As climate changes, species? ability to spatially track suitable climate depends on their capacity to migrate, a function of their population growth and dispersal capacity. Migration lags can ameliorate the climate experienced at species? expanding range edges as conditions become increasingly similar to those of the range core. When this boosts species? growth rates, migrations accelerate.
As part of my Ph.D. work, I used simulations of a spreading population with an annual life history to explore the consequences of variation in demography across climatic gradients for the dynamics of climate induced range shifts. I found that climate amelioration following a migration lag can enable species to accelerate their migration and potentially reach the climate velocity. Species with high dispersal capacity require less climatic amelioration and experience smaller range contractions during climate change than species with lower dispersal.
Acceleration of migration due to climate amelioration can interact with acceleration due to dispersal evolution, and do so in sometimes complex ways such that cause the spread velocity to transiently exceed the climate velocity. Failing to account for the acceleration of migration due to climate amelioration can lead to erroneous conclusions about species capacity to spatially track suitable climate.