Stream classification at catchment scale is important in river ecosystem management; in recent years, it has often been used in conservation planning. Stream classification at catchment scale is often based on biological data obtained at discrete survey locations. Obtaining continuous biological data as vegetation maps on rivers is labor intensive. In this study, we divided the river into many segments of equal length (500 m) and recorded vegetation types that appeared in each segment through fieldwork. Obtained data that recorded the presence and absence of vegetation type for each segments were ordinated into two-dimensional space using a non-metric multidimensional scaling method, and segments were classified through non-hierarchical cluster analysis using the k-means method based on the scores obtained by the non-metric multidimensional scaling. Using index indicators (IndVal), we obtained indicator vegetation types specific to each cluster. We discussed the characteristics of each cluster on the basis of the river topography and composition of vegetation types. Clusters obtained using the present method represent a good classification that reflects characteristics of river segments. The labor effective stream classification at catchment scale become possible by this method and it is a useful tool in river ecosystem management. Our approach should be applied and evaluated in other river systems with various topography, surrounding land uses, and climates regime.

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The range of the invasive redback spider (Latrodectus hasseltii) in Japan has expanded over the past 20 years, since its introduction in Osaka Prefecture, and monitoring and prediction of its occupancy area expansion are required. We predicted occupancy area expansion by this species in Kinki District, Japan, using a migration kernel function integrating random walk migration and anthropogenic transportation. The probability of random walk migration was estimated using the logistic function of annual migration distance, where a random walk distance upper limit of 9 km provided the optimum estimation. We determined the probability of anthropogenic migration according to the geographic attributes of transportation centres (airports, ports, roads, and truck depots) and traffic intensity (for journeys by rail, bus, car, and bicycle). The predicted probability of migration successfully simulated the rate of discovery until 2013. Finally, we used a Monte Carlo simulation to predict redback spider habitat expansion until 2045; our results suggest occupation of its entire potential habitat will occur by 2045.

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The Toyohira River, which flows through the Sapporo metropolitan area, is annually supplemented with ~200,000 fry of the chum salmon Oncorhynchus keta. The river additionally supports a naturally spawning chum salmon population composed of over half of all salmon returning to the river. Recent studies have suggested that hatchery releases may exert negative effects on wild salmon productions. However, it is unclear whether the salmon population of the Toyohira River would persist without hatchery supplementation. We proposed a management procedure for determining the stocking efforts of salmon fry with a feedback control loop to reduce the risk of population decline. The performance of the management procedure was evaluated by simulation using the operating model. The operating model was based on the age-structured Ricker-logistic population model with environmental and demographic stochasticity. Our results showed that implementation of the management procedure with a feedback control loop wherein the number of fry released was adjusted based on the number of returning adults resulted in relatively good performance with a small risk of population decline. Thus, this procedure, implemented in 2016, reduced the number of hatchery fry released in that year to 85,100 (43% of the normal level).

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A reduction in semi-natural grasslands threatens grassland flora and fauna with extinction. The grasslands on mountain summits are considered important habitats for some grassland plant species; however, it is not clear which environmental factors influence the presence of these plants. This study focused on the semi-natural grasslands remaining on eight mountains lying northwest of Hiroshima. We investigated the composition, biodiversity, surface area coverage, and relationships among grassland plant species. Considering the locations of species relative to the summit, the characteristics of the summits could be discerned among large-scale semi-natural grasslands. On summits subject to previous grassland management, a large proportion of the vegetation remained, and even after conventional management had been discontinued. Vegetation diversity was positively correlated with grassland coverage, indicating that the main factor limiting plant species diversity is grassland coverage. These results indicate that many of the plant species growing in grassland areas also grow on summits.

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Following a multi-site survey in Hyogo Prefecture, Japan, we used a generalized linear mixed model (GLMM) to predict the effects of deer overgrazing and overgrowth of lucidophyllous trees on species density of vascular plants in secondary Quercus serrata forests. We found that species density was explained well by both factors. The effects of deer overgrazing and overgrowth of lucidophyllous trees were estimated spatially by substituting raster data for GLMM results in a Geographical Information System (GIS) environment. We found that a decrease in vascular plant species density due to overgrazing of deer occurred mainly in higher-altitude forests (› 300 m), whereas a decrease in species density due to overgrowth of lucidophyllous trees occurred mainly in lower-altitude forests (› 300 m). Thus, using the spatial differences between the two factor effects in the study area, we showed that there has been a change in both the distribution of the local deer population and the spatial variation of climatic conditions over the past several decades.

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Cephalanthera are orchids that grow in secondary forest in Japan. They are mixotrophic species associating with mycorrhizal fungi. Their habitat is decreasing with the expansion of abandoned secondary forests in Japan. Recently, there has been additional concern about the damage to their seeds caused by leaf-miner flies. In this study, we examined (1) relationships between the distribution of three Cephalanthera species (i.e. Cephalanthera falcata, C. erecta, and C. longibracteata) and forest management, (2) methods for improving habitat conditions, and (3) the damage to seeds caused by feeding leaf-miner flies. We also discuss possible conservation measures for Cephalanthera. The study was conducted in a secondary forest (20.5 ha) in southern Ibaraki Prefecture. Cephalanthera habitats were clustered in the forest-management area (47 sites, 881 individuals) and the number of individuals differed depending on the environmental conditions in the forest (i.e. understory vegetation, species and diameter at breast height of neighbouring trees, soil hardness, and canopy openness). Leaf-miner flies caused extensive damage to the seed production of Cephalanthera. We concluded that both forest management and leaf-miner fly control are important for Cephalanthera conservation.

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A floating-leaved plant species, Trapa japonica, that is native to Japan has recently expanded to cover a large area of the water surface of Lake Mikata, Japan. Mapping and monitoring of T. japonica is required for effective management. I used the RGB values of unmanned aerial vehicle (UAV) images for this purpose. I compared images taken at heights between 20 and 50 metres above ground level, and selected a flight height of 20 metres to ensure good image resolution. I then created an orthomosaic of pixel size 0.9 cm from the UAV images. Generalised linear models (GLMs) were constructed to predict T. japonica occurrence from the RGB data of the orthomosaic image. The presence/absence of plants at training points on the image was judged visually. Using a logistic regression model, the green band differentiated T. japonica from open water with the highest accuracy. The overall accuracy and the area under the receiver operating characteristic (ROC) curve (the AUC) were 91.5% and 0.97, respectively, for the validation dataset. These results suggest that UAV images with RGB values are useful for mapping T. japonica rosettes in a lake.

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Wind power generation plants are a worldwide concern because of their potential negative effects on bird populations. To reduce this impact, theoretical models that evaluate the risk of birds colliding with wind turbines have been implemented for wind farms as part of environmental impact assessments. However, collision risk evaluation models have various difficulties when predicting collision events for each wind turbine within a given wind farm due to different topological features and local weather conditions. Current collision risk models require species-specific avoidance rates to estimate collision risk, but there are no data on the avoidance rates of bird species in Japan. Moreover, few impact assessment practices have considered either the long-term impact of each wind power plant on bird population viability or the cumulative impact of multiple wind farms on bird populations, although both considerations are critical requirements for the conservation of endangered species in areas where many wind farms have been built. This paper reviews the data on the collision and avoidance rates of many bird species over various geographic ranges and the long-term and cumulative impacts on bird population viability, with the aim of implementing contrivance measures for the bird collision risks at operating and planned wind farms.

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The estimated minimum standard length (SL) to attain sexual maturity in largemouth bass, Micropterus salmoides, in Japan, is 230 mm. We observed the gonadal development of smaller largemouth bass (two males, 162-169 mm SL; two females, 182-204 mm SL) captured in an artificial pond located at the University of Shiga Prefecture. This study and two previous reports suggest that largemouth bass can mature at smaller sizes than previously reported. Maturity with smaller body size may be related to genetic exchange with other smaller geographic subspecies and environmental factors, such as the amount of food and water temperature.

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A field survey was conducted in irrigation ditches in Kinomoto-cho, Nagahama City, Shiga Prefecture to clarify the distribution and habitat characteristics of unionid mussels. Seven unionid species (Pronodularia japanensis, Pseudodon omiensis, Sinanodonta japonica, Lanceolaria grayana, Inversidens brandtii, Nodularia douglasiae biwae and Inversiunio yanagawensis) were collected from October to November 2015. The relationship between mussel density and physical factors was analysed using generalized linear models (GLMs) for all but one rare species (I. yanagawensis). The GLM results indicated that the densities of P. japanensis and P. omiensis were higher in ditches with a sand bottom, hard sediment and shallow depth; the density of S. japonica was higher in ditches with a sand bottom, hard sediment, shallow depth and slow flow velocity; the density of L. grayana was higher in ditches with a sand bottom and hard sediment, and the density of N. d. biwae was higher in ditches with hard sediment and slow flow velocity. No parameter clearly affected the density of I. brandtii. A range of ditch environments should be maintained or restored to conserve unionid mussels because mussel species are likely to differ in terms of the most suitable environment for habitation.

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The Raiba wetland (approximately 0.9 ha) is a Sphagnum wetland that was discovered in the Kuromatsunai lowlands of Hokkaido, northern Japan, in 2011. We reconstructed the land-use and land-cover history of the wetland (1948-2005) using aerial photo interpretation and information obtained through interviews with local people. Our analysis revealed that the present wetland vegetation has developed through natural colonisation following anthropogenic disturbance, consisting of surface soil removal and road construction for residential development around 1976. In the wetland, we recorded Sphagnum squarrosum and 111 vascular plant species, including 4 threatened species and 8 alien species. The Sphagnum patch was significantly associated with areas of bare soil exposed after soil removal. These results suggest that past removal of surface soil has had a major influence on the present state of the vegetation in this wetland.

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Darwin Core/Darwin Core Archive is a standard data format used for biodiversity information. However, because Darwin Core generally supports presence-only data, it is difficult to adapt to other types of ecological data, such as presence/absence data and monitoring data. In 2015, the Biodiversity Information Standards Taxonomic Databases Working Group, which is responsible for maintaining Darwin Core, released a new type of information to be handled in Darwin Core called “Sample-based Data”, to adapt quantitative information, particularly ecological monitoring and assessment data. Sample-based Data has great potential for facilitating data sharing and integration, which is one of the goals of several biodiversity-related communities, such as The Group on Earth Observations Biodiversity Observation Network. In this article, we describe both Darwin Core and Sample-based Data in detail to facilitate biodiversity data sharing and integration in Japan.

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To evaluate the effectiveness of bat gates for cave-dwelling bat conservation, the relation between cave use by bats and the characteristics of gates of various types, structures, materials and sizes were investigated at 10 caves in Mie Prefecture. The gates were divided into two types: bat grills and half-gates. Bats with low-aspect-ratio (broad and short) (Rhinolophus ferrumequinum, Rhinolophus cornutus, and Murina hilgendorfi) and intermediate-aspect-ratio (Myotis macrodactylus) wings entered caves fitted with either grills or half-gates. However, Miniopterus fuliginosus, which has high-aspect-ratio (narrow and long) wings, used only caves with half-gates. In the distribution area of M. fuliginosus, half-gates should be adopted for conservation of cave-dwelling bats.

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We propose a method for selecting broad-leaved tree species for planting based on an assessment of the survival of broad-leaved trees in a seaside-protection forest after the Great East Japan Earthquake Disaster. We investigated the frequency of seeding, sapling, adult trees, and their seed production of broad-leaved trees in each forest layer (0-0.5, 0.5-2, 2-5, 5-10, and ＞10 m) of a 50 × 50 m² study plot in a seaside-protection forest in Yamamoto, Miyagi Prefecture, approximately 2.5 years after the disaster. Using the obtained data and standards that we determined, we selected 9 broad-leaved tree species (Alnus japonica, Euonymus alatus var. alatus f. striatus, Ilex crenata var. crenata, Ilex serrata, Ligustrum japonicum, Mallotus japonicus, Morus australis, Neolitsea sericea, and Viburnum dilatatum) for planting, in addition to two other tree species (Cerasus jamasakura and Quercus serrata) chosen by the government of Miyagi Prefecture.

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