Search Results (40)

Compared with traditional field techniques, automated and noninvasive bird monitoring techniques, such as passive acoustic monitoring, offer significant advantages. However, the extensive data collected through passive acoustic monitoring can be challenging to analyze and may require the use of machine learning algorithms for efficient processing. BirdNET is a user-friendly and ready-to-use machine learning tool that can recognize more than 6500 wildlife species, including several tropical species. However, the performance of BirdNET in tropical ecosystems has rarely been assessed. Here, we evaluate the effectiveness of BirdNET for monitoring the vocal activity of three Neotropical wetland species from recordings collected over a year in the Brazilian Pantanal: Green Ibis (Mesembrinibis cayennensis), Limpkin (Aramus guarauna), and Sunbittern (Eurypyga helias). BirdNET was able to detect the presence of the three species in 82–92% of the recordings with known presence. Similarly, BirdNET’s ability to correctly identify vocalizations was consistently greater than 77% (range 77–98%), confirming its effectiveness for monitoring these three tropical bird species. The peak vocal activity for the three species occurred during crepuscular periods, at the end of the rainy season, and during the receding season, a period when the risk of nest damage from flood pulses is low and food availability is high owing to the large presence of small water bodies. The use of machine learning algorithms such as BirdNET may improve bird monitoring in tropical areas but also facilitate research that improves our knowledge of birds’ natural history, which remains unknown for many tropical species. Full article

Aleurocanthus spiniferus not only damages plant leaves directly but also causes a sooty blotch due to the honeydew secreted by the nymphs and adults. This pest is widespread and seems to be spreading from low latitude to higher latitude areas where winters are typically colder, indicating an increase in its cold tolerance. Changes in temperature help insects to anticipate the arrival of winter, allowing them to take defensive measures in advance. This study examines the impacts of brief warm pulses on the low-temperature tolerance of A. spiniferus, and analyzes the physiological and biochemical mechanisms underlying its cold adaptation, utilizing seasonal differences in cold tolerance. Intermittent training at 25 °C significantly improved the survival rate of overwintering nymphs (third and fourth instar) at −7 °C. Analysis of seasonal differences in the supercooling point (SCP) and freezing point (FP) revealed that overwintering nymph had the highest cold tolerance in November. Seasonal variation in levels of cold-resistant substances were also observed, with moisture decreasing during overwintering, while fat and glycerol levels increased. Conversely, glucose, sorbitol, and trehalose levels rose significantly at the end of the overwintering period. The expression profile of cold-resistant genes indicated that the aldo-keto reductase family 1 member B1 in Aleurocanthus spiniferus (AspiAKR1B1) shows a significant decrease at the end of the overwintering period. Knocking down AspiAKR1B1 led to a marked reduction in the cold tolerance of A. spiniferus. Therefore, brief warm pulses and AspiAKR1B1 are key factors contributing to the enhanced cold tolerance of A. spiniferus. This research provides theoretical support for preventing the further spread of A. spiniferus to higher latitudes, and offers technical guidance for developing effective pest control measures. Full article

Human decomposition processes generate pulses of nutrients, such as carbon (C) and nitrogen (N) in the form of ammonium and nitrate (NO₃⁻), which are released into the surrounding environment. The little exploration related to the potential of cadaveric leachate to influence the physical chemistry and biology of the soil makes it difficult to obtain data and scientific evidence, and subsequently the predominant objective of the current study was to determine soil contamination through the analysis of parameters of physical chemistry that included organic matter (OM), NO₃⁻, texture, humidity, and pH. Soil samples were taken at different depths in two temporary trials (the dry and rainy seasons) in central Ecuador. The Kruskal–Wallace and ANOVA statistical analyses determined significant differences in relation to the sampling sections and by categories, while there were no significant differences in the inter-season analysis; therefore, the study was based on the data obtained in the dry season. The results indicate a tendency towards contamination in cemeteries categorized as critical, that is, moderate, light, and not suitable due to the high values of OM and humidity measured. On the contrary, the soils that corresponded to the cemeteries classified as suitable yielded low values of the analyzed parameters, which corroborates their capacity for the present and future location of cemeteries. Monitoring and managing soil health is crucial to ensure sustainable environmental practices and protect public health; nonetheless, additional research is suggested to confirm the findings of the current study. Full article

Environmental flow assessment is an essential tool in water resource management. This study employs a holistic approach to evaluate the environmental flow in the Yen Basin, Thanh Hoa, Vietnam. Based on information gathered from a field survey, the Yen River system is divided into five reaches, and environmental objectives and ecological assets are identified in each reach. Hydrological and hydraulic mathematical models are applied to simulate the flow regime in the river, demonstrating their potential to assess environmental flow, especially in basins with limited data. The detailed results from the mathematical model facilitate selecting environmental flow components to address specific objectives for each river reach. By analyzing and selecting the flow regime, this study aims to ensure environmental protection while also considering basin development requirements, laying the groundwork for defining prescribed flow regimes in basin water management. Full article

With a view to creating an inventory of the existing climatic and nutritional condition of the haor (low-lying land) areas along with their cropping systems, this research was carried out in the Dingaputa haor of the Netrakona district of Bangladesh. The main objective was to study the farmers’ concept of climate change issues and their responses in respect to cropping systems and nutrition. This study is crucial for comparing the existing situation and taking future decisions. The feasibility and strategic direction of the present haor agriculture were evaluated using strengths, weaknesses, opportunities, and threats (SWOT) analysis and matrices. The results showed that the farmers’ understanding of climate change was much lower than expected; a maximum of 73.2% farmers pointed out that climate change means frequent flooding, and more than 90% of farmers opined that temperature, early flooding, and lightning have increased over time. They strongly agreed that boro (dry-season-irrigated) rice is affected more frequently by natural hazards than in previous times. Very few farmers (only 14.4%) have taken adaptation strategies, which are less climate-smart and nutrition-sensitive. Only 10.8% of farmers cultivated oilseeds, pulses, and vegetables other than boro rice. A lack of technological knowledge is the main obstacle to practicing climate-resilient, modern cultivation practices. The trends of cultivation and consumption of vegetables by haor farmers are very low, whereas they are agreeable to cultivating nutrition-sensitive and high-value crops if they have technical support. The major strengths of haor agriculture are fertile soil and rice surplus, whereas weaknesses are monocropping and malnutrition. Full article

Describing the acoustic repertoire of cetaceans is necessary to understand the functionality of their sounds and the effect anthropogenic pressures have on animals living in a marine environment. This study provides a description of the acoustic repertoire of bottlenose dolphins (Tursiops truncatus) in the Cres-Lošinj archipelago based on continuous 24-h recordings collected from two monitoring stations, both inside and outside the Natura 2000 Site of Community Importance, during an 8-day period in March/April 2020 and a 13-day period in July/August 2020. A total of 1008 h were visually and aurally analyzed to identify vocalizations and investigate diel and seasonal patterns in their parameters. Furthermore, sound pressure levels were calculated for the low (63 Hz–2 kHz) and high (2 kHz–20 kHz) frequency range. Bottlenose dolphins in the Cres-Lošinj archipelago were found to produce whistles, chirps, low frequency narrow-band sounds, burst pulse sounds, and echolocation clicks showing that dolphins are present at both monitoring stations, during both diel and seasonal periods, in a comparable manner. This paper also provides evidence that whistles, chirps, and low frequency narrow-band sounds change their parameters in relation to the background noise in the area, that varies according to diel and seasonal patterns. This suggests a vocal plasticity in the species and a coping strategy to avoid masking of relevant acoustic signals for the local population in the Cres-Lošinj archipelago. Full article

Chinese bahaba (Bahaba taipingensis) is a critically endangered fish species, which can produce sounds like other Sciaenidae species. In this study, sounds produced by sexually mature Chinese bahaba were recorded during the reproduction season for the first time. Two distinct types of sounds were observed during the reproduction season, termed as single drum and fast drum trains calls. Single drum callings occurred as a series of trains with rapid pulses, while fast drum trains callings were mainly made of a single signal. The single drum and fast drum trains had a peak frequency of 77.8 ± 16.2 Hz and 79.1 ± 8.7 Hz, respectively. Statistical analysis suggested significant differences in −3 dB bandwidth, signal duration, and root-mean-square sound pressure levels, except for peak frequency (p < 0.05) between single drum and fast drum trains sounds. Single drum occurred mainly before dawn (period range from 0:00 to 6:00 am) and less frequently after dusk (18:00–24:00 pm), and the fast drum trains occurred after dawn (6:00 am to 12:00 pm) and dusk (18:00 pm to 24:00 pm). Considering the abundance of Chinese bahaba has significantly declined, passive acoustic monitoring provides a non-invasive and low-cost effective tool to monitor sound production during reproduction season, which may help to facilitate aquaculture management and fishery population conservation in the future. Full article

Modulation of the marine environment in the Natal Bight (~29.1°S, 31.6°E) was studied using daily high-resolution climate reanalysis products and monthly satellite green- and red-band reflectance in the period 2002–2022. The KwaZulu-Natal shelf edge is characterized by a narrow band of upwelling next to the warm Agulhas Current. Strong, reversing longshore winds ~7 m/s and meandering poleward flow ~1 m/s pulse the system, but along the leeward coast that forms the Natal Bight, environmental conditions are buffered by a weak cyclonic gyre. Wind and current shear create a shadow zone that aggregates plankton, recycles nutrients, and sustains marine resources. The seasonal cycle is of high amplitude: the surface heat balance reaches +70 W/m² in December, followed by river discharges ~3 M m³/yr of fresh nutrient-rich water that peak in February. This induces a buoyant surface layer that inhibits wind wave turbulence during summer. By contrast, winter (June–August) cooling −95 W/m² and frequent cyclonic storminess deepen the mixed layer from 25 to 65 m, enabling wind wave turbulence to reach the seafloor (Tugela Bank). Red-band reflectance increases 3-fold from summer to winter and is significantly correlated with net heat balance −0.54, daily wave heights > 2.5 m +0.51, mixed layer depth +0.47, sea surface temp −0.41, and wind vorticity −0.39. Daily longshore winds from the northeast and southwest were, unexpectedly, most amplified in spring (August–October). The seasonality exhibits sequential effects that supports year-round marine nutrification in the Natal Bight. Intra-seasonal fluctuations were related to meandering of the Agulhas Current and changes in longshore winds and shelf waves that impart significant pulsing of near-shore currents at 4–9-day periods. Although the cyclonic gyre in the Natal Bight spins up and down, SST variance was found to be relatively low in its center, where external influences are buffered. Considering linear trends for winds and runoff and surface temperature over the period 1950–2021, we found that northeasterlies increased, runoff decreased, and inshore sea surface temperatures have warmed slowly relative to the adjacent land surface temperature. New insights derive from the use of monthly satellite red-band reflectance and daily 10 km climate reanalysis fields to understand how air–land–sea fluxes modulate the marine environment in the Natal Bight. Full article

Field pea (Pisum sativum L.) is a highly nutritious winter-season pulse crop. It is used as food, feed, and fodder and offers nutritional security to low-income people in developing countries. Different graphical approaches like Principal Component Analysis (PCA) and Genotype + Genotype × Environment (GGE) biplots were used along with the conventional line × tester to identify efficient parents, combining ability effects and distinct heterotic groups in field pea (Pisum sativum L.). The study used a line tester design (9 × 3) for seed yield and its associated traits. In the conventional analysis, lines Aman and HFP 715 and the tester GP02/1108, as well as crosses HFP 715 × GP02/1108, Aman × GP02/1108, and Pant P-243 × HFP 1426 showed the best GCA (General Combining Ability) and SCA (Specific Combining Ability) effects, respectively, for seed yield and its attributes. The ^σ2SCA > ^σ2GCA, and ^σ2D > ^σ2A in almost all the traits indicated control of non-additive gene effects. High manifestations of heterobeltiosis for seed yield were evidenced by the superiority of 24 out of 27 crosses over the better parent. The highest significant heterobeltiosis was observed in the cross HFP 715 × GP02/1108, followed by IPF 14-16 × GP02/1108, IPF 14-16 × HFP 1426, DDR-23 × HFP 1426, DDR-23 × GP02/1108, and Aman × GP02/1108 for yield and its attributes. The biplot techniques were used to analyze data and compare their results with conventional line × tester analysis. Overall, graphical analysis results were very similar to those of traditional analysis. Consequently, it can surely be assumed that these methods could be helpful in presenting data from field pea breeding experiments carried out with line × tester design. Full article

Chickpea (Cicer arietinum L.), the third largest produced pulse worldwide, is primarily grown on marginal soils often characterized by a phosphorus (P)-deficiency that severely hampers yields. The objectives of the study are to investigate the relationships between the P-acquisition, P-use efficiency (PUE) and the agronomical performances towards the developing varieties tolerant to the P-deficiency. We evaluate the impact of the P-deficiency on the growth, yield, germination and nodulation performances of seven chickpea cultivars grown in fields with a low-P soil availability, during two seasons. The adaptive mechanisms to maintain the efficiency of the physiological processes, such as the nitrogen (N)-fixing nodule function, germinability, and possibly photosynthesis, are revealed. In contrast, the large genotypic variation in the yield components, in the P and N acquisition, and in the PUE is observed, supporting the role of the nodules in the P uptake in P-deficient soils. The P-acquisition and utilization efficiencies are genetically decoupled, suggesting designing distinct breeding strategies to promote one or both PUE components. As an outcome, we identify a set of chickpea cultivars adapted to a region with a soil P scarcity, that exhibit efficient N and P metabolism and a superior productivity. This germplasm can be used in breeding programs for low-P input efficient chickpeas. This contributes to the implementation of eco-friendly farming practices while making the most of marginal soils. Full article

Dormancy is a physiological state that confers winter hardiness to and orchestrates phenological phase progression in temperate perennial plants. Weather fluctuations caused by climate change increasingly disturb dormancy onset and release in plants including tree crops, causing aberrant growth, flowering and fruiting. Research in this field suffers from the lack of affordable non-invasive methods for online dormancy monitoring. We propose an automatic framework for low-cost, long-term, scalable dormancy studies in deciduous plants. It is based on continuous sensing of the photosynthetic activity of shoots via pulse-amplitude-modulated chlorophyll fluorescence sensors connected remotely to a data processing system. The resulting high-resolution time series of JIP-test parameters indicative of the responsiveness of the photosynthetic apparatus to environmental stimuli were subjected to frequency-domain analysis. The proposed approach overcomes the variance coming from diurnal changes of insolation and provides hints on the depth of dormancy. Our approach was validated over three seasons in an apple (Malus × domestica Borkh.) orchard by collating the non-invasive estimations with the results of traditional methods (growing of the cuttings obtained from the trees at different phases of dormancy) and the output of chilling requirement models. We discuss the advantages of the proposed monitoring framework such as prompt detection of frost damage along with its potential limitations. Full article

Anchovies are species of ecological and economic importance that inhabit coastal waters, where they are very abundant. The objective of the study was, through high-frequency temporal sampling, to analyze the diversity, seasonal and diel distribution patterns of anchovies and their relationships with environmental variables. For 19 months, 24-h monthly cycles were carried out, taking samples every two hours. Permutational analysis of variance (PERMANOVA) and redundancy analysis (RDA) were used for data analysis. Seven species were captured, of which, Anchoa mitchilli, Anchoa hepsetus, Anchoa lyolepis, Anchoa lamprotaenia and Cetengraulis edentulus are common in brackish waters; however, Anchoviella perfasciata and Engraulis eurystole rarely occur in these systems. For these species, no major threats are known; therefore, they are listed as ‘Least Concern’. A seasonal succession shows pulses during the closed-mouth phase and during the late warm-rainy season. At diel level, A. mitchilli, C. edentulus and A. lamprotaenia showed a markedly nocturnal pattern. RDA correlations showed that salinity, day/night effect, inlet state and rainfall were the most important factors related to anchovy distribution. Segregation along a salinity gradient was observed, in which A. mitchilli was captured mainly at low salinities, while other species occurred mainly at intermediate to high salinities. High-frequency sampling allowed a better understanding of the species richness and abundance patterns of anchovies in the system. Full article

This study investigated hydrological alterations in the sections of the Mura, Drava, and Danube rivers, which together form a unique river landscape proclaimed by UNESCO as the Transboundary Biosphere Reserve Mura, Drava, and Danube (TBR MDD). A coherent network of 12 major protected areas along the rivers highlights their ecological value, which could be endangered by climate change and consequent environmental changes. Statistical analyses, such as the homogeneity test, Mann–Kendall trend test of monthly and seasonal discharges, and empirical probabilities of daily discharges, were applied to discharge data series (1960–2019) from six hydrological stations prior to the calculation of indicators of hydrologic alteration (IHA). This method could be a helpful tool for recognizing the changes in hydrological regimes that can affect river ecosystems. The 33 indicators were organized into five groups. The results showed a decrease in low pulse duration and increase in rise/fall rates and the number of reversals. From an ecological perspective, the results obtained for the probabilities of long flooding periods were particularly significant. They drastically decreased for all three rivers on their stretches within the reserve. According to IHA modeling results, the river sections analyzed were moderately altered with global indicator values between 0.5 and 0.75. The most pronounced hydrological alterations were associated with the frequency and duration of low and high pulses and the rate and frequency of changes in water condition, which could have a significant impact on the ecological values of the TBR MDD. In addition, results show more pronounced climate impact versus human activities. Full article

The growth and physiological effects of either decreased precipitation (e.g., drought) or increased one (e.g., flooding) on trees have been extensively studied. However, less attention has been paid to the questions of whether and how trees respond to changes in precipitation regime with different rainfall amounts. To investigate the effects of water availability on sapling’s growth, tissue levels of non-structural carbohydrates (NSCs), and nutrients, we carried out a greenhouse experiment with Masson pine (Pinus massoniana Lamb.) saplings grown in precipitation amounts of 300, 500, and 700 mm (3 levels) in combination with two levels of a watering regime (i.e., regular watering vs. pulsed watering, i.e., frequent low rainfall coupled with fewer instances of heavy rain) for a growing season in subtropical China. Pulsed watering caused higher soil pH (>7.5) but lower soil organic carbon and soil nutrients, and consequently led to smaller plant biomass and height of the saplings than regular watering, especially in the water amount treatment of 300 and 500 mm. Additionally, higher levels of NSCs in plant tissue concentrations were observed under pulsed watering than under regular watering, due to greater carbon consumption for supporting higher growth rate and a dilution effect by bigger plant size and biomass in the latter. Our results indicated that the growing season precipitation amount of 300 mm is sufficient for the drought-tolerant tree species P. massoniana. In such a case, the growing season precipitation regime rather than the precipitation amount will have a much stronger impact on the tree performance. Full article

The study aimed to conduct advanced semen evaluation tests during routine ram examination periods in the breeding and non-breeding seasons and to investigate their correlation with the dynamics of testicular blood flow. Semen was collected from eighteen rams, and pulse wave Doppler examination before (BBS), during (BS), and after the breeding season (ABS). Routine and advanced semen analysis, including computer-assisted sperm analysis (CASA), sperm chromatin dispersion test (SCD), and motile sperm organelle morphology examination (MSOME), were conducted. In Doppler ultrasonography, the peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI), and pulsatility index (PI) were calculated. In BS period, high sperm concentration (p < 0.0001) and total sperm number/ejaculate (p = 0.008) were noted. During the BBS period, a low percentage of forwarding motility (p = 0.017) and high sperm abnormalities (p = 0.005) were found. Also during this period, both SCD and MSOME revealed high sperm DNA fragmentation (p < 0.0001) and signs of vacuolization (Grade II-IV, p < 0.05). The advanced features of higher sperm abnormalities (Grade IV of MSOME) correlated with an increase RI (ρє <0.60;0.61>) and PI (ρє <0.46;0.52>), whereas the basic percentage of sperm abnormalities correlated with the EDV (ρє <0.44;0.73>) value. One may conclude that the current preliminary study requires further research concerning the monthly examination of a ram to provide full yearly characteristics of the relation between advanced semen evaluation tests and the dynamics of testicular blood flow. Full article