River gravel floodplains are important habitats for plants which grow in dry and periodically disturbed environments. However, as the result of human impacts, most of those floodplains are covered with thick sandy deposits which allow dominance of tall-growing perennial grasses, such as Miscanthus sacchariflorus and M. sinensis. Prescribed field burning is considered to be one of the effective methods to manage the floodplain vegetation dominated by tall grasses. We aim to clarify the effects of the field burning on the flora of the floodplain covered by dense Miscanthus species. The research was conducted in the Houki River, Tochigi Prefecture, where floodplain vegetation has been burnt at the end of February every year by local people. Between 36 burnt stands and 14 unburnt stands, there was a clear floristic difference in both M. sacchariflorus and M. sinensis communities. Jaccard's coefficients between the burnt and unburnt stands were lower than 0.5, showing that field burning changed the floristic composition drastically. In addition, field burning increased the number of native plants per area without increase of alien plants. Twenty eight species including endangered species were recorded with a higher frequency in the burnt stands than in the unburnt stands, for both M. sacchariflorus and M. sinensis communities. Especially, the occurrence of spring ephemerals was unique in M. sacchariflorus community. On the other hand, 7 and 14 species occurred with a higher frequency in the unburnt stands for M. sacchariflorus community and M. sinensis community, respectively. Furthermore, field burning showed a positive effect on plants which possess particular traits; Geophytes and herbs which flower in early spring were more prominently represented in the burnt stands. The major reason for the floristic differences can be litter removal which interrupts sunlight and prohibits shoot emergence. On the other hand, field burning showed a negative effect on winter annuals which suffer from fire directly. Although the floristic composition after burning appeared to be quite different from original flora of river gravel floodplains, it may still include many species of conservation value. In addition, field burning did not induce alien species invasions. From these results we concluded that prescribed burning is the effective tool for the vegetation management in river floodplains under the artificially modified environment.

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Seedling populations from sea-borne seeds found on the coastal drift lines were studied in the context of sea current dispersal. The studies were done in northern and western Kyushu, Japan, where drift debris carried by the Tsushima Warm-current frequently washes ashore. Two thousand twelve seedlings comprising 47 species were found at 126 sites on 35 beaches in 10 regions. Not only maritime species, but also several inland species were commonly found. The most frequent seedlings was Tetragonia tetragonoides followed by Salsola komarovii. These two species comprised the drift plant communities. Most maritime species have sea-current dispersal seeds. Some inland herbaceous species such as Rumex japonicus and Polygonum senticosum of which seedlings were frequently found, also commonly grow on shingle beaches. Some inland woody species such as Cinnamomum camphora and Melia azedarach of which seedlings were also frequently observed, can not usually establish on beaches, but have a potential of sea-dispersal ability. Seedlings of tropical and subtropical plants such as Ipomoea pes-caprae and I. fimbrisepala were found far away from their propagation areas.

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For reducing the labor cost involved in vegetation mapping, we attempted to identify the forest types in forest areas by using high-resolution IKONOS satellite data. Thus we conducted a vegetation survey of 96 plots in Satoyama forest area and classified the plots into 8 forest types on the basis of the dominant tree species in the canopy layer. Cryptomeria japonica, Pinus spp., Castanopsis sieboldii, Quercus myrsinfolia, Q. serrata, Mallotusjaponicus, Phyllostachys bambusoides, and Phyllostachys heterocycla were detected as the dominant species representing the 8 forest types. The size of a plot was 16 m × 16 m and corresponded to 16 pixels of the IKONOS data. We developed classification tree models for each forest type by using 5 explanatory variables as follows: Normalized Difference Vegetation Index (NDVI), mean of the red band, standard deviations of the near-infrared band, red band and green band. Each model showed a good performance (area underthe curve, [AUC] > 0.8), except that by M. japonicus type. Each model involved a characteristic combination of the explanatory variables. The standard deviations of the near-infrared band and red band were adopted as the explanatory variables in some models such as that for Phyllostachys bambusoides type. Thus, textural property was also shown as useful for the identification of forest types when using the high-resolution satellite data; 72% of the plots were identified correctly. This result indicates that high-resolution satellite data could be used for mapping the Satoyama forest area.

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Distribution of wild boars, Sus scrofa Linnaeus, has drastically expanded in the last decade, and agricultural damages ensuing this expansion has been a serious problem in rural areas with mixed forest and fields, which represents Japan's cultural landscapes (Satoyama). Because agricultural activity in these areas has an important role in maintaining high biodiversity, solving the human-wildlife conflict in Satoyama areas remains a practical issue for the farmers and wildlife managers, but is also important for the ecosystem management of these culturally valuable landscapes. We carried out this study at southwestern part of Tochigi Prefecture, central Japan. Total of 86 releves were sampled in abandoned fields of the study area. We classified plant communities in the abandoned fields, and created 1/2500 land cover map reflecting the classification of plant communities. To investigate relationships between the distribution of wild boars and habitat types, we surveyed field sign of wild boars in November, February, May and August of 2010-2011. Six types of plant community were classified as follows: Digitaria ciliaris-Eleusine indica community (C1a), Setaria faberi-Erigeron philadelphicus community (C1b), Echinochloa crus-galli-Arthraxon hispidus community (C2), Artemisia indica var. maximowiczii-Potentilla hebiichigo community (C3a), Miscanthus sinensis-Solidago altissima community (C3b) and Pleioblastus chino community (C4). The feeding sign of wild boars tend to be found in the community types, C3a, C3b, and C4, throughout a year. In November and February, the feeding sign also tended to occur in the community types, C1a, C1b, garden and orchard. In May and August, it tended to occur in bamboo groves, and riverside. The resting sign tended to be found in the community types, C3b and C4, in August. Among the plant communities in abandoned fields, the management of the community types, C3b and C4, were important to reduce agricultural damages from wild boars in Satoyama landscapes.

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We examined the following three types of semi-natural grasslands established on the levee slopes of paddy fields in Northern Hyogo Prefecture, Japan: (1) traditional grassland (TG), i.e., grasslands managed on traditional paddy fields (paddy terraces); (2) abandoned traditional grassland (AG); and (3) non-traditional grassland (NTG), i.e., grasslands restored after consolidation of paddy terraces. In this study, the vegetation structure, dominant species, species composition, and species richness were compared among the three grassland types. Vegetation height was much higher in AG than in TG and NTG. The dominant species was Imperata cylindrica var. koenigii in TG and NTG, and Miscanthus sinensis in AG. The species composition of TG clearly differed from that of the other two types: many species found in TG were absent or rare in both AG and NTG. The number of native plant species per plot was the highest in TG, followed by NTG and AG. Species richness of alien plants was very low in not only TG but also NTG. Recovery of species composition and species richness after paddy consolidation tended to be faster for annual herbs than for perennial herbs. To examine the soil seed bank of AG, we conducted germination tests for soil samples taken from AG using the seedling emergence method. Of the 48 species found in TG, but absent or rare in AG, 17 species germinated from seeds buried in the soil of AG. This result suggests that the soil seed bank of AG could not play a significant role in the restoration of TG.

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We examined the effects of cutting and agricultural land reclamation on species diversity, species composition, and cover of pteridophytes. For this purpose, we compared natural evergreen broad-leaved forests with secondary deciduous broad-leaved forests established on post-agricultural sites in south Yunnan, China. The results showed that pteridophyte species diversity in secondary forests was similar to that in natural forests even considering the ecological traits of pteridophytes. Meanwhile, there remained slight differences in pteridophyte species composition: secondary forests were characterized mainly by the persistence of non-forest terrestrial species, whereas natural forests were characterized by the luxuriance of forest epiphytic species. In addition, the cover of non-forest terrestrial species was higher in secondary forests, whereas the covers of forest terrestrial species and forest epiphytic species were higher in natural forests. These findings suggest that although the study sites have a high potential for facilitating pteridophyte re-establishment, expansion of human interference should be avoided for ensuring the conservation of pteridophytes.

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