Long-term monitoring of wild bee communities at fixed locations using a consistent sampling procedure has been rare, although declines in their diversity and abundance due to anthropogenic impacts are a major concern. At two sites in urban green areas in Sapporo city, northern Japan, where wild bee surveys were conducted in 1959, 1979, 1989, 2018, and 2019, the number of individuals of bee genera was recorded. Patterns of seasonal changes in bee abundance collected at weekly censuses differed between 1979–1989 and 2018–2019. The total bee abundance collected in annual surveys consisting of standardized censuses demonstrated 50% and 41% declines at the two sites from 1959–1989 to 2018–2019. Among the 16 genera found in the surveys, 3 abundant genera, Andrena, Lasioglossum, and Ceratina, always exhibited lower abundance in 2018–2019 than in 1959–1989 at both sites. The remarkable declines in wild bee abundance should be examined in relation to various possible factors of anthropogenic impacts.

中文翻译：

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60 年来的野生蜜蜂调查显示，日本北部城市绿地的蜜蜂数量显着减少

尽管人为影响导致野生蜜蜂群落多样性和丰度下降是一个主要问题，但使用一致的采样程序对固定地点的野生蜜蜂群落进行长期监测的情况很少见。在日本北部札幌市城市绿地的两个地点，分别于1959年、1979年、1989年、2018年和2019年进行了野生蜂调查，记录了蜂属的个体数量。1979-1989 年和 2018-2019 年每周普查收集的蜜蜂丰度季节性变化模式有所不同。由标准化普查组成的年度调查收集的蜜蜂总丰度显示，从 1959 年至 1989 年到 2018 年至 2019 年，这两个地点的蜜蜂丰度分别下降了 50% 和 41%。在调查发现的16个属中，3个丰富的属，Andrena、Lasioglossum和Ceratina，在两个地点2018-2019年的丰度始终低于1959-1989年。应结合各种可能的人为影响因素来研究野生蜜蜂丰度的显着下降。