Hurricane Impacts on the Population Genetics of an Endangered Ecosystem Engineer

ABSTRACT Stochastic events such as hurricanes can influence the survival and consequently distribution and abundance of various taxa. The Key Largo woodrat ( Neotoma floridana smalli ) is an endangered subspecies and an ecosystem engineer endemic to its namesake island in the Florida Keys that has evolved with regular hurricane disturbances. Yet, climate change has led to more frequent and stronger storms which could exacerbate the immediate threat to these rodents since their population is already limited in distribution and threatened by invasive predators. Therefore, understanding how the woodrat population responds to such events can provide important information for future conservation efforts. To assess how the Key Largo woodrat population responded to a major hurricane, we estimated genetic diversity, effective population size, and spatial genetic structure before and after Hurricane Irma—a Category 4 storm that made landfall in the Keys in 2017. Despite overall low genetic diversity and effective population size pre‐ and post‐Hurricane Irma, we observed increases in both metrics post‐hurricane as well as shifts in spatial genetic structure. These results indicate that flooding from the hurricane likely drove a mixing of family groups as woodrats took refuge in trees and stick‐nests and then likely sought alternative green‐up resources following the storm. As climate change drives more intense storms and rising sea levels, these adaptive behaviors will become more important for the persistence of this fragile island population.