Common butterwort (Pinguicula vulgaris L.) is a carnivorous
member of one of five genera of the Lentibulariaceae, the family which
also includes the bladderworts (Utricularia). In Northeastern
North America the genus is represented by only P. vulgaris,
though there are approximately 35 species worldwide, distributed in
from Arctic to temperate regions of the Northern Hemisphere and in
the Andes (Lloyd, 1942; Gleason and Cronquist, 1991).
P. vulgaris is distributed circumboreal in North America and
Eurasia, with a gap in distribution in north-central Siberia; a distribution
map is given in Hultòn's Amphi-Atlantic Plants (1958).
The plant grows normally in Boreal and Arctic regions, with a more
southerly distribution in North America to the northern Great Lakes-St.
Lawrence region and the Maritime areas of Canada. It reaches
its southern limit in the Great Lakes region along the shores of Lakes
Michigan and Huron on Beaver Island and the northern lower peninsula
Site of Study:
Beaver Island is located in the northeastern Lake Michigan,
in Charlevoix County, Michigan. On Beaver Island, there
are only two known locations of Pinguicula, indicated on the map is
shown in figure 1. As referred to in this study, site
1 is the northern Donnegal Bay area, on the northwest side of the
island, and site 2 is located on the northeast side of the island.
These two sites are located close to the shoreline, in swales between
the beach area and the forest edge. Typical swale vegetation
such as Carex spp., Potentilla anserina, Tofeldia
glutinosa, Thuja occidentalis, Castelleja coccinea,
Equisetum spp, Juncus balticus, Larix laricina,
Parnassia glauca, Primula mistassinica, Rhyncospora
alba, Picea glauca, and others were typical at both sites.
In addition, site 1, Donnegal Bay, has large populations of the canioverous
plants Drosera linearis and D. rotundifolia, as well
as apparently declining population of Sarracenia purpurea.
Though other, similar habitats exist on Beaver Island, the two sites
remain the only known occurrences on Beaver Island.
Purpose of Study:
The purpose of this paper and the research project is to begin
a long-term monitoring of the demographic conditions of the two known
areas of Pinguicula on Beaver Island via continued examination
of "representative" quadrats. Financial and time restrictions
during the 1994 study limited the study to four quadrats, two at each
site. Another purpose of the study in 1994 was to examine
the spatial and size variations present in the Pinguicula communities.
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The two communities of Pinguicula vulgaris on Beaver
Island are worthy of continued monitoring. This will contribute
further understanding not only of the general ecology and demographic
characteristics of P. vulgaris, but the local state of plants and
communities present on Beaver Island, an area under increasing development
pressure for vacation and retirement homes, as well as tourism-related
industries. Though site 2, Little Sandy Bay, has recently
been purchased by a Michigan conservancy group, and therefore is assumed
relatively free from the threat of development, the future of site
1, Donnegal Bay, is uncertain. There has been an increased
amount of home construction along the shoreline on Beaver Island in
recent years, particularly along the areas on the northwest of the
island. Numerous new surveying and planning signs were
observed in the immediate area of site 1, and even if the exact site
of Pinguicula communities is not built upon, the risk of substantial
degradation of the communities is present. Degradation
is a threat to these fragile plants from disturbances such as foot
and vehicle traffic, alien species introduction, landscaping changes
by new residents, and other human-related factors. At
the the Little Sandy Bay site, motorized vehicle degradation was seen
clearly, from small recreational-utility vehicles and passenger vehicles,
was seen in several areas along the shoreline, and even within several
meters of the Pinguicula communities. The former had been
made repeatedly, to within days of the site study, while the latter
was from a truck, and was likely over a year old, though the deep
vehicle tracks were clearly visible and degrading to the local beach-shoreline
plant communities affected.
During the initial field research for this project, several
qualities of Pinguicula were observed which merit further attention.
Questions raised include:
It is hoped that the continued monitoring and research of butterwort
on Beaver Island will address some of these questions and concerns.
Logistical, material, and academic assistance for this project
was given by Gilbert Starks, Daniel Wujek, and James Gillingham of
CMUBS, and is greatly appreciated.