We investigated the effects of undestroyed strips of winter cover crops in maize fields on carabid community composition, and on the distribution of three ecological traits: diet, wing status and body size. This dataset contains 2 csv files: 1) carabid species abundance in samples collected in 12 fields, in the undestroyed strips as well as the surrounding cropped areas and margins; 2) carabid species traits. The dataset is described in more details in the attached readme file and further precisions are given in the related publication.