Date of this Version
There has been a variety of wetland monitoring projects implemented in playa wetlands in Nebraska over the last decades. But there is still a lack of continuous wetland monitoring on long-term and large-area dimension. Because inundation condition is one of the critical parameters to describe wetland hydrologic performance, this study aims to assess the inundation alteration in playa wetlands in Nebraska and evaluate the performance of wetland conservation and restoration practices. This study uses the Landsat data to create playa wetland inundation condition maps and analyze the variation trend of inundated playa wetlands over the past 30 years. The results show that the total inundated areas from 1985 to 2015 were 220.63 km2, which represents 23.61% of total area of playa wetlands. And 9,898 wetlands, representing 29.41% of total 33,659 historical wetlands, were identified as functional wetlands. The findings confirm that agricultural activities have significantly altered and degenerated the natural hydrology in playa wetlands and wetland conservation and restoration practices are crucial to protect and recover functional playa wetlands.
This study also aims to improve the effectiveness of restoration programs for the variable aspects of wetlands in playa wetlands by prioritizing the variable restoration practices. The process includes discussing the primary threats and frequently used wetland restoration methods and identifying the principles to choose the proper restoration methods. The results identifies the most prioritized practices, including the full hydrologic restoration, partial hydrologic restoration, and vegetative restoration; and less prioritized practices, including wetland enhancement and wetland establishment. Overall, wetland restoration needs a comprehensive package of restoration methods. Any single restoration method or restoration program cannot alleviate threats that wetlands faced. The long-term restoration strategies with comprehensive methods are needed for playa wetlands.
Advisor: Zhenghong Tang
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