bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pollination systems in a warm temperate evergreen broad‐leaved forest on Yaku Island
Authors: Yumoto Takakazu 
Published: March 2006

AbstractAnimal pollination in a warm temperate evergreen broad‐leaved forest was observed on Yaku‐shima Island, south of Kyushu, Japan. Three groups of plants were categorized: canopy‐flowering tree species, understory‐flowering tree species, and climber and epiphyte species. Each of these formed different pollination systems. The canopy‐flowering tree species had shallow, dish‐shaped flowers and utilized various types of opportunistic pollinators. Most of the climber and epiphyte species had deep, tube‐shaped flowers and specialized pollinators, although some climber species which bloomed in the canopy especially in winter, had opportunistic pollinators. The understory‐flowering tree species had large dish‐ or funnel‐shaped flowers and endothermic pollinators able to tolerate the dark and cold conditions under the canopy. The individual trees of canopy‐flowering tree species produced large numbers of flowers simultaneously (mass‐flowering) and had a well synchronized flowering period. Each canopy‐flowering tree species segregated its flowering time from those of the anothers. Climber and epiphyte species and most of the understory‐flowering tree species produced small numbers of flowers sequentially (extended flowering) and showed a long flowering period.
Seed dispersal of the Korean pine,Pinus koraiensis, by the red squirrel,Sciurus vulgaris
Authors: Miyaki Masami 
Published: March 2006

AbstractSeed hoarding behavior of the red squirrel,Sciurus vulgaris, was studied in relation to the amount of dispersed seeds of the Korean pine,Pinus koraiensis, and the distribution of its seedlings. After removing a cone from a tree, squirrels sat on the ground and ripped off its cone scales before transporting it. A mean of 3.2 seeds were scatter‐hoarded per hole. Of 7.7×104mature seeds produced in a 0.21 ha planted Korean pine forest, 22% were estimated to be directly eaten by four squirrels, 9% were hoarded by them in the pine forest and 65% were cached outside the forest. Squirrels rediscovered hoarded seeds frequently, until the ground was covered with snow, during the period from snow fall until seed germination the next spring, few hoarded seeds were utilized. Korean pine seedlings were found up to 600 m from their mother trees. Scatter‐hoarding by squirrels extensively contributes to seed dispersal to places suitable for the regeneration of the Korean pine. The large size of the cone, the absciss‐layer at the cone penduncle, the infrequent dehiscence of cone scales, the large and wingless seeds, and the thick seed‐coats have probably all been specialized to facilitate utilization by GenusSciurus.
Reproductive ecology of three ocypodid crabs I. The influence of activity differences on reproductive traits
Authors: Henmi Yasuhisa , Kaneto Mitsuaki 
Published: March 2006

AbstractReproductive traits of three ocypodid crabs, Scopimera globosa, Ilyoplax pusillus and Macrophthalmus japonicus, were compared. S. globosa and I. pusillus, inhabiting the upper‐middle intertidal zone, produced 1–2 large broods per year, whereas M. japonicus, inhabiting the lower intertidal zone, produced 4–5 small broods per year. In S. globosa and I. pusillus, ovigerous females remained in their plugged burrows without feeding until their eggs hatched. On the other hand, female M. japonicus fed actively on surface mud while incubating. We concluded that few large broods may be advantageous in crab species that incubate in burrows, whereas continuous small broods may be advantageous in species that feed actively while incubating.
Production ecology of phyto‐ and zooplankton in a eutrophic pond dominated byChaoborus flavicans(Diptera: Chaobolidae)
Authors: Iwakuma Toshio , Shibata Kin'ya , Hanazato Takayuki 
Published: March 2006

AbstractPrimary production of phytoplankton and secondary production of a daphnid and a chaoborid were studied in a small eutrophic pond. The gross primary production of phytoplankton was 290 gC m−2per 9 months during April–December. Regression analysis showed that the gross primary production was related to the incident solar radiation and the chlorophyllaconcentration and not to either total phosphorus or total inorganic nitrogen concentration. The mean chlorophyllaconcentration (14.2 mg m−3), however, was about half the expected value upon phosphorus loading of this pond. The mean zooplankton biomass was 1.60 g dry weight m−2, of whichDaphnia roseaand cyclopoid copepods amounted to 0.69 g dry weight m−2and 0.61 g dry weight m−2, respectively. The production ofD. roseawas high during May–July and October and the level for the whole 9 months was 22.6 g dry weight m−2.Chaoborus flavicansproduced 10 complete and one incomplete cohorts per year. Two consecutive cohorts overlapped during the growing season. The maximum density, the mean biomass, and the production were 19,100 m−2, 0.81 g dry weight m−2, and 11.7 g dry weight m−2yr−1, respectively. As no fish was present in this pond, the emerging biomass amounted to 69% of larval production. The production ofC. flavicanslarvae was high in comparison with zooplankton production during August–September, when the larvae possibly fed not only on zooplankton but also algae.
Climate and vegetation in China II. Distribution of main vegetation types and thermal climate
Authors: Fang Jing‐yun , Yoda Kyoji 
Published: March 2006

AbstractThe authors examined relationships between Kira's warmth index (WI) and four other important thermal indices: the sums of daily mean temperatures above 5°C and 10°C, Thornthwaite's potential evapotranspiration (PE) and Holdridge's annual biotemperature. The thermal records of 671 meteorological stations evenly located all over China were used to make these comparisons. Close correlations were found within the four relationships, and accordingly WI was used to analyse the thermal distributions of the main vegetation types. Vegetation types around the 671 stations were read from a vegetation map with a scale of 1/4000000. Vegetation types at 269 stations corresponded to the natural or seminatural vegetation, and 29 vegetation types were distinguished by arranging the 269 data into the same or similar types. The geographical distribution of these 29 types and the corresponding main climatic features were described. The relations between WI and distribution of these vegetation types were discussed in detail. As a result, WI values (°C month) corresponding to the vegetation zones could be summarized as follows: (1) arctic or alpine vegetation zone: 0–15; (2) boreal or subalpine vegetation zone: 15‐(50–55); (3) cool‐temperate vegetation zone: (50–55)–(80–90); (4) warm‐temperate vegetation zone: (80–90)–(170–180). These values almost coincided with Kira's values.
A preliminary study of changes in forest stratification along environmental gradients in Southeast Asia
Authors: Yamakura Takuo , Sahunalu Pongsak , Karyono  
Published: March 2006

AbstractChanges in forest stratification along environmental gradients in Southeast Asian forests were studied, by applying Quantification Method I to the records of tree height inventories and environmental conditions in 29 study forest stands. To stratify individual trees into subpopulations in a stand, an empirical and graphical method was used. After stratifying all the component individuals of the stand into subpopulations, the number of subpopulations per stand and mean tree height per subpopulation were calculated and adopted as indices of forest stratification. Of the two indices, the latter index changed linearly with respect to the maximum tree height in the stand. Hence, the number of subpopulations and the maximum tree height as a substitute for mean tree height per subpopulation were biotic dependent variables in the application of Quantification Method I, while abiotic independent variables were the following six categorized environmental factors: the number of wet months with over 100 mm month−1 rainfall in a year, occurrence of fog, mean annual temperature, magnesium accumulation in mineral soil, soil water drainage, and forest fire. It was concluded that these biotic and abiotic variables were the components of multivariate regression models, which successfully explained the development of forest stratification in terms of habitat conditions.
Changes in the chemical composition of carbohydrates and proteins in surface water during a bloom of Microcystis in Lake Suwa
Authors: Amemiya Yumiko , Kato Kenji , Okino Tokio , Nakayama Oki 
Published: March 2006

AbstractCarbohydrates and proteins in surface water during a bloom of Mictrocystis, which is the dominant summer phytoplankton in Lake Suwa, were analyzed in order to evaluate the function of Microcystis in organic matter metabolism. Glucose was the predominant sugar constituent of the cellular carbohydrate fraction and decreased in quantity from inside towards the outside of the cell through the slime layer. Other constituent sugars, on the other hand, were present in larger proportions in the lake water. Although the sugar composition of the cells did not change in July and August, during the first period of the Microcystis bloom, it changed appreciably in September when the water temperature decreased below 20°C accompanied by the decrease in solar radiation and a marked change in nutrient concentration.It appears that the sugar composition of the cells may change in response to some environmental stresses. In addition, a temporal change in the sugar composition was found, particularly in the fraction containing the slime extracted by shaking. Among the constituent amino acids of the cells, the percentage of arginine, aspartic acid and leucine decreased from inside toward the outside of the cell, while glutamic acid, threonine, serine and glycine showed an opposite trend. In contrast to the carbohydrates, the percentage composition of each amino acid varied little throughout the period of the bloom.
Germination traits and seed‐bank dynamics of a biennial plant, Oenothera glazioviana Micheli
Authors: Kachi Naoki 
Published: March 2006

AbstractA study was conducted on the germination traits and seed‐bank dynamics of Oenothera glazioviana (=O. erythrosepala), which sets seed in August in sand‐dune systems in Japan. More than 90% of freshly matured seeds germinated over a wide range of temperature in light, but less than 10% did so in continuous darkness. Stratification (chilling under moist conditions) was ineffective in diminishing the light‐requirement for germination. When fresh seeds were imbibed for 24 h including a 12‐h light period, followed by 7‐day air‐drying, 94% of them became germinable in the dark at 25°C, but remained dormant at less than 15°C. of seeds collected in March from capsules of dead plants, 58% germinated in the dark at 25°C. After four cycles of alternatc 1‐day wetting followed by 2‐day drying or 1.5‐day wetting followed by 1.5‐day drying under a 12‐h photoperiod, the fraction of viable seeds declined from 76% to 40% and 22%, respectively, due to germination during the wet periods.Seed‐bag experiments were conducted in the field, using seeds given and not given a light‐stimulus. Forty percent of the light‐stimulated seeds germinated in the soil, whereas the seeds without a light‐stimulus remained dormant throughout the experiment. When seeds were placed on the soil surface or at a depth of 0.5‐1 cm, the proportion of germinable seeds declined during late spring and autumn, but not during winter and early spring. The seed‐bank size of a natural population just prior to current seed dispersal was 2–3% of the seed production in the previous year, suggesting a high turnover rate of the seed‐bank.
Field measurement of net photosynthesis of mosses at Langhovde, East Antarctica
Authors: Ino Yoshio 
Published: March 2006

AbstractNet photosynthesis and dark respiration (CO2 flux) of Antarctic mosses were measured at Langhovde, East Antarctica, from 9 to 17 January 1988. Moss blocks were taken from communities in the Yukidori Valley (69°14′30″S, 39°46′00″E) at Langhovde. Each block was composed of Ceratodon purpureus and Bryum pseudotriquetrum, or B. pseudotriquetrum. The upper part of the block was used to measure net photosynthesis and dark respiration. The net photosynthesis of each sample was measured in the field for one or three days with two infrared CO2 gas analyzers and an assimilation chamber. The relationships of net photosynthetic rate and dark respiration rate, to the water content of the sample, the intensity of solar radiation and the moss temperature were estimated from the field data. The maximum rate of net photosynthesis was about 4 μmol CO2 m−2s−1 at saturating radiation intensity and at optimum temperature, about 10°C. Environmental features of moss habitats in the Yukidori Valley are discussed in relation to these results.
Holocene sedimentary history of some coastal plains in Hokkaido, Japan V. Sedimentary history of Kushu Lake and Akkeshi
Authors: Kumano Shigeru , Ihira Masashi , Kuromi Mitsuhiro , Maeda Yasuo , Matsumoto Eiji , Nakamura Toshio , Matsushima Yoshiaki , Sato Hiroshi , Matsuda Isao 
Published: March 2006

AbstractDiatom assemblages of sediments obtained from Kushu Lake and Akkeshi were analyzed in order to clarify the local Holocene sedimentary history. The results revealed the following: 1) Sometime before about 9000 yr B.P., Kushu Lake was originally a freshwater environment. 2) The first marine diatom zone (MD1Zone) was deposited on the bottom of the paleo‐Kushu Bay between 8500 and 6000 yr B.P. 3) This site changed to become the bottom of the paleo‐Kushu Lagoon around 6000 yr B.P. owing to the formation of a bay‐mouth bar across the paleo‐Kushu Bay and the first Holocene regression resulted in a freshwater lake at about 4500 yr B.P. 4) At this time, the Akkeshi site changed from a sublittoral shore in a drowned valley to a peat moor. 5) The second Holocene transgression at about 3000 yr B.P. was detected at the Akkeshi site. 6) At Kushu Lake site the occurrence ofMastogloia ellipticabetween 7000 and 5000 yr B.P. suggested the influx of the Tsushima warm current into the Japan Sea.
Climate and vegetation in China IV. Distribution of tree species along the thermal gradient
Authors: Fang Jing‐yun , Yoda Kyoji 
Published: March 2006

AbstractThe aim of this study was to examine correlations between vegetational zones and thermal climate on the basis of analysis of the thermal distribution of main‐component trees in each zone. The whole and main thermal distribution ranges for 73 tree species were obtained from their distributions along the warmth index (WI) gradicnt. Cluster analysis using the WI values at the upper and lower limits of the main distribution ranges as parameters gave seven species groups. The geographical distributions of the species in each group were described. Moreover, the frequency distribution curves of the seven species groups were determined along the WI grandient, and four borderlines (lines I, II, III and IV) were found among them. The WI values at the lines I, II and IV were 50, 90, 175°C month, respectively, and corresponded to boundaries between the subarctic and cool‐temperate zones (I), the cool‐and warm‐temperate zones (II) and the warmtemperated and subtropical/tropical zones (IV), respectively. Line III corresponded to a WI of 135°C month. The WI values at the forest limit and at the lower limit of the subarctic forest were estimated, and their averages were 15.2 and 49.6°C month, respectively. In conclusion, thermal climatic zones in China could be divided by the following WI values: alpine (arctic) zone, WI<15; subarctic zone, 15–50; cool‐temperate zone, 50–90; warm‐temperate zone, 90–175; subtropical/tropical zone >175°C month.
Throughfall, stemflow and interception of rainwater in an evergreen broadleaved forest
Authors: Masukata Hiromi , Ando Makio , Ogawa Husato 
Published: March 2006

AbstractIn order to analyze the dyanmics of heavy metals in a forest ecosystem, throughfall and stemflow were collected for individual rain showers in an evergreen broad‐leaved forest dominated by Castanopsis cuspidata. The relation between throughfall (or stemflow) (Px) and gross rainfall (P) was approximated by a linear regression equation Px=a(P‐b). The values of coefficient “a” were 0.32–2.02 for throughfall at each sampling point and the mean values for 1976 and 1977–1978 were 0.682 and 0.767, respectively. The stemflow volume differed widely among individual trees, depending mainly on the tree form of each species. In particular, the tree form of Pasania edulis was found to be especially suited to collecting stemflow. One P. edulis tree collected 64% of the rainwater that fell onto its crown as stemflow. The ratio of stemflow to gross rainfall decreased in summer resulting from an increase in leaf biomass and an increase in air temperature. In fact, the values of coefficient “a” for mean stemflow per unit area were 0.180 for summer and 0.229 for other seasons in 1976, and 0.145 for summer and 0.155 for other seasons in 1977–1978 for different sampled trees.
The role of seed dispersal and seedling traits in colonization and coexistence of Salix species in a seasonally flooded habitat
Authors: Niiyama Kaoru 
Published: March 2006

AbstractRegeneration traits of six co‐occurring Salix species were studied on a floodplain of the Sorachi River, central Hokkaido, Japan, and their colonization success and coexistence in a local habitat were discussed. Mixed Salix communities contained six Salix species; dominant:S. sachalinensis; four subordinates:S. rorida, S. pet‐susu, S. miyabeana and S. subfragilis; rare species:S. jessoensis. Their phenology, falling velocity and longevity of seeds, and the effects of microtopography and soil texture on seedling establishment were studied. The six Salix species had overlapped seed dispersal periods that coincided with the decrease of water level after a predictable spring flood. This coincidence was crucial for the colonization success because the seedlings were established on wet soils left by the decreasing water level. They showed two types of regeneration trait, specialization and generalization. S. rorida and S. subfragilis showed contrasting regeneration traits; early vs. late seed dispersal, large vs. small seeds, seedling distribution on coarse vs. fine soils, respectively. These two species rarely co‐occurred. On the other hand, the dominant S. sachalinensis had an intermediate seed size and dispersal timing, and a wide range of seedling distribution from coarse to fine soils. These results revealed that flooding seasonality influenced the colonization success together with the regeneration traits of Salix species, and that coexistence of the Salix species was facilitated primarily by regeneration niche separation related to flooding seasonality and soil heterogeneity.
Decreased reproductive rate of the spider, Nephila clavata, inhabiting small woodlands in urban areas
Authors: Miyashita Tadashi 
Published: March 2006

AbstractThe reproductive characteristics and feeding conditions of the spider, Nephila clavata, were examined at some urban and non‐urban woodland sites. More than 80% of females were gravid by late October in both non‐urban and large urban woodlands, whereas only 10%–30% were gravid in small urban woodlands. The expected number of eggs per female in mid‐October was also lower in the small urban woodlands, although body length was not reduced. This suggests that reproductive failure was not caused by food shortage during the nymphal stage. Relative food consumption rate, prey size, biomass and size of potential prey during the adult stage all tended to be lower in small urban woodlands. These results suggest that decreased reproduction of N. clavata in small urban woodlands is caused by food shortage during the adult stage, particularly a shortage of large insects.
Effects of deer browsing on the early stage of pyrogenic succession on Miyajima Island, southwestern Japan
Authors: Okuda Toshinori , Nakane Kaneyuki 
Published: March 2006

AbstractThe early stage of forest regeneration on Miyajima Island, southewstern Japan, was studied for three years after a fire in 1984, with respect to the effects of deer browsing. The regeneration patterns of woody species, in terms of the biomass increment and browsing damage to plants, were classified into the following three groups: non‐ or rarely browsed species with little increment of biomass, heavily browsed with little increment, and heavily browsed with large increment. The aboveground biomass increased from 0.4 kg to 2.7 kg per 100 m2 during three years, and was less than half of the biomass obtained in other burnt pine forests on the adjacent deer‐free islands. About 28% of the plant biomass was consumed by deer. The effects of browsing on forest regeneration were heavier at lower than that at the higher altitudes. On this island, deer browsing seems to have an important effect on vegetational succession in the burnt areas.
Growth analysis of Quercus serrata seedlings within Miscanthus sinensis grass canopies differing in light availability
Authors: Tang Yanhong , Washitani Izumi , Tsuchiya Takayoshi , Iwaki Hideo 
Published: March 2006

AbstractThe effects of different light regimes on the survival, growth and morphology of Quercus serrata seedlings were studied in canopies of Miscanthus sinensis. The seedlings of various ages (0–3 yr) were grown in three light regimes: under a dense M. sinensis canopy (TG plot) receiving 2.5%–8.7% of full sunlight, under a relatively sparse canopy (SG plot) receiving 3.8%–16.1% of light and in an adjacent open site (NG plot). There was a little difference in the survival of Q. serrata seedlings among the three plots. Height and diameter of stem and total leaf area of the seedlings were significantly lower in the shadier plots. However, the first (bottom) flush of the stem was significantly longer in the TG plot than in the NG and SG plots. Total dry weights of individual 1‐ and 2‐yr‐old Q. serrata seedlings in the TG plot were reduced to about one‐twelfth of those in the NG plot. Although the relative proportion in dry weight of each organ did not differ significantly among the plots, leaf area ratio, specific leaf area and stem height per unit dry weight were significantly higher in shadier plots. The leaf area per unit stem height was increased considerably in the sunnier plots.