3.3 Species Redundancy

Redundancy describes the ability of a species to withstand catastrophic events. Redundancy is characterized by having multiple, resilient populations distributed within the species’ ecological setting and across the species range.

Redundancy reduces the species’ extinction risk if a portion of the species’ range is negatively affected by a natural or anthropogenic catastrophic disturbance. Species that have resilient populations spread throughout their historical range are less susceptible to extinction (Carroll et al. 2010, entire, Redford et al. 2011, entire). Redundancy gauges the probability that the species has a margin of safety to withstand or can bounce back from catastrophic events (such as a rare destructive natural event or episode (e.g. disease) involving many populations). Redundancy is measured by the number of populations, their resiliency, and their distribution (and connectivity). Thus, high redundancy for the eastern indigo snake is defined as multiple resilient populations distributed throughout representative areas (ecological and genetic) of the species’ historical range. Maintaining connectivity among redundant populations is important for allowing immigration and emigration between populations and increases the likelihood of recolonization should a population become extirpated.