The importance of diurnal and nocturnal activity and interspecific interactions for space use by ants in clear‐cuts

1. Full sunlight conditions in open clear‐cuts may limit the activity of ants as soil surface temperatures reach lethal levels. Therefore, differences may be expected between the diurnal and nocturnal activity of ants, and in the interactions between ant species. These predictions, however, have been poorly investigated so far. 2. The circadian activity of ants in clear‐cuts in managed forests in Poland was investigated. Repeated counts of ants were performed during the day and the following night at the clear‐cut edge and in the clear‐cut interior. Interspecific interactions and the effect of plant coverage were also considered. 3. Abundances of Formica fusca Linnaeus and red wood ants were higher during the day, whereas Myrmica were more common at night. Formica fusca, Lasius and red wood ants were more common at the clear‐cut edge than in the interior. Myrmica showed the opposite pattern, but at night, its numbers increased at the edge. Plant coverage positively affected F. fusca and red wood ants. 4. Red wood ants tended to be negatively associated with Lasius, whereas they were neutral for F. fusca. The negative association of red wood ants and Myrmica was stronger during the day compared to night. 5. The time of day was a strong driver of ant activity in the clear‐cuts, whereas the distribution of red wood ants was of lesser importance. It is concluded that circadian activity may substantially contribute to niche separation between coexisting species, therefore, studies performed exclusively during the day cannot reflect the real structure of the community.