bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early herbaceous succession along a topographical gradient on forest clear‐felling sites in mountainous terrain, central Japan
Authors: Ohtsuka Toshiyuki , Sakura Tsuguo , Ohsawa Masahiko 
Published: March 2006

AbstractEarly successional patterns of herbaceous communities in forest clear‐felling sites were investigated along a topographical gradient, which included ridge, slope and valley habitat types, in warm‐temperate evergreen forest regions of central Japan for 5 years. Three dominant species with wind‐dispersed seeds played a major role in the succession: an annual, Crassocephalum crepidioides, a biennial, Erigeron canadensis, and a perennial, Miscanthus sinensis. Pioneer herbs that have a seed‐bank strategy, which are common in old field succession, were not found in the mountainous sites. The persistence of the annual or biennial dominants during the very early stages of secondary succession was different in the three topographical habitat types. In the ridge habitat, M. sinensis dominated from the first year state, and C. crepidioides and E. canadensis were less prominent. Crassocephalum crepidioides and E. canadensis became dominant as one moved down the slope. In the valley habitat, C. crepidioides dominated in the first year stage, was succeeded by E. canadensis in the second year, and then M. sinensis gradually replaced it in later years. As all three wind‐dispersed dominants simultaneously invaded in all the habitat types after clear‐felling, the different successional patterns along the topographical gradient might have resulted from differences in the establishment ability and the growth rate of the three dominants depending on the three habitat types.
Stand structure and dynamics of wave‐type Abies sachalinensis coastal forest
Authors: Sato Toshihiko 
Published: March 2006

AbstractStand structure and regeneration pattern were examined in Abies sachalinensis coastal forest in northern Hokkaido. In the forest a similar phenomenon to the wave regeneration in subalpine forests has been found. Wave regeneration has been reported for montane Abies forests in central Japan and North America. Differences and similarities between wave‐type stands in this coastal forest and wave‐regenerated montane forests were clarified.The shift of dead tree zone, stand structure and regeneration pattern in wave‐type stands are the same as in subalpine wave‐regenerated forests. High density of individuals is considered to be an internal factor which causes stand‐level dieback and also enables the stands to persist in the severe environment in both forests.A difference between wave‐regenerated forests and A. sachalinensis wave‐type stands is the number of dead tree zones, which is only one in wave‐type stands. Changes of regeneration patterns of Abies sachalinensis with environmental gradient from seaward to inland were related to this difference.
Influence of vegetation and soil types on the wheatbelt termite, Drepanotermes tamminensis (Hill), in the Western Australian wheatbelt
Authors: Park H. C. , Majer J. D. , Hobbs R. J. 
Published: March 2006

AbstractA survey of the distribution and density of mounds of the harvester termite, Drepanotermes tamminensis (Hill), was carried out in the Durokoppin Nature Reserve, Western Australia in 1990. Vegetation and, to a lesser extent, soil type, appear to be important factors in determining density and distribution of termite mounds within the Reserve. A more detailed study of mounds in Wandoo (Eucalyptus capillosa) woodland and Casuarina (Allocasuarina campestris) shrubland indicated that the total number and size of mounds were significantly higher in the woodland than in the shrubland. The total wet weight biomass of D. tamminensis was calculated as 3.74 gm−2 (37.4 kg ha−1) in the woodland and 1.69 gm−2 (16.9 kg ha−1) in the shrubland. Thus, of the two favored habitats, Wandoo woodland appears to be more optimal for this termite species than the Casuarina shrubland.
Male emergence timing and mating success in the funnel‐web spider, Agelena limbata (Araneae: Agelenidae)
Authors: Masumoto Toshiya 
Published: March 2006

AbstractField observations on the relationship between male mating success and emergence timing in the funnel‐web spider, Agelena limbata, were conducted. Agelena limbata is an annual species and adult males appear slightly earlier than adult females in July. As males deposit a copulatory plug at the female epigynum after copulation, copulation with virgin females is important to males. The number of copulations in males with virgin females, which strongly correlates with the longevity of males and the number of females that males courted, did not correlate with the emergence timing of males. Early emerged males and females were significantly larger in size than later ones, but the correlation coefficient between the emerged date and the cephalothorax width was not strong. Males that emerged earlier did not have any advantage in copulating with larger and more fecund females. Furthermore, virgin females first copulated on average 7.9 days after their final molt and the mortality rate of adult males increased after the final molt. These factors may favor the smaller degree of protandry in male emergence timing in A. limbata.
Seasonal change in the food habits of the Iriomote cat Felis iriomotensis
Authors: Sakaguchi Noriaki , Ono Yuiti 
Published: March 2006

AbstractThe food habits of the Iriomote cat Felis iriomotensis were studied by analyzing 177 feces collected monthly from 1987 to 1988. A total of 26 food items were identified. The frequency of lizards and frogs in the feces was higher than those of mammals and birds. The food habits changed greatly seasonally. Eumeces skinks were fed on most frequently, and found in the feces with a similar high frequency occurrence in March–April and July–September, while their proportion to the total number of food items was larger in March–April than in July–September. The cats fed on larg‐sized skinks, adult Eumeces kishinouyei, more in March–April than in other seasons. The number of skinks sighted in the course of a road census was greater from March to August, and large‐sized skinks were sighted more in March–April than in July–August. The cats fed selectively on large‐sized skinks in every season. Therefore, changes in the food habits depended on the food availability. Characteristics of food habits in the Iriomote cat are discussed in comparison with the food habits of other felids in temperate and tropical regions.
Optimal strategy of plant antiherbivore defense: Implications for apparency and resource‐availability theories
Authors: Yamamura Norio , Tsuji Nobuyuki 
Published: March 2006

AbstractPlants produce chemicals as methods against animal herbivory. Such chemical defenses are classified into two major categories: (i) quantitative defenses with massive production of indigestible substances; and (ii) qualitative defenses with production of poisonous substances. A mathematical model was developed that identified factors that favored the evolution of quantitative defenses. Selecting an annual plant for simplicity, the allocation of photosynthetic production between growth substances and defense substances was considered. If the plant invests more in defense substances, it can protect itself more efficiently from herbivory but with a reduced growth rate. If it invests more in growth substances, the contrary holds. Using Pontoryagin's maximum principle, the following results were obtained: (i) the plant should conduct quantitative defenses when the growth rate (G), reflecting resource‐availability, is low and the growth period (T) is long as well; (ii) if the plant invests in quantitative defenses, the optimal proportion of defense substances (χ*) should be higher as G is smaller, but it is independent of T; and (iii) the value of χ* is not monotone for the effectiveness of defense substance (A), but has a maximum at an intermediate value of A. Predictions of the model partly supported both Feeny's apparency theory, claiming that apparent plants or their parts for herbivores should quantitatively defend themselves, and Coley's resource‐availability theory, claiming that plants with rich resources should invest in growth rather than defense.
Population dynamics of the whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), in Java, Indonesia, with special reference to spatio‐temporal changes in the quantity of food resources
Authors: Hirano Kohji , Budiyanto Erma , Swastika Nyoman , Fujii Koichi 
Published: March 2006

AbstractSix monitoring plots were established in the northern part of West Java, Indonesia, to clarify the factors that influence population fluctuations of the whitefly, Bemisia tabaci. Yellow sticky traps were used to monitor adult populations. To examine the relationship between the population fluctuations and the quantity of food resources, the quantity of food resources of B. tabaci (i.e. soybean and mung bean) was also investigated routinely in each subdistrict where the experimental plot was located. The maximum number of adults per trap in each sowing season showed a similar noticeable seasonal trend in all experimental plots. Climatic factors did not have a major role to play in population fluctuations. The number of adults per trap in each experimental plot tended to increase when the quantity of food resources in each subdistrict increased. The changes of the quantity of food resources seemed to influence the population fluctuations. It is suggested that the operation of regulatory processes in population density is influenced largely by both the distance between habitat patches and the amplitude of temporal fluctuations of the quantity of food resources. An explanation for why the time lag between fluctuations of the quantity of food resources and the number of individuals of B. tabaci occurred is discussed. Based on their flight ability and intrinsic rate of natural increase, B. tabaci is considered not to be a serious pest in the environment where the host plants are grown discontinuously in time and space.
Root respiration rate before and just after clear‐felling in a mature, deciduous, broad‐leaved forest
Authors: Nakane Kaneyuki , Kohno Takahiro , Horikoshi Takao 
Published: March 2006

AbstractSoil respiration was measured throughout the year (June 1992 to May 1993) in a mature, deciduous, broad‐leaved forest and an adjacent, clear‐felled stand which was made in November 1991, in Hiroshima Prefecture, west Japan. The same soil temperature and soil moisture content as those in the forest stand were maintained in two frame boxes covered with sheets of white netting in the clear‐felled stand to observe soil respiration. A herbicide was applied to the cut end of all stumps in one of the two frame boxes in order to kill the root system. There was no significant difference in the aboveground biomass and soil environmental conditions between the forest and the frame boxes in the clear‐felled stands. The difference in soil respiration rate between the forest and the frame box, in which the root system was killed by the herbicide, was considered to be due largely to the contribution of root respiration. Taking into consideration CO2 evolution due to the decomposition of roots killed and the change in A0 layer respiration rate after clear‐felling, the proportion of root respiration to the total soil respiration before clear‐felling was estimated to be 51% annually, which coincides closely with those values estimated previously in mature forests by other methods. The difference in the soil respiration rate between the two frame boxes (one with killed roots and the other with undisturbed roots) suggested that the annual root respiration rate just after clear‐felling dropped to about two‐thirds (70%) of that before clear‐felling.
Comparisons of nutrient recovery and specific leaf area variation between Carex lasiocarpa var. occultans and Carex thunbergii var. appendiculata with reference to nutrient conditions and shading by Phragmites australis
Authors: Onimaru Kazuyuki , Yabe Kazuo 
Published: March 2006

AbstractThe distribution of two sedge species was studied in two mires which differ in abiotic environments and in distribution of Phragmites australis. Carex lasiocarpa var. occultans dominated in nutrient‐poor valley mire, and Carex thunbergii var. appendiculata dominated in nutrient‐rich flood plain subject to water fluctuations. Phragmites australis grew well in nutrient‐rich conditions. The distribution of C. lasiocarpa showed a strong negative correlation with P. australis coverage, whereas C. thunbergii coverage was not affected by P. australis. The leaf area per dry leaf mass (specific leaf area: SLA) of C. thunbergii increased with shading by P. australis, but that of C. lasiocarpa was stable. The SLA flexibility of C. thunbergii to light interception might enable this species to invade P. australis patches in nutrient‐rich environments. The residual nutrient ratio of nitrogen and phosphorus (the ratio of the residual nutrient content at the end of the growing season to peak nutrient content) in the vegetative ramet of C. thunbergii was 1.7 times higher than that of C. lasiocarpa. This low residual ratio may indicate effective nutrient recovery to storage organs. The effective nutrient recovery in C. lasiocarpa might enable this species to grow even in nutrient‐poor environments. However, it may be difficult for C. lasiocarpa to expand its habitat to nutrient‐rich areas where P. australis dominates as it is not shade tolerant.
Culm recruitment, dry matter dynamics and carbon flux in recently harvested and mature bamboo savannas in the Indian dry tropics
Authors: Tripathi S. K. , Singh K. P. 
Published: March 2006

AbstractCulm recruitment, standing crop biomass, net production and carbon flux were estimated in mature (5 years after last harvest) and recently harvested bamboo (Dendrocalamus strictus (Roxb.) Nees) savanna sites in the dry tropics. During the 2 study years bamboo shoot recruitment was 1711–3182 and 1432–1510 shoots ha−1 in harvested and mature sites, respectively. Corresponding shoot mortality was 66–93% and 62–69%, respectively. Total biomass was 34.9 t ha−1 at the harvested site and 47.4 t ha−1 at the mature site. Harvesting increased the relative contribution of belowground bamboo biomass. Annual litter input to soil was 2.7 and 5.9 t ha−1 year−1 at the harvested and mature sites, respectively. The bulk of the annual litterfall (78–88%) occurred in the cool dry season (November to February). The mean litter mass on the savanna floor ranged from 3.1 to 3.3 t ha−1; at the harvested site wood litter contributed 70% of the litter mass and at the mature site leaves formed 77% of the litter mass. The mean total net production (TNP) for the two annual cycles was 15.8 t ha−1 year−1 at the harvested site and 19.3 t ha−1 year−1 at the mature site. Nearly half (46–57%) of the TNP was allocated to the belowground parts. Short lived components (leaves and fine roots) contributed about four‐fifths of the net production of bamboo. Total carbon storage in the system was 64.4 t ha−1 at the harvested site and 75.4 t ha−1 at the mature site, of which 23–28% was distributed in vegetation, 2% in litter and 70–75% in soil. Annual net carbon deposition was 6.3 and 8.7 t ha−1 year−1 at harvested and mature sites, respectively.
Nitrogen translocation via rhizome systems in monoclonal stands of Reynoutria japonica in an oligotrophic desert on Mt Fuji: Field experiments
Authors: Adachi Naoki , Terashima Ichiro , Takahashi Masayuki 
Published: March 2006

AbstractMechanisms which enable Reynoutria japonica, a dominant pioneer herb, to be successful in maintaining large stands in an oligotrophic volcanic desert on Mt Fuji were investigated with special reference to its nitrogen acquisition. Reynoutria japonica forms circular stands, each of which comprises only one genet. As a stand develops outwards, the number of aerial shoots per unit area decreases in the center. Shoots grow vigorously in the peripheral area where the available nitrogen from soil and precipitation (about 2.4 g m−2 year−2) was much less than total nitrogen in the shoots (6.1–9.1 g m−2). Leaf nitrogen content per unit mass was also greater in the leaves of the peripheral shoots. When rhizomes extending radially from the center to the periphery were severed, the dry mass of shoots in the periphery diminished by 75% on a ground area basis. In the periphery, leaf nitrogen content also reduced significantly and no flowers were produced. When fertilizer was applied to the peripheral shoots with severed rhizomes, neither growth, survival nor flower production of the shoots was significantly smaller than the control levels. In these shoots, it is also found that the nitrogen content in the youngest leaves decreased for about 1 month and then increased to above that in the control leaves. These results suggest that (i) nitrogen accumulated in the central part is translocated to peripheral shoots via rhizomes, and that long‐distance translocation enables the stands to develop outwards, and (ii) aerial shoots in the periphery utilize the nitrogen translocated by rhizomes in the beginning of the growth season, whereas once the shoots have established, they begin to take up nitrogen with their own roots. Since the peripheral shoots are in sunnier environments than the shoots inside the stand, the acropetal nitrogen translocation via rhizomes will raise the production efficiency of a whole stand.
Adaptation of stomatal response of Camellia rusticana to a heavy snowfall environment: Winter drought and net photosynthesis
Authors: Kume Atsushi , Tanaka Chikako 
Published: March 2006

AbstractThe adaptation of Camellia rusticana, an evergreen broad‐leaved shrub found in areas of heavy snowfall in Japan, to heavy snowfall environments, and the mechanisms by which it is damaged in winter above the snow, were investigated. The stomatal response and photosynthetic characteristics of C. rusticana were compared to those of Camellia japonica found in areas of light snowfall. In field conditions, the mean net photosynthesis of C. rusticana at photon flux density (PFD) over 200 μmol m−2s−1 (Pn(>200). was 50% larger than that of C. japonica, but in both light saturated and CO2 saturated conditions, the O2 evolution rate (Pc) of C. rusticana was not different from that of C. japonica. Mean leaf conductance at PFD over 200 μmol m−2s−1 (gl(>200)) was about 100% larger than that of C. japonica in the field. The Pn(>200)) was 50% ratio of C. rusticana was 37% higher than that of C. japonica which suggests that C. rusticana's larger Pn(>200) can be explained by its larger gl(>200). When C. rusticana trees wintering underneath the snow were projected above it, the leaves of these plants showed serious drought within five days in non‐freezing conditions. Their Pc and the maximum stomatal conductance decreased by half and did not recover. The leaves of C. rusticana showed larger gl(>200) and a less sensitive stomatal response to the decrease of leaf water potential than that of C. japonica. The stomata characteristics of C. rusticana caused larger net photosynthesis than that of C. japonica during the no snow period, and caused the need for snow cover in winter as protector from winter drought.
Carbon dioxide evolution of an upland rice and barley, double cropping field in central Japan
Authors: Nakadai Toshie , Koizumi Hiroshi , Bekku Yukiko , Totsuka Tsumugu 
Published: March 2006

AbstractCarbon dioxide evolution rates from a double cropping, upland rice and barley field were determined in central Japan from June 1992 to May 1994, and regression models were developed to predict soil respiration rate. Diurnal patterns of hourly soil respiration rates (SRh) showed a similar trend with those of soil surface temperatures. Daily soil respiration rate (SRd) obtained by integrating SRh varied from 0.3 to 15.6 g CO2m−2for the 2 years. In the summer cropping period, SRd was positively correlated with daily mean soil surface temperature and negatively correlated with volumetric water content in soil. Moreover, this relationship was able to be expressed as a multiple‐factor model with an Adj‐R2of 0.925. On the other hand, in the winter cropping period, SRd was able to be represented by a single factor model using soil surface temperature with an Adj‐R2of 0.854. Based on these relationships, seasonal changes in soil respiration rate were estimated. Total soil respiration rates in 1992 and 1993 estimated for the summer cropping period were 1260 g CO2m−2and 1094 g CO2m−2, and for the winter cropping period 624 g CO2m−2and 676 g CO2m−2, respectively. It was considered that the lower values during the summer cropping period in 1993 depended on lower soil surface temperature and higher soil water content.
Optimal brood size and its limiting factors in the Rufous Turtle Dove Streptopelia orientalis
Authors: Kameda Kayoko 
Published: March 2006

AbstractOptimal brood size and its limiting factors of the Rufous Turtle Dove, Streptopelia orientalis, were studied at the campus of the University of Tsukuba, Japan, during the breeding season in 1990–92. The dove usually lays two eggs in a nest. I made nests of a brood size of one and three by transferring a hatchling from one nest to the other, and compared their fledging success, factors of breeding failure, weight and tarsus length at fledging, growth rate and nestling period with those of a brood of two. The index of fitness (fledgling weight multiplied by average number of fledglings per nest) was almost the same in broods of two and three. However, the highest variation in fledging weight within the brood and the extension of nestling period were observed in broods of three, which caused the extension of inter‐brood interval and consequently the smaller number of broods in the total breeding season. Therefore, broods of three would not have an advantage in producing more offspring than broods of two. Crop milk production had an effect on the growth of nestlings in the early phase of the nestling period, but the rapid growth in the granivorous phase compensated for the growth delay of the smallest nestling in broods of three. Small brood size and a large number of broods in a season would also be more effective under high predation pressure.
Ecological relationships between seedling emergence and litter cover in the earliest stage of plant succession on sandy soil
Authors: Nakamura Toshihiko 
Published: March 2006

AbstractThe relationships between seedling emergence and litter cover were studied in the earliest successional stage of a plant community. During a period of 3 years, changes in vegetation cover and species composition were assessed on three permanent quadrats with virgin sandy soil substrates A successional pattern from summer annual grasses to winter annual herbacoeus plants to biennial and perennial plants was confirmed, and invasion and replacement of the component species were conspicuous. The spatial distributions of seedlings and litter were heterogeneous in winter, and some patches consisting of both seedlings and litter were observed. There was a strong positive correlation between distribution patterns of seedlings and litter; seedling density increased with increasing litter cover. The results suggest that the litter cover of the previous stage plays an imporrant role in promoting successional changes in the early stage of plant succession.