We investigated the use of various types of bridge as day roosts by several species of bats in Obihiro, Hokkaido. Eleven species belonging to six genera were found in the study area. Six species belonging to two genera used bridges as day roosts. The bridges were categorized into three types according to their structural characteristics. Bridges with flat undersurfaces were classed as flat-bottomed bridges; those with intersecting beams that formed deep cavities or cells on the undersurface were classed as cell bridges; and those with narrow parallel cavities on the undersurface were classed as stria bridges. Only cell and stria bridges were used as day roosts. Cell bridges were used more frequently than stria bridges. Bats created colonies in cell bridges, whereas almost all of the stria bridges were used as solitary roosts, particularly by juveniles. More species used stria bridges than used cell bridges. These results suggest that the type of bridge used by bats as day roosts depends on the bats' breeding stage. An increase in the use combined floorboard bridges, a new type of structure, may reduce the number of bridges potentially used by bats as day roosts.

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Robinia pseudoacacia is an invasive alien tall tree species in Japan. This study evaluated the spatial distribution of R. pseudoacacia and its historical background in Bibai, a former coalmining region in central Hokkaido. Using satellite images and a field survey, the area of R. pseudoacacia stands totaled 0.989km^2 in the 100km^2 investigated (10×10km). Interpreting historical aerial photographs taken in 1962, 1973, 1982, and 1993, the location of each R. pseudoacacia stand was classified into six types of land use. Historically, much of the land was once cut or used for crops. Cut forests were reforested quickly between 1962 and 1972. Crop fields and coalmines were reforested gradually between 1962 and 1993. Of the forest without R. pseudoacacia that neighbored Robinia stands, forests that had not been cut or otherwise used constituted 25.0%, which is significantly greater than the 11.7% containing Robinia stands. This implies that it is difficult for Robinia to spread into undisturbed forests. The results strongly suggest that the lack of management of plantations, abandoned crop fields, and vacant sites at former coalmines contributed to the rapid spread of R. pseudoacacia in the study area.

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The population of Ligustrum lucidum Ait., a horticultural plant originating from China, has recently been increasing in urban river environments in Japan. This study sought to clarify how flood disturbances affect the expansion of the L. lucidum population in urban riparian environments. We investigated the number of individuals, size, fructification, and the condition of fallen L. lucidum before and after a flood in the Inagawa River, Hyogo Prefecture, western Japan. One-third of the adult trees were washed away in the flood, but the number of seedlings increased the year after the flood. The flood felled one-third of the trees whose trunks were over one meter long. The percentage of fruit-bearing individuals decreased from 46.8 to 24.5% in the year following the flood. The year following the flood, 37.5% of the standing trees and 4.5% of the flood-felled trees produced berries. These results suggest that flooding has a weak negative effect on the expansion of the L. lucidum population in urban river environments.

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Habitat suitability for medaka, Oryzias latipes, was predicted based on presence data for southern Ibaraki Prefecture, Japan, in the late 1960s. Land use on maps was used as an environmental variable for describing the niche of medaka. A multivariate analysis showed that the distribution of rice fields delineated the niche most strongly in a positive way. The distribution of urban areas was the second strongest variable, and also had a positive effect. Cropland, secondary grassland, and pine forest were also used in the niche description. A cross-validation test indicated that the prediction was reliable, as there was a significant correlation between the habitat suitability and the relative frequency of presence data among grids of each class of habitat. Given that a large area of rice fields has been altered, to allow mechanical cultivation, in such a way that medaka habitat has been destroyed, and the present distribution of medaka is limited and difficult to determine, the collection of such geographical information is encouraged in order to construct a present habitat suitability map for medaka.

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The breeding success of the Japanese Golden eagle, Aquila chrysaetos japonica, designated a precious natural product and a class IB endangered species in Japan, has declined rapidly during the last three decades. Of the likely factors causing this breeding failure, a rapid decrease in the foraging habitat, caused by an increase in coniferous plantations with closed canopies, was recently noted. In 2002, the forest agency attempted to make forest gaps, using line-thinning, to form a foraging habitat for Golden eagles in order to improve their breeding success in the Kitakami Plateau, in Iwate prefecture. In order to evaluate the efficacy of line-thinning in creating a foraging site for Golden eagles, we determined numbers of hares and snakes, which are the main prey of the Golden eagle in this region, and the foraging activities of Golden eagles in three plots, i.e., line-thinning, control, and normal foraging habitat plots. In the line-thinning plot, the number of hare pellets, which was used as an indicator of the number of individual hares, increased remarkably the year after line-thinning, although the number decreased in the second year after line-thinning, and finally ended up being similar to that before line-thinning. Snakes were rarely observed in any plot. The foraging activity of Golden eagles in the line-thinning plot was lower than in the normal foraging habitat plot throughout the study period. Therefore, unfortunately, the line-thinning practiced in this study was not effective for increasing the foraging activity of Golden eagles, although this trial was successful in causing a temporary increase in the prey animals. Therefore, it is necessary to devise a method for making foraging habitat as quickly as possible, while promoting practical forest management, in order that Golden eagles may continue to exist in this area.

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We propose the Adaptive Management model for Uncertain Strike Estimates for birds (AMUSE). Between February 2004 and January 2007, seven dead white-tailed sea eagles were found near wind turbines in Hokkaido prefecture, Japan. We used this population as the target species in the management model. In the management model, we assumed that the bodies of any birds killed in collisions would disappear within 5 days, while the searches for carcasses were conducted every 30 days. The calculation period of the management model was 22 years, consisting of a 5-year planning period and a 17-year operation period. The operation management schedule was reviewed every three years. The utilized capacity was estimated from the data for 2003 to 2005 for Hokkaido. The operation rate multiplied by the utilized capacity gives the corrected utilized capacity. After the break-even point of the utilized capacity was determined, the time that fell below this was defined as the failure rate of the business. The results showed that the end point was achieved 99% of the time, while the failure rate was below 10%. An optimistic scenario was not affected by the two management scenarios or conditions used as protection measures. Conversely, a pessimistic scenario was achieved only under specific conditions in the management scenario. The main goals were to 1) estimate the number of days required for a carcass to disappear, 2) develop a search technique to improve the discovery rate of carcasses, 3) conduct regular surveys of carcasses, 4) determine the growth rate and population size by monitoring, 5) determine the results of breeding by breeding pairs in Hokkaido, and 6) examine risk hedging to deal with failure of the business.

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Ligustrum lucidum, originally from China, was planted as a roadside tree and has now naturalized and spread into Japanese urban areas. L. lucidum seedlings are frequently seen in urban areas and may create colonies. Therefore, the ecological characteristics of L. lucidum, such as seed dispersal, germination, and seedling survival rates, were compared with those of native L. japonicum. In comparison with L. japonicum, L. lucidum produces many small fruit (fruit length 6.55±0.68mm, fruit diameter 5.53±0.55mm), and numerous birds were observed eating the fruit (205 individuals/22.5 hours). The results suggest that birds disperse many seeds of L. lucidum. L. lucidum germinated under shady conditions, but the seedling survival rate in a forest was significantly lower than at the forest edge. The frequency of presence increased with the amount of light. The logistic curve showed that the frequency of presence reached 50% when the relative photosynthetic photon flux density (RPPFD) exceeded 6.3%. Light also affected the size of L. lucidum saplings. This suggests that L. lucidum is a light-requiring species, for which establishment is difficult and mortality is high under shady conditions. Under bright conditions, it can establish and grow well, and will probably spread further in the future.

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We examined the response to the aboveground removal of a noxious invasive plant Rudbeckia laciniata L. (Compositae), conducted in June. The belowground size and proportion of flowering individuals were compared in a plot subject to aboveground removal and in an undisturbed plot in Hakone, Central Japan. The relationship between the number of flowers and belowground size was examined in another undisturbed plot. Although aboveground removal significantly suppressed the flowering rate, the R. laciniata in the aboveground removal plot had a larger belowground size than in the undisturbed plot. The number of flowers increased with the belowground size in the undisturbed plot. Our result indicates that annual aboveground removal conducted in June is not efficient for eliminating R. laciniata; indeed, it may induce mass flowering and seed production when the aboveground removal ceases.

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It is necessary to monitor the distribution of an invasive species, the small Indian mongoose, Herpestes javanicus, on Amami-Ohshima Island in order to eradicate them effectively. To assess this distribution, tracking-tunnels were placed on the forest floor at points along four forest roads in the summer of 2006 and winter of 2007. Mongoose foot prints were seen in 94 of 557 (16.9%) tracking-tunnels in the summer and in 78 of 347 (22.5%) tracking-tunnels in the winter. Within a 14-km radius of the original release point of the mongoose along the Amami Central Forest Road (ACF-Road), the percentage was as high as 41.4%, although mongooses are trapped continuously in this area. This high percentage is probably because they are trap shy, and their density may have remained unchanged. We observed signs of invasion at points more than 30km from the original release point along the ACF-Road, and in the northern part of Amami-Ohshima Island. As part of the process of eradicating the mongoose, tracking-tunnels are a very useful tool for monitoring surveys.

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The Ocean Biogeographic Information System (OBIS) has developed an international portal site that allows users to access and use marine species occurrence information online, through a web browser. A mirror site in Japan for the international OBIS portal is available at the National Institute for Environmental Studies. The mirror site includes over 11,000,000 records and 70,000 species from 163 distributed databases (as of December 2006). The coverage of records along the coast of Japan is limited to invasive marine species, although large numbers of species occurrence records from around Japan have already been registered in OBIS, in other parts of the world. The geo-referenced species occurrence and time line information in the OBIS database is considered to be a complementary tool, to be used with the Global Invasive Species Database (GISD) beta version, for analyzing the historical invasion and habitat extension of known alien species. The occurrence information for 29 marine species that have been identified as invasive alien species in the GISD can be retrieved from OBIS. The mapping of these records along a time line revealed the history of invasion of Carcinus maenus, from the Atlantic to the southern Pacific Ocean. However, the occurrence of Carcinus maenus and other known alien species, such as Ciona intestinalis and Molgula manhattensis, around Japan cannot be confirmed with OBIS data, although these species have reportedly invaded Tokyo Bay and Osaka Bay. To close the information gap, it is necessary to obtain information from marine ecosystem monitoring projects from around Japan; this will help to increase public awareness of marine invasive species around Japan and faciliate further analysis of the interaction between environmental change and species distribution.

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Between May and July 2007, eight queens of Bombus terrestris, which has been introduced as an agricultural pollinator and naturalized over a large area of Hokkaido, Northern Japan, were observed or captured in the Notsuke Peninsula. This area is the most important range of a rare native species, B. florilegus. In early June, we spent 20 hours investigating flower visits by introduced and native bumblebees in the Notsuke Peninsula. A total of 217 queens from seven native species were observed, including six B. florilegus and one B. terrestris queen. Despite the lack of detailed information, B. florilegus, which belongs to the same subgenus Bombus, may have similar ecological characteristics to B. terrestris; such characteristics may include flower use and nesting habitat selection. Therefore, B. terrestris has the potential to negatively affect B. florilegus and is likely to displace it through competition. In addition, these two species have similar hair color patterns, with two yellow bands on the thorax and a white tail. Therefore, the introduced bees should be carefully suppressed in this area.

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