Morphological differences along a chronological gradient of urbanisation in an endemic insectivorous bird of New Zealand

Urbanisation constitutes one of the most rapid human-induced environmental changes, developing at the expense of natural and semi-natural habitats. It often implies alterations of many abiotic and biotic factors and contributes to create new environmental conditions, including temperature, food resources, competition and predation. Despite increasing empirical evidence of intra-specific divergence in phenotypic traits (e.g., physiological, behavioural or morphological) between urban and rural individuals, such patterns have often remained disconnected from the underlying mechanisms involved. In the current study, we tested for divergence in functional morphological traits that are related to feeding ecology (i.e., bill morphology, body mass and condition) and/or to the locomotory performance in escaping from predators (i.e., wing, tarsus and tail morphology, body mass and condition) along a chronological gradient of urbanisation (old urban, recent urban and rural areas), using the New Zealand fantail, an endemic insectivorous passerine species. We found divergences in phenotypic traits related to bill morphology along the urban–rural gradient: birds inhabiting the old urban area had stubbier bills (i.e., shorter, deeper and wider bills) than those inhabiting the recent urban and rural areas. We did not detect any difference in locomotion-related morphological traits. Our results suggest the urbanisation-induced alteration in food resources may drive morphological divergence in bird populations. We emphasized the need for mechanistic and experimental studies, with a particular focus on resource-based mechanisms, to identify more precisely the morphological responses of urban populations to changes in food composition, and the resulting implications for communities in urban ecosystems.

     

The motivational mechanisms underlying active and high-strain work: consequences for mastery and performance

We test if the motivating potential of active work and the demotivating consequences of high-strain work can be explained by the “quality” of motivation experienced. Study 1, an experiment (N?=?205), revealed active work maintained intrinsic motivation and identified regulation (compared to baseline). High-strain work decreased these motivations. Moreover, demand was negatively related to mastery only at low control, through reduced intrinsic motivation. Demand was negatively related to task performance at low control, through reduced identified regulation. Study 2, an online survey (N?=?516 employees), revealed an energising effect of active work on intrinsic motivation and identified regulation, both of which had positive associations with job performance. A demotivating effect of high-strain work on intrinsic motivation was revealed, which had negative associations with job performance. In conclusion, internalised motivations are important mechanisms, through which active work protects and enhances mastery/performance, and through which high-strain work can deplete these outcomes.     

Getting New Staff to Stay: The Mediating Role of Organizational Identification

Newcomer turnover is a major cost to organizations, and the quality of new employees' experiences in the first few months is critical in determining whether they decide to stay or leave. In a study that focused on the first stage of newcomer socialization, we investigate the impact of perceptions of social validation from the team and the team leader, and perceived fairness of treatment on newcomers' identification with their work team and the organization, specifically measuring the group self‐investment components of identification. The mediating role of these levels of group self‐investment and of the imbalance (i.e. difference) between levels of self‐investment on turnover intentions was also tested. New staff (N=569) joining a large public‐sector organization completed a questionnaire about their socialization experiences in their first 6 months of their employment. Structural equation modelling revealed that social validation by the team and team leaders, and fairness of treatment, predict increased investment with the organization and with the team. Organizational‐level self‐investment and an imbalance in favour of investment with the organization over that of the team mediated decreases in turnover intentions. We conclude that organizations should provide newcomers with validation that promotes identification with their organization during this critical stage of socialization.