Physical body parameters of red-crowned cranes Grus japonensis by sex and life stage in eastern Hokkaido, Japan.

Red-crowned (or Japanese) cranes Grus japonensis are native to eastern Hokkaido, Japan--the island population, and mainland Asia--the continental population that migrates from breeding grounds along the Amur River Basin to winter in east China and the Korean Peninsula. The island population was reduced to about 50-60 birds in early part of the 20th century. Since 1950s, the population has increased to more than 1,300 as a consequence of human-provided food in winter, resulted in change of their habitats and food resource. From the carcasses of 284 wild cranes from the island population, collected in Hokkaido since 1976 until 2010, we measured six physical parameters (body weight and lengths of body, wing, tarsus, tail and exposed culmen) and divided into groups by sex and three developmental stages (juvenile, yearling and adult). All parameters of males were larger than those of females at the same stage. Total body length of females tends to grow up earlier than males, in contrast to body weight. Obvious time trends were not observed in these all parameters during 34 years for these six categories measured, except total length of male juveniles, which showed a significant increasing trend. These results provide the first extensive data on body size and mass in the wild red-crowned cranes.

Tracing the sources of gaseous components (222Rn, CO2 and its carbon isotopes) in soil air under a cool-deciduous stand in Sapporo, Japan.

Radon ((222)Rn) and carbon dioxide were monitored simultaneously in soil air under a cool-temperate deciduous stand on the campus of Hokkaido University, Sapporo, Japan. Both (222)Rn and CO(2) concentrations in soil air varied with atmospheric (soil) temperature in three seasons, except for winter when the temperature in soil air remained constant at 2-3 degrees C at depth of 80 cm. In winter, the gaseous components were influenced by low-pressure region passing through the observation site when the ground surface was covered with snow of ~1 m thickness. Carbon isotopic analyses of CO(2) suggested that CO(2) in soil air may result from mixing of atmospheric air and soil components of different origins, i.e. CO(2) from contemporary soil organic matter and old carbon from deeper source, to varying degrees, depending on seasonal meteorological and thus biological conditions.

Meteorological parameters contributing to variability in 222Rn activity concentrations in soil gas at a site in Sapporo, Japan.

Continuous (222)Rn monitoring in soil gas since November 22, 2004 has revealed variability in activity concentration with time in the semi-natural woods on the campus of Hokkaido University in Sapporo, Japan. Among various factors affecting soil radon levels and variability, temperature was found to be dominant during three seasons when activity concentrations of (222)Rn showed a diurnal high and nocturnal low with a boundary around 10 o'clock in the morning. This pattern was disturbed by low pressure fronts with occasional rain. The activity gradually decreased as soil temperatures decreased from late November to mid-December. After the ground surface was completely covered with snow, soil radon levels became low with a small fluctuation. There were several peaks of (222)Rn on the time-series chart in winter. Those peaks appearing in early winter and early spring may be interpreted by considering meteorological parameters. In a few cases, the radon activity suddenly increased with increasing pressure in the soil at a depth of 10 cm, which may be associated with subsurface events such as seismic activity in the area.