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Characterizing flow regimes for floodplain forest conservation: An assessment of factors affecting sapling growth and survivorship on three cold desert rivers

Canadian Journal of Forest Research

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https://doi.org/10.1139/x05-203

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Abstract

I analyzed annual height growth and survivorship of Fremont cottonwood (Populus fremontii S. Watson) saplings on three floodplains in Colorado and Utah to assess responses to interannual variation in flow regime and summer precipitation. Mammal exclosures, supplemented with an insecticide treatment at one site, were used to assess flow regime – herbivore interactions. Multiple regression analyses on data collected over 7–11 years indicated that growth of continuously injury-free saplings was positively related to either peak discharge or the maximum 30-day discharge but was not related to interannual decline in the late-summer river stage (ΔWMIN) or precipitation. Growth was fastest where ΔWMIN was smallest and depth to the late-summer water table moderate (≤1.5 m). Survivorship increased with ΔWMIN where the water table was at shallow depths. Herbivory reduced long-term height growth and survivorship by up to 60% and 50%, respectively. The results support the concept that flow history and environmental context determine whether a particular flow will have a net positive or negative influence on growth and survivorship and suggest that the flow regime that best promotes sapling growth and survival along managed rivers features a short spring flood pulse and constant base flow, with no interannual variation in the hydrograph. Because environmental contexts vary, interannual variation may be necessary for best overall stand performance.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Characterizing flow regimes for floodplain forest conservation: An assessment of factors affecting sapling growth and survivorship on three cold desert rivers
Series title:
Canadian Journal of Forest Research
DOI:
10.1139/x05-203
Volume:
35
Issue:
12
Year Published:
2005
Language:
English
Publisher:
NRC Research Press
Contributing office(s):
Fort Collins Science Center
Description:
14 p.
First page:
2886
Last page:
2899