significantly different in autumn and winter. Information on seasonal patterns of porpoise activities suggested strengthening monitoring and law enforcement during autumn and winter, during the period in which diel activity patterns implied a potential conservation gap during nighttime. Extremely low levels of porpoise activities in port areas implied an ecological impact of coastal engineering on megafauna viability through the alteration of habitat functionality. To provide information on animal occurrences and activities and to minimize the bias of ‘false‐absence’ from visual surveys, the census survey design should consider both visual and PAM techniques. In seasons when occurrences of river cetaceans and habitat use are increasing, heightened conservation monitoring and law enforcement efforts are required, particularly during nighttime.