Geographic range shifts under climate change: what will accelerated warming do?
Mathematical Biosciences Institute, The Ohio State University
(September 26, 2013 10:20 AM - 11:15 AM)
Rapid climate warming has caused species across the globe to shift their geographic ranges poleward in latitude or upward in elevation. We naturally ask: will species be able to keep up with climate warming? To answer this question, I considered a mathematical model for a single-species population with distinct growth and dispersal stages.
The model is based on an integrodifference-equations framework, and is thus able to accommodate a diverse assortment of dispersal mechanisms. I incorporated climate warming by letting the niche curve, a curve describing environmental suitability for population growth on a spatial gradient, shift in one direction. The equation thus becomes non-autonomous. This equation can prescribe climate-warming scenarios and environmental heterogeneity in a versatile way. I compared different warming scenarios, and in this talk I will show that acceleration of climate warming imposes extra burden on the species compared with constant-speed warming, even if the amount of warming is the same over the same period of time. There is also a bifurcation phenomenon in this problem: under constant-speed warming, the population may fail to persist, and go extinct, if climate warming is too rapid. The threshold speed for persistence, or the critical speed, can be viewed as the species’ ability to keep up with climate warming. I will show that this critical speed depends both on the species’ growth and its dispersal.