Periodic Reporting for period 1 - PhoticEdge (Are species distributions constrained by biological timing mechanisms and the photic environment?)
Reporting period: 2022-02-01 to 2024-01-31
Organisms use abiotic cues, such as sunlight, to align their biology to the environment. However, the effect of daylength on species distribution is poorly understood. The EU-funded PhoticEdge project examined this relationship, using migratory songbirds captured in Sweden that had either a subpolar or polar breeding distribution or an equatorial or transequatorial migration strategy. Migratory songbirds were studied because they use photic cues for determining breeding, migration, and navigation. PhoticEdge is elucidating how the photic environment associated with the birds' breeding and wintering distributions influences their ability to align their biology to daily and annual cycles. This is providing insight into the interaction between species distributions and the photic environment, increasing knowledge of changes to biodiversity under global climate change. Main objectives of the project also included training the researcher and transfer of knowledge between the researcher and the hosting supervisor.
To address the scientific objectives, we completed experiments testing whether poleward displacement during summer and winter affected diel processes in the context of annual phenology. We completed four projects in which songbirds were subjected to a polar-summer photic environment, simulating a poleward displacement. These results are forthcoming, but preliminary results suggest that constant light challenges diel processes in songbirds compared to exposure to the local photic environment at the capture site. We additionally subjected one species of diurnally migrating songbird to an autumn polar photic environment during their first migration and found that photic cues are incorporated into the endogenous migratory program during migration. We also tested whether equatorial migrants can properly schedule annual processes by subjecting them to a southern-poleward photic-displacement of their normal overwintering range. Together, our results will demonstrate whether diel processes interact with annual temporal processes in the context of simulated poleward range shifts, which can have implications for whether migratory birds can track warmer temperatures poleward into novel photic environments in the northern breeding and southern overwintering ranges. The training of the researcher and transfer of knowledge between the researcher and the hosting supervisor was successful. The researcher gained valuable experience mentoring students and interns, and accomplished the goals of learning to design controlled experiments using songbirds. Bilateral transfer of knowledge also occurred by the researcher providing expertise on diel processes and polar environments and the supervisor providing expertise in annual migration, navigation, and experimental design using songbirds.
Overall, the training and knowledge obtained by the researcher and supervisor will be instrumental in future work pushing the state of the art for the effect of the photic environment on species distributions and the interaction among diel, annual, and photic processes in the context of climate change. The project is additionally pushing the state of the art by discovering how diel processes interact with annual migration. In this context, the project is elucidating how the endogenous migratory program incorporates photoperiod, which provides an understanding of how migratory birds can to shift ranges into novel photic environments at higher latitude. Combined, the project’s success can inform predictions of biodiversity.