The relationship between oil prices and food prices is complex, and maize is the most prominent example. Whether the development of bioenergy will exacerbate the price increase of maize caused by the increasing price of oil is a topic that is attracting great attention. This paper studies the relationship between oil prices and maize prices. First, the effects of the development of biomass energy on maize price in theory is analyzed by constructing a theoretical model that includes the effects of the cost channel and the demand channel, while setting the maize–oil price ratio as a trigger for the demand channel. Then, this paper empirically analyzes the price data. Both theoretical and empirical analyses show the effects of the demand channel in the long term; that is, the effect of the development of bioenergy on maize prices is weak, and maize prices did not increase sharply. The effect of the cost channel is the main cause of the increases in the price of maize and other foods.

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Aim: The Eurasian otter (Lutra lutra) is a flagship species for global freshwater ecosystems. As one of the most widely distributed Palearctic mammals, the otter used to inhabit most provinces in China. However, after decades of relentless hunting and habitat degradation, the Sanjiangyuan Region is now one of last strongholds for this species in China. Currently, there still remains an enormous knowledge gap in basic information about this species. Available field information has mostly been acquired through camera trapping, and the reliability of this method is still being questioned considering the revealed underperformance in the monitoring for otters. Method: Research was conducted in Yushu City, Qinghai Province. We deployed surveillance cameras and camera traps in five monitoring sites with high otter occurrences from Oct. 2018 to May 2020. Using data collected from the

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Religious wildlife release is prevalent worldwide, especially in Asia countries. It is one of the anthropogenic pathways to cause biological invasions. Religious fish release is common on the Qinghai-Tibetan Plateau, yet few studies have assessed the influences of religious fish release on local species. In Yushu, a city on the Qinghai-Tibetan Plateau, we interviewed local people, conducted fish trap surveys in local rivers, and examined the diet of Eurasian otters Lutra lutra using a fecal DNA metabarcoding approach. We found that fish release started at least in 1980s -1990s in Yushu. Tibetan residents released fish in large amounts and released fish were usually exotic commercial fish purchased from market. Despite such long-term and intensive fish release activities, released fish were few in local rivers. On the other hand, Eurasian otters mainly prey on fish and released fish accounted for ~20% of relative read abundance of prey DNA in otters’ diet, indicating their high preference on released fish. Our study suggested that religious fish release may provide additional food resources for otters, whereas otters, as a top predator in local rivers, may deplete non-native fish once they were released and therefore reduce the probability of colonization of released fish, although further studies are required to assess otters’ impact. Our study revealed otters’ diet in Yushu, providing basic information for local otter management and conservation. Furthermore, it represents a case showing that native predators prey on religious released animals, implying a probable direction for controlling invasive species through native predator conservation.