Water relations of obligate riparian plants as a function of streamflow diversion on the Bishop Creek watershed

摘要

We investigated the water relations of obli-gate riparian plants on paired diverted and undiverted reaches on Bishop Creek, Eastern Sierra Nevada. Ri-parian plants on diverted reaches had reduced stomatal conductance and water potential compared to plants on undiverted reaches in a dry year, but not in a high runoff year. Juvenile plants on diverted reaches had reduced stomatal conductance and lower midday water potentials relative to surrounding mature trees, a trend that was not observed on undiverted reaches. Plants on diverted reaches possessed significantly smaller, thicker leaves and a reduced total leaf area relative to trees on streamside reaches. Reduced community leaf area and effective stomatal control of water loss may allow ripar-ian corridors on diverted reaches to retain their canopies in low runoff years. However, a long term consequence of partial streamflow diversion may be selective mortal-ty of juvenile plants because of the elimination of floods and high flows.