Changes in Soil Salinity and Plant Diversity After Tamarisk Removal: Seventeen Years of Monitoring by Undergraduate Students

Changes in Soil Salinity and Plant Diversity After Tamarisk Removal: Seventeen Years of Monitoring by Undergraduate Students 

Deborah Kennard^1*

¹Colorado Mesa University, Grand Junction, Colorado, USA

Many studies have documented the benefits of tamarisk (Tamarix spp.) removal for native plant species and other ecosystem features, however fewer studies monitor treated sites annually over extended periods. By integrating ecological monitoring into undergraduate education, we accumulated a long-term data set that reveals annual fluctuations in soil salinity and plant diversity over a 17-year period. This project was primarily initiated to engage undergraduates at Colorado Mesa University (CMU) in the scientific method. Since 2006, classes have measured soil conductivity (an indicator of soil salinity) and plant diversity along a stream draining Devil’s Canyon in McInnis Canyons National Conservation Area. This timeline includes several years of data collected before tamarisk was removed by the Tamarisk Coalition (now RiversEdge West) that provides important baseline site conditions. While the results do confirm that tamarisk removal can significantly increase plant diversity and decrease soil salinity, they also show substantial interannual fluctuations in these parameters. This annual variability has important implications for interpreting short-term or single-year monitoring results. In addition to the scientific value of this study, we found the project provided a compelling laboratory to engage undergraduates in science, invasive management, and riparian restoration. In recent years, this model of incorporating research experiences into undergraduate curricula has become more formally recognized as CUREs or Course-based Undergraduate Research Experiences. A growing body of educational research has demonstrated CUREs to be highly effective at engaging students, particularly historically underrepresented student populations. We encourage other institutions to develop CUREs that could help build larger and longer datasets on restoration projects.