Search Results (47)

Understanding how prey and predator species partition activity patterns across time and space is essential for elucidating behavioral adaptation and ecological coexistence. In this study, we examined the diel and seasonal activity rhythms of two sympatric rodent species—Rhombomys opimus (Great gerbil) and Meriones meridianus (Midday gerbil)—and their primary predators, Otocolobus manul (Pallas’s cat) and Vulpes vulpes (Red fox), in a desert-steppe ecosystem on the northern slopes of the Qilian Mountains, China. Using over 8000 camera trap days and kernel density estimation, we quantified their activity intensity and spatiotemporal overlap. The two rodent species showed clear temporal niche differentiation but differed in their synchrony with predators. R. opimus exhibited a unimodal diurnal rhythm with spring activity peaks, while M. meridianus showed stable nocturnal activity with a distinct autumn peak. Notably, O. manul adjusted its activity pattern to partially align with that of R. opimus, whereas V. vulpes maintained a crepuscular–nocturnal rhythm overlapping more closely with that of M. meridianus. Despite distinct temporal rhythms, both rodent species shared high spatial overlap with their predators (overlap index OI = 0.64–0.83). These findings suggest that temporal partitioning may reduce predation risk for R. opimus, while M. meridianus co-occurs more extensively with its predators. Our results highlight the ecological role of native carnivores in rodent population dynamics and support their potential use in biodiversity-friendly rodent management strategies under arid grassland conditions. Full article

The analysis of activity patterns is a valuable tool for understanding the temporal organization of mammal communities, which is determined by biological requirements, resource availability, and competitive pressures both within and between species. Research on this ecological aspect can contribute to the development of effective conservation strategies. Cloud forest is an ecosystem of high biological relevance, as this provides habitat for a wide diversity of species in Mexico, including endemic, emblematic, and threatened taxa. Our main objectives were to analyze mammalian activity patterns and predator–prey relationships in the cloud forest of the El Cielo Biosphere Reserve, Tamaulipas, Mexico. From 2018 to 2020, twenty camera trap stations were installed, and independent photographic records were obtained, divided into 24 one-hour intervals, and subsequently classified as diurnal, nocturnal, crepuscular, or cathemeral. Temporal activity was estimated using circular statistics in RStudio v4.3.1, and activity overlap between major carnivores and their prey was assessed using the ‘overlap’ package in R. A total of 18 medium- and large-sized mammal species were recorded in this study. The activity of four species was seasonally influenced, with a predominantly nocturnal pattern observed during the dry season. The activity overlap analysis revealed potential temporal similarity between predators and their prey. For example, Panthera onca exhibited a high overlap with Mazama temama (Δ = 0.83), Puma concolor with Nasua narica (Δ = 0.91), and Ursus americanus with M. temama (Δ = 0.77). These findings suggest that the activity patterns of certain species can be influenced by seasonality and that large predators may favor specific prey whose activity overlaps with their own. Full article

Understanding predator-prey coexistence mechanisms is essential for conserving endemic species in montane ecosystems. Galliformes serve as critical ecological indicator species, yet their populations are declining globally due to habitat fragmentation and anthropogenic pressures. Elliot’s pheasant (Syrmaticus ellioti, Swinhoe, 1872), a Galliformes species endemic to China, is primarily distributed south of the Yangtze River. However, its coexistence mechanisms with sympatric predators remain undocumented. Here, using six years (2019–2024) of camera-trap data from 90 stations in Jiemuxi National Nature Reserve, Hunan Province, Southwest China, we employed a MaxEnt model and kernel density estimation to investigate spatiotemporal coexistence mechanisms between Elliot’s pheasant and its primary predator, the leopard cat (Prionailurus bengalensis, Kerr, 1792). Across 36,946 camera-days, we obtained 227 independent detections of Elliot’s pheasant and 82 of the leopard cat. Spatial niche analysis revealed high overlap (Schoener’s D = 0.769; Hellinger’s I = 0.952). Both species exhibit similar preferences for main environmental variables. Conversely, significant temporal niche segregation occurred: Elliot’s pheasant displayed diurnal bimodal activity, whereas the leopard cat was strictly nocturnal, resulting in low overlap (Δ₄ = 0.379, p < 0.01). Critically, during Elliot’s pheasant’s breeding season, increased temporal overlap with the leopard cat (Δ₁ = 0.479, p < 0.01) suggested that reproductive behaviors elevate predation risk. Our findings demonstrate that temporal niche partitioning serves as the primary coexistence mechanism, while spatial niche overlap and behavioral adaptations under predation pressure drive dynamic predator-prey interactions. This provides a scientific foundation for targeted conservation strategies and predator management of these threatened Galliformes. Full article

Floating aquatic vegetation and algal blooms are increasing with global warming, potentially reducing UVB exposure and, consequently, vitamin D (vit-D) synthesis in freshwater turtles. Vit-D mediates calcium metabolism and overall health, yet the effects of floating aquatic vegetation on vit-D levels remain unclear, as is whether turtles actively avoid habitats with abundant floating vegetation. Here, we address these questions by quantifying vit-D₃ levels in the blood of adult female painted turtles (Chrysemys picta) exposed to high-vegetation (darker/colder) or clear-water (lighter/warmer) treatments for one month outdoors and one month indoors at a single temperature during late summer and early fall. The observed circulating vit-D₃ levels resembled those reported for other freshwater turtles, declined over time in both treatments, and were marginally lower under high vegetation after 60 days compared to clear water. However, this difference disappeared after correcting for lymph contamination and multiple comparisons, suggesting that perhaps adult females are robust to the effect of floating vegetation, but whether they were buffered by vit-D₃ stores in lipids is unclear. Additionally, in subsequent years, females were exposed to habitat choice experiments and exhibited a strong preference for high floating vegetation over clear water, both as a group (outdoors) and individually (outdoors, and indoors at 21 °C and 26 °C), consistent with known benefits conferred by floating vegetation (food, predator avoidance). While no ill effects of high vegetation nor behavioral avoidance were detected here, longer experiments at different seasons on both sexes and varying ages are warranted before concluding whether painted turtles are truly resilient in their vit-D levels or if, instead, a tradeoff exists between the known benefits of floating vegetation and potential [yet unidentified] detrimental effects (lower dissolved oxygen or vit-D) when vegetation is overgrown for extended periods. Full article

The blue crab Callinectes sapidus Rathbun, 1896 is native to the western coast of the Atlantic Ocean. Although its arrival to the Mediterranean was probably due to ballast water, this species has several characteristics that have enabled it to successfully invade countless localities in the Mediterranean and the Black Sea. Little is known about its feeding habits and ecosystem impacts in the Mediterranean basin. This study aimed to provide information on the natural diet of C. sapidus by comparing the stomach contents of specimens caught in different seasons and habitats of the SE Iberian Peninsula (hypersaline waters in Mar Menor Lagoon and brackish waters in Guardamar Bay). This study also tested whether gender influences prey selection and if ovigerous females exhibit limited feeding activity. Regarding the frequency of occurrence, the results indicated that in Mar Menor Lagoon the most frequently consumed prey were Crustacea (60%), followed by fish (57%) and Mollusca (29%), whilst in Guardamar Bay, Mollusca (40%), sediment (32%), algae (24%) and Crustacea (24%) were dominant. It has been determined that this species predates heavily on Mediterranean shrimp Penaeus kerathurus, an economically important shrimp species in the lagoon area. Analysis using a generalised linear model indicated that sex, season and size class were factors that significantly influenced the stomach content weight. Furthermore, non-ovigerous females had significantly fuller stomachs than ovigerous individuals. Since the population of Callinectes sapidus tends to increase in the Mediterranean basin, monitoring of its feeding ecology is recommended to determine its impact on the ecosystem. Full article

The Spiny-tailed Lizard (Uromastyx aegyptia), a vulnerable species native to the desert and semi-desert regions of the Middle East, remains poorly understood, particularly regarding its daily activity patterns in northern Saudi Arabia. This study, conducted in the Ha’il region, aimed to examine these patterns, assess the influence of soil temperature on activity, and identify potential threats to the species. The results revealed that soil temperature significantly affected the lizard’s activity patterns. During spring, Spiny-tailed Lizards were more active, spending around 25% of the day engaged in various behaviours, while their activity decreased to less than 20% in summer. In autumn and winter, the lizards did not follow a consistent daily activity, becoming active only when surface temperatures exceeded 35 °C. The absence of tracks and sightings in January suggests the species enters a state of complete brumation during this month. While no predation events were recorded via trail cameras, human disturbance from livestock and vehicles was observed in spring and summer. Although the disturbance was minor, reducing this type of human-caused disturbance should be taken into consideration when designing any protection programs. Furthermore, the long-term monitoring of this lizard’s daily and seasonal activity patterns is recommended in order to better understand its adaptability to environmental changes, especially those driven by climate fluctuations. Full article

To achieve the aims of the Convention on Biological Diversity’s 2030 Global Biodiversity Framework, the management of marine areas requires the use of cost- and time- effective monitoring of biodiversity. Marine observation platforms are increasingly used for such monitoring activities. These platforms allow data to be collected from a variety of sensors simultaneously in real-time and in situ, providing the opportunity for both adapting where and when sampling is performed and for using multiple data streams for more comprehensive information to be collected on marine biodiversity. While some recent monitoring activities are following an adaptive sampling approach (in which sampling is adapted to ecological phenomena such as diel vertical migration), most still do not use a data-driven approach (in which multiple data streams are used to inform sampling). In this study, we performed eDNA metabarcoding to monitor the community of copepods found in the high-latitude environment near Trondheim, Norway. We applied an adaptive sampling approach to detect calanoid copepods at seasonally contrasting time points using real-time acoustic sensor data. Acoustic sensor data were used to inform when plankton net samples were collected in a 24 h period, as Calanoid copepods migrate through the water column throughout the day to avoid predation. These results demonstrate how multiple information streams from complimentary monitoring methods can be combined for more robust monitoring of biodiversity by confirming the presence (or absence) of relevant taxa. Full article

Climate change has a profound impact on the phenology and growth of vegetation, which in turn influences the distribution and behavior of animal communities, including prey species. This dynamic shift significantly affects predator survival and activities. This study utilizes the MaxEnt model to explore how climate change impacts the distribution of the North China leopard (Panthera pardus japonensis) in the Ziwuling region of Gansu Province, China. As an endemic subspecies and apex predator, the North China leopard is vital for maintaining the structure and function of local ecosystems. Unfortunately, its population faces several threats, including habitat change, interspecies competition, and human encroachment, all of which are compounded by the ongoing effects of climate change. To assess the requirement and quality of habitat for this species, we conducted a population survey in the Ziwuling area from May 2020 to June 2022, utilizing 240 infrared cameras, which identified 46 active leopard sites. Using the MaxEnt model, we simulated habitat suitability and future distribution under different climate change scenarios based on nine environmental variables. Our results indicate that the population distribution of North China leopards is primarily influenced by the mean diurnal range (Bio2), with additional sensitivity to isothermal conditions (Bio3), temperature seasonality (Bio4), maximum temperature of the warmest month (Bio5), and annual temperature range (Bio7). We also evaluated habitat suitability across three socioeconomic pathways (SSP126, SSP245, and SSP585) for three time intervals: the 2050s (2041–2060), the 2070s (2061–2080), and the 2090s (2081–2100). The findings suggest a significant decline in high-suitability habitat for North China leopards, while areas of medium and low suitability are projected to increase. Understanding these distributional changes in North China leopards will enhance our comprehension of the region’s biogeography and inform conservation strategies aimed at mitigating the impacts of climate change. Full article

Turing’s instability has been widely introduced to explain the formation of several biological and ecological patterns, such as the skin patterning of fish or animals, wings of butterflies, pigmentation, and labyrinth patterns of the cerebral cortex of mammals. Such a mechanism may occur in the ecosystem due to the differential diffusion dispersal that happen if one of the constituent species results in the activator or the prey, showing a tendency to undergo autocatalytic growth. The diffusion of the constituent species activator is a random mobility function called passive diffusion. If the other species in the system (the predator/inhibitor) disperses sufficiently faster than the activator, then the spatially uniform distribution of species becomes unstable, and the system will settle into a stationary state. This paper introduced Turing’s mechanism in our reaction–taxis–diffusion model to simulate the harmful algal bloom (HAB) pattern. A numerical approach, the Runge–Kutta method, was used to deal with this system of reaction–taxis–diffusion equations, and the findings were qualitatively compared to the aerial patterns obtained by a drone flying over Torment Lake in Nova Scotia (Canada) during the bloom season of September 2023. Full article

Temporal and spatial factors regulate the interactions between apex predators, mesocarnivores, and herbivores. Prey adjust their activity patterns and spatial utilization based on predator activities; in turn, predators also adapt to the activities of their prey. To elucidate the factors influencing the daily activity rhythms of animals, 115 camera traps were established from September 2019 to June 2023 to assess the influences of interspecific relationships and seasons on the daily activity rhythms of animals in the southwest mountains of China. The species captured by the cameras included six Carnivora (such as Panthera pardus and Lynx lynx), six Artiodactyla (such as Moschus spp. and Rusa unicolor), one Primate (Macaca mulatta), and two Galliformes (Crossoptilon crossoptilon, Ithaginis cruentus). The results demonstrated that the 15 species exhibited different activity rhythms and peak activities to reduce intense resource competition. There were differences in the species’ activity rhythms in different seasons, with competition among different species being more intense in the cold season than in the warm season. In predation relationships, the overlap coefficient in the cold season exceeded that of the warm season, possibly due to the abundant resources in summer and food scarcity in winter. In competitive relationships, 15 pairs of species exhibited significantly higher overlap coefficients in the cold season compared to the warm season, possibly due to increased demands for energy during the cold period or seasonal changes in predatory behavior. By analyzing the daily and seasonal activity patterns of dominant species in the study area, temporal niche overlaps were established to compare the competition levels between species. These findings indicate that the activity rhythms of the animals in this area not only result from evolutionary adaptation but are also influenced by season, food resources, and interspecific relationships (predation and competition). Thus, efforts should be made to reduce human interference, protect food resources in the winter, and monitor animals’ interspecific relationships to protect animal diversity and maintain the stability of the ecosystem in this biodiversity hotspot in China. Full article

Due to lack of apex predators in human-dominated landscapes, mesopredator relationships are complex and spatiotemporal niche partitioning strategies can vary, especially when seasonal shifts in resource availability occur. Our objective was to understand spatiotemporal niche overlap across seasons among mesopredators inhabiting a barrier island complex. We placed 19 unbaited cameras throughout Fort De Soto County Park, Florida, USA between February 2021 and July 2023. Of six mesopredator species detected, three species had >75 detections during both the wet and dry seasons (coyote, Canis latrans; Virginia opossum, Didelphis virginiana; and raccoon, Procyon lotor). Using general linear mixed models, we determined that during the wet season coyote–raccoon and raccoon–opossum detections were positively associated with each other (p < 0.05). During the dry season, raccoon–opossum detections were positively associated, and opossums were more likely to be detected around mangroves. After calculating coefficients of overlap, we found all three species varied their temporal activity between seasons. During the dry season exclusively, all three mesopredators occupied different temporal niches. The park’s isolated but developed nature has potentially led to a destabilized mesopredator community. Understanding seasonal mesopredator dynamics of Fort De Soto is particularly important because this park supports a high number of nesting shorebirds and sea turtles, which are known food sources for mesopredators. Full article

Sweet pepper is a crop that benefits from phytosanitary treatments with low environmental impact, especially the successful control of pests through the introduction of biological control agents in greenhouses. However, predators that naturally occur in these surroundings often enter greenhouses. The precise roles of these natural predators and their interactions with the introduced predatory insects and mites are often unknown. This study investigated the relationships between Nesidiocoris tenuis, which is naturally present, and Amblyseius swirskii and Orius laevigatus, which are two species of generalist predators released for the control of multiple pests. This study was conducted for two years on 13 commercial sweet pepper crops in various types of greenhouses (tunnels and traditional greenhouses) in Sicily. The environmental complexity value (ECV) for each site was estimated based on 18 points detected around the site according to the different habitats that occurred at each coordinate. The results showed that the occurrence of N. tenuis in greenhouses, independently of their typology (tunnel or traditional greenhouse), was mainly promoted by the greater diversification of habitats immediately surrounding the pepper crops (in a circular area with a diameter of 500 mt), with an increase in its density during the crop season. Moreover, N. tenuis–O. laevigatus’s co-occurrence in flowers suggested that they were not impacted by each other’s presence and that their co-occurrence had a significant effect on pest reduction, although their co-occurrence was density-dependent. As an intraguild predator, N. tenuis competed with O. laevigatus for Frankliniella occidentalis when many predators were present. In addition, N. tenuis also competed with A. swirskii when they both occurred in flowers at a higher density. This study highlights the importance of pepper plant flowers in promoting a higher occurrence of juvenile forms of N. tenuis within flowers. Amblyseius swirskii colonized the plants in 3 weeks, distributing itself almost uniformly over the leaves with a clear control action against not only Bemisia tabaci but also F. occidentalis when present on the flowers. Thus, this concurrent analysis of several commercial pepper sites within the same production area suggests that, even with similar pest control plans, the diverse variability in the presence of natural enemies must be considered when selecting control strategies for pepper crop pests and that N. tenuis, favored by complex surrounding habitats, contributes actively to pest reduction. Full article

Crocodilians are considered to be “ecosystem engineers” because their modification of habitats provides opportunities for feeding, drinking, breeding, and other vital life activities to a wide variety of other animals. One such habitat modification is the construction of nest mounds during the breeding season by most crocodilian species, including American alligators (Alligator mississippiensis). While many reports exist describing wildlife associated with alligator nests, no studies have quantified faunal associates and their corresponding behaviors while visiting nests. To address this data gap, we used automated game cameras to monitor wildlife and their behaviors at alligator nests during the egg incubation period (June–September) in coastal South Carolina, USA (2016–2021). We documented a total of 81 species (79 vertebrates and 2 invertebrates) at 78 alligator nests representing six taxonomic groups, including 48 birds (59.2%), 9 mammals (11.1%), 19 reptiles (23.4%), 3 amphibians (3.7%), 1 malacostracan (1.2%), and 1 insect (1.2%). Collectively, faunal associates primarily used alligator nests for feeding/foraging (51.8%), traveling (29.3%), and loafing (19.9%) and to a much lesser extent basking, burrowing/shelter, breeding, and nesting. However, trends in alligator nest use varied among faunal associate groups (birds, mammals, reptiles, amphibians, etc.), subgroups (e.g., passerines, raptors, wading birds, and waterfowl), and species. Several novel behaviors by some nest associates were also noted during the study, including the first observations of Virginia oppossum (Didelphis virginiana) opening and predating nests, bobcat (Lynx rufus) consuming alligator hatchlings, and Carolina wren (Thryothorus ludovicianus) feeding on the contents of a recently predated alligator egg. The results of this study indicate that a diverse assemblage of vertebrates (and some invertebrates) use alligator nest sites in coastal South Carolina for a variety of life activities during the egg incubation period, and the proportion of the behaviors exhibited varies among animal groups and species. This study provides a first step for investigations regarding the net impacts of alligator nest-faunal associate interactions and ultimately the greater ecological role of alligators and other crocodilians. Full article

The Golden Eagle Aquila chrysaetos (hereafter GE) is one of Europe’s largest avian top predators. The present study recognizes the habitat characteristics and food composition of the GE in Poland. The research was carried out in the Polish part of the Carpathian Mountains. The GEs built nests mainly on old coniferous trees and strongly preferred the Silver Fir Abies alba. On average, within a 5 km buffer around the nest, forests covered about 2/3 of the area, while open land with villages was at 31% and water was about 1%. Birds preferred areas with less forest cover than in the random points, but the nests were significantly further from the countryside than the distance measured for the drawn points distributed in the GEs’ range in Poland. Their diet during the breeding season was assessed by analyzing pellets and food remains. The proportion of birds was 55.7%, mammals was 43.4%, and reptiles was 0.9%. The ten most common prey species included the Domestic Pigeon Columba livia, the Ural Owl Strix uralensis, the Tawny Owl Strix aluco, the Buzzard Buteo buteo, the Roe Deer Capreolus capreolus, the Martens Martes sp., and the Red Fox Vulpes vulpes, which composed 70% of food items. Our results showed that the GE is a top predator, as evidenced by the high share of other predators—both mammal and bird species—in its diet, which constituted about 34% of identified preys. The diet of the studied GE population showed geographical variation, suggesting local adaptations to available prey species. The share of Roe Deer increased from west to east, indicating a higher availability in the less urbanized eastern part of the country. An analysis of general food categories showed that, as latitude increased, the share of captured birds among prey of the GEs declined, while the percentage of forest prey increased. Pigeons were prey of the GEs mainly in the western part of their range. The GEs often captured species with nocturnal activity—owls and martens, which were identified in most of the GEs’ territories. The proportion of mammals in the diet of the GE increased with an increase in the proportion of open areas, while the abundance of birds of prey and owls in the diet correlated with a higher proportion of forests. The greatest threat to Poland’s GE population is the reduction in semi-open areas with low human activity and low human population densities. Full article