Public gardens and arboreta across the United States have long served as early warning systems, helping scientists track and assess the damage that invasive pests and shifting climate conditions can inflict on trees and plants. These "sentinel plant systems” are a key player in keeping invasive plants and pests under control and out of North America’s ecosystems. Predicting the future range of native and ornamental plants as the climate is warming up is also a critical component of sentinel plant systems.
Researchers from the Department of Soil, Water, and Climate (SWAC), Minnesota Landscape Arboretum, and the Department of Forest Resources at the University of Minnesota believe these gardens can and should do even more in the fight against invasive species. In a recently authored perspective paper in Frontiers in Forests and Global Change, the researchers call for the inclusion of soil monitoring as a component of established sentinel plant systems. The article suggests the establishment of a soil-plant continuum as an integral part of sentinel plant systems, a model that takes into account the health of the soil as a vital part of the fight against invasive pests.
This recommendation emerged from ongoing research on invasive earthworms- specifically, jumping worms. Unlike typical garden pests that damage leaves or stems, jumping worms fundamentally restructure the soil itself—depleting the spongy layer of organic matter that native plants depend on, altering how soils hold water, and contributing to erosion. Because their damage works belowground, plant-focused monitoring alone can miss the warning signs until it's too late.
Public gardens, such as the University of Minnesota Landscape Arboretum, are uniquely positioned to help. They already host long-term plant collections, trained staff, and strong connections to scientists and local communities. By extending what they observe to include soil health alongside plant health, these institutions could become powerful hubs for detecting ecological change, before it becomes visible on the surface.
“Public gardens are already nature's smoke detectors, sounding the alarm on threats—from invasive pests to shifting climates—before those threats take hold in the wider landscape,” explains SWAC professor and co-author Kyungsoo Yoo. “It’s natural that there should be a consideration for soils.”