Deforestation and fragmentation of crucial Sumatran tiger (Panthera tigris sumatrae) habitats from 2000 to 2012 increased their threat of extinction, reports a study in Nature Communications this week. However, tiger densities increased in those forests that remained, indicating that a greater focus on the preservation of forest is needed to protect the species from extinction.
Determining the distribution and population numbers of threatened species is essential for developing conservation efforts, but assessments have been impeded by discrepancies in how such numbers are calculated. Using new methods to calculate population numbers, Matthew Luskin and colleagues estimated the number of tigers across Sumatra in the past two decades. They compile published estimates of animal densities along with new, more-robust surveillance data (from camera traps and capture-recapture methods) that cover different forest types.
These data reveal that between 2000 and 2012, there has potentially been an overall decrease in tiger numbers of 16.6%, with rates of decrease varying across the island. However, in protected forests, tiger numbers have increased 4.9% per year since 1996. The results demonstrate that more efforts are needed to reduce deforestation to prevent the extinction of tigers in Sumatra, the authors conclude.