Gerould Wilhelm Ph.D.
Principal Botanist/Ecologist


Biographical Narrative by James Patchett

When I first met Jerry in the late 1980’s, I was already familiar with his reputation as a foremost botanist, research taxonomist, and educator. He co-authored, through years of collaboration at the Morton Arboretum in Lisle, Illinois, the definitive text “Plants of the Chicago Region” with the late Floyd Swink. It was only after we became friends and colleagues shortly thereafter that I learned the depth of his botanical knowledge which is nothing short of world-class. Simply put, Jerry has an extensive knowledge of the flora of North America and the world, and he combines that understanding with other skills that, in my opinion, set him apart in the field of applied ecology and sustainable design.

I consider myself very fortunate over the past several decades to have met and collaborated with some of the most respected ecologists in the country. With that said, Jerry possesses the most comprehensive understanding of the physical and cultural evolution, context, and function of North American ecosystems of anyone that I have ever met. It is this depth of understanding that I consider his most vital attribute, along with a genuine openness to new ideas, dialogue, and creativity that is somewhat rare in a field where traditionally trained botanists and ecologists are often deeply embedded in conventional scientific doctrine.

It was Jerry, who after years of disciplined field research and observation first exposed me to the basic understanding of historical hydrological processes where the relationship between terrestrial and aquatic ecosystems was dominated by infiltration, groundwater movement, and discharge. Once I grasped the basic truth of these principles, I had my own professional epiphany. It became remarkably clear the degree to which many conventional urban, suburban, and rural agricultural land use practices are both economically and ecologically unsustainable, and how traditional stormwater engineering methods literally undermine the physical integrity of our ecosystems.

Jerry is also noted for his development of the Floristic Quality Assessment (FQA) methodology, which to our knowledge is the only repeatable, consistent quantitative measure available for the determination of floristic habitat quality. The FQA was originally developed for the geographic coverage of the “Plants of the Chicago Region”, but has continued to become far more widely adapted to currently include the states of Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, New Jersey, North and South Dakota, Wisconsin, and parts of Florida, Pennsylvania, and southern Ontario.

Jerry’s latest research effort, the report and output of which can be accessed from our website under the heading of “Resources: Timber Hill Savana Final Report” (Download the PDF), further illustrates the shortcomings in contemporary ecological doctrine pertaining to such spurious notions as plant community succession. This study forms the basis for an increased understanding and awareness of the critical cultural relationships involved in the evolution of North American landscapes and ecosystems.


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Gerould Wilhelm

(630) 640-1402



Southern Illinois University

Ph.D. Botany, 1984

Dissertation: Vascular Plants of the Pensacola Region


Florida State University

B.S. Biology, Minor in Chemistry, 1971


Publications (partial list)

 Special Vegetation of the Indiana Dunes National Lakeshore. The National Park Service. 1990


Invention and development of the Floristic Quality Assessment


Vascular Flora of the Pensacola Region. University Microfilms. 1984


The Lichen Flora of Chicago and Vicinity: One Hundered Years of Lichenology. Eriginia. 1998


Plants of the Chicago Region 4th ed. Indiana Academy of Sciences. 1994


Fate and effects of contaminants in ecosystems: plant communities. Application and Interpretation of Bioassay and Biomonitoring: A Planning Document. 1987


Professional Affiliations

Michigan Technical Committee on Endangered and Threatened Species


Illinois Native Plant Society


DuPage County Environmental Commission


Indiana Academy of Science


Chicago Wilderness Society Team, Chicago Region


Society of Ecological Restoration, Past Board Member


Sigma Xi, The Scientific Research Society


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