Afforestation enhances glomalin-related soil protein content but decreases its contribution to soil organic carbon in a subtropical karst area.

Afforestation on degraded croplands has been proposed as an effective measure to promote ecosystem functions including soil organic carbon (SOC) sequestration. Glomalin-related soil protein (GRSP) plays a crucial role in promoting the accumulation and stability of SOC. Nevertheless, mechanisms underlying the effects of afforestation on GRSP accumulation have not been well elucidated. In the present study, 14 pairs of maize fields and plantation forests were selected using a paired-site approach in a karst region of southwest China. By measuring soil GRSP and a variety of soil biotic and abiotic variables, the pattern of and controls on GRSP accumulation in response to afforestation were explored. The average content of total GRSP (T-GRSP) and its contribution to SOC in the maize field were 5.22 ± 0.29 mg g-1 and 42.33 ± 2.25%, and those in the plantation forest were 6.59 ± 0.32 mg g-1 and 25.77 ± 1.17%, respectively. T-GRSP content was increased by 26.4% on average, but its contribution to SOC was decreased by 39.1% following afforestation. T-GRSP content decreased as soil depth increased regardless of afforestation or not. Afforestation increased T-GRSP indirectly via its positive effects on arbuscular mycorrhizal fungi biomass, which was stimulated by afforestation through elevating fine root biomass or increasing the availability of labile C and N. The suppressed contribution of T-GRSP to SOC following afforestation was due to the relatively higher increase in other SOC components than T-GRSP and the significant increase of soil C:N ratio. Our study reveals the mechanisms underlying the effects of afforestation on T-GRSP accumulation, and is conducive to improving the mechanistic understanding of microbial control on SOC sequestration following afforestation.

Preliminary Study on Hourly Dynamics of a Ground-Dwelling Invertebrate Community in a Farmland Vineyard.

We evaluated the hourly dynamics of ground-dwelling invertebrate communities in farmland using infrared camera traps between August and September 2022. No significant variations within 24 h nor between any two time points of each day were observed in the taxonomic richness and abundance of the entire community. However, the periods from 4:00 to 7:00 and 13:00 to 20:00 showed relatively high taxonomic richness, while those from 2:00 to 6:00 and 16:00 to 21:00 showed relatively high abundance. Millipede abundance varied significantly in a 24 h period, with higher abundance from 3:00 to 4:00 and 1:00 to 2:00. Additionally, slug, beetle, and grasshopper abundances were significantly higher from 22:00 to 23:00, 17:00 to 18:00, and 23:00 to 24:00, respectively. The abundance of other taxa did not show significant variations between any two time points of a day. Predominant generalist predators showed positive correlation in their activity times. These results suggest that significant variations within each 24 h period are uncommon at either community or taxa (except for millipedes) levels in farmland ground-dwelling invertebrates. Further, while most taxa had significantly preferred active hours, the total community did not. Therefore, hourly dynamics should be considered to understand biodiversity maintenance.

Environmental Adaptability and Energy Investment Strategy of Different Cunninghamia lanceolata Clones Based on Leaf Calorific Value and Construction Cost Characteristics.

The calorific value and construction cost of leaves reflect the utilization strategy of plants for environmental resources. Their genetic characteristics and leaf functional traits as well as climate change affect the calorific values. This study explores the differences in energy investment strategies and the response characteristics of energy utilization in leaves to climate change among nine clones of Chinese fir (Cunninghamia lanceolata). Considering the objectives, the differences in the energy utilization strategies were analyzed by determining the leaf nutrients, specific leaf area, and leaf calorific value and by calculating the construction cost. The results showed a significant difference in the ash-free calorific value and construction cost of leaves among different Chinese fir clones (p < 0.05). There were also significant differences in leaf carbon (C) content, leaf nitrogen (N) content, specific leaf area, and ash content. The correlation analysis showed that leaves' ash-free calorific value and construction cost were positively correlated with the C content. Principal component analysis (PCA) showed that P2 is inclined to the "fast investment return" energy investment strategy, while L27 is inclined to the "slow investment return" energy investment strategy. Redundancy analysis (RDA) indicates that the monthly average temperature strongly correlates positively with leaf construction cost, N content, and specific leaf area. The monthly average precipitation positively impacts the ash-free calorific value and construction cost of leaves. In conclusion, there are obvious differences in energy investment strategies among different Chinese fir clones. When temperature and precipitation change, Chinese fir leaves can adjust their energy investment to adapt to environmental changes. In the future, attention should be paid to the impact of climate change-related aspects on the growth and development of Chinese fir plantations.

Surface phytolith and pollen assemblages of a low-latitude subtropical region in Southwest China and their implications for vegetation and climate.

Phytoliths, as a newly developing plant proxy, have broad application prospects in paleoclimate and paleoethnobotany. However, the shortage of studies regarding tropical-subtropical plants and topsoil phytoliths interferes with the research progress on primitive humanity's utilization of plant resources and paleoclimate in the region. This research focuses on the subtropical mountainous region with a monsoon climate of low latitudes in Southwest China to conduct phytolith morphology analysis of living plants and phytolith/pollen assemblages of topsoil to reveal the indicative significance of vegetation and climate. A total of 111 species from 50 families, including 73 species from 33 tree/shrub families, 31 species from 12 herb families and 7 species from 5 fern families, were collected for morphological characteristics analysis, as well as 19 topsoil specimens for phytolith and pollen assemblage analysis. The results suggest that phytoliths are mainly deposited in situ, with assemblages of topsoil corresponding well with plant types in the quadrat and being able to exhibit constructive species in small regions. In comparison, pollen assemblages of topsoil dominantly respond to regional vegetation due to their long-distance transportation and widespread presence, in addition to their characteristics that correspond to the vegetation in the quadrat. The topsoil phytolith assemblages are mainly based on the elongate-bulliform flabellate-square/rectangle-broadleaf-types (including spheroid echinate), and the vegetation types indicate the subtropical climate. In addition, phytolith assemblages of Poaceae are dominated by collapsed saddle-bulliform flabellate square/rectangle-elongate-point, reflecting warm and humid conditions. The pollen assemblages mainly consist of Pinus, Betula, Alnus, deciduous Quercus, Euphorbiaceae, Rhamnaceae and Polygonum, reflecting tropical-subtropical plant communities and indicating warm and humid conditions. Overall, phytolith and pollen assemblages have unique characteristics and are thus explicitly representative of the low-latitude subtropical monsoon climate.

A Molecular Systematics and Taxonomy Research on Trechispora (Hydnodontaceae, Trechisporales): Concentrating on Three New Trechispora Species from East Asia.

Trechispora are an important genus of wood-inhabiting fungi that have the ability to decompose rotten wood in the forest ecosystem. In this study, we reported three new species of Trechispora: T. murina, T. odontioidea, T. olivacea from a subtropical region of Yunnan Province, China. Species descriptions were based on a combination of morphological features and phylogenetic analyses of the ITS and LSU region of nuclear ribosomal DNA. Trechispora murina is characterized by the resupinate basidiomata, grandinioid hymenial surface with a greyish tint, monomitic hyphal system and ellipsoid, thick-walled, ornamented basidiospores; T. odontioidea has an odontioid hymenial surface with cylindrical to conical, blunt aculei and subglobose to globose, colorless, slightly thick-walled, ornamented basidiospores; T. olivacea has a farinaceous hymenial surface with olivaceous tint, basidia clavate and thick-walled, ornamented, broadly ellipsoid to globose basidiospores. Sequences of the ITS and nLSU rDNA markers of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony, and Bayesian inference methods. After a series of phylogenetic analyses, the 5.8S+nLSU dataset was constructed to test the phylogenetic relationship of Trechispora with other genera of Hydnodontaceae. The ITS dataset was used to evaluate the phylogenetic relationship of the three new species with other species of Trechispora. Using ITS phylogeny, the new species T. murina was retrieved as a sister to T. bambusicola with moderate supports; T. odontioidea formed a single lineage and then grouped with T. fimbriata and T. nivea; while T. olivacea formed a monophyletic lineage with T. farinacea, T. hondurensis, and T. mollis.

Soil Nitrogen Transformation Process Influenced by Litterfall Manipulation in Two Subtropical Forest Types.

Nitrogen (N) is often recognized as the primary limiting nutrient element for the growth and production of forests worldwide. Litterfall represents a significant pathway for returning nutrients from aboveground parts of trees to the soils and plays an essential role in N availability in different forest ecosystems. This study explores the N transformation processes under litterfall manipulation treatments in a Masson pine pure forest (MPPF), and Masson pine and Camphor tree mixed forest (MCMF) stands in subtropical southern China. The litterfall manipulation included litterfall addition (LA), litterfall removal (LR), and litterfall control (LC) treatments. The project aimed to examine how litterfall inputs affect the soil N process in different forest types in the study region. Results showed that soil ammonium N (NH4 +-N) and nitrate N (NO3 --N) content increased under LA treatment and decreased under LR treatment compared to LC treatment. LA treatment significantly increased soil total inorganic N (TIN) content by 41.86 and 22.19% in MPPF and MCMF, respectively. In contrast, LR treatment decreased the TIN content by 10 and 24% in MPPF and MCMF compared to LC treatment. Overall, the soil net ammonification, nitrification, and N mineralization rates were higher in MCMF than in MPPF; however, values in both forests were not significantly different. LA treatment significantly increased annual net ammonification, nitrification, and mineralization in both forest types (p < 0.05) compared to LC treatment. LR treatment significantly decreased the values (p < 0.05), except for ammonification, where LR treatment did not differ substantially compared to LC treatment. Our results suggested that changes in litterfall inputs would significantly alter soil N dynamics in studied forests of sub-tropical region. Moreover, mixed forest stands have higher nutrient returns due to mixed litter and higher decomposition compared to pure forest stands.

[Elevational Pattern and Control Factors of Soil Microbial Carbon Use Efficiency in the Daiyun Mountain].

Microbial carbon use efficiency (CUE) refers to the C transformation to microbial biomass from C uptake. The study of soil microbial CUE is very important for understanding the soil C cycle. Here, CUE, Cgrowth, and Crespiration were measured using the 18O-H2O-DNA labeling method at six elevational sites (980-1765 m) in Daiyun Mountain, a subtropical montane forest, to understand the variation characteristics and influencing mechanisms. The results showed that:CUE varied from 0.1 to 0.4 and increased linearly with elevation; CUE was positively correlated with Cgrowth, Crespiration, and qgrowth but negatively correlated with qCO2, indicating that CUE increased with elevation by increasing microbial growth and inhibiting respiration; and temperature was the first controlling factor for the elevation variation in microbial CUE in the subtropical forest ecosystem.

Environmental impacts, human health, and energy consumption of nitrogen management for maize production in subtropical region.

Over-application of fertilizers could not improve crop yield and agronomic efficiency, but result in increasing nitrogen (N) surplus and adverse effects on the ecosystem sustainability. Although some previous studies have addressed one or a few environmental aspects in crop production, an integrated assessment for the effects of N fertilizer on multiple environmental impacts, and the optional steps of normalization and weighting is required. A consecutive 2-year plot-based field experiment was conducted with five N fertilizer levels (0, 90, 180, 270, and 360 kg N ha-1) in maize production at three sites in Southwest China, to evaluate the environmental performance and sustainability through joint use of life cycle assessment (LCA) and energy consumption analysis. Results demonstrated that the optimal N rate (180 kg N ha-1) showed greater potential for maintaining high yield (achieved 86% of the yield potential) and reducing the global warming (- 31%), acidification (- 47%), eutrophication (- 44%) compared to farmers' practice, and energy depletion potentials, by reducing pollutants emission during the production and transportation of N fertilizer and Nr losses at farm stage. Optimal N treatment indirectly reduced the land use, life-cycle human toxicity, aquatic eco-toxicity, and terrestrial eco-toxicity potentials by improving grain yield and agronomic efficiency. In addition, the optimal N treatment reduced the energy consumption by enhancing the energy use efficiency (EUE) (+ 74%) and reducing non-renewable energy form (- 45%) than the farmer's practice. This study will provide comprehensive information for both scientists and farmers involved in maize production and N management in subtropical region.

Nitrogen leaching and grey water footprint affected by nitrogen fertilization rate in maize production: a case study of Southwest China.

BACKGROUND: Effective nitrogen (N) management measures are required to control environmental problems caused by N fertilizer use in intensive maize production systems. Soil N losses associated with high precipitation and over-fertilization in maize production can cause substantial environmental problems, whereas there is a lack of quantitative data and effective study countermeasures. A 2-year field study was conducted in the subtropical maize production system in Southwest China to quantify N leaching under varying N application rates of 0, 90, 180, 270 and 360 kg N ha-1  yr-1 . RESULTS: The results indicated that N leaching accounted for 16-38% of N fertilizer input. For farmer practice treatment (360 kg N ha-1  yr-1 ), N leaching loss was high at 110 kg N ha-1  yr-1 and accounted for 31% of the N applied. As an indicator of the ambient water quality pollution, the grey water footprint across all treatments ranged from 376 to 1092 m3 Mg-1 , with an average of 695 m3 Mg-1 . Reducing N rate to agronomically optimized treatment (180 kg N ha-1  yr-1 ) significantly decreased N leaching by 77%, and maintained high grain yield of 8.1 Mg ha-1 . The grey water footprint was reduced by 52-63% with N rates from 270 or 360 kg N ha-1  yr-1 to 180 kg N ha-1  yr-1 . CONCLUSION: Nitrogen surplus (applied N rate minus N uptake by maize) resulted in higher soil residual nitrate concentration and consequently high N leaching. High precipitation and low soil pH were the main ecological factors leading to high N leaching. © 2021 Society of Chemical Industry.

Effects of Overwintering on the Survival and Vector Competence of Aedes albopictus in the Urban Life Cycle of Dengue Virus in Guangzhou, China.

The Pearl River Delta, where Aedes albopictus (Ae. albopictus) is the only vector for dengue transmission, has exhibited one of the highest dengue burdens in southern China in recent decades. However, whether dengue virus (DENV) can overwinter in Ae. albopictus in the Pearl River Delta has not been determined to date. In this study, 300 field-derived Ae. albopictus mosquitoes from Guangzhou that were infected with the predominant endemic DENV-1 strain were investigated under simulated urban balcony environment from October 16, 2016, to June 16, 2017. The vertical transmission of DENV in the infected overwintering Ae. albopictus was analyzed. The DENV infected overwintering mosquitoes were evaluated for viral load at nine-time points using reverse transcription-quantitative PCR. The vector competence of the infected overwintering Ae. albopictus was also investigated by using suckling mice. Adult mosquitoes and larvae were found during the observation period. The vertical transmission of DENV-1 was documented. The DENV-1-positive rates between overwintering males and females had no difference. The proportion of DENV-1-positive overwintering mosquitoes decreased over time and had no difference beyond three months after the experiment. Overwintering mosquitoes can spread DENV-1 to hosts. No engorged mosquitoes at an ambient temperature below 15 °C were observed. The ratio of engorged mosquitoes was positively correlated with the ambient temperature ranging from 15 to 30 °C. Our results demonstrated that DENV can overwinter in Ae. albopictus in the Pearl River Delta, Ae. albopictus is the competent vector for DENV, and maintain autochthonous dengue outbreaks in the Pearl River Delta through vertical transmission.

Carbon footprint of maize production in tropical/subtropical region: a case study of Southwest China.

Maize production is critical in tropical/subtropical regions, especially in developing countries where maize is a staple food. However, its environmental costs remain unclear. Southwest China is a tropical/subtropical region with large-scale maize production in each of its sub-regions. In the present study, we used Southwest China as a case study to evaluate the greenhouse gas (GHG) emissions and carbon footprint (CF) of maize production during 1996-2015 using life cycle assessment to identify the driving factors behind the GHG emissions and CF and to propose potential mitigation strategies. The mean GHG emissions of maize production per year during 1996-2015 was 4132 kg CO2-eq·ha-1, and the CF during this period was 961 kg CO2-eq·Mg-1. The GHG emissions and CF in Southwest China were 2-4 times higher than those of other major maize-producing regions worldwide. The GHG emissions and CF were both significantly correlated with the N surplus. The N surplus was also linearly correlated with annual precipitation, annual temperature and growing degree days, but not significantly related with soil pH. Scenario testing showed that the CF of maize production in Southwest China could be reduced by 41%, i.e. to 437 kg CO2-eq·Mg-1, by farmers adopting a comprehensive strategy including recommended fertiliser application rates, innovative fertilisers, and crop management to decrease GHG emissions and achieve the yield potential in the region. Integrated soil and crop management is essential for sustainable maize production in tropical/subtropical regions with complex and changeable ecological conditions, especially in developing countries where maize is a staple food.

[Effects of warming on soil inorganic nitrogen in the young and mature Cunninghamia lanceolata plantations in humid subtropical region, China]. / å¢žæ¸©å¯¹æ¹¿æ¶¦äºšçƒ­å¸¦æ‰æœ¨å¹¼æž—å’Œæˆç†Ÿæž—åœŸå£¤æ— æœºæ°®çš„å½±å“.

Soil nitrogen cycling in forests may be accelerated or inhibited by global warming, with consequences on forest productivity. Such an impact will be more complicated with extending period of warming. We examined the effects of warming on soil inorganic nitrogen content in the young and mature Cunninghamia lanceolata plantations. Warming was simulated by means of soil cable warming, simulating a future climate change scenario of 4 ℃ warming. The results showed that after three years warming, both total soil inorganic nitrogen and ammonium contents in the young and mature plantations were significantly reduced. The sharp decline occurred in the young plantation, with soil ammonium content in 0-10, 10-20, 20-40, 40-60 cm soil layers decreased by 32.1%, 37.1%, 20.8% and 19.9%, respectively. Dissolved organic nitrogen was reduced and N2O emission was accelerated in the both plantations. The main reasons for the reduction of soil inorganic nitrogen concentration were lower input of organic nitrogen substrate and higher gaseous nitrogen loss. The decrease in soil organic nitrogen substrate and increase in gaseous nitrogen emissions in the young plantation were larger than those in the mature plantation, indicating that soils in the young plantation were more sensitive to increasing temperature. The 3-year warming decreased soil inorganic nitrogen contents in the two C. lanceolata plantations, which might negatively affect productivity of the C. lanceolata plantations in subtropic China.

Molecular diagnosis of Leishmania spp. in dogs of a subtropical locality of Argentina.

Leishmaniosis is a tropical and subtropical vector-borne disease caused by hemoparasites of the genus Leishmania. The disease can infect humans, as well as domestic and wildlife animals. Dogs are the main reservoir for L. infantum, the aetiological agent of visceral leishmaniosis (VL) in America, and a domestic source of L. braziliensis, the most widespread aetiological agent of American tegumentary leishmaniosis. Infected dogs can develop a clinical syndrome called canine leishmaniosis (CanL), which presents with skin lesions, mild fever; additionally hepatomegaly and splenomegaly can be observed, although asymptomatic infections are frequent. Direct microscopic observation of the parasite in bone marrow, blood, skin scrapings and conjunctival swab samples is the gold standard of diagnosis and is usually complemented with serological tests, and to a lesser extent, molecular detection of the parasite. In Argentina, leishmaniosis is an emerging disease, with a growing number of human and canine clinical cases since 2006. Our study was carried out in Mercedes, a town located in the subtropical north-eastern area of Argentina, where dogs with positive parasitological test results for Leishmania spp. must be euthanized according to local regulations. We evaluated the presence of Leishmania spp. DNA in the blood of dogs (n = 166) from urban and peri-urban zones. Genomic DNA was extracted from whole blood using Chelex 100 resin and a conserved 116 bp region of the kinetoplastid DNA was amplified by conventional PCR. Clinical signs, age and gender were recorded. Our results showed that 120 out of 166 surveyed dogs (72%) were positive for Leishmania spp. DNA of which only seven were positive by parasitological and serological tests. No significant correlation between positive cases and gender or age groups was found. This report shows the high prevalence of this disease in Argentina and contributes to improve public health policy with regard to diagnosis, prevention and treatment of infected dogs.

[Relationship of plant abundance, air temperature and humidity with negative ions based on control experiment]. / åŸºäºŽæŽ§åˆ¶è¯•éªŒçš„æ¤æ ªæ•°é‡åŠç©ºæ°”æ¸©æ¹¿åº¦ä¸Žè´Ÿç¦»å­çš„å ³ç³».

Previous studies on negative air ion (NAI), an important index for evaluating atmospheric quality, has been focused on field observation, and less on NAI under controlled condition. In this study, the NAI concentrations of different individual abundance of Liquidambar formosana and Taxus wallichiana were continuously monitored under the same climatic conditions in Hushan Experimental Base of Qianjiangyuan Forest Ecosystem Research Station, Zhejiang Province from September to October 2018. Changes of NAI concentration were monitored under different levels of air temperature and relative humidity to explore the effects of forest vegetation and meteorological factors on NAI. The results showed that both species significantly increased the NAI concentration. Plant abundance was positively correlated with the NAI concentration, and the relationship between them fitted the quadratic function with the plant abundance ranging from 0 to 50. The fitting equations for L. formosana and T. wallichiana were as follows: y=-0.0484x2+4.7005x+345.7 (R2=0.62), y=-0.0207x2+1.9189x+365.91 (R2=0.34). There was a significant positive correlation between NAI concentration and air temperature in the range of 5-30 ℃ with a fitting equation of y=0.4139x2-9.2229x+89.919 (R2=0.92). The NAI concentration and the relative humidity of air in the range of 56%-87% were positively correlated with a fitting equation of y=3.6508e0.0526x(R2=0.94).

The variation of vegetation greenness and underlying mechanisms in Guangdong province of China during 2001-2013 based on MODIS data.

This study explored the spatiotemporal variation of vegetation greenness and the mechanisms underlying this variation in the subtropical region of Guangdong in China during 2001-2013 to obtain a better understanding of vegetation response to climate and land use/cover changes in warm-humid regions. Satellite-based vegetation indices, land use/cover data and observed weather records during 2001-2013 were used. Univariate and multivariate linear regressions were conducted to quantify the trends and variations in vegetation greenness and the relationships with climate and land use/cover changes. The results indicated that the annual mean greenness trended upward significantly in eastern and western Guangdong and downward significantly in northern Guangdong. The patterns of significant positive or negative relationships between vegetation greenness and climatic factors were observed at the sub-regional scale. In addition, our results showed that (i) vegetation greenness in Guangdong was more sensitive to changes in temperature than in precipitation, (ii) spring temperature had an important time-lag effect on seasonal mean greenness in the following summer and autumn, and (iii) winter greenness depended largely on vegetation growth in the previous autumn. Furthermore, the conversion of grasslands and croplands to evergreen forests resulting from afforestation increased the vegetation greenness in eastern and western Guangdong. Overall, our results suggest that afforestation plays a dominant role in increasing vegetation cover/greenness in Guangdong whereas the effects of land use/cover change on vegetation growth are subject to climatic conditions. Thus, a better understanding of terrestrial vegetation dynamics requires considering both climate and land use/cover changes.

Isolation and identification of Acanthamoeba from pond water of parks in a tropical and subtropical region in the Middle East, and its relation with physicochemical parameters.

BACKGROUND: Free-living amoeba (FLA) are wide-spread protozoa that are found in different environmental sources including water, soil, dust, hospital units and ventilation areas. These amoebas can act as opportunistic or non-opportunistic pathogens. Among FLAs, some genera such as Acanthamoeba are important because of their potential pathogenic ability in humans. The purpose of this study is to identify of Acanthamoeba isolated from pond water of parks in a tropical and subtropical region in the Middle East, and its relation with physicochemical parameters.From August to December 2015, 90 samples were collected from pond water of parks of 13 regions of Mashhad City. Physicochemical parameters were measured in situ. After filtering, the samples were cultured on Bacto-agar enriched with Escherichia coli. PCR analysis was conducted on the culture-positive samples, and then the PCR products were sequenced. Statistical analysis was performed by SPSS software and Fisher's Exact and Mann-Whitney test. RESULTS: Among the samples that were examined, 19 samples (21.1%) were positive for Acanthamoeba. The sequencing revealed that Acanthamoeba isolates belonged to T4 genotype of Acanthamoeba. There was no significant relationship between physicochemical parameters and the presence of Acanthamoeba. CONCLUSION: The prevalence of Acanthamoeba in pond water of parks was relatively high, but there was no significant relationship between physicochemical parameters and the presence of Acanthamoeba.

Soil carbon inventory to quantify the impact of land use change to mitigate greenhouse gas emissions and ecosystem services.

Currently the land use and land use change (LULUC) emits 1.3 ±â€¯0.5 Pg carbon (C) year-1, equivalent to 8% of the global annual emissions. The objectives of this study were to quantify (1) the impact of LULUC on greenhouse gas (GHG) emissions in a subtropical region and (2) the role of conservation agriculture to mitigate GHG emissions promoting ecosystem services. We developed a detailed IPCC Tier 2 GHG inventory for the Campos Gerais region of southern Brazil that has large cropland area under long-term conservation agriculture with high crop yields. The inventory accounted for historical and current emissions from fossil fuel combustion, LULUC and other minor sources. We used Century model to simulate the adoption of conservation best management practices, to all croplands in the region from 2017 to 2117. Our results showed historical (1930-2017) GHG emissions of 412 Tg C, in which LULUC contributes 91% (376 ±â€¯130 Tg C), the uncertainties ranged between 13 and 36%. Between 1930 and 1985 LULUC was a major source of GHG emission, however from 1985 to 2015 fossil fuel combustion became the primary source of GHG emission. Forestry sequestered 52 ±â€¯24 Tg C in 0.6 Mha in a period of 47 years (1.8 Tg C Mha-1 year-1) and no-till sequestered 30.4 ±â€¯24 Tg C in 2 Mha in a period of 32 years (0.5 Tg C Mha-1 year-1) being the principal GHG mitigating activities in the study area. The model predictions showed that best management practices have the potential to mitigate 13 years of regional emissions (330 Tg C in 100 years) or 105 years of agriculture, forestry and livestock emissions (40 Tg C in 100 years) making the agriculture sector a net carbon (C) sink and promoting ecosystem services.

Ozone exposure- and flux-based response relationships with photosynthesis of winter wheat under fully open air condition.

Five winter wheat cultivars were exposed to ambient (A-O3) and elevated (E-O3, 1.5 ambient) O3 in a fully open-air fumigation system in China. Ozone exposure- and flux based response relationships were established for seven physiological variables related to photosynthesis. The performance of the fitting of the regressions in terms of R2 increased when second order regressions instead of first order ones were used, suggesting that effects of O3 were more pronounced towards the last developmental stages of the wheat. The more robust indicators were those related with CO2 assimilation, Rubisco activity and RuBP regeneration capacity (Asat, Jmax and Vcmax), and chlorophyll content (Chl). Flux-based metrics (PODy, Phytotoxic O3 Dose over a threshold ynmolO3m-2s-1) predicted slightly better the responses to O3 than exposure metrics (AOTX, Accumulated O3 exposure over an hourly Threshold of X ppb) for most of the variables. The best performance was observed for metrics POD1 (Asat, Jmax and Vcmax) and POD3 (Chl). For this crop, the proposed response functions could be used for O3 risk assessment based on physiological effects and also to include the influence of O3 on yield or other variables in models with a photosynthetic component.

Culicidae (Diptera) community structure, spatial and temporal distribution in three environments of the province of Chaco, Argentina.

The aim of this work was to study the composition of the Culicidae community in three environments with different degrees of anthropic disturbance in the province of Chaco. The nonparametric richness estimator ACE was calculated to measure the completeness of the sampling in each environment, and the diversity of each environment (α-diversity) were estimated. The composition, abundance and uniformity of species from the different environments were compared by means of range-species curves. ß-diversity was measured as species complementarity, which allowed us to know the degree of dissimilarity among the environments. The synanthropic index was estimated, identifying urban environment (synanthropic) species, eusynanthropic species, and wild species. The influence of climatic factors (mean temperature, relative humidity and rainfall) on the monthly and annual variations of the identified mosquito species was analysed using multilevel Poisson models with over-dispersion. The wild environment showed higher diversity and the semi-urban environment higher species richness. Despite having lower S and abundance, the urban environment showed greater diversity than semi-urban environment, although it also showed lower completeness, which means S could increase. Anthropogenic disturbance can lead to the elimination and/or modification or substitution of habitats, with the subsequent loss of richness in the more sensitive species of Culicidae fauna, although the conditions are also favourable for the settling of opportunistic and exotic species well-adjusted to disturbed environments. Most of the species abundances were positively influenced by the analysed climatic variables. The study area showed a rich Culicidae fauna of public health significance, with a risk of pathogen transmission, suggesting the need of further studies and the febrile and entomological surveillance.

Rhodophyta de ambientes lóticos de Unidades de Conservação da região Sul do Brasil

Espécies de Rhodophyta de 10 Unidades de Conservação da região Sul do Brasil foram investigadas. As amostragens foram conduzidas em 105 segmentos de riachos consistindo em transeções de 10 m de comprimento. O levantamento florístico resultou em 80 populações representando três gêneros, Batrachospermum, Kumanoa e Hildenbrandia, além do estágios 'Chantransia'. Batrachospermum foi representado por cinco espécies (B. arcuatum Kylin, B. atrum (Hudson) Harvey, B. helminthosum Bory, B. keratophytum Bory, B. puiggarianum Grunow in Wittrock & Nordstedt). O gênero Kumanoa foi representado por K. abilii (Reis) Necchi Júnior & Vis e K. ambigua (Montagne) Entwisle et al., enquanto Hildenbrandia exclusivamente por H. angolensis W. West & G.S. West. Nossos resultados confirmam Batachospermum como o gênero melhor representado, em termos de número de espécies, entre as Rhdophyta de água doce. Batrachospermum arcuatum foi registrado pela primeira vez na região Sul do Brasil, ampliando assim, o limite austral de sua distribuição.

Species of Rhodophyta from 10 Conservation Units from the south region of Brazil were surveyed. The samplings were carried out in 105 stream reaches, consisting of 10 m length transects. The floristic survey involved 80 populations, representing three genera, Batrachospermum, Kumanoa and Hildenbrandia plus the 'Chantransia' stages. Batrachospermum was represented by five species (B. arcuatum Kylin, B. atrum (Hudson) Harvey, B. helminthosum Bory, B. keratophytum Bory and B. puiggarianum Grunow in Wittrock & Nordstedt). The genus Kumanoa was represented by K. abilii (Reis) Necchi Júnior & Vis and K. ambigua (Montagne) Entwisle et al., while Hildenbrandia only by H. angolensis W.West & G.S.West. Our results confirm Batachospermum as the best represented genus, in terms of species number, among freshwater Rhdophyta. B. arcuatum was a new record for the south region of Brazil, thus extending its austral distribution range.