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DOI： 10.1007/s12224-022-09408-z

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Language：English   Publishing type：Research paper (scientific journal)  

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DOI： 10.1080/13416979.2020.1742857

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Language：English   Publishing type：Research paper (scientific journal)  

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DOI： 10.1186/s13002-019-0301-8

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DOI： 10.1093/jpe/rty024

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER JAPAN KK  

The European honeybee, Apis mellifera L. (Hymenoptera: Apidae), is the most important crop pollinator, and there is an urgent need for a sustained supply of honeybee colonies. Understanding the availability of pollen resources around apiaries throughout the brood-rearing season is crucial to increasing the number of colonies. However, detailed information on the floral resources used by honeybees is limited due to a scarcity of efficient methods for identifying pollen species composition. Therefore, we developed a DNA barcoding method for identifying the species of each pollen pellet and for quantifying the species composition by summing the weights of the pellets for each species. To establish the molecular biological protocol, we analyzed 1008 pellets collected between late July and early September 2016 from five hives placed in a forest/agricultural landscape of Hokkaido, northern Japan. Pollen was classified into 31 plant taxa, of which 29 were identified with satisfactory discrimination (25 species and 4 genera) using trnL-trnF and ITS2 as DNA barcoding regions together with available floral and phenological information. The remaining two taxa were classified to the species level using other DNA barcoding regions. Of the 1008 pollen pellets tested, 1005 (99.7%) were successfully identified. As an example of the use of this method, we demonstrated the change in species composition of pollen pellets collected each week for 9 weeks from the same hive.

DOI： 10.1007/s13355-018-0565-9

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NORTHEAST FORESTRY UNIV  

Natural forest recovery on abandoned farmland is hindered by a variety of factors and active restoration plays an important role when quick afforestation is desired. We investigated seedling survival of four transplanted native tree species (Quercus myrsinifolia, Quercus serrata, Aphananthe aspera, and Rhus sylvestris) by experimentally manipulating the vegetation cover, which was mainly dominated by dwarf bamboo (Pleioblastus chino), and herbivore access to the planting sites on farmland that had been abandoned for 15 years at the start of the study. Few transplanted seedlings of any species survived under intact vegetation cover, irrespective of herbivore presence. In gaps in the vegetation cover, winter browsing by Japanese hare (Lepus brachyurus) damaged all species. However, lower browsing frequency and higher resprouting ability after grazing of the seedlings enabled both Quercus species to survive better than the other species. These results indicate that dwarf bamboo and the hare jointly limit the establishment of native trees in old fields. If active afforestation by transplanting seedlings at sites dominated by dwarf bamboo is planned, a combination of vegetation removal, selection of suitable species, and temporary seedling protection will be most effective.

DOI： 10.1007/s11676-016-0257-7

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J-GLOBAL

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：THE JAPANESE FORESTRY SOCIETY  

<p>Many plants carried by human migration and trade have become naturalized and significantly affected local ecosystems. A deciduous tree, <i>Firmiana simplex</i> (Malvaceae), of uncertain origin, grows in warm temperate regions in Japan. We explored anthropogenic influences on the distribution of <i>F. simplex</i> along the coast of the Bungo Channel, eastern Japan, by evaluating the successional sere that the species occupies, historical usage, and local plant names. An old land use map, historical records, local knowledge, and field observations of forest stands indicated that the <i>F. simplex</i>-dominated forest on Kashima, Ainan town, Ehime Prefecture, which was generally perceived as primary forest, was most likely anthropogenically disturbed. The <i>F. simplex</i> in several other localities had an aggregated distribution and grew at disturbed sites. These results imply that the species favors mid-successional forest stands. Trunk fiber had various uses around the mid-20th century in the study region. Interviewees told of planting this species on backyard slopes in Kochi Prefecture, and on mountain slopes in Miyazaki Prefecture. Common local names <i>hera</i> and <i>isaki</i> were recorded in both Kyushu and Shikoku. According to a historical record, <i>Tilia</i> species (Malvaceae), which are also called <i>hera</i>, were brought to the Chugoku region for trunk fiber usage in the early 19th century. This fact and our results suggest that <i>F. simplex</i> was introduced along the coast through the cultural diffusion of fiber usage and is now concentrated around specific villages.</p>

DOI： 10.4005/jjfs.98.199

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Other Link： https://agriknowledge.affrc.go.jp/RN/2010903428

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NORTHEAST FORESTRY UNIV  

Restoring natural forests after field abandonment is a land management objective that fosters the recovery of forest biodiversity. We performed seeding and transplanting of native tree species 40 years after the abandonment of an arable field that became dominated by a dwarf bamboo (Pleioblastus chino (Franch. et Sav.) Makino) and by kudzu (Pueraria lobata (Willd.) Ohwi). By permutation tests, the removal of competing vegetation (gap creation) significantly increased the survival of three seeded species of Fagaceae and of eight transplanted species. In contrast, intact vegetation prevented most individuals of all species from surviving for 1 year after planting. The lack of natural recruitment of Fagaceae in the nonseeded subplots indicated that seed limitation was a cause of the slow afforestation. Although litter accumulation in gaps at the time of seeding slightly increased survival for late-germinating Quercus myrsinifolia Blume and Castanopsis sieboldii (Makino) Hatus. ex T. Yamaz. et Mashiba, the effect was not consistent among plots and was not statistically significant. Our results suggest that for successful afforestation using native trees in abandoned fields, it will be necessary to remove competitive native species to avoid severe limitations on microsite availability and that simultaneous tree establishment by seeding or transplanting should be implemented to accelerate the establishment of native tree species.

DOI： 10.1007/s11676-015-0072-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER JAPAN KK  

Abandonment of traditional land uses has become an ecosystem management concern in many agricultural landscapes. In this study, we investigated the reforested vegetation about half a century after the abandonment of mountain slopes used for terraced fields and wood production on the Yura Peninsula, Ehime Prefecture, southwestern Japan. Multivariate analyses of species composition indicated that, although many endozoochorous evergreen trees were common on the mountain slopes, fern species adapted to inhabiting the stone-wall structures (e.g., Cyrtomium falcatum, Microlepia strigosa, and Asplenium incisum) and common weed species of arable land occurred significantly more frequently in former stone-walled terraced fields than in former unwalled terraced fields and secondary forests. Tree layer composition was influenced by the forest area around the abandoned terraced fields. Moreover, historically less disturbed forests in the southwestern part of the peninsula were core habitats for regionally rare species, such as Jasminanthes mucronata, Firmiana simplex, and Ardisia sieboldii, and some of those species became established within neighboring abandoned terraced fields. These results indicate that land-use legacies, especially stone-walled terracing and historical forest disturbances, influence the revegetation processes of abandoned mountain slopes in warm-temperate coastal areas.

DOI： 10.1007/s10310-014-0471-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

The cowpea aphid Aphis craccivora that infests the black locust Robinia pseudoacacia shows toxicity to its predator, the multicolored Asian ladybird beetle, Harmonia axyridis. In contrast, the same aphid species that infests the common vetch, Vicia angustifolia, is suitable prey for H. axyridis larvae. Previously, it was reported that the toxicity of A. craccivora infesting R. pseudoacacia was due to canavanine and 2-aminoethanol, but there was some doubt about the toxicity of these compounds and their concentrations in the aphids. In the present study, we determined the concentrations of cyanamide, canavanine, and 2-aminoethanol in A. craccivora infesting the two host plants. In the extracts of A. craccivora that infested either of the host plants, canavanine was undetectable, and 2-aminoethanol was detected at the concentration of 3.0-4.0 mu g/g fresh weight. Cyanamide was detected in the extract of A. craccivora that infested R. pseudoacacia (7.7 mu g/g fresh weight) but not in that infesting V. angustifolia. The toxicity of canavanine, 2-aminoethanol, and cyanamide was evaluated against H. axyridis larvae in a bioassay by using an artificial diet containing these compounds at various concentrations. Cyanamide exhibited 10-100 times stronger toxicity than canavanine and 2-aminoethanol. These results indicate that the toxicity is at least partly due to cyanamide, which is present in the toxic A. craccivora that infests R. pseudoacacia but absent from the non-toxic A. craccivora that infests V. angustifolia.

DOI： 10.1007/s10886-012-0220-9

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER INTERNATIONAL PUBLISHING AG  

Although noncrop woody plants in crop field landscapes serve multiple functions, the modernization of agriculture has threatened their preservation. In this study, isolated woody plants used as farmland boundary markers were investigated in Ibaraki Prefecture in the eastern Kanto region. A total of 2001 individuals of 50 species were found around 177 equidistantly spaced points. The most frequently used species was Deutzia crenata (60.7%), and the main subordinate species were Pourthiaea villosa (8.8%), Euonymus japonicus (7.7%), Camellia sinensis (6.8%), Morus bombycis (4.6%), and Celtis sinensis (4.2%). According to multiple kernel density estimation, all six species were estimated to have at least one core area of high presence probability. Spatial segregation analysis of those species observed more than twice indicated that the marker usage showed significant spatial heterogeneity in the region. According to managers at 32 farms, marker plants are seldom used for other purposes. Trimming frequency of markers varied among the managers, even for the same species. Most of the managers did not know the introducer, introduction year, and marker plant source, except four managers who introduced or restored the markers using D. crenata (n = 2) and E. japonicus (n = 2). These findings suggest that the regional diversity of markers reflects historic species selection. Therefore, preservation of woody plant markers must be planned based on the local characteristics of biocultural resource usage.

DOI： 10.1186/2193-1801-1-57

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Field abandonment has increased over several decades under a long-term recession in Japanese agriculture. To support effective farmland management or reforestation, the patterns of tree recruitment in abandoned fields, which influence management costs, need to be clarified. We investigated tree seedling establishment and microsite variables along forest-field transects in 11 abandoned fields adjacent to secondary broad-leaved forests in the eastern Kanto region of Japan. Generalized linear mixed model analysis indicated that tree seedling establishment in abandoned fields was not correlated with the period of abandonment. Instead, it was positively correlated with vegetation openness. The dominance of a woody vine (Pueraria lobata), an annual liana (Humulus japonicus), and a dwarf bamboo (Pleioblastus chino) mainly explained low vegetation openness within the fields. In addition, the establishment of evergreen tree seedlings and tree seedlings dispersed by hoarding was negatively correlated with the distance from the forest edge. In the forest interior, taller understory vegetation at the edge correlated with lower seedling establishment. These results suggest that seedling establishment across forest-field ecotones is restricted by the dominance of competitive natives within abandoned fields and distance-dependent limitations in both abandoned fields and adjacent forest.

DOI： 10.1007/s11258-010-9868-9

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

The ladybird beetle Harmonia axyridis is an aphidophagous natural enemy in Japan. The alien plant Solidago canadensis is widespread in Japanese agricultural landscapes, and the alien aphid Uroleucon nigrotuberculatum parasitizes the plant. We examined the quality of the aphid as food for all developmental stages of H. axyridis. First-instar larvae fed the aphid died within 2 days. Larvae at later developmental stages survived for significantly longer periods but died before pupation. Adults fed the aphid also died within 10 days. These results suggest that U. nigrotuberculatum parasitizing S. canadensis is unsuitable for H. axyridis during the beetle&apos;s entire life cycle.

DOI： 10.1007/s11284-011-0803-x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL PUBLISHING, INC  

P&gt;Paddy field agroecosystems are floristically highly diverse, but the mechanisms affecting this diversity are not clear, especially at broad spatial scales. To conserve paddy weed species, we aimed to clarify the importance of landscape-scale variables for in-field floristic diversity. Statistical evidence of the shape of the species response along environmental gradients was obtained by Detrended Correspondence Analysis, DCA. Predicted variables were landform type (narrow valley floor, wide valley floor, old river channel, meander plain with dry soil and meander plain with wet soil), intensity of land improvement (six classes) and species attribute. Both landform type and land improvement intensity were important in explaining variations in in-field floristic diversity. Non-paddy weeds and rare threatened species occurred frequently in unimproved plots. Plots in the narrow valley floor and old river channel landform categories had representative species that were categorised as threatened. Unimproved plots also had representative species that were categorised as threatened. The threatened representative species in unimproved plots were confined to old river channels. Unimproved plots in old river channels were the most vulnerable in terms of conservation. Estimation of floristic patterns in paddy fields using landform type and land improvement intensity could be a useful tool for maintaining floristic diversity.

DOI： 10.1111/j.1365-3180.2010.00815.x

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DOI： 10.2750/arp.30.249

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

Although the value of noncrop vegetation for biological control has been extensively studied in agricultural landscapes, there are few reports on how it functions mechanistically. When focusing on the pest control function provided by noncrop vegetation, tritrophic interactions among a predatory natural enemy, its prey, and the prey&apos;s host plant need to be examined. In Japan, the multicolored Asian ladybird beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), an aphidophage, serves as a natural pest control agent in agricultural production, although the species&apos; introduction into Europe and North America for pest control has had a negative impact on native ecosystems. In the present study, 33 aphid-plant pairs from an agricultural landscape in the eastern Kanto region of Japan were examined experimentally for initial larval survivorship and development of H. axyridis. Significant differences were found among plant-aphid pairs with regard to these parameters. In addition, the larval survivorship of H. axyridis was not consistently determined by host plant or aphid species alone but was context-dependently influenced by the aphid-plant combination. Some alien host plants showed positive effects on the ladybird beetle. Others, however, served as hosts for unsuitable prey species, such as the competitive alien plants Solidago canadensis L. and Robinia pseudoacacia L., which are the host plants of Uroleucon nigrotuberculatum (Olive) and Aphis craccivora Koch, respectively. These findings suggest that various noncrop plants could be managed to promote ladybird beetle populations in rural landscapes.

DOI： 10.1007/s11284-010-0739-6

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DOI： 10.2750/arp.27.347

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Agricultural landscapes with spatial and temporal variations interact with each other to affect the existing biodiversity. Though rice fields provide important habitats for birds all over the world, studies so far have rarely explored the effects of landscape heterogeneity on bird species in rice paddy areas. This study investigated the effects of habitat cover and landscape variables on the species richness and the abundance of birds in rice paddy areas in Japan. Data on bird occurrence and the environment were collected at 32 grid squares (1 x 1 km) in the Tone River basin. The richness and the abundance of agricultural wetland species were particularly high in landscapes with large areas of rice fields in summer, when rice fields were irrigated, but in those with large areas of open water in winter, when rice fields were drained. It is important to maintain a combination of rice fields and open water to satisfy multiple habitat requirements by agricultural wetland species throughout the year. Grassland species were positively associated with a rich diversity of land cover including fallow fields and open water, indicating the importance of a simultaneous existence of multiple landscape elements. Forest cover in landscapes positively affected edge species and woodland species. Since forest cover had a relatively strong correlation with edge density, the responses of bird species to changes in forest cover and edge density need to be explored further. This study illustrates the importance of spatial and temporal landscape complementation for bird species in rice paddy areas. (c) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.biocon.2008.04.012

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DOI： 10.2750/arp.26.227

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Language：Japanese  

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