scholarly journals Nematode community, trophic structure and population fluctuation in soybean fields

2003 ◽  
Vol 28 (3) ◽  
pp. 258-266 ◽  
Author(s):  
Gilmar S. Gomes ◽  
Shiou P. Huang ◽  
Juvenil E. Cares
Keyword(s):  
Rainy Season ◽  
Soil Fungi ◽  
Federal District ◽  
Dry Season ◽  
Temporal Sampling ◽  
Plant Parasite ◽  
Wide Range ◽  
Crop Cycle ◽  
Low Levels ◽  
Parasite Populations

Temporal (monthly in three fields for 12 months) and spatial (once in 23 fields during March-April) samplings were conducted in the major soybean (Glycine max)-growing region of the Brazilian Federal District. Fifty-three nematode genera were found in both samplings, but 13 were detected only by the temporal sampling, and one only by the spatial sampling. Fifty-three percent were plant-parasites, 35% were bacterivores, and about 12% were fungivores, predators and omnivores constituted the community that was dominated by the genera Helicotylenchus (40% of total abundance), Acrobeles (15%), Cephalobus (7.6%), Meloidogyne(5.6%) and Pratylenchus (4.9%). Heterodera glycines was not found in this study. There were no differences in ten ecological measurements [Ds, H', Es, T, FF/BF, (FF+BF)/PP, MI, PPI, mMI, and Dorylaimida (%)] between the two sampling types, but differences in indexes d and J'. Plant parasite populations dropped at the end of the crop cycle, remained at low levels during the dry season and the seedling period, then increased again in the crop-growing season. Fungivores maintained their low populations throughout the year, increasing only in June and July, the post-harvest period, when soil fungi decomposed root tissue. The population of bacterivores slightly declined during the dry season and the initial rainy season, but peaked in the middle of the rainy season, apparently associated with soil humidity. In the five most abundant nematodes, those of Acrobeles and Pratylenchus were more populous in wet soils, Cephalobus and Meloidogyne adapted well in dry soils, but Helicotylenchus survived abundantly in a wide range of soil moisture.

scholarly journals What are the main local drivers determining richness and fishery yields in tropical coastal fish assemblages?

2018 ◽  
Vol 35 ◽  
pp. 1-12
Author(s):  
Cynthia Diniz Souza ◽  
Vandick S. Batista ◽  
Nidia Noemi Fabré
Keyword(s):  
Wind Speed ◽  
Rainy Season ◽  
Fish Assemblages ◽  
Principal Component ◽  
Dry Season ◽  
Community Diversity ◽  
Tropical Species ◽  
Coastal Fish ◽  
Wide Range ◽  
Diversity Profiles

Seasonal ecological effects caused by temperature and photoperiod are typically considered minimal in the tropics. Nevertheless, annual climate cycles may still influence the distribution and abundance of tropical species. Here, we investigate whether seasonal patterns of precipitation and wind speed influence the structure of coastal fish assemblages and fishing yields in northeast Brazil. Research trips were conducted during the rainy and dry seasons using commercial boats and gear to sample the fish community. Diversity was analyzed using abundance Whittaker curves, diversity profiles and the Shannon index. Principal Component Analysis (PCA) was used to analyze associations between the abundance of species and various environmental variables related to seasonality. A total of 2,373 fish were collected, representing 73 species from 34 families – 20 of which were classified as both frequent and abundant. Species richness was greater and more equitable during the rainy season than the dry season – driven by changes in the precipitation rather than to wind speed. Species diversity profiles were slightly greater during the rainy season than the dry season, but this difference was not statistically significant. Using PCA was identified three groups of species: the first associated with wind speed, the second with precipitation, and the third with a wide range of sampling environments. This latter group was the largest and most ecologically heterogeneous. We conclude that tropical coastal fish assemblages are largely influenced by local variables, and seasonally mediated by annual changes related to precipitation intensity and wind speed, which in turn influences fishery yields.

scholarly journals What are the main local drivers determining richness and fishery yields in tropical coastal fish assemblages?

2018 ◽  
Vol 35 ◽  
pp. 1-12 ◽  
Author(s):  
Cynthia Diniz Souza ◽  
Vandick S. Batista ◽  
Nidia Noemi Fabré
Keyword(s):  
Wind Speed ◽  
Rainy Season ◽  
Fish Assemblages ◽  
Principal Component ◽  
Dry Season ◽  
Community Diversity ◽  
Tropical Species ◽  
Coastal Fish ◽  
Wide Range ◽  
Diversity Profiles

Seasonal ecological effects caused by temperature and photoperiod are typically considered minimal in the tropics. Nevertheless, annual climate cycles may still influence the distribution and abundance of tropical species. Here, we investigate whether seasonal patterns of precipitation and wind speed influence the structure of coastal fish assemblages and fishing yields in northeast Brazil. Research trips were conducted during the rainy and dry seasons using commercial boats and gear to sample the fish community. Diversity was analyzed using abundance Whittaker curves, diversity profiles and the Shannon index. Principal Component Analysis (PCA) was used to analyze associations between the abundance of species and various environmental variables related to seasonality. A total of 2,373 fish were collected, representing 73 species from 34 families – 20 of which were classified as both frequent and abundant. Species richness was greater and more equitable during the rainy season than the dry season – driven by changes in the precipitation rather than to wind speed. Species diversity profiles were slightly greater during the rainy season than the dry season, but this difference was not statistically significant. Using PCA was identified three groups of species: the first associated with wind speed, the second with precipitation, and the third with a wide range of sampling environments. This latter group was the largest and most ecologically heterogeneous. We conclude that tropical coastal fish assemblages are largely influenced by local variables, and seasonally mediated by annual changes related to precipitation intensity and wind speed, which in turn influences fishery yields.

scholarly journals Ocorrência de flebotomíneos (Diptera: Psychodidae) em matas de galeria no Distrito Federal, Brasil

2014 ◽  
Vol 7 (3) ◽  
pp. 216-221 ◽  
Author(s):  
Jônatas Barbosa Cavalcante Ferreira ◽  
Mariana Aragão Macedo ◽  
Douglas de Almeida Rocha ◽  
Tauana de Sousa Ferreira ◽  
Marcos Takashi Obara ◽  
...  
Keyword(s):  
Rainy Season ◽  
Conservation Status ◽  
Ground Level ◽  
Federal District ◽  
Dry Season ◽  
Sand Fly ◽  
Sand Flies ◽  
Phlebotomine Sand Flies ◽  
Gallery Forests ◽  
Distrito Federal

O objetivo deste estudo foi analisar a ocorrência de flebotomíneos em matas de galeria do Distrito Federal (DF), em diferentes estações climáticas, estratos verticais e condições de preservação das matas. As capturas foram realizadas em três áreas na Fazenda Água Limpa da Universidade de Brasília. Em cada área foi analisada a ocorrência de flebotomíneos em 20 pontos visitados em dois meses, novembro de 2012 (estação chuvosa) e maio de 2013 (estação seca). Armadilhas luminosas HP foram instaladas a 1,5 m e a 10 m de altura do solo, operando entre 17:00 e 07:00 h, por três dias consecutivos. Foram instaladas 359 armadilhas-noite na estação chuvosa e 291 na seca. Nenhum flebotomíneo foi capturado na estação chuvosa. Na estação seca foram capturados 250 exemplares. As espécies identificadas foram Psathyromyia runoides (Fairchild & Hertig) (79,9%), Pintomyia monticola (Costa Lima) (9,7%), Micropygomyia quinquefer (Dyar) (3,7%), Psathyromyia shannoni (Dyar) (3%), Bichromomyia flaviscutellata (Mangabeira) (0,7%), Brumptomyia sp. (0,7%), Pintomyia kuscheli (Le Pont, Martinez, Torrez-Espejo & Dujardin) (0,7%), Psathyromyia lutziana (Costa Lima) (0.7%) e Sciopemyia sordellii (Shannon & Del Ponte) (0,7%). Os resultados indicam que em matas de galeria do DF há uma maior ocorrência de flebotomíneos na estação seca, no nível do solo e em áreas preservadas. Registra-se pela primeira vez Pa. runoides, Pi. kuscheli e Mi. quinquefer no DF. Occurrence of Phlebotomine Sand Flies (Diptera: Psychodidae) in the Gallery Forests of the Federal District, Brazil Abstract. We analyzed the occurrence of phlebotomine sand flies in the gallery forests of the Federal District (FD), in different seasons, forest strata and conservation status. The samples were collected in three areas in the Água Limpa Farm, University of Brasília. In each area the occurrence data were analyzed in 20 collection sites visited on two months, November 2012 (rainy season) and May 2013 (dry season). HP light traps were installed at 1.5 m and 10 m above the ground operating from 17:00 to 7:00 h, during three consecutive days. We set 359 trap-nights during the rainy season and 291 during the dry season. None sand fly was caught during the rainy season. In the dry season 250 sand flies were captured. The identified species were Psathyromyia runoides (Fairchild & Hertig) (79.9%), Pintomyia monticola (Costa Lima) (9.7%), Micropygomyia quinquefer (Dyar) (3.7%), Psathyromyia shannoni (Dyar) (3%), Bichromomyia flaviscutellata (Mangabeira) (0.7%), Brumptomyia sp. (0.7%), Pintomyia kuscheli (Le Pont, Martinez, Torrez-Espejo & Dujardin) (0.7%), Psathyromyia lutziana (Costa Lima) (0.7%), and Sciopemyia sordellii (Shannon & Del Ponte) (0.7%). The results indicated that in the gallery forests of the FD there is a higher occurrence of sand flies in the dry season, at ground level and in preserved areas. Pa runoides, Pi. kuscheli and Mi. quinquefer were recorded for the first time in the FD.  

STUDI BIONOMIK VEKTOR MALARIA DI KECAMATAN KALIBAWANG, KULONPROGO

2018 ◽  
Vol 4 (2) ◽  
Author(s):  
Sardjito Eko Windarso dkk
Keyword(s):  
Land Use ◽  
Malaria Vector ◽  
Rainy Season ◽  
Dry Season ◽  
Physical Factors ◽  
Mosquito Vector ◽  
Anopheles Species ◽  
Commercial Farming ◽  
Study Results ◽  
Dry And Rainy Seasons

The increasing of malaria cases in recent years at Kecamatan Kalibawang has been suspected correspond with the conversion of farming land-use which initiated in 1993. Four years after the natural vegetation in this area were changed become cocoa and coffee commercial farming estates, the number of malaria cases in 1997 rose more than six times, and in 2000 it reached 6085. This study were aimed to observe whether there were any differences in density and diversity of Anopheles as malaria vector between the cocoa and mix farming during dry and rainy seasons. The results of the study are useful for considering the appropriate methods, times and places for mosquito vector controlling. The study activities comprised of collecting Anopheles as well as identifying the species to determine the density and diversity of the malaria vector. Both activities were held four weeks in dry season and four weeks in rainy season. The mea-surement of physical factors such as temperature, humidity and rainfall were also conducted to support the study results. Four dusuns which meet the criteria and had the highest malaria cases were selected as study location. Descriptively, the results shows that the number of collected Anopheles in cocoa farming were higher compared with those in mix horticultural farming; and the number of Anopheles species identifi ed in cocoa farming were also more varied than those in the mix horticultural farming.Key words: bionomik vektor malaria, anopheles,

scholarly journals Understanding variability in greenhouse gas emission estimates of smallholder dairy farms in Indonesia

2021 ◽  
Author(s):  
Titis Apdini ◽  
Windi Al Zahra ◽  
Simon J. Oosting ◽  
Imke J. M. de Boer ◽  
Marion de Vries ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Rainy Season ◽  
Greenhouse Gas Emission ◽  
Dairy Farms ◽  
Dry Season ◽  
Enteric Fermentation ◽  
Tropical Regions ◽  
Population Mean ◽  
Smallholder Dairy ◽  
Smallholder Dairy Farms

Abstract Purpose Life cycle assessment studies on smallholder farms in tropical regions generally use data that is collected at one moment in time, which could hamper assessment of the exact situation. We assessed seasonal differences in greenhouse gas emissions (GHGEs) from Indonesian dairy farms by means of longitudinal observations and evaluated the implications of number of farm visits on the variance of the estimated GHGE per kg milk (GHGEI) for a single farm, and the population mean. Methods An LCA study was done on 32 smallholder dairy farms in the Lembang district area, West Java, Indonesia. Farm visits (FVs) were performed every 2 months throughout 1 year: FV1–FV3 (rainy season) and FV4–FV6 (dry season). GHGEs were assessed for all processes up to the farm-gate, including upstream processes (production and transportation of feed, fertiliser, fuel and electricity) and on-farm processes (keeping animals, manure management and forage cultivation). We compared means of GHGE per unit of fat-and-protein-corrected milk (FPCM) produced in the rainy and the dry season. We evaluated the implication of number of farm visits on the variance of the estimated GHGEI, and on the variance of GHGE from different processes. Results and discussion GHGEI was higher in the rainy (1.32 kg CO2-eq kg−1 FPCM) than in the dry (0.91 kg CO2-eq kg−1 FPCM) season (P < 0.05). The between farm variance was 0.025 kg CO2-eq kg−1 FPCM in both seasons. The within farm variance in the estimate for the single farm mean decreased from 0.69 (1 visit) to 0.027 (26 visits) kg CO2-eq kg−1 FPCM (rainy season), and from 0.32 to 0.012 kg CO2-eq kg−1 FPCM (dry season). The within farm variance in the estimate for the population mean was 0.02 (rainy) and 0.01 (dry) kg CO2-eq kg−1 FPCM (1 visit), and decreased with an increase in farm visits. Forage cultivation was the main source of between farm variance, enteric fermentation the main source of within farm variance. Conclusions The estimated GHGEI was significantly higher in the rainy than in the dry season. The main contribution to variability in GHGEI is due to variation between observations from visits to the same farm. This source of variability can be reduced by increasing the number of visits per farm. Estimates for variation within and between farms enable a more informed decision about the data collection procedure.

scholarly journals Directional Distance Function Technical Efficiency of Chili Production in Thailand

2021 ◽  
Vol 13 (2) ◽  
pp. 741
Author(s):  
Wirat Krasachat ◽  
Suthathip Yaisawarng
Keyword(s):  
Distance Function ◽  
Rainy Season ◽  
Sample Selection ◽  
Agricultural Practices ◽  
Directional Distance Function ◽  
Dry Season ◽  
Small Samples ◽  
Function Technique ◽  
Security Problem ◽  
Gap Technology

To overcome the challenging food safety and security problem, in 2003, the Thai government initiated ‘Good Agricultural Practices’ (GAP) technology. This paper used a sample of 107 small chili farms from the Chiyaphoom province for the 2012 crop year, and data envelopment analysis (DEA) meta-frontier directional distance function technique to answer two questions: (1) Are GAP-adopting farms, on average, more efficient than conventional farms? (2) Does access to GAP technology affect farmers’ decisions to adopt GAP technology? We also developed an ‘indirect’ approach to reduce the potential sample selection bias for small samples. For the dry-season subsample, GAP farms were more technically efficient when compared with non-GAP farms. These dry-season non-GAP farms may not adopt the GAP method because they have limited access to GAP technology. For the rainy-season subsample, on average, GAP farms were more efficient than non-GAP farms at the 5% level. Access to the GAP technology is not a possible reason for non-GAP rainy season farms to not adopt the GAP technology. To enable sustainable development, government agencies and nongovernmental organizations (NGOs) must develop and implement appropriate educational and training workshops to promote and assist GAP technology adoption for chili farms in Thailand.

scholarly journals Application of Sentinel-1 and-2 Images in Measuring the Deformation of Kuh-e-Namak (Dashti) Namakier, Iran

2021 ◽  
Vol 13 (4) ◽  
pp. 785
Author(s):  
Sen Zhang ◽  
Qigang Jiang ◽  
Chao Shi ◽  
Xitong Xu ◽  
Yundi Gong ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Rock Salt ◽  
Rainy Season ◽  
Surface Deformation ◽  
Meteorological Data ◽  
Dry Season ◽  
Synthetic Aperture ◽  
Advantages And Disadvantages ◽  
Sbas Insar ◽  
Aperture Radar

Kuh-e-Namak (Dashti) namakier is one of the most active salt diapirs along the Zagros fold–thrust belt in Iran. Its surface deformation should be measured to estimate its long-term kinematics. Ten Sentinel-2 optical images acquired between October 2016 and December 2019 were processed by using Co-Registration of Optically Sensed Images and Correlation (COSI-Corr) method. Forty-seven Sentinel-1 ascending Synthetic Aperture Radar (SAR) images acquired between April 2017 and December 2019 were processed by using Small Baseline Subset Synthetic Aperture Radar Interferometry (SBAS-InSAR) method. The deformation of Kuh-e-Namak (Dashti) namakier was measured using both methods. Then, meteorological data were utilized to explore the relationship between the kinematics of the namakier and weather conditions and differences in macrodeformation behavior of various rock salt types. The advantages and disadvantages of COSI-Corr and SBAS-InSAR methods in measuring the deformation of the namakier were compared. The results show that: (1) The flank subsides in the dry season and uplifts in the rainy season, whereas the dome subsides in the rainy season and uplifts in the dry season. Under extreme rainfall conditions, the namakier experiences permanent plastic deformation. (2) The “dirty” rock salt of the namakier is more prone to flow than the “clean” rock salt in terms of macrodeformation behavior. (3) In the exploration of the kinematics of the namakier via the two methods, COSI-Corr is superior to SBAS-InSAR on a spatial scale, but the latter is superior to the former on a time scale.

scholarly journals Seasonal Differences in Cyclospora cayetanensis Prevalence in Colombian Indigenous People

2021 ◽  
Vol 9 (3) ◽  
pp. 627
Author(s):  
Hagen Frickmann ◽  
Juliane Alker ◽  
Jessica Hansen ◽  
Juan Carlos Dib ◽  
Andrés Aristizabal ◽  
...  
Keyword(s):  
Indigenous People ◽  
Rainy Season ◽  
Gastrointestinal Symptoms ◽  
Dry Season ◽  
Seasonal Effects ◽  
Chain Reaction ◽  
Resource Limited Settings ◽  
Resource Limited ◽  
Stool Samples ◽  
Polymerase Chain

Fecal-orally transmitted cyclosporiasis is frequent in remote resource-limited settings in Central and South America with poor hygiene conditions. In this study, we aimed at assessing seasonal effects on the epidemiology of colonization or infection with C. cayetanensis in Colombian indigenous people living under very restricted conditions. In the rainy season between July and November and in the dry season between January and April, stool samples from indigenous people with and without gastrointestinal symptoms were collected and screened for C. cayetanensis applying in-house real-time polymerase chain reaction (PCR). In the rainy season and in the dry season, positive PCR results were observed for 11.8% (16/136) and 5.1% (15/292), respectively, with cycle threshold (Ct) values of 30.6 (±3.4) and 34.4 (±1.6), respectively. Despite higher parasite loads in the rainy season, fewer individuals (2/16, 12.5%) reported gastrointestinal symptoms compared to the dry season (6/15, 40%). In conclusion, considerable prevalence of C. cayetanensis in Colombian indigenous people persists in the dry season. Low proportions of gastrointestinal symptoms along with higher parasite loads make colonization likely rather than infection.

scholarly journals Nocturnal Boundary Layer Erosion Analysis in the Amazon Using Large-Eddy Simulation during GoAmazon Project 2014/5

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 240
Author(s):  
Rayonil Carneiro ◽  
Gilberto Fisch ◽  
Theomar Neves ◽  
Rosa Santos ◽  
Carlos Santos ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Large Eddy Simulation ◽  
Rainy Season ◽  
Nocturnal Boundary Layer ◽  
Enso Event ◽  
Dry Season ◽  
Dry Period ◽  
Additional Energy ◽  
Eddy Simulation ◽  
Large Eddy

This study investigated the erosion of the nocturnal boundary layer (NBL) over the central Amazon using a high-resolution model of large-eddy simulation (LES) named PArallel Les Model (PALM) and observational data from Green Ocean Amazon (GoAmazon) project 2014/5. This data set was collected during four intense observation periods (IOPs) in the dry and rainy seasons in the years 2014 (considered a typical year) and 2015, during which an El Niño–Southern Oscillation (ENSO) event predominated and provoked an intense dry season. The outputs from the PALM simulations represented reasonably well the NBL erosion, and the results showed that it has different characteristics between the seasons. During the rainy season, the IOPs exhibited slow surface heating and less intense convection, which resulted in a longer erosion period, typically about 3 h after sunrise (that occurs at 06:00 local time). In contrast, dry IOPs showed more intensive surface warming with stronger convection, resulting in faster NBL erosion, about 2 h after sunrise. A conceptual model was derived to investigate the complete erosion during sunrise hours when there is a very shallow mixed layer formed close to the surface and a stable layer above. The kinematic heat flux for heating this layer during the erosion period showed that for the rainy season, the energy emitted from the surface and the entrainment was not enough to fully heat the NBL layer and erode it. Approximately 30% of additional energy was used in the system, which could come from the release of energy from biomass. The dry period of 2014 showed stronger heating, but it was also not enough, requiring approximately 6% of additional energy. However, for the 2015 dry period, which was under the influence of the ENSO event, it was shown that the released surface fluxes were sufficient to fully heat the layer. The erosion time of the NBL probably influenced the development of the convective boundary layer (CBL), wherein greater vertical development was observed in the dry season IOPs (~1500 m), while the rainy season IOPs had a shallower layer (~1200 m).

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