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Biological invasions are widely recognised as a significant threat to biodiversity, a driver of global change and a relevant economic problem. Actions to control or eradicate invasive alien species (IAS) can cause great controversy, especially when targeted species are charismatic. Thus, better understanding people's perceptions of invasive species is key for ensuring more effective IAS management. The ring-necked parakeet (Psittacula krameri) and the monk parakeet (Myiopsitta monachus) are two of the most successful avian invaders worldwide, causing several ecological and socio-economic impacts in recipient regions. We used image-based questionnaires to assess differences in people's perceptions of recently established ring-necked and monk parakeet colonies in an urban environment (Porto, Portugal). Most participants recognised both species and had a positive perception of the parakeets, with respondents' education, gender and age influencing their perception. Potential ecological, economic and social impacts caused by these species do not seem be widely acknowledged yet, likely due to the limited awareness of IAS or the incipiency of their impacts in the area. Our results suggest future actions to manage feral parakeet populations in the area will likely be met with public opposition. While increased public literacy about IAS might help improve risk awareness, complementary tools should be used to promote support for potential interventions. Social assessments are vital to identify, evaluate and address social costs and benefits of IAS. Further research should adopt a multidisciplinary approach to foster communication in IAS management actions, implementing effective and sustainable measures to tackle biological invasions by charismatic vertebrates. [ABSTRACT FROM AUTHOR]

Understanding the factors influencing the establishment of non-native species is pivotal with regards to the development of effective biosecurity policies. In this paper, we aim to assess the role of climate matching, trade patterns and breeding origin as drivers of establishment success of introduced lovebirds (Agapornis species). A comprehensive database on the worldwide distribution of eight species of non-native lovebirds (including establishment success and population size from 21 countries spanning 27 years) was compiled. We combined climate-based species distribution models with environmental niche analyses to evaluate environmental suitability and potential niche shifts in the introduced range of lovebirds. Then, we tested whether combining habitat suitability with information on trade, introduction effort and breeding origin (captive-bred or wild-caught) of imported birds can improve model predictions at the country level. Although climate-based models fit well with the current distribution of non-native lovebirds at 5-arcminute resolution and significant niche similarity was found for 3 species, we also observed successful establishments in areas climatically distinct from those occupied in native ranges. At the country level, only a significant relationship between the number of established populations and both the number of introduction sites and the year of first importation was observed. A significant effect of breeding origin was not found, but most traded birds had a captive-bred origin. Our work contributes to the growing evidence of the complexity of the invasion process and the difficulty of pre-introduction invasion assessments based solely on the characteristics of the recipient environments for the Agapornis species. Surveillance protocols should be applied to both wild-caught and captive-bred lovebirds, as additional data becomes available to better tease apart the role of origin in those species. [ABSTRACT FROM AUTHOR]

Climate similarity favors biological invasion, but a match between seasonality in the novel range and the timing of life cycle events of the invader also influences the outcome of species introduction. Yet, phenology effects on invasion success have generally been neglected. Here we study whether a phenological mismatch limits the non-native range of a globally successful invader, the Ring-necked parakeet, in Europe. Given the latitudes at which parakeets have established across Europe, they breed earlier than expected based on breeding dates from the native Asian range. Moreover, comparing the breeding dates of European populations to those of parakeets in the native Asian range, to five native breeding bird species in Europe and to the start of the growing season of four native European trees shows that the discrepancy between expected and actual breeding phenology is greater in northern Europe. In northern European populations, this temporal mismatch appears to have negative effects on hatching success, and on population growth rates in years that are colder than average in the first six months. Phenological mismatch also can explain why parakeets from African populations (that are more likely to breed in autumn) have been poor invaders compared to parakeets from Asia. These lines of evidence support the hypothesis that the reproductive phenology of the Ring-necked parakeet can be a limiting factor for establishment and range expansion in colder climates. Our results provide growing support for the hypothesis that the match between climate seasonality and timing of reproduction (or other important life cycle events) can affect the establishment success, invasive potential and distribution range of introduced non-native species, beyond the mere effect of climate similarity. [ABSTRACT FROM AUTHOR]

Invasive species face new environmental conditions in their areas of introduction. A correct timing of reproduction is crucial for the successful adjustment of individuals to their environments, yet the temporal aspects of the niche are a neglected subject in the study of biological invasions. When introduced, exotic species could successfully invade new habitats by making use of ecological opportunities, e.g. empty temporal Eltonian niches. Specifically, they may achieve this via conservatism of their native reproductive phenology and/or via plasticity in their reproductive timing. Here we compare the reproductive phenology of a marshland passerine community composed of five successfully established tropical exotic species and twelve coexisting Mediterranean native species along four consecutive years. Both groups showed large differences in their phenology, with exotics reproducing along more months and later in the year than natives. One exotic species even breeds only in late summer and early autumn, when virtually all natives have ceased breeding and when overall bird abundance as well as primary production in cultivated areas (rice fields) were highest. Nonetheless, estimates of population sizes and juvenile survival rates in the study area suggest that late breeding is not maladaptive but instead highly successful. The striking difference in reproductive timing suggests that the exotics may be taking advantage of a vacant Eltonian temporal niche, possibly generated by high resource availability in human-transformed habitats (rice fields and other croplands) in the study area. This study highlights the need to also consider the temporal aspects of the niche when studying invasions. [ABSTRACT FROM AUTHOR]

Speciation-the origin of new species-is the source of the diversity of life. A theory of speciation is essential to link poorly understood macro-evolutionary processes, such as the origin of biodiversity and adaptive radiation, to well understood micro-evolutionary processes, such as allele frequency change due to natural or sexual selection. An important question is whether, and to what extent, the process of speciation is 'adaptive', i.e., driven by natural and/or sexual selection. Here, we discuss two main modelling approaches in adaptive speciation theory. Ecological models of speciation focus on the evolution of ecological differentiation through divergent natural selection. These models can explain the stable coexistence of the resulting daughter species in the face of interspecific competition, but they are often vague about the evolution of reproductive isolation. Most sexual selection models of speciation focus on the diversification of mating strategies through divergent sexual selection. These models can explain the evolution of prezygotic reproductive isolation, but they are typically vague on questions like ecological coexistence. By means of an integrated model, incorporating both ecological interactions and sexual selection, we demonstrate that disruptive selection on both ecological and mating strategies is necessary, but not sufficient, for speciation to occur. To achieve speciation, mating must at least partly reflect ecological characteristics. The interaction of natural and sexual selection is also pivotal in a model where sexual selection facilitates ecological speciation even in the absence of diverging female preferences. In view of these results, it is counterproductive to consider ecological and sexual selection models as contrasting and incompatible views on speciation, one being dominant over the other. Instead, an integrative perspective is needed to achieve a thorough and coherent understanding of adaptive speciation. [ABSTRACT FROM AUTHOR]

The parasite manipulation hypothesis predicts that parasites should be selected to manipulate host behaviour to facilitate transmission to the next host. The bivalve Macoma balthica burrows less deep when parasitized by the trematode Parvatrema affinis. Shallow burrowing increases the likelihood of ingestion by birds, their final hosts, and therefore this has been interpreted as manipulation by the parasite. When unparasitized, M. balthica displays seasonal changes in burrowing depth, becoming less accessible to predators in winter. If shallow burrowing of parasitized individuals is due to direct manipulation by the parasite, the availability of parasitized individuals should be high throughout the year, or at least especially in the season when most birds are present and potential transmission rates are highest. We compared burrowing depths of parasitized and unparasitized individuals in a single population during seven consecutive years. Parasitized individuals showed reduced burrowing depths but, in contrast to the prediction, the effect of parasites on availability to predators was smallest, not largest, in the season with the highest bird numbers. The parasite P. affinis competes for energy with the host, and M. balthica with low energy stores are known to reduce depth of burrowing. When we included size-corrected somatic ash-free dry mass (as an estimate of the energy stores) in our statistical analysis, the effect of infection on burrowing depth disappeared. Thus the effect of infection on burrowing depth is likely to be an unavoidable, indirect effect of the channelling of energy towards the parasite, causing the starving individual to take greater risks in the acquisition of food. Since both the seasonal pattern and the magnitude of increased availability of parasitized individuals are inadequate, the increased exposure of parasitized M. balthica to the final host does not seem to represent an example of adaptive host manipulation by the parasite. [ABSTRACT FROM AUTHOR]