A “Tame-ike” is a man-made irrigation-water pond for agricultural activities, and societies have recognized plural values of irrigation ponds as “commons” or to “secondary nature” to provide cultural and natural resources to regional communities. In this study, we conducted a questionnaire survey in Akashi, Hyogo Prefecture, Japan, to examine differences in the valuations of irrigation ponds between farmers and non-farmers. We defined ‘agricultural value’ as the view that such ponds should be made available for agriculture, and ‘environmental value’ as the view that they should be used for conservation, education, and recreation. Using a social-psychological model, we also investigated how any differences would affect the behavioral intentions of the two groups in terms of conservation of the ponds. Our analyses revealed that non-farmers who participated in conservation activities valued irrigation ponds significantly more than those who did not participate in such activities. Covariance structure analyses indicated that both farmers and non-farmers recognized the multi-layered value of irrigation ponds (i.e., both agricultural and environmental values); however, the farmers’ behavioral intentions towards pond conservation were derived more from their agricultural value, while the non-farmers’ intentions were more dependent on their environmental value.

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To clarify the effects of autumn plowing on the foraging energy efficiency of the Crested Ibis, Nipponia nippon, we determined the biodiversity and biomass in paddy fields, observed the ibis foraging behavior, and conducted a plowing manipulation experiment. From observations, the ibis foraging energy efficiency was calculated 20, 40, and 120 days after autumn plowing, and the ibis prey biomass and physical characteristics of the paddy fields used by the ibis were evaluated at the same times. Using this information, a statistical model explaining the ibis foraging energy efficiency was built using a generalized linear mixed model (GLMM). Path analysis was used to examine the cascade effect of autumn plowing on ibis foraging energy efficiency. In the plowing manipulation experiment, we set up three paddy treatments: no treatment as a control, rotary plow treatment, and subsoiler digger plow treatment. We then investigated the biomass, number of species, and ibis foraging energy efficiency before and after autumn plowing with each treatment. The GLMM showed that the ibis foraging energy efficiency was not determined by the prey biomass, but by the physical environment of the paddy field. Furthermore, path analysis revealed that autumn plowing increased the foraging energy efficiency until 20 days after plowing, while its positive effects were reduced drastically 40 and 120 days after plowing. In the plowing manipulation experiment, there was no significant difference in the number of species before and after plowing with any treatment. Both the rotary and subsoiler digger plows decreased the biomass in the paddy field, while increasing it in the paddy ridge. The GLMM indicated that the ibis foraging energy efficiency from before to after plowing decreased 0.6 times with no treatment, while it increased 1.7 times with the rotary plow treatment and 3.9 times with the subsoiler digger plow treatment. Our results suggest that autumn plowing temporarily increased the ibis foraging energy efficiency, but its effect did not persist for more than 40 days. Use of a subsoiler digger plow would be an effective tactic for increasing the ibis foraging efficiency without having a negative impact on paddy organisms.

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Containment is a realistic goal in invasive species management. In this study, we developed a protocol for establishing a containment plan for an alien snail, Helix aspersa (Cornu aspersum), using government occurrence records, i.e., presence/absence. To establish a containment plan, we need to predict occurrences strictly because the containment plan would not be effective if there were mistakes. We used occurrence records for the target species for 4 years and selected areas where the species was absent for 4 years as absence records to report the presence/absence record accurately. We established a statistical model to explain the conditions in the current distribution range, and then we predicted the probability of presence in neighboring regions, including the current distribution range. We also constructed a map to support establishing a containment plan. The results showed that there was a low probability of absence in the northern portion of the current distribution range. This type of map enables land managers to establish a practical plan to contain the target species. Our ideas are useful for both establishing a containment plan and the use of monitoring records.

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Many native plant species confined to isolated semi-natural grasslands are threatened by local extinction. We evaluated, therefore, the potential role of soil seed banks in the persistence and recovery of native grassland plant populations. We compared species richness and composition between aboveground vegetation and soil seed banks from both surface and lower layers using a seed germination test in isolated grasslands dominated by Miscanthus sinensis and Pleioblastus chino. Although the aboveground vegetation was dominated by native species, exotic species were much more abundant in the surface seed bank than native species, seeds of which were also few in the lower soil layer. The large difference in community composition between aboveground vegetation and seed banks for both native and exotic species, and the similar species compositions between surface and lower soil seed banks suggest that soil seed banks do not contribute to the persistence and recovery of native grassland plant populations in isolated semi-natural grasslands. Moreover, if seed banks were used as restoration tools, the dominance of exotic species poses an unexpectedly high risk of invasion.

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To determine an appropriate management scheme for Satoyama, we established a “mowed site” and a“control site” in 2010 in the Kanto region of Japan, where 30~40 years have passed since the last coppicing event and Pleioblastus chino dominates the forest floor. In each site, we set four plots, characterized by specific microtopographical features (i.e., valley, north-facing slope, south-facing slope, and ridge) and examined environmental conditions, including the fraction of absorbed photosynthetically active radiation (fAPAR), soil moisture, and soil temperature, and species compositions (species diversity and coverage) on the forest floor during 2013~2014. In the mowed site, fAPAR was significantly lower and the species diversity was significantly higher compared with the control site. However, the number of herbaceous plants was only slightly affected by the density of P. chino and was not affected by differences in fAPAR. In addition, plant coverage was highly dependent on microtopographical features, and was higher in the valley. Our results indicate that the mowing of P. chino in abandoned secondary forests generally increases plant species diversity on the forest floor; however, the effect differs significantly according to microtopographical features and the life history traits of plants.

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We conducted small-scale rearing of the endangered species Itasenpara bitterling (Acheilognathus longipinnis) to elucidate the effects of rearing conditions on growth and survival. We focused on daily frequency of feeding (once or three times), density (5 or 20 individuals), and weather conditions (sunshine or shade). We established three experimental groups of 16 each, which were combinations of these conditions. We determined survival rate and measured standard length and weight monthly throughout the experiment. In addition, we determined sexual maturation status. The results suggest that growth was suitable under abundant sunshine at a low density. On the other hand, deteriorating water quality from leftover feed and high water temperature decreased the survival rate. Fish in all experimental groups sexually matured. Consequently, rearing this species in a small aquarium was possible based on the conditions tested, and could be an effective method for conservation of this species.

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Before being found in Kasama Pond in November 2014, Limnoperna fortunei, the golden mussel, had not been observed anywhere in the Naka River system. Kasama Pond is fed from Lake Kasumigaura, where the species has been reported since 2005. To evaluate the introduction and distribution of L. fortunei in the Naka River system, we investigated the population in Kasama Pond from December 2014 to May 2015. We also surveyed a canal, a pond, and two rivers connected to Kasama Pond. In Kasama Pond, we found L. fortunei along half of the shoreline, and collected most individuals near the inflow from Lake Kasumigaura. Based on size-frequency data and previous reports, the first infestation in Kasama Pond must have occurred no later than 2013. Although we also found L. fortunei in a canal that flows from Kasama Pond, we did not detect it in rivers or another pond (Fudo-yatsu Pond) connected to Kasama Pond. To reduce damage from L. fortunei and slow its spread in the Naka River system, it will be necessary to eradicate the species from waterbodies fed from Lake Kasumigaura.

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The perennial herbaceous plant Amsonia elliptica has been designated an endangered species (near threatened, NT) in Japan due to its recent rapid decline in abundance and decreased habitat patches, but there are no precise locality records and habitat characteristics, which are essential for conservation. We first compiled distribution records for A. elliptica from a variety of sources, such as herbarium specimens, publications, and personal information, and then conducted a field survey to examine the numbers of shoots at each locality and the habitat characteristics. A total of 180 locality records were obtained for 38 prefectures from Hokkaido to Miyazaki Prefecture. Of these, we confirmed extinction in seven prefectures, but could not confirm either presence or absence in seven prefectures. Integrated locality records supplemented with our field survey suggested that habitats affected by periodic flooding and high groundwater levels, such as lakefronts, riverbeds, small valley bottoms, and valley slopes, were suitable habitats, and reduced natural disturbance due to flood-control practices and artificial modification of the original topography caused deterioration of habitat suitable for A. elliptica.

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We investigated tree community structure and species diversity of naturally regenerated forests in 11 plots within four urban green areas in Nagoya, Japan. Although tree layers were always dominated by both deciduous and pine species, 50% of plots had evergreen-dominated sub-tree layers, suggesting a transition toward evergreen-dominated forests. Meitoku-koen showed the highest overall diversity and the greatest richness of both native and alien species. Total diversity was hierarchically and additively partitioned into three components: among green areas (β2), among plots within green areas (β1), and within plots. The observed β2 was significantly larger than the expected one and contributed 46% of total diversity, indicating that differences among green areas are important to overall biodiversity. The observed β1 was also significantly larger than the expected one, and included differences in topography and history of past forest use. To conserve the naturally regenerated forests of this region, it is important to avoid further losses of green areas by an urbanization and land development that can reduce habitat heterogeneity.

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Understanding if and how hikers recognize the effects of sika deer (Cervus nippon) browsing on alpine and subalpine vegetation is fundamental to obtaining public support for implementing alpine environmental conservation practices. A questionnaire survey given to hikers visiting Minami Alps National Park revealed that almost one-third of hikers did not know of, or recognize, the impact of deer grazing. More experienced hikers were likely to know of, and recognize, the impact, and they tended to notice the impact of sika deer while hiking. This survey suggested that environmental education and publicity should target less experienced hikers as part of a general publicity campaign.

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