Population Dynamics Of Species Research Articles

Forecasting the Dynamics of Summer Phytoplankton Species based on Satellite Data Assimilation Methods

Introduction. Mathematical tools integrated with satellite data are typically employed as the primary means for studying aquatic ecosystems and forecasting changes in phytoplankton concentration in shallow water bodies during summer. This approach facilitates accurate monitoring, analysis, and modeling of the spatiotemporal dynamics of biogeochemical processes, considering the combined effects of various physicochemical, biological, and anthropogenic factors impacting the aquatic ecosystem. The authors have developed a mathematical model aligned with satellite data to predict the behavior of summer phytoplankton species in shallow water under accelerated temporal conditions. The model describes oxidative[1]reduction processes, sulfate reduction, and nutrient transformations (phytoplankton mineral nutrition), investigates hypoxia events caused by anthropogenic eutrophication, and forecasts changes in the oxygen and nutrient regimes of the water body.Materials and Methods. To simulate the population dynamics of summer phytoplankton species correlated with satellite data assimilation methods, an operational algorithm for restoring water quality parameters of the Azov Sea was developed based on the Levenberg-Marquardt multidimensional optimization method. The initial distribution of phytoplankton populations was obtained by applying the Local Binary Patterns (LBP) method to satellite images of the Taganrog Bay and was used as input data for the mathematical model.Results. Using integrated hydrodynamic and biological kinetics models combined with satellite data assimilation methods, a software suite was developed. This suite enables short- and medium-term forecasts of the ecological state of shallow water bodies based on diverse input data correlated with satellite information.Discussion and Conclusion. The conducted studies on aquatic systems revealed that improving the accuracy of initial data is one mechanism for enhancing the quality of biogeochemical process forecasting in marine ecosystems. It was established that using satellite data alongside mathematical modeling methods allows for studying the spatiotemporal distribution of pollutants of various origins, plankton populations in the studied water body, and assessing the nature and scale of natural or anthropogenic phenomena to prevent negative economic and social consequences.

Global Potential Geographic Distribution of Anthonomus eugenii Under Climate Change: A Comprehensive Analysis Based on an Ensemble Modeling Approach.

Climate warming is affecting the ranges and population dynamics of invasive species, including insects, which have become a global problem, causing biodiversity declines and agricultural economic losses. Anthonomus eugenii as an important invasive pest on pepper is now mainly located in the USA and Mexico. However, the global potential geographic distribution (PGD) of A. eugenii with climate change remains unknown, which makes it difficult to monitor and control. In this study, based on the global distribution areas and important environmental variables, we constructed an ensemble model to predict the global PGD of A. eugenii under the current climate and three climate scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5) in the 2030s and 2050s. The mean true skill statistics (TSS) and the area under the receiver operating characteristic curve (AUC) of the EM were 0.825 and 0.988, respectively, indicating that the EM was reliable. The mean temperature of the driest (bio9) and wettest (bio8) quarter and precipitation of the coldest quarter (bio19) were the most important environmental variables affecting the PGD of A. eugenii. Under the current climate, the PGD of A. eugenii was mainly concentrated in southern North America and central South America. The suitable areas of A. eugenii could increase significantly, reaching the maximum under SSP5-8.5 in the 2030s, approximately 1911.7 × 104 km2. Moreover, the distribution centroid would shift to higher latitudes with global warming. It also had the potential invasion risk in Russia, China, the Republic of the Congo, and Romania, which should enhance quarantine control and early warning.

The impact of resources availability on phytophthora population dynamics and ecosystem health

The relationship between resource availability and the population dynamics of Phytophthora species plays a critical role in shaping ecosystem health. Phytophthora is a genus of oomycetes that known for their impact on agricultural and natural ecosystems. Resource availability, encompassing both abiotic factors like soil nutrients and moisture, and biotic factors such as host plant density and diversity, influences Phytophthora populations and their pathogenicity. This interaction often results in complex feedback loops where shifts in resource availability can worsen or mitigate the spread of Phytophthora infections. For instance, high soil moisture levels and nutrient availability can enhance pathogen growth and sporulation, leading to increased disease incidence and severity. Conversely, resource limitations may suppress pathogen populations but can also lead to reduced host plant vigor, indirectly affecting ecosystem health. Understanding these dynamics is crucial for effective management strategies, as it helps in predicting disease outbreaks and implementing measures to sustain ecosystem functionality and resilience. This study highlights the need for integrated approaches that consider both the ecological impacts of Phytophthora and the broader implications for ecosystem health, emphasizing the importance of resource management in mitigating pathogen-related disruptions.

Morphological Characteristics and Annual Population Dynamics of Microcystis (Cyanobacteria) in Nanwan Reservoir (Xinyang, China)

Microcystis, a key genus of bloom-forming cyanobacteria in freshwater ecosystems, has garnered significant research interest due to its species diversity and population dynamics. This study investigated the water profiles and Microcystis populations at six stations in the Nanwan Reservoir (Xinyang, China) throughout 2022 to elucidate the morphological characteristics of Microcystis, analyze its population density patterns, and identify key environmental factors influencing its dynamics. The reservoir was classified as mesotrophic during most of the study period. Seven common Microcystis species were identified, including M. botrys, M. smithii, M. wesenbergii, M. firma, M. novacekii, M. aeruginosa, and a species suspected to be M. flos-aquae. The spatial and temporal distribution analyses revealed a bimodal fluctuation in Microcystis densities, with a monthly occurrence across stations except in August. The highest density, 1.71 × 107 cells/L, was recorded in May, while the lower densities were observed from July to September. The Mantel test results indicated that the nitrogen levels, particularly NO3−-N, were the primary factors influencing the Microcystis density. Additionally, both the reservoir bays and dam areas exhibited a high risk of Microcystis blooms. Effective management of nitrogen inputs, enhanced monitoring, and appropriate gate operations are recommended to mitigate the risk of Microcystis blooms in the Nanwan Reservoir.

Use of water bodies by the collared peccary Pecari tajacu (Artiodactyla: Tayassuidae) in the Maya Forest, Mexico

Water availability is a critical factor influencing the abundance and distribution of species, particularly in environments where it is scarce. This study aimed to assess the visit frequency index (VFI, a proxy for abundance) and activity patterns of the collared peccary (Pecari tajacu) at various natural and artificial water sources in the Calakmul Biosphere Reserve, Campeche, Mexico. We employed camera trapping from January to December 2020, monitoring 30 water bodies: 10 artificial water troughs, 10 natural aguadas (depressions where rainwater accumulates), and 10 sartenejas (erosion-formed cavities in rocky soils that collect rainwater). Our results indicate that P. tajacu utilized sartenejas (VFI = 29.92 records/trap-days) and water troughs (VFI = 22.08 records/trap-days) more frequently than aguadas (VFI = 6.54 records/trap-days). The daily activity patterns of P. tajacu were predominantly diurnal at water troughs and aguadas, while activity at sartenejas was cathemeral. Despite being a species known for its reliance on water sources, the VFI recorded in this study was lower compared to previous studies. This decrease is likely linked to increased water availability in the region during the study period, which may have led to avoidance behavior by P. tajacu due to the presence of white-lipped peccaries (Tayassu pecari) and predators such as jaguars (Panthera onca) and pumas (Puma concolor), which were more abundant at the aguadas. Considering the rapid progression of climate change and the increasing occurrence of extreme drought and rainfall events in the region, it is crucial to deepen our understanding of the relationships between water availability and the population dynamics of wildlife species. This knowledge will be essential for developing strategies to mitigate the adverse effects of climate change on biodiversity.

Individual Choices of Wintering Areas Drive Adult Survival Heterogeneity in a Long-Lived Seabird.

Seasonal migration has evolved as an adaptation for exploiting peaks of resource abundance and avoiding unfavourable climatic conditions. Differential migratory strategies and choices of wintering areas by long-distance migratory species may impose varying selective pressures and mortality risks with fitness consequences. Recently developed tracking technologies allow wintering movements of migratory species to be studied. However, these technologies typically involve a limited number of tracked individuals, which gives low statistical power for any robust estimate of survival probabilities. Additionally, when utilising geolocators, data become accessible only upon individual recapture, presenting a potential source of bias. We used multievent modelling to include information of 147 identified wintering tracks in the analysis of 1104 long-term individual capture histories (2000-2022) of migratory seabird Calonectris diomedea and then test if individual preferences for wintering areas may drive heterogeneity in adult survival. We also examined individual fidelity to wintering areas and tested if climatic and oceanographic conditions, as represented by the wNAO and SOI climatic indices, influenced survival and fidelity. The probability of fidelity to a wintering area was ca. 0.79. Annual changes between areas were influenced by environmental variability driven by the wNAO. Survival probability was influenced by the SOI and differed between wintering areas; these differences coupled with high wintering site fidelity, generated individual heterogeneity in adult survival. Our study reveals that, over the last two decades, some individuals wintered in less suitable areas, with nonnegligible consequences on adult survival, the parameter to which the population growth rate is most sensitive in long-lived species. Winter oceanographic conditions such as stormy weather or the proximity to upwellings probably play a relevant role in driving survival heterogeneity. Further research is needed to enhance our understanding of how the interlinked effects of climate, local selective pressures and individual condition shape population dynamics in migratory species.

Morphological and morphometric investigations on testate amoebae from Mongolia with descriptions of a new genus and four new species.

Testate amoebae are a polyphyletic and highly diverse group of unicellular protists, inhabiting various habitats and successfully used as indicators of property of environmental variables, providing information on hydrology, pH and pollution of ecosystems. However, despite numerous studies, there is still a lack of data regarding their species diversity, geographical distribution and population dynamics in various habitats from previously unexplored or poorly investigated regions such as Mongolia. In this study, we describe the morphology and morphometry of a new genus and four new species: Armatura murmillo gen. nov., sp. nov., Trinema lenticularis sp. nov., T. parmularius sp. nov. and T. scutarius sp. nov., derived from peat cores extracted from two fens in northern Mongolia. We provide one of the first case studies of testate amoebae from Mongolia, documenting 64 taxa. We also provide information on the morphology and variability of four lesser known species: Centropyxis lapponica, Hyalosphenia insecta, Pyxidicula ornata and Schoenbornia smithi.

Population dynamics of sympatric Phortica spp. and first record of stable presence of Phortica oldenbergi in a Thelazia callipaeda-endemic area of Italy

BackgroundFive species of the Phortica genus (Diptera: Drosophilidae) are known in Europe and the Middle East. Among these, Phortica variegata and Phortica okadai are better known for their role as vectors of the zoonotic eyeworm Thelazia callipaeda. Other species, such as Phortica semivirgo and Phortica oldenbergi, have been studied less. Given the paucity of data about these Phortica spp. vectors, we explored the population dynamics and ecology of Phortica spp. in an area highly endemic for T. callipeada (Manziana, Rome, Central Italy).MethodsPhortica spp. flies were collected over a 3-year period (2018–2020) during their active season (April–October) with a sweep net while hovering around fermenting fruits or a human operator acting as baits. Collected flies were morphologically identified and tested for a T. callipeada infection and for the presence of Wolbachia, by polymerase chain reaction (PCR). Population dynamics of species collected was associated to environmental drivers through generalized additive models.ResultsOf the 5564 flies collected, 90.8% were P. variegata, 9.1% were P. oldenbergi, 0.05% were P. semivirgo, and one specimen was P. okadai. Only P. variegata scored molecularly infected with T. callipeada throughout the 3-year sampling period (1.8%). Phortica oldenbergi, observed consistently during the entire sampling period, exhibited a marked preference for fruit traps, contrasting with the lachryphagous activity of P. variegata. Analysis of environmental drivers of P. oldenbergi and P. variegata population dynamics indicated temperature, wind speed, and pressure as significant factors. In addition, Wolbachia pipientis endosymbiont was detected in P. oldenbergi and P. okadai.ConclusionsFor the first time, this study analysed several ecological aspects of Phortica species coexisting in a T. callipeada endemic area, highlighting different behaviors in the same environment and their vectorial role. Notably, this is also the first report of the presence of P. oldenbergi in Italy and P. okadai in Europe, underscoring the importance of extensive sampling for detecting potential vectors and alien species with direct implications for vector-borne disease epidemiology.Graphical

A Study on Future Population Dynamics of Indigenous Earthworm Species in Golaghat District of Assam, India

This study presents a pioneering exploration into the population dynamics of indigenous earthworm species in the Golaghat district of Assam, India, through the lens of mathematical modeling. Recognizing the integral role of earthworms in enhancing soil productivity and ecosystem health, we embarked on a detailed longitudinal analysis spanning from 2018 to 2023 to assess their population trends across different seasons and subdivisions within the district. Utilizing the principles of Mathematical Biology, we employed the Malthus Growth model and the Logistic Growth model to estimate future population trajectories of earthworm species, integrating biological insights with mathematical rigor. Our methodology, combining extensive field data collection with sophisticated mathematical modeling, provides a replicable framework for similar ecological studies. This study contributes to the growing field of Mathematical Biology, offering a novel approach to understanding the complex interactions within ecosystems and the impact of environmental changes on key species. The outcomes offer valuable insights into sustainable agricultural practices and biodiversity conservation in tropical and subtropical regions, emphasizing the critical role of indigenous earthworm species in maintaining soil health and ecosystem services. Our findings reveal significant seasonal variations and highlight the resilience of these species in the face of ecological changes. The models suggest distinct population growth patterns, with the Logistic model providing a more realistic projection considering environmental constraints and resource availability. The bifurcation diagram is drawn for the Logistic map that presents the phenomena inside the chaotic region.

Complex of codling moths in orchard agrocenoses of North-West Russia

The purpose of this work was to study the species composition and population dynamics of some codling moths (Insecta: Lepidoptera: Tortricidae) in orchards of Velikoluksky district of the Pskov region, Pushkinsky district of St. Petersburg and Luga district of the Leningrad region during the vegetation seasons in 2022–2023. The results of study of the range expansion, the number of generations of dominant pest species, and the influence of meteorological factors on the moth flight are presented. The pheromone monitoring was used in this work, i.e. pheromone traps with synthetic sex pheromones of five moth species: Cydia pyrivora (Danil.), Cydia pomonella L., Pammene rhediella (Clerck), Grapholita funebrana Tr. and Grapholita molesta (Busck). As a result of the research, C. pyrivora was firstly discovered in the Pskov region, being absent in traps in the Leningrad region. P. rhediella was found only in the experimental orchard of the Pushkinsky district, C. pomonella and G. funebrana were mass pest species in two regions, and G. molesta was not registered.

Influence of Longitudinal Fragmentation on Length–Weight Relationships of Fishes in the Someșul Cald River, Romania

Romania has a rich hydrographic network, which permitted the construction of over 80 large dams on its water courses, estimating a number between 545 and 674 hydropower plants that were either built or were in a different construction stage on the rivers of Romania in 2021. These hydropower plants were often built outside specific legislation regarding ecological impacts, especially before 1990. Longitudinal fragmentation of rivers causes severe ecological impacts on biodiversity, food chains, and nutrient cycles. Someșul Cald River is the main tributary of Someșul Mic River, the most important water source for the northwestern region of Transylvania. On its course, several dams and reservoirs were built from 1968 to 1980 for electricity production and population freshwater supply. The present study aimed to analyze the length–weight relationships (LWRs) and condition factors occurring in the longitudinally fragmented Someșul Cald River. The LWRs, relative condition factor Kn, and Fulton condition factor K were determined based on total length and wet body weight. Comparisons of LWRs, Kn, and K across river sections constrained by dams showed that some fish species exhibited similar growth patterns and physiological conditions, while others differed significantly. Freshwater fish physiology is altered by longitudinal fragmentation, both natural and artificial. Barriers such as dams influence the energy gradient, limiting feed availability and, consequently, the life history of fish species. Long-term management plans regarding conservation should take into consideration existing fish species population dynamics, along with their physiological and somatic status.

Body size and early marine conditions drive changes in Chinook salmon productivity across northern latitude ecosystems.

Disentangling the influences of climate change from other stressors affecting the population dynamics of aquatic species is particularly pressing for northern latitude ecosystems, where climate-driven warming is occurring faster than the global average. Chinook salmon (Oncorhynchus tshawytscha) in the Yukon-Kuskokwim (YK) region occupy the northern extent of their species' range and are experiencing prolonged declines in abundance resulting in fisheries closures and impacts to the well-being of Indigenous people and local communities. These declines have been associated with physical (e.g., temperature, streamflow) and biological (e.g., body size, competition) conditions, but uncertainty remains about the relative influence of these drivers on productivity across populations and how salmon-environment relationships vary across watersheds. To fill these knowledge gaps, we estimated the effects of marine and freshwater environmental indicators, body size, and indices of competition, on the productivity (adult returns-per-spawner) of 26 Chinook salmon populations in the YK region using a Bayesian hierarchical stock-recruitment model. Across most populations, productivity declined with smaller spawner body size and sea surface temperatures that were colder in the winter and warmer in the summer during the first year at sea. Decreased productivity was also associated with above average fall maximum daily streamflow, increased sea ice cover prior to juvenile outmigration, and abundance of marine competitors, but the strength of these effects varied among populations. Maximum daily stream temperature during spawning migration had a nonlinear relationship with productivity, with reduced productivity in years when temperatures exceeded thresholds in main stem rivers. These results demonstrate for the first time that well-documented declines in body size of YK Chinook salmon were associated with declining population productivity, while taking climate into account.

Long‐term tracking captures the timing of ontogenetic niche shifts in northeast Pacific white sharks

AbstractOntogenetic changes in area use, habitat use, and trophic interactions play an important role in the ecology, demography, and ultimately population dynamics of many species. Assumed to be driven by shifting life‐history requirements, trophic niche shifts in white sharks (Carcharodon carcharias) are well documented, but the timing of the spatial niche shift that is hypothesized to occur with the trophic niche shift remains poorly understood. To document how fine‐scale area use varies as sharks age and the timing of the ontogenetic spatial shift of this top predator, we tracked individual white sharks tagged as young‐of‐the‐year or young juveniles over multiple years. Using data from juvenile white sharks detected over multiple years in a nursery habitat with a high‐density receiver array, we found no difference in area use with age. However, using a coast‐wide receiver array including nursery and adult habitat, we found the probability of detecting a juvenile white shark in nursery habitat decreased with age, with a concurrent increasing probability of detection in adult habitat. As the conservation and management of this species relies on understanding nursery habitat use and age‐related movements, data presented here address an important knowledge gap for the understudied juvenile to subadult life stages and the ontogenetic habitat shift of this species.

Is the population of kingfish (Scomberomorus commerson) in the northern Persian Gulf really under pressure from overfishing?

AbstractQuantifying the population dynamics of marine species is difficult when good, comprehensive data are not available. We sought to determine if the kingfish Scomberomorus commerson stock in the Persian Gulf was overfished. The ICES data‐limited assessment framework was used to provide precautionary advice, with a 20% decrease advised in situations where only catch or bycatch data were available. The length‐based Bayesian biomass (LBB) was used to model fork length from landing records of licensed fishers in the Khuzestan Province during 2002–2018, which had increased despite sought being overexploited. Most kingfish were immature and smaller than optimum length of the catch (Lc‐opt = 88 cm) and optimum length (Lopt = 104 cm). Relative biomass (B/Bmsy) ranged 0.62–0.66 and exceeded 0.5. The B/Bmsy ratio (1.25) was >1.1. The stock appeared to be healthy and exploitable, but wide confidence intervals of the B/Bmsy ratio complicated interpretation of stock status. The kingfish stock appeared to use waters of the study area as a spawning and nursery ground, so many young immature individuals were present. If current exploitation of young individuals continues, this the stock will eventually be overfished. Long‐term increases in the catch of young immature kingfish can have a side effect on stock maturation and recruitment. We recommend that the mesh size of fishing gear be selected based on optimum length, to enhance economic, and commercial viability of the kingfish fishery.

Combined effects of food quality and temperature on competitive interactions between small- and large-bodied cladoceran species

Competition is one of the main drivers of population dynamics of cladoceran species. According to the Size Efficiency Hypothesis, large-bodied cladocerans are superior competitors over small-bodied species because they are more effective filter-feeders and can consume a wider size spectrum of food particles. However, we hypothesized that food quality in terms of phosphorus (P) and/or polyunsaturated fatty acid (PUFA) content can alter competitive interactions, and these potential effects can be modified by temperature. Since large-bodied cladocerans are more vulnerable to poor food quality and are regarded as less adaptive to high temperatures, we hypothesized that large-bodied species would be superior competitors at low temperature and/or high food quality, while small-bodied cladocerans would be competitively superior at enhanced temperature and/or poor food quality. To verify this hypothesis, we conducted laboratory experiments with the small-bodied D. longispina and large-bodied D. magna fed with three different types of food: (1) P-poor and PUFA-rich green algae (low phosphorus or LP-treatment), (2) PUFA-poor-cyanobacteria treatment (CYANO) and (3) P-rich and PUFA-rich green algae (high phosphorus or HP-treatment) at 18°C and 24°C. We found that D. magna had a stronger suppressive competitive effect on D. longispina in all food quality and temperature treatments. Nevertheless, food quality and temperature modified competitive interactions between the small- and large-bodied Daphnia. In HP and CYANO, both Daphnia species were more strongly suppressed by competitor presence at high than low temperatures, whereas in LP mutual suppression was relatively weaker at higher temperatures. This phenomenon was attributed to higher requirement for P at enhanced temperature which created constraints for population growth thus decreasing competitive interactions at higher temperatures. Mutual competitive suppression in CYANO was weaker than in the HP treatment although cyanobacteria had the greatest negative impact on the abundance of both Daphnia species. In general our results show that the outcome of competition between large and small-bodied cladoceran species was not affected by food quality and/or temperature, yet, these factors markedly altered competitive interactions between species.

Interactions of multiple stressors on the Bombay-duck Harpadon nehereus population in a complex estuarine ecosystem

In an era marked by unprecedented anthropogenic change, marine systems are increasingly subjected to interconnected and dynamic external stressors, which profoundly reshape the behavior and resilience of marine ecological components. Nevertheless, despite widespread recognition of the significance of stressor interactions, there persist notable knowledge deficits in quantifying their interactions and the specific biological consequences that result. To bridge this crucial gap, this research detected and examined the causal relationships between five key exogenous stressors in a complex estuarine ecosystem. Furthermore, a Bayesian Hierarchical Spatio-temporal modeling framework was proposed to quantitatively evaluate the distinct, interactive, and globally sensitive effects of multiple stressors on the population dynamics of a crucial fish species: Harpadon nehereus. The results showed that interactions were detected between fisheries pressure (FP), the Pacific Decadal Oscillation index (PDO), runoff volume (RV), and sediment load (SL), with five of these interactions producing significant synergistic effects on H. nehereus biomass. The SL*PDO and RV*PDO interactions had positive synergistic effects, albeit through differing processes. The former interaction amplified the individual effects of each stressor, while the latter reversed the direction of the original impact. Indeed overall, the synergistic effect of multiple stressors was not favorable, with FP in particular posing the greatest threat to H. nehereus population. This threat was more pronounced at high SL or negative PDO phases. Therefore, local management efforts aimed at addressing multiple stressors and protecting resources should consider the findings. Additionally, although the velocity of climate change (VoCC) failed to produce significant interactions, changes in this stressor had the most sensitive impacts on the response of H. nehereus population. This research strives to enhance the dimensionality, generalizability, and flexibility of the quantification framework for marine multi-stressor interactions, aiming to foster broader research collaboration and jointly tackle the intricate pressures facing marine ecosystems.

Root and biomass allocation traits predict changes in plant species and communities over four decades of global change.

Global change is affecting the distribution and population dynamics of plant species across the planet, leading to trends such as shifts in distribution toward the poles and to higher elevations. Yet, we poorly understand why individual species respond differently to warming and other environmental changes, or how the trait composition of communities responds. Here we ask two questions regarding plant species and community changes over 42 years of global change in a temperate montane forest in Québec, Canada: (1) How did the trait composition, alpha diversity, and beta diversity of understory vascular plant communities change between 1970 and 2010, a period over which the region experienced 1.5°C of warming and changes in nitrogen deposition? (2) Can traits predict shifts in species elevation and abundance over this time period? For 46 understory vascular species, we locally measured six aboveground traits, and for 36 of those (not including shrubs), we also measured five belowground traits. Collectively, they capture leading dimensions of phenotypic variation that are associated with climatic and resource niches. At the community level, the trait composition of high-elevation plots shifted, primarily for two root traits: specific root length decreased and rooting depth increased. The mean trait values of high-elevation plots shifted over time toward values initially associated with low-elevation plots. These changes led to trait homogenization across elevations. The community-level shifts in traits mirrored the taxonomic shifts reported elsewhere for this site. At the species level, two of the three traits predicting changes in species elevation and abundance were belowground traits (low mycorrhizal fraction and shallow rooting). These findings highlight the importance of root traits, which, along with leaf mass fraction, were associated with shifts in distribution and abundance over four decades. Community-level trait changes were largely similar across the elevational and temporal gradients. In contrast, traits typically associated with lower elevations at the community level did not predict differences among species in their shift in abundance or distribution, indicating a decoupling between species- and community-level responses. Overall, changes were consistent with some influence of both climate warming and increased nitrogen availability.

Non-Mendelian transmission of X chromosomes: mechanisms and impact on sex ratios and population dynamics in different breeding systems.

The non-Mendelian transmission of sex chromosomes during gametogenesis carries significant implications, influencing sex ratios and shaping evolutionary dynamics. Here we focus on known mechanisms that drive non-Mendelian inheritance of X chromosomes during spermatogenesis and their impact on population dynamics in species with different breeding systems. In Drosophila and mice, X-linked drivers targeting Y-bearing sperm for elimination or limiting their fitness, tend to confer unfavourable effects, prompting the evolution of suppressors to mitigate their impact. This leads to a complex ongoing evolutionary arms race to maintain an equal balance of males and females. However, in certain insects and nematodes with XX/X0 sex determination, the preferential production of X-bearing sperm through atypical meiosis yields wild-type populations with highly skewed sex ratios, suggesting non-Mendelian transmission of the X may offer selective advantages in these species. Indeed, models suggest X-meiotic drivers could bolster population size and persistence under certain conditions, challenging the conventional view of their detrimental effects. Furthering our understanding of the diverse mechanisms and evolutionary consequences of non-Mendelian transmission of X chromosomes will provide insights into genetic inheritance, sex determination, and population dynamics, with implications for fundamental research and practical applications.

Impacts of Environmental Concentrations of Nanoplastics on Zebrafish Neurobehavior and Reproductive Toxicity.

Nanoplastics, as emerging environmental pollutants, can transport contaminants across marine environments, polluting pristine ecosystems and being ingested by marine organisms. This transfer poses a severe threat to global aquatic ecosystems and potentially impacts human health through the food chain. Neurobehavioral and reproductive toxicity are critical areas of concern because they directly affect the survival, health, and population dynamics of aquatic species, which can have cascading effects on the entire ecosystem. Using zebrafish as a model organism, we investigated the toxic effects of environmental concentrations of polystyrene nanoplastics (PS-NPs). Behavioral assessments, including the novel tank test and open field test, demonstrated significant neurobehavioral changes, indicating increased anxiety and depressive behaviors. A pathological analysis of brain and gonadal tissues, along with evaluations of neurobehavioral and reproductive toxicity biomarkers, revealed that exposure to PS-NPs leads to brain tissue lesions, inflammatory responses, oxidative stress activation, hormone level disruptions, and gonadal damage. Real-time quantitative PCR studies of reproductive gene expression further showed that PS-NPs disrupt the endocrine regulation pathways of the brain-pituitary-gonadal (BPG) axis, causing reproductive toxicity with sex-specific differences. These findings provide crucial insights into the impacts of nanoplastics on aquatic organisms and their ecological risks, offering theoretical support for future environmental protection and pollutant management efforts.

Breeding success of eurasian cranes (<i>grus grus</i>, gruiformes, aves) in the conditions of a changing environment: the impact of climatic and hydrometeorological trends

Theoretical predictions usually assume that changes in conditions caused by climate warming would render negative effects on the population dynamics of many bird species, but evidence is only rarely presented. Changes in phenology, nesting timing, and the physical condition of breeders have been published for a wide range of species in most regions of the Northern Hemisphere; however, data are still insufficient for a better understanding of the consequences for changes in productivity, reproductive success and offspring recruitment. Long-term monitoring (1994–2023) the numbers and age structure of premigratory gatherings of Eurasian cranes in the northern Moscow Region, Central Russia, reveals that, despite the climate warming in the region, the proportion of offspring has not changed over the 30-year long period of observation. The number of young birds is positively related to the temperature of the breeding season; in warmer years, the productivity of Eurasian cranes was higher. In seasons with high precipitation rates, the proportion of chicks was decreased. The reproduction efficiency of cranes on Central Russia is controlled by two parameters: the amount of precipitation and the average temperature during the breeding season.More chicks rise in years with a combination of higher temperatures and low precipitation amounts. Increased precipitations and decreased temperatures lead to reduced proportions of chicks in the premigratory gatherings. The most unfavorable situation for common cranes was low temperatures combined with high precipitations, the proportion of chicks being the minimum in such years.