Re-introduction of the pampas deer in Iberá Nature Reserve, Corrientes, Argentina

Summary

The pampas deer (Ozotoceros bezoarticus), Near Threatened globally and Endangered in Argentina, had gone extinct around the Iberá Nature Reserve in Corrientes, though roughly 1,500 remained on private cattle ranches nearby, land increasingly converted to pine plantations or intensive grazing. The Conservation Land Trust developed a government-approved recovery plan, bringing in Brazilian expert Mauricio Barbanti to design capture and pre-release methods for deer that live in flooded grasslands impassable by vehicle and must be darted from a specially platformed tractor. Because no landowner would allow captures on their land, the Trust bought its own property in prime habitat, excluded cattle, and conducted controlled burns before translocating founders into an acclimation pen at San Alonso reserve starting in June 2009; early campaigns suffered notable mortality, including two of the first five deer, before technique refinements reduced losses to near zero later on. Translocations then expanded to San Nicolás, where dispersal, drowning and deaths in outside pine plantations forced a halt to further releases there, and a third population began at Rincón del Socorro in 2015. By June 2015, San Alonso had grown to an estimated 55-60 animals with 48 fawns identified, an 86% annual pregnancy rate, 90% annual survival, and a calculated 33% annual growth rate. Major obstacles included the difficulty of capturing a fragile species, distrustful landowners, and a damaging historical precedent from a failed 1960s capture operation that left Argentine conservation culture wary of proactive management. The project rates itself successful, crediting long-term commitment, expert advisors, a cohesive team, and a culture of learning from early losses.