A third of world's conifers under threat of extinction study claims "The overall picture is alarming," said Jane Smart, head of the biodiversity conservation group of the IUCN, the International Union for Conservation of Nature, grouping scientists, governments and environmental organisations. Craig Hilton-Taylor, manager of the Red List, which is updated twice a year, told Reuters that diseases were compounding existing threats from logging, pollution and forest clearance caused by a rising human population. And global warming might be making conifers, standing in the same place for hundreds or even thousands of years, vulnerable to new pathogens as temperatures and rainfall patterns changed, he said. The report said there were some successes. Better management and plantings of disease-resistant stock of Lawson's Cypress in California and Oregon had helped a recovery of trees that were once heavily traded as timber. Among other findings, scientists added the Santa Cruz Pupfish, which used to live in Arizona, a freshwater shrimp and a lizard known as the Cape Verde Skink to the list of extinct creatures. The Skink was last seen in 1916. It's taken a lot of surveys to conclude that it is extinct," Hilton-Taylor said. A total of 799 animals and plants are listed as having died out in the past 500 years or so.