Analysis Of Environmental Variables Research Articles

Analysis of environmental variables and deforestation in the amazon using logistical regression models.

In this study, we applied a multivariate logistic regression model to identify deforested areas and evaluate the current effects on environmental variables in the Brazilian state of Rondônia, located in the southwestern Amazon region using data from the MODIS/Terra sensor. The variables albedo, temperature, evapotranspiration, vegetation index, and gross primary productivity were analyzed from 2000 to 2022, with surface type data from the PRODES project as the dependent variable. The accuracy of the models was evaluated by the parameters area under the curve (AUC), pseudo R2, and Akaike information criterion, in addition to statistical tests. The results indicated that deforested areas had higher albedo (25%) and higher surface temperatures (3.2°C) compared to forested areas. There was a significant reduction of the EVI (16%), indicating water stress, and a decrease in GPP (18%) and ETr (23%) due to the loss of plant biomass. The most precise model (91.6%) included only surface temperature and albedo, providing important information about the environmental impacts of deforestation in humid tropical regions.

Measurement of innovation efficiency in logistic enterprises: Evidence from China based on the three‐stage DEA‐Malmquist index model approach

AbstractContinuous improvement of technological innovation ability, adjustment of the development strategy, and enhancement of operational performance are of great theoretical and practical significance for logistics enterprises. This paper aims to analyze and evaluate the innovation efficiency of the logistics industry. The study utilizes the static three‐stage DEA model and the dynamic Malmquist index model, considering a total of 12 indicators related to innovation input, output, and environmental variables. A dataset of 2940 entries from 49 listed logistics enterprises from 2017 to 2021 was calculated. The analysis provides insights into the innovation efficiency of logistics enterprises from a static perspective and the innovation total factor productivity from a dynamic perspective and decomposition terms. Based on the analysis of environmental variables by the SFA model, it was found that DEA inefficiency is the combined result of environmental factors and management inefficiency. Environmental variables have both positive and negative effects on innovation. The improvement of the economic development level will lead to excess R&D investment. Increased government simple fund subsidies are not conducive to the efficient allocation of innovation resources within enterprises. The expansion of enterprise scale will increase R&D personnel and investment in fixed assets. A thriving technology market can encourage enterprises to improve their own conversion rate of scientific and technological output and give full play to their innovation ability. The dynamic Malmquist model analysis reveals a recution in the overall innovation efficiency of listed logistics enterprises over 5 years. The changes in total factor productivity and technological progress efficiency of all listed logistics enterprises are synchronized, with most enterprises exhibiting higher technological progress efficiency compared to comprehensive technical efficiency. The total factor productivity of logistics enterprise innovation is mainly affected by comprehensive technical efficiency.

Muddying the unexplored post-industrial waters: Biodiversity and conservation potential of freshwater habitats in fly ash sedimentation lagoons

Deposits of fly ash and other coal combustion wastes are common remnants of the energy industry. Despite their environmental risks from heavy metals and trace elements, they have been revealed as refuges for threatened terrestrial biodiversity. Surprisingly, freshwater biodiversity of fly ash sedimentation lagoons remains unknown despite such lack of knowledge strongly limits the efficient restoration of fly ash deposits. We bring the first comprehensive survey of freshwater biodiversity, including nekton, benthos, zooplankton, phytoplankton, and macrophytes, in fly ash lagoons across industrial regions of the Czech Republic. To assess their conservation potential, we compared their biodiversity with abandoned post-mining ponds, the known strongholds of endangered aquatic species in the region with a shortage of natural ponds. Of 28 recorded threatened species, 15 occurred in the studied fly ash lagoons, some of which were less abundant or even absent in the post-mining ponds. These are often species of nutrient-poor, fishless waters with rich vegetation, although some are specialised extremophiles. Species richness and conservation value of most groups in the fly ash lagoons did not significantly differ from the post-mining ponds, except for species richness of benthos, zooplankton, and macrophytes, which were slightly lower in the fly ash lagoons. Although the concentrations of some heavy metals (mainly Se, V, and As) were significantly higher in the fly ash lagoons, they did not significantly affect species richness or conservation value of the local communities. The differences in species composition therefore does not seem to be caused by water chemistry. Altogether, we have shown that fly ash lagoons are refuges for threatened aquatic species, and we thus suggest maintaining water bodies during site restoration after the cessation of fly ash deposition. Based on our analyses of environmental variables, we discuss suitable restoration practices that efficiently combine biodiversity protection and environmental risk reduction.

Improvement Proposal based on the Optimization of Environmental Variables for the Production of an Aquaponic System (Greenhouse) at the Campus "Los Robles", Fundación Universitaria de Popayán, Colombia

Abstract: The research focuses on the analysis of environmental variables and the operation of a greenhouse used for the production of fish and plants under aquaponic technology. It is important to mention the existence of studies on these techniques, although they do not represent and provide the totality of knowledge on the processes that occur in them, from their design and materiality. This work intends to make a contribution to sustainable production in aquaponic systems (greenhouse), studying the variables that most affect the development of plants and fish. The research was carried out in the aquaponic prototype of the "Los Robles" campus of the Fundación Universitaria de Popayán, Colombia. Initially, the effect of the physical and environmental parameters of the greenhouse was analyzed, such as design, production area, structure, climate and environment, which are variables that influence the productive performance of the greenhouses (fish and plants installed). With the results obtained from the analysis of environmental variables, improvements are proposed to optimize the production system. This proposal aims to contribute to food security and the social and productive reactivation of the communities in the region.

METHODS AND CHALLENGES IN TIMESERIES ANALYSIS OF VEGETATION IN THE GEOSPATIAL DOMAIN

Abstract. The increasing availability of remotely sensed data have offered unprecedented possibilities for monitoring and analysis of environmental variables, including boosting recent studies in the field of ecosystem resilience relying on indicators derived from timeseries analysis, such as the temporal autocorrelation of vegetation indices. A forest ecosystem with decreased resilience will be more susceptible to external drivers and their change and could shift into an alternative system configuration by crossing a tipping point. Nevertheless, remote sensing data quantifying vegetation and forests properties inherently carry information related to the climate as well, which has to be accounted for before performing any modelling exercise. In this paper, we aim to present the general workflow and the challenges encountered in processing and analysing the historical, high-frequency and high-resolution timeseries of vegetation and climatic data. The final aim is training a machine learning model (Random Forest) in order to model and explore the performance and importance of a set of climatic and environmental metrics in predicting an indicator of the resilience of forests. In this case, the resilience of forests is quantified through the temporal autocorrelation (TAC) of the kernel NDVI (kNDVI). Climatic and environmental predictors include 2-meter air temperature, total precipitation, vapour pressure deficit, surface solar radiation, forest cover and soil organic carbon content. Results show a good performance of the Random Forest model and the ranking in the importance of the predicting variables captured in terms of background climate and climate variability. This application allows to separate and identify the main drivers of the temporal autocorrelation of kNDVI.

Eutrophication levels increase sulfur biotransformation and emissions from sediments of Lake Taihu

Eutrophication can stimulate the emissions of volatile sulfur compounds (VSCs) accompanied by variations in environmental variables in lakes. However, the effects of eutrophication on VSC emissions from lake sediments as well as the underlying mechanisms remain unclear. In this study, depth gradient sediments at different eutrophication levels and seasons were collected from Lake Taihu to investigate the response of sulfur biotransformation in the sediments to eutrophication based on the analysis of environmental variables, microbial activity, abundance and community structure. H2S and CS2 were the main VSCs produced from the lake sediments, with the production rates of 2.3–7.9 and 1.2–3.9 ng g−1 h−1 in August, respectively, which were higher than those in March, mainly due to the increasing activity and abundance of sulfate-reducing bacteria (SRB) at high temperatures. The VSC production rates from the sediments increased with lake eutrophication level. Higher VSC production rates were detected in surface sediments in eutrophic regions but in deep sediments in oligotrophic regions. Sulfuricurvum, Thiobacillus and Sulfuricella were the main sulfur-oxidizing bacteria (SOB) in the sediments, while Desulfatiglans and Desulfobacca were the predominant SRB. Organic matter, Fe3+, NO3−-N and total sulfur had significant influences on the microbial communities in the sediments. Partial least squares path modelling showed that the trophic level index could stimulate VSC emissions from lake sediments by influencing the activities and abundances of SOB and SRB. These findings indicated that sediments contributed substantially to VSC emissions from eutrophic lakes, especially surface sediments, and sediment dredging might be an effective way to mitigate VSC emissions from eutrophic lakes.

Multi-omics eco-surveillance of complex legacy contamination with a locally adapted estuarine invertebrate

Complex legacy contamination from human use is a major issue for estuaries globally. In particular, contamination of water and sediments with bioavailable metals/metalloids, in addition to other industrial contaminants, such as hydrocarbons. Yet, understanding of complex toxicity and local adaptation in field exposed, non-model, invertebrate communities is limited. Herein, we apply multi-omics (metabolomics, lipidomics, proteomics) coupled to traditional sediment quality analyses, to better characterise molecular and cellular responses necessary for application to monitoring, as an eco-surveillance tool. Using these approaches, we characterise functional phenotypes of a sediment associated invertebrate (sipunculid), from an estuary exposed to complex legacy contamination (metals: Zn, Hg, Cd, Pb, Cu, As; and polycyclic aromatic hydrocarbons, PAHs). We sampled individuals at a range of exposure sites, highly (NTB5), moderately (NTB13), and lesser-influenced reference sites. Size differences were observed in sampled individuals between sites, with smaller individuals collected from NTB13. Analysis of environmental variables that correlated with change in the metabolite data revealed that the metabolism of smaller individuals at medium exposure NTB13 was highly differentiated by sediment concentrations of Hg, despite higher concentrations at more exposed NTB5. Functional phenotypes of these smaller individuals were characterised by sulphur and aromatic amino acid metabolism, increases in oxidised intermediates, upregulation of protein responses to oxidative stress, and melanin synthesis, and saturation of membrane and storage of lipids; in addition to the metabolism of naphthalene (PAH). Such widespread change was not observed in the metabolite and lipid profiles of larger individuals at high exposure NTB5, suggesting possible differences in effects between sites may also be associated with size (developmental stage, or age) and/or PAH exposure. This study serves to further understanding of differing modes of toxicity and local adaptation to multiple contaminants, and drivers of functional change in a complex estuary environment.

The terroir of the finch: How spatial and temporal variation shapes phenotypic traits in DARWIN'S finches.

The term terroir is used in viticulture to emphasize how the biotic and abiotic characteristics of a local site influence grape physiology and thus the properties of wine. In ecology and evolution, such terroir (i.e., the effect of space or “site”) is expected to play an important role in shaping phenotypic traits. Just how important is the pure spatial effect of terroir (e.g., differences between sites that persist across years) in comparison to temporal variation (e.g., differences between years that persist across sites), and the interaction between space and time (e.g., differences between sites change across years)? We answer this question by analyzing beak and body traits of 4388 medium ground finches (Geospiza fortis) collected across 10 years at three locations in Galápagos. Analyses of variance indicated that phenotypic variation was mostly explained by site for beak size (η 2 = 0.42) and body size (η 2 = 0.43), with a smaller contribution for beak shape (η 2 = 0.05) and body shape (η 2 = 0.12), but still higher compared to year and site‐by‐year effects. As such, the effect of terroir seems to be very strong in Darwin's finches, notwithstanding the oft‐emphasized interannual variation. However, these results changed dramatically when we excluded data from Daphne Major, indicating that the strong effect of terroir was mostly driven by that particular population. These phenotypic results were largely paralleled in analyses of environmental variables (rainfall and vegetation indices) expected to shape terroir in this system. These findings affirm the evolutionary importance of terroir, while also revealing its dependence on other factors, such as geographical isolation.

Participatory mapping identifies risk areas and environmental predictors of endemic anthrax in rural Africa

Disease mapping reveals geographical variability in incidence, which can help to prioritise control efforts. However, in areas where this is most needed, resources to generate the required data are often lacking. Participatory mapping, which makes use of indigenous knowledge, is a potential approach to identify risk areas for endemic diseases in low- and middle-income countries. Here we combine this method with Geographical Information System-based analyses of environmental variables as a novel approach to study endemic anthrax, caused by the spore-forming bacterium Bacillus anthracis, in rural Africa. Our aims were to: (1) identify high-risk anthrax areas using community knowledge; (2) enhance our understanding of the environmental characteristics associated with these areas; and (3) make spatial predictions of anthrax risk. Community members from the Ngorongoro Conservation Area (NCA), northern Tanzania, where anthrax is highly prevalent in both animals and humans, were asked to draw areas they perceived to pose anthrax risks to their livestock on geo-referenced maps. After digitisation, random points were generated within and outside the defined areas to represent high- and low-risk areas, respectively. Regression analyses were used to identify environmental variables that may predict anthrax risk. Results were combined to predict how the probability of being a high-risk area for anthrax varies across space. Participatory mapping identified fourteen discrete high-risk areas ranging from 0.2 to 212.9 km2 in size and occupying 8.4% of the NCA. Areas that pose a high risk of anthrax were positively associated with factors that increase contact with Bacillus anthracis spores rather than those associated with the pathogen’s survival: close proximity to inland water bodies, where wildlife and livestock congregate, and low organic carbon content, which may indicate an increased likelihood of animals grazing close to soil surface and ingesting spores. Predicted high-risk areas were located in the centre of the NCA, which is likely to be encountered by most herds during movements in search for resources. We demonstrate that participatory mapping combined with spatial analyses can provide novel insights into the geography of disease risk. This approach can be used to prioritise areas for control in low-resource settings, especially for diseases with environmental transmission.

Evaluation of Marginal Land Potential and Analysis of Environmental Variables of Jerusalem Artichoke in Shaanxi Province, China

Based on the maximum entropy modeling (Maxent) and ArcGIS tool, this study assessed the potential of marginal land and analyzed the impact of environmental variables for Jerusalem artichoke (Helianthus tuberosus L.) in Shaanxi Province, China. The results showed that the dominant land type used for the growth of Jerusalem artichoke was moderately dense grassland. Additionally, significant environmental variables of Jerusalem artichoke and their suitable range in Shaanxi Province were average slope (SLP, 0–5°C), average soil depth (DPT, 1.50–1.60 m), max temperature of the warmest month (Bio5, 30–31°C), annual mean temperature (Bio1, 16.5–18.0°C), precipitation of the wettest quarter (Bio16, 0.01–0.02 m), July solar radiation (SR7, 1.66–1.67 × 107 W/m2), precipitation seasonality (Bio15, 50–60%), precipitation of the driest quarter (Bio17, 0–0.005 m), and isothermality (Bio3, 265–275). Furthermore, the suitable area was mainly distributed in southern (mainly Hanzhong, Ankang, and Shangluo) and northern (mainly Yan’an and Yulin) parts of Shaanxi Province, covering around 8.81 × 1010 m2 and accounting for 42.8% of the total area of the Shaanxi Province. This study can provide a reference for the rational planting of Jerusalem artichoke in Shaanxi Province.

Analysis of Environmental Variables and Carbon Input on Soil Microbiome, Metabolome and Disease Control Efficacy in Strawberry Attributable to Anaerobic Soil Disinfestation.

Charcoal rot and Fusarium wilt, caused by Macrophomina phaseolina and Fusarium oxysporum f. sp. fragariae, respectively, are major soil-borne diseases of strawberry that have caused significant crop losses in California. Anaerobic soil disinfestation has been studied as an industry-level option to replace soil fumigants to manage these serious diseases. Studies were conducted to discern whether Gramineae carbon input type, incubation temperature, or incubation duration influences the efficacy of this disease control tactic. In experiments conducted using ‘low rate’ amendment applications at moderate day/night temperatures (24/18 °C), and carbon inputs (orchard grass, wheat, and rice bran) induced an initial proliferation and subsequent decline in soil density of the Fusarium wilt pathogen. This trend coincided with the onset of anaerobic conditions and a corresponding generation of various anti-fungal compounds, including volatile organic acids, hydrocarbons, and sulfur compounds. Generation of these metabolites was associated with increases in populations of Clostridium spp. Overall, carbon input and incubation temperature, but not incubation duration, significantly influenced disease suppression. All Gramineae carbon inputs altered the soil microbiome and metabolome in a similar fashion, though the timing and maximum yield of specific metabolites varied with input type. Fusarium wilt and charcoal rot suppression were superior when anaerobic soil disinfestation was conducted using standard amendment rates of 20 t ha−1 at elevated temperatures combined with a 3-week incubation period. Findings indicate that anaerobic soil disinfestation can be further optimized by modulating carbon source and incubation temperature, allowing the maximum generation of antifungal toxic volatile compounds. Outcomes also indicate that carbon input and environmental variables may influence treatment efficacy in a target pathogen-dependent manner which will require pathogen-specific optimization of treatment protocols.

Ecological Diversity within Rear-Edge: A Case Study from Mediterranean Quercus pyrenaica Willd.

Understanding the ecology of populations located in the rear edge of their distribution is key to assessing the response of the species to changing environmental conditions. Here, we focus on rear-edge populations of Quercus pyrenaica in Sierra Nevada (southern Iberian Peninsula) to analyze their ecological and floristic diversity. We perform multivariate analyses using high-resolution environmental information and forest inventories to determine how environmental variables differ among oak populations, and to identify population groups based on environmental and floristic composition. We find that water availability is a key variable in explaining the distribution of Q. pyrenaica and the floristic diversity of their accompanying communities within its rear edge. Three cluster of oak populations were identified based on environmental variables. We found differences among these clusters regarding plant diversity, but not for forest attributes. A remarkable match between the populations clustering derived from analysis of environmental variables and the ordination of the populations according to species composition was found. The diversity of ecological behaviors for Q. pyrenaica populations in this rear edge are consistent with the high genetic diversity shown by populations of this oak in the Sierra Nevada. The identification of differences between oak populations within the rear-edge with respect to environmental variables can aid with planning the forest management and restoration actions, particularly considering the importance of some environmental factors in key ecological aspects.

Análisis multicriterio para la localización de centrales fotovoltaicas de gran escala

La matriz energética del Ecuador supera el 75% de energía renovable, sin embargo, la fuente principal es la energía hidroeléctrica. Como primer paso hacia la obtención de una matriz más amigable con el ambiente y más diversa es fundamental identificar zonas con potencial para la instalación de energías renovables no convencionales, los Sistemas de Información Geográfico (SIG) son de gran ayuda para identificar zonas con este potencial. En este estudio se identifican los posibles sitios para la implantación de centrales solares fotovoltaicas (CSF) en la Provincia del Azuay mediante los SIG y la Evaluación Multicriterio (EM). Para valorar la importancia de los criterios se empleó el Método Analítico Jerárquico (AHP). Para la obtención de un modelo de capacidad de acogida se integró el modelo de aptitud en el que se analizaron criterios económicos y técnicos; y un modelo de impacto que analizo variables ambientales. Al integrar los modelos esta metodología permitirá la identificación de zonas para el emplazamiento de estaciones que permitan el monitoreo de los recursos y el análisis del comportamiento previo a la implementación de las CSF. Una vez ejecutada la metodología propuesta se obtiene como resultado dos posibles sitios con características medias para el emplazamiento de CSF. Como conclusión en base a los indicadores analizados el Azuay no cuenta con una zona potencialmente adecuada para la instalación de esta tecnología.

The potential distribution and disappearing of Yunnan snub-nosed monkey: Influences of habitat fragmentation

Analysisof environmental variables and organism occurrence records offers insight that can be used to predict potential distribution areas and habitat fragmentation. For large landscapes, modeling is the most convenient and effective way to conduct habitat research. Two species distribution models, BIOMOD2 and FRAGSTATS 4.2, were given data on environmental variables and organism occurrence records as input and used to predict the potential suitable habitat and habitat fragmentation for the Yunnan snub-nosed monkey (Rhinopithecus bieti). Our results estimated the total area of potentially suitable habitat for R. bieti as 7412.82 km2, but only 4164.58 km2 was found to be inhabited by R. bieti. We found that the main land cover type in the potential suitable distribution area of R. bieti was evergreen needle-leaf forest (6153.95 km2, 83.02%). Comparison of inhabited and suitable but uninhabited habitats showed that areas actually inhabited by R. bieti had a lower patch density (PD) and higher largest patch index (LPI) than uninhabited habitats only in evergreen needle-leaf forest. The potential suitable habitats of R. bieti has increased significantly, but the actual distribution has shrunk from 1997 to 2017. Although the government has made great progress in protecting R. bieti, logging that took place before the regulations and the boundary effect of roads and rivers resulted in the local extinction of R. bieti in some potentially suitable areas. In view of this, we propose to establish a national park for Yunnan snub-nosed monkeys. We also suggest protecting the potentially suitable but currently empty habitats for later release of R. bieti. Successfully reintroducing R. bieti into areas where it formerly lived will require continual and careful habitat monitoring.

Multivariate spatial patterns analysis of environmental variables and benthic metrics in five California waterbodies

Multivariate spatial patterns of 38 environmental variables (habitat metrics, metals, pyrethroids and sediment characteristics) and 14 benthic metrics were determined from over a decade of sampling in five California waterbodies. Canonical discriminant analyses produced very highly significant separations of the five watersheds based on environmental variables. The discriminant analyses based on benthic metrics also produced highly significant separations, although confidence ellipses were not quite as well separated as the environmental variables. Separation of creeks made ecological sense as Pleasant Grove Creek (PGC), which appeared to have greater habitat quality also had benthic metrics indicative of less stressed benthic communities, while the Santa Maria River watershed (SM) appeared to have lower habitat quality and more toxicants in the sediments also appeared to have benthic communities indicative of stress-tolerant taxa. The benthic community health of the other three creeks (Arcade Creek [ARC], Kirker Creek [KC] and Salinas Streams [SAL]) were considered intermediate in apparent stress between PGC and SM. Overall, benthic communities were somewhat more similar between creeks than were the environmental conditions. Benthic communities have greater overlap in characteristics than would be expected from environmental conditions, perhaps due to a greater resilience since they are generally dominated by tolerant benthic taxa.

Long-term variations in macrobenthic community diversity (species number) in the Chokchon macrotidal flat, Incheon, Korea

We performed a time-series analysis of environmental variables and biological parameters to understand temporal variations in the macrobenthic community in the Chokchon macrotidal flats, Incheon, Korea. Bimonthly sampling of macrobenthos and sediments was conducted from May 1989 through November 2001. A decomposition method composed of seasonality, trends and cyclical variation was employed in this study. We focused on trends of the selected variables and assumed that those with positive or negative trends caused changes in biological parameters. Most variables showed strong seasonality (≥ 95% of the total variance). Significant positive trends (p < 0.0001) were observed in sea water temperature and sediment ignition loss. Macrobenthic biomass and species number also showed significant positive trends (p < 0.0001). Biomass indicated that the study area underwent eutrophication since the mid 1990s. A notable increase in species number occurred throughout the study period. The flattened temperature trend after 1994 and intensified eutrophication after the mid 1990s indicated that the species increase in the former period was in response to increasing temperature, while that in the latter period was caused by eutrophication. Although our study suggested an increasing trend in diversity, it is important to check for unexpected changes and establish monitoring programs to provide early warnings, especially in lower latitudes.

Controls of picophytoplankton abundance and composition in a highly dynamic marine system, the Northern Alboran Sea (Western Mediterranean)

The Alboran Sea is a highly dynamic basin which exhibits a high spatio-temporal variability of hydrographic structures (e.g. fronts, gyres, coastal upwellings). This work compares the abundance and composition of picophytoplankton observed across the northern Alboran Sea among eleven cruises between 2008 and 2012 using flow cytometry. We evaluate the seasonal and longitudinal variability of picophytoplankton on the basis of the circulation regimes at a regional scale and explore the presence of cyanobacteria ecotypes in the basin. The maximal abundances obtained for Prochlorococcus, Synechococcus and picoeukaryotes (12.7×104, 13.9×104 and 8.6×104cellsmL−1 respectively) were consistent with those reported for other adjacent marine areas. Seasonal changes in the abundance of the three picophytoplankton groups were highly significant although they did not match the patterns described for other coastal waters. Higher abundances of Prochlorococcus were obtained in autumn-winter while Synechococcus and picoeukaryotes exhibited a different seasonal abundance pattern depending on the sector (e.g. Synechococcus showed higher abundance in summer in the west sector and during winter in the eastern study area). Additionally, conspicuous longitudinal gradients were observed for Prochlorococcus and Synechococcus, with Prochlorococcus decreasing from west to east and Synechococcus following the opposite pattern. The analysis of environmental variables (i.e. temperature, salinity and inorganic nutrients) and cell abundances indicates that Prochlorococcus preferred high salinity and nitrate to phosphate ratio. On the contrary, temperature did not seem to play a role in Prochlorococcus distribution as it was numerically important during the whole seasonal cycle. Variability in Synechococcus abundance could not be explained by changes in any environmental variable suggesting that different ecotypes were sampled during the surveys. In particular, our data would indicate the presence of at least two ecotypes of Synechococcus: a summer ecotype widely distributed in the whole Alboran Sea and a winter ecotype adapted to lower temperature and higher nutrient concentration whose growth is favoured in the eastern sector.

Assassin bugs of the subfamily Diaspidiinae (Heteroptera: Reduviidae): distribution and potential ecological niches

AbstractThe prediction and definition of the conditions for the potentially suitable ecological niche of the subfamily Diaspidiinae was the main goal of this study. Our research was based on 283 specimens of all known species of assassin bugs belonging to the subfamily Diaspidiinae stored in European museum collections and a set of 21 environmental variables in the form of a 1 × 1 km grid covering Africa and Madagascar. Based on occurrence localities, as well as a digital elevation model and layer of the tree cover‐continuous fields, information about the distribution of each species is given. Using Maxent software, potentially useful ecological niches were modeled, which allowed for the creation of a map of the potential distribution of the members of this subfamily and for determining their climatic preferences. A jackknife test showed that annual precipitation, annual temperature range and tree cover‐continuous fields were the most important environmental variables affecting the distribution of the subfamily Diaspidiinae. An analysis of climatic preferences suggested that the representatives of the subfamily were linked mainly to the tropical climate. An analysis of environmental variables also showed that the subfamily preferred areas with herbaceous vegetation and some trees, and this preference is probably caused by the food preferences of their prey. On the basis of the museum data on the species occurrence, as well as ecological niche modeling methods, we provided new and valuable information on potentially suitable habitat and the possible range of distribution of the subfamily Diaspidiinae along with its climatic preferences.

Analysis of environmental variables on population dynamic change of Haliscomenobacter hydrossis, the bulking causative filament in Macau wastewater treatment plant

Macau Peninsula wastewater treatment plant (WWTP) is experiencing filamentous bulking in recent years, which is caused by overgrowth of filamentous bacteria of Haliscomenobacter hydrossis, thus interfering the settling of activated sludge. Previous studies using molecular techniques have been widely used for identifying and quantifying the dominant filaments. However, the mechanisms caused by various environmental variables have not yet been completely understood to form the deterministic cause–effect relationship. In this study, principal component analysis (PCA) and generalized linear model (GLM) were used to analyze various environmental variables on the population dynamic changes of H. hydrossis identified and quantified as the dominant bulking causative filament using quantitative real-time PCR (qPCR). Our results showed that the qPCR was successful for identifying and quantifying the H. hydrossis. Correlation analysis indicated that ammonia nitrogen sources and sludge volume index (SVI) have strongly positive correlations with H. hydrossis. PCA can explain 75.21% of the variance from the total data in PC1-PC4 and GLM revealed a unimodal relationship between the overall H. hydrossis gene copies number and three environmental variables. Besides, the quadratic increases in the number of H. hydrossis copies were observed with the increasing gradient of SVI, TN, and NH3-N, suggesting that H. hydrossis played an important role in filamentous bulking of the WWTP.

Model of potential distribution of Platymeris rhadamanthus Gerstaecker, 1873 with redescription of species

The redescription of Platymeris rhadamanthus Gerstaecker, 1873 as well as the designation of lectotype and paralectotype, plus the prediction of the potentially suitable habitat was the main goal of this study. Our research were based on 262 specimens of museum collections of P. rhadamanthus species and a set of 23 environmental predictor variables, all recorded in a 1x1 km grid covering Africa. Ecological niche modelling was performed using the MAXENT analyses to produce predictive potential distribution maps for this species and its colour forms separately. The results suggested the most suitable areas of distribution of P. rhadamanthus, both for species as a whole and also for the colour forms. A jackknife test showed that the precipitation of coldest quarter and herbaceous vegetation were the most important environmental variables affecting the distribution of P. rhadamanthus. After analyzing the climatic preferences, this species seems to be related mainly to the tropical savanna climate, subtropical highland variety of the oceanic climate and humid subtropical climate. An analysis of environmental variables also showed that this species prefers areas with herbaceous vegetation, with a small participation of trees, which is probably caused by food preferences of its victims. P. rhadamanthus so far was only known that it occurs in widely understood tropical Africa. On the base of the museum data on the occurrence of the species and ecological niche modelling methods we provided new and valuable information of the potentially suitable habitat, the possible range of distribution of the species and its climatic preferences.