Hiromune Mitsuhashi

Aim Natural disaster risk reduction (DRR) is becoming a more important function of protected area (PAs) for current and future global warming. However, biodiversity conservation and DRR have been handled separately and their interrelationship has not been explicitly addressed. This is mainly because, due of prevailing strategies and criteria for PA placement, a large proportion of PAs are currently located far from human-occupied areas, and habitats in human-occupied areas have been largely ignored as potential sites for conservation despite their high biodiversity. If intensely developed lowland areas with high flooding risk overlap with important sites for biodiversity conservation, it would be reasonable to try to harmonize biodiversity conservation and human development in human-inhabited lowland areas. Here, we examined whether extant PAs can conserve macroinvertebrate and freshwater fish biodiversity and whether human-inhabited lowland flood risk management sites might be suitable to designate as freshwater protected areas (FPAs). Location Across Japan. Methods We examined whether extant PAs can conserve macroinvertebrate and freshwater fish biodiversity and analysed the relationship between candidate sites for new FPAs and flood disaster risk and land use intensity at a national scale across Japan based on distribution data for 131 freshwater fish species and 1395 macroinvertebrate species. Results We found that extant PAs overlapped with approximately 30% of conservation-priority grid cells (1 km(2)) for both taxa. Particularly for red-listed species, only one species of freshwater fish and three species of macroinvertebrate achieved the representation target within extant PAs. Moreover, more than 40% of candidate conservation-priority grid cells were located in flood risk and human-occupied areas for both taxa. Main conclusions Floodplain conservation provides suitable habitat for many freshwater organisms and helps control floodwaters, so establishing new FPAs in areas with high flood risk could be a win-win strategy for conserving freshwater biodiversity and enhancing ecosystem-based DRR (eco-DRR).

Major international herbaria, natural history museums and universities have recently begun to digitise their collections to facilitate studies and improve access to collections. In Japan, more than 10 million herbarium specimens are housed in various universities/museums; however, only 1% of these have been digitised. In this paper, we describe a new method for imaging herbarium specimens that is applicable to local/small herbaria. It is safe, fast, simple and inexpensive, but also satisfies usage guidelines for minimum image quality and can produce digital files suitable for long-term storage and future post production. During an eight-month trial at the Museum of Nature and Human Activities, Hyogo, with three part-time workers using a custom-made copy stand and a mirrorless interchangeable lens camera with a large LED light bank system, we were able to image 73,180 herbarium specimens (571 per day on average), obtaining two RAW and two JPEG files for each specimen.

In Japan, a yatsuda is a poorly drained traditional paddy field surrounded by a hilly forested landscape. Yatsudas are biodiversity hotspots, although urbanization is currently causing fragmentation and isolation of these habitats. The Japanese brown frog (Rana japonica) is a yatsuda indicator species that is on red lists in most prefectures in the Kanto region. The habitats and breeding ecology of this species have been well studied; however, little information about fine-scale (100 m to 5 km) isolation of breeding populations is available. We analysed the genetic structure and diversity of breeding-site populations in the suburban landscape of Chiba, Japan. Four major populations were genetically differentiated, to various extents, and we detected gene flow restriction between breeding sites upstream and downstream of the Sakatsuki River. Small breeding population sizes in suburban landscapes can cause unique genetic compositions, and isolation among populations might maintain such differences. Creating terrestrial vegetation corridors and small puddles beside rivers for use as stepping stones might be effective conservation measures.

兵庫県西部を流れる千種川は清流として知られる一方, しばしば大雨による河川氾濫が発生している. 2016年まで, 災害防止の目的で河川整備工事が行われたが, 工事による河川環境の変化や河川生態系への影響が懸念されている. 本研究では千種川の水循環や人為改変の環境影響評価の研究に必要な基礎データを得ることを目的として, 2015年8月9日に採取された河川水試料83点について, 水の水素・酸素同位体比を分析した．分析の結果は地理情報システム（GIS）により流域地図にマッピングした. 結果として, 千種川流域では, 水素・酸素同位体比ともに上流部で低い値を示し, 主要支流の佐用川や, 千種川下流に流入する支流では高い値を示した. また, 上流～中流では高度効果の影響を受けた降水の寄与がみられており, 千種川流域全体で蒸発の影響が大きいことが推測される.

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.

Stream grazers have a major impact on food web structure and the productivity of stream ecosystems; however, studies on the longitudinal (upstream versus downstream) and temporal changes in their drift dynamics and resulting distributions remain limited. Here, we investigated the longitudinal and temporal distributions and drift propensity of a trichopteran grazer, the caddisfly, <italic>Micrasema quadriloba</italic> , during its life cycle in a Japanese stream. The distribution of larvae significantly shifted downstream during the fifth instar larval stage during late winter; with periphyton abundance (i.e. their food source) showing similar shifts downstream. Therefore, our results show that the drift dispersal the caddisfly occurs in response to decline in available food resources (i.e. food-resource scarcity) and an increase in food requirements by growing individuals. Furthermore, our results show that this observed longitudinal shift in larval distribution varies through their life cycle, because the drift dispersal of fifth instar larvae was greater than that of immature larvae. The correlation between periphyton abundance and drift propensity of fourth instar larvae was not statistically significant, whereas that of fifth instar larvae was significantly negative. In conclusion, we detected an ontogenetic shift in drift propensity, which might explain the longitudinal and temporal distributions of this species.

With rapid declines in global riverine biodiversity, conservation is needed on a nationwide scale. Since 1990, the National Census on River Environments (NCRE) has collected meaningful data on riverine organisms and environments in Japan. However, there are several issues with using the NCRE database for scientific studies. In this study, we summarised issues related to the NCRE database, and used the 3^rd NCRE dataset (2001-2005) to evaluate nationwide trends in species richness and the rarity of fishes (primarily freshwater and diadromous fishes) and taxon richness and the rarity of benthic animals (aquatic insects and shellfishes). First, we summarised data quality (e.g. monitoring sites and season) and data formatting issues (e.g. site name and species name). Second, we mitigated these potential issues as thoroughly as possible and tested the relationships of species (or taxon) richness and rarity with latitude using generalised linear models. We found that species and taxon richness showed different latitudinal distributions between primarily freshwater and diadromous fishes and between aquatic insects and shellfishes. In contrast, rarities showed spatial congruence with species diversity, suggesting that more species and rare species could be conserved in the same regions.

We compared the environmental and biotic characteristics of farm ponds with and without the invasive fish, largemouth bass (Micropterus salmoides), and bluegill (Lepomis macrochirus), with varying degrees of aquatic vegetation cover in western Japan. Redundancy analysis (RDA) revealed that aquatic vegetation cover and pond area were significant environmental variables in explaining the variance in aquatic organisms. Aquatic vegetation cover predominantly affected Odonata and Hemiptera larvae, and the native cyprinid, Hemigrammocypris rasborella, while the pond area mainly affected the two exotic fishes (largemouth bass and bluegill), Viviparidae, Oligocheata, Ephemeroptera, and chironomid larvae. In the RDA biplot for aquatic organisms, the RDA1 axis appeared to separate the exotic fish group (bluegill, largemouth bass, Gammaridae, Oligochaeta, Viviparidae, Ephemeroptera, Trichoptera, and chironomid larvae) from the native fish group (H. rasborella, Oryzias latipes, Rhinogobius sp., Odonata, shrimps, and Hemiptera larvae). The best path model results indicated that the presence of piscivorous largemouth bass had a significantly negative effect on native fish numbers; largemouth bass also had a positive indirect effect on benthic organism numbers. Our data suggest that the depletion of native fishes via top-down effects by exotic largemouth bass may indirectly increase the number of benthic organisms as a result of trophic-cascading effects.

To manage the expansion of bamboo forests efficiently, it is necessary to predict where expansion is likely. However, predicting bamboo distribution using statistical models is challenging due to biased distributions, heterogeneous invasion histories, and strong neighbor effects. Furthermore, clonal and invasive species such as bamboo show a non-linear response to environmental factors. Here, we construct a spatial model to predict locations of high penetration probability after controlling for these problems, using data for bamboo distribution in Toyooka, Hyogo Prefecture, Japan. First, we used MaxEnt to reveal the full range of possible bamboo survival and to control for the effects of clonal growth. Second, we constructed a predictive model of invasion using environmental factors. The first model showed that distance from the source patch strongly affected expansion and that constraints from environmental factors were not significant. The final model explained about 70% of actual expansion. Scenario analyses showed that bamboo expansion is best controlled by removing smaller patches. Based on our results, we discuss issues in bamboo forest management and planning.

Propagule pressure plays an important role in the invasion of alien plants into riparian areas. In this study, we focused on propagule pressure from both neighboring riparian areas and anthropogenic land-use areas because propagules are likely to originate from both sources. We tested the effects of whether neighboring units contained the alien plant species, focusing on the direction of invasion by alien plant species into the focal unit, and how much anthropogenic land was contained within the unit, focusing on both farmland and urbanized areas, on alien plant occurrences in Hyogo Prefecture, Japan. We modeled the occurrence of 10 alien plants using generalized linear models to evaluate species invasions by both propagules from both neighboring units and anthropogenic land within a unit. We also investigated the biological and ecological plant attributes that are likely related to invasion success, such as seed dispersal methods, seed size, and clonality, and tested the relationships between the model results and each species' attributes. Results showed that the occurrence of an affected neighboring unit was positively associated with the occurrence of all 10 alien plants. Note that two alien invasive species were influenced by upstream flow direction, six species by downstream flow direction, and in two species, propagule supply was not distinguished by direction. In short, the dominant direction of dispersal was against the stream current, while dispersal in the downstream direction was less common. Species attributes were associated with these directions of dispersal. In addition, anthropogenic land was positively associated with the occurrence of most alien plants, although this effect was weaker than the neighbor unit effects. These results indicate that alien plants spreading into riparian areas do not always follow the natural flow regime; rather, they spread against the flow regime in some cases. We discuss an ecological explanation for these results and provide perspectives for future river management of alien plants that invade the riparian zone. © 2013 Elsevier B.V.

1. While flooding creates diverse habitats for plants and animals in riparian ecosystems, it presents a nuisance to human settlement. Thus, such areas that are frequently disturbed by flooding are more likely to experience strong artificial control measures. 2. This hypothesis was tested and a method was developed to identify these areas using river maps. The effects of two terrain components that could potentially influence flooding frequency (the number of confluences and the degree of meandering per unit area) on both the distribution of threatened species and the degree of artificial modification were examined at two different scales (grid sizes) using two riparian data sources. 3. The numbers of threatened plant species and artificial constructions increased with the number of confluences and the degree of meandering per unit area. The number of threatened plant species was not correlated with the number of artificial constructions. 4. In addition, the results suggest that confluences and meanderings provide different habitat conditions for threatened plant species. Confluences may provide more frequently disturbed habitats, whereas meanderings may provide relatively stable habitats. 5. Based on these results, through flooding, both confluences and meanderings are important for creating and maintaining the diverse habitats used by threatened species, but these habitats are also currently threatened by artificial controls. We suggest that a per-unit-area confluence density and river length map is a helpful tool for locating local biodiversity hot spots. The identification of major reservoirs of biodiversity that are currently threatened can improve conservation and management planning. Copyright (C) 2011 John Wiley & Sons, Ltd.

Stream classifications and indicators that are capable of summarizing the complex information of ecological communities provide useful tools in river ecosystem management. However, these tools have not yet achieved practical application here in Japan due to the fact that in many studies, the criteria for selecting stream classifications and indicators are neither objective nor quantitative. Combining model-based clustering and indicator values (IndVal) makes it possible to assess the appropriateness of stream classifications based on the indexability from multiple classifications. Additionally, by establishing threshold values, indicators can be objectively selected. Using these techniques, we examined appropriate data acquisition methods for determining a stream classification system for vegetation at the catchment scale. Additionally, we studied the suitability of methods that were derived solely from either biological or environmental data as well as those that combined the two. We prepared three sets of data that utilized different research zone and scope-setting methods and then created three types of stream classifications from each, ultimately evaluating the appropriateness by the quality of selected indicators and the level of indexability. The most appropriate methods involved those derived from biological and environmental data exhibiting consistently high indexability as well as those that created vegetation maps in certain areas of the distribution over the entire catchment area. Furthermore, the quality of the selected indicators was consistent with the indexability results.

Determining ecological indicators and habitat classifications using standardized methods at the catchment scale is crucial to ecosystem-based management. Through investigations of vegetation and environmental factors at 66 sites located in the Ichi River in Hyogo Prefecture, Japan, we classified the types of environments and the corresponding indicator communities at the catchment scale. Data were analyzed using the optimum clustering method, for which the correct number of clusters was determined by model-based clustering and indicator values (IndVal). The indicators of specificity and fidelity in either cluster were reflected in actual site conditions. Results indicated that physiotope may be important for habitat classification at the catchment scale.