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ESR prepress abstract   -  DOI:

A review of the conservation status and survey methods for the live-bearing sea star Parvulastra vivipara

Elisabeth M. A. Strain*, Ashlee Bastiaansen, Russell J. Thomson, Jemina Stuart-Smith, Ana Vila-Concejo, Maria Byrne

*Corresponding author:

ABSTRACT: The live-bearing sea star (Parvulastra vivipara), one of only six Asteroidea species globally that gives birth to live young, had an uncertain conservation status due to data deficiencies and historical differences in research methods. Restricted to southeast Tasmania, its distinctive reproductive strategy, coupled with limited distribution, low genetic diversity, and geographically isolated populations makes P. vivipara populations highly susceptible to localised and global extinction. Since the discovery of the species in 1969, ten different historical survey methods have been used to survey P. vivipara populations. Notably the survey area at these locations has increased through time as abundances of P. vivipara declined. In 2022, surveys revealed the persistence of P. vivipara populations at ten of fifteen historically documented locations. Five locations experienced local extinction of P. vivipara populations, three in the last two decades, and four locations had fewer than 150 individuals remaining. The density of P. vivipara has already experienced a decline of 90% from the first surveys in 1974-2001 to 2022. Based on the current trajectory, it is predicted that the density of P. vivipara will decline to one individual per square meter by 2033 and one individual per site by 2111, with some locations experiencing this decline even sooner. The rapid decline and restricted area of occupancy mean that P. vivipara qualifies for Critically Endangered status under IUCN Red List criteria A1 and B1. There is a pressing need for standardised and ongoing monitoring, management of key threats, and recovery strategies to bolster local and global P. vivipara populations against the threat of extinction.