2023 CSDMS meeting-084
Investigating the importance of rock-fracture water storage for cliff trees using stable isotopes and a stock-flow model
Estefania Roldan Nicolau, (she/her),University of Calgary Calgary , Canada. email@example.com
Jose Palacios, No affiliation Calgary, Alberta , Canada. firstname.lastname@example.org
Michelle Ives, University of Calgary Calgary, Alberta , Canada. email@example.com
Edward A. Johnson, University of Calgary Calgary, Alberta , Canada. firstname.lastname@example.org
In terrestrial ecosystems, rock fractures as unsaturated reservoirs for vegetation have been recently recognized as a key ecohydrological process. However, it remains unclear how the coupling between plant water use strategies and rock water storage interplay. We selected Douglas fir and Engelmann spruce trees growing on both soils and exposed limestone cliffs in the Canadian Rockies. We measured sap flow, stem water potential, and superficial fracture substrate moisture for trees growing in rock fractures and glacial till. Isotopic analysis of precipitation, plants, and soil samples revealed that the trees do not have access to any long-term water sources but rather use recent precipitation values. To explore the relationship within the system, we built a stock-flow model with three stocks: the surface fracture, the deep fracture, and the tree itself, and observed that cliff trees respond slightly differently to water replenishment due to the cliff architecture. Plant regulation coupled with rock water storage is crucial to model water movement through plants in highly water-limited environments correctly. Our study highlights the importance of understanding how trees access rock moisture storage in water-limited environments.