Environmental vulnerability of amphibians. Many species of amphibians are declining...

Environmental vulnerability of amphibians. Many species of amphibians are declining due to dramatic changes in the environment. The environmental vulnerability of amphibian species native to Mexico was examined in Amphibian & Reptile Conservation (Aug. 2013). The researchers quantified this decline using a modified Environmental Vulnerability Score (EVS) algorithm. Scores ranged from 3 to 20 points, with higher scores indicating a greater level of environmental vulnerability. EVS scores for 382 snake species were determined and are summarized in the table below. Let x represent the EVS score for a randomly selected snake species in Mexico.