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Although the concept of connectivity is ubiquitous in ecology and evolution, its definition is often inconsistent, particularly in interdisciplinary research. In an ecological context, population connectivity refers to the movement of individuals or species across a landscape. It is measured by locating organisms and tracking their occurrence across space and time. In an evolutionary context, connectivity is typically used to describe levels of current and past gene flow, calculated from the degree of genetic similarity between populations. Both connectivity definitions are useful in their specific contexts, but rarely are these two perspectives combined. Different definitions of connectivity could result in misunderstandings across subdisciplines. Here, we unite ecological and evolutionary perspectives into a single unifying framework by advocating for connectivity to be conceptualized as a generational continuum. Within this framework, connectivity can be subdivided into three timescales: (1) within a generation (e.g., movement), (2) across one parent-offspring generation (e.g., dispersal), and (3) across two or more generations (e.g., gene flow), with each timescale determining the relevant context and dictating whether the connectivity has ecological or evolutionary consequences. Applying our framework to real-world connectivity questions can help to identify sampling limitations associated with a particular methodology, further develop research questions and hypotheses, and investigate eco-evolutionary feedback interactions that span the connectivity continuum. We hope this framework will serve as a foundation for conducting and communicating research across subdisciplines, resulting in a more holistic understanding of connectivity in natural systems. 

Acidification‐induced changes in neurological function have been documented in several tropical marine fishes. Here, we investigate whether similar patterns of neurological impacts are observed in a temperate Pacific fish that naturally experiences regular and often large shifts in environmental pH/pCO₂. In two laboratory experiments, we tested the effect of acidification, as well as pH/pCO₂variability, on gene expression in the brain tissue of a common temperate kelp forest/estuarine fish,Embiotoca jacksoni. Experiment 1 employed static pH treatments (target pH = 7.85/7.30), while Experiment 2 incorporated two variable treatments that oscillated around corresponding static treatments with the same mean (target pH = 7.85/7.70) in an eight‐day cycle (amplitude ± 0.15). We found that patterns of global gene expression differed across pH level treatments. Additionally, we identified differential expression of specific genes and enrichment of specific gene sets (GSEA) in comparisons of static pH treatments and in comparisons of static and variable pH treatments of the same mean pH. Importantly, we found that pH/pCO₂variability decreased the number of differentially expressed genes detected between high and low pH treatments, and that interindividual variability in gene expression was greater in variable treatments than static treatments. These results provide important confirmation of neurological impacts of acidification in a temperate fish species and, critically, that natural environmental variability may mediate the impacts of ocean acidification. 

Abstract Variability in primary producers' responses to environmental change may buffer higher trophic levels against shifts in basal resource composition. Then again, in instances where there is a lack of functional redundancy because consumers rely on a few species to meet their energetic requirements at specific times of the year, altered community production dynamics may significantly impact food web resilience. In high‐latitude kelp forests, a complementary annual phenology of seaweed production supports coastal marine consumers' metabolic needs across large seasonal variations in their environment. Yet, marine consumers in these systems may face significant metabolic stress under the pronounced low pH conditions expected in future winters, particularly if they lack the resources to support their increased energetic demands. In this study, we investigate how the growth and nutritional value of three dominant, coexisting macroalgal species found in subpolar kelp forests will respond to ocean acidification and warming in future winter and summer seasons. We find that the three kelpsMacrocystis pyrifera,Hedophyllum nigripes, andNeoagarum fimbriatumdiffer in their vulnerability to future environmental conditions, and that the seasonal environmental context of nutrient and light availability shapes these responses. Our results suggest that poleward fringe populations ofM. pyriferamay be relatively resilient to anticipated ocean warming and acidification. In contrast, ocean warming conditions caused a decrease in the biomass and nutritional quality of both understory kelps. Considering the unique production phenology ofH. nigripes, we emphasize that negative impacts on this species in future winters may be of consequence to consumer energetics in this system. This work highlights how interspecific variation in autotrophs' responses to global change can disrupt the diversity and phenological structure of energy supply available to higher trophic levels.