In Lake Kasumigaura, artificial increases in water levels to meet the national government's plan for The Kasumigaura Development Project have been implemented since 1996. In the present study, the degree and characteristics of the decrease in emergent vegetation around the lake after the implementation of water-level control were analyzed using data obtained by governmental organizations. An analysis of the change in the width of the emergent vegetation area, which was defined as the distance from the concrete levee to the lake-side end of the emergent vegetation, revealed that the width decreased by 9.54±7.71 m (mean ± standard deviation, n = 34) between 1997 and 2010. The decrease in width was significantly positively correlated with an index of wave strength. An analysis of the pattern of decrease in vegetation area showed that areas dominated by Typha angustifolia and Zizania latifolia, which generally occupy relatively low and sheltered areas of emergent vegetation, had decreased more severely than other types of vegetation. Recently, the government has initiated a new practice for water-level management that is intended to test the compatibility of goals for water use and environmental conservation. Our results suggest that reductions in water levels should be tested as a method for harmonizing water use and vegetation conservation.

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Ligustrum lucidum Ait. is a fast-growing evergreen tree native to China that has been introduced to many countries, mainly for gardens, hedges, and roadside trees. Natural hybridization between exotic L. lucidum and native L. japonicum Thunb. has been a long-term concern in Japan. To reveal the interspecific crossability and the possibility of natural hybridization between these species, we observed flowering phenology, conducted experimental crosses, and ran an AFLP analysis. Peak flowering time was later for L. lucidum than for L. japonicum, and the flowering periods were separated by 2 days. A small number of fruits (seeds) was produced by the experimental crosses between L. japonicum and L. lucidum: the mean fruit set ranged from 0.02 to 0.21 depending on the collection time of pollen grains and pollination configuration. However, AFLP analysis of 365 individuals from four study sites in the Kanto region of Japan clearly demonstrated that none of these individuals was a hybrid. Thus, we conclude that natural hybridization between L. japonicum and L. lucidum does not presently occur in the Kanto region of Japan. Natural hybridization of these species might be prevented by the difference in flowering times or by negative endogenous selection on hybrid seeds or seedlings.

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Throughout the world, agricultural landscapes have replaced natural grasslands and wetlands, often leading to drastic decreases in biodiversity. Recently, conservation-oriented agricultural practices aimed at restoring agricultural ecosystems have been increasingly implemented. The present study investigated the effectiveness of two types of practice, winter paddy flooding and the construction of a small ditch around paddies (a practice called "Ye"), on three amphibian species that use paddies, partially, for breeding (Rana ornativentris, Hynobius nigrescens, and Rana sp.) on Sado Island, Niigata Prefecture, Japan. These two practices are among several conservation-oriented agricultural practices occurring on Sado Island that have the goal of restoring populations of the Crested Ibis (Nipponia nippon). We examined the abundance of the three amphibians in 20 clusters of paddy fields (a total of 159 individual paddy fields) and used generalized linear models (or generalized linear mixed models) and Akaike's information criterion to explain their distributions at two levels (cluster and individual paddy fields). We found that R. ornativentris and R. sp. were positively affected by either or both types of practice. Rana ornativentris responded to different practices at different spatial levels, suggesting the importance of establishing suitable spatial scales. In terms of landscape factors, intermediate levels of surrounding forest cover were necessary for R. ornativentris and H. nigrescens, although the effective spatial scales differed; no landscape factors were important for R. sp. To assess the effectiveness of conservationoriented agricultural practices in heterogeneous landscapes such as Satoyama, we propose that it is necessary to identify species that reflect differences in local potential habitats, rather than seek indicator species that could be used across all landscapes.

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The distribution of submerged macrophytes and the effects of the invasion of exotic animals and plants on their occurrence were examined in small rivers and agricultural canals around Lake Mikata, Fukui, Japan. Four native and two exotic submerged species were recorded in surveys of 59 transects (each 20 m long × the stream width) conducted in 2010 and 2011. Egeria densa Planch., a non-native species, or Hydrilla verticillata (L.f.) Royle, a native species, dominated over 81% of the sites where any submerged species occurred. Both species richness and the cumulative abundance of native submerged plants were significantly lower at the sites where either E. densa or Procambarus clarkii, an exotic crayfish, occurred. Analyses of factors affecting the distribution of submerged plants using generalized linear mixed models (GLMMs) revealed that the occurrence of P. clarkii significantly negatively affected the occurrences of any native species and H. verticillata, but significantly positively affected the distribution of E. densa. These results suggest that the two aliens E. densa and P. clarkii, might facilitate each other. The control of them is necessary for effective conservation of native submerged plants.

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We characterized the influence of patch- and landscape-scale environmental factors on the distribution of the endangered Tokyo Daruma pond frog, Rana porosa porosa, which inhabits paddy fields in suburban areas with developmental expansion. We surveyed paddy fields at 146 sites in the cities of Kunitachi and Fuchu, Tokyo, Japan, for frog-mating calls and environmental factors from 2009-2010. In addition, we calculated the paddy field area and proportion of the area of other paddy fields within a buffer area, which was generated from the peripheral edge of the paddy fields by geographic information systems. The presence of pond frogs was confirmed at 53 sites. Through multiple logistic regression analysis using a generalized linear model as well as all measured patch- and landscape-scale environmental factors, a model comprising an area of paddy fields, vegetation cover in levees, water flow during the non-irrigation period, soil canals, and proportion of the area of paddy fields within a 300-m buffer area, was selected as the best model for describing the occurrence of pond frogs. Every factor within the best model exhibited a positive relationship with the occurrence of pond frogs. These results suggest that both patch- and landscape-scale factors may affect the distribution of pond frogs. The area size of paddy fields is expected to be a particularly important factor affecting the distribution of pond frogs in suburban areas, as paddy fields tend to be fragmented and narrowed by urbanization. Moreover, improving habitat quality via the growth of vegetation in levees, maintaining canal water flow during the non-irrigation period, maintaining soil canals, and preventing habitat fragmentation, would contribute to the conservation of pond frogs.

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We conducted aerial surveys of the sika deer (Cervus nippon yesoensis) population in Akan National Park, eastern Hokkaido, Japan, between 1993 and 2009 to assess the effects of doe hunting and managed culls on deer density. We also surveyed the cover and height of understory plants in exclosure and control sites between 1995 and 2010 to examine changes in the understory vegetation in response to decreasing deer density. The aerial survey showed that deer density decreased from 27.1 ± 10.7 deer/km^2 in 1993 to 9.5 ± 2.5 deer/km^2 in 2009. The data suggest that hunting females and culling herds caused the decrease in deer density, as the population began to decline after doe hunting was allowed in 1994, decreased sharply in response to the deregulation of doe hunting in 1998, and was maintained at a low level after 1999 when managed culls were begun. We analyzed the cover and height of 15 palatable and two unpalatable plants in the understory vegetation. In the sites where hunting and culls were conducted, the cover or height of three palatable plants (Sasa senanensis, Thalictrum ssp., and Trillium ssp.) increased, and an unpalatable plant (Senecio cannabifolius) disappeared in parallel with decreasing deer density. This suggests that management of deer density has allowed understory vegetation to recover by reducing browsing pressure. We conclude that population control of sika deer is an effective measure to foster recovery of understory vegetation damaged by high browsing pressure from deer.

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Conservation ecology is an applied area of ecology aimed at conserving biodiversity and maintaining sound ecosystems, and the discipline is expected to contribute to conservation activities. For this purpose, research in conservation ecology should be properly conducted to support such activities. To understand the current features of research in conservation ecology in Japan, we conducted a meta-analysis of papers published in the Japanese Journal of Conservation Ecology, which has been issued by the Ecological Society of Japan since 1996. The number of papers published in this journal has been increasing, and the authors of these papers have diversified since the first issue. However, certain biases were found in the published studies that were published: researchers tended to carry out studies close to the research institute to which they belonged, and they tended to study plants, mammals, and fish more often than insects and other invertebrates. We present these results and discuss problems that should be resolved in the future to improve research in conservation ecology in Japan.

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We examined ways to maintain and restore the genetic diversity of a residual Primula sieboldii population in the Arakawa Basin, i.e., the Ageo population. A previous study suggested that this population was vulnerable genetically because it comprised nine short-styled genets and one long-styled one. Using eight SSR markers, we detected the ten known genets and a new genet with white petals from 70 samples in this study. Parent analysis showed that the parents of the new genet existed in the Ageo population, based on the genotypes of 31 SSR markers. Under natural conditions, 5.5 seeds were produced per flower, while artificial pollination increased this number more than three-fold. We could not find P. sieboldii seedlings from the soil seed bank. The assignment test revealed that the long-styled genet grown ex situ originated from the Ageo population with high probability and was the best candidate for introduction into the Ageo population. In conclusion, artificial pollination among the existing genets in the Ageo population is the most effective method for maintaining and restoring genetic diversity, and the introduction of the long-styled genet should also be effective.

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The Watarase wetland is a floodplain wetland in central Japan dominated by two tall grasses, Phragmites australis and Miscanthus sacchariflorus, which grow in moist soil. To determine whether topsoil removal for wetland restoration can affect threatened plants in the moist tall grassland, we analyzed the effects of past topsoil removals conducted over the past 48 years to extract soil for civil works projects on the current distribution of threatened species. In our study area (total number of 10 m × 10 m quadrats: n = 11,514), the occurrence frequency of 8 of 26 study species was equal to or greater than 20%, but was less than 10% for the rest of the species. Generalized linear models of the former species revealed that past topsoil removal had significant positive effects on the ranked abundance of six species. Although the removal had significant negative effects on the other two species, their occurrence frequency was more than 50%. Based on these results, as well as occurrence data and other ecological knowledge of threatened species and occurrence data of the invasive species Solidago altissima, we drew an impact potential map to select sites for wetland restoration by topsoil removal.

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To reconstruct the past fish fauna of the Shubuto River System, fish specimens collected from the river system were investigated at the Bihoro Museum (BIHM), the Hakodate City Museum (HCM), the Hokkaido University Museum (HUMZ), and the National Museum of Nature and Science (NSMT). Eighteen local members of the Fisheries Cooperative of Shubuto River and other related organizations were interviewed regarding the past fish fauna of the river system and changes in the abundance of each fish species. Thirteen fish species were re-examined, but it was not possible to re-examine Hucho perryi, which was captured in the Shubuto River in July 1886 and registered at the HCM. Among a total of 42 fish species that had been collected or observed by the interviewers, 34 species were assumed to be reliably identified. The interviewees were concerned about changes in the abundance of protected species that had been identified by regional fishing cooperatives. In particular, reductions in the fish species of floodplain wetlands such as Lethenteron camtschaticum were of concern. Indications of the extinction of the Hucho perryi population and the rapid decline of Lethenteron camtschaticum supported the validity of the action plan in the Kuromatsunai Town Biodiversity Strategy, which targets restoration of floodplain wetlands of the river system. The present study suggested that interviews can provide useful information regarding the decline of fish species that are familiar to many citizens and can complement museum data and literature.

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There can be long time-lags in the biodiversity responses to human-induced landscape changes. The lagged responses in biodiversity due to delayed species extinction and colonization have been called the "extinction debt" and "colonization (or immigration) credit", respectively. Recent studies, particularly from North America and Europe, have demonstrated that extinction and colonization were delayed for years, and even for decades or centuries, after landscape conditions were modified. Species traits, such as dispersal ability and life span, and landscape history appear to be important factors that affect the extent to which biodiversity exhibits a delayed response. To better understand such biodiversity dynamics, it is essential to consider not only the present landscape pattern but also the history of landscape modification due to human activities. There is an urgent need to accumulate data that can be used to predict the long-term dynamics of biodiversity, which can benefit our effort to conserve and maintain regional biodiversity and ecosystem function in the future.

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Lantana camara L. (Verbenaceae), an ornamental plant native to South America, has become widely naturalized in many countries, where it threatens native ecosystems and agriculture. Because of its negative impacts, this species is listed among the top 100 of the World's Worst Invasive Alien Species by IUCN. To date, information regarding the naturalization and distribution of L. camara in Japan is rather limited. This study was undertaken to ascertain the current status of naturalization of L. camara in coastal areas of the Seto Inland Sea and to examine the relationship between its distribution and winter temperature. Coastal areas and islands in Hiroshima Prefecture were selected as the study area. The area was divided into 4000 1 × 1-km meshes using GIS. Five hundred meshes were selected for the field survey by eliminating forested areas where L. camara growth was unlikely. An extensive survey was conducted during May-December 2010; L. camara was found at 186 points, 47 of which were assumed to include naturalized plants. The study area experienced exceptionally cold weather in January 2011, with a monthly mean air temperature below 5℃. However, a field survey conducted during July-November 2011 revealed that most individuals survived the winter. These results suggest that the cold tolerance of L. camara is higher than has been described in previous reports.

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In 2011, the Monitoring Sites 1000 Project conducted by the Biodiversity Center of Japan started monitoring bumblebee assemblages in alpine ecosystems. This report summarizes the results from Daisetsuzan National Park. We observed the species composition of bumblebees and their flower use pattern at the Akadake site from early June to late August. We recorded 473 bumblebees during 12 observation periods consisting of Bombus hypocrita sapporoensis (60%), B. hypnorum koropokkrus (18%), B. beaticola moshkarareppus (14%), B. yezoensis (7%), and B. diversus tersatus (1%). The introduced species, B. terrestris, was not observed. The frequency of bumblebees showed a bimodal pattern in mid-June (by overwintered queens) and after late July (by workers). Bumblebees visited flowers of about 40 plant species. Comparisons of bumblebee assemblages among three locations during the later periods revealed apparent differences in species compositions. B. beaticola was the most common species at the Kurodake site, while B. hypocrita represented more than 90% of the individuals observed at the Hisago-Numa site. One worker of the introduced species B. terrestris was noted at the Hisago-Numa site although it seemed to be an accidental visit to the alpine area from a lowland colony. Continuous monitoring of bumblebee assemblages in alpine sites is necessary to detect global warming impacts on species composition and the expansion of introduced organisms into alpine ecosystems.

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Eradication programs for alien invasive species in Japan have been predominantly conducted by regional volunteers.In recent years, following the introduction of the Invasive Alien Species Act, national and regional governments have led eradication programs for alien invasive species in some regions. Eradication activities led by volunteers sometimes exterminate large numbers of individuals, although the number of participants during a program can be highly variable. In contrast, eradication activities run by government-employed workers can achieve stable and predictable eradication targets but often depend on sufficient funding. In this report, we quantified the efficiency of eradication activities led by volunteers or government-employed workers aimed at eradicating Rudbeckia laciniata from national parks in Japan. Activities led by volunteers eradicated 1,090 stems/event on average, but the efficiency was highly variable. The maximum removal was 7,500 stems at an event in Hakone National Park. On the other hand, activities led by government-employed workers achieved stable eradication efficiencies (1,650 stems/event at the maximum, with an average of 637 stems/event in Hakone). To achieve efficient and certain eradication, collaborations between government and volunteers are essential.

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At Lake Kasumigaura, water levels have been maintained at 1.3 m in winter and 1.1 m in all other seasons to meet the national government's plan for The Kasumigaura Development Project since 1996. Although the winter increase was tentatively discontinued in 2000, it resumed in 2003 as an "Experimental water level management" program that was run by the government. The stated aim of this management program is "to harmonize the water usage and conservation of lake nature". However, recent scientific knowledge suggests that reductions in water levels may also achieve this goal and should, therefore, be tested.

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