Survey Success: Better for Butterflies

According to the latest Natural Areas Assessment survey conducted by Friends this summer, overall native plant coverage increased to nearly 70 percent at the 14 targeted work sites that comprise the survey, impacting over 400 acres- the highest percentage total since monitoring began in 2016. Native plants are the foundation of a healthy ecosystem and provide a wide array of benefits to support native wildlife all of kinds and in improving water quality. The assessment also found sustained improvements in plant quality and diversity over the five year period at all sites. Although we have not assessed them yet, Friends expects the same positive change at the sites we've restored, Crooked Creek and Mill Creek, and in new efforts planned for 2021 and 2022.

Since the Natural Areas Assessment began Friends has tracked a 75% decrease in invasive buckthorn at the 14 locations. Six of the sites are in northern Cook County, three are in Chicago, and five are in southern Cook County. All are along the river system.

"The plant quality data gathered over the past five years supports what we see just walking through the sites; overall increases in plant quality and native coverage are very evident," said Mark Hauser, ecology outreach manager at Friends of the Chicago River. "The sites are no longer choked with buckthorn; they are healthier. This is a testament to everybody's hard work including and especially stewards and volunteers."

Friends conducts the annual survey to measure the ongoing impact of our large-scale landscape restoration efforts and volunteer-based stewardship in conjunction with our partners at the Forest Preserves of Cook County, Friends of the Forest Preserves, and the Chicago Park District. The survey utilizes a plant-based metric called a Floristic Quality Assessment Index (FQI) to measure the ecological condition or quality of a plant community.

 The improvements at the volunteer sites are the result of the work of hundreds of corporate volunteers who participated in River Action Days and thousands of Centennial Volunteers who remove invasive species and spread native seeds.

However, there is still much to be done, and other lesser-known non-native species such as Canada thistle, sweet clover and amur honeysuckle are creeping in where pervasive buckthorn once dominated. The restoration process requires ongoing maintenance and is dependent upon partnerships and volunteer support.