Fine-scale species richness of alpine fellfield plant communities on a middle-latitude mountain of central Japan: Influences of alpine dwarf pine and substrate properties

I compared the vascular plant species richness of fellfield plant communities in the Northern Japan Alps, investigating fine-scale species-area relationships and comparing the number of species in different areas. I also investigated the relation of rate of species richness increase with area in different communities to substrate properties and cover of alpine dwarf pine Pinus pumila. Fellfield plant communities on fine gravel habitats had lower coverage and fewer species than communities on large gravel habitats. The plant community where P. pumila was distributed patchily had the lowest number of species per m^2 but the fastest rate of species richness increase with area. The plant community where P. pumila had developed continuous canopies was mostly composed of species usually found in the alpine-subalpine and lowland zones, whose seeds are dispersed by birds and mammals. The alpine dwarf pine appeared to exclude from habitats alpine specialists that are distributed only in the alpine life zone above the timberline

Notes on floral traits and gender expression of Dryas octopetala under a simulated environmental change

This study presents empirical data for variations of floral traits and gender expression in Arctic Dryas octopetala L. under a simulated environmental amelioration using an open-top chamber (OTC). The short-term experiment (from 8 August 1997 to 2 August 1998) demonstrated in Ny-Alesund, Svalbard that dry weights of gynoecium, peduncle, and hermaphrodite flowers were significantly heavier, whereas petal and androecium weight were significantly lighter in OTC-manipulated shoots than in controls. As a result, "femaleness" (dry-weight allocation to the female organs) showed a significantly higher value in OTC-manipulated shoots as compared to the controls. Moreover, femaleness was significantly positively correlated with flower weight both in OTC-manipulated and control shoots. Thus, it was experimentally demonstrated that the gender as a reproductive effort of D. octopetala flowers changed from male- to female-biased expression under a less stressful condition

Ecological characterization of some selected vascular species in the Arctic environment of Ny-Alesund, Svalbard, in relation to soil moisture conditions

An attempt has been made to characterize and categorize some selected vascular species in the Ny-Alesund area, Svalbard, in relation to soil moisture conditions. A total of sixty releves were established to describe the floristic structures of plant communities. At each releve site, one soil core sample in a 100ml metal container was collected to determine soil physical properties. Samples were oven-dried for 48 hours at 105℃. Moisture content was measured and soil moisture index was calculated for each releve. Based on the index, sixty releves were divided into five soil moisture classes. Throughout the sixty releves, twenty-five species of vascular plants were recognized. Of them, eleven species were selected for this study. They were Salix polaris, Oxyria digyna, Polygonum viviparum, Cerastium arcticum, C. regelii, Saxifraga caespitosa, S. cernua, S. nivalis, S. oppositifolia, Dryas octopetala, and Cassiope tetragona. These were the species that occurred in more than eleven releves out of the sixty. Their frequencies against the soil moisture classes were counted. Ecological distribution curves were constructed for the species. From the distribution pattern, especially the amplitude and the mode position on the moisture classes, the species were classified into six categories as follows, i. e., euryhygrotopic xerophyte, euryhygrotopic mesophyte, euryhygrotopic hygrophyte, stenohygrotopic xerophyte, stenohygrotopic mesophyte, and stenohygrotopic hygrophyte

Increasing Summer Night Temperatures during a 24-Year Periods in Japan:Implications for Rice Production

Summer night temperatures are increasing across most of the globe. In this study, we attempted to detect variability in recent increasing trends in summer night temperatures in Japan. Hourly night temperatures higher than 25°C and 30°C measured by the Automated Meteorological Data Acquisition System (AMeDAS) of the Japan Meteorological Agency were accumulated for each night during each of six approximately 10 day periods during July and August from 1979 to 2002. These two parameters, called ANT25 and ANT30,were used for our analyses. Although increasing trends in night temperature were conspicuous in large cities such as Tokyo, Osaka, and Nagoya, they were also observed widely throughout Japan, including small cities and rural areas. The highest rates of increase in ANT25 were found in early August from Kanto and Hokuriku districts and to the west along the coast. The effects of night warming on rice production in Japan are discusse

Variations of leaf traits of an alpine shrub Sieversia pentapetala along an altitudinal gradient and under a simulated environmental change

We investigated intraspecific variations of leaf traits such as number of leaves, leaf size, leaf mass per shoot, leaf mass per area (LMA) and leaf nitrogen concentration (leaf N), in a deciduous alpine dwarf shrub Sieversia pentapetala (L.) Greene (Rosaceae), along an altitudinal gradient in the Tateyama Range, Toyama Prefecture, central Japan. We also observed the change in leaf traits under simulated environmental amelioration using an open-top chamber (OTC). Three study sites were established at different altitudes (1900-2800m a. s. l.) and the OTC was installed at the highest elevation site. Snow-free duration and foliage period decreased with altitude. The number of compound leaves per shoot and individual leaf size (compound leaf area) significantly decreased, resulting in reduction of leaf mass per shoot with altitude. LMA decreased, while leaf N increased significantly with altitude. Under simulated environmental amelioration (increased temperature), number of leaves, individual leaf size, and leaf mass per shoot increased significantly. LMA showed significantly higher values and leaf N lower values in the OTC manipulated shoots compared with controls. In other words, leaf mass and LMA decrease and leaf N increases under harsh conditions. These variations and changes in leaf traits seemed to be adaptive responses to severe growth conditions to maintain positive carbon balance

Interannual variations in summer temperature on the summit of Mt. Changbai in northeast China

We analyzed interannual variations in summer temperature recorded at the Tianchi meteorological observatory, located near the summit of Mt. Changbai in northeast China during the period from 1959 to 2001. The monthly means of daily maximum temperatures were analyzed with the linear regression model, and showed a significant increasing trend in June during the period from 1959 to 2001. Monthly means of daily maximum temperatures in July appeared to increase after 1990 and those in September after 1970. Monthly means of daily minimum temperatures in August and September also appeared to increase after 1980. However, the temperature increases were more obvious in maximum temperatures than in minimum temperatures during this period. Overall, the means of maximum daily summer temperatures have significantly increased at a rate of 0.28°C per decade

Noise suppression using optimum filtering of OCs generated by a multiport encoder/decoder

We propose a novel receiver configuration using an extreme narrow band-optical band pass filter (ENB-OBPF) to reduce the multiple access interference (MAI) and beat noises in an optical code division multiplexing (OCDM) transmission. We numerically and experimentally demonstrate an enhancement of the code detectability, that allows us to increase the number of users in a passive optical network (PON) from 4 to 8 without any forward error correction (FEC)

Gender variation of Dryas octopetala along snowmelt and latitudinal gradients in the Subarctic and the High Arctic

We describe variations of floral traits of Dryas octopetala L. along a snowmelt gradient within and among three sites : 1) the Subarctic Latnjajaure in northernmost Sweden, 2) the High Arctic Longyearbyen and 3) Ny-Alesund, Svalbard in Norway, also High Arctic. Dryas octopetala had two types of flowers, hermaphrodite flowers and male flowers, lacking any gynoecium. The frequency of male flowers was higher in late snow-melt habitats (i. e. late flowering populations) both at Latnjajaure and Ny-Alesund. Male flowers were significantly lighter in dry weight than hermaphrodite flowers; the difference was larger in the High Arctic than in the Subarctic, suggesting a higher resource limitation in male flowers in the High Arctic. Flower weight also varied among the three sites, and showed a significant difference along the latitudinal gradient both in hermaphrodite and male flowers. In the hermaphrodite flowers, the gynoecium dry weight differed among the three sites, being significantly heavier at Latnjajaure than at Longyearbyen and Ny-Alesund. As a result, the "femaleness" (gynoecium weight/androecium+gynoecium weight) showed significantly higher values at Latnjajaure than at Longyearbyen and Ny-Alesund. Thus, the floral allocation to female function in D. octopetala decreases with an increase in latitude from the Subarctic to the High Arctic. Gender variation of flowers is a size-dependent phenomenon; a positive correlation between flower size and femaleness was observed within each site

Seasonal Variations in Soil Temperature on the Alpine Tundra Community in Mt. Changbai in Northeast China : Comparison with Mt. Tateyama in Central Japan

We examined the synchronization of soil temperatures on an alpine tundra community between Mt. Changbai in northeastern China, and Mt. Tateyama in central Japan. The soil temperatures were measured at one-hour intervals for a total of 7526 recordings at both study sites, where a glacial relict plant Dryas octopetala var. asiatica was predominant. The hourly mean soil temperatures had high synchronization between the two mountains (r2= 0.87). After comparing soil temperatures by dividing the climate into two seasons, we found that synchronization of temperatures between the two mountains was higher in winter (r2= 0.75) than in summer (r2= 0.44). The Arctic Oscillation index, which is related to atmospheric circulation in the Northern Hemisphere, was significantly correlated with air temperature near each study site in the coldest month. Despite the difference in geographical location, a high similarity of seasonal variations in soil temperature in winter suggests that the thermal condition on the two mountains is controlled by the same air masses from higher latitudes. Keywords: Alpine tundra, Arctic Oscillation, Circumpolar plants, Glacial relict, Temperature innovation activities have a high potential to maintainable growth, this strategy alone is inadequate; entrepreneurship that involves a riskier style of management is required. Third, innovation alone carried out by venture enterprises in Japan can not contribute directly to employment creation. Rather, by combining innovation activities with market-in characteristics, enterprises are more likely to realize a surplus quickly, then achieve maintainable growth, thus indirectly contributing to employment creation