Coping with climate change: can variable flow patterns facilitate poleward range shifts of marine species inhabiting equatorward current systems?
Cascade J. B. Sorte (1), Lauren L. M. Pandori (2), Shukai Cai (3) and Kristen A. Davis (4)
1 Department of Ecology and Evolutionary Biology, University of California, Irvine, csorte@uci.edu
2 Department of Ecology and Evolutionary Biology, University of California, Irvine, lmcquinn@uci.edu
3 Department of Civil and Environmental Engineering, University of California, Irvine, shukaic1@uci.edu
4 Department of Civil and Environmental Engineering, University of California, Irvine, davis@uci.edu
Marine communities face continuing and accelerating climate change; however, we are still far from being able to predict which species will go extinct and which will persist in future climates. To make these predictions, we need to understand the efficacy of mechanisms that allow species to persist in altered environmental conditions, including poleward range shifts. Such shifts may be particularly challenging for marine metapopulations existing within strongly advective coastal systems where currents flow in the opposite direction of climate shifts, e.g. in eastern boundary current regions. We developed an integrative approach to determine whether variation in flow patterns (due to reversals in wind direction) along the western U.S. can facilitate poleward transport – and, thus, promote persistence – of marine species with planktonic larvae. We paired intensive time-series observations of mussel recruitment in the northeastern Pacific with simulated larval transport using a high-resolution,
3D coastal circulation model. We used the modeling results to predict the proportion of individuals in each recruiting cohort that originated from northern versus southern sources. Both field observations and model results showed that mussel recruitment rates increased during periods of poleward, downwelling-favorable winds. Furthermore, the level of recruitment from southern sources was related to wind transitions suggesting that poleward range shifts will be partly dependent on future changes in wind patterns in these systems.