Spatial and temporal associations between fallow fields and Greater Painted Snipe density in Japanese rice paddy landscapes

Fallow fields provide suitable habitats for many farmland species in agricultural landscapes. Although the loss of fallow fields in the last few decades may be one of the major causes of the decline in farmland biodiversity, quantitative studies investigating the spatial and temporal associations between fallow fields and abundance of rice paddy organisms are few. This study focused on the Greater Painted Snipe (Rostratula benghalensis), a widespread wetland bird species in Asian rice paddies. We conducted replicated playback surveys in three regions of central Japan during the breeding seasons of 1997, 2006, 2007, 2018, and 2019. N-mixture models and model-selection approaches revealed positive associations between the immigration rate of Greater Painted Snipes and the area of wet fallow fields in 1997, when the species was still relatively common. Both observed and estimated densities showed (1) a severe decline in the population of Greater Painted Snipes in the Tsuchiura and Kasumigaura regions over a recent 22-year period in accordance with the reduction of fallow fields and (2) persistence of both wet fallow fields and Greater Painted Snipes in the Abiko region in 2018 and 2019. These results indicate that the loss of wet fallow fields since the late 1990s was associated with the decline of the Greater Panted Snipe population in Japanese agricultural landscapes. Our study highlights the potential importance of fallow fields for population trends of farmland birds and the necessity for their maintenance through, for example, agri-environmental schemes, in rice-producing countries

Highly ordered 3D macroporous scaffold supported Pt/C oxygen electrodes with superior gas-proton transportation properties and activities for fuel cells

© The Royal Society of Chemistry 2015. An oxygen electrode finds many applications in various electrochemical energy conversion devices such as fuel cells and metal-air batteries. Highly efficient gas-proton transportation at the electrode is very important to enhance the power density of these devices. Herein, we report the construction of a highly efficient oxygen electrode with substantially improved proton conductivity and gas transportation properties using three dimensionally ordered macroporous Nafion/Cs2.5H0.5PW12O40, 3DOM Nafion/CsHPW, scaffold supported Pt/C nanocomposites. The best results were obtained for cells with 3DOM Nafion/CsHPW with 10% CsHPW, achieving a maximum power density of 955 mW cm-2, 31% higher than 730 mW cm-2 for the cell with the conventional Nafion-binder based oxygen electrode. The proton conductivity of the 10% 3DOM Nafion/CsHPW catalyst layer is 1.56 × 10-2 S cm-1, 112% higher than 7.35 × 10-3 S cm-1 measured for the conventional catalyst layer with the Nafion binder. The results demonstrate the significant advantages of the oxygen electrodes with the Pt/C-3DOM Nafion/CsHPW architecture over the conventional Nafion-binder based ones, with the significantly enhanced proton conductivity of uniformly distributed CsHPW nanoparticles (NPs) and much better gas diffusion properties of the 3DOM architecture