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1

Vertical stratification and its relation to foliage in tropical forest birds in Western Ghats [India]

100%
Jayson E. A., Mathew D. N.
Acta Ornithologica
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2003
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tom 38
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nr 2
The study was carried out from May 1988 to April 1993 in two types of tropical forests: the tropical evergreen and moist deciduous. The vertical distribution of birds and foliage abundance was recorded by visual observation in seven height classes, using the line transect method. The vertical distribution of 94 bird species was recorded in evergreen forest, and of 90 in moist deciduous forest. Bird species richness and the numbers of birds were highest in the stratum from 1 to 5 m in both the evergreen forests (57 species) and the moist deciduous forests (68 species). The species richness indices of birds in the two types of forest did not display such a clear relationship. Foliage abundance was high up to a height of 30 m in the evergreen forests, whereas in moist deciduous forests, foliage was abundant only up to 20 m. A significant positive correlation was obtained between foliage abundance and species richness and also between the numbers of birds in both types of forests. Significant correlation was also obtained between foliage abundance and the species diversity indices in the two types of vegetation.
2
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Processes and factors influencing the through-flow of new deepwater in the Bornholm Basin

86%
Stigebrandt A.
Oceanologia
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2017
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tom 59
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nr 1
This paper is based on the idea that the hydrographical conditions in the Bornholm Basin, and any other basin, can be understood from knowledge of general hydromechanical principles and basin-specific factors. Published results on the variability of the vertical stratification are shown and discussed. Such analyses demonstrate the residence time of water at different depth levels. Different modes of currents forced by winds and by stratification gradients at open vertical boundaries are presented. Vertical mixing is discussed and published results for the Bornholm Basin are shown. An experiment demonstrates that the diffusive properties of the enclosed basin, i.e. below the sill depth of the Słupsk Furrow, can be computed quite well from the horizontal mean vertical diffusivity obtained from historical hydrographical observations. A published two decades long simulation of the vertical stratification shows that the through flow and modification of new deepwater in the Bornholm Basin can be well described based on existing knowledge regarding crucial hydromechanical processes. It also suggests, indirectly, that there should be a weak anticyclonic circulation above the sill depth, which is supported by current measurements.
3

Stride lengths and frequencies of arboreal walking in seven species of didelphid marsupials

86%
Delciellos A. C., Vieira M. V.
Acta Theriologica
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2007
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tom 52
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nr 1
Didelphid marsupials differ in their use of the forest strata, with corresponding differences in morphology and arboreal walking performances. Similar performances may be reached by different combinations of stride length and frequency, but it has been suggested that arboreal walkers increase velocity by longer strides. Our objective was to determine how stride length and frequency contribute to the velocity in the arboreal walking of seven species of didelphid marsupials of the Atlantic Forest of Brazil. Animals were stimulated to cross five 3-m long horizontal supports of different diameters. The cycle of maximum velocity was chosen to measure relative stride length, frequency, and relative velocity. Except forCaluromys philander, the more arboreal species were faster than the terrestrial species, but maximum velocity of arboreal species was reached by two strategies, increasing stride frequency (Gracilinanus microtarsus, Micoureus demerarae, andDidelphis aurita), or reducing frequency and increasing stride length (Marmosops incanus andC. philander). Increasing velocity in arboreal walking by more frequent strides may reduce oscillations of the body, whereas longer strides may reduce branch swaying. Among the terrestrial species,Philander frenatus performed similarly to more arboreal species, suggesting a potential ability to use the canopy, undetected in field observations.
4

On the usefulness of the Cox number in investigations on the intensity of turbulent heat exchange processes in the sea coastal zone

72%
Druet C., Siwecki R.
Oceanologia
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1984
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tom 18
5

Is footprint shape a good predictor of arboreality in sigmondontine rodents from a neotropical savanna?

72%
de Camargo N. F., Ribeiro J. F., Gurgel-Goncalves R., Palma A. R. T., Mendonca A. F., Vieira E. M.
Acta Theriologica
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2012
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tom 57
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nr 3
We investigated the relation between the footprint shape of the fore and hind feet of sigmodontine rodents and their levels of arboreal activity. Footprint shape was obtained by analyzing the impressions left by identified animals captured in the field after being forced to pass through ink-tracking tunnels or by pressing their previously inked feet on a paper sheet. We used geometric morphometric techniques that use superimposition of landmarks (centers of the pads) to obtain footprint shape variables, which were reduced using multivariate analysis (principal component analysis). Arboreal activity was inferred on the basis of the proportions of individuals captured in arboreal traps (1.5–2.5 m height). Regression analysis of body size and the variable that best represented the footprint shapes (first principal component—PC1) did not indicate significant allometric effects on such shapes. We did not detect any significant phylogenetic effects on the arboreal activity of the rodents, either. The results indicated that the PC1 concerning footprint shapes of ten sigmodontine rodents efficiently reflects the degree of use of arboreal strata by these animals. The species studied showed different levels of arboreal activity and their hind footprints (r 2 = 0.94) were better indicators of arboreality than the fore footprints (r 2 = 0.53). These findings suggest a likely trade off for the fore feet functions. Such functions are probably not strictly related to locomotion. Other biomechanical functions (e.g., shock absorption) and/or manipulation (e.g., food manipulation and grooming) may exert relatively greater influence on the shape of fore feet.
6
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Characteristics and inter-annual changes in temperature, salinity and density distribution in the Gulf of Riga

72%
Skudra M., Lips U.
Oceanologia
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2017
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tom 59
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nr 1
Available CTD profiles from the Gulf of Riga (May—August, 1993—2012) were analyzed to study inter-annual and long-term changes in temperature, salinity and density in relation to river runoff and atmospheric forcing (e.g. Baltic Sea Index). To describe temporal changes in vertical stratification, the upper mixed layer (UML) and deep layer (DL) parameters were estimated. On average the UML depth increases from 8.7 m in May to 9.0, 11.5 and 13.7 m in June, July and August, respectively, and the UML temperature increases from 8.08C to 12.5, 18.7 and 18.68C (May, June, July and August) while the UML salinity increases from 4.90 g kg1 to 5.14, 5.28 and 5.38 g kg1, respectively. High correlation (r = 0.82) was found between the inter-annual changes in river runoff (spring) and mean salinity in the UML in August as well as between DL mean salinity (r = 0.88) and density (r = 0.84) in the Irbe Strait and DL mean salinity and density in the Gulf of Riga. Inter-annual changes in the UML depth as well as in DL salinity and density had a significant correlation with the changes in Baltic Sea Index. The strongest stratification (August) can be observed in the years with the highest UML temperature and the highest river run-off in spring. We suggest that the predicted increase in water temperature and changes in river run-off due to the climate change would result in faster development of the seasonal thermocline in spring and stronger vertical stratification in summer.
7
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Baroclinic Rossby radius of deformation in the Southern Baltic Sea

58%
Osinski R., Rak D., Walczowski W., Piechura J.
Oceanologia
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2010
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tom 52
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nr 3
417-429
The first baroclinic Rossby radius of deformation (R1) is a fundamental horizontal scale of mesoscale processes. This scale is important for planning both numerical modelling and study areas. R1 was computed on the basis of an 11-year series of high resolution CTD measurements collected during r/v ‘Oceania’ cruises. The data set covered the three main basins of the Baltic Proper: the Bornholm Basin (BB), the Słupsk Furrow (SF) and the Gdańsk Basin (GB). The smallest mean value of R1 was found in the Gdańsk Basin (5.2 km), the largest one in the Bornholm Deep (7.3 km). The seasonal variability of R1 is lower in the western basin than in the eastern one. The seasonal cycle of R1 may be broken by extreme events, e.g. main Baltic inflows (MBI) of saline water. The inflowing water rebuilds the vertical stratification in the southern Baltic Sea and dramatically changes the R1 values. The difference of R1 between a stagnation period and an inflow situation is shown on the basis of observations made during 2002–2003. The main inflow occurred in winter, after ten years of stagnation, and the very low values of R1 (about 4 km) changed to very high ones (more than 9 km). Analysis of stagnation and saltwater inflow events may throw light on the value of R1 in future climatic scenarios. The potential influence of climate change on Baltic Sea salinity, especially a decrease in MBI activity, may change the baroclinic Rossby radius of deformation and the mesoscale dynamics. Values of R1 are expected to be lower in the future climate than those measured nowadays.
8

Age, season, and arboreal movements of the opossum Didelphis aurita in an Atlantic rain forest of Brasil

58%
Cunha A. A., Vieira M. V.
Acta Theriologica
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2005
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tom 50
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nr 4
551-560
The common opossum of the Atlantic forest,Didelphis aurita Wied-Neuwied, 1826 is predominantly terrestrial, but uses the vertical space of the forest regularly. It is the didelphid that most frequently uses large supports in vertical movements. Here we test the influence of age and seasonality in fruit production on the vertical movements ofD. aurita. Animals were trapped in Serra dos Órgăos, state of Rio de Janeiro, and equipped with a spool-and-line device before release. The paths were tracked, and variables related to support incline, diameter, distances and heights moved above ground were measured and compared between age classes and seasons. There were no significant differences between seasons. Individuals of all ages used the vertical space of the forest but the young opossums did it more intensively along their paths.
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