MATSUDA, Kozue (Dept. Biol., Fac. Sci., Tokyo Metropolitan Univ., Tokyo). 1985. Studies on the early phase of the regeneration of a Konara oak (Quercus serrata Thunb.) secondary forest. II. The establishment of current-year seedlings on the forest floor. Jap. J. Ecol., 35 : 145-152. Acorn dispersal, germination and the establishment of current-year seedlings of Quercus serrata Thunb. were studied in a newly abandoned coppice of Q. serrata in Mitaka, Tokyo. Acorns were dispersed during the period from the end of September to the beginning of November. Acorns dispersed before the end of October immediately germinated and rooted before winter, though they did not develop shoots until the following spring. A portion of the acorns dispersed later wintered with unsteady or ungerminated conditions and became rooted in the following spring. The foraging activity of voles was not apparent in the present site, except in a poor crop year. A large portion of autumngerminated acorns was killed by weevils and moth larvae invading into cotyledons, or by some agents which ate the tip of radicles soon after germination. Ungerminated acorns were damaged by fungi during winter and by moth larvae and bark beetles in spring. As a whole, 20% of the mature acorns dispersed in 1975 survived by the end of the first growing season.
TANAKA, Nobuyuki (For. & For. Prod. Res. Inst., Ibaraki). 1985. Patchy structure of a temperate mixed forest and topography in the Chichibu Mountains, Japan. Jap. J. Ecol., 35 : 153-167. The structure and floristic composition of a primeval temperate mixed forest on an accidented slope in the Chichibu Mountains was studied from the viewpoint of vegetation dynamics. This forest consisted of patches which were identified by association analysis using the structural as well as floristic attributes. Seven patches showing various structures and floristic compositions developed in the study plot. The Pterostyrax and Fraxinus patches were in the lower parts of the valley, the Betula and two Tsuga patches on the ridges, the Fagus patch in the upper part of the valley, and the Abies patch on the slope between the lower part of the valley and the ridge. The patches were classified into pioneer, building and mature phases according to differences in their tree size, stem density and total stem volume. The Pterostyrax and Betula patches were regarded as pioneer, the Abies patch as building, and the Fraxinus, Fagus and Tsuga patches as mature. The results suggested that after formation of a large gap in an accidented area, several seres would occur and various patches would arise by different processes of species invasion and competition in response to the topography.
YAMAKURA, Takuo (Dept. Biol., Fac. Sci., Osaka City Univ., Osaka). 1985. Statistical basis for the 3/2 power law system (Frequency distribution of individual weight, stem diameter and height in plant stands. VIII). Jap. J. Ecol., 35 : 169-182. When the 3/2 power law of self-thinning holds in forest stands, some interesting relations are recognizable among basal area, mean stem diameter, mean tree height, and tree density in the stands. The relations of these variables, the 3/2 power law of self-thinning, and their derivatives were lumped together in a system designated as the 3/2 power law system. Adopting the results of the preceding last study, statistical models were proposed to explain the interrelationships of the component laws of the system. The fundamental construction of the models depended on Pearson's type VII distribution and upon allometric relations among stem diameter, tree height, and individual weight. To determine the form of each component law of the system, all the coefficients of Pearson's type VII distribution and allometric relations were expressed in empirical equations of tree density in a stand. Although the hypothesis of geometrical similarity in tree shape has been adopted for explaining the construction of the 3/2 power law system, the proposed new explanations for the system were free from the hypothesis.
YABE Kazuo (Env. Conserv., Grad. School Env. Sci., Hokkaido Univ. Sapporo). 1985. Distribution and formation of tussocks in Mobara-Yatsumi marsh. Jap. J. Ecol., 35 : 183-191. Two types of grasslands in Mobara-Yatsumi marsh were studied. The relatively oxidized sandy loam was covered with Imperata cylindrica var. koenigii and Isachne globosa, which could extend rapidly by long rhizomes or stolons and survive under intensive competition in optimum environments. On the other hand, the anaerobic compact muck area was occupied dominantly by Ischaemum aristatum var. glaucum and occasionally by Phragmites communis and Carex thunbergii. Although the latter two could not inhabit the zones where the soil was too anaerobic and the upper muck layer was too thin, Ischaemum could occupy most parts of the compact muck area by making raised tussocks which actively oxidized the anaerobic soil and provided an extra-substratum necessary for their shoots to stand in the thin upper muck layer. Lateral rootlets of Ischaemum grew upward, and new buds were produced in the rootlet ball every year. Repeating this process, the tussocks of Ischaemum seemed to be raised well in several years.
BHARDWAJ, N. (Dept. Bot., Univ. Rajasthan, Jaipur, India) 1985. Effect of Temperature and Photoperiod on growth and reproduction of Tephrosia species. Jap. J. Ecol., 35 : 193-197. The paper describes the results of a field and an experimental study of the effects of temperature and photoperiod on the growth and flowering of Tephrosia apollinea and T. hamiltonii which are common perennial weeds in the semiarid areas of Rajasthan. The plants remain leafless and dry during the winters. The old shoot sprouts during March when the atmospheric temperature starts rising. The plants flower throughout the summer and rainy season. The experimental studies show that the two species are, quantitative intermediate plants (Plants flower under all day lengths but flower best when the day is neither too short nor too long). These growth and flowering is largely governed by the temperature factors, and atmospheric temperature above 30℃ during the day being essential for the bud sprout, leaf growth and flowering.
IHIRA, Masashi (Dept. Biol., Fac. Sci., Kobe Univ., Kobe), MAEDA, Yasuo (Kobe City Inst. Educ. Res., Kobe), MATSUMOTO, Eiji (Marine Geol. Dept., Geol. Survey Japan, Ibaraki) and KUMANO, Shigeru (Dept. Biol., Fac. Sci., Kobe Univ., Kobe). 1985. Holocene sedimentary history of some coastal plains in Hokkaido, Japan. 2. Diatom assemblages of the sediments from Kushiro Moor. Jap. J. Ecol. 35 : 199-205. Diatom assemblages of the sediments from the peat bog along the Toya River, which flows through the east edge of Kushiro Moor, were analyzed to clarify the change in sedimentary environments caused by Holocene sea level changes. The results were as follows : (1) There was the neritic or littoral region of paleo-Kushiro Bay. (2) In the upper part of Md zone, this site changed into a sandy shore. (3) In the Tr-2 zone, this site rapidly changed into a freshwater condition. (4) That change finished bofore 4,090±240 y.B.P. (5) Then, this site developed into a peat bog and streams began to flow in the subzone FD-2 in this site.
TSUTSUMI, Toshio, NISHITANI, Yoshimitsu & SAKAI, Masaharu (Dept. For., Fac. Agri., Kyoto Univ., Kyoto). 1985. On the effects of soil fertility on the rate of soil respiration in a forest. Jap. J. Ecol., 35 : 207-214. The effects of soil fertility on the rate of soil respiration was studied in three Chamaecyparis obtusa stands differing in soil conditions on Mt. Hiei, Shiga Prefecture. The rate of soil respiration increased exponentially with the increase of temperature. The estimated value of Q_10 was about 2 for three stands. The annual rates of soil respiration ranged from 4.54 to 6.40 (C・t・ha^<-1>・yr^<-1>) for three plots studied which were small compared with the rates reported in southern Japan. P-1 was located on lower-slope, where the soil is classified into B_D and the fertility is higher than the soil (type B_B) of P-4 located on upper-slope. The accumulated amount of carbon and the rate of litterfall were high in P-1 and low in P-4. However, the rate of soil respiration was higher in P-4 than in P-1. The soil samples collected from P-1 and P-4 were incubated in 27℃ incubator. The rate of CO_2 evolution was higher for soils of P-4 than of P-1. These results indicate the rate of soil respiration changes depending on the soil type or soil fertility.
SAWADA, Shinichi (Dept. Biol., Fac. Sci., Hirosaki Univ., Hirosaki, Aomori). 1985. Fundamental studies on dynamics of ethylene in ecosystem. I. Atmospheric ethylene concentrations in a Fagus crenata forest and above paddy fields during burning of agricultural wastes. Jap. J. Ecol., 35 : 215-223. Atmospheric ethylene (C_2H_4) levels were examined in a Fagus crenata forest and above paddy fields during the burning of agricultural wastes in Aomori Prefecture during 1980 and 1981. The C_2H_4 concentrations in the forest showed scarcely diurnal as well as vertical variations during the determination periods in August and September. The average concentrations during 24 hr periods were 1.6 ppb in August and 2.2 ppb in September. In July, at the daytime determinations, the C_2H_4 concentrations in the forest canopy were lower than those below the canopy, whereas, at the nighttime determinations, the vertical changes showed roughly the reverse of those observed at the daytime determinations. The C_2H_4 levels during the 24 hr periods fluctuated in a range of 3.3 to 11.0 ppb. At a height of 1.2 m above the paddy fields during the burning of wastes, the atmospheric C_2H_4 concentration was the highest, a mean value of 77.3 ppb, whereas the concentrations decreased with the increase in height and attained a constant level in the range of 1.1 to 1.2 ppb at heights over 1,200 m above the ground surface. The general C_2H_4 levels in the temperate forest ecosystem and in the boundary layer over the main island of Japan (Honshu), in addition to the effects of the levels observed in the ecosystem on physiological processes in plants, were discussed using the present results and other previous data.
SUZUKI, Nobuhiko (Dept. Biol., Fac. Sci., Kyushu Univ., Fukuoka). 1985. Resource utilization of three chrysomelid beetles feeding on Rumex plants with diverse vegetational background. Jap. J. Ecol., 35 : 225-234. Resource utilization and patch use of three chrysomelid beetles, Gastrophysa atrocyanea, Galerucella vittaticollis and Mantura clavareaui, feeding on Rumex plants, were investigated in a habitat with a diverse vegetational background. Mantura, having the shortest food demand among the three species, preoccupied the food resource by the earliest appearance after overwintering, and utilized all food patches regardless of size. The feeding specialist, Gastrophysa, having the largest food demand among the three species, occurred in relatively large patches. Gastrophysa adults appeared even in the patches with a relatively low level of resource abundance in the early stage of the reproductive period, but thereafter gradually became concentrated in the large patches (resource concentration). On the other hand, the feeding generalist, Galerucella, showed no concentration in large patches. In many cases, the resource was preoccupied by Gastrophysa and Mantura because of the latest appearance of Galerucella. However, Galerucella adults lived long and deposited eggs in many patches, resulting in the condition of "spreading of risk" for food shortage. Movement among patches was frequently found, with Galerucella utilizing the patches one after another (opportunistic resource utilization). It was concluded that the difference in resource utilization patterns resulting from different ecological properties and requirements among the three species enabled them to coexist in the same habitat.
TODA, Masanori J. (Inst. Low Temp. Sci., Hokkaido Univ., Sapporo). 1985. Effects of the 1977 eruption of Mt. Usu on drosophilid flies. I. August, 1978. Jap. J. Ecol., 35 : 235-241. Drosophilid vertical distribution from the ground to the canopy in a forest was compared among three places where the forest vegetation was damaged to different degrees by volcanic ash-fall. Interspecific vertical habitat segregation became more obscure in the forest which was damaged more intensively. The living space of drosophilid flies in and near the crater-basin area, where the forest canopy layer was heavily or absolutely damaged, was compressed almost into the layer of floor vegetation. In spite of the absolute damage of forest vegetation, a number of silvicolous species, both canopy and floor dwellers, persisted in the crater-basin area one year after the eruption, and some of them increased their populations, probably due to the abundant food conditions provided by damaged plants.
SAIGUSA, M. (Coll. Liberal Arts & Sciences, Okayama Univ., Okayama) 1985. Tidal timing of larval release activity in non-tidal environment. Jap. J Ecol., 35 : 243-251. The larval release rhythm of the terrestrial crab, Sesarma haematocheir, shows a different strength in the tidal component between Izu (Shizuoka Prefecture) and Kasaoka (Okayama Prefecture) populations. To determine whether this difference is under the direct influence of tides or based on the pattern specific to each local population, comparative studies of the larval release patterns of a certain population under different tidal influences should be available. Field observations were thus carried out at a tributary in the Izu peninsula where the water level was completely uninfluenced by tides. Comparison of the data with those of previous studies made at other sites in the Izu peninsula indicated that the Izu population exhibited the same larval release pattern in these sites. This suggests that the different strengths of tidal component between the Izu and Kasaoka population patterns are specific to each population. Accordingly, tide-correlated factors contributing to the different strengths of that component in both populations are discussed. This paper discusses two possible explanations for the tidal zeitgeber which controls the expression of the tidal component.
KOIZUMI, Takeei and TAMURA, Mitsuho (Dept. Geogr., Tokyo Gakugei Univ., Tokyo). 1985. Periglacial processes and alpine plant communities on the high mountains in Japan, in relation to lithology. VI. Wind-exposed vegetation of Mt. Akaishi, the Southern Japan Alps. Jap. J. Ecol. 35 : 253-262. The windward slope of the alpine zone of Mt. Akaishi is characterized by the dominance of a windexposed herbaceous plant community. However, the percentage of vegetation cover differs from place to place. To clarify the cause of this difference, habitat conditions, especially lithology, coarseness and stability of slopes and soils were examined.
OKUNO, Ryonosuke (Dept. Biol., Fac. Sci., Kanazawa Univ., Ishikawa). 1985. Studies on the natural history of the Japanese toad, Bufo japonicus japonicus. VI. Movements of the young toad. Jap. J. Ecol., 35 : 263-271. Movements of the young Japanese toad, Bufo japonicus japonicus, were studied by the marking and recapture method. During the spring season of age 1,the mean distance between the point of capture and recapture was 44.2m (9-140m) ; during the autumn of age 1.5 years the mean distance was 29.6m (6-75m) ; and during the spring of age 2 the mean distance was 32.7m (7-82m). Mean movement during ages 1 and 2 was 51.4m (3-140m), and 12.8% of the toads were observed to move over 100m. Young toads moved generally from the neighborhood of the breeding pond to the peripheral zone of distribution area, and established their parmanent residences at 2.5 or 3 years of age.