Detecting the fingerprints of complex land management practices in a tallgrass prairie site using phenocam and satellite images, and the eddy covariance technique

Authors: ZHOU, YUTING - University Of Oklahoma; XIAO, XIANGMING - University Of Oklahoma; Wagle, Pradeep; BAJGAIN, RAJEN - University Of Oklahoma; MAHAN, HAYDEN - University Of Oklahoma; BASARA, JEFFREY - University Of Oklahoma; DONG, JINWEI - University Of Oklahoma; QIN, YUANWEI - University Of Oklahoma; ZHANG, GELI - University Of Oklahoma; LUO, YIQI - University Of Oklahoma; Steiner, Jean; Gowda, Prasanna; Neel, James

Submitted to: Annual American Geophysical Union Hydrology Days
Publication Type: Abstract Only
Publication Acceptance Date: 8/15/2016
Publication Date: 12/12/2016
Citation: Zhou, Y., Xiao, X., Wagle, P., Bajgain, R., Mahan, H., Basara, J., Dong, J., Qin, Y., Zhang, G., Luo, Y., Steiner, J.L., Gowda, P., Neel, J.P. 2016. Detecting the fingerprints of complex land management practices in a tallgrass prairie site using phenocam and satellite images, and the eddy covariance technique [abstract]. American Geophysical Union, December 12-16, 2016, San Francisco, California. Available: https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/157894.

Interpretive Summary: Abstract only.

Technical Abstract: Burning, grazing, and baling (hay harvesting) are common management practices for tallgrass prairie. However, the impacts of these management practices on grassland phenology and carbon uptake are not well understood. Utilizing multiple observations to detect fingerprints of various management practices on phenology and carbon uptake is important to develop and adopt sustainable management practices. In this study, we used canopy greenness (green chromatic coordinate, GCC) extracted from PhenoCam images, vegetation indices (VIs) extracted from satellite images (Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS)), and eddy covariance data to investigate the impacts of burning, an intensive field campaign, baling, and grazing on phenology and carbon uptake in a tallgrass prairie site in El Reno, Oklahoma. Landsat images were used to assess the baling area and the trajectory of vegetation recovery. The MODIS-derived VIs were used in a satellite-based Vegetation Photosynthesis Model (VPM) to simulate gross primary production (GPPVPM) at the flux tower (baled) site. For comparison, we substituted VIs of the flux tower located pixel with VIs from a neighbor pixel (unbaled) and simulated GPP. GCC values showed two peaks with similar magnitude because of quick recovery of grassland after baling. VIs and GPPVPM values showed that the grassland recovered in one month after field campaign and baling. The GPPVPM matched well (R2 = 0.89) with the eddy covariance-derived GPP (GPPEC). The reduction in GPP after baling was compensated by higher GPP after rain pulses in late July and early September, causing little differences in GPP between the baled and unbaled conditions (-0.002 g C m-2 day-1). Our results show that different management practices and their interactions with climate make it complicated to understand the impacts of different land management practices on carbon dynamics and phenology of grasslands. Thus, it is necessary to further investigate the responses of tallgrass prairie ecosystem to both individual and compounded land management practices under different climate.