Sunday marks World Wildlife Conservation Day. According to a recent report by the Zoological Society of London and World Wildlife Fund, the global wildlife population has dropped significantly. The analysis indicates that wildlife populations plummeted by 58 percent between 1970 and 2012. It looked at 3,700 different species of birds, fish, mammals, amphibians and reptiles - about 6% of the total number of vertebrate species in the world.

A WWF official said that for freshwater species alone, the decline stands at 81 percent since 1970. Researchers conclude that vertebrate populations are declining by an average of 2 percent each year. They warn that if nothing is done, wildlife populations could fall by two-thirds below 1970 levels by the end of the decade. Still, some researchers have reservations about the report’s approach.  They say it is "broadly right, but the whole is less than the sum of the parts.”