Biological Invasions


Aggressive non-native plants quickly choke out native plants and, in turn, drive out animals that rely on the native plants for everything from food to reproduction. The primary invader in the Calumet area is the purple loosestrife.


Often called the "purple plague" it is native to Europe and Asia. Purple loosestrife showed up in Canada about 50 years ago and quickly spread to the U.S. Its vivid purple flowers plague much of Illinois’ wetland areas, where it displaces marsh grasses, rushes, cattails, reeds and orchids, and forms an impenetrable hedge. The yellow-headed blackbird, an endangered native species, needs the stiff stems of native plants to support its nest. When the plants disappear, so does the bird.


Purple Loosestrife - Beautiful but poison to our native wetlands.

Destructive Development


In recent years, high quality natural areas have been compromised by inappropriate activities on public lands in the region. For example, part of the northwest corner of Lake Calumet, estimated to be in excess of 10 acres, was filled in by the Illinois International Port District to create a golf course. In 1996, a gas company completely destroyed a large tract of high quality prairie in order to inspect a gas pipe line that runs underground. Local volunteers had been restoring Powderhorn Prairie for over 10 years.


Shores of Lake Calumet bulldozed for development.



Contamination from abandoned industrial sites, hazardous waste dumps and landfills continues to be a threat to the surrounding natural areas. Pollution from these sites runs off into the surface waters of Lake Calumet and its surrounding rivers and wetlands. Contaminated groundwater is linked to surface waters used by wildlife. It is very likely that the entire aquatic system is linked to Lake Michigan, a drinking water source for millions of people.


Any effort to conserve biodiversity and quality habitat in the region must acknowledge threats from past and present contamination from industrial and waste disposal activities. Abandoned sites must be cleaned up and the affects on the Lake from pollution must be identified and dealt with.


A legacy of pollution from decades of heavy industry.