Safety in Numbers Does Not Apply for Northern Long-Eared Bats
In research published this week in the macroecology Journal, Global Ecology and Biogeography, a team of researchers compared four decades of population counts of North American bats before and after the emergence of white-nose syndrome to the situation in Europe, where the disease is endemic.
Most of what they discovered isn’t that surprising; white-nose syndrome is responsible for a 10-fold decrease in the abundance of North Americas hibernating bats and has caused extensive local extinctions.
The team also confirmed, at least in five out of six bat species they studied, the belief that the larger a population is, the lower the risk it has of becoming locally extinct.
However with the northern long-eared bat (Myotis septentrionalis), the species most affected by WNS, that logic didn’t apply. Extinction risk remained constant regardless of the colony size.
This evidence—bad news for a species who the USFWS are on the fence about listing as endangered—shows that a disease can potentially eliminate numerical rarity as the being the primary risk for extinction and highlights the broad influence species interactions have over a species abundance, occurrence and extinction.