Botanical Inventory of Plaster Creek

1
Floristic Quality Index For each section of the
creek the floristic quality index (FQI) was
calculated. The Michigan Department of Natural
Resources assigns all plants native to the state
a coefficient of conservatism (CC), a numerical
representation of a species ability to withstand
disturbance. A plant with a CC of ten would
survive only in pristine habitats, while one with
a CC of one would thrive in areas highly
disturbed by weather or human intervention. The
FQI is calculated by multiplying the mean CC by
the square root of the total number of plant taxa
present. Once the FQI has been calculated it can
be used to determine the significance of the
plant diversity at a given site. This is helpful
in planning future development of these sites. An
FQI of less than 20 indicates minimal
significance. Areas with an FQI of 35 or higher
have statewide floristic importance. An area
with an FQI of 50 or higher represents a
significant component of Michigans biodiversity
and natural landscape.
Introduction Plaster Creek flows for about 18
miles from its source through Southeast Grand
Rapids on its way to the Grand River. The
watershed covers a considerable portion of this
area, including the campus of Calvin College. The
creek itself connects rural, residential, urban
and industrial areas, all having experienced
varying degrees of development over the past
several decades. In some sections of the creek, a
wide floodplain provides a considerable buffer
between the creek and the built up environment.
In other areas the flow of the creek has been
dramatically altered leaving little to no buffer
zone. Students from Plant Taxonomy class have
divided the creek into six sections, surveying
the botanical diversity in each section to get a
sense of what plant life is present along its
banks.
Botanical Inventory of Plaster Creek
Historical Significance In 1901, Emma Cole
published Flora of Grand Rapids, highlighting the
botanical features of the region at the turn of
the century. Cole refers to Plaster Creek as an
area of rich botanical value, noting the presence
of Trillium nivale (Snow Trillium, now all but
extinct in Michigan) and several species of
orchids found along the banks. Ken-O-Sha
Park At this time the most preserved area of the
creek runs between 28th Street and Kalamazoo Ave
through Ken-O-Sha park. This area includes oaks
estimated to be over 220 years old. A previous
survey of the area by Dave Warners revealed an
FQI of 56, making it extremely significant. Highl
ighted findings This project has highlighted
several species that are listed by the Michigan
DNR as threatened or of special concern. These
include Diarrhena americana (American Beakgrass
top), Mertensia virginica (Virginia Bluebells,
middle), and Lithospermum latifolium
(Broad-leaved puccoon, bottom).
Noah Kruis and Dave Warners, Calvin College
References Cole, Emma. Flora of Grand Rapids A
Catalogue of the Flowering Plants and Ferns
Growing Without Cultivation in the Vicinity of
Grand Rapids, Michigan. A. Van Dort, Book and Job
Printer. 1901. Herman, Kim D. et. al. Floristic
Quality Assessment with Wetland Categories and
Examples of Computer Applications for the State
of Michigan. Michigan Department of Natural
Resources. 2001.