Spatial synchrony at the extremes: Tail-dependence in temperature drives
tail-dependence in birds’ spatial synchrony across North America
Abstract
Environmental change is becoming synchronous across sites with frequent
emergence of extremes in recent years, with potential impacts on
species’ synchronous abundance over large scales. Analyzing 41 years of
breeding bird survey data across North America, we observed that some
birds showed mostly lower tail-dependent spatial synchrony (i.e.,
synchrony across sites at low abundances), while others showed mostly
upper tail-dependent spatial synchrony (i.e., synchrony across sites at
high abundances). We found that spatial synchrony in climate extremes
(i.e., tail-dependence in climate), not the dispersal trait (hand-wing
index), drove the spatial synchrony in abundance extremes (i.e.,
tail-dependence in abundance) up to 250 Km. Tail-dependence in high (or
low, respectively) temperature across sites caused lower (or upper,
respectively) tail-dependent spatial synchrony in abundance. In a
rapidly changing environment, these findings highlight the importance of
considering synchronized climatic extremes to assess species’
tail-dependent spatial synchrony across large scales.