Journal article
Watershed Alnus cover alters N:P stoichiometry and intensifies P limitation in subarctic streams
Biogeochemistry, Vol.153(2), pp.155-176
03/19/2021
DOI: 10.1007/s10533-021-00776-w
Abstract
In many watersheds, nitrogen (N)-fixing alder (
Alnus
spp.) provides key nutrient subsidies to terrestrial and aquatic ecosystems. The importance of these subsidies may increase as alder cover expands under climate warming at high latitudes. We assessed how landscape features and meteorological conditions affect aquatic N and phosphorus (P) availability and stoichiometry in 26 streams across natural gradients of alder cover in southwestern Alaska over the spring and summer, covering 4 years. Analyses of resin lysimeter samples from select watersheds showed that annually, soils under alder leached almost three times more N, and two times more P than under non-alder vegetation. Stream NO
3
−
concentrations displayed a non-linear relationship with alder cover; NO
3
−
was low where alder cover was < 30%, but increased markedly where alder cover was > 30%. Watershed elevation was inversely related to alder cover, stream NO
3
−
concentrations, and stream NO
3
−
yields. Dissolved and particulate stream P were unrelated to alder cover, watershed elevation or discharge, highlighting decoupling of controls on P between terrestrial and aquatic ecosystems. Snowmelt-associated nutrient pulses and hydrology likely resulted in greater stream N and P in the spring, compared to the summer. However, weather parameters only impacted stream N via their interaction with alder. Stream DIN:TP increased with alder cover and decreased with elevation, suggesting that alder intensified P-limitation. Hence, aquatic P-limitation may become increasingly pronounced as climate-induced alder expansion continues. These results demonstrate that the elevational gradient in watershed alder cover determined spatial patterns in stream N availability and nutrient limitation.
Details
- Title: Subtitle
- Watershed Alnus cover alters N:P stoichiometry and intensifies P limitation in subarctic streams
- Creators
- Denise A Devotta - Program in Ecology, Evolution, and Conservation Biology, University of IllinoisJennifer M Fraterrigo - Program in Ecology, Evolution, and Conservation Biology, University of Illinois, Department of Natural Resources and Environmental Sciences, University of IllinoisPatrick B Walsh - Togiak National Wildlife Refuge, U.S. Fish and Wildlife ServiceStacey Lowe - Eastern Shore of Virginia National Wildlife Refuge, U.S. Fish and Wildlife ServiceDaniel K Sewell - College of Public Health, University of IowaDaniel E Schindler - School of Aquatic and Fishery Sciences, University of WashingtonFeng Sheng Hu - Program in Ecology, Evolution, and Conservation Biology, University of Illinois, Department of Plant Biology, Department of Geology, University of Illinois, Department of Biology, Washington University, Department of Earth and Planetary Sciences, Washington University
- Resource Type
- Journal article
- Publication Details
- Biogeochemistry, Vol.153(2), pp.155-176
- Publisher
- Springer International Publishing
- DOI
- 10.1007/s10533-021-00776-w
- ISSN
- 0168-2563
- eISSN
- 1573-515X
- Grant note
- U.S. Fish and Wildlife Service (http://dx.doi.org/10.13039/100000202)
- Language
- English
- Date published
- 03/19/2021
- Academic Unit
- Biostatistics; Public Policy Center (Archive)
- Record Identifier
- 9984214948002771
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