Field Samples Research Articles

An automated sample generation method by integrating phenology domain optical-SAR features in rice cropping pattern mapping

Accurate spatio-temporal information on rice cropping patterns is vital for predicting grain production, managing water resource and assessing greenhouse gas emissions. However, current automated mapping of rice cropping patterns at regional scale is heavily constrained by insufficient training samples and frequent cloudy weathers in major rice-producing areas. To tackle this challenge, we proposed a Phenology domain Optical-SAR feature inTegration method to Automatically generate single (SC-Rice) and double cropping Rice (DC-Rice) sample (POSTAR) for efficient and refined rice mapping. POSTAR includes three major steps: (1) generating a potential rice map using a phenology- and object-based classification method with optical data (Sentinel-2 MSI) to select candidate rice samples; (2) employing K-means to identify SC- and DC-Rice candidate samples according to unique SAR-based (Sentinel-1 SAR) phenological features; (3) implementing a two-step refinement strategy to filter high-confidence SC- and DC-Rice samples, maintaining a balance between intraclass phenological variance and sample purity. Test areas selected for validation include the Dongting Lake plain and Poyang Lake plain in South China, as well as Fujin county located in the Sanjiang plain of North China. POSTAR proved effective in producing reliable SC- and DC-Rice samples, achieving a high spectral correlation similarity (>0.85) and low dynamic time wrapping distance (<8.5) with field samples. Applying POSTAR-derived samples to random forest classifier yielded an overall accuracy of 89.6%, with F1 score of 0.899 for SC-Rice and 0.938 for DC-Rice in the Dongting Lake plain. Owing to the incorporation of knowledge-based optical and SAR phenological features, POSTAR exhibited strong spatial transferability, achieving an overall accuracy of 96.0% in the Poyang Lake plain and 97.8% in the Fujin county. These results demonstrated the effectiveness of the POSTAR method in accurately mapping rice cropping patterns without extensive field visits, providing valuable insights for crop monitoring in large, diverse, and cloudy regions through the integration of optical and SAR data.

Precision Remediation of Mining Soils through On-Site Investigation and Large-Scale Synthesized Ferrosilicate

To seek a restoration plan for the safe use of agricultural land around mining areas, this study focuses on the regions around a mining plant in Huidong County, western Sichuan Province, affected by lead–zinc mining, and the precise remediation of heavy metal pollution through large-scale synthesis of iron silicate. In this study, we investigated heavy metal pollution in the vicinity of the mining area and proposed a treatment strategy using large-scale synthesis of iron silicate to mitigate this pollution. According to field investigation and sampling analysis, the collected soil samples contained excessive Cd, Pb, and Zn. Cd is a heavy metal related to lead–zinc mining. The planting of crops such as loquats and garlic with a high accumulation coefficient for Cd was found inappropriate for the research area. Instead, it was recommended to plant economically important crops like mangoes and peaches which had lower heavy metal accumulation. On the basis of field investigation, the study area was seriously polluted by heavy metals, among which Cd was 4.0 times higher than the standard of agricultural land. In order to accurately passivate excessive Cd, Zn, and Pb, iron silicate material was put into mass production. In situ passivation experiments showed that when the soil water content was between 25% and 20%, adding 4% silicate material could rapidly reduce the content of effective heavy metals in the soil and the heavy metal content of garlic and other cash crops in the research area by about 8%. After conducting a field investigation, it has been determined that the large-scale preparation of iron silicate can accurately repair soil contaminated by heavy metals in the vicinity of mining areas. In conclusion, iron silicate is capable of effectively reducing the pollution of heavy metals on agricultural land and facilitating the safe utilization of such land.

Leaf-cutting ants’ distribution in an elevation gradient in central Argentina

ABSTRACT Leaf-cutting ants are among the most prominent herbivores in neotropical forests and savannas, and Argentina represents the southern limit of their distribution. Despite their importance, few systematic studies analyze the presence and distribution of leaf-cutting ants in Argentina. Our aim was to describe, through an intensive field sampling, the leaf-cutting ant species present in the central Argentine mountains and analyze their distribution along the elevation gradient. We collected ants from 69 nests in 56 out of the 250 plots visited along the study elevation gradient (400–2700 m above sea level) in seven different habitats, from forests to rocky areas. We found six species. The most frequent were Acromyrmex lobicornis and Acromyrmex crassispinus, while Acromyrmex heyeri, Amoimyrmex silvestrii, Amoimyrmex striatus, and Amoimyrmex bruchi were far less frequent. The species distributed at the highest elevation was A. lobicornis (1223 to 2163 m a.s.l.), showing significant differences with the other species. We found leaf-cutting ants in all habitats, with a higher presence in grazing lawns, shrublands, and exotic forests. Our results indicate that leaf-cutting ants are present in most of the mountain range, as the area above their upper limit of distribution represents less than 5% of the total mountain area.

Altered Functional Responses of the Retina in B6 Albino Tyrc/c Mice.

Mammals with albinism present low visual discrimination ability and different proportions of certain retinal cell subtypes. As the spatial resolution of the retina depends on the visual field sampling by retinal ganglion cells (RGCs) based on the convergence of upstream cell inputs, it could be affected in albinism and thus modify the RGC function. We used the Tyrc/c line, a mouse model of oculocutaneous albinism type 1 (OCA1), carrying a tyrosinase mutation, and previously characterized by a total absence of pigment and severe visual deficits. To assess their retinal function, we recorded the light responses of hundreds of RGCs ex vivo using multi-electrode array (MEA). We estimated the receptive field (RF)-center diameter of Tyr+/c and Tyrc/c RGCs using a checkerboard stimulation before simultaneously stimulating the center and surround of RGC RFs with full-field flashes. Following checkerboard stimulation, the RF-center diameters of RGCs were indistinguishable between Tyrc/c and Tyr+/c retinas. Nevertheless, RGCs from Tyrc/c retinas presented more OFF responses to full-field flashes than RGCs from Tyr+/c retinas. Unlike Tyr+/c retinas, very few OFF-center RGCs switched polarity to ON or ON-OFF responses after full-field flashes in Tyrc/c retinas, suggesting a different surround suppression in these retinas. The retinal output signal is affected in Tyrc/c retinas, despite intact RF-center diameters of their RGCs. Adaptive mechanisms during development are probably responsible for this change in RGC responses, related to the absence of ocular pigments.

Assessing open-pit mining impacts on semi-arid grassland: A framework for boundary and intensity quantification

Coal mining in northern China's grasslands faces significant environmental challenges due to the fragile semi-arid ecosystem and the abundance of mineral resources. However, current research lacks clarity in both theoretical understanding and effective quantification of its impacts. Insufficient distinction between direct and indirect environmental effects, the oversight of interactions from neighboring activities, and inaccurate measurements of impact intensity all hinder a comprehensive understanding. These limitations also prevent the precise delineation of ecological protection compensation areas. In this study, we developed a comprehensive framework utilizing Landsat time-series images (1989–2017) and field sampling data (228 sample locations in 2017) to assess the boundaries and intensities of mining impacts. First, the k-means clustering algorithm was applied to identify the Normalized Difference Vegetation Index (NDVI) time-series trajectories and map the spatial information of direct impacts. Then, a buffer zone was established and an amplitude model was proposed for determined the cross-impacts and their intensities based on the volatility of NDVI trajectories. Accordingly, a Trend-thresholds model was proposed to automatically extract the indirect impacts boundary of mining-dominated on vegetation under varying intensities. The Soil Quality Index (SQI) ∼ distance curves were fitted and a derivative model was employed for determine the boundary of indirect impacted on soil. We applied this assess framework in Baorixile coalfield (i.e., Baorixile coal mine (BM), DongMing coal mine (DM), Shunxing coal mine (SX)) a typical semi-arid grassland mining area, and quantified three types of impacts: direct, indirect, and cross-impacts. Findings reveal negative coal mining impacts primarily confined to permitted mining areas and decreasing over time. Direct impacts boundary limited in the mining sites and its impact intensity shows a dual nature, with a negative weakening and a positive strengthening trend. Widespread negative indirect impacts exist outward the mining area displays spatial heterogeneity, and its intensity attenuation with distances. In there, the very severe effect (D1) is predominantly focusing on the grassland where near by the mining work face (BM maximum range 1.2 km, DM maximum range 0.55 km, SX maximum range 0.4 km). Moreover, our study indicated that vegetation and soil exhibited consistent responses to coal mining impacts within 1 km, demonstrating the feasibility of using remote sensing data to qualify the impact boundary on the grassland environment. Besides, we further identify significant cross-impacts surrounding the mining areas, characterized by strong negative effects, particularly in the southeastern region of BM. This research offers valuable insights for effective ecological compensation governance and scientific environmental management in similar global contexts.

Chironomids regulate long‐chain polyunsaturated fatty acid levels independent of lake nutrient or dissolved organic carbon concentrations

Chironomids are keystone primary benthic consumers with semi‐aquatic life cycles. They support aquatic and terrestrial consumers at higher trophic levels by conveying dietary nutrients, such as fatty acids. In this study, we combined field sampling and laboratory experiments to examine the effects of environmental parameters, including diet, on fatty acid composition and metabolism in chironomid larvae and imagines. Results from 53 lakes showed that lake size, depth, dissolved organic carbon (DOC) concentrations, and trophic state had only marginal effects on the content of long‐chain polyunsaturated fatty acids (LC‐PUFA) in chironomids. Compound‐specific stable hydrogen isotope analyses confirmed that chironomids actively bioconvert dietary fatty acid precursors to LC‐PUFA in all lake types, independent of nutrient or DOC concentrations. Moreover, fatty acid‐specific stable carbon isotope data indicated that the diet of chironomids was subsidized, particularly in oligotrophic lakes in spring, by terrestrial C18 fatty acid precursors that were converted to LC‐PUFA. Data from feeding experiments further confirmed that decreased dietary availability of LC‐PUFA enhanced the conversion of dietary short‐chain precursors to LC‐PUFA. These results suggest that chironomids are PUFA regulators that can sustain LC‐PUFA levels under varying environmental conditions. Furthermore, our results indicate that they bioconvert terrestrial low‐quality material to high‐quality resources, which, via chironomid emergence, support terrestrial food webs. Chironomids are abundant and widespread, and thus, the trophic transfer of LC‐PUFA can have significant implications for the fitness and production of upper trophic level consumers in both aquatic and terrestrial ecosystems.

Hunting pressure on primates in the southern portion of the Brazilian Northeast: historical threats and current perspectives

Hunting is an ancient human behavior, which likely became complex and efficient gradually through time. We present data from a bibliographic survey (qualitative) and field sampling (quantitative) of primate hunting in Northeastern Brazil. We evaluated hunting threats faced by 14 primate species native to the States of Bahia and Sergipe (three Critically Endangered, three Endangered, three Vulnerable, two Near Threatened, and three Least Concern). Qualitatively, since 2005, we identified 21 academic studies that contained 47 mentions of all six studied genera known to occur in the study area (Alouatta=4, Brachyteles=2, Callicebus=16, Callithrix=8, Leontopithecus=3, Sapajus=14). Approximately half of the citations were for hunting (55.3%; 88.4% of this for bushmeat) and the other half for trapping (44.7%; 90.4% for pet). Quantitatively, we obtained 834 local experts’ citations of primate hunting and capturing at 348 sites. All experts cited Callithrix, 818 cited Sapajus, and 738 cited Callicebus. We argued 539 about hunting for bushmeat (164 positive; 30.4%) and 636 about trapping for pet (189 positive; 30.9%). Callicebus presented 95 citations as bushmeat (30.1% of 326 queries) and Sapajus presented 80 citations as pet (35.7% of 224). Four informants reported hunting Sapajus for pest control because of crop damage. There was a significant difference (Chi²=33.982; df=2; p&lt;0.0001) comparing hunting for bushmeat and pets, with Callicebus (higher bushmeat) and Sapajus (higher pet) presenting significant differences (both p&lt;0.01). The impact of hunting is associated with biological contexts, besides socioeconomic and political, requiring complex-specific attention and efforts in conservation and management strategies, perhaps innovative, even non-prohibitive.

Sensitive and modular amplicon sequencing of Plasmodium falciparum diversity and resistance for research and public health.

Targeted amplicon sequencing is a powerful and efficient tool to interrogate the P. falciparum genome and generate actionable data from infections to complement traditional malaria epidemiology. For maximum impact, genomic tools should be multi-purpose, robust, sensitive and reproducible. We developed, characterized, and implemented MAD4HatTeR, an amplicon sequencing panel based on Multiplex Amplicons for Drug, Diagnostic, Diversity, and Differentiation Haplotypes using Targeted Resequencing, along with a bioinformatic pipeline for data analysis. MAD4HatTeR targets 165 highly diverse loci, focusing on multiallelic microhaplotypes; key markers for drug and diagnostic resistance, including duplications and deletions; and csp and potential vaccine targets. In addition, it can detect non-falciparum Plasmodium species. We used laboratory control and field sample data to demonstrate the high sensitivity and robustness of the panel. The successful implementation of this method in five laboratories, including three in malaria-endemic African countries, showcases its feasibility in generating reproducible data across laboratories. Finally, we introduce an analytical approach to detect gene duplications and deletions from amplicon sequencing data. MAD4HatTeR is thus a powerful research tool and a robust resource for malaria public health surveillance and control.

Influence of Field Sampling Methods on Measuring Volatile Organic Compounds in a Swine Facility Using SUMMA Canisters

Influence of Field Sampling Methods on Measuring Volatile Organic Compounds in a Swine Facility Using SUMMA Canisters

Integration of bare soil and crop growth remote sensing data to improve the accuracy of soil organic matter mapping in black soil areas

Accurately mapping the spatial distribution of soil organic matter (SOM) content is critical for informed land management decisions and comprehensive climate change analyses. Remote sensing-based SOM mapping models during periods of bare soil exposure have demonstrated efficacy in various regional studies. However, integrating bare soil imagery with growing season imagery for SOM content mapping remains a complex process. We conducted a study in Youyi Farm, a representative area of black soil in Northeast China. We collected 574 soil samples (0–20 cm) with SOM content through field sampling and laboratory analysis. Additionally, cloud-free Sentinel-2 images were obtained from the Google Earth Engine (GEE) platform for both the bare soil period (April-June, October) and crop growth period (July-September) from 2019 to 2021. To assess the influence of crop growth information on SOM mapping, we incorporated remote sensing imagery during the crop growth period, considering different crop type zones (maize (Zea mays L.), soybean (Glycine max L.), and rice (Oryza sativa L.)). We conducted overall and zonal regressions using the random forest (RF) model to validate the prediction results through cross-validation. Our findings indicate that: (1) adding crop growth period images to the bare soil period images in different years can improve the accuracy of SOM mapping. For example, in the overall regression model of 2020, the highest accuracy was achieved by using the combination of May-July images, with an R2 value of 0.70 and an RMSE value of 0.71 %; (2) zonal regression by differentiating crop types can effectively improve the SOM mapping accuracy. In 2019, using zonal regression, the R2 of SOM mapping accuracy was improved by 0.02 and the RMSE was reduced by 0.03 % compared with the overall regression; (3) precipitation is an important factor affecting the accuracy of SOM prediction, and the lower the precipitation, the higher the accuracy of SOM prediction. In summary, the results of this study show that in the SOM remote sensing mapping of the black soil area, the growing period remote sensing information of different crop types should be comprehensively considered and combined with the image data of the years of lower precipitation, the accuracy of the SOM mapping can be effectively improved, which provides a new technological path and an application basis for the enhancement of the accuracy in remote sensing mapping with soil attributes.

Assessing fecal contamination from human and environmental sources using Escherichia coli as an indicator in rural eastern Ethiopian households - a study from the EXCAM project.

Enteric pathogens are a leading causes of diarrheal deaths in low- and middle-income countries. The Exposure Assessment of Campylobacter Infections in Rural Ethiopia (EXCAM) project, aims to identify potential sources of bacteria in the genus Campylobacter and, more generally, fecal contamination of infants during the first 1.5 years of life using Escherichia coli as indicator. A total of 1,310 samples (i.e., hand rinses from the infant, sibling and mother, drinking and bathing water, food and fomite provided to or touched by the infants, areola swabs, breast milk and soil) were collected from 76 households between May 2021 and June 2022. Samples were assigned to two groups by infant age: TP1 (time point 1), infants between 4 and 8 months of age, and TP2, infants between 11 and 15 months of age. Fluorometric and semi-selective colorimetric approaches were used to quantify E. coli in the field samples. Overall, E. coli was ubiquitous within selected households (56.8% across the study). E. coli was more frequently detected than average (>53%) with high concentration (>2-log CFU) in soil (g) and per pair of hand, while the opposite trend (<33%; <1.5-log CFU) was observed in food provided to the infants (g or ml), per areola, and breast milk (ml; P<0.01). E. coli was frequently detected in fomites touched by the infants, drinking and bathing water (>51%), but at low concentration (<1.5-log CFU). Correlation analysis between E. coli concentration in different sample types suggested that the mother's hands might play a key role in the transmission of E. coli between the environment (i.e., soil, bathing water and fomites) and other family members (i.e., infant and sibling; P<0.04; r2>0.3). Using E. coli as surrogate, our study identified mother (hands and areola) as reservoirs likely to be involved in frequent transmission of fecal contaminants to infants within rural Ethiopian households.

Removal of heavy metals from mine water using a hybrid electrocoagulation-ceramic membrane filtration process

Mining operations must account for increasingly stringent wastewater discharge limits for various contaminants, such as heavy metals and suspended solids. In the treatment of metal-bearing wastes, electrochemical processes, including electrocoagulation (EC), are gaining popularity. At large scales, EC processes can be hindered by considerable amounts of flocculants and by sedimentation tank sizes required to properly operate. This work sought to address these concerns by evaluating EC in mine water treatment using a pilot system coupled with ceramic membrane microfiltration (MF) and ultrafiltration (UF). The use of MF and UF after EC allows for the removal of suspended solids without needing a flocculation-sedimentation process. EC evaluation was performed using field samples of mine water from a North American concentrator. Under optimal conditions, EC removed over 95 % of Cr, Co, Cu, Fe, Mn, Ni, Pb, Ti and Zn from the mine water. Effluent from EC was used as feed in MF and UF processes with ceramic membranes. The tested membranes rejected 100 % of suspended solids from the EC effluent. Permeate from the membranes was free of solids and possessed turbidities of 0.05–0.15 NTU. Filtrate from the hybrid process satisfied environmental regulations for heavy metal concentrations, offering new opportunities for reuse or discharge. The hybrid process applied in this work can thus be used in mining operations to safely discharge their water, and/or to increase their water recirculation due to environmental concerns and water shortage.

Complementary studies of the Perlidae (Insecta: Plecoptera) fauna from the Paranapiacaba Mountains using DNA barcode data

The Paranapiacaba Mountains are a region of Brazil where the stonefly fauna is relatively well known. Despite this, there are still gaps in knowledge that need to be filled. In this study, through field sampling and molecular analyses, we have updated the taxonomic knowledge of Perlidae species in this region. Our study employed DNA barcoding methods to complement traditional morphological approaches, facilitating the association and description of the nymphs of Anacroneuria itajaimirim Bispo &amp; Froehlich 2004. Additionally, we generated DNA barcode sequences for Anacroneuria iporanga Bispo &amp; Froehlich 2004. Our results contributed to knowledge about Perlidae from the Paranapiacaba Mountains, highlighting the importance of DNA barcode data in the association of immature stages and species delimitations. Although the stoneflies of Paranapiacaba Mountains have been relatively well-studied, our results reveal that we still have deficits in knowledge of the fauna of this region.

Parasitological Examination of the Digestive System of Wild Boar from a Practical Point of View-Endoparasitological Sampling under Field Conditions.

From 2015 to 2023, we conducted a comprehensive study in the 11,893-hectare hunting area managed by the Marcal-Bitvaközi Hunting Company, characterised by its substantial wild boar population. The research was carried out across various settings, including a free-range wild boar garden during large-scale hunts and free-living areas during individual hunts. We examined 216 wild boars in total, with 173 individuals from free-living areas and 43 from free-range areas. Throughout the sample collection process, we encountered numerous technical challenges that are infrequently detailed in the professional literature, often mentioned only tangentially. This oversight in existing publications neglects the significance of addressing field sampling difficulties, which are crucial for ensuring the precision and accuracy of research. This paper details the equipment requirements, sampling methodologies, and practical solutions to streamline fieldwork. While our primary focus was on endoparasitic infections of the stomach and small intestine, the described methodologies and findings are broadly applicable to research involving all internal organs.

Temperature related to the spatial heterogeneity of wetland soil total nitrogen content in a frozen zone

Changes in soil total nitrogen (N) content would affect wetland function and the global N cycle. Determination of spatial heterogeneity controlling factors of wetland soil total N content per unit mass is essential to assess responses of ecosystem N cycle to global change. However, such information is limited in permafrost zones because few soil profiles have been acquired and methods to predict spatial distributions of wetland soil total N content in large areas are inefficient, which increase uncertainty in evaluations of N cycle at national or global scales. To determine the spatial heterogeneity of wetland soil total N content at different soil depths and frozen zones and the factors controlling wetland soil total N content in the frozen zones of Northeast China, the spatial pattern of wetland soil total N content was investigated by using a random forest method that combined field samples with environmental factors. Vertically, wetland soil total N content decreased with increasing soil depth, with the highest content in the top soil layer (0–30 cm). Spatially, wetland soil total N content decreased from northwest to southeast, with relatively high total N content in a continuous permafrost zone and relatively low total N content in a seasonally frozen zone. The overall coefficient of variation of wetland soil total N content in the frozen zones of Northeast was 29.58 %, indicating moderate variation. Land surface temperature, mean annual temperature, and mean annual humidity significantly affected total N content in 0–30 and 30–60 cm soil layers, suggesting that variations in temperature and humidity altered sequestration processes of wetland soil total N content. In the 60–100 cm soil layer, compared with other environmental factors, mean annual humidity, altitude, and mean annual precipitation had the greatest influence on the spatial distribution of wetland soil total N content. The study unravels the spatial pattern of soil total N content in frozen zones of Northeast China and reflects the direct and indirect effects of environmental factors on total N content. This provides a basis for the management and protection of wetland ecosystems.

Testing combined effects of environmental trace metals/arsenic and marine trophic status on the bioaccumulation in Pacific oysters: Insights from 22-site field samplings

Pacific oysters were sampled from 22 human-impacted sites in northeastern Japan to measure Cr, Cu, Zn, Pb, Cd, and As. The hazard quotient was slightly >1 for Cu and/or As at two sites, but <1 for all metal species and As at the other sites, indicating low human health risks. Oysters' Cu, Zn, and Pb contents were positively related to their concentrations in the sediment, while Cr and As were not. Oysters' Cu and Zn were negatively related to the inorganic nitrogen in seawater, while oysters' Pb and As showed positive relationships with the particulate organic carbon. These findings suggest that marine trophic status affects oysters' metal uptake differently among the metal species. Furthermore, oysters' Cr, Cu, Zn, and Pb contents were negatively related to their eicosapentaenoic acid content and condition index. Therefore, the nutritional conditions of oysters may influence their elimination or accumulation of these metals.

Segmentation of beach plastic fragments’ contours based on self-organizing map and multi-shape descriptors: A rapid indication of fragmentation and wearing types

Environmental plastic fragments have been verified as byproducts of large plastic and its secondary pollutants including micro and nanoplastics. There are few quantitative studies available, but their contours have values for the weathering mechanisms. We used geometric descriptors, fractal dimensions, and Fourier descriptors to characterize field and artificial polyethylene and polypropylene samples as a means of investigating the contour characteristics. It provides a methodological framework for contour classification. Unsupervised classification was performed using self-organizing neural networks with size-invariance parameters. We revealed the isometric phenomenon of plastic fragments during fragmentation, i.e., that the degree of contour rounding and complexity increase and decrease, respectively, with decreasing fragment size. With an average error rate of 8.9 %, we can distinguish artificial samples from field samples. It was also validated by the difference in Carbonyl Index between groups. We propose a two-stage process for plastic fragmentation and give three types of contour features which were key in the description of fragmented contours, i.e., size, complexity, and rounding. Our work will improve the accuracy of characterizations regarding the weathering and fragmentation processes of certain kinds of plastic fragments. The contour parameters also have the potential to be applied in more realistic scenarios and varied polymers.

Population structure, spatial aggregation, and sampling plan for the Texas citrus mite, Eutetranychus banksi (Acari: Tetranychidae) on citrus.

Eutetranychus banksi (McGregor) (Acari: Tetranychidae) is an invasive spider mite native to the Americas. In 2013 it invaded the main citrus-growing area in Spain producing significant damage and requiring chemical treatments. This work examines its population structure, spatial distribution and presents a sampling plan, which will assist in developing an integrated pest management (IPM) strategy. There were differences in the population structure on fruits and leaves, as well as between leaves from different flushes with fluctuations over time correlated with variations in sex ratio. No differences in aggregation at the different plant strata were found; however, immature stages showed a higher aggregation than adults, with females being the sex with the lowest aggregation. There was a high correlation between E. banksi motile forms and adult females with the total population, thus both were used as reference stages to develop sampling plans. We recommend binomial sampling of 100 leaves for female monitoring, sampling two leaves per tree on 25 trees per transect regularly spaced along two diagonal transects, the first oriented northeast to southwest and the second northwest to southeast. To be more accurate, it is possible to survey the presence/absence of motile forms. In this case, four leaves per tree in 50 trees per transect should be monitored. This study has resulted in the first sampling plan for E. banksi, one of the most damaging citrus mite species described so far. The binomial sampling plan involves monitoring reference developmental stages, as well as a reasonable sample size that makes it applicable in field sampling for decisions making based on a future intervention threshold. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Plants, fungi, and carabid beetles in temperate forests: both observed and dark diversity depend on habitat availability in space and time

ContextThe loss of ancient forests threatens many species. Effective nature conservation needs information on how forest availability in the surrounding landscape in space and time determines the diversity of multiple taxa.ObjectivesWe explored the relationship between forest availability at different spatiotemporal scales and the diversity of various groups: vascular plants (woody species, ground layer), epiphytes (bryophytes and lichens), fungi (ectomycorrhizal, arbuscular mycorrhizal, pathogenic, saprotrophic), and carabid beetles. Besides the observed diversity, we also estimated dark diversity, i.e. suitable but absent species. Dark diversity is theoretically a sensitive metric in detecting ecosystem conditions as it is typically relatively large and contains susceptible species.MethodsWe recorded the observed diversity by field sampling and soil DNA in 100 temperate ancient old-growth forest sites in southern Estonia; dark diversity was estimated for the same sites using species co-occurrence data. Forest availability estimates were obtained from four topographic maps (1900s-2010s) at the 0.5–5 km radius.ResultsThe biodiversity of forest specialists was higher at larger historical forest availability at the spatial scale of 2–5 km radius. The diversity of light-demanding forest ecotone taxa mainly had negative relationships with young forests on previous agricultural lands (at 0.5–2 km radius). Dark diversity models were often more strongly associated with forest availability than observed diversity models.ConclusionsDark diversity enhances our understanding of how current and historical forest availability affects local biodiversity. As young forests cannot provide suitable habitats for many forest-dwelling species, stable forest habitats must be preserved as source areas to enhance biodiversity.

Alternative for HPC22 after repairs in the drinking water distribution system

There is a risk of contamination by (pathogenic) microorganisms from the outside environment into the drinking water during maintenance or pipe breaches in the drinking water distribution system (DWDS) and, consequently, the drinking water distributed to consumers may result in possible detrimental effects on public health. Traditional time-consuming microbiological testing is, therefore, performed to confirm drinking water is not microbially contaminated. This is done by culturing methods of the faecal indicators Escherichia coli, intestinal enterococci and the technical parameters coliform bacteria and heterotrophic plate counts at 22 °C (HPC22). In this study, fast methods (adenosine triphosphate (ATP), flow cytometry, enzyme activity and qPCR) were compared as an alternative for HPC22. Using dilution series and field samples, ATP (ATPtotal-lab and ATPcell-mob) and enzymatic activity (ALP-2) methods proved to be the more reliable and sensitive than flow cytometry and qPCR methods for detecting microbiological contaminations in drinking water. Significant (p < 0.05) and relatively strong correlations (R2 = 0.61–0.76) were obtained between HPC22 and both ATP methods, enzyme activity and qPCR parameters, but relations with flow cytometry were weak (R2 = 0.24 – 0.52). The samples taken after repairs or a calamity from the DWDS showed in general limited variation in the HPC22 count and were in most cases below the guidance level of 1,000 CFU/mL. We recommend that the best performing alternative methods, i.e. ATPtotal-lab and ATPcell-mob and ALP-2, should be included next to HPC22 in additional field studies to further test and compare these methods to be able to decide which fast method can replace HPC22 analysis after maintenance work in the DWDS.