Using Population Viability Analysis (PVA) to inform and adapt ex situ conservation activities benefitting a Critically Endangered butterfly

Population viability analysis (PVA) can be a useful decision-support tool
to leverage uncertainty to avoid conservation hesitancy and paralysis. We
developed a novel PVA model to help evaluate the effectiveness of a range
of ex situ management options for the Critically Endangered Poweshiek
skipperling butterfly.  The PVA indicated that the last three
known United States populations face high likelihoods of extinction in the
absence of supportive ex situ management, particularly when
population sizes and in situ survival rates are low. Modeling indicated
that a headstarting program initiated in 2017 to reinforce these
populations was only likely delaying extirpation. Persistence
probabilities fell once the program was concluded, regardless of
population size or survival rate. An alternative ex situ breeding
program provided significant boosts to the persistence of all populations
by producing significantly more individuals available for releases than a
headstarting program reliant on in situ population sizes could provide.
Withholding individuals to establish a large ex situ breeding population
did not impose a notable penalty to wild populations and improved
persistence. Persistence was boosted further when an ex situ
breeding program is combined with headstarting to reinforce populations.
Based on these model outcomes, we elected to pivot management strategies
from headstarting to reinforcement via an ex situ breeding
program.  Effective PVAs are contingent on the incorporation of
as much information as possible, acknowledgement of uncertainty, and
flexibility. PVAs provide research opportunities and have been
under-utilized in insect conservation. Our model is likely the first to
link ex situ management to in situ dynamics for an invertebrate.