Adopt A Ranger
The single greatest immediate threat to the loss of species of plants and animals in the world is the lack of field staff in protected areas in developing countries. Without field staff, protected areas will be transformed into agricultural land and wildlife gets hunted to extinction.
The worldwide staffing need in developing countries is about 175,000, of which 140,000 rangers and 35,000 professional and administrative staff. Since half of the protected areas in those countries lack any staff at all, and the other half is at least 50% short, Adopt A Ranger (AAR) estimates that the shortage of rangers is about 105,000 and of other staff about 27,000. The immediate threat of shortage of field staff is probably 10 times greater than that of climate change.
AAR is the only organization in the world addressing this problem by raising awareness, political lobbying and fundraising.