The Influence of Seasonal Differences on the Growth of Navajo Lambs

The seasonal variations of raindrop size distribution (DSD) and rainfall are investigated using three-year (2016–2018) observations from a two-dimensional video disdrometer (2DVD) located at a suburban station (40.13°N, 116.62°E, ~30 m AMSL) in Beijing, China. The annual distribution of rainfall presents a unimodal distribution with a peak in summer with total rainfall of 966.6 mm, followed by fall. Rain rate (R), mass-weighted mean diameter (Dm), and raindrop concentration (Nt) are stratified into six regimes to study their seasonal variation and relative rainfall contribution to the total seasonal rainfall. Heavy drizzle/light rain (R2: 0.2~2.5 mm h−1) has the maximum occurrence frequency throughout the year, while the total rainfall in summer is primarily from heavy rain (R4: 10~50 mm h−1). The rainfall for all seasons is contributed primarily from small raindrops (Dm2: 1.0~2.0 mm). The distribution of occurrence frequency of Nt and the relative rainfall contribution exhibit similar behavior during four seasons with Nt of 10~1000 m−3 registering the maximum occurrence and rainfall contributions. Rainfall in Beijing is dominated by stratiform rain (SR) throughout the year. There is no convective rainfall (CR) in winter, i.e., it occurs most often during summer. DSD of SR has minor seasonal differences, but varies significantly in CR. The mean values of log10Nw (Nw: mm−1m−3, the generalized intercept parameter) and Dm of CR indicate that the CR during spring and fall in Beijing is neither continental nor maritime, at the same time, the CR in summer is close to the maritime-like cluster. The radar reflectivity (Z) and rain rate (?) relationship (Z = ?R?) showed seasonal differences, but were close to the standard NEXRAD Z-R relationship in summer. The shape of raindrops observed from 2DVD was more spherical than the shape obtained from previous experiments, and the effect of different axis ratio relations on polarimetric radar measurements was investigated through T-matrix-based scattering simulations.

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Benthic invertebrate assemblages and leaf‐litter breakdown along the eucrenal–hypocrenal ecotone of a rheocrene spring in Central Italy: Are there spatial and seasonal differences?

Ecohydrology ◽

10.1002/eco.2289 ◽

2021 ◽

Author(s):

Antonio Di Sabatino ◽

Luca Coscieme ◽

Francesco Paolo Miccoli ◽

Giovanni Cristiano

Keyword(s):

Leaf Litter ◽

Central Italy ◽

Benthic Invertebrate ◽

Litter Breakdown ◽

Seasonal Differences ◽

Leaf Litter Breakdown ◽

Invertebrate Assemblages

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Potential displacement of the native Tenuisvalvae notata by the invasive Cryptolaemus montrouzieri in South America suggested by differences in climate suitability

Bulletin of Entomological Research ◽

10.1017/s000748532100033x ◽

2021 ◽

pp. 1-11

Author(s):

Larissa F. Ferreira ◽

Christian S. A. Silva-Torres ◽

Jorge B. Torres ◽

Robert C. Venette

Keyword(s):

Biological Control ◽

South America ◽

Prey Availability ◽

Ecological Factors ◽

Growth Conditions ◽

Cryptolaemus Montrouzieri ◽

Seasonal Differences ◽

Ladybird Beetle ◽

Ecoclimatic Index ◽

Climate Suitability

Abstract Tenuisvalvae notata (Mulsant) (Coccinellidae) is a predatory ladybird beetle native to South America. It specializes in mealybugs prey (Pseudococcidae), but relatively little is known about its ecology. In contrast, the ladybird beetle Cryptolaemus montrouzieri Mulsant (Coccinellidae) is indigenous to Australia and has been introduced to many countries worldwide including Brazil for biological control of mealybugs. The potential impacts of these introductions to native coccinellids have rarely been considered. The software CLIMEX estimated the climate suitability for both species as reflected in the Ecoclimatic Index (EI). Much of South America, Africa, and Australia can be considered climatically suitable for both species, but in most cases, the climate is considerably more favorable for C. montrouzieri than T. notata, especially in South America. The CLIMEX model also suggests seasonal differences in growth conditions (e.g. rainfall and temperature) that could affect the phenology of both species. These models suggest that few locations in South America would be expected to provide T. notata climatic refugia from C. montrouzieri. Although other ecological factors will also be important, such as prey availability, this analysis suggests a strong potential for displacement of a native coccinellid throughout most of its range as a consequence of the invasion by an alien competitor.

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Seasonal differences in migration strategies of Red Kites (Milvus milvus) wintering in Spain

Journal of Ornithology ◽

10.1007/s10336-021-01918-5 ◽

2021 ◽

Author(s):

Jorge García-Macía ◽

Javier Vidal-Mateo ◽

Javier De La Puente ◽

Ana Bermejo ◽

Rainer Raab ◽

...

Keyword(s):

Spring Migration ◽

Great Variability ◽

Autumn Migration ◽

Seasonal Differences ◽

North Eastern ◽

Wintering Areas ◽

Satellite Transmitters ◽

Migration Strategies ◽

Migratory Movements ◽

Milvus Milvus

AbstractRed Kite shows a great variability in its migration strategies: most individuals in north-eastern Europe are migrants, but there is also a growing number of sedentary individuals. Here, we tagged 49 Red Kites wintering in Spain with GPS/satellite transmitters between 2013 and 2020 to study the autumn and spring migration between the breeding or summering areas in Central Europe and the wintering quarters in Spain. In first place, differences between immatures and adults were found for spring migration. Adults began the spring migration towards the northeast in February–March while the immature individuals began to migrate significantly later and showing a wider date range (February-June). Adults also takes significantly less days to arrive at their destinations (12 ± 5 days) and cover more distance per day (134.2 ± 37.1 km/day) than immatures (19 ± 11 days and 98.9 ± 21.2 km/day). In second place, we also found differences between spring and autumn migration (excluding immatures). Spring migrations were clearly faster and with less stopovers days than autumn migrations. Autumn migration began between mid-October and late November and two different behaviours were observed: most birds made a quick migration direct to the wintering areas with only some days of stopovers, but others prolonged the migration with long stops along the route. These results highlight a great variation in the migratory movements of Red Kite, not only according to age but also between individuals and seasons.

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Mosquito Species breeding in “Test” Water Containers in West Africa

Bulletin of Entomological Research ◽

10.1017/s0007485300035446 ◽

1933 ◽

Vol 24 (4) ◽

pp. 483-491 ◽

Cited By ~ 8

Author(s):

Cornelius B. Philip

Keyword(s):

Mosquito Species ◽

Weather Conditions ◽

Dense Population ◽

Seasonal Differences ◽

The Third ◽

Several Variables ◽

Test Water ◽

Aedes Africanus ◽

Optimum Type ◽

Mango Leaves

Observations additional to those made by Dunn (1927) of Culicine mosquitos breeding in “ test ” water containers about a Compound in Southern Nigeria, near Lagos, are here reported for a period of the year (June to December) not covered in Dunn's study. Only the optimum type of container mentioned in Dunn's report (bamboo joints containing water and mango leaves) was employed, and these were placed in the same ten representative environmental situations. The numerical rank of infesting species differed significantly in the two studies only in the case of Culex decens, which dropped from third to last place, and of Aëdes africanus, which rose from tenth to sixth place. The total numbers of infestations in the former study were greater, but this is explainable on the basis of one or several variables, i.e., seasonal differences, elapse of time between studies, or less probably the fact that there were four containers instead of one at each station. The number of infestations at any one station has little relation to the number of resultant adults; there is a wide variation in these numbers.An analysis of the occurrence of A. aegypti in containers and a discussion of certain bionomical information together with relative weather conditions are included. Brief data are also presented of the incidence of species at three additional stations, one in a centre of dense population (Lagos), one in a suburb (Ebute Metta), and the third isolated in dense “ bush.”

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The use of faecal nitrogen as an index for estimating the consumption of herbage by grazing animals

The Journal of Agricultural Science ◽

10.1017/s0021859600013666 ◽

1963 ◽

Vol 61 (1) ◽

pp. 33-43 ◽

Cited By ~ 11

Author(s):

G. W. Arnold ◽

M. L. Dudzinski

Keyword(s):

Organic Matter ◽

Nitrogen Concentration ◽

Linear Equations ◽

Slope Position ◽

Seasonal Differences ◽

Faecal Nitrogen ◽

Independent Variable ◽

Regression Relations ◽

The Relationship ◽

Better Than

Data from thirty-five digestibility trials with sheep in metabolism cages were used to investigate statistically the relationships between organic matter intake (I), faecal organic matter output (F), and the nitrogen concentration in faecal organic matter (N).The data fell easily into groups due to botanical or seasonal differences in the feed. These groups of data were homogeneous and provided highly significant linear equations of the forms I = bF + cFN and I = a + cFN. When compared these groups of data sometimes showed differences in slope, position or both. A quadratic expressionI = bF + cFN + dFN2was found to accommodate a majority of the data but to be less precise than I = a + cFN.A further expression incorporating N as an independent variable was also examined,I = a + cFN2 + eN.This expression, although far from being universally adequate, proved to be generally better than existing formulae. When applied to the data of Greenhalgh et. al. (1960), it substantially reduced heterogeneity between data for spring and data for summer pastures.Causes of variation in the relationship between organic-matter intake and nitrogen in faeces, and some of the hazards of extrapolation from empirical regression relations, are discussed.

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