Ecological traps, which occur when animals mistakenly prefer habitats where their fitness is lower than in other available habitats following rapid environmental change, have important conservation and management implications. Empirical research has focused largely on assessing the behavioural effects of traps, by studying a small number of geographically close habitat patches. Traps, however, have also been defined in terms of their population-level effects (i.e. as preferred habitats of sufficiently low quality to cause population declines), and this is the scale most relevant for management. We systematically review the ecological traps literature to (i) describe the geographical and taxonomic distribution of efforts to study traps, (ii) examine how different traps vary in the strength of their effects on preference and fitness, (iii) evaluate the robustness of methods being used to identify traps, and (iv) determine whether the information required to assess the population-level consequences of traps has been considered. We use our results to discuss key knowledge gaps, propose improved methods to study traps, and highlight fruitful avenues for future research.

While the bluehead wrasse has long been used as a test species in sex allocation theory, there is no published evidence that sex change in this species is socially controlled. Here we show that removal of large terminal color phase (TP) males from local populations leads to sex and color change in the largest initial color phase (IP) females. In contrast, no sex changes occurred in control populations in which the TP males were handled but replaced, and in which only the IP males were removed. The response to removals was quite precise, resulting in a nearly one-to-one replacement of TP males. Large individuals that had been seen spawning as female males on the day prior to the manipulation, initiated male behaviors within minutes of the removal of the TP males and spawned in the male role the same day. Color changes were noted within a day and were distinct within four days. Sex change was verified by histological examination of the gonads of the changing individuals. All had functional testes, and all showed evidence of recent transition from the ovarian condition. Mature sperm can be produced in as little as eight days after the initiation of sex change.

In situ Sr-isotope analysis by laser ablation multi-collector ICP-MS is a potentially powerful tracer technique with widespread application to many fields of study. The usefulness of the method, however, depends very strongly upon the quality of data that can be obtained (compared with conventional ‘solution-based’ analyses), and the spatial resolution, particularly in samples with strong compositional zonation or fine-scale growth banding. In this contribution we show that highly accurate (∼50 ppm) and precise (external precision ∼125 ppm) analyses of carbonate materials can be obtained in situ and further demonstrate that, by utilising the aperture-imaging optics of an excimer laser system with appropriate time-resolved software, isotopic variations on the scale of tens of micrometres can be resolved. An example is shown using relatively small (∼500 μm diameter) otoliths from a diadromous fish species, Galaxias maculatus.