Current Distribution Data Research Articles

Potential distribution of Spodoptera frugiperda (J.E. Smith) in China and the major factors influencing distribution

Fall armyworm, Spodoptera frugiperda (J.E. Smith) is one of the most important agricultural pests in the world. At the end of 2018, S. frugiperda was first found in Yunnan, China, and then it had spread rapidly to 19 provinces and posed a serious threat to China’s agricultural production. Based on the current distribution data of S. frugiperda and enviromental variables, this paper constructed a potential species distribution model (MaxEnt), and predicted the potential distribution area of S. frugiperda in China, and identified the dominant climatic factors that control its distribution. The results showed that: (1) The average AUC value of the model was 0.906, which demonstrated that the accuracy of the model was excellent. (2) Mean Temperature of Coldest Quarter (bio11), Min Temperature of Coldest Month (bio6), Mean Temperature of Warmest Quarter (bio10), Max Temperature of Warmest Month (bio5), were dominant climatic factors which affected and controlled the potential distribution of S. frugiperda, and the appropriate range were −14.77-22.86 °C, −13.33-24.35 °C, 19.15–29.73 °C, and 24.55–36.83 °C. (3) The most suitable area of S. frugiperda are mainly distributed in Guangxi, Jiangxi, Guangdong, Hunan, Fujian, Zhejiang, Yunnan, Hubei, Anhui, Sichuan, Chongqing, Hainan, Jiangsu, Henan, Taiwan, Guizhou, Shaanxi, Shanghai and Hongkong, and account for 12.09% of China’s total area. According to the results of this study, it was known that the pest was a major threat to maize and rice in China, and it was urgently necessary to strengthen monitoring and management in its suitable range to prevent the invasion of S. frugiperda which would ensure the safety of agriculture.

Pinhole Effect Investigation in Electrowetting Dielectrics by Current Density Measurements

In this paper, we use current density measurement as an important diagnostic method to study the reliability of electrowetting devices. The current density distribution data is closely related to the early detection of malfunctions or failures in the devices. Here we use segmented cell technology to investigate the current density distributions in the top substrate to determine the initiation of dielectric breakdown. The current density measurements are further used to determine the signature of pinhole formation in the dielectric film. Different behavior is observed for dielectric failure under DC and AC voltages, and a sudden current change associated with vaporization of water is assumed to trigger the failure of the device.

New species of Inocybe (Inocybaceae) from eastern North America1

Five species of Inocybe from eastern North America are described as new: Inocybe carolinensis, Inocybe dulciolens, Inocybe friabilis, Inocybe glaucescens, and Inocybe vinaceobrunnea. Inocybe carolinensis is a new species in Inocybe sect. Inocybe; I. dulciolens and I. glaucescens are two new species in Inocybe sect. Lactiferae; I. friabilis is described as new in the Pseudosperma clade (Inocybe sect. Rimosae sensu stricto); and I. vinaceobrunnea is newly described for I. jurana sensu Hesler in the Inosperma clade (Inocybe sect. Rimosae sensu lato). At least four of the five species are endemic to regions of eastern North America based on current distribution data. ITS, 28S rDNA, rpb2, and rpb1 genes, in combination with morphological and ecological traits, are used to aid in species recognition. Phylogenetic trees, taxonomic descriptions, and illustrations are provided.

Combined effects of climate change and sea-level rise project dramatic habitat loss of the globally endangered Bengal tiger in the Bangladesh Sundarbans

The Sundarbans, in southern coastal Bangladesh, is the world's largest surviving mangrove habitat and the last stronghold of tiger adapted to living in a mangrove ecosystem. Using MaxEnt (maximum entropy modeling), current distribution data, land-use/land cover and bioclimatic variables, we modeled the likely future distribution of the globally endangered Bengal tiger (Panthera tigris tigris) in the Bangladesh Sundarbans. We used two climatic scenarios (i.e., RCP6.0 and RCP8.5) developed by the Intergovernmental Panel on Climate Change (IPCC) to provide projections of suitable habitats of Bengal tigers in 2050 and 2070. We also combined projected sea-level rise for the area in our models of future species distributions. Our results suggest that there will be a dramatic decline in suitable Bengal tiger habitats in the Bangladesh Sundarbans. Other than various aspects of local climate, sea-level rise is projected to have a substantial negative impact on Bengal tiger habitats in this low-lying area. Our model predicts that due to the combined effect of climate change and sea-level rise, there will be no suitable Bengal tiger habitat remaining in the Sundarbans by 2070. Enhancing terrestrial protected area coverage, regular monitoring, law enforcement, awareness-building among local residents among the key strategies needed to ensure long-term survival and conservation of the Bengal tiger in the Bangladesh Sundarbans.

Zinc layer anode applied on reinforced concrete structures

The application of zinc layer anode to reinforced concrete structure has been well known for many years. This galvanic cathodic protection system was specified being a corrosion control system for general steel in concrete as well as civil structures. A good way to determine the dimensioning elements of the galvanic protection system, is to carry out a pilot test being monitored in situ, and exposed under on site conditions including local concrete remediation or repair works. This paper presents an analysis of the current distribution and steel polarization data that have been collected from a car park project in the French Alps.

Current Distribution Method of Induction Motor for Electric Vehicle in Whole Speed Range Based on Gaussian Process

A current distribution method based on Gaussian process is proposed in this paper. This method can improve the accuracy of current distribution of induction motors for electric vehicles in whole speed range, and achieve high-performance output torque. First, a vector control system based on current distribution model is designed based on control requirement analysis of induction motor. Second, the mathematical model of output torque and current is established. And the current distribution law of the optimal electromagnetic torque under various operating conditions is qualitatively analyzed. Third, the experimental platform is built to obtain the discrete data of current distribution in whole speed range and the rotor time constants at different temperatures. Finally, the Gaussian process is introduced to establish the regression model based on current discrete data. The regression model distributes the current reasonably and accurately, which is embedded in the control system. Experimental results verify the effectiveness of the proposed method.

Method of current distribution parameters measuring with using reference magnetic field source

The method for measurement of current distribution parameters is described in this work. Main feature of the method is compensation of magnetometer errors by using reference distribution. The measurement errors are compensated by using the error model parameters. The parameters are fitted on reference current distribution data. The method was tested on 3-axis Hall magnetometer with motorized positioning system. Its absolute accuracy is about 5 µm and dynamic range is 20 × 200 × 300 mm3. Sensitivity of the magnetometer is about 1 nT on averaging time of 5 s. Measurement error coordinate and magnetic moment of a circular current loop are not more than 5 µm by and 10–8 A⋅m2 accordingly.

The status of African elephant Loxodonta africana populations in South Africa

AbstractWith an increase in poaching of elephants Loxodonta africana across Africa, it is vital to know exactly how many elephants remain and where they occur, to ensure that protection and management are planned appropriately. From a nationwide survey we provide current population and distribution data for elephants in South Africa. We consider the viability of elephant populations in the country, as well as some of the management techniques implemented and how effective these are in controlling elephant numbers. According to our surveys there were 28,168 elephants in South Africa as of December 2015, with 78% of these occurring in Kruger National Park and reserves bordering and open to the Park. Of the country's 78 discrete reserves that host elephants, 77% have populations of < 100 elephants, which could mean they are not genetically viable. We discuss our findings in terms of the conservation value of South Africa's elephant reserves, and the animal welfare implications. We recommend that the fragmentation of elephant habitat in the country be addressed through a national elephant management strategy that promotes wildlife corridors between existing, neighbouring elephant reserves.

Linking species thermal tolerance to elevational range shifts in upland dung beetles

Climate warming has been proposed as the main cause of the recent range shifts seen in many species. Although species' thermal tolerances are thought to play a key role in determining responses to climate change, especially in ectotherms, empirical evidence is still limited. We investigate the connection between species' thermal tolerances, elevational range and shifts in the lower elevational limit of dung beetle species (Coleoptera, Aphodiidea) in an upland region in the northwest of England. We measured thermal tolerances in the laboratory, and used current and historical distribution data to test specific hypotheses about the area's three dominant species, particularly the species most likely to suffer from warming: Agollinus lapponum. We found marked differences between species in their minimum and maximum thermal tolerance and in their elevational range and patterns of abundance. Overall, differences in thermal limits among species matched the abundance patterns along the elevation gradient expected if distributions were constrained by climate. Agollinus lapponum abundance increased with elevation and this species showed lower maximum and minimum thermal limits than Acrossus depressus, for which abundance declined with elevation. Consistent with lower tolerance to high temperature, we recorded an uphill retreat of the low elevation limit of A. lapponum (177 m over 57 yr) in line with the increase in summer temperature observed in the region over the same period. Moreover, this species has been replaced at low and mid‐elevations by the other two warm‐tolerant species (A. depressus and Agrilinus ater). Our results provide empirical evidence that species' thermal tolerance constrains elevational ranges and contributes to explain the observed responses to climate warming. A mechanistic understanding of how climate change directly affects species, such as the one presented here, will provide a robust base to inform predictions of how individual species and whole assemblages may change in the future.

Snub-nosed monkeys (Rhinopithecus): potential distribution and its implication for conservation

Many threatened species have undergone range retraction, and are confined to small fragmented populations. To increase their survival prospects, it is necessary to find suitable habitat outside their current range, to increase and interconnect populations. Species distribution models may be used to this purpose and can be an important part of the conservation strategies. One pitfall is that such mapping will typically assume that the current distribution represents the optimal habitat, which may not be the case for threatened species. Here, we use maximum entropy modelling (Maxent) and rectilinear bioclimatic envelope modelling with current and historical distribution data, together with the location of protected areas, and environmental and anthropogenic variables, to answer three key questions for the conservation of Rhinopithecus, a highly endangered genus of primates consisting of five species of which three are endemic to China, one is endemic to China and Myanmar and one is endemic to Vietnam; Which environmental variables best predict the distribution? To what extent is Rhinopithecus living in an anthropogenically truncated niche space? What is the genus’ potential distribution in the region? Mean temperature of coldest and warmest quarter together with annual precipitation and precipitation during the driest quarter were the variables that best explained Rhinopithecus’ distribution. The historical records were generally in warmer and wetter areas and in lower elevation than the current distribution, strongly suggesting that Rhinopithecus today survives in an anthropogenic truncated niche space. There is 305,800–319,325 km2 of climatic suitable area within protected areas in China, of which 96,525–100,275 km2 and 17,175–17,550 km2 have tree cover above 50 and 75%, respectively. The models also show that the area predicted as climatic suitable using Maxent was 72–89% larger when historical records were included. Our results emphasise the importance of considering historical records when assessing restoration potential and show that there is high potential for restoring Rhinopithecus to parts of its former range.

Potential Geographic Distribution of Palmer Amaranth under Current and Future Climates

Core Ideas CLIMEX model projections match known Palmer amaranth distribution. Sub‐Sahara Africa and Australia are at risk for Palmer amaranth establishment. Future climate scenarios indicate the potential for poleward range expansion. Herbicide‐resistant weeds are increasingly becoming a major challenge for agricultural production worldwide. Palmer amaranth [Amaranthus palmeri (S.) Wats.] is an invasive annual forb that has recently emerged as one of the most widespread and severe agronomic weeds in the United States, due in part to its facility for evolving herbicide resistance. It has invaded several parts of the world, including key agricultural production regions in South America. Climate change will likely exacerbate the challenges of managing this species. To assess this, we developed a process‐oriented bioclimatic niche model of Palmer amaranth to examine its potential global distribution under current conditions and future climate scenarios. The model agreed well with all credible current distribution data. Projected future increases in temperatures will expand potential Palmer amaranth range northward into portions of Canada and Europe. Model projections under current and future climates highlight several agricultural production regions of increasing and emerging risk from this weed.

Survey and protective utilization of Lycium ruthenicum resources distributed in middle and lower reaches of Heihe river

This study was aimed to investigate the qualitative and quantitative distributions of Lycium ruthenicum resources in the middle and lower reaches of Heihe River, for providing scientific evidence for the protective utilization of the resources in the corresponding geographic region. The outdoor sample plot and quadrat survey, literature search, sample collection, in-house identification and classification were performed by route surveying and visiting to the local natives and/or herb farmers based on the current distribution data of the L. ruthenicum resources in the middle and lower reaches of Heihe River. The distributive pattern of the resources was analyzed using ArcGIS program. The data regarding the category/distributed area and the genetic resources of the L. ruthenicum were collected. The data collected in this study may provide the scientific evidence for the protective utilization of the L. ruthenicum resources in the corresponding geographic region, allowing for the avoidance of the ecological environment from being damaged by improper utilization.

Cryptic diversity and speciation in endemic Cytherissa (Ostracoda, Crustacea) from Lake Baikal

Lake Baikal (Siberia) is the most ancient and deepest of all ancient lakes on Earth. It holds a (mostly endemic) diversity of thousands of animal species, including a speciose radiation of ostracods of the genus Cytherissa. Applying molecular tools to this crustacean group reveals that several morphological species are actually species clusters. Based on combined 16S and 28S DNA sequence data from thirteen classic Cytherissa species and one subspecies sensu Mazepova (1990), we recognize 26 different genetic Cytherissa species, 18 with morphological variation and eight truly cryptic species. These results suggest that the actual specific diversity of Cytherissa in Lake Baikal might easily be double of what is presently known. Baikalian endemic species most likely live in the cradle in which they originated and this opens perspectives to infer modes of speciation. Our current distribution data of Cytherissa species provide first indications for both geographic (lakes basins and shores) and ecological (sediment type, water depth) separation. Our present data thus provide the first steps towards future, rigorous testing of focussed hypotheses on the causality of speciation through either allopatric isolation or parapatric ecological clines.

A sensitive environmental DNA (eDNA) assay leads to new insights on Ruffe (Gymnocephalus cernua) spread in North America

Detection of invasive species before or soon after they establish in novel environments is critical to prevent widespread ecological and economic impacts. Environmental DNA (eDNA) surveillance and monitoring is an approach to improve early detection efforts. Here we describe a large-scale conservation application of a quantitative polymerase chain reaction assay with a case study for surveillance of a federally listed nuisance species (Ruffe, Gymnocephalus cernua) in the Laurentian Great Lakes. Using current Ruffe distribution data and predictions of future Ruffe spread derived from a recently developed model of ballast-mediated dispersal in US waters of the Great Lakes, we designed an eDNA surveillance study to target Ruffe at the putative leading edge of the invasion. We report a much more advanced invasion front for Ruffe than has been indicated by conventional surveillance methods and we quantify rates of false negative detections (i.e. failure to detect DNA when it is present in a sample). Our results highlight the important role of eDNA surveillance as a sensitive tool to improve early detection efforts for aquatic invasive species and draw attention to the need for an improved understanding of detection errors. Based on axes that reflect the weight of eDNA evidence of species presence and the likelihood of secondary spread, we suggest a two-dimensional conceptual model that management agencies might find useful in considering responses to eDNA detections.

Effectiveness of Local Biodiversity Action Plans to Identify Locally Rare and Endangered Fish in Scotland

Biodiversity loss is an important environmental issue globally. Local Biodiversity Action Plans (LBAPs) provide an important conservation tool and should represent national priority species where they are present. Although much effort has gone in to developing LBAPs, their value as a conservation tool has been questioned. Here the effectiveness of the LBAP system to raise awareness of the freshwater fishes of national and international priority in Scotland is tested. Inclusion of freshwater fish in the LBAP suite was evaluated using current distribution data taken from available literature sources. Of the 25 examined LBAPs in Scotland, there were 79 LBAP entries for the 12 priority freshwater fishes found in Scotland. This contrasts with an expectation of 139 entries. Nineteen authorities failed to represent all priority freshwater fish species extant in their geographical boundary. Fourteen authorities provided cover for 50% or less for the species distributed in their area and five authorities included no rare freshwater fish species where one or more was expected. Possible underlying reasons for this mismatch include: frequently changing conservation status and taxonomic blindness of this group. It is plausible to suggest that this low rate of inclusion will have a detrimental effect on the allocation of limited conservation resources.

Current density imaging sequence for monitoring current distribution during delivery of electric pulses in irreversible electroporation.

BackgroundElectroporation is gaining its importance in everyday clinical practice of cancer treatment. For its success it is extremely important that coverage of the target tissue, i.e. treated tumor, with electric field is within the specified range. Therefore, an efficient tool for the electric field monitoring in the tumor during delivery of electroporation pulses is needed. The electric field can be reconstructed by the magnetic resonance electric impedance tomography method from current density distribution data. In this study, the use of current density imaging with MRI for monitoring current density distribution during delivery of irreversible electroporation pulses was demonstrated.MethodsUsing a modified single-shot RARE sequence, where four 3000 V and 100 μs long pulses were included at the start, current distribution between a pair of electrodes inserted in a liver tissue sample was imaged. Two repetitions of the sequence with phases of refocusing radiofrequency pulses 90° apart were needed to acquire one current density image. For each sample in total 45 current density images were acquired to follow a standard protocol for irreversible electroporation where 90 electric pulses are delivered at 1 Hz.ResultsAcquired current density images showed that the current density in the middle of the sample increased from first to last electric pulses by 60%, i.e. from 8 kA/m2 to 13 kA/m2 and that direction of the current path did not change with repeated electric pulses significantly.ConclusionsThe presented single-shot RARE-based current density imaging sequence was used successfully to image current distribution during delivery of short high-voltage electric pulses. The method has a potential to enable monitoring of tumor coverage by electric field during irreversible electroporation tissue ablation.

Hepatitis C virus genotype and subtype distribution in Chinese chronic hepatitis C patients: nationwide spread of HCV genotypes 3 and 6.

BackgroundHepatitis C virus (HCV) genotype and subtype are related to disease progression and response to antiviral therapy. Current HCV genotype and subtype distribution data, especially for genotypes 3 and 6, are limited in China. Our purpose was to investigate the current HCV genotype and subtype distributions in chronic hepatitis C patients in China.MethodsChronic hepatitis C patients (n = 1012) were enrolled, and demographic information and possible transmission risk factors were collected. Serum samples were subjected to reverse-transcription polymerase chain reaction, followed by direct DNA sequencing and phylogenetic analysis of the NS5B and core/E1 regions to determine HCV genotypes/subtypes. The geographical distributions of HCV genotypes/subtypes were analyzed. Demographic information and transmission risk factors were compared between different HCV genotypes/subtypes.ResultsFour genotypes and seven subtypes of HCV were detected in 970 patients. Subtypes 1b, 2a, 3a, 6a, 3b, 6n, and 1a were detected at frequencies of 71.96 %, 19.90 %, 3.20 %, 2.16 %, 1.96 %, 0.41 %, and 0.41 %, respectively. Genotypes 3 and 6 showed an increasingly wide geographic distribution over time. Patients with subtypes 1b and 2a were older than those with 3a, 3b, 6a, and 6n subtypes (p < 0.05 in all subtypes). More genotype 1 and 2 patients underwent blood transfusion than those with genotype 3 (all p < 0.05). More genotype 3 and 6 patients had a history of intravenous drug use than those with genotypes 1 and 2 (all p < 0.05).ConclusionsThough subtypes 1b and 2a are still the most prevalent HCV subtypes in China, genotype 3 and 6 HCV infections have already spread nationwide from southern and western China.Electronic supplementary materialThe online version of this article (doi:10.1186/s12985-015-0341-1) contains supplementary material, which is available to authorized users.

Upland desert late pre-classic Hohokam adaptations in the middle Gila

Late pre-Classic Hohokam (A.D. 750–1150) upland desert adaptations of the middle Gila River Valley in southern Arizona are still rather poorly understood. Current site and feature distribution data from Florence Military Reservation indicate that late pre-Classic groups used the upland or bajada zone in a varied and complex manner. First, a variety of agricultural technology was employed, including floodwater farming, dry farming, and to a lesser degree, simple irrigation-based agriculture. Second, a wide range of occupation types have been encountered in these bajada zones, consisting of villages, farmsteads, field houses, agricultural field sites, and more specialized resource processing sites. And, third, a flexible mobility pattern existed, where primary habitations such as rancheria-like villages and small farmsteads were situated along alluvial fans of Cottonwood Canyon Wash. This habitation zone has produced a diversity of floodwater, dry, and irrigation-based farming practices associated with residential areas, trash mounds, and a ball court; the combination of farming technology and presumed ceremonial features may have contributed to group aggregation, at least on a seasonal basis. From this habitation zone, specialized task groups and domestic units repeatedly used field houses and large agricultural fields out on creosote flats, and smaller dry farming loci, on more elevated ridge tops.

An assessment of the information content of South African alien species databases

National alien species databases indicate the state of a country’s biodiversity and provide useful data for research on invasion biology and the management of invasions. In South Africa there are several different published alien species databases, but these databases were created for different purposes and vary in completeness and information content. We assessed the information content of published South African alien species databases in the context of other such databases globally, and evaluated how the information content of South African databases varies across taxonomic groups. Although introduction pathway, date of introduction, region of origin and current broad-scale distribution data are available for most taxonomic groups assessed (60% – 90%), data on invasion status, introduction effort and introduction source are available for few taxonomic groups (5% – 18%). South African alien species databases have lower information content than the detailed databases available in other parts of the world and thus cannot be utilised to the same extent. We conclude with 11 recommendations for improving South African alien species databases. In particular, we highlight the data types that should be incorporated in future databases and argue that existing data should be collated in a single, standardised meta-database to facilitate cross-taxon comparisons, highlight gaps in effort, and inform managers and policy makers concerned with alien species.

Study on Variability of Residual Current and Salinity Structure According to River Discharge at the Yeoungsan River Estuary, South Korea

The Yeoungsan River Estuary (YRE) made change of estuarine circulation environment at not only control of inflow of freshwater but also decreasing tide speed under construction of estuary bank. The estuarine circulation in the estuary made change rapidly at discharge of the estuary bank. We investigated variation of salinity and residual current in study area during freshwater discharge and non-discharge period. To determine effect of artificial freshwater discharge on the spatial and temporal variability of the residual current and salinity distribution, current and density profile data were analyzed in partially stratified YRE. The current and density data, obtained from two cross-sectional transects, was conducted during freshwater discharge and non-freshwater discharge. We observed flow rate and salt during 13h with 1h interval to investigate changes of marine environment. The residual current structure is complex, such as multi-layer, during non-freshwater discharge because tides and wind effects combined with topography influences. Strong freshwater discharge is influences to vertical mixing at the surface layer,however freshwater is not effected at the bottom layer. These distinction of freshwater effect causes the salinity gradient and strongly stratification. Freshwateris toward to open-sea through surface layer during freshwater discharge period. In other words, the distinction of residual current and the stratification are controlled according to whether artificial freshwater discharge or not.