This study examined the growth of aquatic animals in the canal system constituting the main, lateral, and farm drains in a consolidated paddy field, with emphasis on canal structure and year-round water flow in the canals. A field survey at six sites, which involved three different canal levels, was carried out in Chikusei, Ibaraki Prefecture, Japan (36゜21'N, 139゜59'E). Sampling was conducted at monthly intervals from April 2001 to March 2002. Of the freshwater fish, young-of-the-year (YOY) Zacco platypus appeared in September, while YOY Misgurnus anguillicaudatus appeared in May. Last instars of the damselfly Calopteryx atrata were collected only in June, suggesting emergence about this time, while those of the dragonfly Orthetrum albistylum speciosum were collected in May and July, suggesting a longer duration of emergence. Since populations of the four species decreased during the non-irrigation season when the water level was low, I propose that a marsh be developed as a wintering site in the lower reaches of the canal system in consolidated paddy fields.

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To evaluate the condition of populations of the threatened aquatic plant Nymphoides peltata in Japan, we investigated the vegetation area, composition of floral morphs (long-, short-, or homo-styled morphs), and genetic diversity using ten microsatellite loci for all known subpopulations. Sixty-four subpopulations were identified in 27 river systems. Only 1 of the 33 subpopulations where flowers were detected had both long- and short-styled morphs and a relatively high potential for sexual reproduction; it was located in Lake Kasumigaura. Using microsatellites, 61 genets were detected in the subpopulations. The genetic data suggest that each N. peltata subpopulation in Japan is at high risk of extinction because of the low genet diversity and low sexual productivity. The subpopulation that had both floral morphs consisted of ten genets, which suggests the importance of sexual reproduction to the preservation of genet diversity. In an amendment of the Japanese Red List in 2007, this species was reclassified from vulnerable to near-threatened. However, our study suggested that the species should be conserved as a vulnerable species.

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Riparian habitats are important for rare grassland butterflies. However, exotic plants have recently invaded these habitats, and have often spread rapidly and widely. Indigofera pseudotinctoria Matsum. is a shrub in the Leguminosae, and is the host plant of the threatened butterfly Lycaeides argyrognomon praeterinsularis. An exotic invasive grass, Eragrostis curvula (Schrad.) Nees, has recently populated the floodplains of the Abe River in Shizuoka, Japan, and its ecological impact on I. pseudotinctoria and therefore on L. argyrognomon is of increasing concern. We examined the occurrence of L. argyrognomon, the size of I. pseudotinctoria populations, and the invasion status of E. curvula at 32 sites along a river where L. argyrognomon had previously been recorded. Then, we conducted a three-year removal experiment at Kadoya to assess the effects of removal treatment on I. pseudotinctoria. Adult L. argyrognomon were observed at seven sites (21.9%) that were all located in the middle reach (21〜30km from the mouth) of the river. E. curvula was observed at 20 sites (62.5%), including five sites with L. argyrognomon. The removal experiment confirmed that this treatment has positive effects on both the flower and seed production of I. pseudotinctoria. In the third year of the experiment, the total number of flowers per plant was 6,965.5±2,308.9 (mean±SE) in the removal plot and 2,467.7±658.6 SE in the invaded one (i.e., the control). The total number of seeds per plant was 573.2±156.2 and 300.7±29.2, respectively. Contrary to our expectations, the recovery of seed production was rather small due to the extremely low fruit set (4.3±0.9 and 3.2±0.6, respectively). These findings suggest that special effort is needed to prevent E. curvula invasion of the existing L. argyrognomon habitat, and for restoring these sites properly to increase habitat quality. At the landscape level, designing and restoring the habitat networks connecting the current habitat (core sites) and Kadoya (the demonstration site) are necessary for the conservation of L. argyrognomon along the river.

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We examined the effect of rhizome removal on the invasive perennial Rudbeckia laciniata L. in a laboratory experiment and field observations in Hakone, Kanagawa prefecture, Japan. To evaluate regeneration, randomly cross-sectioned fragments of R. laciniata rhizomes were cultivated in the laboratory for 60 days (25℃/15℃, 12h/12h). The probability of above-ground regeneration increased with the weight of the cultivated rhizome. The number of culms was monitored for three years in 14 plots where all R. laciniata within the plots were removed annually. The number of flowering culms deceased drastically. Nevertheless, culms with no flowers, which were thought to have originated from the seed bank, were abundant in the third year. These results suggest that R. laciniata can be eradicated by continuous rhizome removal. Based on these findings, schemes for eradicating R. laciniata were discussed.

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Weed invasion of natural forests due to recent increases in their use as recreational sites poses a problem affecting forest preservation. This study examined the effects of passage for recreational activities on the occurrence of weeds in forests. Weeds were surveyed in disturbed and undisturbed areas along both roads and naturally formed walkways in a temperate secondary forest located at Ashiu Forest Station, Kyoto University. Weeds were generally observed in the disturbed areas, with the greatest amount and highest species number observed along the roads. Based on the life-form classification of the weeds, species that appeared to invade easily tolerated physical pressure and dissemination by humans, vehicles, and wind along roads but only dissemination by humans along walkways. Among the environmental factors considered, light intensity and soil moisture, which were negatively correlated with each other in the road area, differed significantly between road and walkway areas. For the road area, there tended to be fewer weed species with increasing relative light intensity. This unexpected tendency might be due to the greater open space in the areas with more light, where wind and drier conditions suppressed weed growth. There were more weed species on the road surface than on slopes adjacent to the roads, and more on the walkways than on the adjacent undisturbed areas, where there were no weeds. As these differences could not be explained by the difference in dissemination frequency, changes in soil characteristics resulting from the physical pressure of repeated trampling by people or from vehicle tires were thought to be involved.

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We investigated the species composition and structure of plantation forest understory with and without slope protection, with particular focus on the establishment of terrestrial pteridophytes. Both pteridophyte coverage and the number of pteridophyte species were higher in the understory with slope protection than in that without slope protection. The frequency of occurrence of several pteridophyte species was also higher with slope protection. Furthermore, the number of pteridophyte species per unit area was considerably higher in understory with slope protection than in that of neighboring secondary forests. Pteridophyte species included not only plants growing in open, sunny sites but also those growing in the forest interior. In contrast to pteridophytes, the species composition and structure of seed plants did not markedly differ between understory with slope protection and that without slope protection. Both types of understory contained high abundances of several species of greening/garden trees, alien tree species, and high-light herbaceous plants. These results suggest that forest understory with slope protection serves as suitable habitat for many pteridophytes, even in areas with edge effects. The potential factors promoting the establishment of pteridophytes in protected-slope understory include the improvement of soil water maintenance and the stair-like slopes formed as part of the protective function.

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Past relative changes in populations of three Xanthium species (X. italicum Moretti, X. strumarium L., and X. occidentale Bertol) in the northern Kinki District were investigated based on herbarium specimens. Populations of X. strumarium rapidly decreased in the 1950s and 1960s, leading to its extinction, while X. occidentale became dominant after 1950. Xanthium italicum rapidly increased in the 1980s, through invasion starting from Osaka Bay and extending inland along rivers. Herbarium specimens appear effective for the analysis of past relative changes among allied species.

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The genetic diversity and differentiation among 60 individuals of the threatened dragonfly species Libellula angelina from three populations in the Okegayanuma area of Japan was determined using random amplified polymorphic DNA (RAPD) analysis. Twenty polymorphic loci were detected by 19 of the 80 RAPD primers examined, and 12 DNA types were determined (only four types were population specific). The diversity among and within the populations was lower; the mean gene diversity and gene differentiation values were 0.317 and 0.007, respectively. No significant between-population genetic differences were detected in the analysis of molecular variance (AMOVA). Of the genetic divergence, 98.7% was attributable to population divergence and 1.3% to individual differences within a population. Cluster analysis indicated that most individuals from the three populations belonged to the same cluster. Our results provide data that could be used to elucidate genetic diversity in L. angelina populations, using RAPD analysis.

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The presence and origin of plants listed in the Red Data Book (RDB) were examined in 240 home gardens in each of four villages in Nagasaki, Wakayama and Shizuoka Prefectures of Southwestern Japan in order to address three changes in biodiversity caused by the collection and relocation of plants mainly for ornamental use. Fifty-three RDB plant species belonging to 25 families were recognized, and more than one RDB species was maintained in 82% of the home gardens examined. Interviews of the inhabitants indicated that the primary origin of the RDB plants in the home gardens was collection from their original habitat (89 cases), followed by gifts from relatives or friends (45 cases), and purchase at gardening shops (12 cases). Species richness and the degree of diversity of the RDB plants present in a village were high in the mountainous villages engaging in agro-forestry and low in the seaside villages engaging in fishery. The escape from cultivation of RDB plants in home gardens and the intercrossing of inbred cultivars of RDB species with their natural populations may cause genetic contamination.

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Primula kisoana Miq. var. kisoana is a heterostylous clonal herb that grows only in the vicinity of Mt. Narukami in the southern part of Gunma Prefecture, Japan. Recently, its populations have declined severely due to habitat loss and intensive horticultural exploitation. Extremely low seed set has also been observed as a possible consequence of the wide geographical dispersion of compatible genets. To assist in the reproduction of the species from flowering to new genet establishment, we proposed a program comprising (1) artificial hand pollination, (2) seed germination treatment, and (3) ex situ cultivation and reintroduction of seedlings, and assessed its efficacy and feasibility in combination with the collaboration of local residents. Legitimate (intermorph) crosses between flowering ramets resulted in enhanced seed set. Seed dormancy could be broken by repetitive moist-chilling and subsequent temperature changes. The introduction of seedlings to potentially suitable habitats resulted in the survival of 15〜100% of individuals to the next year. These findings strongly suggest that our program is an efficient countermeasure for sexual reproduction failure and is effective for restoring long-lasting, self-sustainable populations of P. kisoana var. kisoana.

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Action to conserve the endangered species Aster kantoensis along the middle reaches of the Tama River, which runs through southwestern Tokyo, through a partnership involving citizens, public administration, and researchers started in 2002 (called the 'Aster Project'). The project was renewed in April 2007 because of an expanded scale of activities. After finishing all activities in 2007, we evaluated the new system through an oral survey of those citizens who had participated in the project from its commencement, in 2002. The new system was thought to have a positive image. It was easy to participate in the project because a newsletter had been sent out. However, the new system retained an important organizational problem: the relationships between citizens, public administration, and researchers were insufficient for the ideal operation of the system. It is difficult to remove a key factor causing the decrease in Aster kantoensis biomass because social problems, such as changes in river management, still need to be solved. However, it is important that this problem is resolved in order to achieve an ideal status for the Tama River. Agreements between public administration and researchers alone are insufficient. Understanding and agreements based on the experiences of citizens in watershed areas are indispensable. Conservation actions such as the 'Aster Project', involving partnerships between citizens, public administration, and researchers, are important for solving this big problem.

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Conservation measures have been implemented in Lake Kasumigaura, Japan, to restore the population of an endangered floating-leaf plant, Nymphoides peltata, from the seed bank remaining in lakeshore soil. Adaptive management was undertaken to elucidate the life history of this plant and restore the restricted environmental conditions needed for seedling establishment and subsequent vegetative growth. First, the lakeshore topography was rehabilitated using civil engineering techniques to create the hypothesized condition of "safe sites" for seedling establishment, i.e., bare ground exposed during lower water levels in spring. This led to the successful establishment of 267 seedlings in 2002. However, these seedlings retained their terrestrial form instead of adopting the floating-leaf form. As the next steps, the established seedlings were cultivated under shallow water and then reintroduced into the lake in 2004. Vegetative growth occurred and was followed by flowering, seeding, and emergence of new seedlings. By 2007, a population consisting of at least ten genets had been restored in a 488m^2 area. This study reveals that recovering the original water regime of the lake through spring drawdown and subsequent raising of the water level is essential to restore a self-sustainable population of N. peltata.

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The aim of this study was to evaluate the comparative importance of habitat types for the conservation of biodiversity. We determined the number of endangered vascular plant species for each habitat type using the regional Red Data Book that contains information for five prefectures in the Chugoku region, western Japan, together with data on the area covered by each habitat type obtained from the fifth national vegetation survey. The habitat types were classified as "forest", "agricultural field," "wetland," "rocky ground," "grassland," or "seaside." Although many of the listed endangered species belonged to forest habitats, at the regional level, the species/area ratios were higher in the grassland, wetland, and seaside habitats than in the forest and agricultural field habitats. However, the conservation priorities for the endangered plant species in relation to habitat type showed only a slight variation among the prefectures examined.

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Echinops setifer is an endangered perennial herb found in semi-natural grassland in the Tokai, Chugoku, and Kyushu regions of Japan. To elucidate the status of E. setifer populations on Aso Mountain and Chugoku Mountain regions, we conducted field surveys and genetic analysis using microsatellite markers for all known populations in these two regions. Field surveys revealed the existence of only several tens of mature individuals in each population and a decrease in the number of mature individuals in most populations. Analysis of genetic diversity showed that the diversity of the remnant population was relatively low on Aso Mountain. In nearly half of all cases, the vegetation in E. setifer habitats has dramatically changed due to a change in, or abandonment of, traditional grassland management systems in recent decades. The change in grassland vegetation threatens the continued existence of E. setifer individuals. Thus, maintenance and monitoring of vegetation in the habitats of this plant are essential for E. setifer conservation programs.

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Recently, local governments in Japan have published Red Data Books as a baseline for regional biodiversity management. However, these books often lack explicit criteria for selecting endangered species and the detailed information required for implementation of effective conservation programs. Considering these problems, we compiled a Red Data Book of endangered vascular plant species for Ushiku City, Ibaraki Prefecture, based on an objective approach. We also tried to infer practical measures required for conservation of each species described in the new book.

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