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Bamboos have expanded their distribution in Japan in recent decades due to the abandonment of forest management practices following depopulation and aging in rural communities. Developing effective uses for bamboo biomass resources is highly desirable. In this study, we tested the effectiveness of ground bamboo as a new organic mulching material for agrochemical-free rice farming. Specifically, we tested whether ground culms and leaves with or without refrigeration/fermentation treatments influenced rice production differently. Using plastic tubs (0.31 m2), we conducted a field experiment comprising five treatments with five replicates deployed in a randomized block design: (1) control, (2) fermented ground bamboo culm application, (3) refrigerated ground bamboo culm application, (4) fermented ground bamboo leaf application and (5) refrigerated ground bamboo leaf application. Ground bamboo application successfully suppressed the coverage of the most dominant aquatic weed, Monochoria vaginalis (Pontederiaceae). Tiller numbers and soil plant analysis development values of rice plants were significantly higher in most ground bamboo treatments (relative to controls) regardless of differences in bamboo organ source or refrigeration/fermentation treatment. Through enhancement of rice plant growth and suppression of aquatic weeds, rice yields were 1.76–2.06 times higher in the four ground bamboo treatments relative to controls. Application of ground bamboo did not noticeably reduce rice grain quality. Thus, the use of ground bamboo mulch has considerable potential in increasing the yield of high-quality rice, at least on a small scale.

Agrochemical-free rice farming has attracted interest for restoring paddy field biodiversity and producing safe food. Odonata are commonly used as a biodiversity indicator in these low-input farms. However, the effect of agrochemical-free rice farming on odonate diversity has rarely been assessed over the entire emergence period of these insects. We investigated whether different farming practices, such as conventional or natural (agrochemical-and fertilizer-free) cultivation, and associated water management strategies affect the emergence rates of Odonata in paddy field landscapes in central Japan. Weekly exuviae sampling in 2017 and 2019 suggested that odonate assemblages differed between conventional and natural paddy fields, with a higher number of taxa emerging from natural paddy fields. Contrary to expectations, conventional paddy fields had equivalent or higher emergence rates of all Odonata and two numerically dominant Sympetrum species. Peak emergence periods for numerically dominant taxa differed between the farming types, with the emergence of three Sympetrum species peaking in late June in conventional paddy fields and that of S. frequens peaking in early to mid-July in natural paddy fields. Our findings suggest that both conventional and natural paddy fields are important habitats for Odonata in Japan.

Marine mammal bycatch poses a particular challenge in developing countries, where data to document bycatch and its effects are often lacking. Using the Bycatch Risk Assessment (ByRA) toolkit, based on InVEST open-source models, we chose 4 field sites in Southeast Asia with varying amounts of data on marine mammals and fishing occurrence: Trat province in the eastern Gulf of Thailand, the Sibu-Tinggi Islands and Kuching Bay, Malaysia, and Kien Giang Biosphere Reserve in southwestern Vietnam. These field sites have similar species of coastal marine mammals, small-scale and commercial fisheries, and support for research from universities and/or management. In Thailand and Kuching, results showed changing patterns of fishing and Irrawaddy dolphin Orcaella brevirostris habitat use across seasons, showing how bycatch risk could change throughout the year. Risk maps for dugongs Dugong dugon in peninsular Malaysia highlighted patterns of bycatch risk concentrated around a mainland fishing pier, and revealed high risk in a northern subregion. In Vietnam, first maps of bycatch risk for the Irrawaddy dolphin showed the highest risk driven by intensive use of gillnets and trawling gear. ByRA pinpointed areas of spatial and seasonal bycatch exposure, and estimated the consequence of bycatch on local species, providing managers with critical information on where to focus bycatch mitigation and meet new global standards for US Marine Mammal Protection Act and other international regulation (e.g. Official Journal of the European Union 2019; Regulation 2019/1241) compliance. The toolbox, a transferable open-source tool, can be used to guide fisheries management, marine mammal conservation, spatial planning, and further research. KEY WORDS: Incidental bycatch · Marine mammals · Spatial risk assessment · Open-source GIS toolkit · Small-scale fisheries · Southeast Asia