Biodiversity plays a key role for humanity and, therefore, effective biodiversity management is essential. The biodiversity of Japanese national parks varies greatly, reflecting differences in environmental conditions such as air and water temperatures, and management is species- and community-specific. In this study, we focus on the management of reef-building corals, macroalgae and seagrasses, which shape the underwater landscape. The purpose of this study was to summarise the perception of these communities as resources in national parks, to clarify what conservation and monitoring measures are implemented for these communities, to discuss their vulnerability to climate change, and to suggest management adaptations that should be taken. Our results show that the Ministry of the Environment implemented many conservation measures for reef-building corals, such as population control of predators of reef-building corals. The number of restricted reef-building coral species was much higher than that of macroalgae and seagrass in each national park, and this pattern was more pronounced in national parks located at lower latitudes. Although macroalgae and seagrasses were listed as restricted species in some national parks, far fewer monitoring and conservation measures were implemented for these species in comparison to reef-building corals. Based on these results, we summarised the characteristics and issues of each national park. Reef-building corals are vulnerable to rising water temperatures and are expanding their distribution area northwards. Therefore, we expect that many parks will need to revise their regulated species lists and increase conservation measures in the future. In some parks, there is a gap between the present distribution of reef-building corals and their conservation management, and it is important to implement projects to fill this gap. Regarding macroalgae and seagrasses, the challenge to define their value and to implement continuous monitoring and conservation measures for these species needs to be addressed.
In Japan, to maintain populations of organisms at high risk of extinction, the Act on the Conservation of Endangered Species of Wild Fauna and Flora deems them “national endangered species of wild fauna and flora”. These species require conservation genetics studies to prevent inbreeding depression and genetic disturbance. Such studies have examined many “national endangered species of wild fauna and flora”, accumulating genetic information on them. However, most of the published papers have been written in English, which makes them difficult to use for local conservation activities. Therefore, we report the accumulated genetic information on “nationally endangered species of wild fauna and flora” for use in local conservation activities. We classified the genetic information into five categories: “genetic diversity and genetic structure”, “genome (including organelle genomes)”, “genetic markers”, “inbreeding depression and deleterious genes”, and “other”. The proportion of accumulated genetic information was high for vertebrate species and low for invertebrate species. Many scientific papers examined vascular plant species, but the proportion of species was low due to the large number of species. With the recent rise in high-throughput sequencing, genome-level methods make it possible to obtain large amounts of genetic information inexpensively. We also review the analysis methods and discuss future prospects for conservation genetics studies.
Recent decades have brought increased interest in ecosystem-based disaster risk reduction (Eco-DRR) as a framework for modern-day infrastructure due to lower start-up and maintenance costs relative to traditional disaster mitigation infrastructure, and the potential benefits of associated ecosystem services. Paddy farming, a dominant agricultural practice in Asia, has been evaluated as an Eco-DRR approach to reducing flooding. The conservation of paddy fields in areas of high flood risk appears to be effective for controlling and reducing the impacts of flooding. Here, we aimed to identify areas of high flood risk along the Nakagawa River, Japan, based on the activity of Typhoon 19, which passed through the area in 2019, using a randomised null model approach. We found that confluence areas along the Nakagawa River were the most vulnerable to flooding, although we note that the number of flood records was limited. There were large areas of hydrophilic vegetation around these confluences, which suggests that flooding may contribute to regional biodiversity. There was generally less cover of paddy fields and urbanised areas around these confluences relative to the entire study area, but these differences were not substantial. Conserving paddy fields around confluences in the Nakagawa River may provide a variety of ecosystem services, including disaster risk reduction, biodiversity conservation, and food production.
The North American signal crayfish Pacifastacus leniusculus was newly found in six waterbodies of Nagano Prefecture, central Japan, from 2011 to 2020. The waterbodies with new introductions included reservoirs, farm ponds and low-gradient streams within the altitude range of 670 - 1300 m. Analyses of ectosymbiotic branchiobdellidan (Annelida: Clitellata) species composition and mitochondrial DNA sequences of the crayfish suggest that the new invasions arose due to translocation via multiple pathways from inside and outside of Nagano Prefecture. Efforts to eradicate the newly established signal crayfish populations should be undertaken. At the same time, further efforts to stop illegal stocking are needed to prevent range expansions of signal crayfish.
Aquatic systems are highly sensitive to anthropogenic effects and have suffered from invasion by non-native species in recent decades. Remote sensing products, used at appropriate spatial scales, are powerful tools for monitoring dynamics in aquatic vegetation and conserving native species. Here, I propose a high-resolution mapping method for aquatic vegetation using pole photogrammetry, and demonstrate its efficacy by mapping vegetation around a natural spring at the confluence of the Inukai and Katsura Rivers in the Yodo River watershed, Japan. A camera, attached to a stabiliser, was used to photograph vegetation. Captured videos were processed using Structure-from- Motion-Multi-view Stereo (SfM-MVS) photogrammetry to create orthomosaic images, from which species polygons were interpreted visually. The imagery resolution was adequate to identify vegetation to the species level. Therefore, it was possible to determine species cover and distribution within the study site using the orthorectified mosaic images. The resulting vegetation maps are highly valuable for ecosystem management and conservation in the study area, especially given that the spring area has high aquatic plant species richness, but has been experiencing an increase in non-native species cover.
The ice goby Leucopsarion petersii is decreasing in abundance and was recently classified as a vulnerable species by the Ministry of the Environment of Japan. Although most of its life history is spent in the ocean, L. petersii is an anadromous fish that ascends rivers during the spawning season and spawns downstream. Much information on L. petersii has been collected from its river habitats; however, its ocean habitats remain poorly understood. Therefore, in this study, we investigated the spatiotemporal distribution of L. petersii at five survey sites in Obama Bay, Japan. Surveys were conducted in early summer (7 June, 2018), summer (26 July, 2018), autumn (18 October, 2018), winter (31 January, 2019), and early spring (21 February, 2019). Beam trawling was conducted from a ship, for periods of a few minutes; a total of 274 individuals were caught throughout the study period. A generalised linear model was used to detect seasonal and site effects, with number of individuals as an objective variable, and season and sampling location as explanatory variables. A negative binomial distribution was assumed, and we corrected for differences in sampling effort. The maximum catch per unit effort occurred in autumn, with significant differences among sampling sites; however, we detected no significant effect of environment or distance from the river mouth, due to the limited number of sampling sites used in this study.
The small dragonfly Nannophya pygmaea Rambur 1842 (Libellulidae) inhabits spring-fed marshes in Kani, Japan. To support the conservation of the genetic diversity of the N. pygmaea population, its genetic diversity and genetic differentiation were assessed by comparing the sequences of a 658-bp-long fragment of the mitochondrial DNA cytochrome c oxidase subunit I gene. Based on DNA polymorphisms in the gene, the 294 N. pygmaea specimens collected in this study were divided into eight haplotypes. There was no significant correlation between haplotype diversity and area and slope of the marshes, pH and electric conductivity of surface water, or vegetation height around the marshes. Furthermore, there was no significant genetic differentiation between marshes, and the N. pygmaea population was considered to be a single population that migrates among marshes without gene exchange restriction. To maintain the genetic diversity of the N. pygmaea population, it is necessary to prevent the decline of habitat suitability and the loss of marshes, which could limit gene exchange. Therefore, we will continue to monitor the water quality and sediment inflow of the marshes and remove accumulated sediment and plants that invade from the surrounding area, as well as periodically evaluate the genetic diversity of the N. pygmaea population.
Solfatara fields, which form around fumaroles (vents) in hot springs and volcanoes, are characterised by extreme environmental conditions, including volcanic gas emission, low pH, and high aluminum content in soils. Very few plant species are capable of tolerating these conditions. Recently, Andropogon virginicus L. (Poaceae), an exotic grass native to North America, has colonised solfatara fields in Kyushu, Japan, but these populations have not been well assessed. We assessed the status of A. virginicus in 13 solfatara fields in Kyushu and its distribution relative to soil pH. We examined further germination and seedling growth under low pH conditions using laboratory experiments. We found that A. virginicus was present in 6 of the 13 survey locations, and that its distribution was partially overlapping with that of Fimbristylis dichotoma (L.) Vahl subsp. podocarpa (Nees et Meyen) T. Koyama (Cyperaceae), an endangered species endemic to Kyushu. Laboratory experiments indicated that germination and seedling growth were uninhibited at a pH of 3, suggesting high potential for establishment of A. virginicus in acidic soils. Thus, the invasion of A. virginicus may endanger endemic species and pose a threat to the unique landscapes of solfatara fields. We suggest that prompt action be taken to control the spread of this species.
This study examined the effects of natural predators and insecticides for pest control to achieve effective integrated pest/biodiversity management. Four 7-m2 experimental plots were set in a suburban paddy field, with or without netting (20-mm mesh to exclude large flying predators) or pyrethroid insecticide application. Insecticide application decreased the abundance of Hemiptera, Orthoptera, Coleoptera, and Diptera and netting increased those of Hemiptera and Orthoptera. Hemipteran insects, which are main pests of rice plants, comprised 85% of the total insect abundance. With insecticide application, the abundance of Nilaparvata lugens decreased, with netting the abundance of Laodelphax striatellus increased and with both, the abundance of Nephotettix cincticeps, Recilia dorsalis, Psammotettix striatus, and Empoasca vitis changed. Our simple experiment showed that flying predators were as effective at reducing rice pest populations as insecticide application, whereas insecticide reduced non-pest insect populations.
Human activity has caused habitat loss and degraded ecosystem function in both marine and estuarine systems worldwide. There is an urgent need for restoration of these coastal ecosystems. Mikata-goko, a series of five lakes in Fukui Prefecture, Japan, has a long history of anthropogenic degradation; thus, habitat restoration is a key issue in the area. The Mikata-goko Nature Restoration Committee, formed in 2011, has set multiple conservation targets in three theme areas: conserving and restoring biodiversity, revitalising the local community using ecosystem services, and maintaining rich local cultures and traditions for future generations. Since 2016, a working group has focused on natural coastline restoration using workshops and active research projects. Their results and suggestions were summarised as a report in 2020. In accordance with the guidance provided by the report, a working group conducted beach nourishment at three sites, two in Kugushi-ko lagoon and one in Suigetsu-ko, in an effort to conserve the Shijimi clam. All sites were formerly natural beaches; added sediment was dredged from inflowing rivers in 2020-21. This report summarises the beach nourishment project, as well as other practices conducted under the coastal habitat restoration program for Mikata-goko.