GEOMORPHOLOGY AND FLORAL DIVERSITY AT GRAND CANYON ECOREGION SPRINGS

Springs are important resources providing critical sources of water, supporting diverse arrays of endemic life, and significant cultural roles. Springs occupy only a small portion of the landscape yet large number of species in arid regions depend on them. Further, springs are sensitive ecosystems easily impacted by contamination, groundwater pumping, or disturbance. Springs ecosystems have recently received increased attention from land managers attempting to catalog springs resources, restore degraded springs and protect the species that depend on them. Springs vary widely across the landscape based in the biotic communities they support and the controls on biodiversity at springs is not well understood. Efforts to study springs have resulted in a classification system widely adopted and used in spring inventories that includes twelve distinct spheres of discharge describing the geomorphic emergence characteristics of a spring. This study uses a database of springs inventories from the Grand Canyon ecoregion to statistically test several hypotheses. First, we test differences between the four most common springs types. We hypothesize that each sphere of discharge will have distinct geomorphic, physical, and biological differences allowing it to be distinguished. Second, we explore the controls on floral diversity at springs. We hypothesize that geomorphic microhabitat heterogeneity will be positively related to floral diversity.