Dry Season Months Research Articles

Bio-Optical Properties of Two Neigboring Coastal Regions of Tropical Northern Australia: The Van Diemen Gulf and Darwin Harbour

This study focuses on the seasonal and spatial characterization of inherent optical properties and biogeochemical concentrations in the Van Diemen Gulf and Darwin Harbour, two neighboring tropical coastal environments of Northern Australia that exhibit shallow depths (~20 m), large (> 3 m) semi-diurnal tides and a monsoonal climate. To gain insight in the functioning of these optically complex coastal ecosystems, a total of 23 physical, biogeochemical and optical parameters were sampled at 63 stations during three field campaigns covering the 2012 wet and dry seasons, and the 2013 dry season. The total light absorption budget in the Van Diemen Gulf was dominated by non-algal particles (aNAP; >45%) during the dry season (May-October) and colored dissolved organic matter (aCDOM; 60%) during the wet season (November-April). The combined absorption by aNAP and aCDOM generally exceeded 70% of the total absorption budget from 400 to 620 nm, with phytoplankton, aPhy, accounting for less than 20%. In Darwin Harbour, where only the dry season conditions were sampled, the total absorption budget was dominated by an equivalent contribution of aCDOM, aNAP and phytoplankton. The major processes explaining the seasonal variability observed in the Van Diemen Gulf are resuspension from seasonal south-easterly trade winds in combination with the tidal energy and shallow bathymetry during the dry season months, and mostly terrestrial river runoff during the monsoon which discharge terrestrial CDOM from the surrounding wetlands. Due to light-limited conditions all year round, the particulate scattering coefficient (bp(555)) contributed significantly (90%) to the beam attenuation coefficient c(555), thus strongly limiting phytoplankton growth (Chlorophyll a~1 mg.m-3). Spatially, the Van Diemen Gulf had higher total suspended solids and nutrient concentrations than Darwin Harbour, with dissolved organic carbon and aCDOM subjected to photobleaching during the dry season. Key bio-optical relationships derived from this comprehensive set of parameters, the first ever to be collected in this tropical coastal environment, were successfully used for a region-specific seasonal parameterization of a Linear Matrix Inversion-based ocean color algorithm. Challenges related to the parameterization, and the use, of ocean color remote sensing algorithms for these optically complex waters are discussed.

Seasonal Pattern of Mycobacterium ulcerans, the Causative Agent of Buruli Ulcer, in the Environment in Ghana

This study aimed to contribute to the understanding of Mycobacterium ulcerans (MU) ecology by analysing both clinical and environmental samples collected from ten communities along two major river basins (Offin and Densu) associated with Buruli ulcer (BU) at different seasons. We collected clinical samples from presumptive BU cases and environmental samples from ten communities. Following DNA extraction, clinical samples were confirmed by IS2404 PCR and environmental samples were confirmed by targeting MU-specific genes, IS2404, IS2606 and the ketoreductase (KR) using real-time PCR. Environmental samples were first analysed for IS2404; after which, IS2404-positive samples were multiplexed for the IS2606 and KR gene. Our findings indicate an overall decline in BU incidence along both river basins, although incidence at Densu outweighs that of Offin. Overall, 1600 environmental samples were screened along Densu (434, 27 %) and Offin (1166, 73 %) and MU was detected in 139 (9 %) of the combined samples. The positivity of MU along the Densu River basin was 89/434 (20.5 %), whilst that of the Offin River basin was 50/1166 (4.3 %). The DNA was detected mainly in snails (5/6, 83 %), moss (8/40, 20 %), soil (55/586, 9 %) and vegetation (55/675, 8 %). The proportion of MU positive samples recorded was higher during the months with higher rainfall levels (126/1175, 11 %) than during the dry season months (13/425, 3 %). This study indicates for the first time that there is a seasonal pattern in the presence of MU in the environment, which may be related to recent rainfall or water in the soil.

Effect of projected climate change on the hydrological regime of the Yangtze River Basin, China

The hydrological response to the potential future climate change in Yangtze River Basin (YRB), China, was assessed by using an ensemble of 54 climate change simulations. The Coupled Model Intercomparison Project 5 simulations under two new Representative Concentration Pathways (RCP) 4.5 and 8.5 emission scenarios were downscaled and used to drive the Variable Infiltration Capacity hydrological model. This study found that the range of temperature changes is homogeneous for almost the entire region, with an average annual increase of more than 2 °C under RCP4.5 and even more than 4 °C under RCP8.5 in the end of the twenty first century. The warmest period (June–July–August) of the year would experience lower changes than the colder ones (December–January–February). Overall, mean precipitation was projected to increase slightly in YRB, with large dispersion among different global climate models, especially during the dry season months. These phenomena lead to changes in future streamflow for three mainstream hydrological stations (Cuntan, Yichang, and Datong), with slightly increasing annual average streamflows, especially at the end of twenty first century. Compared with the percentage change of mean flow, the high flow shows (90th percentile on the probability of no exceedance) a higher increasing trend and the low flow (10th percentile) shows a decreasing trend or lower increasing trend. The maximum daily discharges with 5, 10, 15, and 30-year return periods show an increasing trend in most sub-basins in the future. Therefore, extreme hydrological events (e.g., floods and droughts) will increase significantly, although the annual mean streamflow shows insignificant change. The findings of this study would provide scientific supports to implement the integrated adaptive water resource management for climate change at regional scales in the YRB.

AGROBIODIVERSIDADE EM QUINTAIS COMO ESTRATÉGIA PARA SOBERANIA ALIMENTAR NO SEMIÁRIDO NORTE MINEIRO

<p>A agrobiodiversidade engloba toda diversidade biológica manejada pelos agricultores/as para produção agrícola, seus saberes e práticas ancestrais associados. Neste trabalho, investigou-se a agrobiodiversidade e suas implicações na soberania alimentar de diferentes comunidades tradicionais do norte mineiro, utilizando os <em>quintais</em> como foco de estudo. Para tanto, foram realizadas entrevistas semi-estruturadas em domicílios e nos respectivos <em>quintais </em>amostrados, reuniões e grupos focais em cada comunidade parceira, a saber: quilombola de Malhada Grande (Catuti/MG), vazanteira do Pau Preto (Matias Cardoso/MG), geraizeira do Sobrado (Rio Pardo de Minas/MG) e caatingueira do Touro (Serranópolis de Minas/MG). Em geral, segundo os parceiros, o <em>“quintal”</em> engloba: local ao redor da casa com plantio, criação de animais, trato diário, podendo ou não haver árvores. Nele encontram-se diferentes espaços, como a <em>horta</em> onde se cultivam plantas de ciclo curto. A importância local dos quintais para diversos fins foi revelada nos depoimentos, como no autossustento, permutas/partilhas de plantas e frutos, uso medicinal e <em>loci</em> de relações familiares e comunitárias. Registraram-se 133 etnoespécies, distribuídas em 126 espécies e 46 famílias botânicas, nos agroecossistemas de quintais estudados. Entre os diferentes usos alimentares elencados(83), organizou-se 15 categorias de preparo e consumo, nas quais se destacaram (i)consumo <em>in natura </em>e (ii)bebidas, pela maior riqueza de etnoespécies. A disponibilidade temporal dessa agrobiodiversidade é marcada pela sazonalidade, que define um ciclo anual fundamental: <em>tempo das águas</em> e <em>tempo das secas</em>; representando seis meses corridos de chuvas e estiagem, respectivamente. Em cada tempo do ciclo, as fases intermediárias revelaram maior porcentagem de etnoespécies/comunidade em produção, denotando etnoespécies e etnovariedades sazonalmente específicas, adaptadas ao clima semiárido regional. Conclui-se que os quintais, ambientes manejados, representam extensão cultural de tradições alimentares locais, revelam agrobiodiversidade notavelmente rica, cuja conservação e valorização são algumas das diversas estratégias agroalimentares que comunidades tradicionais têm para manter e garantir a alimentação, fundamentais na soberania alimentar.<strong></strong></p>

Survey of Livestock Management and Protein Consumption in Rural Villages of Malawi

ObjectivesThere were 2 objectives: 1) to survey livestock (sheep, goats, beef, poultry, swine, horses, or other) ownership and management methods and 2) to survey consumption habits of livestock-derived protein (meat, milk, or eggs) in rural villages of Malawi.Materials and MethodsSurveys were conducted in villages of 11 different communities throughout central Malawi during 2 dry season months. Translators fluent in both languages translated survey responses orally from Chichewa to English. The questionnaire provided categorical options for response to each question. If participants selected “other”, they were asked to detail their response. Respondents were allowed to indicate multiple responses when applicable. Part I of the surveys addressed livestock ownership details, including number of each species if applicable, primary use of livestock (income, consumption, transportation, etc.) as well as general questions about animal housing and management. Part II asked about livestock derived protein consumption habits (from sheep, goats, swine, cattle, poultry, wild game, or other) for the household, by protein type and frequency of consumption. Full survey completion success was 81.3% (26/32).ResultsAge of survey participants ranged from 30 to 75 yr, with an average age of 51 yr of age. All survey respondents (n = 32) owned 1 or more livestock species. Goats or sheep were the most commonly owned species (87.5%, 28/32), followed by chickens (78.1%. 25/32), with horses being the least frequently owned (3.2%, 1/32). All survey respondents utilize one or more species of livestock as an income source, with 75.04% (24/32) also using one or more species of their livestock as a protein source.Of those surveyed, 34.6% (9/26) reported daily consumption of protein, with the most frequently consumed protein source on a daily basis reported as eggs (19.2%, 5/26), and by mice and other rodents (19.2%, 5/26). Poultry was consumed 2 to 3 times per month (34.6%, 9/26) or once a month (34.6%, 9/26). Most respondents consumed sheep and goats either once a moth (30.8, 8/26) or 2 to 3 times per a month (19.2%, 5/26). Species most commonly selected as never consumed by those surveyed were wild game (69.2%, 18/26), beef (57.7%, 15/26) and pork (42.3%, 11/26).ConclusionResults from these surveys can be used to better understand livestock management techniques, as well as livestock species most commonly found in rural villages of Malawi. Additionally, the results of species most readily available and current consumption habits can provide direction for development of educational materials and training programs to improve the availability of protein and iron to combat anemia.

Assessing the impact of climate change on the water intake of the headworks on the Red River Basin in Viet Nam

The irrigation systems for the Red River Delta usually get water by pumping and gravity.The results determine the possible minimum water level line in the dry-season months under climate change scenarios (B2, SC5 and SC6 and current scenario is B2, SC4) on the river system of the Red River – Thai Binh River in study areas of project as below: Water levels on the Red River in the dry season under climate change scenarios significantly reduced compared with 2010. At Ha Noi station on Red River, the water levels reduce in 2050 about 6.5cm (B2) and 7.5cm (A2) and 6cm (B1). At Nam Dinh station on Dao River, the water levels reduce in 2050 about 4cm (B2) and 5cm (A2) and 3cm (B1). At Cat Khe on Thai Binh River, the water levels reduce in 2050 about 2cm (B2) and 3cm (A2) and 1.5cm (B1). At An Bai on Kinh Thay River, the water levels reduce in 2050 about 5cm (B2) and 6cm (A2) and 4cm (B1). At Truc Phuong on Ninh Co River, the water levels reduce in 2050 about 6.5cm (B2) and 7.2cm (A2) and 5.8cm (B1). In the scenario in which 50% of the socio-economic development plans are achieved (SC6), the water demand is lower than the scenario of full development (SC5). The decrease in the average water level in the whole Red River system is about 1.3-1.8 cm less than in SC5, and in Thai Binh river this figure is about 1.4-2.1cm. The lowering of the water level under climate change in the river has caused problems for irrigation during the dry season, in order to reach the target level in Hanoi.

Assessment of physico-chemical parameters of River Kaduna and College of Agriculture and Animal Science Dam, (CAAS) Kaduna, Nigeria

River Kaduna is one of the major sources of water to the inhabitants of the communities around the river and also to fish farmers while College of Agriculture and Animal Science Dam (CAAS) is used for fish farming and also for domestic purpose. The study was carried out to assess Physicochemical Parameters of River Kaduna and College of Agriculture and Animal Science Dam, Kaduna. The result of seasonal variation of physicochemical parameters between River Kaduna and College of Agriculture and Animal Science Dam, revealed that the atmospheric temperature (AT) ranged from 32.8 to 33.60C, pH at 7.1, conductivity ranged from 83.7 to 139.7µs/cm, dissolved oxygen ranged from 9.2 to 9.4 mg/l, biological oxygen demand ranged from 5.2 to 5.9 mg/l, water temperature (WT) at 29.20C, total hardness ranged from 37.4 to 58.0 mg/l, alkalinity ranged from 18.8 ton29.7 mg/l, chloride ranged from 14.8 to 15.9 mg/l, nitrate and phosphorus ranged from 0.1 to 0.2 mg/l while transparency ranged from 21.4 to 22.3 cm respectively. The seasonal variation result revealed that both at the Dam and river, AT, pH, DO, WT, Chloride, Nitrate, Phosphorus and Transparency values were not significantly different while conductivity, BOD, TH, Alkalinity and Ammonia were significantly different. However, they were significantly difference from one month to another (wet and dry season months respectively).Keywords: Physico-chemical parameters, River Kaduna, CAAS Dam

Surface energy exchange in a tropical montane cloud forest environment: Flux partitioning, and seasonal and land cover-related variations

Relationships between seasonal climate, land cover and surface energy exchange in tropical montane cloud forest environments are poorly understood. The goal of this study was to investigate the seasonality of flux partitioning in lower montane cloud forest (LMCF), shaded coffee (CO) and sugarcane (SU) in central Veracruz, Mexico, as well as to evaluate the changes in surface energy exchange associated with the conversion of LMCF to CO or SU. Sensible (H) and latent heat (λE) fluxes were measured during the late dry and wet seasons using eddy covariance (CO and SU) and sap flow (LMCF) methods. Other measurements included: meteorological parameters, radiation balance, soil heat flux, soil moisture and vegetation characteristics. During the wet-season month of July, average midday Bowen ratios (βs) for sunny conditions were lowest and least variable among land covers: 0.4±0.2 (SE) in LMCF, 0.5±0.1 in SU and 0.7±0.1 in CO. In contrast, during the late dry-season months of March and April, βs were higher (i.e. higher H and lower λE) and more variable. The highest values of β were observed in LMCF, reflecting effects of partial leaf-shedding by dominant deciduous species (2.4±0.8, March) and increased stomatal control (1.4±0.3, April). There was also evidence of stomatal limitation of λE in CO and SU, having βs of up to 1.0±0.1 in April and March, respectively. As compared to LMCF, the average midday available energy (Ae) for sunny conditions was very similar in CO (−3±7%) and 15±8% lower in SU. Although not all results were statistically significant, they suggest that for the wet season conversion of LMCF to shaded coffee or sugarcane led to a decrease of 15±14% or 15±17% in midday λE under sunny conditions, respectively, whereas corresponding values of H increased by 37±38% or remained about the same (−4±40%). In contrast, for the late dry season, conversion of LMCF to shaded coffee or sugarcane appears to have resulted in higher λE and lower H, with changes of, respectively, +79 (±32)%/–45 (±16)% (CO) or +39 (±32)%/–43 (±16)% (SU) for a partially leafless LMCF in March, and +17 (±16)%/–11 (±16)% (CO) for a fully-leafed LMCF in April. In order to more accurately quantify the changes in surface energy fluxes associated with LMCF conversion, future work should focus on reducing the errors in the flux estimates. Nevertheless, for sunny days during the wet season, potential changes in the moisture and heat content of the local atmosphere due to the conversion of LMCF to CO or SU seem to have been in the same direction as those induced by increased greenhouse gases (drying and warming), whereas for the late dry season the effects appear to have been opposite (moistening and cooling).

Effects of Climate on Chicken Production in Ilorin, Kwara State, Nigeria

This paper explores the role which climate plays on the severity of diseases and seasonal mortality rate of chicken in the guinea savanna ecological zone of Kwara State, Nigeria. Data on climate and mortality rate of chicken collected over a period of 23 years (1991-2013) were partitioned according to characteristics weather types. Correlation and simple regression methods were used to analyse the data. The results of the analyses showed that weather types of each season affect outbreak of various diseases and mortality rate differently. In the dry season weather types outbreak of Newcastle and Gumboro diseases prevailed mostly during harmattan when mortality rate of chicken exhibited a strong positive relationship of 0.711 with rainfall and a strong negative relationship of 0.604 with maximum temperature. The last two months of dry season (March-April) witnessed the reverse of the above but with Newcastle disease and heat stress plaguing chicken production. The most prevalent chicken disease of rainy season in the study area is Coccidiosis. During the first weather type of wet season (two months before August break) mortality rate of chicken exhibited a strong positive relationship of 0.861 and 0.845 before August break, 0.775 and 0.894 during August break with both rain fall and relative humidity. However the relationship was negative with both maximum and minimum temperatures. Suggestions are made on how to manage both major weather types and poultry operation for efficient poultry farm development in the tropics.

An NDVI analysis of vegetation trends in an Andean watershed

We performed a Landsat 5-TM derived normalized difference vegetation index (NDVI) analysis in a semi-arid watershed (2700 km2) in the Andes of southern Peru from 1985 to 2010. There, pastoralists rely on wetlands (bofedales) particularly during dry season months and in drought. We calculated annual dry season NDVI for 20 of the 26 years from 1985 to 2010 and used the mean to delineate wetlands in the watershed. To investigate the trends in NDVI, a multiple regression model with the covariates precipitation, temperature, Julian day, and year of image acquisition was performed on each cell (three million individual regressions). Results indicate there is a modest increase in NDVI for the majority of cells (81 %) in the watershed. Approximately 30 % of wetland areas display a decrease in NDVI. Dry season NDVI is moderately correlated with wet season precipitation (R2 = 0.56, p < 0.05) but absent a trend in precipitation, NDVI trends are not explained by this variable. Changes in land management may result in more intensive use of wetlands, causing the decreasing vegetation trends in some locations.

Amazon forest structure generates diurnal and seasonal variability in light utilization

Abstract. The complex three-dimensional (3-D) structure of tropical forests generates a diversity of light environments for canopy and understory trees. Understanding diurnal and seasonal changes in light availability is critical for interpreting measurements of net ecosystem exchange and improving ecosystem models. Here, we used the Discrete Anisotropic Radiative Transfer (DART) model to simulate leaf absorption of photosynthetically active radiation (lAPAR) for an Amazon forest. The 3-D model scene was developed from airborne lidar data, and local measurements of leaf reflectance, aerosols, and PAR were used to model lAPAR under direct and diffuse illumination conditions. Simulated lAPAR under clear-sky and cloudy conditions was corrected for light saturation effects to estimate light utilization, the fraction of lAPAR available for photosynthesis. Although the fraction of incoming PAR absorbed by leaves was consistent throughout the year (0.80–0.82), light utilization varied seasonally (0.67–0.74), with minimum values during the Amazon dry season. Shadowing and light saturation effects moderated potential gains in forest productivity from increasing PAR during dry-season months when the diffuse fraction from clouds and aerosols was low. Comparisons between DART and other models highlighted the role of 3-D forest structure to account for seasonal changes in light utilization. Our findings highlight how directional illumination and forest 3-D structure combine to influence diurnal and seasonal variability in light utilization, independent of further changes in leaf area, leaf age, or environmental controls on canopy photosynthesis. Changing illumination geometry constitutes an alternative biophysical explanation for observed seasonality in Amazon forest productivity without changes in canopy phenology.

Prevalence and pattern of asthma exacerbation in children seen at the University of Nigeria Teaching Hospital, Enugu

Background: Acute exacerbation is a major cause of morbidity in asthmatic children. It can occur even in well controlled asthma. Aim: To determine the prevalence and pattern of acute exacerbation of asthma in children seen at the emergency room of the University of Nigeria Teaching Hospital (UNTH), Enugu. Materials and methods: This was a descriptive, cross sectional study in which consecutive children with acute exacerbation of asthma presenting to the Children Emergency Room (CHER) of UNTH, Enugu were recruited. Information from the history and examination were documented with a structured questionnaire completed by the attending doctor. Severity of their exacerbation was determined using the Global Initiative for Asthma (GINA) guidelines. The children were treated using the written management protocol used in CHER, UNTH, Enugu which was adapted from GINA guidelines. Results: There were a total of 114 presentations (episodes) of acute exacerbation asthma by 104 children within the study period with eight children having multiple episodes. This represented 6.5% of the overall number of emergency cases seen during the period. Nearly an equal number (ratio; 1: 1.04) of males and females were enrolled with the mean age of 7.9 ± 4.7 years. More children with asthma exacerbations were admitted during the rainy season months of May and June, while the dry season months of December and January recorded lower number of episodes. Most (86.0%) cases were mild to moderate exacerbations and 16 (15.3%) were severe. Three of the 22 (13.6%) children on controller medications were among the 16 that had severe exacerbation. No death was recorded during the period. Conclusion: The prevalence of asthma exacerbation is relatively high in our tropical environment and the pattern is similar to those of the developed countries in terms of age and sex distribution, however, the peak period of presentation differ in our environment. Keywords: Asthma, exacerbation, children, prevalence, pattern

Analysis of observed surface ozone in the dry season over Eastern Thailand during 1997–2012

This study analyzed observed surface ozone (O3) in the dry season over a long-term period of 1997–2012 for the eastern region of Thailand and incorporated several technical tools or methods in investigating different aspects of O3. The focus was the urbanized and industrialized coastal areas recently recognized as most O3-polluted areas. It was found that O3 is intensified most in the dry-season months when meteorological conditions are favorable to O3 development. The diurnal variations of O3 and its precursors show the general patterns of urban background. From observational O3 isopleth diagrams and morning ratios of non-methane volatile organic compounds (NMVOC) and nitrogen oxides (NOx), the chemical regime of O3 formation was identified as VOC-sensitive, and the degree of VOC sensitivity tends to increase over the years, suggesting emission control on VOC to be suitable for O3 management. Both total oxidant analysis and back-trajectory modeling (together with K-means clustering) indicate the potential role of regional transport or influence in enhancing surface O3 level over the study areas. A meteorological adjustment with generalized linear modeling was performed to statistically exclude meteorological effects on the variability of O3. Local air-mass recirculation factor was included in the modeling to support the coastal application. The derived trends in O3 based on the meteorological adjustment were found to be significantly positive using a Mann–Kendall test with block bootstrapping.

ESTRATÉGIAS FENOLÓGICAS REPRODUTIVAS DE Xylopia aromatica (LAM.) MART. (ANNONACEAE) EM ÁREA DE CERRADO

RESUMO Apesar dos esforços empreendidos nos últimos anos, os dados sobre a fenologia das espécies do Cerrado são fragmentários e mesmo X. aromatica sendo amplamente distribuída sua fenologia é desconhecida. Neste sentido, buscou-se avaliar sua fenologia reprodutiva em um fragmento de Cerrado no Município de Rio Verde e correlaciona-la com as variáveis climáticas. Marcou-se 20 indivíduos para serem observadas mensalmente as fenofases: botão, flor aberta, fruto imaturo e maduro. Para as análises utilizou-se o percentual de Fournier, método de presença/ausência e correlação de Spearman. A emissão de botões ocorreu de modo irregular e os mesmos estiveram presentes tanto no período seco quanto no chuvoso de modo a não se correlacionar com nenhuma das variáveis. A floração ocorreu de forma distribuída ao longo do estudo se correlacionando de modo negativo apenas com a umidade relativa. A frutificação ocorreu no período seco e na transição do período seco para o chuvoso, correlacionada negativamente com a precipitação e umidade. Os frutos amadureceram nos últimos meses da estação seca e primeiros da chuvosa, se correlacionando apenas com a umidade. O ciclo reprodutivo de X. aromatica não é influenciado fortemente pelas variáveis climáticas e o fato de se correlacionar negativamente com a precipitação e umidade sugere que a espécie foi adaptada de modo a otimizar a polinização e dispersão de frutos.

Intraspecific biogenic silica variations in the grass species Pennisetum pedicellatum along an evapotranspiration gradient in South Niger

Climate influences terrestrial Si and C cycles. To evaluate how drought influences Si dynamics in African savannahs we studied 12 sites along a climatic gradient of precipitation and drought-stress in South Niger. We analysed plant traits and Si (phytolith) content in 12 specimens of a drought adapted grass species (Pennisetum pedicellatum Trin.), and in surface soils. Phytolith/amorphous silica (ASi) was quantified by the 1%Na2CO3 (nc) digestion method, and the acid plus heavy-liquid extraction method (bz). Phytolith morphotypes were also analysed under the microscope. Our results show that with increasing drought-stress (decreasing AET/PET and precipitation, and increasing temperature), ASi in P. pedicellatum (ApSinc and ApSibz) increases, while ASi in soils (AsSibz) decreases. ApSinc shows higher correlation with precipitation of the wettest month (Pwet, r=−0.84, p<0.001), AET/PET (r=−0.73, p<0.01) and length of dry season (r=0.83, p<0.001) than with AsSibz (r=−0.59, p<0.05). Plant height increases with increasing precipitation (r=0.61, p<0.05). Leaf area is positively correlated with AsSibz (r=0.81, p<0.01). Bulliform phytoliths in P. pedicellatum growing under driest climate represent up to 12% of the leaf phytolith assemblage and just 2% in specimens sampled south of ∼13°N at more humid sites. Thus, the abundance of silicified bulliform cells is strongly negatively correlated with Pwet (r=−0.92, p<0.001) and AET/PET (r=−0.93, p<0.001). Other intra-specific variations, e.g. the length of bilobate phytoliths, are not observed along the climatic gradients documented here. We conclude that drought and evapotranspiration rates influence plant height and leaf size, increase Si uptake by the C4 grass P. pedicellatum, and favour silicification of the bulliform (motor) cells triggering leaf movements. In surface soils, greater phytolith accumulation is likely due to higher plant productivity and weaker soil erosion at humid sites.

Assessment of rainfall variability, rainwater harvesting potential and storage requirements in Odeda Local Government Area of Ogun State in South-western Nigeria

AbstractRainfall variability with periodicity of 5–6 years has been demonstrated for our study area and may be attributed to tropical and extra-tropical factors which operate during different months, seasons and years. Rainfall variability in terms of coefficient of variation ranges from 24 to 39% and 26 to 41% for the seasons and months. The mean increase of 1.63 mm/year and 1.37 mm/year experienced in the dry season months (November–April) and the wet season months (May–October), respectively, is insignificant from a water management perspective. Hoeffding’s D statistics revealed prevalence of non-monotonic trend in all the months and seasons. Recommended minimum and maximum storage capacity requirements for a six-member household to maximize rainwater harvesting are 1 and 6 m3, respectively. The rainwater harvesting potential for the area of study ranges between 18.16 and 27.45 m3 and 15.23 and 30.40 m3 based on the maximum error estimate and coefficient of variation methods. Domestic rainwater harvest...

Efecto de la suplementación con ensilado ("Festuca dolichophylla, Avena sativa y Vicia sativa") sobre la ganancia de peso y mortalidad en alpacas adultas ("Vicugna pacos")

This study was conducted in order to evaluate the effect of supplementation with silage ( Festuca dolichophylla , Avena sativa and Vicia sativa ) on weight gain and mortality in adult alpacas, during the months of dry season (June to August) in Huancavelica region. 300 female alpacas 3 and 4 years of age (physiological state: pregnant) were used, which were assigned to the following treatments: SP, grazing only PSE15, grazing plus supplementation of 1.5 kg of silage. Alpacas were supplemented once daily. In each alpaca they were recorded live weight at the beginning and end of the experiment. The weight gain was -0.02 y 2.05 kg for SP and PSE15 respectively (p <0.001) treatments. Mortality was 5.3% and 2.7% for SP and PSE15 respectively (p=0.073) treatments. It can be concluded under the conditions of this trial silage supplementation has effect on weight gain and maybe also on mortality in alpacas.

Feeding ecology and behavioral adjustments: flexibility of a small neotropical primate (Callithrix jacchus) to survive in a semiarid environment

Semiarid environments are known for climate extremes such as high temperatures, low humidity, irregular precipitations, and apparent resource scarcity. We aimed to investigate how a small neotropical primate (Callithrix jacchus; the common marmoset) manages to survive under the harsh conditions that a semiarid environment imposes. The study was carried out in a 400-ha area of Caatinga in the northeast of Brazil. During a 6-month period (3 months of dry season and 3 months of wet season), we collected data on the diet of 19 common marmosets (distributed in five groups) and estimated their behavioral time budget during both the dry and rainy seasons. Resting significantly increased during the dry season, while playing was more frequent during the wet season. No significant differences were detected regarding other behaviors. In relation to the diet, we recorded the consumption of prey items such as insects, spiders, and small vertebrates. We also observed the consumption of plant items, including prickly cladodes, which represents a previously undescribed food item for this species. Cladode exploitation required perceptual and motor skills to safely access the food resource, which is protected by sharp spines. Our findings show that common marmosets can survive under challenging conditions in part because of adjustments in their behavior and in part because of changes in their diet.

COMPARISON OF UNIVARIATE AND BIVARIATE APPROACHES TO MAP PRECIPITATION USING GEOSTATISTICS AND THE KALMAN FILTER

Measured rainfall data are very important in agriculture and environmental science. However, in many cases, the information gathered by existing rain gauges is insufficient for characterizing climatic variation within a study area. Thus, the use of interpolation techniques is necessary to predict values to unsampled sites. In this work, the performances of geostatistical algorithms, such as ordinary kriging and ordinary cokriging, and a proposed Kalman filter method were compared for mapping rainfall. The analysis was performed using both univariate and bivariate approaches. Natural terrain elevation was taken as the auxiliary variable for the bivariate case. The analysis was conducted for specific months of the dry and wet seasons in the Santiago River basin in Mexico. After comparison of the statistical errors, it was established that the geostatistical methods provided excellent results (especially cokriging) for the wet season months, with good correlation of 0.7 or above between rainfall and elevation, but not for the dry season months. Nevertheless, good results were achieved for the dry season months using the proposed Kalman filter methodology, due to the high normality and spatial dependence of the sample in this period.

Investigation of the Effect of Weather Conditions on Solar Energy in Rivers State University of Science and Technology, Port Harcourt, Nigeria

This study presents the effect of temperature, relative humidity, rainfall and evaporation on solar energy in Port Harcourt City, Nigeria. The data was recorded every 5 minutes daily and monthly, covering 2008 – 2014, in The Rivers State University of Science and Technology, Port Harcourt Meteorological Logging Unit. The MATLAB software used in the analysis of the data reveal a direct relationship between solar radiation and temperature and evaporation, and an inverse relationship with rainfall and relative humidity. The mean atmospheric temperature is 26.02oC, while solar energy varies between 47.07 mJm-2 month-1 and 113.99 mJm-2month-1 with a mean of 87.87 mJm-2month-1. During the rainy season (April – September), the mean monthly solar energy is 86.69mJm-2month-1, while in the dry season (October – March), the mean is 89.05mJm-2month-1. The amount of evaporation per temperature ranges from 2.92 mm/oC to 4.47 mm/oC with a mean annual of 3.57 mm/oC. In the rainy season, this value varies from 2.79 mm/oC to 3.79 mm/oC. In the dry season months, the variation is from 3.12 mm/oC to 4.47 mm/oC. The rainfall-to-evaporation ratio of 5.71 in rainy month demonstrates that about the amount of rainfall is recorded for the amount of water evaporated. This correlates with the fact that humidity is high. The results of this work could be used in the design and construction of solar energy technologies to provide energy. Moreover, the results could also provide input for climate risk information, local and national planning and decision-making for sustainable development in the areas of agriculture, aviation, health, and weather forecasting.