scholarly journals ALGUNOS ASPECTOS SOBRE LA TEMPERATURA DE HOJAS PERTENECIENTES A PLANTAS DE LA REGIÓN XEROFÍTICA DE SANTA MARTA (COLOMBIA)

2016 ◽  
Vol 5 ◽  
Author(s):  
Reinhard Schnetter
Keyword(s):  
Water Supply ◽  
Plant Species ◽  
High Temperatures ◽  
Dry Season ◽  
Wet Season ◽  
Favorable Conditions ◽  
Very High

Leaf temperatures of several plant species of the xerophytic vegetation near Santa Marta (Colombia) were studied during the dry and the wet season. The leaves of species growing in a cactus thorn scrub reached very high temperatures, especially in the dry season, while leaf temperatures of plants in the area of a disappeared semi-deciduous seasonal forest were lower because of more favorable conditions of water supply and microclimate.

Diet determination of cattle grazing in the Sanyati communal areas in Zimbabwe

2006 ◽  
Vol 34 ◽  
pp. 35-40
Author(s):  
Hanne H. Hansen ◽  
Jørgen Madsen
Keyword(s):  
Plant Species ◽  
Cattle Grazing ◽  
Dry Season ◽  
Particle Identification ◽  
Grass Species ◽  
Wet Season ◽  
Communal Area ◽  
Communal Areas

SummaryThe diet of cattle grazing in the Sanyati communal area, Zimbabwe was determined using plant particle identification from faeces from intact animals, and faeces and oesophageal extrusa from fistulated animals. A total of 130 plant genus, species and types were identified. The twenty most frequently occurring species in the samples comprised between 76 and 90% of the identifiable diet. The most frequent grass species were more than half of the identified diet in the dry season while they were half or less of the identified diet in the wet season. There were more plant species identified in the wet season than in the dry season. Significant differences were found when comparing the plant species identified in faeces to those in oesophageal extrusa from fistulated animals. This may be due to incomplete recovery of ingesta in the bags, or to the loss of identifiable particles in the faeces when compared to oesophageal extrusa because of digestibility. More research is needed to validate the use of oesophageal extrusa for diet botanical determination.

Seasonal Variation in Bee-Plant Interactions in an Inselberg in the Atlantic Forest in Southeastern Brazil

Sociobiology ◽  
2018 ◽  
Vol 65 (4) ◽  
pp. 612 ◽  
Author(s):  
Marcelita França Marques ◽  
Mariana Scaramussa Deprá ◽  
Maria Cristina Gaglianone
Keyword(s):  
Plant Species ◽  
Atlantic Forest ◽  
Temporal Dynamics ◽  
Interaction Network ◽  
Dry Season ◽  
Floral Resources ◽  
Southeastern Brazil ◽  
Plant Interactions ◽  
Wet Season ◽  
Bee Plant

Studies on bee-plant interactions are relevant to the understanding of temporal patterns in neotropical communities. In isolated habitats such as inselbergs little is yet known about the temporal dynamics in the availability of fl oral resources and interacting bee. In the present study, the objective is to verify the eff ect of seasonality on the bee-plant interaction in an Atlantic Forest inselberg in southeastern Brazil. The bees were sampled monthly in the dry (April/2008-September/2008) and wet seasons (October/2008-March/2009) using an entomological net. A total of 322 bees of 33 species were captured on fl owers of 34 species of plants during the year. Bees richness was similar between seasons (22 species in the wet season and 21 in the dry season), but abundance was higher in the wet season (60% of individuals) and higher diversity occurred in the dry season. Augochloropsis sp1 were the most abundant species and visited the largest number of plant species at each season. In the interaction network, plants with the highest degree were distinct between the seasons. The number of possible interactions was higher in the dry season compared to the wet season and connectance was similar; nestedness however varied between the seasons. The composition of plant and bees species was distinct between the seasons, as well as the interactions between them, mainly due to the alteration in the composition of the plant species and the change in the choice of the bees for the floral resources between the seasons.

Patterns and correlates of interspecific variation in foliar insect herbivory and pathogen attack in Brazilian cerrado

2001 ◽  
Vol 17 (1) ◽  
pp. 127-148 ◽  
Author(s):  
ROBERT J. MARQUIS ◽  
IVONE R. DINIZ ◽  
HELENA C. MORAIS
Keyword(s):  
Plant Species ◽  
Interspecific Variation ◽  
Dry Season ◽  
Mature Leaf ◽  
Insect Damage ◽  
Wet Season ◽  
Leaf Production ◽  
Leaf Toughness ◽  
Interspecific Differences ◽  
Pathogen Attack

Patterns of insect herbivore and leaf pathogen attack are described for 25 plant species (10 trees, 10 shrubs and five herbs) at a Brazilian savanna (cerrado) site. Plant and leaf traits were correlated with interspecific variation in attack by herbivores and pathogens in order to account for differences among plant species. Across all species, pathogen damage was 1.5 times higher than insect damage (17.3% vs. 6.8%, respectively). Most insect damage occurred to young leaves while they were expanding (end of the dry season). In contrast, pathogen attack was low on young expanding leaves at the end of the dry season, increased as those leaves matured in the wet season, but continued to increase through the next dry season. Protein-binding capacity was negatively associated with interspecific differences in insect damage to mature leaves. Protein availability and plant height were positive predictors of pathogen attack among plant species, while leaf expansion rate was a significant negative predictor. Interspecific differences in leaf phenology had little effect on the amount of damage caused by either insects or pathogens. However, new leaves produced during the wet season suffered less insect damage than leaves produced during the dry season, the time of greatest leaf production. Timing of young leaf production affected pathogen attack but the season of escape depended on plant species. In contrast, there was no evidence for escape in space as common species were less likely to suffer high pathogen attack than rare species. New and mature leaf toughness, and time for a leaf to reach full expansion all increased from herbs to shrub to trees, while mature leaf nitrogen decreased in that order.

scholarly journals Vertical Arthropod Dynamics across Organic Matter Fractions in Relation to Microclimate and Plant Phenology

2020 ◽  
Author(s):  
María F. Barberena-Arias ◽  
Elvira Cuevas
Keyword(s):  
Organic Matter ◽  
Species Composition ◽  
Plant Species ◽  
Dry Season ◽  
Temperature Pattern ◽  
Wet Season ◽  
Key Factor ◽  
Organic Matter Fractions ◽  
One Year ◽  
Arthropod Abundance

Plant diversity is a key factor influencing belowground dynamics including microclimate and decomposer arthropod communities. This study addresses the effect of individual plant species on belowground arthropods by focusing on seasonal variations in precipitation, temperature and arthropods along the vertical organic matter profile. In the Guanica Dry Forest, Puerto Rico, microclimate was described and 5 plant species and 10 trees/species were selected. Under each tree, for one year, temperature was measured and samples collected along the organic matter fractions. Collected arthropods were standardized to ind/m2, identified to Order/Family and assigned to morphotypes. The annual temperature pattern was similar for all species and OM fractions. Arthropod abundance was similar among plant species and higher in humus than in litter fractions. Richness and species composition were different among plant species and OM fractions. All plant species and OM fractions showed low arthropod abundance and richness, and similar arthropod species composition in the dry season, while in the wet season abundance and richness were higher and species composition varied across plant species and OM fractions. These data suggest that arthropods form specific assemblages under plant species and stages of decomposition that, during the dry season, represent a subgroup adapted to extreme environmental conditions.

scholarly journals Measurements of soil respiration and simple models dependent on moisture and temperature for an Amazonian southwest tropical forest

2009 ◽  
Vol 6 (3) ◽  
pp. 6147-6177 ◽  
Author(s):  
F. B. Zanchi ◽  
H. R. da Rocha ◽  
H. C. de Freitas ◽  
B. Kruijt ◽  
M. J. Waterloo ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Field Measurements ◽  
Dry Season ◽  
Wet Season ◽  
Hourly Data ◽  
Fresh Litter ◽  
Favorable Conditions

Abstract. Soil respiration plays a significant role in the carbon cycle of Amazonian tropical forests, although in situ measurements have only been poorly reported and the dependence of soil moisture and soil temperature also weakly understood. This work investigates the temporal variability of soil respiration using field measurements, which also included soil moisture, soil temperature and litterfall, from April 2003 to January 2004, in a southwest Brazilian tropical rainforest near Ji-Paraná, Rondônia. The experimental design deployed five automatic (static, semi-opened) soil chambers connected to an infra-red CO2 gas analyzer. The mean half-hourly soil respiration showed a large scattering from 0.6 to 18.9 μmol CO2 m−2 s−1 and the average was 8.0±3.4 μmol CO2 m−2 s−1. Soil respiration varied seasonally, being lower in the dry season and higher in the wet season, which generally responded positively to the variation of soil moisture and temperature year round. The peak was reached in the dry-to-wet season transition (September), this coincided with increasing sunlight, evapotranspiration and ecosystem productivity. Litterfall processes contributed to meet very favorable conditions for biomass decomposition in early wet season, especially the fresh litter on the forest floor accumulated during the dry season. We attempted to fit three models with the data: the exponential Q10 model, the Reichstein model, and the log-soil moisture model. The models do not contradict the scattering of observations, but poorly explain the variance of the half-hourly data, which is improved when the lag-time days averaging is longer. The observations suggested an optimum range of soil moisture, between 0.115

Enhancing food security in semi-arid eastern Indonesia through permanent raised-bed cropping: a review

1999 ◽  
Vol 39 (8) ◽  
pp. 1035 ◽  
Author(s):  
D. E. Van Cooten ◽  
A. K. Borrell
Keyword(s):  
Water Supply ◽  
Food Production ◽  
Crop Production ◽  
Ground Cover ◽  
Dry Season ◽  
Wet Season ◽  
Additional Food ◽  
Eastern Indonesia ◽  
Raised Bed ◽  
Semi Arid

Summary. Much of south-eastern Indonesia is mountainous and characterised by a semi-arid tropical environment. Soil erosion is a significant environmental problem facing the region, affecting both productivity of the land and water quality. The challenge for the region is to secure year-round food production in such a fragile environment. More than 90% of rain falls in a distinct wet season between November and April. Therefore, cropping in this region is dependent on matching crop growth with water supply. In particular, crop production depends on the efficient use of rainfall during the wet season, including avoidance of waterlogging, and efficient use of stored soil water during the dry season. This paper summarises the results of a series of experiments undertaken in West Timor, Indonesia, between 1993 and 1999 aimed at developing a raised-bed cropping system. The objective of these studies was to better utilise the more fertile alluvial soils that are often susceptible to waterlogging during the wet season, allowing a range of crops to be grown in addition to rice. Raised beds of height 0.2 m and width 1.5 m were constructed either manually or with an 8.5 hp two-wheeled hand tractor. A range of crops including soybeans, sorghum, maize, pigeon pea, yam bean and cassava were successfully grown on raised beds in the wet season in addition to rice, indicating that raised-bed technology overcomes the constraints of waterlogging in the wet season. Soybeans grew particularly well on raised beds, with December-sown crops producing almost twice the yield of January-sown crops (2.6 v. 1.4 t/ha). For rice and soybeans, early sown crops were better able to match growth with water supply, thereby avoiding end-of-season drought. Early sowing and harvesting of wet season crops enables a drought-resistant crop such as sorghum to be planted in lateMarch or early April, utilising the stored soil moisture for grain production and also maintaining ground cover in the dry season. It is argued that cropping systems based on permanent raised beds can reduce erosion in 2 ways. First, raised beds are a permanent structure and, with the inter-cropping and relay-cropping proposed, crops can provide all-year ground cover in lowland areas. Second, if sufficient food and cash crops are grown on raised beds to meet the basic needs of subsistence farmers, then upland cropping on steep slopes can be replaced by a variety of tree species, providing additional food, fodder, firewood and medicines. Together, these strategies have the capacity to enhance food production and security in the semi-arid areas of eastern Indonesia.

scholarly journals Distributional Coefficients and Enrichment Studies of Potentially Toxic Heavy Metals in Soils Around Itakpe Iron-Ore Mine, North Central Nigeria

2016 ◽  
Vol 6 (1) ◽  
pp. 85
Author(s):  
Eneojo Godwin Ameh ◽  
Mofoloronsho Samuel Kolawole ◽  
Sunday Ojochogwu Idakwo ◽  
Caroline Ojone Ameh ◽  
Ebo GabrielImeokparia
Keyword(s):  
Heavy Metals ◽  
Iron Ore ◽  
Pollution Index ◽  
Dry Season ◽  
Soil Samples ◽  
Background Concentration ◽  
Wet Season ◽  
Environmental Indices ◽  
Hazard Level ◽  
Very High

Soil samples were collected randomly but uniformly distributed around Itakpe iron-ore mines in both dry and wet seasons. Surface soils were collected from 0cm to 10cm using stainless steel augers and located using Global Positioning System (GPS). Soil samples were air-dried, sieved through 500um mesh and 1.0g digested, evaporated and analysed using Atomic Absorption Spectrometer (AAS).Five (5) geo-environmental indices were used to quantitatively evaluate the degree of soil contamination due to iron ore mining. The anthropogenic factor (AF) for both seasons revealed that all heavy metals have greater than 50% AF except for Cd in the dry season. The geo accumulation index (Igeo) for both seasons showed background concentration to unpolluted for Cu and Zn while Fe, Ni, Cdand Pb recorded moderately to very highly polluted. The pollution index (Eri), showed tiny hazard level for all the heavy metals in dry season and in wet season, Cd and Ni recorded strong hazard level while tiny hazard level were observed for Cu and Pb. The ecological pollution index for the area is strong (RI=323.25). Dry and wet season enrichment factor (EF) revealed background concentration for all the heavy metals except Fe with EF> 40 (extremely high enrichment). While contamination factor (CF) was very high for Fe in both seasons, Cu and Ni recorded considerable to very high contamination in dry season. The wet season also revealed considerable contamination for Ni and Cd; moderate to considerable contamination for Cu, Zn and Pb. The sites in both seasons have experienced various degrees of deterioration but more significant in wet season. Based on these indices, the soils around Itakpe iron-ore area has suffered significant degrees of contaminations with respect to Fe, Ni, Cd and Pb.

scholarly journals Impact of Flow Variation on Hydropower Projects in Budhigandaki River Basin of Nepal

2021 ◽  
Vol 26 (1) ◽  
pp. 89-98
Author(s):  
Suresh Marahatta ◽  
Laxmi Prasad Devkota ◽  
Deepak Aryal
Keyword(s):  
Annual Variation ◽  
Energy Generation ◽  
Dry Season ◽  
Wet Season ◽  
Flow Variation ◽  
Small Uncertainty ◽  
Average Loss ◽  
The Impact ◽  
Very High

Daily flow data from 1964 to 2015 of Budhigandaki River at Arughat were analyzed to assess the impact of flow variation at different time scales to the run of the river (RoR) type of hydropower projects. The data show very high inter-annual variation in daily, monthly and seasonal flows. The long term annual average flow at Arughat was 160 m3/s and varies from 120 to 210 m3/s. The long-term averages of loss in flow for both dry and wet seasons based on daily flows for three design discharges (Q90, Q60 and Q40) were found to be respectively -0.72, -1.76 and -1.54 m3/s for dry season and 0.0, -0.27 and -2.26 m3/s for wet season.  Although long-term average loss is small, uncertainty increases with the increase in design discharge. The long-term dry season power loss is about 3 % for the RoR projects of the basin however, its annual variation is large. There is a probability of losing the quantum of energy generation by nearly 40% in some years and gaining by about 30 % in some other years in dry season. The impact of flow variation on power production was negative in both dry and wet seasons for RoR projects of Budhigandaki basin. This study concludes that uncertainty arising from daily flow variation should be assessed while estimating energy generation in hydropower projects. Intra-annual flow variation is, thus, to be taken into consideration while calculating the power generated by the RoR plants; and it should be reflected in power purchase agreement.

scholarly journals Predictive modeling of floristic components using soil variables in seasonal lacustrine wetlands

2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Ita RE ◽  
Ogbemudia FO ◽  
Udo NS
Keyword(s):  
Environmental Factors ◽  
Mathematical Models ◽  
Plant Species ◽  
Basal Area ◽  
Plant Ecology ◽  
Dry Season ◽  
Wet Season ◽  
Exchangeable Acidity ◽  
Soil Variables ◽  
Crown Cover

The overlap between vegetation and environmental factors in wetlands has always been a key area in plant ecology. Studying vegetation components in wetland without allusion to the environmental factors governing their distribution is inconclusive. To this end, mathematical models were applied to predict floristic components using soil variables in seasonal lacustrine wetlands. A quadrat size of 5m×5m was used to systematically sample the vegetation for density, frequency, height, basal area and crown cover. In each quadrat, soil samples were obtained at different rooting depths (0 -15cm and 15–30cm). Results obtained showed variations in the floristic composition in the wetlands seasonally. Rural wetland had seventeen (17) plant species during the dry season and fourteen (14) plant species during the wet season while urban wetland had eleven (11) plant species in the dry season and thirteen plant species (13) in the wet season. Variations in density, height, frequency, basal area and crown cover occurred in the wetlands. The physicochemical properties of the soil in these wetlands varied seasonally. A prediction model using stepwise multiple regression analysis revealed the vegetation and species responses to the environment on the basis of soil variables and also showed their relationship with each other. It also showed the various predictors (soil properties) of the vegetation components such as density (exchangeable acidity, sand, pH, Na, Zn, Cd, Ca and total nitrogen), height (base saturation, Ni and sand), crown cover (exchangeable acidity, clay and electrical conductivity) and basal area (exchangeable acidity). In summary, it is established that using mathematical models, environmental variables (soils) can serve as good predictors of vegetation components in wetlands by elucidating the soil-vegetation interrelationships.

scholarly journals Integrated Characterization of Toxicity Distribution of Selected Heavy Metals in Stream Sediments Around Itakpe Iron Ore Mines, North Central Nigeria

2016 ◽  
Vol 6 (1) ◽  
pp. 109
Author(s):  
Eneojo Godwin Ameh ◽  
Ojochogwu Sunday Idakwo ◽  
Ojone Caroline Ameh ◽  
Omojo Mercy Lekdukum
Keyword(s):  
Heavy Metals ◽  
Enrichment Factor ◽  
Contamination Factor ◽  
Stream Sediments ◽  
Dry Season ◽  
Middle Level ◽  
Wet Season ◽  
Hazard Level ◽  
Very High

The results of the analysis were subjected to five (5) indices: contamination factor (CF); Ecological risk factor (Eri); Enrichment factor (EF); index of geo-accumulation (Igeo) and anthropogenic factor (AF). The CF results showed that the River PomPom dry and wet season sediments were collected in February and July respectively from 0cm to 10cm depth. Stainless steel spoon was used to collect the samples. The sediment samples were packaged, labeled and refrigerated for onward transportation to the laboratory. All samples were oven-dried (50oC) for about 24 hours, sieved through -80 mesh. About 1.0g of each sample was digested, filtered and the filtrates were ready for heavy metal analysis using Atomic sediments were most contaminated with Fe in both seasons, least contaminated with Cd at dry season and Zn in wet season. The Eri factor revealed pollution hazard level of middle during wet season and tiny in dry season. Pb and Ni showed strong and middle hazard level during wet season and Cu revealed middle level during dry season. The enrichment factor indicated extremely enriched for Fe in all locations in both seasons while most heavy metals showed depletion to minimal enrichment. The Igeo for both seasons showed that Fe was moderately to highly polluted in all locations. During dry season, other heavy metals showed moderately to unpolluted while in wet season Cd, Ni and Pb indicated moderately to very highly polluted. In both seasons, the % AF was very high for Fe, Cu, Pb. The AF% was very high for Ni and Cd in wet season. All sites in both seasons have experienced deterioration but more in the wet season. From these indices, the stream sediments have been significantly contaminated with Fe, Ni, Pb and Ni in most locations in both seasons.

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