bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stand structure and growth patterns of understorey trees in a coniferous forest, Taisetsuzan National Park, northern Japan
Authors: Kubota Yasuhiro , Konno Yasuo , Hiura Tsutom 
Published: March 2006

AbstractStand structure was studied with special reference to growth and mortality patterns of sapling and understorey trees in a coniferous Picea jezoensis and Abies sachalinensis forest in Taisetsuzan National Park, Hokkaido, northern Japan. Picea jezoensis was dominant in the basal area, while A. sachalinensis was abundant in large numbers in the canopy. Estimated mortalities increased significantly with diameter at breast height (DBH) for both P. jezoensis and A. sachalinensis in the canopy, but the tendency was different between the two species. Picea jezoensis had a lower mortality rate than A. sachalinensis, especially at small DBH classes. The spatial distribution of understorey individuals of A. sachalinensis did not show any significant correlation with the spatial distribution of canopy gaps, but that of P. jezoensis showed a significant correlation. Abies sachalinensis can grow higher than P. jezoensis under suppressed conditions; while P. jezoensis requires canopy gaps for steady height growth. This growth pattern leads to a different waiting height in the understorey (≥2 m in height and 10 cm in diameter at breast height). Abies sachalinensis waited for an improvement in light conditions at higher strata (max. 7 m), while P. jezoensis waited at lower strata (max. 3 m). The estimated mortality of understorey A. sachalinensis increased with size, while that of understorey P. jezoensis decreased. Therefore, P. jezoensis gives priority to survival while A. sachalinensis gives priority to understorey growth. The difference in the ‘waiting pattern’ between the two species in the understorey was considered a significant feature for the canopy recruitment process of P. jezoensis and A. sachalinensis.
Contribution of the Western Australian wheatbelt termite, Drepanotermes tamminensis (Hill), to the soil nutrient budget
Authors: Park H. C. , Majer J. D. , Hobbs R. J. 
Published: March 2006

AbstractThe role of soil modification by the mound‐building termite, Drepanotermes tamminensis (Hill), was studied during 1991 in the Durokoppin Nature Reserve, Western Australia. Soil chemical parameters were quantified for ‘soils’ in nests and for surrounding soil in both a Wandoo (Eucalyptus capillosa) woodland and a Casuarina (Allocasuarina campestris) shrubland plot. All ‘soils’ in nests were more acidic than the surrounding soil within each study plot. Generally, nutrient levels in the nested soils were higher than the un‐nested soil within each study plot and were also higher in the woodland than in the shrubland plot. Depending on the nuttient concerned, the nested soil contained between 0.3 and 21.9% of the total nutrient load per hectare within each study plot. The quantities of nutrients per hectare in termite mounds were higher in the woodland than in the shrubland plot. It is concluded that mounds of this species of termite form a significant bank of nutrients, although time for release of such nutrients depends on the degree of erosion and on the longevity of mounds.
Reproductive ecology of three ocypodid crabs II. Incubation sites and egg mortality
Authors: Henmi Yaushisa 
Published: March 2006

AbstractMortality of eggs during incubation was estimated for three ocypodid crabs, Scopimera globosa, Ilyoplax pusillus and Macrophthalmus japonicus, and the influence of incubation sites was discussed. These crabs all lived in isolated burrows and fed on sediments during day time low tide. S. globosa and I. pusillus inhabited the upper intertidal sandflats, whereas M. japonicus inhabited the lower intertidal mudflats. Females of both S. globosa and I. pusillus remained in their plugged burrows without feeding throughout incubation and the mortality of eggs was low despite large broods relative to body size. On the other hand, females of M. japonicus fed actively on surface mud during incubation and the mortality of eggs was high despiite small broods relative to body size. In S. globosa and I. pusillus, the ovaries of ovigerous females were small until egg‐hatching, whereas in M. japonicus, the ovaries grew rapidly during incubation and females were able to produce consecutive broods. I conclude that incubation of eggs in burrows may be advantageous in species which inhabit the upper interidal sandflats, even though the crabs cannot forage during incubation, since otherwise their eggs would be exposed to strong heat stress and desication during the summer. Furthermore, such species may produce few large broods because of less frequent interruption of feeding than that associated with production of many small broods.
Carbon‐cycling changes during regeneration of a decinduous broadleaf forest after clear‐cutting II. Aboveground net production
Authors: Kawaguchi Hideyuki , Yoda Kyoji 
Published: March 2006

AbstractGrowth and death rates of aboveground plant parts were measured in a mature forest and four different‐aged deciduous broadleaf forests regeneratede after clear‐cutting, with special reference to rates for woody parts (stems and branches) of different diameters (ø) in rerms of the pipe model theory (Shinozaki et al., 1964). The total biomass increment of woody parts of trees higher than 1.3 m varied within a range of 2.1‐4.6 ton ha−1 yr−1, the increase beingdue largely to the growth of canopy trees exposed to direct sunlight. Biomass increments of small (ø<1 cm) and medium (1≤ø<5 cm) woody parts were negligibly small except in the youngest forest, and changes in aboveground woody biomass with forest age after clear‐cutting mainly resulted from accumulation of large (5 cm<ø) woody parts of canopy trees. Biomass loss of trees due to death and grazing increased with forest age from 4.0 to 8.3 ton ha−1 yr−1. Recovery of leaf and small wood falls was observed at the early stage of regeneration, while large wood falls increased during regeneration. Flower and fruit fall was markedly higher in the mature forest than in the other four forest types. Mortality of woody parts became higher with forest age and was 20, 5.0 and 0.46% yr−1 for small, medium and large parts, respectively, at the mature stage. Aboveground net production of the forest was in therange 7.6‐13.3 ton ha−1 yr−1 with the undergrowth vegetation lower than 1.3 m being 0.4‐1.4 ton ha−1 yr−1. Production recovered rapidly at an early stage of regeneration and was highest in mature forest.
Edge effects created by clear‐cutting on habitat use by sika deer on Mt. Goyo, northern Honshu, Japan
Authors: Takatsuki Seiki 
Published: March 2006

AbstractClear‐cutting increased the species diversity and amount of undergrowth plants in a habitat of Sika deer (Cervus nippon) on Mt. Goyo, northern Japan. The number of species increased from 15 to 48 as a result of clear‐cutting. Among the plants, Sasa nipponica (a dwarf bamboo), an important forage plant for Sika deer, was predominant. Fecal pellets of deer were abundant in the forest and at the “adjacent zone” (from the edge to 150 m out of the forest) and thereafter decreased suddenly. The intensity of utilization of Sasa nipponica was also heavy in the forest, moderate at the adjacent zone and light 200 m from the forest edge. Since the amount of the bamboo in the forest was small, the removal of bamboo was greatest at the adjacent zone. Clear‐cutting creates a favorable feeding area for Sika deer in this zone by increasing the available plant production and securing forest cover.
Comparative ecophysiology of Larix kaempferi (Lamb.) Carr. and Abies veitchii Lindl. II. Mechanisms of higher drought resistance of seedlings of L. kaempferi as compared with A. veitchii
Authors: Yura Hiroshi 
Published: March 2006

AbstractThe underlying mechanisms of drought resistance in seedlings of Larix kaempferi as compared with those in Abies veitchii were investigated. First, seedlings of the two species were desiccated in air of differing water potential, and their survival rates were compared to detect any difference in desiccation tolerance between them. Contrary to differences in their drought resistance, A. veitchii showed higher survival. Next, the shoot heights and root depths of the two species were compared to detect any difference in desiccation avoidance. Although the shoot height differed little between the two species, the roots of L. kaempferi seedlings were much deeper than those of A. veitchii seedlings, and the death rate under progressing drought was well correlated with the root extensibility of each species. It was thus concluded that L. kaempferi seedlings are able to avoid desiccation by extending their roots in deep soil faster than A. veitchii seedlings, thereby resisting to drought.
How to avoid becoming a prey: Predatory encounters between an orb‐weaving spider, Araneus pinguis (Karsch) (Araneae: Araneidae) and flying insects
Authors: Endo Tomoji 
Published: March 2006

AbstractInsects flying into the web of an orb‐weaving spider Araneus pinguis (Karsch) and their avoidance of (pre‐hitting process) and escapes from (post‐hitting process) the web were examined by direct observation under natural and semi‐natural conditions. In the pre‐hitting process, mobile insects such as Brachycera, Lepidoptera and Hymenoptera showed a low hitting ratio (number of insects hitting/number of insects flying within 1 m3 space around the web‐site) because of active web avoidance and flying activity in layers lower or higher than those in which the webs are usually laid. In contrast, less mobile insects like Heteroptera, Coleoptera and Homoptera showed a high hitting ratio. In the post‐hitting process, Brachycera, Lepidoptera and some Nematocera frequently escaped without being detained by the web. Many Orthoptera and Hymenoptera escaped without any sign of detection by the spider. Coleoptera frequently escaped during the spider's attack. Small insects from the Homoptera, Nematocera and Hymenoptera rarely escaped from the web, but were not immediately attacked. Mean escape time of insects was correlated significantly with capture success of the spider. Overall most of the escapes occurred in the early phases of the predation process. This indicates that escapes are unlikely to result in heavy loss of time and energy expenditure due to unsuccessful predation. Escape patterns of insects seem to be related to their mobility.
An analysis of age‐and size‐dependent flowering: A critical‐production model
Authors: Yokoi Yota 
Published: March 2006

AbstractThree critical phenomena of flowering can be recognized in nature: critical age, critical initial size and critical switchover size. In order to understand the ecological significance of these flowering phenomena from the viewpoint of matter production, a simple model of flowering phenomean (critical‐production model) was studied, assuming that plant flowering is controlled by the productive capacity of the plant (critical‐production model, under the condition that plants forecast environmental conditions affecting matter production. Thus, we concluded that all three critical phenomena are various manifestation of the same critical‐production principle. Then, using the model simulation, the reliability of each critical phenomenon for securing a given critical production was investigated in relation to the photosynthetic productivity of the habitat. The main predictions obtained from the simulation were as follows: 1) Only annual and biennial plants will show critical age phenomena, and most biennials will be facultative. 2) Among perennials, the critical initial size phenomenon will appear in low productive habitats, whereas in high productive habitats the critical switchover size phenomenon will be observed.
Parasitoid complexes of lepidopteran leaf miners on oaks (Quercus dentata and Quercus mongolica) in Hokkaido, Japan
Authors: Sato Hiroaki 
Published: March 2006

AbstractParasitoid complexes of four microlepidopteran leaf‐mining genera, Phyllonorycter, Caloptilia (Gracillariidae), Tischeria (Tischeriidae) and Stigmella (Nepticulidae), which make mines on two oaks, Quercus dentata and Quercus mongolica, were studied at the Ishikari Coast, Hokkaido, northern Japan. In total, twenty‐five parasitoid species were recognized. Phyllonorycter showed the highest parasitoid‐species richness among the four leaf‐mining genera. The number of parasitoid species associated with leaf miners on Q. dentata was nearly equal to that associated with miners on Q. mongolica, but a considerable difference was observed in the faunal make‐up of parasitoids between leaf miners on the two oaks. The dominant parasitoid species differed between Phyllonorycter leucocorona and Phyllonorycter similis even on the same oak, Q. dentata. Factors influencing the host ranges of parasitoids and the parasitoid richness of host species or genera are discussed on the basis of the koinoparasitism/idioparasitism categorization.
Effects of human trampling and multispecies competition on early‐phase development of a tread community
Authors: Ikeda Hiroaki , Okutomi Kiyoshi 
Published: March 2006

AbstractEffects of human trampling and multispecies competition on the development of a tread community in the first year were examined by comparing changes in the relative abundance of three main component species of tread communities, Plantago asiatica, Eragrostis ferruginea and Eleusine indica, between monoculture and mixed culture along a trampling gradient. At low trampling levels in mixed culture, Ambrosia artemisiifolia var. elatior and Digitaria adscendens, which are common pioneer species of secondary succession, predominated and suppressed the tread community species. Severe trampling reduced markedly the predominance of the pioneer species, but not that of the tread community species. The maximum cover of the three tread commiunty species was lower in mixed culture than in monoculture. The trampling levels supporting the maximum cover were higher in mixed culture than in monoculture. The differences in these levels between monoculture and mixed culture varied among the three:P. asiatica< Eragrostis ferruginea<Eleusine indica. These results suggest that (1) the pioneer species interfere with the establishment of tread community species under lower trampling intensity, (2) heavier trampling reduces the competitive ability of pioneer species, while it favors the establishment of tread community species, (3), there are competitive interactions among the tread community species under higher trampling intensity, and (4) the species more susceptible to multispecies competition and tolerant to trampling are established in more heavily trampled habitats.
Estimation of chronological age for sporophyte maturation in three semi‐evergreen ferns in Hokkaido
Authors: Sato Toshiyuki 
Published: March 2006

AbstractTo elucidate the life cycle time schedule of semi‐evergreen ferns at natural sites in Sapporo, the chronological age for sporophyte maturation was estimated from the increase in the number of veins (NV, number of midrib branches) from overwintered to newly expanded leaves. The measurements were conducted on populations of Polystichum braunii, Polystichum tripteron and Dryopteris crassirhizoma at altitudes of 50–650 m on Mt. Teine to compare the interspecific maturation age of sporophytes. The mean age for sporophyte maturation was estimated to be 7.6 yr for P. braunii, 16.5 yr for P. tripteron and 12.6 yr for D. crassirhizoma. The minimum ages (1% fertility rate) for sporophyte maturation of P. braunii, P. tripteron and D. crassirhizoma were 5.8, 11.0 and 7.9 yr, respectively. The maturation age was shortest for P. braunii and longest for P. tripteron. The maturation age of a species thus seems to differ according to altitude and habitat, and that of the present three species seems to be influenced by the geographical location of the species distribution.
Nutrient dynamics in a floating mat and pond system with special reference to its vegetation
Authors: Haraguchi Akira , Matsui Kiyoshi 
Published: March 2006

AbstractChemical properties of waters and their seasonal changes were studied in Mizorogaike Pond, a system of pond and floating mat. The following six sites including contrasting habitats and water conditions were monitored to assess nutrient dynamics in the system: 1) a pool on the mat, 2) margin of a Sphagnum cuspidatum community, 3) an artificial ‘well’ (water layer beneath the floating mat), 4) a Menyanthes trifoliata community in a hollow, and 5) & 6) two sites in the open water. On the floating mat, the water around the Sphagnum community had lower pH values, while that in the M. trifoliata community had higher pH values. This difference was related to the influence of flood water, the extent of which was determined by the microtopography. Seasonal changes in water chemistry on the mat suggested that pond water flooding the mat in late autumn and winter is important for the nutrient supply to the mat surface vegetation in this system. Water chemistry of the ‘well’ suggested that the diffusion of inorganic nitrogen occurs from beneath the peat layer. Two types of cluster analysis based on the mean values for chemical variables and the patterns of fluctuation in these variables were performed. The six sites were classified into similar groups which were identified by water type (pool, hollow, well and open water) by both types of analysis. The results showed that a common kind of perturbation should operate in determining the status of nutrient dynamics in the various water types.
Vegetation changes around the last glacial maximum and effects of the Aira‐Tn ash, at the Itai‐Teragatani site, central Japan
Authors: Oor Nobuo , Minaki Mutsuhiko , Noshiro Shuichi 
Published: March 2006

AbstractOn the basis of fossil pollen, plant macrofossils and fossil wood, vegetation existing around the Itai‐Teragatani Site between 26000 and 20000 yr ago was reconstructed. On the upland, there were mixed forests of conifers and deciduous broad‐leaved trees throughout the studied period. The forests consisted mainly of Pinus subgen. Haploxylon and Quercus subgen. Lepidobalanus, together with Tsuga, Cryptomeria and Ulmus‐Zelkova. In the wetland, there were stands of Betula and Alnus in grassland consisting of Cyperaceae, Gramineae, Lysichiton, Thalictrum, Sangusiorba, Umbelliferae and Compositae. The vegetation changed three times during the studied period. The first change, which occurred prior to the fall of the Aira‐Tn ash, was characterized by an increase in Abies, Pinus subgen. Haploxylon and hygrophytes, and a decrease in Cryptomeria and Alnus. This is considered to reflect a cooler climate, and expansion of grassland. The second change was caused by the fall of the Aira‐Tn ash, which caused serious damage to the vegetation. Many taxa, except for Alnus, Cyperaceae and Lysichiton, decreased or vanished after the ash fall. The third change was the process of recovery after the damage. The regenerated forests differed from those before the ash fall. With the regeneration conifers and Artemisia increased. This seemed to reflect the changes in climate and ground conditions caused by the accumulation of the ash.
Estimation of leaf area at the level of branch, tree and stand in Cryptomeria japonica
Authors: Katsuno Masumi , Hozumi Kazuo 
Published: March 2006

AbstractThe frequency distribution of diameter (x) in foliage shoot segments, ø(x), was examined in 18 branches at different height levels of three trees in a 25‐yr‐old sugi (Cryptomeria japonica D. Don) plantation. The ø‐x relationships were approximated by power‐form equations, in which the exponent differed among the branches from −0.6 to −4.2. Leaf area (SB) and leaf weight (WB) of a branch were estimated on the basis of the ø‐x relationship, and the dependency of specific leaf area (SLA0) and density (ρ0) of a foliage shoot segment on its x. SLAB value of a branch defined by SB/WB ranged from 27 to 80 cm2 g. d.w.−1 according to the exponent in the function of ø(x). Total leaf area (u) and leaf weight (wl) of a tree were estimated by summation of SB and WB for seven sample trees. The SLAT value of a tree defined by u/wl ranged from 65 to 76 cm2 g d.w.−1 and increased with stem diameter at clear length (DB). By use of the allometric equations between u and DB, LAI of the plot was estimated to be 17.3 ha ha−1 (half of the total surface area of needles). By a process similar to that used for calculating LAI, the amount of woody tissues included in sugi foliage was evaluated to be about 10% of the stand foliage biomass.
Dynamics of aboveground big woody organs in a foothill dipterocarp forest, West Sumatra, Indonesia
Authors: Yoneda Tsuyoshi , Tamin Rusdij , Ogino Kazuhiko 
Published: March 2006

AbstractThe dynamics of aboveground big woody organs over 10 cm diameter was studied at a mature foothill dipterocarp forest in West Sumatra. The biomass of big woody organs was estimated to be 519 m3 ha−1 or 408 metric ton ha−1 by means of a pipe model theory. The diameter distribution showed a convex curve and the mode was found at a diameter of about 20 cm. The standing mass of big dead woody litter on the forest floor was 116 m3 ha−1, which accounted for 22% by voume or 9.5% by weight of the biomass of living organs respectively. The dbh observation with two 1‐ha plots for 4 yr and 5 yr respectively revealed that the average net production rate was 9.5 ton ha−1 yr−1. The death rate (7.9 ton ha−1 yr−1) accounted for 83% of the net production rate and was nearly equivalent to the decay rate (7.5 ha−1 yr−1) of dead wood on the forest floor. The balance between the death and decay rates was confirmed for each diameter class. Average turnover periods for big woody organs and dead woody litter were estimated to be 43 and 8.1 yr, respectively. Standing masses of live anddead woody materials accumulated in the study forest were approximately equal to those obtained in a mature tropical lowland rainforest, whereas the flow rates were lower, being only 70% of the corresponding values.
Optimal time of seedling emergence in a dune‐population of Oenothera glazioviana
Authors: Kachi Naoki , Hirose Tadaki 
Published: March 2006

AbstractOenothera glazioviana (= O. Erythrosepala) behaves as a facultative biennial in an infertile sand‐dune system in Japan. In the field, seedlings emerge mainly in autumn following seed ripening in late summer with an additional small peak in spring. The effects of emergence time on subsequent survival and fecundity, and the ultimate numbers of seeds produced per emerging seedling (Fs) were examined by a demographic model. The model showed that seedlings emerging either in March or in September–October will attain higher Fs than those emerging in other months. If mortality in the seed bank is taken into account, autumn seems to be the best season for emergence to maximize the number of seedlings in the next generation.