Detect Saltcedar Defoliation Timing at Colorado River in Arizona using dense Landsat Time Series
Yilun Zhao, University of Illinois Urbana-Champaign, yilun3@illinois.edu (Presenter)
Chunyuan Diao, University of Illinois Urbana-Champaign, chunyuan@illinois.edu
Saltcedar (Tamarix spp.) has become a pervasive invasive plant throughout the southwestern United States. As it has spread into the wild, this plant has led to decreased soil evapotranspiration and increased water consumption, soil salinity, fire risks, floods, and erosion in numerous southwestern states. To control saltcedar populations, the tamarisk beetle (Diorhabda) was introduced as a biocontrol species in the United States, with releases occurring between 2001 and 2010. However, the effectiveness of this biocontrol method has varied across different sites, as indicated by numerous studies. Accurate monitoring of saltcedar defoliation is essential for managing invasive plant populations and restoring local ecosystems. Landsat data, which is freely accessible, holds significant potential for detecting subtle land cover changes through long-term observations. With dense Landsat time series, we employ the COntinuous Monitoring of Land Disturbance (COLD) model to detect the timing of saltcedar defoliation at 332 tamarisk beetle observation sites along the Colorado River in Arizona. This region has experienced significant saltcedar invasion, with extensive efforts made to control the invasive plant through multiple tamarisk beetle releases during the biocontrol program. Our results reveal that at 75.9% of the tamarisk beetle observation sites, saltcedar defoliation occurred within five years after, or two years before initial tamarisk beetle observations. The majority of saltcedar plants were defoliated either in the same year (24.1%) or within three years (40.4%) of beetle observations. The identified defoliation timings offer crucial insights into the success of the biocontrol program and provide valuable information to support ongoing saltcedar monitoring, management, and control efforts.
Associated Project(s):
Poster Location ID: 2-47
Presentation Type: Poster
Session: Poster Session 2
Session Date: Wed (May 10) 5:15-7:15 PM
CCE Program: BDEC