Seasonal variations in population and community structure of small rodents in a tropical forest of Gabon

2003 ◽  
Vol 81 (6) ◽  
pp. 1034-1046 ◽  
Author(s):  
Violaine Nicolas ◽  
Marc Colyn
Keyword(s):  
Seasonal Variations ◽  
Rainy Season ◽  
Abundant Species ◽  
Reproductive Phenology ◽  
Breeding Activity ◽  
Short Rainy Season ◽  
Murid Rodents ◽  
Undisturbed Forest ◽  
Composition Structure ◽  
The Tropics

The composition, structure, and reproductive phenology of a community of murid rodents were investigated for 1 year at two sites in an undisturbed forest in southwestern Gabon, Africa. We captured 1531 mice belonging to 11 species and eight genera. At both sites, species richness varied seasonally and tended to be maximal during the period of maximal trap success. For the most abundant species (Hylomyscus stella, Hybomys univittatus, Heimyscus fumosus, and Praomys cf. misonnei), a general unimodal trend in trap success was detected, owing to variations in breeding activity and survival, with a minimum around the long rainy season and a maximum either during the short rainy season or at the beginning of the following long dry season. These fluctuations varied in magnitude among species, and seasonal variations in relative abundance were recorded. Our results support the assumption that in the tropics, rainfall and associated patterns of fruit and insect abundance are important factors which may act directly or indirectly to initiate breeding activity so that lactation occurs at a time of greatest food abundance. Finally, intrapopulational differences in age at sexual maturity were found, both between the sexes and among individuals of the same sex.

Seasonal variation in population and community structure of shrews in a tropical forest of Gabon

2005 ◽  
Vol 21 (2) ◽  
pp. 161-169 ◽  
Author(s):  
Violaine Nicolas ◽  
Patrick Barrière ◽  
Marc Colyn
Keyword(s):  
Community Structure ◽  
Seasonal Variation ◽  
Dominant Species ◽  
Abundant Species ◽  
Dry Season ◽  
Reproductive Phenology ◽  
Ecological Constraints ◽  
Species Dominance ◽  
Composition Structure ◽  
Over Time

The composition, structure and reproductive phenology of a shrew community were investigated for 1 y at two neighbouring sites in an undisturbed African forest of south-western Gabon. We captured 717 shrews, belonging to four genera and 10 species. The data were analysed to answer three main questions: (1) to what extent does the shrew abundance vary seasonally? (2) is there a shift in species dominance over time? and (3) does the intensity of breeding activity vary seasonally? The number of species captured varied seasonally and tended to be least during the period of minimal trap success. Trap success for the four most abundant species (Sylvisorex johnstoni, Crocidura batesi, Paracrocidura schoutedeni and Sylvisorex ollula) varied seasonally with a minimum around the long dry season. Sylvisorex johnstoni remained the dominant species throughout the year. Seasonal variation in trap success of shrews might be related, at least partly, to their reproductive characteristics. Litter size, based on embryo counts, ranged from 1–4 among the species. Breeding occurred throughout the year, but its intensity was lower during the long dry season corresponding with the period of higher ecological constraints for shrews.

Effects of Planting Bed and Density on the Yield of Pineapple (Ananas comosus L. var., MD2) Grown in Short Rainy Season in Southern Côte d’Ivoire

2016 ◽  
Vol 11 (1) ◽  
pp. 18-25
Author(s):  
Ouattara Genefol ◽  
Camara Brahima ◽  
Bomisso Edson Lezi ◽  
Cherif Mamadou ◽  
Sorho Fatogoma ◽  
...  
Keyword(s):  
Cote D'ivoire ◽  
Rainy Season ◽  
Côte D’Ivoire ◽  
Ananas Comosus ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Short Rainy Season

scholarly journals Habitat selection by anurofauna community at rocky seashore in coastal Atlantic Forest, Southeastern Brazil

2013 ◽  
Vol 73 (3) ◽  
pp. 533-542 ◽  
Author(s):  
RC. Pontes ◽  
RT. Santori ◽  
FC. Gonçalves e Cunha ◽  
JAL. Pontes
Keyword(s):  
Atlantic Forest ◽  
Rainy Season ◽  
Water Storage ◽  
Southeastern Brazil ◽  
Brazilian Coast ◽  
Water Storage Capacity ◽  
Breeding Activity ◽  
Amphibian Community ◽  
Top View ◽  
Selection Of

Rocky seashores are low granitic hills distributed along the southeastern Brazilian coast with xeric-like vegetation due to the shallow soil. Knowledge on amphibian communities and their reproductive patterns is especially reduced on this kind of environment. Herein, we present a framework of two years monitoring an amphibian community at a rocky seashore environment located at the protected area of Parque Estadual da Serra da Tiririca, municipality of Niterói, state of Rio de Janeiro, Brazil. We conducted diurnal and nocturnal searches for frogs in tank bromeliads, rocky surface and shrubby vegetation. Annual pattern of breeding activity of anurans was also estimated. Individuals of the most abundant tank-bromeliad, Alcantarea glaziouana were collected and measured according to several variables to understanding the selection of bromeliads by frogs. We checked the influence of the environmental conditions on amphibian abundance, association between the bromeliads measures, and the water storage in the tank. We recorded the species: Scinax aff. x-signatus; S. cuspidatus; S. littoreus; Thoropa miliaris and Gastrotheca sp. Bromeliads were the preferential habitat used by anurans. The nocturnal habit was predominant for all species and during diurnal searches, the specimens were found sheltered in bromeliads axils. The number of calling males as well as amphibian abundance was associated with the rainiest and warmest period of the year. The species S. littoreus was observed in breeding activity in the majority of sample period. Adult calling males of T. miliaris were observed especially in the rainy season. Rainfall and temperature combined are positively correlated to the total number of captured amphibians. However, individually, rainfall was not significantly correlated, while temperature was positively correlated with the amphibian abundance. Water storage capacity by bromeliads was correlated to characteristics and size of the plant. In the rainy season, the height of the plant and the diameter on top view were correlated with the occurrence of amphibians, while during the driest period there was no correlation among variables and the bromeliad usage by amphibians. Recorded species were strongly associated to the Atlantic Forest domain. Nevertheless, the occupation of rocky seashores by anurans may be more associated with the specialized reproductive modes presented by species, since there is no permanent water available in ponds or streams.

scholarly journals COMPORTAMENTO FENOLÓGICO DE Emmotum nitens (Benth.) Miers (METTENIUSACEAE) EM FRAGMENTO DE CERRADÃO

Nativa ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 33
Author(s):  
Patrícia Oliveira da Silva
Keyword(s):  
Rainy Season ◽  
Reproductive Phenology ◽  
Fruit Maturation ◽  
Ripe Fruit ◽  
Flower Bud ◽  
Circular Statistic ◽  
Immature Fruit ◽  
Temperature And Precipitation ◽  
Continuous Reproduction ◽  
Reproductive Events

Emmotum nitens é uma espécie bem conhecida em termos de florística e fitossociologia, entretanto, há poucos trabalhos que tratam-se de sua fenologia. Este estudo buscou avaliar a fenologia reprodutiva de uma população de E. nitens no Município de Rio Verde, Goiás. Observou-se mensalmente as fenofases reprodutivas (botão, antese, fruto imaturo e maduro) de 15 indivíduos. Para a coleta dos dados utilizou-se o método de Fournier e presença/ausência, e para analisar os mesmos utilizou-se a estatística circular e correlação com as variáveis meteorológicas (temperatura e precipitação). E. nitens produziu botões e flores de modo irregular ao longo do estudo, no entanto se correlacionaram positivamente com a temperatura. Durante todo estudo registrou-se frutos imaturos, embora as maiores concentrações ocorreram na transição do período seco-chuvoso e durante as chuvas, correlacionando-se positivamente com a precipitação. A maturação dos frutos iniciou-se no final da estação das chuvas, com maiores intensidades no período seco. Para E. nitens é mais vantajoso apresentar reprodução continua já que a mesma não é fortemente limitada pelas variáveis climáticas da área de estudo, do que seguir um padrão sazonal.Palavra-chave: fenologia, espécie de cerrado, eventos reprodutivos, correlação com metereologia. PHENOLOGICAL BEHAVIOR OF EMMOTUM NITENS (BENTH.) MIERS (METTENIUSACEAE) ON CERRADÃO FRAGMENT ABSTRACT:Emmotum nitens is a well-known species in terms of floristic and phytosociology, however, there are few studies that deal with its phenology. The objective of this study was to evaluate the reproductive phenology of a population of E. nitens in the municipality of Rio Verde, Goiás. The reproductive phenomena (flower bud, anthesis, immature fruit and ripe fruit) were observed monthly in 15 individuals. Fournier method and presence/absence were used to collect the data, and to analyze them, the circular statistic and correlation with the meteorological variables (temperature and precipitation) were used. E. nitens produced flower bud and flowers irregularly throughout the study, however they correlated positively with temperature. During the whole study immature fruits were recorded, although the highest concentrations occurred in the transition from the dry-rainy season and during the rains, correlating positively with the precipitation. Fruit maturation began at the end of the rainy season, with higher intensities in the dry season. For E. nitens it is more advantageous to present continuous reproduction since it is not strongly limited by the climatic variables of the study area, rather than following a seasonal pattern.Keywords: phenology, species of cerrado, reproductive events, correlation with meteorology. DOI:

scholarly journals Producción de estructuras reproductivas y fenología reproductuva de cinco especies de compuestas en una comunidad xerófita

2017 ◽  
pp. 67
Author(s):  
Dulce María Figueroa-Castro ◽  
Zenón Cano-Santana ◽  
Edgar Camacho-Castillo
Keyword(s):  
Rainy Season ◽  
Reproductive Period ◽  
Dry Season ◽  
Reproductive Phenology ◽  
Central Mexico ◽  
Light Conditions ◽  
Mature Fruit ◽  
Reproductive Structures ◽  
Open Site ◽  
Fruit Stage

We studied the production of reproductive structures and the reproductive phenology of five Compositae species in a xeric community in Central Mexico: Eupatorium petiolare, Tagetes lunulata, Senecio praecox, Dahlia coccinea and Verbesina virgata. The last three species were studied in two sites with contrasting light conditions. The number of reproductive structures produced by D. coccinea was higher in the open site than in the shaded one. In contrast, S.praecox had a higher production in the shaded site, but V. virgata showed no differences. The reproductive phenology of V. virgata and D. coccinea was different between sites, but it was not happen in S. praecox. The species that flowered during the dry season had a shorter reproductive period (E. petiolare: 2.8 mo; S. praecox: 2.0 mo) than those that flowered during the rainy season or during the late rainy season (D. coccinea: 11.0 mo; T. lunulala: 8.5 mo; V. virgata: 8.5 mo) , which was caused by the high duration of the mature fruit stage in these species.

Reproductive phenology of sympatric taxa of Chamaecrista (Leguminosae) in Serra do Cipó, Brazil

1999 ◽  
Vol 15 (4) ◽  
pp. 463-479 ◽  
Author(s):  
João A. Madeira ◽  
G. Wilson Fernandes
Keyword(s):  
Seed Predation ◽  
Rainy Season ◽  
Plant Architecture ◽  
Abiotic Factors ◽  
Reproductive Phenology ◽  
Biotic Factors ◽  
Selective Force ◽  
Monthly Average ◽  
Serra Do Cipó ◽  
Mature Seeds

Reproductive phenology of 13 sympatric taxa of Chamaecrista in three sections was surveyed at Serra do Cipó, south-east Brazil. Mean abundance of flowers and fruits per plant and mean number of aborted, predated, and surviving seeds per fruit were estimated. Monthly average number of developed seeds per fruit multiplied by the monthly mean number of fruits per plant gave the monthly average number of seeds produced by a plant of each taxon. Five types of phenological behaviour were differentiated by cluster analyses according to the season during which each species produced most of its mature seeds. This behaviour was related to the taxonomic section to which the taxa belong, to plant architecture, to geographical range, to seed predation and to local climatic seasonality. Herbs were more affected by variation in rainfall than shrubs and trees. Two species did not show any clear seasonal behaviour. Widespread taxa produced most of their mature seeds in the rainy season or immediately after it, and all but one of the narrowly distributed species produced most of their mature seeds in the dry season or in the transition from dry to rainy season. Seed predation is probably not an important selective force affecting reproductive phenology of larger taxa, while the smaller taxa seemed too constrained by abiotic factors for biotic factors to influence their phenology significantly.

scholarly journals Influence of habitat connectivity and seasonality on the ichthyofauna structure of a riverine knickzone

2018 ◽  
Vol 108 (0) ◽  
Author(s):  
Eduardo M. Brambilla ◽  
Virginia S. Uieda ◽  
Marcos G. Nogueira
Keyword(s):  
Rainy Season ◽  
Power Plants ◽  
High Water ◽  
Abundant Species ◽  
Fish Diversity ◽  
Hydroelectric Power ◽  
Two Factors ◽  
Dry Conditions ◽  
Flood Pulses ◽  
Imminent Threat

ABSTRACT Knickzones are originated from basaltic outcroppings, present runs, riffles and pools and are highly influenced by flood pulses, which maintain their natural dynamic. However, the construction of hydroelectric power plants alters or eliminate the dynamism of this area and can affect the resident fauna that may be dependent on it. The aim of this study was to evaluate the organization of a knickzone’s ichthyofauna considering the influence of seasonality and connectivity of habitats. The study was performed in a knickzone located in the Sapucaí-Mirim River, Southeast Brazil. We sampled four rocky pools connected to the river and three isolated pools, during rainy and dry conditions. The analysis of the two factors (connectivity and seasonality) and of their interaction showed a significant influence only for seasonality on ichthyofauna structure, with higher values of abundance in the rainy season. The species that most contributed to the high dissimilarity between seasons were Knodus moenkhausii (50% of contribution) and Astyanax bockmanni (21%). The former is the most abundant species in the rainy season and the later in the dry season. The alteration between low and high water level occurs frequently in knickzones, as it is a rocky shallow platform in the middle of a river, with floods occurring seasonally or in stochastic short-term periods. This hydrological seasonal dynamic, high limnological variability and complex interactions of different habitats (pools, runs and rapids) explain the particular ichthyofauna structure in such small area. Our results also indicate the potential importance of basaltic knickzones for regional fish diversity conservation, especially due to the imminent threat by intensive hydropower reservoir construction.

Nocturnal Mosquitoes of Pará State in the Brazilian Amazon: Species Composition, Habitat Segregation, and Seasonal Variation

2020 ◽  
Vol 57 (6) ◽  
pp. 1913-1919
Author(s):  
Walter Santos de Araújo ◽  
Thallyta Maria Vieira ◽  
Guilherme Antunes de Souza ◽  
Isaque Clementino Bezerra ◽  
Paulo Henrique Costa Corgosinho ◽  
...  
Keyword(s):  
Culex Quinquefasciatus ◽  
Disease Transmission ◽  
Rainy Season ◽  
Mosquito Species ◽  
Species Abundance ◽  
Abundant Species ◽  
Dry Season ◽  
Habitat Segregation ◽  
Vector Species ◽  
High Degree

Abstract Mosquitoes (Diptera: Culicidae) are one of the most important disease vector species in the world. Many species have a high degree of anthropophilia and are often found in human habitations. In the present study, we have inventoried the nocturnal mosquito assemblage in intra-, peri-, and extradomicile environments in four municipalities in Pará, Brazil. At each municipality, a residence was selected and the mosquitoes were sampled using the protected human attraction capture and Shannon trap methods in April (rainy season) and August 2018 (dry season). We have collected a total of 696 mosquito specimens belonging to 8 genera and 17 species. The most abundant species were Mansonia (Mansonoides) titillans (Walker) (366/696, 52.6%), Anopheles (Nyssorhynchus) albitarsis Lynch-Arribálzaga (97/696, 13.9%), and Culex (Culex) quinquefasciatus Say (93/696, 13.4%). Mosquito richness, abundance, and composition did not differ between intra-, peri-, and extradomicile environments suggesting limited habitat segregation among the different species. However, mosquito species richness and mosquito species abundance were significantly higher during the rainy season than during the dry season, suggesting increased mosquito activity during the rainy season. We detected several important vector species of human diseases including Aedes (Stegomyia) aegypti (Linnaeus), Anopheles (Nyssorhynchus) darlingi Root, Haemagogus (Conopostegus) leucocelaenus (Dyar and Shannon), Coquillettidia (Coquillettidia) venezuelensis (Theobald), and Culex (Culex) quinquefasciatus which are the main transmitters of dengue, malaria, yellow fever, mayaro, and oropouche fever, respectively. As inventories of disease-carrying mosquitoes in the region are very scarce, mainly in residential environments, our results suggest high potential for mosquito-borne disease transmission in Pará State.

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