Comparing ecological relevance of climate velocity indices.

Climate change is causing species ranges to shift. Population survival requires species to shift at a sufficient pace to accommodate with climate. However, estimating the velocity of climate change requires an assumption about its direction. This can be done via two alternative methods: the gradient-based methods and the recently introduced Monte-cArlo iTerative Convergence metHod (MATCH). In this work, we investigate how the rates of North-American birds and marine species range shifts correspond to the velocity of climate change (in the latitude, longitude and elevation/depth direction) calculated using either of these methods. These velocities are evaluated against the centroid of each considered species’ observed distribution range, based on the Audubon Christmas Bird Count and the NOAA Global Marine Data databases. We find that the MATCH method better describes the observed latitudinal and elevation/depth range shifts of the species, which is twice the Gradient performance. Developing robust method to evaluate the velocity of species could help in the planning of assisted migration.