Oosthuizen et al OA data

Urbanisation and its associated ecological disruptions, such as artificial light at night (ALAN), is of growing concern to wildlife. The general behaviour of African rodents is poorly studied and as a result, their responses to environmental perturbations, such as ALAN. We investigated the locomotor activity of the Angoni vlei rat (<i>Otomys angoniensis</i>), to ascertain its temporal niche and its responses to ALAN. The literature provides inconsistent reports regarding the temporal niche of this species. We investigated its temporal niche under standard laboratory conditions, under natural environmental conditions and under an ALAN treatment in the laboratory. The vlei rats exhibited nocturnal activity both under laboratory and natural ambient conditions. They did not reduce their activity in the presence of 2 Lux ALAN, but the amplitude of their activity increased almost three-fold under natural conditions. Compared with strictly nocturnal animals, the activity of <i>O. angoniensis </i>was not masked by light and more similar to that of a diurnal species. In nature, vlei rats live under dense grass, and therefore their predominantly nocturnal activity observed in captivity could be ascribed to the lack of adequate cover during experiments. The greater activity under natural environmental conditions could be a consequence of a combination of brighter daytime light and natural temperature cycles. Therefore, we suggest that although vlei rats display nocturnal activity in the laboratory, they may be more diurnal in their natural habitat. We propose that urbanisation will affect vlei rats more intensely in terms of habitat degradation, fragmentation and destruction than by ALAN.