Floodplain ecohydrology: Discerning climatic v. anthropogenic controls from tree-ring δ 18 O, dendrochronology, and instrumental climate records

摘要: Vegetation of lowland riparian zones in temperate climates is largely determined by floodplain water availability during the growth season. Floodplain water reservoirs are replenished seasonally by lateral hyporheic water from streamflow, which primarily contributes to phreatic zone water and by infiltration of precipitation, which typically controls seasonal vadose zone soil moisture. Water availability to species rooted to particular depths in the floodplain is subject to interannual variability in climate (eg, precipitation magnitude, timing, and phase). Co-occurring tree species in the riparian zone may express differential adaptation to water availability and shifting water sources, especially if they are rooted at contrasting depths. We have developed an ecohydrologic approach to assess how climatic variability impacts water availability at different depths in the floodplain and corresponding tree growth in the Rhône River …