No abstract

A fundamental question of current ecological research concerns the drives and limits of species responses to human-induced rapid environmental change (HIREC). Behavioural responses to HIREC are a key component because behaviour links individual responses to population and community changes. Ongoing fast urbanization provides an ideal setting to test the functional role of behaviour for responses to HIREC. Consistent behavioural differences between conspecifics (animal personality) may be important determinants or constraints of animals' adaptation to urban habitats. We tested whether urban and rural populations of small mammals differ in mean trait expression, flexibility and repeatability of behaviours associated to risk-taking and exploratory tendencies. Using a standardized behavioural test in the field, we quantified spatial exploration and boldness of striped field mice (Apodemus agrarius, n = 96) from nine sub-populations, presenting different levels of urbanisation and anthropogenic disturbance. The level of urbanisation positively correlated with boldness, spatial exploration and behavioural flexibility, with urban dwellers being bolder, more explorative and more flexible in some traits than rural conspecifics. Thus, individuals seem to distribute in a non-random way in response to human disturbance based on their behavioural characteristics. Animal personality might therefore play a key role in successful coping with the challenges of HIREC. Urbanisation is one of the fastest-occurring and most widespread human-induced environmental changes (e.g. 1,2). As urban environments expand more and more across the globe, wildlife must either adjust to rapid changes and human-modified landscapes, or experience severe declines and, ultimately, local extinction (e.g. 2,3). The urban environment presents wildlife with novel challenges, including an altered biotic environment with anthropogenic disturbances, modified competitive interactions, new predators and parasites, as well as altered abiotic factors such as water, soil, light and air pollution, noise, soil sealing, fragmentation and traffic (e.g. 2,4,5). As a result of these human-induced rapid environmental changes (HIREC 5), ecosystems are experiencing sharp declines in biodiversity worldwide (e.g. 1,2). A few species, however, are thriving and occur in high numbers in urban environments. A fundamental focus of current ecological and evolutionary research is to illuminate the drivers of the success of some animals in an urbanised world 3,6,7 because these "urban laboratories" might advance our understanding of fundamental eco-evolutionary processes and key theoretical concepts, including niche construction and community assembly as well as the role humans play in eco-evolutionary dynamics 8. The ability of an animal to adjust to novel challenges is likely to contribute to its ultimate success in urban environments (e.g. 3-5,9). Behavioural adaptations are expected to play a major role in coping with HIREC because behaviour largely determines how individuals in...

Balancing foraging gain and predation risk is a fundamental trade-off in the life of animals. Individual strategies to acquire, process, store and use information to solve cognitive tasks are likely to affect speed and flexibility of learning, and ecologically relevant decisions regarding foraging and predation risk. Theory suggests a functional link between individual variation in cognitive style and behaviour (animal personality) via speed-accuracy and risk-reward trade-offs. We tested whether cognitive style and personality affect risk-reward trade-off decisions posed by foraging and predation risk. We exposed 21 bank voles ( Myodes glareolus ) that were bold, fast learning and inflexible and 18 voles that were shy, slow learning and flexible to outdoor enclosures with different risk levels at two food patches. We quantified individual food patch exploitation, foraging and vigilance behaviour. Although both types responded to risk, fast animals increasingly exploited both food patches, gaining access to more food and spending less time searching and exercising vigilance. Slow animals progressively avoided high-risk areas, concentrating foraging effort in the low-risk one, and devoting >50% of visit to vigilance. These patterns indicate that individual differences in cognitive style/personality are reflected in foraging and anti-predator decisions that underlie the individual risk-reward bias.