Phenological changes in a Sumatran rain forest

1986 ◽  
Vol 2 (4) ◽  
pp. 327-347 ◽  
Author(s):  
C. P. Van Schaik
Keyword(s):  
Leaf Litter ◽  
Rain Forest ◽  
Seasonal Pattern ◽  
Dry Season ◽  
Wet Season ◽  
Phenological Changes ◽  
Young Leaves ◽  
Fig Trees ◽  
One Year ◽  
Made In

ABSTRACTPhenological observations were made in a Sumatran rain forest during three years (1980–1982). Phenological changes followed a consistent seasonal pattern. The abundance of young leaves and the fall of leaf litter peaked between December and February (first dry season); flowers were most abundant between January and April (first dry and first wet sea son), and ripe fruits in July-August (the second dry season). The fruit of strangling fig trees showed peaks in April and October, both wet season months. Within the study area there was variation in both the phase and the amplitude of the phenological cycles. One year, 1981, displayed mast flowering and fruiting. The observations indicate that the conditions for production were better during the mast year, a finding that facilitates our understanding of the evolution of mast fruiting.

Effect of the red land crab (Gecarcinus lateralis) on leaf litter in a tropical dry forest in Veracruz, Mexico

1993 ◽  
Vol 9 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Martin Kellman ◽  
Bianca Delfosse
Keyword(s):  
Leaf Litter ◽  
Seasonal Pattern ◽  
Coastal Dunes ◽  
Dry Season ◽  
Dry Forest ◽  
Wet Season ◽  
Nutrient Pools ◽  
Land Crab ◽  
Litter Biomass ◽  
Gecarcinus Lateralis

ABSTRACTThe effect of the red land crab (Gecarcinus lateralis) on leaf litter biomass and nutrient transformation was investigated in a semi-deciduous tropical forest on coastal dunes using access and exclusion plots observed for six months. Crabs were in burrows during drought, but began foraging immediately after rainfall. Crabs accelerated litter disappearance significantly during the wet season at one site located beneath Brosimum alicastrum, but had no effect beneath a nearby Enterolobium cyclocarpum. The difference is tentatively attributed to small leaflet size in the latter species which crabs were unable to handle and consume. At both sites, litter in exdosures had approximately doubled by the end of the ensuing dry season. At the Brosimum site it is attributed to sporadic crab detritivory occurring after dry seasonal rains. At the Enterolobium site it is attributed to preferential retention of litter in the cxclosures during strong dry season winds. The nutrient content of litter exposed to, or protected from, crabs was not significantly different at either site and differences in litter nutrient pools reflected differences in litter biomass. Accelerated nutrient mineralization due to crab detritivory was concentrated early in the wet season before leaching began from the soils, and it is suggested that this altered seasonal pattern of mineralization may reduce the loss of nutrients from the site in percolating water.

scholarly journals Branch elongation and diameter growth were temporally dissociatedin "cerrado" tree species

Hoehnea ◽  
2009 ◽  
Vol 36 (3) ◽  
pp. 437-444 ◽  
Author(s):  
Davi Rodrigo Rossatto
Keyword(s):  
Water Status ◽  
Carbon Assimilation ◽  
Dry Season ◽  
Diameter Growth ◽  
Wet Season ◽  
Dry Period ◽  
Central Brazil ◽  
Branch Growth ◽  
Tree Community ◽  
One Year

Here is a communicating about time differences between branch and diameter growth in a tree community of ten species in Neotropical savanna ("cerrado") of Central Brazil. This work was conducted to study branch expansion and diameter growth in a period of one year between 2006 and 2007. Branch growth had begin in middle dry season and had the peak occurrence during the dry period in September, while diameter growth had begin in late dry season and peaked in the middle of wet season in December. The majority of species followed the same pattern. Branch growth did not have relation with rainfall, while diameter growth had a clear and positive relation with rainfall records. These results suggested that branch growth was not depend on rainfall but only on water status recover, while diameter growth probably depends strongly on water and to carbon assimilation that occurs after branch and leaf expansion.

scholarly journals On the epidemiology of helminth parasites in Hangul Deer Cervus hanglu hanglu (Mammalia: Artiodactyla: Cervidae) of Dachigam National Park, India

2021 ◽  
Vol 13 (1) ◽  
pp. 17517-17520
Author(s):  
Naziya Khurshid ◽  
Hidayatullah Tak ◽  
Ruqeya Nazir ◽  
Kulsum Ahmad Bhat ◽  
Muniza Manzoor
Keyword(s):  
Risk Factors ◽  
National Park ◽  
Helminth Infection ◽  
Dry Season ◽  
Helminth Parasites ◽  
Wet Season ◽  
Factors Associated ◽  
Dictyocaulus Viviparus ◽  
Dachigam National Park ◽  
One Year

A one-year study conducted to ascertain the prevalence and risk factors associated with helminth infection in Hangul Deer Cervus hanglu hanglu at Dachigam National Park revealed that 40.45% (89 of 220 samples) were infected with four helminth species including Heamonchus contortus, Trichuris ovis, Dictyocaulus viviparus, and Moneizia expansa.  The study signified that the infection was more prevalent during the dry season (summer and autumn) as compared to the wet season (winter and spring).  The overall prevalence of Heamonchus contortus was the highest (23.18%) followed by Trichuris ovis (8.18%), followed by Dictyocaulus viviparus (5.45%), and Moneizia expansa (3.63%).  The present study should be of importance in conserving the erstwhile state animal, listed as Critically Engendered in 2017 by IUCN.

scholarly journals Multi-year statistical and modelling analysis of submicrometer aerosol number size distributions at a rain forest site in Amazonia

2018 ◽  
Author(s):  
Luciana Varanda Rizzo ◽  
Pontus Roldin ◽  
Joel Brito ◽  
John Backman ◽  
Erik Swietlicki ◽  
...  
Keyword(s):  
Particle Size ◽  
Rain Forest ◽  
Amazon Basin ◽  
Particle Number ◽  
Dry Season ◽  
Forest Site ◽  
Size Distributions ◽  
Wet Season ◽  
Accumulation Mode ◽  
Aitken Mode

Abstract. The Amazon Basin is a unique region to study atmospheric aerosols, given their relevance for the regional hydrological cycle and large uncertainty of their sources. Multi-year datasets are crucial when contrasting periods of natural conditions and periods influenced by anthropogenic emissions. In the wet season, biogenic sources and processes prevail, and the Amazonian atmospheric composition resembles pre-industrial conditions. In the dry season, the Basin is influenced by widespread biomass burning emissions. This work reports multi-year observations of high time resolution submicrometer (10–600 nm) particle number size distributions at a rain forest site in Amazonia (TT34 tower, 60 km NW from Manaus city), between years 2008–2010 and 2012–2014. Median particle number concentration was 403 cm−3 in the wet season and 1254 cm−3 in the dry season. The Aitken mode (~ 30–100 nm in diameter) was prominent during the wet season, while accumulation mode (~ 100–600 nm in diameter) dominated the particle size spectra during the dry season. Cluster analysis identified groups of aerosol number size distribution influenced by convective downdrafts, nucleation events and fresh biomass burning emissions. New particle formation and subsequent growth was rarely observed during the 749 days of observations, similar to previous observations in the Amazon Basin. A stationary 1D column model (ADCHEM – Aerosol Dynamics, gas and particle phase CHEMistry and radiative transfer model) was used to assess importance of processes behind the observed diurnal particle size distribution trends. Three major particle source types are required in the model to reproduce the observations: (i) a surface source of particles in the evening, possibly related to primary biological emissions (ii) entrainment of accumulation mode aerosols in the morning, and (iii) convective downdrafts transporting Aitken mode particles into the boundary layer mostly during the afternoon. The latter process has the largest influence on the modelled particle number size distributions. However, convective downdrafts are often associated with rain and thus act both as a source of Aitken mode particles, and as a sink of accumulation mode particles, causing a net reduction in the median total particle number concentrations in the surface layer. Our study shows that the combination of the three mentioned particle sources are essential to sustain particle number concentrations in Amazonia.

scholarly journals Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

2007 ◽  
Vol 7 (20) ◽  
pp. 5415-5435 ◽  
Author(s):  
U. Rummel ◽  
C. Ammann ◽  
G. A. Kirkman ◽  
M. A. L. Moura ◽  
T. Foken ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Rain Forest ◽  
Deposition Velocity ◽  
Dry Season ◽  
Stomatal Aperture ◽  
Specific Humidity ◽  
Deposition Flux ◽  
Diel Variation ◽  
Wet Season ◽  
Ozone Deposition

Abstract. Within the project EUropean Studies on Trace gases and Atmospheric CHemistry as a contribution to Large-scale Biosphere-atmosphere experiment in Amazonia (LBA-EUSTACH), we performed tower-based eddy covariance measurements of O3 flux above an Amazonian primary rain forest at the end of the wet and dry season. Ozone deposition revealed distinct seasonal differences in the magnitude and diel variation. In the wet season, the rain forest was an effective O3 sink with a mean daytime (midday) maximum deposition velocity of 2.3 cm s−1, and a corresponding O3 flux of −11 nmol m−2 s−1. At the end of the dry season, the ozone mixing ratio was about four times higher (up to maximum values of 80 ppb) than in the wet season, as a consequence of strong regional biomass burning activity. However, the typical maximum daytime deposition flux was very similar to the wet season. This results from a strong limitation of daytime O3 deposition due to reduced plant stomatal aperture as a response to large values of the specific humidity deficit. As a result, the average midday deposition velocity in the dry burning season was only 0.5 cm s−1. The large diel ozone variation caused large canopy storage effects that masked the true diel variation of ozone deposition mechanisms in the measured eddy covariance flux, and for which corrections had to be made. In general, stomatal aperture was sufficient to explain the largest part of daytime ozone deposition. However, during nighttime, chemical reaction with nitrogen monoxide (NO) was found to contribute substantially to the O3 sink in the rain forest canopy. Further contributions were from non-stomatal plant uptake and other processes that could not be clearly identified. Measurements, made simultaneously on a 22 years old cattle pasture enabled the spatially and temporally direct comparison of O3 dry deposition values from this site with typical vegetation cover of deforested land in southwest Amazonia to the results from the primary rain forest. The mean ozone deposition to the pasture was found to be systematically lower than that to the forest by 30% in the wet and 18% in the dry season.

On-farm performance of Bunaji (White Fulani) cattle 1. Herd structures and cattle disposal

1993 ◽  
Vol 57 (2) ◽  
pp. 199-209 ◽  
Author(s):  
J. E. O. Rege ◽  
R. R. von Kaufmann ◽  
R. I. Mani
Keyword(s):  
Seasonal Pattern ◽  
Herd Size ◽  
Dry Season ◽  
Adult Males ◽  
Wet Season ◽  
Social Functions ◽  
Adult Females ◽  
Arable Farming ◽  
Herd Structure ◽  
Milk Market

AbstractA study urns conducted to examine herd structures and cattle disposal patterns of Bunaji herds kept under traditional management at four locations in the subhumid zone of Nigeria. Sale for meat was the single most important disposal reason, accounting for proportionately 0·55 of all disposals. Mean age of cattle sold for meat was 8 years but the age range was wide: animals as old as 17·4 years were involved in such sales. Male animals were sold at a younger age (6·2 years) than females (9·3 years). Sale of calves was an important exit avenue for rural herds with less access to milk market. Calves were sold at a mean age of 1·1 years and male calves accounted for a larger proportion (0·62) of such sales. Animal sales were highest in the early dry season and lowest in the early wet season. The predominantly arable farming location, Ganawuri, had the highest frequency of animal sales and lowest frequency of exits for ‘social functions’ (exchanges, transfers and gifts). Animal transfers, gifts and exchanges were important disposal routes in the traditionally pastoral communities, especially in locations with good grazing (e.g. Abet). Exits involving exchanges, transfers and gifts were more frequent during the dry season and least frequent in the wet season. An average herd had 77 head of cattle composed proportionately of 0·54 adult females (>3 years), 0·13 adult males (>3 years), 0·08 young bulls (1 to 3 years), 0·13 heifers (1 to 3 years) and 0·11 calves (0 to 1 year). There was a tendency toward smaller herds in later years (97 in 1980 to 51 in 1989) and a decrease in the ratio of adult females to males (from 6:1 in 1980 to 3:1 in 1989). Substantial between-location differences existed in herd size ami herd structure, ranging from the ‘beef orientation’ of the arable Ganawuri with a high proportion of immatures and calves, to the pastoral situation in Abet and Kurmin Biri with high proportion of adult animals. The proportions of adults were lowest in the early dry season, reflecting seasonal pattern in disposal and calving. The pattern in disposal reasons over time indicated a decrease in the proportion of animals exiting herds through exchanges, transfers and gifts and signified a possible shift from tradition, probably a response to population pressures and emergence of cash economies.

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 Influence of Temperature and Relative Humidity on Air Pollution in Addis Ababa, Ethiopia

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Endeshaw Lake
Keyword(s):  
Relative Humidity ◽  
Negative Correlation ◽  
Addis Ababa ◽  
Dry Season ◽  
Clear Correlation ◽  
Wet Season ◽  
Co Concentration ◽  
Reduction Of Nox ◽  
One Year ◽  
Atmospheric Variables

In this paper we access the effects of two atmospheric variables (temperature and relative humidity) on two important pollutants in the atmosphere (Nitrogen oxides (NOx) and carbon monoxide (CO)) by using one year (2016) data of Addis Ababa. Temperature has impact on atmospheric mixing and cause for the reduction of NOx as temperature increases. There are positive correlation between temperature and CO concentration from January to April with (R2 = 0.69), negative correlation from May to August with (R2 = 0.92) and no correlation for the remaining months. NOx and CO have moderate positive and negative correlation with relative humidity during the months January-April (R2 = 0.294 for NOx and R2 = 0291 for CO) and in the months May-August are R2 = 0.97 and R2 = 0.15 for NOx and CO respectively. But there are no clear correlation between the NOx and CO with relative humidity from September-December. NOx concentrations during wet season was almost about twice that of the dry season, but no such difference was observed in the case of CO. The seasonal average air temperature in wet season is relatively lower than dry season. NOx exhibited positive and CO negative seasonal correlations with relative humidity.

scholarly journals Epidemiological studies of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

2006 ◽  
Vol 73 (3) ◽  
Author(s):  
D.M. Pfukenyi ◽  
S. Mukaratirwa ◽  
A.L. Willingham ◽  
J. Monrad
Keyword(s):  
Intermediate Host ◽  
Climatic Factors ◽  
Seasonal Pattern ◽  
Chemical Properties ◽  
Dry Season ◽  
Wet Season ◽  
Adult Cattle ◽  
Host Snail ◽  
Faecal Samples ◽  
Hot Dry Season

During the period between January 1999 and December 2000, the distribution and seasonal patterns of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe were determined through monthly coprological examination. Faecal samples of cattle were collected from 12 and nine dipping sites in the highveld and lowveld communal grazing areas, respectively. Patterns of distribution and seasonal fluctuations of the intermediate host-snail populations and the climatic factors influencing the distribution were also determined at monthly intervals from November 1998 to October 2000, a period of 24 months, in six dams and six streams in the highveld and nine dams in the lowveld communal grazing areas. Monthly, each site was sampled for relative snail density, the vegetation cover and type, and physical and chemical properties of the water. Mean monthly rainfall and temperature were recorded. Snails collected at the same time were individually examined for shedding of cercariae of S. mattheei and Schistosoma haematobium. A total of 16 264 (5 418 calves, 5 461 weaners and 5 385 adults) faecal samples were collected during the entire period of study and 734 (4.5 %) were positive for S. mattheei eggs. Significantly higher prevalences were found in the highveld compared to the lowveld (P < 0.001), calves compared to adult cattle (P < 0.01) and the wet season compared to the dry season (P < 0.01). Faecal egg output peaked from October/ November to March / April for both years of the study. Bulinus globosus, the snail intermediate host of S. mattheei was recorded from the study sites with the highveld having a significantly higher abundance of the snails than the lowveld (P < 0.01). Monthly densities of B. globosus did not show a clearcut pattern although there were peaks between March / May and September / November. The mean num ber of snails collected was positively correlated with the water plants Nymphaea caerulea and Typha species. Overall, 2.5 % of B. globosus were shedding Schistosoma cercariae. In the highveld, 2.8 % of B. globosus were infected with schistosome cercariae and 1.5 % in the lowveld, with the figures at individual sites ranging from 0-18.8 % in the highveld and from 0-4.5 % in the lowveld. The cercariae recorded here were a mixture of S. mattheei and S. haematobium since they share the same intermediate host. The transmission of Schistosoma cercariae exhibited a marked seasonal pattern, being more intensive during the hot, dry season (September / November).

scholarly journals Multi-year statistical and modeling analysis of submicrometer aerosol number size distributions at a rain forest site in Amazonia

2018 ◽  
Vol 18 (14) ◽  
pp. 10255-10274 ◽  
Author(s):  
Luciana Varanda Rizzo ◽  
Pontus Roldin ◽  
Joel Brito ◽  
John Backman ◽  
Erik Swietlicki ◽  
...  
Keyword(s):  
Particle Size ◽  
Rain Forest ◽  
Amazon Basin ◽  
Particle Number ◽  
Dry Season ◽  
Forest Site ◽  
Size Distributions ◽  
Wet Season ◽  
Accumulation Mode ◽  
Aitken Mode

Abstract. The Amazon Basin is a unique region to study atmospheric aerosols, given their relevance for the regional hydrological cycle and the large uncertainty of their sources. Multi-year datasets are crucial when contrasting periods of natural conditions and periods influenced by anthropogenic emissions. In the wet season, biogenic sources and processes prevail, and the Amazonian atmospheric composition resembles preindustrial conditions. In the dry season, the basin is influenced by widespread biomass burning emissions. This work reports multi-year observations of high time resolution submicrometer (10–600 nm) particle number size distributions at a rain forest site in Amazonia (TT34 tower, 60 km NW from Manaus city), between 2008 and 2010 and 2012 and 2014. The median particle number concentration was 403 cm−3 in the wet season and 1254 cm−3 in the dry season. The Aitken mode (∼ 30–100 nm in diameter) was prominent during the wet season, while the accumulation mode (∼ 100–600 nm in diameter) dominated the particle size spectra during the dry season. Cluster analysis identified groups of aerosol number size distributions influenced by convective downdrafts, nucleation events and fresh biomass burning emissions. New particle formation and subsequent growth was rarely observed during the 749 days of observations, similar to previous observations in the Amazon Basin. A stationary 1-D column model (ADCHEM – Aerosol Dynamics, gas and particle phase CHEMistry and radiative transfer model) was used to assess the importance of the processes behind the observed diurnal particle size distribution trends. Three major particle source types are required in the model to reproduce the observations: (i) a surface source of particles in the evening, possibly related to primary biological emissions; (ii) entrainment of accumulation mode aerosols in the morning; and (iii) convective downdrafts transporting Aitken mode particles into the boundary layer mostly during the afternoon. The latter process has the largest influence on the modeled particle number size distributions. However, convective downdrafts are often associated with rain and, thus, act as both a source of Aitken mode particles and a sink of accumulation mode particles, causing a net reduction in the median total particle number concentrations in the surface layer. Our study shows that the combination of the three mentioned particle sources is essential to sustain particle number concentrations in Amazonia.

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