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Flood pattern and weather determine Populus leaf litter breakdown and nitrogen dynamics on a cold desert floodplain

Journal of Arid Environments

By:
and
https://doi.org/10.1016/j.jaridenv.2005.06.022

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Abstract

Patterns and processes involved in litter breakdown on desert river floodplains are not well understood. We used leafpacks containing Fremont cottonwood (Populus deltoides subsp. wislizenii) leaf litter to investigate the roles of weather and microclimate, flooding (immersion), and macroinvertebrates on litter organic matter (OM) and nitrogen (N) loss on a floodplain in a cool-temperate semi-arid environment (Yampa River, northwestern Colorado, USA). Total mass of N in fresh autumn litter fell by ∼20% over winter and spring, but in most cases there was no further N loss prior to termination of the study after 653 days exposure, including up to 20 days immersion during the spring flood pulse. Final OM mass was 10–40% of initial values. The pattern of OM and N losses suggested most N would be released outside the flood season, when retention within the floodplain would be likely. The exclusion of macroinvertebrates modestly reduced the rate of OM loss (by about 10%) but had no effect on N dynamics over nine months. Immersion in floodwater accelerated OM loss, but modest variation in litter quality did not affect the breakdown rate. These results are consistent with the concept that decomposition on desert floodplains progresses much as does litter processing in desert uplands, but with periodic bouts of processing typical of aquatic environments when litter is inundated by floodwaters. The strong dependence of litter breakdown rate on weather and floods means that climate change or river flow management can easily disrupt floodplain nutrient dynamics.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Flood pattern and weather determine Populus leaf litter breakdown and nitrogen dynamics on a cold desert floodplain
Series title:
Journal of Arid Environments
DOI:
10.1016/j.jaridenv.2005.06.022
Volume:
64
Issue:
4
Year Published:
2006
Language:
English
Publisher:
Elsevier
Contributing office(s):
Fort Collins Science Center
Description:
25 p.
First page:
626
Last page:
650