2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/26/2021 | 8:30 AM - 10:30 AM | DIRECT AND INDIRECT EFFECTS OF RIPARIAN WOODY PLANT EXPANSION ON NITROGEN CYCLING IN GRASSLAND STREAMS AND RIPARIAN SOILS | Virtual Platform
DIRECT AND INDIRECT EFFECTS OF RIPARIAN WOODY PLANT EXPANSION ON NITROGEN CYCLING IN GRASSLAND STREAMS AND RIPARIAN SOILS
Low-order grassland streams were historically open canopy systems, but this is changing worldwide due to woody plant expansion. Soil carbon and nitrogen stocks increase with woody expansion and it is unclear how these changes in riparian soils influence stream biogeochemistry. We measured rates of nitrification and denitrification in open and closed canopy streams and adjacent riparian soils to examine benthic and riparian nitrogen dynamics. We used path analysis to test hypotheses regarding direct and indirect effects of riparian woody plants on nitrification and denitrification. Stream surveys showed reaches dominated by woody plants exhibited structural changes seasonally; the proportion of epilithic biofilm cover was 48% lower in closed canopy reaches during the fall, while cover by coarse particulate organic matter was 61% higher. Path analyses suggest woody expansion directly influences riparian nitrification, and there are indirect effects on denitrification mediated by soil carbon and nitrate concentrations. Furthermore, woody plants indirectly affect benthic denitrification by influencing nitrate concentration in streams. We highlight that woody expansion may alter carbon and nitrogen dynamics in grassland streams. Future research should focus on specific mechanisms of the impact of riparian woody plant expansion on stream biogeochemistry.
- Ecotones
- Nutrient cycling
- Resource subsidies
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Presenters/Authors
James Guinnip
(), Kansas State University, jguinnip@ksu.edu;
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Walter Dodds
(), Kansas State University, wkdodds@ksu.edu;
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