Search Results (164)

Investigating biodiversity in remote and harsh environments, particularly in the Southern Ocean, remains costly and challenging through traditional sampling methods such as trawling. Environmental DNA (eDNA) sampling, which refers to sampling genetic material shed by organisms from environmental samples (e.g., water), provides a more cost-effective and sustainable alternative to traditional sampling approaches. To study the biogeographic patterns of two typical mesopelagic fishes, Antarctic lanternfish (Electrona antarctica) and Antarctic deep-sea smelt (Bathylagus antarcticus), in the Cosmonaut Sea in the Indian Ocean sector of the Southern Ocean, we conducted both eDNA and trawling sampling at a total of 86 stations in the Cosmonaut Sea during two cruises in 2021–2022. Two sets of species-specific primers and probes were developed for a quantitative eDNA analysis of two fish species. Both the eDNA and trawl results indicated that the two fish species are widely distributed in the Cosmonaut Sea, with no significant difference in eDNA concentration, biomass, or abundance between stations. Spatially, E. antarctica tended to be distributed in shallow waters, while B. antarcticus tended to be distributed in deep waters. Vertically, E. antarctica was more abundant above 500 m, while B. antarcticus had a wider range of habitat depths. The distribution patterns of both species were affected by nutrients, with E. antarctica additionally affected by chlorophyll, indicating that their distribution is primarily influenced by food resources. Our study provides broader insight into the biogeographic patterns of the two mesopelagic fishes in the remote Cosmonaut Sea, demonstrates the potential of combining eDNA with traditional methods to study biodiversity and ecosystem dynamics in the Southern Ocean and even at high latitudes, and contributes to future ecosystem research and biodiversity conservation in the region. Full article

The blue-eared pheasant (Crossoptilon auritum), a Near Threatened (NT) species endemic to China, is primarily distributed across the northeastern region of the Qinghai–Tibetan Plateau. To bridge the fine-scale spatiotemporal gap in blue-eared pheasant behavioral ecology, this study combines satellite telemetry, movement modeling, and field-based habitat assessments (vegetation, topography, human disturbance). This multidisciplinary approach reveals detailed patterns of their behavior throughout the breeding season. Using satellite-tracking data from six individuals (five males tracked at 4 h intervals; one female tracked hourly) in Wanglang National Nature Reserve (WLNNR), Sichuan Province during breeding seasons 2018–2019, we quantified their home ranges via Kernel Density Estimation (KDE) and examined the female movement patterns using a Hidden Markov Model (HMM). The results indicated male core (50% KDE: 21.93 ± 16.54 ha) and total (95% KDE: 158.30 ± 109.30 ha) home ranges, with spatial overlap among individuals but no significant temporal variation in home range size. Habitat selection analysis indicated that the blue-eared pheasants favored shrub-dominated areas at higher elevations (steep southeast-facing slopes), regions distant from human disturbance, and with abundant animal trails. We found that their movement patterns differed between sexes: the males exhibited higher daytime activity yet slower movement speeds, while the female remained predominantly near nests, making brief excursions before returning promptly. These results enhance our understanding of the movement ecology of blue-eared pheasants by revealing fine-scale breeding-season behaviors and habitat preferences through satellite-tracking. Such detailed insights provide an essential foundation for developing targeted conservation strategies, particularly regarding effective habitat management and zoning of human activities within the species’ range. Full article

This study covers a large area around the Kuril Islands, one of the longest island arcs in the world, crossing several climatic zones, which allows for observations of longitudinal shifts in planktonic species’ ranges following shifts in the boundaries between the climatic zones. We analyzed spatial and vertical changes in the zooplankton community structure and the associated environmental factors from Yuri Island to Onekotan Island both in Pacific and Sea of Okhotsk waters, which are influenced by cold and warm water masses. Species diversity in the Pacific waters was higher than in the Sea of Okhotsk waters, with a peak of diversity recorded from warm waters off the southern Kuril Islands associated with the Soya Current and the Kuroshio Extension. Zooplankton abundance and biomass above the thermocline were higher in the Pacific waters compared to the Sea of Okhotsk area, showing a tendency to increase with higher latitude and lower water temperatures and generally to decline with depth. The water temperature and salinity below the thermocline were the most important explanatory environmental variables responsible for zooplankton abundance variations. The distribution patterns of the large-sized copepods were strongly correlated with temperature and salinity, as well as with dissolved oxygen and chlorophyll a levels. In contrast, small-sized copepods were adapted to or thrived in the areas with elevated temperature and salinity values and a reduced chlorophyll a concentration. Full article

The Pyrenean capercaillie (Tetrao urogallus aquitanicus) is a forest obligate grouse that has experienced a marked population decline in recent decades owing to the lack of optimal habitats. However, the effect of forest structure on potential predators and habitat competitors has not been well-studied. We conducted a camera-trapping study at three conservation areas in Huesca province (northeastern Spain), which were classified as ‘optimal’, ‘favorable’, and ‘unfavorable’ based on habitat suitability for the capercaillie. This study was conducted for 3417 days at a total of 130 camera locations in autumn–winter and spring–summer, capturing 8757 valid photos. In total, 36 different species were recorded. The most frequently detected species were Southern chamois (Rupicapra pyrenaica pyrenaica; 32.6%), roe deer (Capreolus capreolus; 18%), wild boar (Sus scrofa; 9.6%), red squirrel (Sciurus vulgaris; 6.1%), mustelids (5.6%), and red fox (Vulpes vulpes; 4.8%). Capercaillies were photographed in the optimal and favorable habitat areas. Nest predators, such as mustelids and red fox, were more frequently detected in the favorable area during autumn–winter and in the optimal area in spring–summer, while corvids were more frequently detected in the unfavorable habitat area during both periods. No clear pattern was found for wild boar (nest predator and habitat competitor) or cervids (competitors). As capercaillie coexist with a wide range of predators and competitors, and habitat structure may not always explain species relative abundance, factors such as disturbance and food resources should be also taken into account when aiming to develop targeted management for the benefit of the capercaillie. Full article

The Portuguese coast forms a key biogeographic transition zone where co-occurring kelp species show limited vertical overlap. This study aimed to understand whether temperature and light responses help explain the vertical niche differentiation of Laminaria ochroleuca, Saccorhiza polyschides, and Phyllariopsis brevipes. Results revealed that P. brevipes, despite occupying the southernmost range, showed a low thermal tolerance: 27 °C significantly increased respiration rates, indicating metabolic stress, and exposition at 30 °C caused physiological stress. In contrast, L. ochroleuca and S. polyschides exhibited a greater thermal resilience but displayed high light requirements, with evident stress at 30 °C. These results suggest that light availability may play a key role in shaping vertical zonation in a climate warming scenario, with species adapted to low light occupying deeper subtidal zones. S. polyschides, a high light-requiring species, dominates the shallow subtidal region, while L. ochroleuca, also high light-requiring and temperature-tolerant, is abundant in both intertidal pools and shallow subtidal habitats. These findings raise new hypotheses regarding future distribution patterns under climate change: while L. ochroleuca may continue expanding polewards and potentially replace other Laminaria spp. at shallow depths, low-light-adapted, cold-water species may retain a competitive advantage in deeper zones. Full article

Giant clams are ecologically important coral reef animals, with many species facing imminent local extinction. While many regions have undertaken recent assessments of their biodiversity assets, persistent gaps remain even in otherwise well-surveyed areas. This study sought to understand the geographic distribution of smaller-bodied and morphologically similar giant clams, specifically Tridacna maxima and T. noae, in the eastern Indian Ocean. Due to the difficulties in reliably identifying these species using morphological characters, we confirmed species identity and investigated intraspecific variation using sequence data from the mitochondrial cytochrome C oxidase subunit I gene (COI). Seventy whole animal vouchers were newly sampled from a 1500 km span of remote northwestern Australian coastline over a decade, as part of an ongoing coral reef survey expedition of the Western Australian Museum and partners. Tridacna maxima had a limited distribution and was only genotyped from offshore oceanic reefs in the Rowley Shoals and Cocos Keeling Islands. In contrast, T. noae was well established beyond Ningaloo Reef, and was abundant at inshore sites throughout the Pilbara and Kimberley, and even offshore to Ashmore Reef. Phylogeographically, T. maxima did not group with conspecifics from the Western Pacific Ocean, including the east coast of Australia, but instead clustered with individuals from Malaysia, China, Taiwan, and Indonesia; T. noae exhibited a similar pattern. The affinity of Western Australian individuals with representatives from the Indo-Malay region and not eastern Australia will be an important consideration for these commercially important species. Novel haplotypes in both tested species occur in Western Australia. Continued sampling of eastern and central Indian Ocean giant clams, especially to continue to document the range of T. noae, is encouraged to understand connectivity in this basin. Together, these findings contribute to an improved baseline for conservation initiatives of these iconic coral reef animals in Western Australia. Full article

We report a landscape-scale natural experiment that followed the abundance and demography of forest-floor small mammals and the activity of small mustelids over a 4-year period of an extreme heat wave and abundant coniferous cone crops. Deer mice (Peromyscus maniculatus) and southern red-backed voles (Myodes gapperi) are major species in the coniferous forest-floor small mammal community near Summerland in southern British Columbia, Canada. Their major mammalian predators include the short-tailed weasel (Mustela richardsonii), long-tailed weasel (Neogale frenata), and American marten (Martes americana). We evaluated three hypotheses (H) that may explain the changes in these mammals from 2021 to 2024: (H₁) that large coniferous cone crops in 2022 would have generated high populations of forest-floor small mammals in 2023 owing to enhanced reproductive output and overwinter survival; (H₂) that increased activity of mustelids would have followed population increases, resulting in the decline of small mammal prey in 2024; and (H₃) that the widespread occurrence of cone crops in 2022 would also have elicited the same mammalian responses in 2023 at a second study area (Golden, BC) 276 km and three mountain ranges from Summerland. During the summer periods of each year, small mammal populations were monitored by intensive live-trapping, and mustelid presence was measured via an index of activity based on live traps, fecal scats, and predation events. The mean abundance and reproductive performance of the P. maniculatus and M. gapperi populations increased in response to the coniferous seedfall, thereby supporting H₁. The activity of small mustelids responded positively to increased numbers of small mammal prey and potentially acted in a regulatory and top–down function in these communities, and hence partially support H₂. Similar responses at Summerland and Golden indicated that this seedfall event and changes in the mammalian community occurred at a landscape-scale, thereby providing partial support for H₃. Potential differential effects of large seed crops on consumers did not affect the mean abundance patterns for P. maniculatus but apparently reduced this metric for M. gapperi. Heat waves, induced by anthropogenic climate change, may alter the frequency of coniferous masting events, and their effects may temporarily change the number and species of mammalian seed consumers and their predators. Full article

Silverside fishes in Chile, abundant in marine and freshwater habitats, are classified in two genera: Odontesthes and Basilichthys. Both genera have widespread distributions across southern South America, with marine origins. Despite extensive information on Chilean freshwater silversides and their overlapping distributions along a latitudinal gradient, their taxonomy and diversification remain contentious. This study examines the diversity of Chilean silversides using RADseq genomic data from 78 Odontesthes and 60 Basilichthys individuals, covering most of their range. The phylogenetic and structural analyses of approximately 20,000 SNPs reveal some geographic variation but indicate no differentiation between Odontesthes mauleanum and O. brevianalis. The genus Basilichthys, in contrast, presents a disjunct distribution, with populations in coastal rivers of Peru (B. semotilus) that are separated from Chilean populations by the Atacama Desert. Chilean Basilichthys, traditionally classified as B. microlepidotus and B. australis until 2012, also show no genetic differentiation consistent with species boundaries but exhibit latitudinal differences consistent with isolation by distance. The contrasting patterns of genetic differentiation exhibited by species of these genera may be explained by the more frequent exchange with marine species for Odontesthes that do not occur in Basilichthys, in addition to the recent geological history of glaciations affecting the southern range of their distribution. Full article

Agroforestry systems are essential in sustainable land use in the face of the growing global food demand and climate change. The southern region of Bahia, Brazil, is one of the places in the world where the tree species is particularly in abundance, primarily in cocoa agroforestry systems, contributing to biodiversity conservation. Understanding their reproductive patterns is crucial for the survival and sustainability of these trees. This study dealt with Lecythis pisonis (Sapucaia) trees by applying microsatellite markers for mixed-mating mode and paternity analyses for pollen dispersal. In particular, it was found that Lecythis pisonis offspring are produced through outcrossing, as the case may be, while random crossings and no nearby tree fertilization are the remaining factors that play a crucial role in myriad genetic diversity inversions. This phenomenon was indicated by paternity in nine offspring, with full siblings being from the same parents. The average distance of pollen flow was 6 km, which is why the pollinator, the bee Xylocopa frontalis, has a flight range aligning with distance. These data show the influence of habitat fragmentation, the function of Cabruca, and the conservation strategy. Full article

Holoparasitic plants of the genus Cuscuta are generally considered prominent agricultural pests. In addition to their negative economic effect on agriculture and their impact on natural plant societies, they have also been long known in East Asian as medicinal plants with beneficial properties. This underlines the fact that Cuscuta spp. are particularly rich in specialized metabolites, flavonoids, alkaloids, and cumarines, among others. In addition to several well-characterized species, most of the species variety within the genus remains largely unstudied. In the present study we aimed to compare the flavonoid profiles of natural populations of two of the most abundant Cuscuta species in Bulgaria—the native C. epithymum, and the naturalized C. campestris. Based on HPLC-MS/MS analysis, a total of 13 polyphenolics compounds were annotated, with hyperoside and isoquercitrin being some of the most abundant. Some notable differences were found, like the complete absence of dicaffeoylquinic acid in C. campestris, and kaempferol-3,7-O-diglucoside and kaempferol 3-O-β-(6′′-O-trans-p-coumaroyl)-glucopyranoside in C. epithymum. The population of the two species clustered separately from each other, with some variations, but with no clear pattern of dependence on the locality or host species. Based on the results it can be concluded that flavonoids may be used as chemotaxonomical markers within the genus, showing that even in different climatic conditions and different host ranges, the two studied species clearly differed from each other. Also, their rich content emphasizes the potential of these parasites as a source of bioactive compounds. Full article

Jellyfish blooms are dynamic events driven by environmental and anthropogenic factors. This study reports the first documented bloom of the cannonball jellyfish (Stomolophus sp.) in Venezuelan waters, observed between March and April 2024 along approximately 120 km of coastline. Reports from anglers and divers confirmed high jellyfish abundances (~3 ind. m⁻³) across multiple sites. Environmental analyses suggest that fluctuations in sea surface temperature, increased chlorophyll a concentrations, and high precipitation in the preceding months may have triggered strobilation and subsequent bloom formation. However, the polyps have not yet been observed in the field, and advective movement from other locations cannot be ruled out. Given the commercial importance of Stomolophus spp. in neighboring regions, this record underscores the need for continued monitoring to assess potential range expansions and their ecological and socio-economic impacts. Additionally, the emergence of this bloom raises questions about the species’ distribution patterns, potential establishment in Venezuelan waters, and possible implications for local fisheries. Our findings contribute to the broader understanding of gelatinous zooplankton dynamics in the Caribbean Sea and provide baseline information for future ecological assessments and fisheries management strategies. Further studies, including genetic analyses, are needed to confirm species identity and investigate the drivers behind this unprecedented bloom. Full article

Tub gurnard, Chelidonichthys lucerna, is a common and widely distributed species throughout the Sea of Marmara (SoM). The knowledge on the spatial distribution of tub gurnards in the SoM in association with environmental factors is limited. The relationship between tub gurnard abundance and environmental variables (depth, temperature, dissolved oxygen, pH, and spatial variability) in the eastern Sea of Marmara (ESoM) was analyzed by means of the generalized additive model (GAM) in the present study. Additionally, the size distribution of tub gurnards was examined in relation to depth and season. Data were collected over an 11-year sampling period (2014–2024) within the scope of scientific demersal trawl surveys in the ESoM. The GAM results revealed that while all the analyzed variables influenced the spatial distribution patterns of tub gurnards, temperature and depth were the most significant contributors in the ESoM. The abundance of tub gurnard exhibited a strongly nonlinear relationship with the explanatory covariates. Regarding the depth distribution patterns of tub gurnards in association with fish size, statistical tests showed significant differences between the size frequency distributions in the two depth ranges, of which the mean total lengths were 24.1 ± 6.90 and 23.5 ± 4.27 cm for depths >80 and <80 m, respectively. A preferred depth was obviously expressed, with tub gurnards moving into deeper water as they grew larger. The mean sizes (range) were 23.56 ± 6.92 cm (13.1–69.6 cm), 24.8 ± 5.35 cm (17.1–58.5 cm), 24.9 ± 8.14 cm (13.1–56.5 cm), and 23.0 ± 5.22 cm (14.2–46 cm) for winter, spring, summer, and autumn, respectively. Therefore, the observed distribution patterns highlight the influence of environmental factors on the abundance of tub gurnard species. Full article

The Asiatic lion (Panthera leo leo), a flagship species of conservation significance, has expanded its range beyond the Gir protected areas into multi-use landscapes, including the coastal regions of Saurashtra, Gujarat, India. This study examines the dietary patterns of Asiatic lions in this unique coastal region. Using scat analysis, we identified the prey species consumed and quantified their contributions to the lions’ diet. Results indicate that the lions predominantly consumed wild prey, such as Boselaphus tragocamelus, Sus scrofa, and Axis axis, which together constituted 64% of their diet. Domestic prey contributed 31%. In terms of biomass, wild prey accounted for 70%, with Boselaphus tragocamelus alone contributing 51%. The dietary niche breadth, calculated using Levin’s index, was 0.36, suggesting a relatively specialized diet. This study underscores the importance of prey abundance and habitat structure in shaping lion predation patterns. Lions’ reliance on wild prey, particularly Boselaphus tragocamelus and Sus scrofa, highlights their crucial role in the coastal region. Additionally, the inclusion of domestic prey, such as feral cattle, may reflect their high availability and reduced anti-predator behaviors. These findings emphasize the need for robust prey population monitoring and habitat conservation to ensure the long-term survival of Asiatic lions in the coastal region. Full article

Montmorillonite (Mont) is a natural two-dimensional material with a 2:1 layered silicate crystal structure. It possesses abundant surface groups, cation exchange capacity, and adsorption performance. In addition, it has other advantages such as abundant reserves, environmental friendliness, strong mechanical stability, and a large specific surface area. As such, it shows excellent potential for application in environmental remediation. In the following paper, we focus on the removal of TCS (triclosan) from an aqueous environment by utilizing montmorillonite-supported bimetallic Fe/Ag particles. We use scanning electron microscopy, X-ray diffraction patterns, Fourier-transform infrared spectra, and specific surface area to analyze the structure, morphology, and composition of these nanocomposites. The effects of the pH, different materials, contact time, and different initial concentrations on the degradation efficiency of TCS were studied systematically. Based on the results of our study, montmorillonite-supported bimetallic Fe/Ag nanoparticles (Fe/Ag-Mont) should be categorized as a type of mesoporous material of high uniformity because the pore size of all its catalysts ranges from 10 to 20 nm, and they are well-distributed. The Si-O stretching vibrations of montmorillonite can be changed by adding Fe/Ag. We found that Fe or Ag combined with -O to form a new bond and interacted with Si-O, and the incorporation of Fe/Ag-Mont nanoparticles removed TCS with better reduction rates. By enhancing reduction capacity, the pH was below 4 due to H• species generation by Fe/Ag. H• was the main factor enhancing the redox reaction in reducing TCS. The pH controlled the competition between Fe corrosion and silver formation, which enabled the system to self-regulate. In addition, this study provided a suitable method of efficiently synthesizing clay-supported bimetallic nano-system materials for reduction. Full article

Based on the data from a continuous fishery resource survey conducted in the Shandong province area of the Yellow River from the summer and autumn of 2022 to the winter and spring of 2023, this study constructed fish biomass particle-size spectra. It compared and analyzed the differences in the characteristics of the fish biomass particle-size spectrum parameters across four different seasons in various survey areas. The results indicated that the fish biomass particle-size spectra in the Shandong province area of the Yellow River exhibited significant seasonal and spatial variations. Overall, the shape of the Sheldon-type biomass particle-size spectra across the four seasons showed a unimodal pattern. The peak values in spring and summer ranged between 32–64 g, while in autumn, it reached 64–128 g, and in winter, it was 1024–2048 g. The dominant species shifted from small individuals in spring and summer to larger individuals in autumn and winter. The fitted curves of the standardized biomass particle-size spectra for the four seasons displayed a dome-shaped parabola, generally arranged from high to low in the biomass particle-size spectra lines from spring to winter, with winter experiencing the least external disturbance. In terms of the regional distribution, the peak particle-size classes for fish in the areas of Gaocun, Dong’a, and Gaoqing all corresponded to the particle-size class of 16–32 g, predominantly featuring small fish species such as Carassius auratus and Pseudobrama simoni. In contrast, the peak particle-size class in the estuarine waters corresponded to 512–1024 g, mainly comprising larger fish species like Cyprinus carpio, Hypophthalmichthys molitrix, and Liza haematocheila. The differences in the standardized biomass particle-size spectra among the four regions were not significant, but the curvature of the estuarine waters was the highest, indicating the least external disturbance. The abundance–biomass comparison (ABC) curve suggested that the fish community in the Shandong province area of the Yellow River is in a severely disturbed state. Full article