Assessing Salinity Dynamics of Saline Wetlands in Eastern Nebraska Using Continuous Data from Wireless Sensors

Abstract

The salinity level is the most important characteristic of saline wetlands. Monitoring the salinity dynamics can provide timely and accurate information for saline wetland conservation decision-making. Conducting high-frequency measurements of electrical conductivity in the topsoil and surface water can generate continuous data that enables the understanding of the changes in salinity conditions spatially and temporally. In this research, during 2021–2022, the conductivity of surface water and topsoil was measured in six selected saline wetlands located in eastern Nebraska using the HYDRO 21 and TEROS 12 sensors. Despite significant variations among the six sites, the findings indicate a relatively high level of topsoil salinity in five wetlands sites. The mean bulk electrical conductivity (ECb) of the topsoil across all six locations was 17.63 dS/m, with a standard deviation of 11.58 dS/m. The upstream wetland in the Salt Creek West Wildlife Management Area (WMA) had the highest soil salinity level, with an ECb of 31.61 dS/m and a standard deviation of 8.64 dS/m. During a significant inundation event in 2021, the EC of the surface water measured 0.22 mS/cm, with a standard deviation of 0.18 mS/cm. The findings of this study have found evidence supporting the effectiveness of a conservation program in maintaining the relatively salty status of topsoil. Moreover, the fact that surface water salinity levels are relatively low indicates that saline wetland ecosystems are facing ongoing degradation challenges. Based on the findings, it suggests that hydrological restoration at the watershed level is crucial for the conservation of saline wetland systems. Salinity levels greatly influence saline wetlands, making it crucial to monitor and understand the changes in salinity for effective conservation decision-making. This research focused on measuring salinity dynamics in six selected saline wetlands in eastern Nebraska between 2021 and 2022. High-frequency measurements of electrical conductivity in topsoil and surface water were performed using specialized sensors. By collecting and analyzing the data from these sensors, the study aimed to better understand how salinity levels fluctuate over time. The findings revealed significant variations among the wetland sites, with five sites exhibiting relatively high levels of topsoil salinity. The results of this research provide valuable insights into the dynamics of salinity in saline wetlands, offering crucial information for the management and conservation of these unique ecosystems.