Will ephemeral wetlands be impacted by changing climate and land use in the Southern High Plains?

Authors: OWEN, RACHEL - University Of Missouri; GOYNE, KEITH - University Of Missouri; WEBB, ELISABETH - Us Geological Survey (USGS); Veum, Kristen

Submitted to: Soil Science Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 12/6/2018
Publication Date: 1/6/2019
Citation: Owen, R.K., Goyne, K.W., Webb, E.B., Veum, K.S. 2019. Will ephemeral wetlands be impacted by changing climate and land use in the Southern High Plains? [abstract]. Soil Science Society of America International Meeting, January 6-9, 2019, San Diego, California. Paper 115816.

Interpretive Summary:

Technical Abstract: Great Plains playas are shallow, recharge wetlands that provide many essential ecosystem functions; however, projected precipitation changes over the next century have potential to influence these ecosystem services. We conducted controlled mesocosm experiments to quantify effects of predicted precipitation change on wetland biogeochemical cycles in Nebraska and Texas playas, predominantly examining various forms of carbon (C) and nitrogen (N), as well as plant-available phosphorus (Bray P-1). We monitored soil organic carbon (TOC) and nitrogen (TON), nitrate (NO3-), and ammonia (NH4+) monthly during a six-month greenhouse experiment, and subsequently conducted an incubation experiment to measure carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions under aerobic and anaerobic conditions. Soil microbial communities were assessed using phospholipid fatty acid (PLFA) methods and analyzed using non-metric multidimensional scaling techniques. Soil TOC and TON were negatively correlated with bulk density (p < 0.001) and positively correlated with soil moisture (p < 0.001), but no significant trends were associated with climate treatments (R2=0.273). Bray P-1 was positively correlated with bulk density. Under aerobic and anaerobic conditions, CO2 emissions did not vary by precipitation treatment. However, CH4 emissions varied for Texas samples during aerobic study and for Nebraska and Texas samples during anaerobic study. Soil microbial communities did not cluster based on precipitation treatments, but were also not predominantly dependent upon random variation between sampling sites. Results indicate that playa hydroperiod and soil moisture impact soil C and N biogeochemical cycles to varying extents, however, microbial communities may be well adapted to rapidly changing hydrologic conditions in playas, driving a consistent response for biogeochemical responses in historic and future climate conditions. Soil management strategies that increase soil moisture and reduce soil bulk density may promote C and N sequestration under current and future precipitation regimes across the spatial range of playas.