bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of herbivore density on host plant mediated interactions between two insects
Authors: Masters Gregory J. 
Published: March 2006

AbstractRecent work suggests that foliar‐ and root‐feeding insects can interact in a novel plus‐minus fashion. However, the effects of herbivores may be different at different densities. This paper describes two laboratory experiments investigating the effect of increasing insect density on plant performance and the host‐plant mediated interaction between a leaf‐mining fly and root‐feeding chafer larvae. Above‐ and below‐ground insect herbivory decreased plant performance. The effects of the root feeder were, for some parameters, different between the two densities of chafer larvae. Leaf mining significantly decreased the performance of the chafer larvae, while root herbivory was found to increase the pupal weight (related to fecundity) of the leaf miner. The effects of root herbivory suggest that the relationships between herbivore density and plant performance may be curved as the greater chafer density had no significant increased effect on the plants or foliar‐feeding insects.
Shoot growth phenology of co‐existing evergreen and deciduous species in an oak forest
Authors: Dhaila S. , Singh S. P. , Negi G. C. S. , Rawat Y. S. 
Published: March 2006

AbstractShoot growth phenology was compared for the saplings of evergreen and deciduous woody species sharing the same microsite. Growth initiation occurred earlier in evergreens (among co‐stratal species) while deciduous species completed their growth earlier. Shoot growth rate was significantly greater (P<0.01) for deciduous trees than evergreen trees. The amount of shoot elongations and shoot diameter was also significantly greater (P<0.01) for deciduous trees than evergreens. On the other hand, among shrubs the amount of shoot elongation and shoot diameter was greater for evergreens but the rate of elongation and diameter was more or less similar for both. The duration of shoot elongation and shoot diameter was significantly longer in evergreens than the deciduous species. Leaf packing (number of leaves per shoot) was significantly more dense in evergreen trees (P<0.01) than in deciduous tree species. Leaf packing was more dense in evergreen than deciduous shrubs but the difference was not significant. Leaf area (per individual leaf) at full expansion was significantly greater (P<0.01) in deciduous species. Leaf dry mass and specific leaf mass in the initial stage was significantly greater for evergreen species than for deciduous species. The number of buds/10 cm of shoot was higher in evergreens. However, the per cent mortality was also higher in them.
Characteristics of small‐scale heterogeneity in light availability within a Miscanthus sinensis canopy
Authors: Tang Yanhong , Washitani Izumi 
Published: March 2006

AbstractTo examine the small‐scale variations in light and space availability, photon flux density (PFD) at 20 cm aboveground was measured at 2 cm intervals along each of four 160 cm horizontal transects under an overcast sky condition in a Miscanthus sinensis Anderss grass canopy. Two characteristics were identified for the variation patterns of PFD penetration along transects; the predominant variations of PFD penetration prevailed at the scales usually larger than 10 cm, and the point‐to‐point fluctuations occurred everywhere. Spatial autocorrelation coefficients of PFD penetration along transects were highly positive (>0.5) over the lag distances from 2 to 6 cm, while those of the point‐to‐point fluctuations exhibited a random series. Spectrum analysis showed a higher spectrum density at the lower frequency, that is, at the higher periodicity, which indicated that the variation of PFD penetration was mainly due to the patchy distribution of grass canopy. PFD‐available spans along the transects and contour maps were examined to evaluate the microsites fulfilling both PFD and space requirements in the growth of Quercus serrata Thunb. seedlings. More than 75% of the spans with PFD penetration constantly exceeding 0.04 were shorter than 8 cm, which suggests that a large proportion of high PFD spots may not be used by Q. serrata seedlings in the grass canopy because of the limitation of availability in space. The spatial heterogeneity of PFD at small scales may be of great importance in the succession of M. sinensis grass communities.
Ontogenetic niches of a planktonic copepod in Lake Biwa studied on a fine temporal scale
Authors: Kawabata Keiichi 
Published: March 2006

AbstractEodiaptomus japonicus was collected in the north basin of Lake Biwa, Japan, on six dates from 11 to 25 June 1987. Temporal changes in its vertical distribution and reproduction indices were small, but those in its abundance were large. Mortality was high in the naupliar stage I and from copepodid stage III to adult stage. The latter fact and low proportion of females in adulthood suggest heavy predation by fishes which prefer larger prey. Eodiaptomus japonicus showed ontogenetic vertical migration within the epilimnion. The direction of the migration was upward in the early naupliar stages and downward in the late naupliar and early copepodid stages. Both migrations resulted in raising mortality in the corresponding or succeeding stages, probably expressing the behavioral constraints of E. japonicus.
Age‐sex differences in the diets of Sika deer on Kinkazan Island, northern Japan
Authors: Padmalal U. K. G. K. , Takatsuki Seiki 
Published: March 2006

AbstractDietary differences in the ages and sexes of Sika deer (Cervus nippon) were studied on Kinkazan Island, northern Japan from October 1990 to July 1991. Larger deer consumed more graminoids than smaller deer except in spring, and less dicotyledonous leaves in all the seasons. Fecal nitrogen concentrations were lower in larger deer than in smaller deer in all the seasons. The age‐sex differences in foods were smaller in summer and winter when foods were most abundant and scarce, respectively, while they were greater in spring and autumn when food availability was intermediate.
Maximum yield and the C‐D effects in natural white birch stands
Authors: Shibuya Masato 
Published: March 2006

AbstractThe competition‐density effect for natural Japanese white bitch (Betula platyphylla var. japonica) stands, located in the northern part of Hokkaido Island, was examined for various growth stages to establish mean tree weight‐density relationships over a considerable extent of stand growth of white birch. Aboveground yields of investigated stands ranged from 16.0 to 161.7 t·ha−1, and it was recognized that maximum aboveground yield of this species was about 160 t·ha−1. Constants A and B of the reciprocal equation of the C‐D effect, 1/w=AN+B (w, mean tree weight; N, tree density), were related to mean height classes of birch stands. Constant B was related to the entire mean height classes as the allometric relationship. On the other hand, constant A had an allometric relationship to mean height classes under 16 m, but became fixed over the 16 m class. White birch stands can come up to the maximum yield approximately at the stage of the 16 m class. The asymptotic tendency seemed to be appropriate for constant A‐mean height class relationship. The maximum yield of white birch stands was predicted by the asymptotic value of A. The trend of mean tree weight‐density relationships with stand growth also changed with constant A. It was considered that maximum yield was an important characteristic for practical applications of the C‐D effect to agriculture and forestry.
Efflux of carbon dioxide from snow‐covered forest floors
Authors: Mariko Shigeru , Bekku Yukiko , Koizumi Hiroshi 
Published: March 2006

AbstractThe release of CO2 from the snow surface in winter and the soil surface in summer was directly or indirectly measured in four cool‐temperate deciduous broadleaved and evergreen needle forests. The closed chamber method (CC‐method) and Fick's diffusion model (DM‐method) were used for the direct and indirect measurements, respectively. The winter soil temperatures from the soil surface to 10 cm depth were between 0 and 2°C. The concentration of CO2 within snowpack increased linearly with increasing snow depth. The average effluxes of CO2 calculated from the gradients of CO2 concentration in the snow using the DM‐method ranged from 20 to 75 mg CO2 m−2 h−1, while the CC‐method showed the average effluxes of 20 to 50 mg CO2m−2h−1. These results reveal that the snow thermally insulates the soil, allowing CO2 production to continue at soil temperatures a little above freezing throughout the winter. Carbon dioxide formed in the soil can move across snowpack up to the atmosphere. The winter/summer ratio of CO2 emission was estimated to be higher than 7%. Therefore, the snow‐covered soil served as a source of CO2 in the winter and the effluxes represent an important part of the annual CO2 budget in snowy regions.
Arthropod communities in a Japanese cedar (Cryptomeria japonica D. Don) plantation: Abundance, biomass and some properties
Authors: Hijii Naoki 
Published: March 2006

AbstractArboreal arthropod communities were censused by insecticidal knockdown in a plantation of Japanese cedar, Cryptomeria japonica, in central Japan from April 1983 to February 1985 at intervals of two months. All arthropods sampled were allocated to higher taxonomic groups or guilds and the composition of the communities was analyzed with respect to abundance, biomass and their seasonal trends. The total densities fluctuated seasonally from 200 to 3500 m−2; corresponding biomass values ranged from 7 to 600 mg fresh weight m−2. Maximum density and biomass generally occurred in summer and were minimum in winter. The consistently dominant guild in terms of abundance were the detritivores, mostly comprising Collembola and oribatid mites, accounting for 36–93% of all arthropods; phytophages, predators and detritivores were major guilds in terms of biomass, showing average proportions of 27%, 23% and 20%, respectively.Biomass ratios of predators to prey were generally high in some canopy communities, suggesting the importance of predation pressure in regulating the population levels of arthropods in forests. Average individual size of predators was approximately proportional to that of prey, irrespective of tree locality. Soil arthropod communities maintained densities approximately 102–103 times as large as the corresponding canopy communities throughout the year. The seasonal variations in abundance were much greater in canopy than in soil communities.
Survival and growth of konara oak (Quercus serrata Thunb.) seedlings in an abandoned coppice forest
Authors: Matsuda Kozue 
Published: March 2006

AbstractSurvival and growth of konara oak (Quercus serrata) seedlings were examined on the forest floor of a konara oak coppice stand in Mitaka, Tokyo, for 5 yr (1976–1980) after exclusion of human management. Attention was mainly focused on a large cohort derived from a bumper acorn crop in 1975. Seedlings began to branch in the second year, although some did not branch during the whole 5‐yr period. Branched seedling showed higher survival and greater weight in 1980 than unbranched seedlings. Many of the branched seedlings had lost an orthotropic leader shoot and spread their branches laterally, suggesting a response for efficient light‐capture. As for unbranched seedlings, a size relationship between leaf area and stem length developing every year was dependent on the shoot size. A small shoot gave priority to enlargement of leaf area, whereas a large shoot gave priority to stem elongation. Yearly variations in seedling mortality and stem elongation were related to the amount of precipitation. Both the initial height and leaf area of germinated seedlings were positively correlated with their survival and weight after five years. Five‐year survival of seedlings showed a positive correlation with light intensity at the growth site but a negative correlation with the extent of leaf predation. Sprouts of shrub species grew vigorously and became much taller than the oak seedlings in the 5‐yr observation period. The characteristics of forest‐floor seedlings were discussed in relation to the regeneration of konara oak forests in general.
Spatial heterogeneity of photosynthetic photon flux density in the canopy of Miscanthus sinensis
Authors: Tang Yan‐Hong , Washitani Izumi , Tsuchiya Takayoshi , Iwaki Hideo 
Published: March 2006

AbstractSpatial variation in photosynthetic photon flux density (PPFD) was investigated in detail at different heights within the canopy of a Miscanthus sinensis grassland to evaluate the light environment of microsites for establishment of heliophilic tree seedlings. Highly heterogeneous patterns of light distribution were revealed within the apparently uniform grass canopies, especially under direct light. The frequency distribution patterns of relative PPFD (RPFD) were compared among different solar and sky conditions. With increasing height in the canopy, the mean RPFD value and standard deviation (SD) increased, while the skewness and kurtosis of the distribution decreased. The mean RPFD and SD were higher, especially at higher solar elevation angles, under direct light than those under diffuse light conditions. The frequency distribution of RPFD was more platykurtic under direct light and at higher solar elevation angles.
Climate and vegetation in China III water balance and distribution of vegetation
Authors: Fang Jing‐yun , Yoda Kyoji 
Published: March 2006

AbstractDistributions of 29 vegetation types in China as a function of climatic humidity or aridity were analysed using Thornthwaite's system, by employing meteorological records from 671 stations in China. The annual potential evapotranspiration and the humidity/aridity indices were calculated for every station, and distribution maps of water deficiency, water surplus and moisture index (Im) were constructed. The Im map showed that arid areas (Im<0) occupied about 56% of the country. The effect of the difference in soil water storage capacity on Thornthwaite's indices was examined, and Im values were found to differ little, although some differences were observed in actual annual evapotranspiration, water deficiency and water surplus values. Correlations between Im values and distributions of 29 vegetation types, identified from a vegetation map with a scale of 1/4000000, were investigated. The distributions of desert, steppe, woodland, deciduous forest and evergreen forest corresponded to Im values of below −40, −40–−20, −20‐0, 0–60 and over 60, respectively. In addition, climatic factors delimiting the northern distribution of evergreen broadleaf forest were investigated, and it was clarified that the northern limit was restricted by combined hydrothermal conditions, and not by the low temperature in winter.
Male reproductive polymorphism and form‐specific habitat utilization of the damselfly Mnais pruinosa (Zygoptera: Calopterygidae)
Authors: Nomakuchi Shintaro 
Published: March 2006

AbstractHabitat utilization patterns were studied in damselfly males, Mnais pruinosa, which have two male forms with different reproductive behaviors. The ‘esakii’ (orange‐winged males) were territorial around oviposition sites, while the ‘strigata’ (hyaline‐winged males) were non‐territorial, often sneaking into the esakii's territory or loitering on the foliage of vegetation along stream banks. The place in the stream in the study area where females frequently appeared was covered by reeds and had abundant oviposition sites. It was difficult for the territorial esakii to stay there because the crowded reeds prevented them from defending their territory and discovering the females. Furthermore, there was competition for the limited territorial space with another species, Mnais nawai. Strigata males concentrated in this place in direct proportion to the number of females. Females frequently mated with strigata males and probably deposited eggs fertilized by strigata sperm rather than esakii sperm. The density of strigata was higher than that of esakii in this study area. If the average reproductive success of esakii and strigata males is equal, this may indicate that the equilibrious point between the two male forms is biased toward strigata.
Ecological geography of the range of the Abies mariesii forest in northeast Honshu, Japan, with special reference to the physiographic conditions
Authors: Sugita Hisashi 
Published: March 2006

AbstractIn the subalpine areas of the snowy regions of Japan (the Japan Sea side), there are some mountains with no or very small stands of Abies mariesii, although this species dominates the subalpine coniferous forests of the region. In order to discuss the cause and process of this phenomenon, present horizontal and vertical ranges, as well as physiographic conditions, of the A. mariesii forest were examined in detail on the mountains in the Tohoku District. Sites in the subalpine zone were classified into two types: ‘azonal sites’ which should be excluded from the habitat of A. mariesii because of their edaphic or small‐scale climatic properties, and ‘zonal sites’. Mountains with vast less‐inclined zonal sites generally had well developed stands of A. mariesii forest. On the mountains with only small, solitary stands of A. mariesii, the distribution was limited to flats or slightly inclined slopes at relatively low altitudes. These less‐inclined zonal sites were regarded as an important habitat for the A. mariesii forest in the Hypsithermal period and the extent of these sites controls the extent of the stands in that period and the success of the subsequent range expansion of the forest.
Ontogenetic changes in stomatal size and conductance of sunflowers
Authors: Furukawa Akio 
Published: March 2006

AbstractThe ontogenetic changes in stomatal size, frequency and conductance (gs) on abaxial and adaxial leaf surfaces of sunflower plants (Helianthus annuus L. Russian Mammoth) were examined under controlled environmental conditions. The stomatal frequency on the adaxial and abaxial leaf surfaces decreased with leaf ontogeny and insertion level. The ratio of adaxial to abaxial stomatal frequency did not change with leaf ontogeny and insertion level, and 42–44% of total stomata was apportioned to the adaxial surface. Ontogenetic changes in stomatal pore length were detected and increased with ontogenesis. The stomatal length of both leaf surfaces had linear relationships with leaf area. Ontogenetic changes in gs were similar between the two surfaces. However the adaxial gs was lower than abaxial gs in leaves of higher insertion levels. Conductance had a linear relationship with width x frequency but not with pore area.
Intra‐ and interspecific variation in body size of Protohermes (Megaloptera: Corydalidae)
Authors: Hayashi Fumio 
Published: March 2006

AbstractThe life history of three populations of Protohermes grandis and two populations of Protohermes immaculatus (Megaloptera: Corydalidae) was compared. In general, the larvae lived in stream riffles for 2 years and the adults appeared in summer. Adult body size differed between these closely related species and also between the populations of P. grandis. Dwarfism occurred in P. immaculatus, a species that is endemic to the small, isolated island, Amami Island. The population of P. grandis on Yaku Island, located between Amami Island and the mainland Kyushu, had an intermediate body size between that of P. immaculatus and the mainland population of P. grandis. Despite being an insular population, P. grandis on Tsushima Island had a similar body size to mainland P. grandis. In these populations with large adults, some larvae lived in the streams for 3 years. The size distribution of benthic animals, which are the prey available to Protohermes larvae, differed between the streams studied. The density of large prey was lowest on Amami Island, intermediate on Yaku Island, and highest on the mainland and Tsushima Island. Different size distributions of available prey may be caused by the differences of benthic fauna; most of Ecdyonuridae and Ephemerellidae (large mayflies) and Perlidae (large stoneflies) were not found on Amami and Yaku Islands. Thus, there is a tendency to dwarfism in the populations of Protobermes inhabiting streams where the density of large prey is low.
Photosynthetic activity and water relations of sprouts of Pasania edulis
Authors: Ito Satoshi , Gyokusen Koichiro 
Published: March 2006

AbstractIn order to investigate the factors causing fast growth of sprouts of Pasania edulis, photosynthetic activity and water relation characteristics of lower (mature) leaves and upper (expanding) leaves of the sprouts were compared with those of seedlings and adult trees of P. edulis. Apparent quantum yield was generally low. Maximum photosynthetic rate was highest in the lower leaves of sprouts. Stomatal frequency was higher in sprout leaves than in seedling leaves. Osmotic potential at the water saturation point and water potential at the turgor loss point, in leaves, were higher in sprouts than in seedlings and adult trees. Symplasmic water content per unit leaf area was higher in sprouts than in seedlings. These water relation parameters in leaves indicated that sprout leaves are superior in maintaining cell turgor against water loss, but are not tolerant to water stress. In field measurements, sprout leaves showed higher stomatal conductance and transpiration rates. These results indicated that sprout leaves fully realized their high potential productivity even under field conditions. The leaf specific conductance, from the soil to the leaf, was higher in sprouts than in seedlings. Large and deep root systems of the original stumps of the sprouts may be attributed to the high leaf specific conductance.
Water intake by the adult mayfly Epeorus ikanosis (Ephemeroptera: Heptageniidae) and its effect on their longevity
Authors: Takemon Yasuhiro 
Published: March 2006

AbstractWater drinking habits during flight in adult mayflies of Epeorus ikanonis Takahashi were observed and the effect of water intake on their longevity was examined. The study was carried out in a mountain stream in western Japan. Adult males collected a water droplet under the head capsule while alighting on the water surface and consumed it after moving to nearby riparian vegetation. The amount of water intake was experimentally estimated to be 9.7% of the bodyweight for males. Although females did not show the water drinking behavior in the field, they imbibed as much as 5.5% of the bodyweight of water in an experimental situation. Morphological observation of the mouthparts revealed that the water was drawn in through the pits at the base of the labrum. In the field caging experiment, males with a water supply had a substantially longer life span than those without. Increase in adult life span by drinking water was less marked in females. Multiple copulation was observed in both sexes during the experiment. The water drinking behavior of the males may closely relate to mating success through increased longevity. Variation in the longevity of adult mayflies was discussed with regard to the possibility of water intake.