Climate change is transforming the structure of biological communities through the geographic extension and contraction of species’ ranges. Range edges are naturally dynamic, and shifts in the location of range edges occur at different rates and are driven by different mechanisms. This leads to challenges when seeking to generalize responses among taxa and across systems. The figure below focuses on warming-related range shifts in marine systems to describe extensions and contractions as stages, including a sequence of (1) arrival, (2) population increase, and (3) persistence, or by contrast (1) performance decline, (2) population decrease and (3) local extinction. This stage-based framework can be broadly applied to geographic shifts in any species, life-history stage, or population subset. Ideally the probability of transitioning through progressive range shift stages could be estimated from empirical understanding of the various factors influencing range shift rates. While abundance and occupancy data at the spatial resolution required to quantify range shifts are often unavailable, case studies conducted in this study illustrate how diverse evidence sources can be used to stage range extensions and contractions and assign confidence that an observed range shift stage has been reached. Read more about this study and its suggestions for future directions by clicking on the title above.