INFLUENCE OF SPRINGS WATER GEOCHEMISTRY ON GEOMORPHOLOGY AND VEGETATION COVER AT SPRINGS ECOSYSTEMS

Springs ecosystems support diverse and unique biological communities often threatened by development and excessive groundwater pumping. Few hydrogeologic studies have focused on the relation between the geochemical properties, the geomorphology and vegetation cover at springs ecosystems. Understanding the feedbacks between abiotic and biotic factors in springs ecosystems has significant implications for species protection and ecosystem management. Water chemistry influences vegetation type, while vegetation controls the chemical properties of the spring. Furthermore, vegetation change shapes local geomorphology by adjusting erosion rates and channel morphology. Using the extensive Springs Inventory Database of the Springs Stewardship Institute, we determined the connections between vegetation cover, water chemistry, and geomorphology of springs. The springs ecosystems of the Spring Mountains National Recreation Area of southern Nevada were used to ground-truth preliminary conclusions and test our methodology.

Local and regional groundwater flow systems can be delineated isotopically. The concentrations of hydrogen and oxygen isotopes of emerging groundwater are influenced by travel time and the source of infiltration from meteoric water. Local flow systems have similar vegetation based on related aquifer geochemical properties, as well as analogous geomorphic characteristics due to similar water transport mechanisms. The emergence zones of regional flow systems, however, vary considerably in both vegetation cover and geomorphology because of the variety of groundwater recharge sources and long distance flow paths. These results are preliminary, and more springs need to be analyzed to confirm these interpretations.