Habitat use by the hymenosomatid crab Amarinus lacustris (Chilton) in two south-eastern Australian rivers

2005 ◽  
Vol 56 (1) ◽  
pp. 37 ◽  
Author(s):  
Kerrylyn Johnston ◽  
Belinda J. Robson
Keyword(s):  
Habitat Use ◽  
Strong Association ◽  
Population Characteristics ◽  
Timing Of Reproduction ◽  
South Eastern ◽  
Period Distribution ◽  
South West ◽  
Linear Modelling ◽  
Time Of Year ◽  
Log Linear

The hymenosomatid crab Amarinus lacustris is abundant in some south-eastern Australian rivers; however, little is known of its ecology. Patterns of habitat use by crabs in rivers may be affected by seasonal changes in river discharge. This study investigates population characteristics, timing of reproduction and patterns of habitat use by A. lacustris in five riffle and pool habitats from each of the Hopkins and Merri Rivers in south-west Victoria, Australia, sampled over a twelve-month period. Distribution of Amarinus lacustris was similar between the two rivers, but log-linear modelling showed that there was a strong association between crab sex, habitat occupied and time of year because female A. lacustris showed a shift from riffle to pool habitats during March and April, coinciding with the non-gravid period of the year. Male crabs also showed a change in relative occurrence, occurring most often in riffles during winter–spring (July–November) but being equally common in both habitats in summer–autumn (January–May). These patterns are probably the result of the reproductive cycle of A. lacustris, which appears to show both ontogenetic and sex-related changes in habitat use during its life cycle, taking advantage of seasonal fluctuations in flow regime that may assist egg/larval development and dispersal.

THE DISTRIBUTION OF DERMACENTOR TICKS IN CANADA IN RELATION TO BIOCLIMATIC ZONES

1967 ◽  
Vol 45 (4) ◽  
pp. 517-537 ◽  
Author(s):  
P. R. Wilkinson
Keyword(s):  
British Columbia ◽  
Deciduous Forest ◽  
Strong Association ◽  
Eastern Deciduous Forest ◽  
Egg Development ◽  
The North ◽  
Winter Activity ◽  
Bioclimatic Zone ◽  
Soil Temperatures ◽  
Time Of Year

Dermacentor andersoni has been collected north of Jasper, Alberta, close to 54° N. and near 53° N. in British Columbia. Spread to the north and northwest is probably limited by low summer soil temperatures, which would act principally by slowing egg development, thus disrupting the seasonal cycle of the tick. To the southwest, mild winters may fail to release diapause at the correct time of year. Aspect and slope are important factors. Altitude spread of records is from 1000–7000 ft. The most generally applicable description of its distribution is the ecotone between western grassland and moister regions, including clearings and rocky outcrops m the montane and Columbia forests, and shrubby areas of the prairies. In British Columbia, a series of randomly selected transects indicated a strong association between the tick's presence and several species of shrubs growing without tree shade.Each bioclimatic zone tends to have a characteristic group of rodents as main hosts of the immature stages. The prairie and montane regions differ in the indigenous hosts available to the adult tick.East of 105° D. andersoni is replaced by D. variabilis, which is adapted to the more humid summers of the eastern deciduous forest zones, and differs considerably from D. andersoni in its phenology. There are no reliable records of indigenous D. variabilis north of 52° latitude.D. albipictus occurs from the east to the west coast. Because of the winter activity of its larvae, allowing the whole summer for egg development, it is able to penetrate much farther north than the other two species. There are two records close to 60° latitude.

scholarly journals ASSESSMENT OF POPULATION CHARACTERISTICS AND HABITAT USE OF Podocnemis vogli (MÜLLER 1935) DURING A REPRODUCTIVE SEASON AT THE BOJONAWI PRIVATE NATURE RESERVE (VICHADA DEPARTMENT, COLOMBIA)

2020 ◽  
Vol 3 (2) ◽  
pp. 83
Author(s):  
Ana María Sepúlveda-Seguro ◽  
Vivian Patricia Páez ◽  
Marley Tatiana Gómez-Rincón ◽  
Mónica A. Morales-Betancourt ◽  
Carlos A. Lasso
Keyword(s):  
Habitat Use ◽  
Nature Reserve ◽  
Tail Length ◽  
Reproductive Season ◽  
Population Characteristics ◽  
Reproductive Phenology ◽  
Sampling Effort ◽  
Specific Class ◽  
Sexual Characteristics ◽  
Habitat Generalist

We conducted a short study in the Bojonawi Private Nature Reserve (Vichada department, Colombia) in three types of aquatic macrohabitats to characterize habitat use, population structure and reproductive phenology of Podocnemis vogli during one reproductive season. We also reevaluated the degree of sexual dimorphism in this species. To maximize capture rates, we used three methods: funnel traps, trammel nets, and manual capture. Only the funnel traps could be used in a standardized manner in all three macrohabitats. We captured 149 individuals in all age/size classes and obtained 11 recaptures. Since we were able to standardize sampling effort with the funnel traps in all macrohabitats, we compared habitat use and class structure among habitats during this reproductive season. There were no significant differences among the three macrohabitats in terms of relative abundances or size class distributions, but sex ratios differed, with an excess of males in the river and females in the lagoon. As with other congeners, P. vogli is a sexually dimorphic species where females attain larger sizes. In this study we documented that pre-cloacal tail length and nail length on the anterior third toe are the most useful secondary sexual characteristics for sexing subadult and adult individuals. Some females larger than 22 cm straight-line carapace length had calcified eggs in their oviducts. This species is abundant within the reserve and appears to be a habitat generalist, including the use of large rivers. More extensive and intensive monitoring is needed to document specific class survivorship rates, detectabilities and population dynamics.

scholarly journals Fish nursery value of algae habitats in temperate coastal reefs

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6797 ◽  
Author(s):  
Hilmar Hinz ◽  
Olga Reñones ◽  
Adam Gouraguine ◽  
Andrew F. Johnson ◽  
Joan Moranta
Keyword(s):  
Juvenile Fish ◽  
Strong Association ◽  
Late Summer ◽  
Early Spring ◽  
Rocky Reef ◽  
Term Survival ◽  
Fish Nursery ◽  
Prey Biomass ◽  
Reduced Height ◽  
Time Of Year

The nursery function of coastal habitats is one of the most frequently mentioned and recognized ecosystem services in the valuation of coastal ecosystems. Despite its importance our understanding of the precise habitat parameters and mechanisms that make a habitat important as a nursery area is still limited for many species. The study aimed to establish the importance of different algae morphotypes in providing shelter and food for juvenile coastal fish during the main settlement peaks, in early spring and late summer, in littoral rocky reef systems in the Northwestern Mediterranean. The results of our study showed strong seasonal differences in algae cover, composition and height between the two sampling periods. Overall, during spring the algae were well developed, while in late summer, both density and height, of most algae decreased considerably. Equally, prey biomass, in form of suitable sized invertebrate fauna associated to the algae, decreased. Accordingly, the shelter and food for the fish settling in this habitat during late summer were less abundant, indicating a mismatch between the observed presence of juvenile fish and optimal habitat conditions. Differences in prey densities were detected between algae morphotypes, with structurally more complex algae, such as Cystoseira spp. and Halopteris spp. consistently containing more prey, independent of season, compared to simpler structured morphotypes such as Dictoytales. The study furthermore related juvenile fish density to habitats dominated by different algae morphotypes. Out of the three-study species (Diplodus vulgaris, Symphodus ocellatus, Coris julis) only S. ocellatus showed a significant association with an algae habitat. S. ocellatus related positively to habitats dominated by Dictoytales which provided the highest cover during late summer but had the lowest prey densities. A strong association of this species with Cystoseira, as reported by other studies, could not be confirmed. Cystoseira was abundant within the study area but in a state of dieback, showing loss and reduced height of foliage, typical for the time of year within the study area. It is therefore likely that algae-fish associations are context-dependent and that several algae species may fulfil similar functions. We also discovered that prey biomass did not appear to have an important effect on juvenile abundances. Nevertheless, the availability of prey may influence juvenile fish condition, growth performance and ultimately long-term survival. We therefore suggest that future studies on habitat quality should also include, besides abundance, indicators related to the condition and growth of juveniles.

Stemmen in Vlaanderen op 13 december 1987 : Een statistische analyse

Res Publica ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 25-50
Author(s):  
Marc Swyngedouw ◽  
Jaak Billiet
Keyword(s):  
Political Parties ◽  
Democratic Party ◽  
Occupational Status ◽  
The Political ◽  
Voting Behaviour ◽  
National Elections ◽  
Statistische Analyse ◽  
Use Of Data ◽  
Linear Modelling ◽  
Log Linear

Taking into account the limits of such data, this study analyses the shifts in voting behaviour from the national elections in 1985 to those in 1987 in Flanders, using log-linear modelling. The use of data from poll surveys for estimating shifts between subsequent elections poses some methodological problems.The second part presents the results of the analysis. About 13,51 % of -the 1985-voters switched. Although there are significant shifts between all the political parties, the Christian Democratic Party (CVP) loses on all fronts. A log-linear analysis of party-reference by sex, age and occupational status shows the strength and weakness of each party in different societal categories. In conclusion, an interpretation of the shifts is proposed. The following factors can account for the major shifts : the desintegration of the catholic pillar, the emergence of a dual society, the affinity between neo-liberalism and yuppie-culture and the conflict between the language communities.

Habitat use, temporal activity patterns and foraging behaviour of raptors in the south-west of the Northern Territory, Australia

2001 ◽  
Vol 28 (4) ◽  
pp. 365 ◽  
Author(s):  
Tom Aumann
Keyword(s):  
Habitat Use ◽  
Foraging Behaviour ◽  
Activity Patterns ◽  
Northern Territory ◽  
Diel Activity ◽  
The South ◽  
Interspecific Differences ◽  
South West ◽  
Diel Activity Patterns ◽  
Vegetation Structures

On the basis of opportunistic observations, the preferred habitats of diurnal raptors in the south-west of the Northern Territory are quantified in terms of their vegetation structures and composition, and linked with foraging methods and information on local diets. Broad interspecific differences in diel activity patterns are also described. The evidence suggests that raptor species in this part of arid Australia differ with respect to their foraging times, habitats and methods, and that these differences relate to their partitioning of food resources.

Occurrence and habitat use of Bryde's whales (Balaenoptera edeni) in the Cabo Frio region, South-eastern Brazil

2016 ◽  
Vol 98 (5) ◽  
pp. 1081-1086 ◽  
Author(s):  
Israel S. Maciel ◽  
Rodrigo H. Tardin ◽  
Sheila M. Simão
Keyword(s):  
Habitat Use ◽  
Foraging Behaviour ◽  
Field Trips ◽  
South Eastern ◽  
Video Recordings ◽  
Eastern Brazil ◽  
Water Depths ◽  
Cabo Frio

Ninety-six field trips were conducted between summer 2010 and 2012 in order to understand the occurrence and habitat use of Bryde's whale (Balaenoptera edeni) in the Cabo Frio region, South-eastern Brazil. Bryde's whales were present in the study area between November and July, being observed during all seasons, but occur more frequently during the autumn (Nindividuals = 16) and spring (Nindividuals = 13), followed by summer (Nindividuals = 5) and winter (Nindividuals = 2), respectively. Bryde's whales were observed in water depths ranging from 20.1–100 m. Furthermore, during 2240 min of video recordings, the most frequent behaviour observed was foraging (40.2%; 900 min). Travelling comprised 28.1% (630 min) of observations, while in 33.1% (710 min) behaviour could not be determined. Taking into account the pattern of occurrence, the use of deeper bathymetric bins and the frequency observed, the foraging behaviour of Bryde's whales observed in our study seems to be associated to prey dynamics. Our data show that the study area is frequently used for foraging by this species in Brazilian waters.

Characterizing adaptations of serve indicators in top-level male volleyball among seasons

2020 ◽  
pp. 174795412097892
Author(s):  
Konstantinos Sotiropoulos ◽  
Sotirios Drikos ◽  
Sophia D Papadopoulou ◽  
Karolina Barzouka
Keyword(s):  
Correspondence Analysis ◽  
Olympic Games ◽  
Multiple Correspondence Analysis ◽  
Horizontal Axis ◽  
Special Focus ◽  
Linear Modelling ◽  
Chi Squared ◽  
Position Type ◽  
Log Linear

The purpose of this study was to analyse selected serve characteristics in top-level male volleyball, with a special focus on detecting adaptations of the serve skill among seasons. The indicators examined were type, position, direction and quality of serve. The sample consisted of 5482 serves from three final phases of different top-level tournaments (Olympic Games 2012, N = 1942, World League 2017, N = 1883, World Championship 2018, N = 1657). The interrelationships between variables were analyzed using chi-squared tests, log-linear modelling and multiple correspondence analysis. The results showed that the interaction of all serve indicators are statistically important, but the combination of the variables’ categories that were more responsible for association alternated across the seasons under study. A 3-way association term was revealed for season 2012 (type/position/direction) and 2018 (type/position/quality), while for season 2017 multiple 2-way interactions were found (type/position, type/direction, position/quality, direction/quality). The direction of the serve to the horizontal axis of the court was correlated to the quality of serve and consequently with the advantage of the serving team, while a more tactical perspective for serve skill is formed over periods in top level male volleyball.

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