Observations of Ecosystem CO2 Exchanges in a Montane Meadow in Northern Sierra Nevada, California
Abstract
Montane meadows contain complex ecosystems that respond to changing hydroclimate and geomorphic conditions that impact water table depth. Meadow ecosystems in the northern Sierra Nevada may include xeric (sagebrush), mesic (grass and forb) and hydric (sedge and rush) plant communities. Previous research found healthy, wet meadows could sequester considerable amounts of carbon annually, and that daily rates were closely related to soil water availability. However, observations from different meadows in different hydroclimate years are few. Our research objectives are to 1) provide a longitudinal record of carbon cycling in a meadow during restoration, and 2) understand the relative contributions of different meadow plant communities. We present the broader project design and results from the first growing season in a meadow located in the north-eastern Sierra Nevada, California, USA. We installed an eddy covariance system to measure net ecosystem exchange of CO2. The tower was located near the boundary between xeric and mesic regions of the meadow, allowing comparison of CO2 exchanges between the two plant communities. The mesic community sequestered over 12 gC m-2 d-1 during peak growth, which was 63% higher than the xeric community. To investigate the relative contributions of individual plant alliances, a manual chamber system was developed using a 0.42 m3 clear chamber enclosing a 0.56 m2 surface, measuring CO2 and H2O exchanges, PAR, temperature, soil moisture and LAI. We sampled each of the major plant alliances during the 2019 growing season. Preliminary analysis of chamber results suggests CO2 uptake of the hydric plants was significantly greater than the xeric plants while mesic plants did not differentiate significantly from either hydric or xeric plant groups. Taken together, our results show that meadow-scale carbon sequestration rates depend on plant community distribution and soil water availability.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMEP51E2149M
- Keywords:
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- 1824 Geomorphology: general;
- HYDROLOGY;
- 1825 Geomorphology: fluvial;
- HYDROLOGY;
- 1830 Groundwater/surface water interaction;
- HYDROLOGY;
- 1856 River channels;
- HYDROLOGY