Emergency control of Plum pox virus (PPV; genus Potyvirus) has been conducted in Japan since its first discovery in 2009. Symptoms emerge about 3 years after the transmission of PPV to plants by aphids. Therefore, to eradicate PPV, it is necessary to remove all potential host plants within a spatial area that has a significant probability of infection during the 3-year incubation period. Based on empirical studies, a radius of 500 m was adopted as the emergency control range in 2013. In the current study, we used a gamma model to estimate aphid dispersal by considering non-random aphid movement patterns. The probability of infection at a distance of 500 m was estimated to be about 0.5%, indicating that the currently adopted emergency control range is appropriate. We further estimated that the minimum distance to ensure a basic disease reproduction rate of < 1 was about 607 m, assuming that all potential host plants within that distance are removed. An additional buffer zone of 500 m would be effective for maintaining areas of low pest prevalence (ALPPs) against PPV.

The abundance of Pacific bluefin tuna Thunnus orientalis has decreased markedly in recent years and is subject to strict international fishing quotas. The quotas for purse seine, coastal, and other fisheries are allocated domestically. The rules for domestic allocation are unclear and in some areas the set net fishery greatly exceeded the limit in the 2017/2018 season. The allocation was decided before the allocation method was agreed upon among stakeholders. In this paper, we discuss the grounds for strict quota limitation and how to determine domestic quotas, their problems, and future prospects. By international agreement, there has been a drastic decrease in comparison with the past stock abundance. Japan agreed to the strict catch limit because they expected more recruits to be born in 2015 and 2016. We propose a population reproductive potential that is defined as the sum of the reproductive values of all individuals as a more reasonable indicator of stock abundance than the spawning stock biomass that is used for international fisheries management. It is rational to prioritise coastal fisheries when the stock is low and to allocate more to offshore fisheries when the stock is high to increase the overall catch. In theory, allowing transfer of the catch quota will decrease the release of high-price tuna, while keeping the total quota.

Maintaining wildlife populations requires the creation of management strategies and implementation of conservation or stabilisation measures. In Japan, sika deer management is driven by two management plans created by separate administrative bodies. The 'Protection and Control of Wild Birds and Mammals and Hunting Management Law' implemented by the Ministry of the Environment, was designed to allow prefectural governments to manage sika deer over large spatial scales, whereas the 'Act on Special Measures for Prevention of Damage Related to Agriculture, Forestry, and Fisheries Caused by Wildlife' implemented by the Ministry of Agriculture, Forestry, and Fisheries, is tasked with creating a budget covering all practical measures for grazing damage mitigation at the municipal level. Although the Ministry of the Environment is responsible for wildlife management in Hokkaido, it cannot directly examine or influence measures taken by municipalities because they are financially controlled by the Ministry of Agriculture, Forestry, and Fisheries. To foster a comprehensive sika deer management system, we held meetings in six subprefectures, gathering representatives from multiple administrative levels (prefecture to municipality) in agriculture and forestry departments to exchange opinions about relevant administrative issues. These meetings demonstrated the need for better communication and collaboration to create stronger links between the administrative bodies that create and execute sika deer population management plans so as to ensure sustainable populations in Japan.

Wildlife managers need to establish proper management units based on the biological organisms and/or habitats of interest, and management entities should correspond to the spatial scales of the management units. An expanding management spatial scale is associated with an increasing number of legal requirements and larger management entities, which result in a complicated system. For example, to eradicate the plum pox virus, the roles and responsibilities of national and local governments are clearly demarcated, with small gaps between management and administrative units. Conversely, domestic quotas for the Pacific bluefin tuna, which has a reduced stock abundance, are determined according to strict international fishing regulations. Only recently have rational allocation methods for coastal and offshore fisheries been examined; however, the spatial influences of the entities that manage these fisheries correspond to the ranges of the managed fisheries. Wild populations of the great cormorant and sika deer are distributed widely across municipal and prefectural boundaries. These populations have been culled as part of nuisance control by municipalities and prefectures. However, the management spatial jurisdiction and the roles and responsibilities of each municipality and prefecture are not clearly defined. To address this issue, nuisance control by municipalities should be the top priority, and population control by prefectures should be conducted in cooperation with the relevant municipalities under the subsidiarity principle.

In Japan, the once endangered Great Cormorant (Phalacrocorax carbo) currently damages inland water fisheries and forests where they nest or roost. Since control at the breeding colonies and roosts should be done in a systematic manner, with regional cooperation, to avoid shifting nest and roost sites that will cause new damage, the Ministry of the Environment and the Union of Kansai Governments are managing this species over wide areas. Shiga Prefecture successfully decreased the cormorant population from ＞70,000 to ＜10,000 by sharpshooting. As the next step, discussions on a watershed ecosystem basis have been used to manage the distribution of colonies and roosts in the prefecture, ensuring consistency with the prefecture management plan for the species. Cooperation with the Fishery and Environment Departments in Shiga Prefecture and their specialist personnel makes such discussions more productive. Although few prefectures have cormorant management plans, workshops run by the Ministry of the Environment are helping local government officers to become able to address the issues. It is hoped that improving the watershed ecosystem services will lead to the coexistence of humans and cormorants, a goal of cormorant management.

Mutualistic biological interaction networks are thought to be essential targets for monitoring the effects of anthropogenic environmental changes on biodiversity and ecosystem function. The aim of the present study was to evaluate the feasibility of citizen science monitoring of the mutualistic network between butterflies and plants in Tokyo, Japan. We analysed 4,401 photograph-derived data points describing butterfly visits to flower and tree sap of identified plant species during 2015. 2017. These data were reported to the internet-based participatory butterfly monitoring program Butterflies in Tokyo, which is operated jointly by the regional consumer co-operative Pal-system Tokyo and conservation ecology and data engineering scientists. We performed hierarchical clustering analysis and drew a network graph according to the similarity of plant species visited by the butterflies. We categorised the butterflies into six groups including four guilds or specialist groups, one generalist plant utilisation group, and one group comprising ambiguous species. The results of this study demonstrate the feasibility of this citizen science program for monitoring the mutualistic network of butterflies and plants in Tokyo and provide baseline information for future monitoring.

Offshore wind energy is a renewable energy source that offers an opportunity to reduce greenhouse gas emissions while increasing energy security. However, many ecologists have suggested that offshore wind farms may have severe negative impacts on wildlife, especially seabirds. Thus, balancing seabird conservation with human energy demands is necessary when developing wind farms. Bird sensitivity mapping is a powerful and practical tool that can determine turbine collision risk within specific areas; however, sensitivity maps have seldom been generated for seabirds. Focusing on the Slaty-backed gull (Larus schistisagus), a red-listed species that often collides with wind turbines, we determined factors affecting habitat selection with the goal of reducing negative impacts of offshore wind farms. We then generated a sensitivity map using habitat modeling. GPS loggers set to record at 5-minute intervals between June and August 2018 were attached to six Slaty-backed gulls residing in Ochiishi Bay, Nemuro Prefecture, Japan. A Gaussian mixed model indicated that habitat selection was related to food availability (as determined by sea surface temperature and chlorophyll a content) and distance to the nest site. Sea surface temperature and chlorophyll a content were positively related area visitation frequency of Slaty-backed gulls, whereas distance to nest site was negatively correlated. Moreover, area visitation frequency was unchanged when the distance from the nest site was > 25 km. The sensitivity map indicated that areas both near and far from nest sites with potentially abundant food resources were high-risk areas with respect to turbine collisions for Slaty-backed gulls. Based on these results, we advocate the use of sensitivity mapping to reduce interactions between offshore wind farms and seabirds, especially for species that often forage far from their nest sites.

Insecticides are chemicals used in agriculture that may have negative impacts on human health and the survival of non-target organisms. Many amphibian species in Japan depend on paddy fields during their early development, which overlaps with rice cultivation and insecticide application to paddy fields. These early developmental stages include organ formation, when insecticide exposure could cause embryological disturbances and have serious effects on larval growth and survival. In this study, we focused on two amphibian species, the Japanese tree frog (Hyla japonica) and the Montane brown frog (Rana ornativentris) as indicator species of paddy ecosystems. We examined the toxicities of three insecticides: clothianidin (a neonictinoid), cartap (a nereistoxin), and chlorantraniliprole (a diamide). We measured larval sensitivity to these insecticides and differences in toxicity between the active ingredients and formulations. Our results indicate that exposure to cartap increased the malformation and the mortality rates in both frog species, while no teratogenicity was observed in clothianidin and chlorantraniliprole. The sensitivity to cartap differed between the two frog species; in Montane brown frogs, deformity and mortality rates occurred at higher concentrations (0.2 mg/L) than in Japanese tree frogs (0.02 mg/L). Cartap exposure caused deformities including spinal bend and spinal blisters in both species, and albinism in the Japanese tree frog. The spinal bends occurred after exposure to concentrations of 0.2 mg/L cartap in the Montane brown frogs and 0.02 mg/L cartap in Japanese tree frogs. Blisters developed after exposure to a concentration of 2 mg/L cartap in both species. Experimental treatments resulted in a greater incidence of spinal bend and a smaller incidence of spinal blisters, which occurred after exposure to the cartap formulation rather than exposure to a single active ingredient. Our results indicate that cartap has a serious impact on the early development of paddy-dwelling frogs, especially Japanese tree frogs. Spinal bends and albinism caused by cartap exposure can seriously effect larval survival and may occur at the concentrations used in standard applications of cartap in paddy fields.

Research has shown that evolution occurs on the same timescales as changes in population size, and that gene frequency and population dynamics interact with each other. A growing recognition of such eco-evolutionary dynamics highlights a need to study how ecological and evolutionary interactions play out on timescales most relevant to conservation and management. However, the roles of evolution in the outcomes of conservation and ecosystem management are not well understood. This review aims to illustrate the importance of considering evolutionary perspectives in conservation ecology when faced with anthropogenic environmental changes such as climate change, habitat fragmentation, and alien species. We describe the fundamental processes underlying evolution and discuss how evolutionary approaches affect conservation outcomes, as well as specific measures and future prospects for improving conservation and ecosystem management.

Mangroves are salt-tolerant terrestrial plants that grow in tropical and subtropical estuary areas. In a mangrove ecosystem, the trees provide food resources and habitat for various species. Benthic animals may contribute to this ecosystem’s materials cycle, because most are thought to consume organic material produced by mangroves. In this study, the food web structure of benthic animals in mangrove forests was investigated using stable isotopes and compared between Kiire mangroves in Kagoshima City and Sumiyo mangroves on Amami-Oshima Island. The former were replanted in the 1700s and are located in a temperate area that is almost at the northern limit of mangroves, while the latter comprise a natural stand in a subtropical area. We found that benthic consumers, mainly gastropods and crustaceans, consumed mangrove materials in Sumiyo, whereas in Kiire they consumed algae or phytoplankton. The food web structure in Kiire did not change after simultaneous defoliation caused by a cold wave in January 2016, when the constant supply of mangrove leaves disappeared. These results imply that the Kiire mangrove trees do not function as the basis of a food web but rather as a habitat provider.

We investigated the flora and vegetation of a coastal sandbar forest in Honshu, Japan, soon after mounding and afforestation as part of infrastructure reconstruction following the Great East Japan Earthquake. Our objective was to estimate plant diversity following these management practices. The mounds at the study site were characterised by low vegetation and high bare-soil cover, and were dominated by annual or perennial herbs associated with early secondary succession. We found a small number of woody plants and only one tree species, Pinus thunbergii. Three coastal plant species were found, all of which had low rates of cover. Approximately 40% of all recorded taxa were naturalised species (23 taxa), all of which also had low rates of cover. In total, we recorded 58 vascular plant taxa, many of which had been reported from the coastal forest or roadside areas on the sandbar prior to the earthquake. However, the mounding materials comprising sand obtained from sandstone in the adjacent hills probably contained few buried seeds. We suggest that many of the taxa we observed had been transported from neighbouring areas. Since this study was limited to a small area, we suggest that further work is needed to understand fully the effects of the infrastructure reconstruction activities, such as mounding, that were used across eastern Japan following the earthquake.

Spring-fed waters have special environmental conditions and sets of unique fauna and flora. Thus, preservation of spring-fed wetlands is important to the conservation of biodiversity in Japan. Recently, invasions of alien aquatic plants have been reported in some such waters. Aquatic vascular plants were surveyed at 201 sites in spring-fed rivers, streams, and ponds in 26 prefectures of Honshu, Shikoku, Kyushu, and the Ryukyu Islands. As a result, 69 species were identified, including submerged or floating-leaved forms of terrestrial plants, from 165 sites. Among these, 20 alien species were recorded from 114 sites, and extensive invasion of alien species into spring-fed waters in Japan was documented. The most frequently recorded alien species were Nasturtium officinale R. Br. (including N. × sterile (Airy Shaw) Oefel.), Veronica anagallis-aquatica L., and Elodea nuttallii (Planch.) St. John, followed by Callitriche stagnalis Scop., Egeria densa Planch., and Iris pseudacorus L. The ecological risks posed by these alien aquatic macrophytes are discussed with special reference to environmental conditions specific to spring-fed waters. Some future subjects are proposed to promote surveys of the present status of alien aquatic plants and native flora, including mosses, in spring-fed waters throughout Japan.

Some dragonflies in East Asia have adapted to traditional paddy cultivation by matching their phenology to the paddy growth cycle, water regime, and the forest and grassland landscapes surrounding the paddy fields. An endangered dragonfly, Sympertrum uniforme, lays eggs in reservoirs that supply water to paddy fields and is highly influenced by traditional water management regimes. Here, we studied the effects of water management of reservoirs on S. uniforme in Ehime Prefecture, Japan. The water-level management regimes and adult abundances (mature and immature) were surveyed at selected reservoirs. Samples of sand and gravel were collected at each reservoir just below the maximum water level. The samples were kept dry throughout the winter, watered the next spring, and larvae that hatched were counted. Many larvae hatched from the sand and gravel samples, which were collected from areas that dry out in winter. For one reservoir, although the water management regime and spawning rate were similar to those at other reservoirs, few larvae hatched, and the adult emergence rate was low.

The tri-spine horseshoe crab Tachypleus tridentatus is endangered on the coasts of East Asia. A recovery program is being conducted in Kasaoka City, Okayama Prefecture, on the eastern Seto Inland Sea, Japan, using laboratory-bred horseshoe crabs released on the Kohnoshima tidal flat. To determine the most suitable instar stage for wild release, we analysed the distribution of carapace widths of juvenile horseshoe crabs observed on the tidal flat and estimated the growth rate at each instar. The results showed that juveniles grew up to the 9th instar stage in the 5th year after hatching on the tidal flat. Juveniles kept in our laboratory were smaller than juveniles living on the tidal flat, particularly at each of the 6.9th instar stages. We presume that poor food quality and high rearing density in captivity caused the lower growth rate of laboratory-reared juvenile horseshoe crabs. Releasing juveniles at early stages (< 5th instar) will improve growth and the success of the recovery program. Conservation measures will be required to maintain a sustainable wild population of horseshoe crabs in Kasaoka without relying on artificial releases.

Eradicating or reducing populations of alien invasive species is exceptionally difficult once they have become established. However, successful instances of eradication and reduction are becoming more common with ongoing refinement and advancement in management strategies. In Hakone, Kanagawa Prefecture, Japan, attempts to eradicate the alien invasive plant Rudbeckia laciniata L. have been in progress over the past decade with a recent dramatic reduction in population density. Here, we report the processes used over this decade-long eradication campaign and discuss the key factors promoting success based on monitoring records. We believe that the lessons learned in our region will be useful for similar invasive species management in other regions.

In recent years, community-based participatory research, especially involving the mass collection of photographs of local wild animals and plants with GPS information, has become increasingly popular. However, biases related to differences in scientific experience between citizens and specialists have not yet been assessed. A few studies have objectively evaluated the trends and characteristics of photographs submitted by citizens. ‘Finding salmon’, operated by the Sapporo Wild Salmon Project, is one such citizen research project, but it also includes photographs taken by salmon experts. This study investigated potential biases pertaining to subjects, locations, and timings by comparing the data of citizens and experts. The results suggested no significant bias in subjects, but citizen photographs tended to be taken near a bridge. In addition, while expert photographs covered most of the salmon spawning season, those of citizens tended to be taken around the peak of migration. Future studies of community-based participatory research need to consider these biases to utilise data from citizens fully.