After beetles were released in 2001 to control tamarisk, predicted flycatcher habitat along the lower Virgin River fell 94.2% between 2010 and 2015

In 2001, the U.S. Department of Agriculture released tamarisk leaf beetles in an effort to control an invasive plant along the lower Virgin River in Nevada and Arizona. The beetles were introduced to eat tamarisk, a non-native bush that had taken over riparian areas throughout the West. The primary concern, however, was the impact on the Southwestern willow flycatcher, an endangered songbird that nests in the tamarisk.

Between 2010 and 2015, predicted flycatcher habitat along the lower Virgin River fell 94.2%, with 5.8% remaining. The U.S. Geological Survey model, using Landsat satellite images and habitat models, found that the habitat time series did not show the effects of beetles until 2011. From 2013 to 2015, the average predicted flycatcher habitat plummeted to 88 hectares, about 12.6% of the historical average.

The largest habitat losses occurred in the zone nearest Lake Mead National Recreation Area, which saw a 99.6% reduction in predicted habitat by 2015. Losses varied across the river, with some areas gaining habitat from a baseline of less than one hectare. While the simulation tool cannot predict which patches of land the birds will use each year, the larger implication extends beyond the flycatcher. The study suggests that areas with more native species will experience less destruction.