Rarity, often regarded only as a symptom of species decline, itself increases extinction risk. When species occur in low numbers or concentrated within a few populations, a singular stochastic event – fire, landslide, or storm – may eliminate an entire species. Moreover, rarity may reinforce population decline by reducing per capita reproduction (the Allee effect) and decreasing offspring viability when inbreeding results in the expression of deleterious alleles. Thus, conservation of rare species depends not only on identifying underlying causes of rarity, but mitigating risk associated with rarity. Amsonia kearneyana Woodson is a plant species native to southern Arizona with fewer than 400 known individuals in existence; and is a federally listed endangered species. Increasing abundance and viability of threatened and endangered species supports a legal mandate to prevent extinction of these imperiled species, while enhancing overall ecosystem performance, as rare species disproportionally influence ecosystem function and services (Mouillot et al. 2013). The overarching goal of this research is to enhance long-term viability of the rare species, Amsonia kearneyana Woodson. To accomplish this goal, we conducted a structured seed augmentation experiment, tested ex situ conservation as a pathway to recovery for t A. kearneyana in order to identify extrinsic and intrinsic causes of rarity, and develop a species habitat probability model to identify areas of possible existing, but unidentified, populations or areas suitable for introduction of novel populations via transplant.