【生態】英国におけるアナグマの社会集団の数

The number of badger social groups is estimated to have increased by approximately 100% in England between 1985-1988 and 2011-2013 according to new research published in the journal Scientific Reports. Over the same period, researchers found little change in Wales, estimating that the overall change across England and Wales amounted to 88%. The authors caution, however, that on their own, badger sett surveys are limited in their suitability for estimating populations of individual animals, as sett characteristics are a poor predictor of badger numbers and group size can vary widely.

Jo Judge and colleagues used survey data identifying badger setts at sites across England and Wales from 2011-2013 as a proxy for badger social groups and compared them to data from similar surveys conducted in 1985-1988 and 1994-1997. These surveys used similar methodologies, although variation arising from the use of experienced volunteers in the earlier surveys and trained professionals in this current survey cannot be excluded. In addition to providing insight of the comparative abundance of badger social groups over 25 years, the data from the 2011-2013 survey also provide information about current badger sett distribution. The authors estimate that, over the period 2011-2013, active main badger setts were present in 34.4% of rural 1 km squares in England and Wales and that the total number of main badger setts, and hence the number of social groups, in rural England and Wales was 71,600.