Are Springs Important in the Post-fire Revegetation of Semiarid, Snow-dominated, Mountainous Watersheds?

Abstract:

Semiarid, mountainous watersheds are particularly susceptible to wildfires due to their dense forests and dry conditions. These watersheds are critically important sources of water and habitat for human and ecological communities in an otherwise water-scarce environment. Forest fires severely impact these watersheds through loss of vegetation, increases in erosion, decreases in water quality, and decreases in recharge. In addition, soil hydrophobicity, overland runoff, and erosion in post-fire watersheds create conditions where it is difficult for burned areas to re-vegetate within the months following a wildfire. What role do perennial springs play in post-fire re-vegetation? We hypothesize that revegetation originates around perennial springs since the springs and spring-runs are continual sources of water where new seeds can sprout and where burned vegetation can recover. We test this hypothesis in a snow-dominated, semiarid, mountainous watershed in the Chuska Mountains, located on the Navajo Nation in New Mexico and Arizona, following a wildfire that occurred in June 2014. NDVI was estimated in the watershed before and after the June 2014 fire using remotely sensed data. Photographs from digital trail cameras were used to capture the growth of vegetation/absence of growth on burned slopes with/without springs following the fire. The remote sensing data and trail camera photos indicate that revegetation is concentrated around springs. Springs act as “fountains” for regrowth of vegetation in the watershed following wildfires since they are dependable sources of clean water in a post-fire landscape commonly characterized by decreased infiltration and decreased water quality. An improved understanding of the role of springs in post-wildfire revegetation may enhance and prioritize watershed restoration and protection practices following a wildfire.