Reliability of environmental DNA surveys to detect pond occupancy by newts at a national scale.
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ABSTRACT:
SUBMITTER: Buxton A
PROVIDER: S-EPMC8789902 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Field studies to detect environmental DNA (eDNA) can be undertaken to infer the presence of a rare or cryptic species in a water body. These studies are implemented by collecting water samples from the water body, processing those samples to isolate genetic material contained in the water sample, and using a laboratory assay to find a species-specific genetic marker within a sample of the genetic material. To date, conventional polymerase chain reaction (PCR) has been one of the most widely used assays in field studies to detect eDNA. This assay is strictly a test for the presence of the genetic marker. It provides no estimate of the concentration of the target genetic marker in the sample or in the environment. Understanding the concentration of a target marker in the environment is a critical first step toward using the results of eDNA field surveys to support inferences about the location and strength of eDNA sources. In this study, the results of eDNA field surveys are combined with a model of the sensitivity of the field survey methods to estimate target marker concentrations using Bayesian updating. The method is demonstrated for Asian carp in the Chicago Area Waterway System (CAWS) using the results of field surveys for eDNA carried out during the period 2009 through 2012, a four-year period during which more than 5,800 two-liter water samples were collected and analyzed using PCR. Concentrations of bighead carp (Hypophthalmichthys nobilis) and silver carp (Hypophthalmichthys molitrix) eDNA are estimated for twenty hydrologic reaches of the CAWS. This study also assesses the sensitivity of these concentration estimates to evidentiary criteria that limit what evidence is used in Bayesian updating based on requirements for sampling intensity and frequency.
| S-EPMC5790220 | biostudies-literature
Project description:ObjectiveAnalysis of environmental DNA (eDNA) is a method that has been used for the detection of various species within water bodies. The great crested newt (Triturus cristatus) has a short eDNA survey season (mid-April to June). Here we investigate whether this season could be extended into other months using the current methodology as stipulated by Natural England.ResultsHere we present data to show that in monthly water samples taken from two ponds (March 2014-February 2015) we were able to detect great crested newt DNA in all months in at least one of the ponds. Similar levels of great crested newt eDNA (i.e. highly positive identification) were detected through the months of March-August, suggesting it may be possible to extend the current survey window. In order to determine how applicable these observations are for ponds throughout the rest of the UK, further work in multiple other ponds over multiple seasons is suggested. Nevertheless, the current work clearly demonstrates, in two ponds, the efficacy and reproducibility of eDNA detection for determining the presence of great crested newts.
| S-EPMC5530555 | biostudies-literature
Project description:The deep seafloor serves as a reservoir of biodiversity in the global ocean, with >80% of invertebrates at abyssal depths still undescribed. These diverse and remote deep-sea communities are critically under-sampled and increasingly threatened by anthropogenic impacts, including future polymetallic nodule mining. Using a multigene environmental DNA (eDNA) metabarcoding approach, we characterized metazoan communities sampled from sediments, polymetallic nodules and seawater in the western Clarion Clipperton Zone (CCZ) to test the hypotheses that deep seamounts (a) are species richness hotspots in the abyss, (b) have structurally distinct communities in comparison to other deep-sea habitats, and (c) that seafloor particulate organic carbon (POC) flux and polymetallic nodule density are positively correlated with metazoan diversity. eDNA metabarcoding was effective at characterizing distinct biotas known to occur in association with different abyssal substrate types (e.g., nodule- and sediment-specific fauna), with distinct community composition and few taxa shared across substrates. Seamount faunas had higher overall taxonomic richness, and different community composition and biogeography than adjacent abyssal plains, with seamount communities displaying less connectivity between regions than comparable assemblages on the abyssal plains. Across an estimated gradient of low to moderate POC flux, we find lowest taxon richness at the lowest POC flux, as well as an effect of nodule size on community composition. Our results suggest that while abyssal seamounts are important reservoirs of metazoan diversity in the CCZ, given limited taxonomic overlap between seamount and plains fauna, conservation of seamount assemblages will be insufficient to protect biodiversity and ecosystem function in regions targeted for mining.
| S-EPMC7754508 | biostudies-literature
Project description:Environmental DNA (eDNA) surveys utilize DNA shed by organisms into their environment in order to detect their presence. This technique has proven effective in many systems for detecting rare or cryptic species that require high survey effort. One potential candidate for eDNA surveying is Kirtland's Snake (Clonophis kirtlandii), a small natricine endemic to the midwestern USA and threatened throughout its range. Due to its cryptic and fossorial lifestyle, it is also a notoriously difficult snake to survey, which has limited efforts to understand its ecology. Our goal was to utilize eDNA surveys for this species to increase detection probability and improve survey efficiency to assist future conservation efforts. We conducted coverboard surveys and habitat analyses to determine the spatial and temporal activity of snakes, and used this information to collect environmental samples in areas of high and low snake activity. In addition, we spiked artificial crayfish burrows with Kirtland's Snake feces to assess the persistence of eDNA under semi-natural conditions. A quantitative PCR (qPCR) assay using a hydrolysis probe was developed to screen the environmental samples for Kirtland's Snake eDNA that excluded closely related and co-occurring species. Our field surveys showed that snakes were found in the spring during the first of two seasons, and in areas with abundant grass, herbaceous vegetation, and shrubs. We found that eDNA declines within a week under field conditions in artificial crayfish burrows. In environmental samples of crayfish burrow water and sediment, soil, and open water, a single detection was found out of 380 samples. While there may be physicochemical and biological explanations for the low detection observed, characteristics of assay performance and sampling methodology may have also increased the potential for false negatives. We explored these outcomes in an effort to refine and advance the successful application of eDNA surveying in snakes and groundwater microhabitats.
| S-EPMC7341209 | biostudies-literature
Project description:The environmental DNA (eDNA) method is the practice of collecting environmental samples and analyzing them for the presence of a genetic marker specific to a target species. Little is known about the sensitivity of the eDNA method. Sensitivity is the probability that the target marker will be detected if it is present in the water body. Methods and tools are needed to assess the sensitivity of sampling protocols, design eDNA surveys, and interpret survey results. In this study, the sensitivity of the eDNA method is modeled as a function of ambient target marker concentration. The model accounts for five steps of sample collection and analysis, including: 1) collection of a filtered water sample from the source; 2) extraction of DNA from the filter and isolation in a purified elution; 3) removal of aliquots from the elution for use in the polymerase chain reaction (PCR) assay; 4) PCR; and 5) genetic sequencing. The model is applicable to any target species. For demonstration purposes, the model is parameterized for bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix) assuming sampling protocols used in the Chicago Area Waterway System (CAWS). Simulation results show that eDNA surveys have a high false negative rate at low concentrations of the genetic marker. This is attributed to processing of water samples and division of the extraction elution in preparation for the PCR assay. Increases in field survey sensitivity can be achieved by increasing sample volume, sample number, and PCR replicates. Increasing sample volume yields the greatest increase in sensitivity. It is recommended that investigators estimate and communicate the sensitivity of eDNA surveys to help facilitate interpretation of eDNA survey results. In the absence of such information, it is difficult to evaluate the results of surveys in which no water samples test positive for the target marker. It is also recommended that invasive species managers articulate concentration-based sensitivity objectives for eDNA surveys. In the absence of such information, it is difficult to design appropriate sampling protocols. The model provides insights into how sampling protocols can be designed or modified to achieve these sensitivity objectives.
| S-EPMC4624909 | biostudies-literature
Project description:BackgroundOver the past few years, the use of molecular techniques to detect cultivation-independent, eukaryotic diversity has proven to be a powerful approach. Based on small-subunit ribosomal RNA (SSU rRNA) gene analyses, these studies have revealed the existence of an unexpected variety of new phylotypes. Some of them represent novel diversity in known eukaryotic groups, mainly stramenopiles and alveolates. Others do not seem to be related to any molecularly described lineage, and have been proposed to represent novel eukaryotic kingdoms. In order to review the evolutionary importance of this novel high-level eukaryotic diversity critically, and to test the potential technical and analytical pitfalls and limitations of eukaryotic environmental DNA surveys (EES), we analysed 484 environmental SSU rRNA gene sequences, including 81 new sequences from sediments of the small river, the Seymaz (Geneva, Switzerland).ResultsBased on a detailed screening of an exhaustive alignment of eukaryotic SSU rRNA gene sequences and the phylogenetic re-analysis of previously published environmental sequences using Bayesian methods, our results suggest that the number of novel higher-level taxa revealed by previously published EES was overestimated. Three main sources of errors are responsible for this situation: (1) the presence of undetected chimeric sequences; (2) the misplacement of several fast-evolving sequences; and (3) the incomplete sampling of described, but yet unsequenced eukaryotes. Additionally, EES give a biased view of the diversity present in a given biotope because of the difficult amplification of SSU rRNA genes in some taxonomic groups.ConclusionsEnvironmental DNA surveys undoubtedly contribute to reveal many novel eukaryotic lineages, but there is no clear evidence for a spectacular increase of the diversity at the kingdom level. After re-analysis of previously published data, we found only five candidate lineages of possible novel high-level eukaryotic taxa, two of which comprise several phylotypes that were found independently in different studies. To ascertain their taxonomic status, however, the organisms themselves have now to be identified.
| S-EPMC428588 | biostudies-literature
Project description:Environmental DNA (eDNA) metabarcoding can greatly enhance our understanding of global biodiversity and our ability to detect rare or cryptic species. However, sampling effort must be considered when interpreting results from these surveys. We explored how sampling effort influenced biodiversity patterns and nonindigenous species (NIS) detection in an eDNA metabarcoding survey of four commercial ports. Overall, we captured sequences from 18 metazoan phyla with minimal differences in taxonomic coverage between 18 S and COI primer sets. While community dissimilarity patterns were consistent across primers and sampling effort, richness patterns were not, suggesting that richness estimates are extremely sensitive to primer choice and sampling effort. The survey detected 64 potential NIS, with COI identifying more known NIS from port checklists but 18 S identifying more operational taxonomic units shared between three or more ports that represent un-recorded potential NIS. Overall, we conclude that eDNA metabarcoding surveys can reveal global similarity patterns among ports across a broad array of taxa and can also detect potential NIS in these key habitats. However, richness estimates and species assignments require caution. Based on results of this study, we make several recommendations for port eDNA sampling design and suggest several areas for future research.
| S-EPMC5995838 | biostudies-other
Project description:BackgroundThe environmental action scale is used to measure the degree of participation in collective environmental actions and has been shown to have adequate psychometric properties in developed countries. However, there are still no studies that have evaluated its performance in the Peruvian population.MethodsIn this instrumental study, the environmental action scale (EAS) was translated, adapted, and validated. The EAS was administered to 352 university students between 18 and 35 years of age (Mage = 23.37, SD = 2.57) from different cities in Peru. A validity analysis was performed using two sources of evidence: content validity and internal structure, carrying out an exploratory factor analysis (EFA) and a confirmatory factor analysis (CFA).ResultsThe structure of the scale has been organized into three oblique factors. The findings confirmed the reliability and validity of the three dimensions of the EAS.ConclusionTherefore, this scale is considered a valid option for assessing environmental action.
| S-EPMC10702606 | biostudies-literature
Project description:BACKGROUND AND PURPOSE: The National Institutes of Health Stroke Scale (NIHSS) is a clinical assessment tool that is widely used in clinical trials and practice to evaluate stroke-related neurological deficits. The aim of this study was to determine the validity and reliability of the Korean version of the NIHSS (K-NIHSS) for evaluating Korean stroke patients. METHODS: The K-NIHSS was translated and adapted with regard to cultural and linguistic peculiarities. To examine its content validity, we quantified the Content Validity Index (CVI), which was rated by 11 stroke experts. The validity of the K-NIHSS was assessed by comparison with the Glasgow Coma Scale (GCS), the modified Rankin Scale (mRS), and the Barthel Index. The reliability of the K-NIHSS was evaluated using the unweighted kappa statistics for multiple raters and an intraclass correlation coefficient (ICC). RESULTS: The CVI of the K-NIHSS reached 0.91-1.00. The median K-NIHSS score at baseline was 3 (interquartile range, 2-7), and the mean±SD score was 6.0±6.6. The baseline K-NIHSS had a significantly negative correlation with the GCS at baseline and the Barthel Index after 90 days. The K-NIHSS also had a significantly positive correlation with the mRS after 90 days. Facial paresis and dysarthria had moderate interrater reliability (unweighted kappa, 0.41-0.60); kappa values were substantial to excellent (unweighted kappa, >0.60) for all the other items. The ICC for the overall K-NIHSS score was 0.998. The intrarater reliability was acceptable, with a median kappa range of 0.524-1.000. CONCLUSIONS: The K-NIHSS is a valid and reliable tool for assessing neurological deficits in Korean acute stroke patients.
| S-EPMC3469797 | biostudies-other
Project description:While the number of published marine studies using environmental DNA (eDNA) has increased substantially in recent years, marine fish surveys are still scarce. To examine the potential for eDNA to support marine fisheries monitoring surveys, we optimized an eDNA isolation method, developed a multispecies assay and tested it on eDNA samples collected along the Pacific coast of the United States. Four commercial DNA extraction kits that exploit the capability of the nucleic acids binding a solid phase (two using a silica matrix and two magnetic beads) as well an organic separation method were tested. A species-specific multiplex qPCR assay was developed and tested to simultaneously target Pacific hake (Merluccius productus), Pacific lamprey (Entosphenus tridentatus) and eulachon (Thaleichthys pacificus). The specificity of the assay was tested in silico, in vitro and in natura. Environmental DNA isolation using phenol:chloroform:isoamyl purification with a phase lock was optimized and yielded the highest amount of total and target DNA and was used to extract 46 marine water samples for the detection of the three species of interest. The multiplex qPCR assay used in the quantification process was also optimized to provide convenience and accuracy. Pacific hake was present in 44% of the eDNA samples while the other two species were absent. Here, we present a complete workflow for the simultaneous detection and quantification of multiple marine fish species using eDNA. This workflow supports large-scale at-sea sampling efforts with preservation at ambient temperatures and has demonstrated DNA extraction efficiency and reliability. The multiplex qPCR assay is shown to be sensitive and specific for the purposes of simultaneously monitoring the relative abundance of multiple targeted fish species.
| S-EPMC8476043 | biostudies-literature