Population viability analysis of the Uruguayan Creole cattle genetic reserve

SummaryUruguayan Creole cattle are descended from animals brought by the Spanish conquerors. The population grew extensively without directional management and became semi-wild before the introduction of commercial breeds in the 19th century. Today only 575 animals remain, restricted to the San Miguel National Park. We performed a population viability analysis of this reserve using VORTEX v. 8.31 to study its demographic and genetic parameters, assess the environmental factors that affect its development, evaluate its future risk of extinction and test different management options. The probability of extinction in the next 100 years was always zero, even in the more pessimistic scenarios. The growth rate of the population was always positive and mostly affected by the mortality rate of calves. Population size increased rapidly up to carrying capacity, this being the only limiting factor for population growth. Retained heterozygosity was always above 90% and the inbreeding coefficient below 0.10. The analysis shows that the population is not at risk due to its genetic diversity and demographic structure, however all the individuals are concentrated in only one place. We suggest its subdivision into sub-populations located in different regions and connected by gene flow, decreasing the risk of extinction and accomplishing the conservation and self-sustainability goals.