Ecological Studies Research Articles

Ecological traits of the Patagonian blenny, Eleginops maclovinus (pisces, eleginopidae), in the río Gallegos estuary (southwestern Atlantic)

Eleginops maclovinus is an important resource for artisanal fisheries in South America (ca. 20-200 tons per year) Therefore, biological and ecological studies are necessary for the conservation of this species for fishing purposes. In this context, the accompanying fish fauna of E. maclovinus, their monthly and tidal abundance (both daytime and night), and their feeding behaviour were analysed. The study was conducted in the intertidal of Río Gallegos estuary (Argentina) using a gill net, from December 2020 to May 2021. A total of 788 fish individuals were counted, corresponding to 9 spp. E. maclovinus were the most abundant (ca. 81 % of total specimens), registering a mean value of 4-7 individuals per day from December to April, and the lowest in May (1 individual per day). The comparison of tidal regimes established that E. maclovinus recorded higher abundances during night (4 individuals per day) than daytime tides (2 individuals per day). Feeding analysis showed a total of 11 food items, being the bivalve Darina solenoides the most frequent prey. This study suggests that E. maclovinus is the dominant species in the intertidal zone, feeding on most abundant and available benthic organisms. The present work provides important information for the implementation of sustainable artisanal fisheries in the area.

Overview and Comparison of Deep Neural Networks for Wildlife Recognition Using Infrared Images

There are multiple uses for single-channel images, such as infrared imagery, depth maps, and others. To automatically classify objects in such images, an algorithm suited for single-channel image processing is required. This study explores the application of deep learning techniques for the recognition of wild animals using infrared images. Traditional methods of wildlife monitoring often rely on visible light imaging, which can be hindered by various environmental factors such as darkness, fog, and dense foliage. In contrast, infrared imaging captures the thermal signatures of animals, providing a robust alternative for wildlife detection and identification. We test a Convolutional Neural Network (CNN) model specifically designed to analyze infrared images, leveraging the unique thermal patterns emitted by different animal species. The model is trained and tested on a diverse dataset of infrared images, demonstrating high accuracy in distinguishing between multiple species. In this paper, we also present a comparison of several well-known artificial neural networks on this data. To ensure accurate testing, we introduce a new dataset containing infrared photos of Slovak wildlife, specifically including classes such as bear, deer, boar, and fox. To complement this dataset, the Fashion MNIST dataset was also used. Our results indicate that deep learning approaches significantly enhance the capability of infrared imaging for wildlife monitoring, offering a reliable and efficient tool for conservation efforts and ecological studies.

Inequalities in local government expenditure on environmental and regulatory services in England from 2009 to 2020: a longitudinal ecological study

BackgroundGastrointestinal (GI) infections affect one in five people in the UK and local authorities play a crucial role in controlling these infections. However, there have been substantial reductions in funding...

Role of turnover, downsizing, overtime and night shifts on workplace violence against healthcare workers: a seven-year ecological study

BackgroundAbout one-third of workers identify organisational factors as contributors to workplace violence (WPV), but the associations between these factors and WPV have primarily been explored retrospectively and with measures of perceived organisational constraints, hence providing limited information for prevention. Therefore, we assessed whether objectively measured ward-level indicators of turnover, downsizing, overtime, and night shifts are associated with the occurrence of WPV and whether these associations vary by ward type.MethodsWe conducted an ecological study at a university hospital in northern Italy from 2016 to 2022, using wards as statistical unit (average: 230 wards per year). Active surveillance of WPV was based on an in-hospital incident reporting procedure, updated in November 2021 based on Health Regional Administration guidelines; 2021 was therefore excluded as a transition year. Individual-level administrative data were used to compute ward-level yearly indicators of turnover, downsizing, overtime and night shifts per active worker. Using generalised linear models, we estimated rate ratios (RRs) for yearly WPV counts per 1 SD increase in the indicators, controlling for study period, ward type (emergency department [ED], psychiatric ward, other) and ward sociodemographic composition.ResultsA total of 337 WPV episodes occurred in the 1381 ward-year observations. The WPV rates per 100 active workers per year increased from 1.40 (95%CI: 1.23–1.60) during 2016–2020 to 3.48 (2.90–4.17) in 2022. Higher turnover (RR, 95%CI: 1.47, 1.23–1.75) and downsizing (1.12, 1.00-1.24) were associated with a greater occurrence of WPV across all wards; these associations were consistent across the study periods. In wards with night shift scheduling, turnover (1.64, 1.40–1.92), downsizing (1.21, 1.04–1.40) and the mean number of night shifts (2.50, 1.37–4.56) were associated with WPV. The association between night shifts and WPV was greater in psychiatric wards (RR = 8.73; interaction p-value = 0.02), whereas the role of downsizing was greater in EDs (RR = 1.42, interaction p-value = 0.09) and the role of turnover was greater in the other wards (RR = 1.34, interaction p-value = 0.16).ConclusionWork organisational factors are associated with the occurrence of WPV episodes against healthcare workers. Ward type-tailored priorities should be given to minimising turnover and downsizing and promoting a fairer allocation of night shifts to decrease WPV occurrence.

BASS - Biodiversity Assessments at Small Scales

Much of the work developed on biodiversity dynamics due to climate change focuses on large scales. Yet, we know that small scale is critical to fully understand biodiversity change, particularly for plants and small or less mobile organisms which might seek refuge in sites that keep specific microclimatic and biotic conditions dampening the effects of large-scale changes. The project BASS - Biodiversity Assessment at Small Scales - aims to explore the intricate relationships between small-scale environmental variations in space and time and biodiversity patterns. Central to our study is researching how microclimatic conditions, such as potential solar radiation, influence species occurrence, abundance, community composition and biotic interactions within a Mediterranean context. Our objectives include gaining a deeper understanding of the effects of localised environmental conditions and their change in time on biodiversity, providing critical data for an under-researched Mediterranean Biodiversity Hotspot region, and examining the dynamics of small-sized species, particularly plants and invertebrates. We have established a network of 16 fixed sampling points across the Lisbon University field station - Herdade da Ribeira Abaixo (HRA), Grândola (South Portugal): eight with high and eight with low potential solar radiation. Each of these plots will serve as a 'mesocosm' for detailed ecological studies in the next decades. This framework will support a variety of research projects each focusing on different taxa and questions, including Masters' theses, PhD dissertations and independent studies, thereby fostering a collaborative research environment. By integrating previously collected data during the last three decades with new findings, we aim to offer valuable insights into the processes underlying ecosystem functioning and change at small spatial scales. This project not only addresses fundamental ecological questions, but also contributes to sustainable landscape management and biodiversity conservation efforts.

New insights on the evolution of processionary moths (Thaumetopoea spp., Lepidoptera, Notodontidae) based on a RAD‐seq phylogeny

AbstractThaumetopoea is a genus of Lepidoptera referred to as the processionary moths species, that comprises famous defoliators of forest trees. They are also a threat to human and animal health due to the urticating setae carried by their larvae. Their phylogenetic relationships were studied so far using morphological data, mitochondrial DNA and only a few nuclear markers. Results remained controversial so far, notably for the winter Conifer‐feeding species complex encompassing T. pityocampa and T. wilkinsoni. In particular, since the first identification of divergent mitochondrial clades, several new species were described and incongruent phylogenies were proposed in this group. We here explored the potential of nuclear RAD‐seq data to resolve these inconsistencies and compare the resultant phylogeny with the information provided by the mitochondrial COI gene. It allows to propose a robust phylogeny and decipher cases of mitochondrial introgressions and nuclear‐mitochondrial discordance, which raises doubts about the validity of some recently described species. Hence, we recommend caution before describing new taxa in this group from mitochondrial data alone. Species delineation between geographically bounded and genetically differentiated lineages cannot be addressed pertinently without dedicated sampling and associated population genomic and ecological studies.

Navigated range expansion promotes migratory culling

Motile organisms can expand into new territories and increase their fitness, while nonmotile viruses usually depend on host migration to spread across long distances. In general, faster host motility facilitates virus transmission. However, recent ecological studies have also shown that animal host migration can reduce viral prevalence by removing infected individuals from the migratory group. Here, we use a bacteria-bacteriophage copropagation system to investigate how host motility affects viral spread during range expansion. We find that phage spread during chemotaxis-driven navigated range expansion decreases as bacterial migration speed increases. Theoretical and experimental analyses show that the navigated migration leads to a spatial sorting of infected and uninfected hosts in the copropagating front of bacteria-bacteriophage, with implications for the number of cells left behind. The preferential loss of infected cells in the copropagating front inhibits viral spread. Further increase in host migration speed leads to a phase transition that eliminates the phage completely. These results illustrate that navigated range expansion of the host can promote the migratory culling of infectious diseases in the migration group.

A Simple Method for Triple Stable Isotope Analysis of Cellulose, Sugar, and Bulk Organic Matter-Advances and Limitations.

Determining several isotope ratios in one analysis multiplies the information that can be retrieved from a sample in a cost-efficient way. The stable isotope ratios of hydrogen (δ2H), carbon (δ13C), and oxygen (δ18O) in organic compounds are highly relevant due to their complimentary hydroclimatic and physiological signals. Different types of organic material reflect different processes and integration times, like short term in leaf sugars and long term in tree ring cellulose, but currently, no simple method exists for their triple isotope analysis. Here, we present a method that enables the isotopic analyses of the three elements H, C, and O in one run and is applicable to different types of carbohydrates and bulk organic matter. We discuss all steps required from water vapor equilibration necessary for obtaining reliable δ2H values of carbon-bound H to high-temperature conversion (HTC) of the sample to CO and H2 and to the mass-spectrometric isotope-ratio analysis. We show that reliable triple isotope analysis is possible for a large range of samples, although it results in some reduction of precision compared to individual isotope analysis. Important considerations are the equilibration procedure, the type of autosampler, selection of HTC reactor, the influence of nitrogen in the sample, the verification of δ13C values obtained by HTC versus combustion, and the selection of reference materials. By presenting a relatively simple triple-isotope method, we promote the use of multi-isotope studies in environmental sciences, which helps in addressing many important climate and ecological research challenges that we face today.

The advertisement call of Leptobrachella dushanensis (Anura, Megophryidae)

We describe the advertisement call of the Dushan Leaf Litter Toad, Leptobrachella dushanensis, based on recordings obtained from three individuals from its type locality. The advertisement call of L. dushanensis consists of a single note with a dominant frequency of 4.84–4.91 kHz. Furthermore, we compare the differences in advertisement calls between L. dushanensis and its sister species, Leptobrachella dong. The advertisement calls of L. dushanensis and L. dong can be clearly distinguished. Our findings provide bioacoustic evidence supporting the taxonomic status of L. dushanensis and provide basic data for future behavioral and ecological studies on Leptobrachella.

Oral vancomycin use and incidence of vancomycin-resistant enterococci: time-series analysis

SummaryBackgroundVancomycin exposure is a major risk factor for vancomycin-resistant enterococci (VRE) colonisation, but the relationship between oral vancomycin and the risk of VRE colonisation remains poorly understood without ecological evidence. In this study, we investigated the association between oral vancomycin usage and the incidence of hospital-acquired VRE using a time-series analysis.MethodsThis retrospective ecological study analysed monthly data on antibiotic usage and VRE incidence from January 2013 to December 2022 at a 2700-bed hospital in South Korea. Antibiotic usage was measured in days of therapy (DOT) per 1000 patient-days. Hospital-acquired VRE incidence was defined as the number of VRE isolates identified more than 48 h after admission per 1000 patient-days. The association between oral vancomycin use and VRE incidence was assessed using a multivariate autoregressive integrated moving average (ARIMA) regression model incorporating lag structures.ResultsOver 10 years, 5,763 clinical VRE isolates were identified, with 5,133 (89%) being hospital-acquired. Oral vancomycin usage and VRE incidence showed significant upward trends during the study period. In the final ARIMA model adjusting for various types of antibiotic use and baseline VRE carriage rate, a significant association was observed between oral vancomycin use and VRE incidence (coefficient: 0.0160, 95% CI: 0.0030 to 0.0290, P = 0.0162), with an R-squared value of 0.76. Sensitivity analyses demonstrated the robustness of the association between oral vancomycin use and VRE acquisition across various time lags between antibiotic use and VRE incidence.ConclusionsThere was a significant association between institutional oral vancomycin use and hospital-acquired VRE incidence, highlighting the need for antibiotic stewardship for oral vancomycin use to contain the nosocomial spread of VRE in addition to infection control measures.

Sociodemographic inequalities in residential nighttime light pollution in urban Bulgaria: An environmental justice analysis

IntroductionOutdoor nighttime light (NTL) is a potential anthropogenic stressor in urban settings. While ecological studies have identified outdoor NTL exposure disparities, uncertainties remain about disparities in individual exposure levels, particularly in Europe. AimTo assess whether some populations are disproportionately affected by outdoor NTL at their residences in urban Bulgaria. MethodsWe analyzed 2023 data from a representative cross-sectional survey of 4,270 adults from the five largest Bulgarian cities. Respondents’ annual exposures to outdoor artificial nighttime luminance were measured using satellite imagery and assigned at their places of residence. We calculated the Gini coefficient as a descriptive NTL inequality measure. Associations between respondents’ NTL exposure levels and sociodemographic characteristics were assessed by estimating quantile mixed regression models. Stratified regressions were fitted by gender and for each city. ResultsWe found moderate distributive NTL inequalities, as indicated by a 0.214 Gini coefficient. Regression analyses found associations between greater NTL exposure and higher educational attainment. Respondents with incomes perceived as moderate experienced less NTL exposure at the 0.5 and 0.8 quantiles, while unemployed respondents experienced lower exposure at the 0.2 and 0.5 quantiles. We observed null associations for the elderly and non-Bulgarian ethnicities. Regardless of the quantile, greater population density was associated with higher NTL levels. Stratification by sex did not yield substantial differences in the associations. We observed notable city-specific heterogeneities in the associations, with differences in the magnitudes and directions of the associations and the NTL quantiles. ConclusionsNTL exposures appeared to embody an environmental injustice dimension in Bulgaria. Our findings suggest that some sociodemographic populations experience higher exposure levels to NTL; however, those are not necessarily the underprivileged or marginalized. Identifying populations with high exposure levels is critical to influencing lighting policies to ease related health implications.

Challenges and opportunities when studying movement ecology in science and practical conservation

Movement is a key mechanism influencing biodiversity patterns and ecosystem processes. Movement ecology science aims to understand the causal relationships between environmental conditions, animal movements, interactions and coexistence of species, as well as effects of movement patterns on ecosystem processes. In contrast, practical conservation primarily aims to understand organisms' movements to improve species management, protection, legal monitoring or risk assessment, and species-habitat interactions. Despite the many studies of movement ecology in basic and applied sciences as well as in practical conservation in terrestrial ecosystems, knowledge gain and transfer between disciplines are limited. Better integration and linking of both disciplines would result in diverse science-practice synergies, but these are currently constrained by numerous challenges that need to be overcome. From a scientific perspective, knowledge gain from practice is limited by multitude of case studies with limited spatial and temporal resolution. This can be overcome by improving access and combining the diversity of data for a research area that often deals with small sample sizes. From a practical perspective, the movement ecology framework which is often dedicated to basic research, and access and language barriers of scientific publications limit the application of scientific results in practice. Here movement ecologists should be encouraged to consider conservation issues more frequently in addition to basic research. The transfer of scientific results could be improved by scientists providing sufficient details for practitioners to extract relevant information and publish at least an open-access abstract in local language with clear management recommendations. Further, the use of open-access repositories allows both, scientists and practitioners an overview of the multitude of studies and helps to share data in order to derive general conclusions. Challenges impacting science and practice can be conceptual, organisational and technical in nature. Such constrains can be overcome, for example, by providing verified trapping protocols, using recent technological developments and analytical methods combined with trainings on these state-of-the-art tracking and analysing tools. In particular, collaborative project planning between scientists and practitioners can help to improve the sampling design of applied studies and broaden the data base for science in order to significantly advance the movement ecology framework and gain comprehensive knowledge for practical conservation.

Environmental Pollution and the Risk of Congenital Hypothyroidism: Insights from a French Nationwide Retrospective Ecological Cohort Study

ObjectiveTo assess the potential association between congenital hypothyroidism (CH) and third-trimester maternal exposure to nitrate and perchlorate in tap water and to particulate matter (PM) in outdoor air. MethodsUsing the French National Health Data System (SNDS), a retrospective ecological cohort was created, including all children born in France between 2014 and 2019. Ecological data for each child's municipality were used to examine associations, measured as odds ratios (OR), between mean exposure levels and CH in 1,417,402 newborns . Both single and multipollutant analyses were undertaken. To limit residual bias from the administrative nature of SNDS, analyses were conducted at both national and regional levels. The Benjamini-Hochberg approach was used to account for multiple testing. ResultsHigher exposure to nitrates was associated with a greater risk of permanent CH (OR [95%CI] = 1.017 [1.001;1.035] in the Nord-Pas-de-Calais region and 1.024 [1.001;1.048] for the Pays-de-la-Loire region). Higher exposure to PM2.5 or PM10 was associated with a lower risk of permanent CH (OR [95%CI] = 0.928 [0.873;0.982] for PM10 in the Nord-Pas-de-Calais). These findings were confirmed in multi-pollutant analyses. ConclusionsIn some French regions, prenatal exposure to nitrate ions in tap water was significantly associated with an elevated risk of permanent HC, while exposure to PM was significantly associated with a decreased risk. However, using municipal-level exposure proxies may introduce ecological bias, and results were not robust enough to draw firm conclusions about pollutant influence on CH risk.

Associations between Momentary Mental States and Concurrent Social Functioning after Remission from First Episode Psychosis: A HAMLETT Ecological Momentary Assessment Study

Associations between Momentary Mental States and Concurrent Social Functioning after Remission from First Episode Psychosis: A HAMLETT Ecological Momentary Assessment Study

Female homicides in Brazil: global burden of disease study, 2000–2018

Female homicides are a public health-relevant issue, and its spatial distribution may evidence socioeconomic vulnerabilities. This study aims to analyze the temporal and spatial trends of female homicides in Brazil and investigate socioeconomic-demographic factors associated with it. This is an ecological, descriptive, and analytical epidemiological study investigating the age-standardized female homicide rate in all Brazilian municipalities between 2000 and 2018, divided into three periods. Spatial and temporal analyses were conducted using the Global Moran's Index and LISA to identify clusters of high and low rates. Rates were also calculated by population size and means of violence across macro-regions. For the last period, a multivariable linear regression model analyzed the association of female homicide rates with social, economic, and geographic factors. Female homicide rates in Brazil remained high during the studied period, with differences in trends between regions. Among the potentially associated factors, it was observed that male homicide rate, the high percentage of violent deaths among black women and those with low levels of education, in addition to the low Gross Domestic Product (GDP) per capita, were positively associated with female homicide, whereas larger cities were negatively associated. These findings show that Brazil is a country with a high risk of female homicide. Nevertheless, the vulnerability of women is unequally distributed in the country. Female homicides are mostly caused by domestic conflicts but can also be influenced by changes in the urban and social contexts. This project is funded by the Bill & Melinda Gates Foundation.

Daily fluctuations in adolescents' sleep predict next-day attention, sleepiness, and fatigue: an ecological momentary assessment study over 28 days.

Current understanding of the associations between adolescents' daily sleep and daytime alertness and fatigue under naturalistically occurring restricted (school) and unrestricted (vacation) sleep opportunities is limited. A convenience sample of adolescents (n = 205; 54.1% females, Mage ± SD = 16.9 ± 0.87 years) completed daily measures of sleep, alertness, and fatigue over 28 days (2 weeks during school, and the subsequent 2-week vacation). Actigraphy and sleep diary total sleep time (TST) and sleep efficiency (SE) were measured. Participants self-reported sleepiness and fatigue every morning and afternoon, and completed a tablet-based, 3.2-min psychomotor vigilance task (PVT) every afternoon. Cross-lagged multilevel models tested daily TST and SE as predictors of next-day subjective sleepiness/fatigue and PVT performance. Between- (i.e., differences between individuals) and within-person associations (i.e., whether nights with higher-than-individual's-average TST/SE, predict next-day outcomes) were tested simultaneously. Covariates included previous-day outcome, day of the week, study day (1-28), school/vacation, chronotype, and sociodemographic variables. Within-persons, higher-than-average TST and SE (both actigraphy and diary) predicted better next-day PVT performance (all p ≤ .006), and lower subjective sleepiness and fatigue the following morning and afternoon (all p ≤ .032). Between-persons, adolescents with higher overall diary SE had lower morning subjective sleepiness (p < .001) and fewer PVT false starts in the afternoon (p = 0.02). Nights with longer- and higher-than-average sleep efficiency (both actigraphy and diary) predicted better daytime alertness and fatigue, both when examined objectively via sustained attention and via self-report. These findings are relevant for understanding the significance of sleep for adolescents' day-to-day alertness levels and fatigue, particularly in the context of classroom learning and road safety.

Effects of Systematically Guided vs. Self-Directed Laparoscopic Box Training on Learning Performances: An Observational Study.

Minimally invasive surgery is increasing in all fields of surgery. It is currently unknown whether structured training is superior to self-directed training. The aim of this study is to analyze the enhancement of surgical skills in laparoscopy box trainers in a systematically guided training program compared to self-directed training. Two groups of 40 medical students were included in the study between 04/2021 and 01/2023. Each training session on the laparoscopic box trainer (Medishield BV, NL) was automatically protocolled, including time, force, and path length. The structured group consisted of 21 students working in peer tandem, while the self-directed group consisted of 19 last-year students in their four-month elective. The observational study was conducted in an ecological study design. The self-directed cohort completed an average of 15 training sessions compared to the structured cohort's 10 sessions. All participants in both groups improved in time, path length, and force. The structured cohort showed nearly linear improvement, while the self-directed cohort had high deviation in results. Supervision and collaborative work positively influence laparoscopic training success. Mere availability of training does not exploit the potential of laparoscopic box trainers. Curriculums for young surgeons or medical students should include institutionalized training with a structured schedule and a training partner for improved outcomes.

Modification of the association between cold spells and cardiovascular disease by changes in natural gas prices: A nationwide time-series study

BackgroundAlthough the association between low ambient temperature and cardiovascular disease (CVD) is well-established, the effect of winter energy prices on this association remains unknown. AimThis ecological study aimed to investigate whether changes in natural gas prices (NGP), which account for a significant portion of winter energy prices in Korea, affect the association of cold spells with hospital admissions and mortality due to CVD. MethodsData from the National Health Insurance Service and Statistics Korea were used to determine the daily number of hospital admissions and mortality rates associated with CVD. From January 2012 to February 2017, the NGP continually increased by 24.1%. From January 2012 to December 2014 the NGP continually decreased by 32.6% owing to the Korea Gas Corporation’s management decisions, independent of external socioeconomic factors. We investigated the differences in the associations between cold spells and CVD-related outcomes in price-increasing and price-decreasing periods using a Poisson regression with a distributed lag nonlinear model. Cold spells were assessed on two consecutive days at the 5th percentile of the temperature for each region. ResultsThe meteorological factors and air pollution levels were similar between the two periods. The association between cold spells and hospital admissions due to CVD was stronger during the price-increasing period than during the price-decreasing period [ratio of cumulative relative risk (RRR) = 1.71, 95% confidence interval (CI): 1.31–2.22]. The difference in the association with mortality due to CVD between the two periods was not significant, although the point estimate remained >1 (RRR = 1.11, 95% CI: 0.90–1.38). ConclusionsChanges in energy prices may modify the cold spell-related CVD risk, possibly by inducing behavioral changes to manage energy expenditure. Policymakers should take into account the potential public health implications of changes in energy prices, alongside their economic effects.

Integrating complexity in population modelling: From matrix to dynamic models

Matrix models are widely used in population ecology studies and are valuable for analysing population dynamics, although they are limited in the use of time-varying parameters. This limitation can be overcome by dynamic models. In this study, we revisit a previously published study on a matrix model of a population of the box jellyfish Carybdea marsupialis (L. 1758) in the Western Mediterranean. A dynamic model integrating the transition matrix of the original model is developed in STELLA Architect with the following improvements: (1) Sensitivity study of the reliability of the methodology for calculating the transition matrix and estimation of the errors of the fitting parameters; (2) Closure of the jellyfish life cycle by adding the polyp stage. This will make it possible to simulate scenarios of ecological interest over several years such as a decline in food supply, jellyfish removal strategies, changes in drift currents and changes in substrate availability for planulae to settle. (3) The inclusion of more biological reality. In particular, a temporal pattern of strobilation is added, which improves the fit of the model to the field data.

A Simple and Cost-Effective Extraction for Piscine Environmental DNA Metabarcoding Using Guanidine Hydrochloride Method.

Environmental DNA (eDNA) metabarcoding is a valuable tool for assessing aquatic biodiversity, but the high cost and complexity of DNA extraction pose challenges for widespread adoption, especially in developing countries. This study presents a cost-effective eDNA extraction method using a guanidine hydrochloride (GuHCl) buffer, proteinase-K digestion, and isopropanol precipitation to improve the detection of fish communities. Comparison with the Qiagen DNeasy Blood & Tissue Kit using MiFish universal primers showed that the GuHCl protocol detected more fish species in freshwater samples, with comparable performance in relative read abundance metrics. However, the GuHCl method exhibited higher PCR inhibition in brackish samples, likely due to salinity and natural inhibitors. The results suggest that the GuHCl-based method is a viable alternative, offering enhanced sensitivity for low-abundance species in freshwater samples and cost savings. This protocol facilitates large-scale eDNA metabarcoding for ecological studies and conservation management efforts.•The GuHCl protocol identified a greater diversity of fish species in freshwater samples than the Qiagen kit, but detected fewer species in brackish water samples.•Both extraction methods demonstrated robust positive correlations in metrics of relative read abundance.