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In Southeast Asian tropical rainforests, two events, severe droughts associated with the El Niño-Southern Oscillation and general flowering, a type of communitywide mass flowering, occur at irregular, supra-annual intervals. The relationship between these two supra-annual events and patterns of insect population fluctuations has yet to be clearly elucidated. Leaf beetles (Chrysomelidae) are major herbivores and flower-visitors of canopy trees, affecting their growth and reproduction and, in turn, affected by tree phenology; but their population fluctuations in the Southeast Asian tropics have not been extensively investigated. We examined population fluctuation patterns of the 34 most dominant chrysomelid species in relation to the two supra-annual events by conducting monthly light-trapping over seven years in a lowland dipterocarp forest in Borneo. Our results showed large community variation in population fluctuation patterns and a supra-annual (between-year) variation in abundance for most of the dominant chrysomelids that was significantly larger than the annual (within-year) variation. Specifically, in response to a severe drought in 1998, chrysomelid species exhibited different population responses. These results show that population fluctuations of individual species, rather than the entire assemblage, must be analyzed to determine the effects of changes in environmental conditions on the structure of insect assemblages in the tropics, especially in regions where supra-annual environmental changes are relatively more important than seasonal changes. [ABSTRACT FROM AUTHOR]

Fairly high collagenase activity was initially demonstrated in human whole saliva, and the activity from patients with periodontal diseases was statistically higher than that from healthy subjects. Based on some characteristic properties, the collagenase in whole saliva appeared to be of tissue, rather than bacterial, origin. [ABSTRACT FROM AUTHOR]

To clarify the effect of shelterwood logging on the diversity of plant species in a beech (Fagus crenata) forest in central Japan, we compared the species composition and the organization of vascular plant communities in stands that were managed 10 years ago with those in primary stands. There were no significant differences between the stands in the species diversity (H', J', and number of species) of either forest floor plants or tree species. The species diversity of forest floor plants was significantly positively correlated with stand structure parameters (number of stems and number of stems per individual, and frequency of occurrence of dwarf bamboo) that increased in value after logging. However, the number and the frequency of occurrence ofspecies that occurred disproportionately in primary stands were significantly negatively correlated with the same parameters. Shelterwoodlogging has been reported to make effective beech regeneration more difficult in many Japanese beech forests, including this forest, but this method might not significantly affect plant species diversity. [ABSTRACT FROM AUTHOR]

The effects of tree bark-stripping by Sika deer (Cervus nippon) on population dynamics of forest trees were studied in a cool-temperate mixed forest in Ohdaigahara, western Japan. Detailed observation of all trees =/> 2 cm in diameter at breast height in a 1 ha plot for 2 years showed that stems of Abies homolepis, Clethra barvinervis, Viburnum furcatum, Stewarria pseudocamellia and Ilex geniculata suffered serious bark-stripping by deer. Smaller stems of A. homolepis were girdled all at once, and dead soon after that. Larger stems were bark-stripped little by little, and did not die unless completely girdled. Stems of C. barvinervis and S. pseudo-camellia did not die soon after bark-stripping even if completely bark-stripped. The tree population monitored in two 0.2 ha belt transects for 15 years demonstrated that the mortality of A. homolepis and V. furcatum has increased consistently, especially in the last 5 years. In contrast, no tendencies were found for Fagus crenata, Pourthiaea villosa and Symplocos coreana; these species were seldom bark-stripped by deer. Recruitment rate in the whole forest decreased in recent years. Thus the density of smallertrees decreased due to high mortality of bark-stripped species and low recruitment rate for all species. Though the bark of trees is lessimportant as forage for deer than green forage such as dwarf bamboo,bark-stripping does more serious damage to trees than browsing on leaves and twigs because the injury by bark-stripping does not readily recover and kills considerably large trees. The ratio of canopy gap will be increased by browsing unless the density of deer is reduced. Furthermore, bark-stripping accelerates the increase of canopy gap ratio. (c) 1999 Elsevier Science B.V. [ABSTRACT FROM AUTHOR]

Structure, diversity and dynamics of five Japanese temperate old-growth forests were compared, differing from each other in. i.a., climate, dominant tree type, topography, disturbance regime. The forests were Aya, Ogawa, Kanumazawa Riparian, Kanumazawa upland and Senju. A permanent plot (1 - 6 ha) was established in each forest and trees werecensused several times at intervals of two years. Mean annual recruitment rates and mortality rates in these forests were both in the range of 0.5 to 4.6%/yr at the community level. Analyses of the structure and dynamics of populations showed that the underlying process was different among the forests. Some forests experienced compositional shifts in their canopies, others had a constant canopy composition butappeared to lack effective regeneration in recent years. The recruitment rate appeared to be strongly affected by competitive undergrowthvegetation such as dwarf bamboo which has been controlled by naturaldisturbance or human impact. It is likely that the forests with mostly low recruitment rates had a low species diversity. The current variation in structure, diversity and dynamics of the studied forests might have been determined not only by physical conditions (e.g. climate) but also by chance factors (e.g. disturbance, outbreak of deer population). [ABSTRACT FROM AUTHOR]

The decline of wild bee populations causes the decline of bee-pollinated plant populations through the deterioration of pollination services. Since high bee species richness generally involves high functional group diversity, protecting areas of high bee species richness will help to maintain pollination services for plants. However, those areas do not always include the habitats of bee species with specialized functions that expand the range of plants being pollinated. To map important areas for protecting native bee species and their functions, we estimated the distributions and functional range of 13 bumble bee species and 1 honey bee species in Japan. The distributions were estimated from an ensemble of six species distribution models using bee occurrence data and environmental data. The functional range of bee species was estimated by combining the estimated distributions and proboscis length, which frequently corresponds to the floral shape of the plant species they pollinate. The estimated species richness was high in western Hokkaido and the estimated functional range was wide in central Honshu. Our method is useful to see whether areas important for high species richness of pollinators differ from those for rare species or their functions., (© 2024. The Author(s).)

Information provision is essential for obtaining the cooperation of the general public for the conservation of unfamiliar ecosystems towards a sustainable (e.g. carbon-neutral and nature-positive) society. The purpose of this study is to identify effective ways of raising public awareness for ecosystem conservation. We explored the interaction between the manner of information provision (i.e. the medium through which and how much information is provided) and the personal attributes (e.g. environmental attitude) of the recipients on their willingness to pay (WTP) for conservation using Japanese alpine plants as the subject. Discrete choice experiments using an online survey were conducted with public citizens aged 20-69 years across Japan, and data from 8457 respondents were analysed. The data analysis was performed in two steps: 1) estimating individual WTP and 2) exploring factors affecting WTP. The results demonstrated that individual WTP was 135,798 ± 82,840 (mean ± standard deviation) JPY per person for a lifetime. The WTP increased when information was provided in the form of short texts and graphics for those proactive about nature conservation, but increased more when video information was provided to those reactive about nature conservation. The study shows that ecosystem conservation groups need to adapt the amount and format of information for target audiences (e.g. Generation Z youth, who are more sustainability-oriented and prefer to accomplish more in less time)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In this study, we examined roles of three vegetation characteristics in provisioning of a recreation service by applying a machine-learning method to 4,708,229 spatially-explicit records of hiking activity in Japan. Then, expected impacts of land-use changes assessed and mapped based on the model. Associations between a recreation service and three vegetation characteristics were considerably variable depending on the social and natural environment such as accessibility and altitude. As a consequence, expected impacts of unit changes in vegetation characteristics on the service flow were considerably heterogeneous throughout the study area. The signs (positive or negative) of the impact can be reversed depending on the contexts even among nearby sites. Such notable but variable contributions of vegetation on a recreation service should be carefully reflected in landscape management. Even moderate changes in either the quantity or quality of vegetation can have a considerable impact on the frequency of hiking activity. Landscape management for promotion of the recreation service should be carefully designed for each locality on the grounds of the context-dependent effects of vegetation., (© 2023. The Author(s).)