Springs as hydrologic refugia in a changing climate? A remote‐sensing approach

• DOI: 10.1002/ecs2.2155
• Publication Date: 2018-04-10T07:55:22Z
• Authors: Jennifer Cartwright; Henry M. Johnson
• Keywords: Snowmelt; Steppe

Abstract Spring‐fed wetlands are ecologically important habitats in arid and semi‐arid regions. Springs have been suggested as possible hydrologic refugia from droughts climate change; however, springs that depend on recent precipitation or snowmelt for recharge may be vulnerable to warming drought intensification. expected maintain their ecohydrologic function a warmer, drier priorities conservation restoration. Identifying such is difficult because many lack records of adequate temporal extent resolution assess resilience water cycle changes. This study demonstrates proof‐of‐concept the assessment certain spring types (i.e., helocrene, hypocrene, hillslope springs) terms ecological climatic stress using freely available remote‐sensing data. We used Normalized Difference Vegetation Index ( NDVI ) 1985 through 2011 delineate surface‐moisture zones SMZ s) associated with 39 clusters 172 montane sage‐steppe landscape southeastern Oregon, USA . developed synthesized seven ‐based indicators interannual changes availability: (1) mean (2) standard deviation July ; (3) difference (4) coefficient variation between each its surrounding watershed; (5) response 90‐day antecedent precipitation; (6) previous winter's snowpack; (7) range values an exceptionally wet year followed by three dry years. Because all were highly inter‐correlated, we derived overall metric principal components analysis accounted 66% total variance. score was positively correlated elevation, slope, annual precipitation, number springs. Resilience greater s topographically shaded, north‐facing slopes. Several high‐resilience located immediately below persistent snowbanks, suggesting source steady throughout growing season. The approach presented here—if combined field assessments hydrogeology, discharge, groundwater age—could help identify spring‐fed most likely serve change.