Most populations of giraffes have declined in recent decades, leading to the recent IUCN decision to upgrade the species to Vulnerable status, and some subspecies to Endangered. Translocations have been used as a conservation tool to re-introduce giraffes to previously occupied areas or establish new populations, but guidelines for founding populations are lacking. To provide general guidelines for translocation projects regarding feasibility, we simulated various scenarios of translocated giraffe populations to identify viable age and sex distributions of founding populations using population viability analysis (PVA) implemented in Vortex software. We explored the parameter space for demography and the genetic load, examining how variation in founding numbers and sex ratios affected 100 yr probability of population extinction and genetic diversity. We found that even very small numbers of founders (N ≤ 10 females) can appear to be successful in the first decades due to transient positive population growth, but with moderate population growth rate and moderate genetic load, long-term population viability (probability of extinction <0.01) was only achieved with ≥30 females and ≥3 males released. To maintain >95% genetic diversity of the source population in an isolated population, 50 females and 5 males are recommended to compose the founding population. Sensitivity analyses revealed first-year survival and reproductive rate were the simulation parameters with the greatest proportional influence on probability of extinction and genetic diversity. These simulations highlight important considerations for translocation success and data gaps including true genetic load in wild giraffe populations.

Most populations of giraffes have declined in recent decades, leading to the recent 24 decision to upgrade the species to vulnerable status, and some subspecies to endangered.25 1 Email: dereklee@psu.edu 2 | Lee et al. • Giraffe PVATranslocations have been used as a conservation tool to re-introduce giraffes to previously 26 occupied areas or establish new populations, but guidelines for founding populations are lacking. 27 To provide general guidelines for translocation projects regarding feasibility, we simulated 28 various scenarios of translocated giraffe populations to identify viable age and sex distributions 29 of founding populations using Population Viability Analysis (PVA) implemented in Vortex 30 software. We explored the parameter space for demography (population growth rates: λ = 1.001, 31 1.010, 1.024), and the genetic load (number of lethal equivalents: LE = 2.5, 6.29, 12.6), 32 examining how variation in founding numbers (N = 5 to 80 females) and sex ratios (M:F = 0.1 to 33 0.5) affected 100-year probability of extinction and genetic diversity. We found that even very 34 small numbers of founders (N ≤10 females) can appear to be successful in the first decades due 35 to transient positive population growth, but with moderate population growth rate and moderate 36 genetic load, long-term population viability (probability of extinction <0.01) was only achieved 37 with ≥30 females and ≥3 males released. To maintain >95% genetic diversity of the source 38 population in an isolated population, 50 females and 5 males are recommended to comprise the 39 founding population. Sensitivity analyses revealed first-year survival and reproductive rate were 40 the simulation parameters with the greatest proportional influence on probability of extinction 41 and genetic diversity. These simulations highlight important considerations for translocation 42 success, and data gaps including true genetic load in wild giraffe populations.43 viability 45 Giraffes (Giraffa camelopardalis) are endemic African ruminant ungulates, and one of only a 46 handful of extant terrestrial megaherbivores (Owen-Smith 1988). Most populations of giraffes 47 2018). Translocations have been used as conservation tools to re-introduce giraffes to previously 50 occupied areas or establish new populations (Winter et al. 2019), but quantitative guidelines for 51 establishing viable populations of translocated giraffes do not exist. 52 General guidelines for translocations suggest population modelling should be used to assist in the 53 assessment of project feasibility (IUCN 2013). Population modelling for translocation projects 54 can offer guidance on age-and sex-classes for founder populations by providing estimates of 55 population persistence, long-term viability, and genetic diversity (Seddon et al. 2007).56 Population viability analysis (PVA) is commonly used to predict the likely future status of a 57 population and thus offers a quantitative basis for evaluating alternative management strategies 58 (Boyce 1992, Morris and Doak 200...