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Macrophytes, comprising aquatic vascular plants, bryophytes, and macroalgae, including charophytes, are crucial components of lake ecosystems. Their diversity affects ecosystem functions and services, and they are sensitive to environmental changes, making them effective indicators of lake health. Historical records of macrophyte species composition are essential for evaluating environmental changes and conservation goals. In this study, we compiled a comprehensive database of macrophytes, along with lake and survey information from the literature, providing a historical record of macrophyte biodiversity for lakes in Japan. This database enables the analysis of changes in the flora of Japanese lakes and fluctuations in species distribution, facilitating future monitoring. The complete dataset for this abstract published in the Data Article section of the journal is available in MetaCat in JaLTER at http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2024-02.1/jalter-en. [ABSTRACT FROM AUTHOR]

Masked palm civets (Paguma larvata) are increasing in abundance in Japan, and understanding their den preferences may help control their numbers. We investigated the den site selection and use patterns of masked palm civets, as well as seasonal changes in selection and use, in urban areas in Japan using radio tracking. We tracked 5 civets in the Daijiji and Kamido areas of Morioka City, Iwate Prefecture and identified 84 den sites that were used a total of 245 times by those civets. Overall, civets chose buildings more frequently than warehouses or the outdoors as den sites. Outdoor den sites were used only in summer. For each individual, about half of the den sites were used only once. On the other hand, the top three den sites with the highest number of uses accounted for 40–60% of the total number of uses. In Daijiji, civets selected significantly more temples/shrines and significantly fewer residential houses than expected; however, across the sites residential houses were used more frequently than any other site type. In winter, civets depended on better insulated buildings (e.g., temples/shrines and residential or vacant houses) and tended to use the same den sites continuously. These results indicate that civets living in urban areas tend to select buildings as den sites. Therefore, not only to reduce property damage, but also to create an environment that makes it difficult for civets to overwinter, it is important to manage buildings, so that civets cannot use them as dens. [ABSTRACT FROM AUTHOR]

Simple Summary: Microsporidia are intracellular parasites that have detrimental effects on their various invertebrate and vertebrate hosts. The microsporidia pathogenic to honeybees and bumblebees belong to the genus Vairimorpha (previously Nosema). Among these, V. bombi is the most widespread species worldwide and it infects a variety of bumblebee species. In this study, we investigated the infection of V. bombi among Japanese native bumblebees and the alien species, Bombus terrestris, established in Japan, using PCR and microscopy. We discovered that V. bombi infected the subgenus Bombus s. str. species/subspecies with a low prevalence in areas both with and without the presence of B. terrestris, suggesting that V. bombi may be native to Japan. In contrast, a newly discovered microsporidian parasite that is phylogenetically distinct from V. bombi was found to infect the subgenus Diversobombus species/subspecies with a high prevalence. Hence, if the new microsporidian species does not negatively affect the host and is vertically transmitted from queen to offspring, it may coexist with its host. In addition, this may suggest that V. bombi and the new microsporidium have different life history strategies. Microsporidia are spore-forming intracellular parasites of various invertebrates and vertebrates. Vairimorpha bombi negatively affects the fitness of bumblebees and its prevalence correlates with declining bumblebee populations. The invasive alien species Bombus terrestris colonized Japan and possibly introduced new parasites. To assess the infection prevalence of V. bombi in Japanese bumblebees and B. terrestris, we investigated V. bombi infections using PCR and microscopy. The prevalence of sporulating V. bombi infections in three Bombus s. str. species/subspecies was low, whereas that of non/low-sporulating Vairimorpha sp. infections in three Diversobombus species/subspecies was high. Invasive B. terrestris showed low prevalence of non/low-sporulating V. bombi infections and shared the same V. bombi haplotype with B. hypocrita found in Hokkaido, where B. terrestris is present, and in Honshu, where B. terrestris is absent. Although V. bombi may have been introduced with B. terrestris colonies imported from Europe, it seems to be originally distributed in Japan. Furthermore, a new Vairimorpha sp. was found in Japanese bumblebee species. V. bombi and Vairimorpha sp. showed different organ and host specificities in bumblebees. There are no reports on the specific effects of other Vairimorpha spp. on bumblebees; further studies are needed to clarify the individual characteristics of Vairimorpha spp. [ABSTRACT FROM AUTHOR]

The various problems caused by invasive species have become more serious in recent years, and thus it is important to discuss their identifications and invasion processes. Phylogenetic and population genetic methods are effective tools for solving these problems. Some land snails, including the genus Macrochlamys, have invaded and established themselves worldwide as invasive species. In this study, we identified the species of Macrochlamys sp. from Japan and estimated their invasion pathways to Japan. Phylogenetic analysis showed that the Japanese snails were closely related to Macrochlamys indica from Bangladesh and West Bengal. Population genetic analysis also revealed that most of the Japanese snails were concentrated in single haplotype and were close in genetic distance. Detailed anatomical investigation of genitalia and oral organs showed morphological similarities between the Japanese and Bangladeshi snails, supporting the results of the phylogenetic analysis. These findings suggest that the Japanese Macrochlamys sp. is recognized as Macrochlamys indica and may have been introduced from the vicinity of Bangladesh and West Bengal and subsequently spread within Japan. [ABSTRACT FROM AUTHOR]

We identified an alien praying mantis found in Japan as the giant Asian mantis Hierodula chinensis by observing the characteristics of male genitalia. Nymphs hatched from oothecae collected in Nara Prefecture, Japan, were reared in a breeding room and compared with nymphs of the native Japanese species H. patellifera. Different from H. patellifera, the H. chinensis individuals passed through 5–7 nymphal instars before emerging as adults. The body color of the H. chinensis nymphs was brownish gray in the first instar, whereas the second and later instars were green. Unlike H. chinensis, H. patellifera had mottled patterns all over its body during the first to third instar. The first to third instar nymphs of H. chinensis had mottled patterns on the femurs of their forelegs, which is a diagnostic characteristic that no native praying mantis species has. From the fourth instar, 7–10 dorsal spines were observed on the foreleg coxa of H. chinensis, whereas only 3 or 4 spines were observed in H. patellifera. These findings show that H. chinensis and H. patellifera can be distinguished in all nymphal instars. [ABSTRACT FROM AUTHOR]

Galba humilis (Say, 1822) is a freshwater mollusc belonging to the family Lymnaeidae, and it is distributed in North America. The present article documented the first record of this mollusc in Japan, which is outside the indigenous distribution range of the species. The species was identified using molecular phylogenetics. This is the first report of G. humilis introduction in the world, including Japan. [ABSTRACT FROM AUTHOR]

Despite its potential use for population control, the winter ecology of nonnative fishes is still poorly understood due to the difficulty of conducting field surveys. In this study, we investigated the winter habitat use of invasive rainbow trout Oncorhynchus mykiss at the cannel unit scale (i.e., pool, riffle). Twenty-four reaches were surveyed in late December 2013 along the Obicha River, a tributary of the Otofuke River, Tokachi River basin, Hokkaido, Japan. A total of 532 fish were captured, of which 96% were rainbow trout, whereas native salmonid was only a single southern Asian Dolly Varden Salvelinus curilus. Smaller rainbow trout (< 250 mm) used reaches with low velocity, whereas larger trout (250–520 mm) aggregated in specific reaches with deep pools with abundant cover and coarse substrate. A previous tributary-scale study in the same river system showed the importance of velocity and temperature, but not depth and substrate. Therefore, habitat selection would be scale-, as well as size-, dependent. This study provides useful information on capturing large mature adults in winter for effective control of nonnative salmonids. [ABSTRACT FROM AUTHOR]

Thanatus vulgaris Simon 1870 is newly recorded from Japan. This species was known as a species distributed in Europe, the Far East, Central and East Asia, North America, South Africa and Australia. In East Asia, it was recorded from China and Korea. In Japan, it was collected at a livestock farm and is considered to be anthropogenically distributed, having been brought in with imported feed. [ABSTRACT FROM AUTHOR]

Resilience theory has increasingly been adapted to the literature associated with nature-based tourism, including wildlife tourism.　The present study draws on a case of free-ranging rabbits inhabiting Ōkunoshima Island in Hiroshima, Japan.　In particular, the study discusses how an alien species became a popular tourist attraction and challenged the existing and widely accepted conservation-based wildlife tourism management by incorporating resilience thinking in the context of social change.　Ōkunoshima Island has transformed drastically over the last 70 years.　During World War II, it was a military base for producing poisonous gases.　In 1960, the island was designated as the National Vacation Village to promote tourism; for decades, it was a recreational and educational site for visitors to learn about the island's wartime history.　A major shift in the island's tourism industry occurred in 2015 when its exposure to social media resulted in a growing number of domestic and international tourists.　Since then, the island's rabbits have become its primary tourism resource and attraction, attracting not only the largest number of tourists ever but also a fair share of challenges.　In addition to the internationalization of tourist profiles, the types of tourists that visit the island has been altered.　The growing popularity of rabbit tourism has over-crowded the island.　Furthermore, tourists want to feed the rabbits, resulting in the rabbits' dependence on human food handouts and overpopulation.　Problems associated with the proliferation of rabbits require the destination's managers to intervene.　However, the rabbits' status as an alien species has complicated the decision-making process.　In favor of being adaptive to social change, this study argues that the destination management policy needs to rethink the concept of alien species and to look beyond the conventional conservation approach. [ABSTRACT FROM AUTHOR]

This is the first large dataset of underwater videos from which species occurrence and behavioral records of aquatic organisms were identified in Lake Biwa, the largest lake in Japan. We compiled 109 videos and 122 still‐images of fishes, diving birds and shrimps. The images were cropped from videos taken underwater with animal‐borne video cameras which were mounted on the backs of common carp (Cyprinus carpio). The attribute of each image and its occurrence of organisms were formatted according to the Darwin Core Archive which was developed by the Biodiversity Information Standards (TDWG), and the dataset is available via the Global Biodiversity Information Facility. Our dataset includes records of 10 species, 4 genera, 2 families and 1 infraorder which includes mostly fishes, several birds and a crustacean. The fish records include a threatened endemic fish, the "gengorou‐buna" crucian carp (Carassius cuvieri), and two alien fishes, largemouth bass (Micropterus salmoides) and bluegill sunfish (Lepomis macrochirus). We confirmed several types of intraspecific and interspecific relationships between video‐mounted carp and other organisms; for example, most video‐mounted carp frequently approached or chased conspecifics upon encountering, which sometimes led to two carp feeding side by side. At least three avian species also appeared in the dataset: Eurasian coot (Fulica atra), little grebe (Tachybaptus ruficollis), great crested grebe (Podiceps cristatus), but there was no apparent interaction between carp and these birds. Our underwater videos reveal and highlight the rich biodiversity of the lake today, providing clear evidence for behavior of aquatic organisms under natural conditions. The complete data set for this abstract published in the Data Paper section of the journal is available in electronic format in MetaCat in JaLTER at http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2020-18.1/jalter-en. [ABSTRACT FROM AUTHOR]

Habitat fragmentation, which involves habitat size reduction and isolation, is a major cause of biodiversity decline. However, interest in small isolated habitats has increased among ecosystem managers because these fragments can serve as remnant refuges for unique and/or endangered species in human‐altered landscapes.In a fragmented floodplain of northern Japan, we demonstrate how habitat fragmentation and habitat quality shape the refuges for a unique endangered minnow Rhynchocypris percnurus sachalinensis from biological invasions. We focused on two invasive minnows, topmouth gudgeon Pseudorasbora parva and rosy bitterling Rhodeus ocellatus ocellatus, which are the dominant invasive species. By using a graph theoretical approach and structural equation modelling, we elucidated the relationships among habitat fragmentation, habitat quality and the abundance of invasive minnows with the endangered swamp minnow.We found that the invasion of topmouth gudgeon, which has a high mobility and environmental tolerance, negatively affected swamp minnow populations. The invasive species may outcompete the native species in their overlapping trophic niche.Analyses indicated that habitat fragmentation (decreasing habitat size and connectivity) indirectly and positively affected the population abundance of swamp minnow by reducing the potential for invasion by topmouth gudgeon. We further found an interaction between the indirect effects of habitat fragmentation and local habitat quality: the indirect effects became more apparent in the relatively deeper habitats that were of better quality for natives. This result was likely attributed to the strong control effect of the abiotic stressor. Interspecific competition between the two minnows would be masked in shallow ponds because the native populations are primarily restricted by the abiotic factor, and its abundance is inherently limited regardless of pressure by invaders.Synthesis and applications. In fragmented landscapes, evenly conserving all small fragments within a limited budget is difficult. The change in importance of small isolated ponds across a pond‐depth gradient suggests that conservation priorities for small fragments should be established by considering local habitat quality. Our findings do not justify habitat fragmentation but suggest that both landscape‐scale and local‐scale perspectives synergistically aid in the management of biological invasions in modified habitat networks. [ABSTRACT FROM AUTHOR]

Alien species have invaded worldwide and altered native biodiversity and ecosystem functions. In Lake Biwa, Japan, Micrasterias hardyi—considered an endemic species in Australia—has become one of the major dominant species since 2016. To evaluate long-term and seasonal variations in M. hardyi, we analyzed 20 years of plankton samples from the northern basin of Lake Biwa. The presence of this species was first confirmed in February 2015, and increased for long periods from November 2015 (4.2 cells cm−2) to December 2016 (2.3 × 105 cells cm−2) and from September 2017 (2.0 × 102 cells cm−2) to January 2019 (5.7 × 104 cells cm−2). Particles similar to chytrid zoosporangia were observed and attached to M. hardyi cells. However, the infection rate was low (up to 22.5%), and the infection did not seem to be a major lethal factor. We estimated that M. hardyi was introduced in the early 2000s by simple linear regression of abundance. This result indicates the existence of long time lag from introduction to detection. Moreover, as the propagule pressure to nearby water systems has been high, it is highly probable that M. hardyi has spread to other lakes and ponds via Lake Biwa. [ABSTRACT FROM AUTHOR]

Four species of alien parasites, Dactylogyrus skrjabini Achmerow, 1954, D. hypophthalmichthys Achmerow, 1952, D. wuhuensis Lee, 1960 (Platyhelminthes: Monogenea: Dactylogyridae), and Sinergasilus lieni Yin, 1949 (Crustacea: Copepoda: Ergasilidae), were collected from the gills of the alien cyprinid, the silver carp Hypophthalmichthys molitrix (Valenciennes, 1844) in the Watarase River flowing into the Watarase Retarding Basin, Tochigi Prefecture, central Japan. These alien parasites represent new geographical records from Japan. The generic position of D. skrjabini has been doubted because its dorsal anchor shape is similar to those of Pellucidhaptor spp. (Dactylogyridae), but the species should be assigned to Dactylogyrus based on the phylogenetic analysis of 28S rDNA made in this study. The scientific name "Pseudergasilus polycolpus Markewitsch, 1939" is an incorrect subsequent spelling of P. undulatus Markewitsch, 1940, and S. lieni is the oldest available name that can be applied to the ergasilid found in this study. [ABSTRACT FROM AUTHOR]

Florivores directly decrease the reproductive success of plants by consuming pollen and seeds; thus, plants often have defense mechanisms against florivory. Here, we show that the recurved phyllaries of an agamospermous hybrid dandelion, Taraxacum japonicum × officinale, function as a physical barrier to slug florivory. We allowed Lehmannia valentiana, a European slug naturalized in Japan, to feed on eight pairs of the hybrid dandelion and T. japonicum, a Japanese species with erect phyllaries. Consequently, the slugs only damaged T. platycarpum flowers. The slugs either moved back from recurved phyllaries or spent more than twice as long on recurved than on erect phyllaries. When we removed the recurved phyllaries, the slugs stayed on hybrid and T. japonicum phyllaries for equal lengths of time. In addition to recurved outer phyllaries, the hybrid dandelion has erect inner phyllaries that are longer than those of T. japonicum, which effectively conceal the florets at night protecting them from slug florivory. Using the taxonomic literature, we have confirmed that recurved phyllaries evolved in many species in several parts of Europe, but are rare in East Asia. These findings suggest that European dandelions acquired recurved phyllaries as a defense mechanism under antagonistic coevolution with florivorous slugs, but this coevolution did not occur in East Asia. [ABSTRACT FROM AUTHOR]

The genus Chlorocryptus is revised and two species are recognized: Chlorocryptus purpuratus (Smith, 1852) and C. coreanus (Szépligeti, 1916). Cryptaulax metallicus Szépligeti, 1916, which has been hitherto listed in catalogs as Chlorocryptus fuscipennis Townes et al., 1961, is shown as a new synonym of Chlorocryptus purpuratus. Chlorocryptus purpuratus and C. coreanus are redescribed and illustrated in detail and a key is provided. Chlorocryptus purpuratus is recorded from Japan and Vietnam for the first time and is considered to have recently been introduced into Japan. [ABSTRACT FROM AUTHOR]

An empirical study was conducted on the effects of an introduced predator-prey pair, largemouth bass and bluegill, on pelagic productivity in 22 ponds in central Japan. In the univariate analysis, the effect of fish invasion on chlorophyll concentration was not evident, primarily because this effect was screened by the positive and negative effects of phosphorus availability and the pond area, respectively. A positive effect on chlorophyll concentration was detected in the best statistical model using nutrient availability and pond area as independent factors. Fish invasion decreased the relative biomass of crustaceans to rotifers. This study showed that the invasion of these exotic fishes affected the pelagic community in the pond. [ABSTRACT FROM AUTHOR]

ABSTRACT Topmouth gudgeon ( Pseudorasbora parva) is widely known as a highly invasive freshwater fish and has expanded from East Asia (native range) to Central Asia, Europe and Northern Africa (introduced range). Although the relationship between the occurrence of P. parva and its habitat conditions remains unclear, information on factors affecting its distribution, especially in its native range, is important for predicting its expansion., This study provides primary information on the distribution of P. parva in rivers and agricultural canals in northern Kyushu Island, Japan, where the fish is native. Fuzzy habitat preference models (FHPMs) and Random Forests (RF) were applied to link landscape features to the distribution of P. parva based on field observation data collected from two distinct ecoregions, the north-western (NW) and north-eastern (NE) parts of Kyushu Island., The results show a clear habitat preference of P. parva for areas with a lower elevation, a gentler slope and a smaller number of river-to-river connections as general landscape features across the ecoregions. Weak preferences are observed for sites with a higher number of river-to-canal connections, a higher canal network index, a larger area of paddy fields, a larger residential area, more crop fields and fewer forests and orchards. Of these site-specific features, five landscape features - elevation, slope, canal network index, area of paddy fields, and presence of forests and orchards - are identified as the most important features for predicting the distribution of P. parva., The general and specific habitat preference information, as demonstrated in this study, may be important in biogeography and invasion ecology. Further research is needed to accumulate information for a better understanding of the invasion ecology and the design of improved management and control strategies against P. parva., Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Ankylocythere sinuosa (Rioja, 1942), a symbiotic ostracod native to North America, was found from the Japanese mitten crab Eriocheir japonica (De Haan, 1835), a species native to Japan, collected from a pond in Shizuoka City, Shizuoka Prefecture, central Japan. Introduced North American crayfish Procambarus clarkii (Girard, 1852), which is a host of A. sinuosa in their native range, inhabits ponds sympatrically with Japanese mitten crabs, and it is thought that the ostracods transferred from the exotic crayfish to the native crabs. In recent years, along with the artificial transportation of crayfish around the world, their symbiotic ostracods also have been found on the body surfaces of exotic crayfish in Europe and Japan. However, no studies have confirmed the infestation of exotic ostracods on native crustaceans in the field. A wide range of developmental stages of A. sinuosa from juveniles to adults were found in Japanese mitten crabs, and mating individuals were also found. This strongly suggests that they can reproduce on the body surface of Japanese mitten crabs. In the future, it will be necessary to strengthen measures against alien species to prevent these exotic symbionts from infestating native ecosystems, and we also need to investigate the exact impact of this symbiont on Japanese mitten crabs. [Display omitted] [ABSTRACT FROM AUTHOR]

Japalura polygonata is an arboreal agamid lizard native to the subtropical East Asian islands. Recent studies reported that this species had been introduced to southern and southeastern Kyushu, Japan. Here, we report that this species has also been introduced to Yakushima Island, a Natural World Heritage site located between Kyushu and Amamioshima Island (the northernmost extremity of its native range). Morphological examination of the Yakushima specimens revealed that this lizard population belongs to the nominotypical subspecies (J. p. polygonata), which is endemic to the Amami and Okinawa Groups of the Central Ryukyus, Japan. Observations of the gonadal condition revealed that females collected in April and June possessed shelled eggs in their oviducts. A few juveniles collected in late April and early August were considered hatchlings based on their body size. These lines of evidence strongly suggest that J. p. polygonata has already established a breeding colony on Yakushima Island. Based on the result of tree censuses, the forests where the lizards were found are classified as secondary forests with a primary component. [ABSTRACT FROM AUTHOR]

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Japan's economy depends on the importation of natural resources, and as a result, Japan is subjected to a high risk of biological invasion. Although Japan has quarantine systems to protect ecosystems, agriculture, forestry, fisheries, and human health against alien species, economic globalization has resulted in an ever-increasing risk of invasion. Mite invasion is no exception. Alien species that impact natural ecosystems are regulated in Japan by the Invasive Alien Species Act. However, the law focuses only on visibly recognizable species, so that species too small to see, such as viruses, bacteria, fungi, and mites, are beyond the scope of this law. The Plant Protection Law has limited the introduction of alien pests, including mites, that are harmful to agricultural crops. Recently, the liberalization of global trade policies have increased pressure to loosen regulations on various pests, including spider mites. Infectious diseases and their causative species are quarantined under the Rabies Prevention Law, the Domestic Animal Infectious Diseases Control Law, and the Human Infectious Diseases Control Law, but these laws do not cover wildlife diseases. The most serious problem is that wild reptiles, which can be carriers of ticks and tick-borne diseases, can be freely introduced to Japan. These loopholes in Japan's regulatory system have resulted in mite and tick invasions, which affect not only wildlife communities and human society but also endemism and biological diversity of natural mite populations. [ABSTRACT FROM AUTHOR]

Amorpha fruticosa L., introduced from the eastern part of North and Central America as a revegetation material for artificial slopes, has escaped into riverbeds in Japan, and its negative effects are of concern. In this study, an attempt has been made to clarify the actual extent of escape and establishment of A. fruticosa, through a case study of the Sendaigawa River, Tottori Prefecture, coupled with a survey of national distribution using the National Censuses on River Environments. The autecology of A. fruticosa, including phenology, germination, allelopathy and coppicing ability, was also studied by observation and experiments. The following conclusions were drawn: A. fruticosa preferred sunny sites; the total established area in the study site was 7,500 m; A. fruticosa showed strong coppicing ability; there was lower species diversity in and around areas populated by A. fruticosa; and A. fruticosa has been expanding its area both in the watershed of Sendaigawa River region and nationwide. The authors emphasize the importance of quick control of A. fruticosa. [ABSTRACT FROM AUTHOR]

Japan imports a wide range of arthropods for industrial use and as companion animals. Such imports may threaten ecosystems locally and in their regions of origin. Two iconic insect imports that pose ecological problems are agricultural bumblebees and companion beetles. Colonies of the bumblebee Bombus terrestris have contributed significantly to agricultural production since they were first brought to Japan in the 1990s. But, in their progressive feralisation, they harm populations of native bumblebees through competition, hybridisation, and the introduction of parasites. They also threaten native plant reproduction. The species is currently permitted for agricultural use only in netted greenhouses. Since 2000, imports of companion beetles have thrived, with an estimated market size of many billions of yen. The popularity of rare species has led to a sharp rise in prices, overhunting, and smuggling from their native countries. These exotic species may also become invasive if they escape into nature. There are no clear restrictions on beetle imports, but a government campaign is aimed to improve ethical standards for breeding. In addition, imported tarantulas, centipedes and scorpions are becoming increasingly popular. These species pose similar threats as imported beetles and bees, but the actual state of importation and breeding is difficult to ascertain. Importing insects into Japan can create the following issues: the overexploitation of rare species collected from their native habitats; the traffic in species of which collection and sale is prohibited; the risk that escaped individuals will breed as invasive species; and the introduction of alien microorganisms and parasites.

Previous studies have shown that the dispersal of plant seeds to oceanic islands is largely attributable to birds. However, few studies have assessed the role of adhesive dispersal by birds even though this mechanism has long been recognized as a major vector of seed transport. Some data point to the possibility that adhesive transport by seabirds transfers alien plant seeds in island ecosystems. In the present study, we examined the seed-dispersing ability of seabirds among islands in the oceanic Ogasawara Islands, Japan. We used capture surveys to examine the frequency of seeds adhering to seabirds and tested the salt tolerances of the seeds. The distributions of the plant species were examined and the relationships between plant and seabird distributions were analyzed using generalized linear models. Seeds of nine plant species, including aliens, were detected on 16-32 % of captured seabirds. Seeds included those generally considered to be dispersed by wind or internally transported by birds in their guts. Seeds exposed to NaCl solution isotonic with seawater for up to 8 h suffered little or no loss of viability. Analyses of plant distributions demonstrated positive relationships between the distributions of some plants and seabirds. These results show that seabirds effectively disperse seeds of both native and introduced plant species. This is the first study to comprehensively assess adhesive seed dispersal by seabirds; it provides essential information on long-distance dispersal. [ABSTRACT FROM AUTHOR]

The parasitic plant Parentucellia viscosa has been introduced recently to the Japanese floodplain. Because of its parasitic nature and high fecundity, P. viscosa may well become a major plant invader with a significant impact on floodplain ecosystems. Thus, a knowledge of the host selectivity of P. viscosa will not only provide basic biological information, but will also contribute to the understanding of floodplain vegetation conservation. We evaluated the host selectivity by comparing the observed numbers of haustoria with those expected from the relative below-ground biomass. In addition, we examined the haustorial anatomy to determine whether haustoria are functional, and compared the above-ground biomass of three functional plant groups (grasses, legumes and nonleguminous forbs) in intact and parasite removal quadrats. We found that haustoria were nonrandomly distributed amongst host species, suggesting host preference for Poaceae and Fabaceae. In addition, haustoria attached to certain forbs did not penetrate into the stele. The above-ground biomass of grasses and legumes was increased significantly by the removal of P. viscosa, but the biomass of forbs did not change significantly. These results suggest that host preference depresses the performance of Poaceae and Fabaceae, thus affecting the competitive relationships among plants, meaning that P. viscosa may pose a serious threat to indigenous endangered legumes and grasses. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170, 69-78. [ABSTRACT FROM AUTHOR]

Differences in hypoxia tolerance among three native and three alien bitterling species were examined by means of field surveys and aquarium experiments. I caught fish in minnow traps and measured environmental factors such as dissolved oxygen and current velocity once a month between June and November 2006 at 30 points around Lake Kasumigaura, Japan. In addition, aquarium experiments were carried out to compare aquatic surface respiration thresholds among the bitterling species. Much more individuals of an alien species, Rhodeus ocellatus ocellatus, was caught at the least oxygen range than expected in the field, and showed the highest hypoxia tolerance in the laboratory experiments. Another alien bitterling, Acheilognathus rhombeus, also showed higher hypoxia tolerance than the three native bitterling species. Lake Kasumigaura is well known for eutrophication and water masses with low dissolved oxygen have often been observed there. Differences in hypoxia tolerance among bitterling species might have affected bitterling assemblage structure in Lake Kasumigaura, which is currently characterized by the dominance of R. o. ocellatus. [ABSTRACT FROM AUTHOR]

Abstract: All or a part of a sequence of forest practices (i.e., salvage logging, site preparation, planting crop trees, and weeding) has been implemented after natural disturbances for the rapid re-establishment of tree cover. Forest policies in Japan have recently changed from monocultural planting of coniferous crop trees to planting native broadleaved trees to restore forests and nurture local biodiversity following large windthrows. However, the effects of this new practice on preserving biodiversity, as well as the effects of legacy retention, have never been verified in Asia. Thus, the objective of our research was to compare the effects of legacy retention with plantation after salvaging on the initial stage of vegetation recovery in a blowdown area, specifically focusing on plant species diversity, the occurrence of alien species, and the composition of plant species. Following the analysis of our results, we finally describe appropriate practices to alter disturbed coniferous plantations to bring the species composition closer to that of the original natural mixed forests. A control (A, legacy retention) and three experimental treatment sites (B, salvage logged, site prepared, and Quercus crispula seedlings planted; C, same as B, but weeded once during the summer; and D, residual rows that emerged after establishing sites for planting) were prepared, and quadrats were set. Eleven indicators of the ground condition and the number of vascular plant species, including ferns, were quantified, and the number and abundance of residual and newly colonized plants of the main woody species were estimated. Our main findings were as follows: (1) in unsalvaged sites and residual rows, the diversity of plant species was poor, but a variety of plant species compositions were observed due to the heterogeneous conditions of the ground and ample residual plants; (2) in the planting site, many species appeared, but little variety of the species composition was observed due to the homogeneous condition of the ground and the destruction of residual plants; (3) a large number of alien species emerged in broad, unvegetated areas; (4) the impact of site preparation overwhelmed the impact of salvage logging on the initial recovery of plant species; and (5) to restore a natural mixed forest, a combination of legacy retention and plantation after salvaging would be the most appropriate. [Copyright &y& Elsevier]

The freshwater amphipod Crangonyx floridanus (Amphipoda: Crangonyctidae) is considered to have been recently introduced from North America to Japan, and the recorded sites at which it has been collected now cover nearly all of Japan except for the northern part. In this study, we surveyed further areas outside of its known distribution range, and examined the population genetic structure and the phylogenetic relationships between Japanese and North American populations of this species based on nuclear (18S rRNA) and mitochondrial (COI) DNA sequences. We found that this amphipod has already reached Hokkaido, northernmost Japan, which suggests that it has undergone rapid expansion in a pattern of concentric circles from the central part of Japan. Genetic analysis showed that the Japanese population is genetically homogeneous, in contrast to the genetic diversification of this species seen in North American Crangonyx populations. The process of introducing, establishing, and expanding this amphipod in Japan may be explained as follows. A limited number of individuals from a North American native population were probably inadvertently introduced and established somewhere within the Kanto region. The local population size then increased and its distribution range expanded rapidly across Japan. [ABSTRACT FROM AUTHOR]

In the present paper, the semelid Theora lubrica is recorded for the first time in the Atlantic Ocean, based on numerous specimens collected in the Nervión Estuary and Pasajes Port (Basque coast, south-eastern Bay of Biscay). This species is native to Japan and the Pacific coast of Asia, and has previously been introduced to other areas outside its natural range. Its presence in ports or adjacent areas, suggests that the shipping activity is the most likely pathway of introduction of this alien species in the new settlements. On the Basque coast, the possible impact of T. lubrica on native communities is still uncertain. Future surveys will help us to evaluate its introduction. [ABSTRACT FROM AUTHOR]

The influence of non-native species on native ecosystems is not predicted easily when interspecific interactions are complex. Species removal can result in unexpected and undesired changes to other ecosystem components. I examined whether invasive non-native species may both harm and provide refugia for endangered native species. The invasive non-native plant Casuarina stricta has damaged the native flora and caused decline of the snail fauna on the Ogasawara Islands, Japan. On Anijima in 2006 and 2009, I examined endemic land snails in the genus Ogasawarana. I compared the density of live specimens and frequency of predation scars (from black rats[Rattus rattus] ) on empty shells in native vegetation and Casuarina forests. The density of land snails was greater in native vegetation than in Casuarina forests in 2006. Nevertheless, radical declines in the density of land snails occurred in native vegetation since 2006 in association with increasing predation by black rats. In contrast, abundance of Ogasawarana did not decline in the Casuarina forest, where shells with predation scars from rats were rare. As a result, the density of snails was greater in the Casuarina forest than in native vegetation. Removal of Casuarina was associated with an increased proportion of shells with predation scars from rats and a decrease in the density of Ogasawarana. The thick and dense litter of Casuarina appears to provide refugia for native land snails by protecting them from predation by rats; thus, eradication of rats should precede eradication of Casuarina. Adaptive strategies, particularly those that consider the removal order of non-native species, are crucial to minimizing the unintended effects of eradication on native species. In addition, my results suggested that in some cases a given non-native species can be used to mitigate the impacts of other non-native species on native species. [ABSTRACT FROM AUTHOR]

A total of 263 adult and preadult Chinese temperate bass Lateolabrax sp. caught at 20 locations in the coastal waters of western Japan from October 1999 to September 2008 were used for age, growth and maturity examinations. Examination of marginal increments of transverse sections of otoliths showed that rings (opaque zones) were formed once a year from spring to summer. According to the number of rings and the sampling month, ages were assigned to individuals. For males, we obtained the following von Bertalanffy growth equation: L( t) = 618{1 − e−0.420 ( t + 0.273)}. Females attain sizes over 600 mm SL mainly after 5 years of age and attain sizes of 850–1,000 mm SL at 8–10 years and over 1,100 mm SL about 15 years. Based on histological examinations of gonads and seasonal changes in gonadosomatic indices, potential spawning period was confirmed during mid-October to late January. In males, the minimum size and age at first maturity were estimated as 380 mm SL and 2 years old, respectively, though most males reach sexual maturity at 3–4 years old. Furthermore, female specimens at the mature or developing stages were over 470 mm SL and 4 years old. [ABSTRACT FROM AUTHOR]

Nomoto K, Omiya H, Sugimoto T, Akiba K, Edo K, Higashi S. Potential negative impacts of introduced rainbow trout on endangered Sakhalin taimen through redd disturbance in an agricultural stream, eastern Hokkaido. Ecology of Freshwater Fish 2010: 19: 116–126. © 2009 John Wiley & Sons A/S Sakhalin taimen ( Hucho perryi) populations have decreased in Hokkaido, northernmost Japan, primarily because of overexploitation and habitat degradation. Here we document another threat to this species, that of spawning redd superimposition by artificially introduced rainbow trout ( Oncorhynchus mykiss). Sakhalin taimen and rainbow trout are the only spring-spawning salmonid species in Hokkaido. In 2006–2008, spawning activities of both these species were observed in a Hokkaido stream, and it was determined that their spawning periods overlapped during mid-late April. They also spawned at similar water velocities, depths and substrate compositions. Although female Sakhalin taimen were larger than female rainbow trout, their egg burial depths were nearly identical. During the observation period, rainbow trout redds were approximately five times more abundant than Sakhalin taimen redds, and about 30% of the observed Sakhalin taimen redds were superimposed by rainbow trout redds. The high degree of spatial and temporal overlap in spawning, the similar egg burial depths of both species, and the high proportion of superimposed redds suggest that the introduced rainbow trout impact the endangered Sakhalin taimen in Hokkaido, and possibly, in other areas where the two species occur together. [ABSTRACT FROM AUTHOR]

Hybridization between native and cultivated species is a concern in conservation biology. However, detecting such hybridization and distinguishing true natives from prehistorically naturalized species based on phenotypic characteristics is difficult. Here, we report on introgression between native and prehistorically introduced pear (Pyrus) species in Northern Tohoku (northern end of Honshu Island), Japan. We analyzed 20 microsatellites in 226 wild, seemingly wild, or cultivated materials. Phenetic analysis showed that wild Japanese populations of P. ussuriensis var. ussuriensis in Northern Tohoku, previously considered true natives based on morphology and phytogeography, differed from those in continental Asia, confirming their nativeness. However, Bayesian inference of population structures showed that Japanese P. ussuriensis was genetically admixed with two genetic clusters: true native P. ussuriensis var. ussuriensis and prehistorically introduced P. pyrifolia. Even in the Kitakami Mountains, where true native populations of var. ussuriensis are believed to persist, most wild trees were at least somewhat admixed. Prehistorically introduced then naturalized plants are treated as natives in Japan's conservation management, and some are considered endangered. However, introgression of prehistorically naturalized P. pyrifolia into threatened native P. ussuriensis var. ussuriensis has occurred. This paper examines the implications for conservation management. [ABSTRACT FROM AUTHOR]

We investigated habitat use by introduced raccoons (Procyon lotor) and native raccoon dogs (Nyctereutes Procyonoides albus) in a northern deciduous forest of Japan to examine the relationship between the 2 species. Spatial and temporal habitat use in the forest was monitored using infrared-triggered cameras. We also surveyed environmental factors at 2 spatial scales: at the macrohabitat scale, we examined forest growth stage, forest fragmentation, and distance from a water source; at the microhabitat scale, we examined forest structure, understory vegetation, and beetle abundance. We then analyzed the relationship between environmental factors and habitat use by each species using generalized linear model. Except for fern coverage, most environmental factors at the micro- and macrohabitat scales had different effects on the habitat use of these species. Moreover. the degree of diurnal activity also differed between the species. These spatial and temporal differences in habitat use between raccoons and raccoon dogs provide further evidence that competition between these 2 species may be limited in this area. [ABSTRACT FROM AUTHOR]

• Larch plantations acted as windbreaks and protected native trees from wind. • Larch overstory promoted species abundance and richness of native trees. • No regenerating alien individuals (Larix kaempferi) were observed. • Alien species improved environmental conditions that limit natural regeneration. Restoring forests has recently received considerable attention in the context of sequestering carbon and supporting biodiversity. Although considering alien species as a tool for natural forest restoration still remains controversial, harnessing alien species when they are already present in an ecosystem might result in overall benefits for nature and society. In this study we evaluated whether the presence of an alien tree species supports or hinders the establishment of naturally regenerating forests in Shiretoko National Park, Japan. In particular, we focused on Larix kaempferi , which is widely present yet non-native to the region, and examined how this alien species affects two factors influencing the success of restoration: wind disturbance and deer herbivory. We examined the following effects of L. kaempferi plantations on natural regeneration: (1) the windbreak function for protecting native tree growth and (2) the nursery function to promote the regeneration of native tree saplings and seedlings under high herbivory pressure. We assessed tree height and regeneration, using large-scale remotely sensed data and terrestrial inventory data in five major vegetation types. We found that L. kaempferi plantations can protect native species from predominant winds. Additionally, L. kaempferi canopy cover promoted abundance and species richness in understory saplings and seedlings compared to other vegetation types such as primary and secondary forests, even under excessive browsing pressure. No regenerating L. kaempferi individuals were observed during the field census, suggesting the species is likely not invasive in our study system. The positive relationship between alien tree species and the regeneration of native tree assemblages emphasizes that existing alien species have the potential to act as nurse plants. Our findings imply that the presence of alien species can contribute to natural forest restoration by improving the local environmental conditions for native species in the short-term. Given the multiple ecological and social needs in our changing world, careful consideration is required to evaluate the long-term consequences of alien species. Especially in ecosystems in which alien species have already established, using their positive functions rather than swiftly eradicating them from the landscape might be beneficial for long-term restoration goals. We conclude that managers need to be aware of the context-dependency of alien species to make restoration more effective. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of the three-keeled pond turtle Mauremys reevesii from Japan was analyzed using next-generation sequencing. The mitochondrial genome of M. reevesii was observed to be a circular molecule of 15,528 bp containing 13 protein-coding genes, 22 tRNA genes, and two rRNA genes, along with one A + T-rich control region. The average AT was found to be 61.11%. One extra base was present at the 174th position in the ND3 gene. Molecular phylogenetic analysis revealed that M. reevesii from Japan was few genetically distant from the geographically isolated M. reevesii from South Korea. This turtle might have been exported to Japan from the Korean Peninsula after the Middle Ages. [ABSTRACT FROM AUTHOR]

In this study, we analyzed the complete mitochondrial genome of the invasive Asian hornet Vespa velutina from Japan. The mitochondrial genome of V. velutina was identified as a circular molecule of 16,765 bp, similar to that in other hornet species. It was predicted to contain 13 protein-coding, 20 tRNA, and two rRNA genes, along with one A + T-rich control region. The initiation codons ATC was found in one, ATG in four, ATT in five, and ATA in three genes, while TAA was the termination codon in all these genes. The average AT content of 13 protein-coding was 82%. [ABSTRACT FROM AUTHOR]

The yellow-legged hornet Vespa velutina has become one of the major alien species in European and East Asian countries. As in its homeland, the invading V. velutina is reported as the major predator of honeybees and is becoming a threat to beekeeping in Europe. However, it remains unknown how V. velutina might affect native hornets when it invades Asia, where a large number of Vespa species are distributed. Thus, by analyzing the mitochondrial cytochrome c oxidase subunit I gene, we investigated whether interspecific mating occurs between V. velutina and Japanese native Vespa spp. Our results showed that the alien V. velutina causes reproductive interference in Japanese native hornet Vespa simillima. Forty-three percent of native V. simillima queens had the sperm of V. velutina males, and among the all V. simillima queens analyzed, 28% only had V. velutina sperm. We did not find evidence of V. velutina queens having the sperm of V. simillima males. These findings suggest that reproductive interference by V. velutina males poses a threat to the native V. simillima populations. A decline of V. simillima may also negatively affect other insects that interact with V. simillima.

DNA analysis can reveal the origins and dispersal patterns of invasive species. The green anole Anolis carolinensis is one such alien animal, which has been dispersed widely by humans from its native North America to many Pacific Ocean islands. In the Ogasawara (Bonin) Islands, this anole was recorded from Chichi-jima at the end of the 1960s, and then from Haha-jima in the early 1980s. These two islands are inhabited. In 2013, it was also found on the uninhabited Ani-jima, close to Chichi-jima. Humans are thought to have introduced the anole to Haha-jima, while the mode of introduction to Ani-jima is unknown. To clarify its dispersal patterns within and among these three islands, we assessed the fine-scale population genetic structure using five microsatellite loci. The results show a homogeneous genetic structure within islands, but different genetic structures among islands, suggesting that limited gene flow occurs between islands. The recently established Ani-jima population may have originated from several individuals simultaneously, or by repeated immigration from Chichi-jima. We must consider frequent incursions among these islands to control these invasive lizard populations and prevent their negative impact on native biodiversity.

Calcareous tube polychaetes (family Serpulidae) are notorious biofoulers that are easily transported and introduced to allochthonous habitats. Here we report the recent introduction of Hydroides dianthus (Verrill, 1873) to eastern Japan as its first occurrence in East Asia, probably from European or American coasts. Specimens had been found on artificial hard substrata together with congeners H. ezoensis, H. exaltatus and H. fusicolus in Tokyo Bay, Japan in 2006. The origin, vector, source of introduction and possible impact of H. dianthus on Japanese coasts is discussed from a perspective based on worldwide Hydroides transport. [ABSTRACT FROM PUBLISHER]