Extended diurnal activity patterns of European rabbits along a rural-to-urban gradient

Effects of urbanization on the population dynamics of wildlife species range from entirely negative (leading to local population extirpation) to positive effects. Relaxed predation on species like European rabbits (Oryctolagus cuniculus) in cities not only lowers extrinsic mortality rates, but could also facilitate advantageous behavioral modifications, as less time needs to be invested in anti-predator behaviors. We studied diurnal activity patterns of rabbits along a rural-to-urban gradient in and around Frankfurt am Main (Germany), where population densities increase from the periphery towards the city center. Compared to individuals from rural sites, rabbits from urban and suburban sites spent, on average, more time outside their burrows, invested less time in anti-predator behavior, and showed reduced rhythmicity in daytime activity patterns, including a weaker midday resting phase. Anthropogenic disturbance was considerably higher at urban and suburban sites compared to rural ones; still, rabbit behavior was less affected by anthropogenic disturbance. This was confirmed experimentally by chasing the members of different social groups into their burrows: while rabbits at rural and suburban sites uniformly fled into their burrows, this was not the case in 93% of urban rabbit groups. Also, times until individuals reappeared above ground decreased when we repeated this measurement on several subsequent days. Our study provides further evidence that not only direct effects (like landscape alterations and altered resource availability), but also indirect effects (here: behavioral changes following altered predation regimes and subsequent habituation to other sources of disturbance) need to be considered when formulating predictions about how urbanization affects wildlife populations.