Chemical load: emerging filter in the Community Assembly Theory for ecological restoration in agricultural landscapes

Community Assembly Theory is a framework used to describe the filtering effects of abiotic and biotic conditions on dispersing organisms from regional species pools into local communities. This framework applies well to ecological restoration because abiotic and biotic conditions can be manipulated to achieve restoration outcomes. However, a third filter (chemical load) needs to be considered, especially when restoration is occurring around agriculture. Chemical load consists of herbicide present on a site from prior agricultural practices, herbicide drift from adjacent areas, or on‐site use during restoration. However, herbicide is one of the primary management tools used to manage invasive plant species in agriculture and at restoration sites. A multi‐herbicide analysis was conducted on soils collected from restoration sites in west‐central Minnesota, United States, and results indicated that all samples contained residue from multiple past herbicide applications, illustrating the chemical load present on the landscape.