Yoshinobu Kusumoto

A macro-scale perspective on within-farm management: how climate and topography alter the effect of farming practices

Organic farming has the potential to reverse biodiversity loss in farmland and benefit agriculture by enhancing ecosystem services. Although the mixed success of organic farming in enhancing biodiversity has been attributed to differences in taxa and landscape context, no studies have focused on the effect of macro-scale factors such as climate and topography. This study provides the first assessment of the impact of macro-scale factors on the effectiveness of within-farm management on biodiversity, using spiders in Japan as an example. A multilevel modelling approach revealed that reducing pesticide applications increases spider abundance, particularly in areas with high precipitation, which were also associated with high potential spider abundance. Using the model we identified areas throughout Japan that can potentially benefit from organic farming. The alteration of local habitat-abundance relations by macro-scale factors could explain the reported low spatial generality in the effects of organic farming and patterns of habitat association.

Comparison of the Species Compositions between Past and Present Semi-Natural Miscanthus sinensis Grassland in the Kanto Plain

Semi-natural grassland maintained by traditional agricultural practices like mowing and burning has been widely decreased due to urban development and abandonment for more than 50 years, causing the loss of habitats of many native grassland species. In this study, we aimed to evaluate the vegetation of Miscanthus sinensis grassland currently remaining in the eastern part of the Kanto Plain by comparing it to the vegetation of the past extracted from data on regional flora compiled in the 1970s and 1980s. As a result, it became clear that the vegetation of the remaining Miscanthus sinensis grassland established on former arable or reclaimed lands was totally different from the species composition of past semi-natural grassland. Miscanthus sinensis grassland still maintained by agricultural practices remains on the steep slopes between uplands and lowlands where there are paddy fields located at the bottom of the narrow valley called ‘Yatsu’. This vegetation, however, was also significantly different to that of the past, lacking many native perennials selected as indicator species for past semi-natural grassland.

Potential roles of small and linear habitat fragments in satoyama landscapes for conservation of grassland plant species

By comparing with the historic semi-natural grassland and woodland vegetation data compiled in the 1970s and 1980s, we aimed to reveal potential roles of small and linear habitat fragments remaining in the urbanized satoyama landscape (i.e., agricultural landscape) in Japan for conservation of grassland plant species. TWINSPAN cluster analysis differentiated the current vegetation from historic one. Current vegetation of Miscanthus grassland was classified into two different groups and one of the two was equivalent to current understory vegetation of fragmented woodland. The linear woodland edge vegetation along the roads was classified into one group and separated from the other current vegetation groups. The current vegetation groups were characterized by higher richness of exotic species than historic vegetation groups. Detrended correspondence analysis (DCA) revealed that there were no groups of current vegetation that is equivalent to historic woodland understory vegetation. The vegetation quality of the current group of Miscanthus grassland and secondary woodland remaining on urban public properties, and the group of linear roadside vegetation were almost equivalent to that of historic semi-natural grassland. Both of the small and linear habitat fragments might have functioned as habitats for grassland species under regular mowing management. Although small and linear habitat fragments would not be sufficient for sustaining grassland populations in the future, these habitats can serve as key reservoirs for grassland species recovery in the conservation and restoration of grassland communities in the urbanized satoyama landscape.

Partitioning the plant diversity of semi-natural grasslands across Japan

Effective conservation of global species diversity requires a clear understanding of spatial scales that support overall diversity across broad scales. Abandonment of semi-natural grasslands has increased their fragmentation and decreased their areal extent. We quantified diversity patterns of plant communities in Japan across hierarchical scales to facilitate the development of an effective nationwide strategy for conserving species diversity in remnant semi-natural grasslands. We applied additive partitioning of plant species diversity, using a nested hierarchical design at three spatial scales (quadrat, grassland, and western and eastern regions of Japan) for three groups of plant species (all species, grassland species and national Red Listed species). We consistently found lower proportions of among-quadrats diversity, and higher proportions of among-grasslands diversity and between-regions diversity in the overall diversity of the entire species complement than would be expected by chance. The high contribution of among-grasslands diversity to overall diversity suggests that each grassland had a unique species content. The second-ranking contributor to overall diversity differed between grassland species and Red Listed species: the second-ranking contributor for grassland species was diversity at the among-quadrats scale but the second-ranking contributor for all species and for Red Listed species was diversity at the between-regions scale. Thus, effective conservation of diversity of the entire species complement in remnant semi-natural grasslands requires preservation of beta diversity in individual grasslands. Our findings highlight the importance of strengthening local preservation and restoration activities within each grassland, and of nationwide strategies for conserving Red Listed species in remnant semi-natural grassland communities.