When it comes to saving animals from extinction, many efforts are needed. Some of them seem very interesting to me. This is the case of the Northern Jaguar Project. They try to protect a large piece of land in Northern Occidental Mexico in order to ensure a large zone where jaguars could survive in a region that is considered as the nothern-most habitat of the jaguar.
They buy large pieces of land from ranches to help a group of around 120 jaguars live in a more confortable manner out of reach of most poachers and human expansion.
Actually, you can help them buy one acre (1/2 hectare or 4000 square meters) of ranch land for $49 in their Save-a-Spot for Jaguars program.