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General
Description
Major Science & Stewardship Activities
Full Size Images The Nature Conservancy, IL |
Elgin, IL
Bluff Spring Fen Preserve Profile
Bluff Spring Fen is a 91 acre complex of prairie, wetland and savanna communities. This Illinois Nature Preserve contains high-quality graminoid fen, dry gravel prairie, sedge meadow and calcareous seep communities. No other natural area in Illinois contains this assemblage of communities.
Bluff Spring Fen is located in NE Illinois in the city of Elgin. The Fen is south of the Bluff City Cemetery. It borders a portion of Poplar Creek, which feeds into the Fox River, a major tributary to the Illinois River.
- Dedicated as an Illinois Nature Preserve in 1987
- All of the restoration management has been done by a strong volunteer group called Friends of the Fen
- The Healy Road Prairie was transplanted to this site in July 1990.
Four endangered, four threatened and nine rare plant species occur in the fen. There are also several species of rare butterflies such as the Baltimore checkerspot (Euphydryas phaeton) as well as fish species including mottled sculpin (Cottus bairdi) and brook stickleback (Calaea inconstans).
One of the major threats to the fen is the invasion of non-native and aggressive native plants. The main species of concern are reed canary grass (Phalaris arundinacea), common reed (Phragmites australis), glossy buckthorn (Rhamnus frangula) and water cress (Nasturtium officinale). Encroachment of these species into the fen has led to the decline of some populations of native species.
Another concern is the threat to the groundwater system. Some gravel mining occurred at this site before it was protected. There is evidence that fen species were displaced and therefore some groundwater disruptions probably occurred. There has also been a proposed project within the recharge zone that could have caused some groundwater disruption, but as of now this project has been put on hold.
Major Science and Stewardship Activities
- Butterfly monitoring has been ongoing since 1987. Bird monitoring and vegetation monitoring are also ongoing.
- Some preliminary groundwater monitoring has been conducted with plans to expand the study at a future date.
- There have been three scientific papers published concerning the unique plant communities at the Fen.
Bluff Spring Fen lies within the Morainal Section of the Northeastern Morainal Natural Division of Illinois. It contains glacial outwash from the West Chicago Moraine to the east. There are several kames that support dry gravel hill prairies. However, some of the kames were mined in the past and have been depauperate of vegetation. There has also been all-terrain vehicle use that has led to decreases in vegetation on kames.
A portion of the floodplain of Poplar Creek is contained in the western edge of Bluff Spring Fen. The topography is gently rolling with a number of the kames mentioned earlier rising from 700 to 760 feet above sea level.
The kames are the site for our dry prairie community. Most of the dry prairies have vanished from Illinois due to gravel mining and grazing. The western kame has a variety of species including prairie smoke (Geum triflorum) which is at the eastern edge of its range. The eastern kame contains fringed puccoon (Lithospermum incisum) and wooly milkweed (Ascepias lanuginosa). The dominant grasses that are found on both kames are dropseed (Sporobolus heterolepis), little bluestem (Andropogon scoparius) and side-oats gramma (Boutelloua curtipendula).
There are small areas of mesic prairie with big bluestem (Andropogon gerardii) and Indian grass (Sorghastrum nutans). The conservative species usually found in these communities are absent because of past grazing practices. The only exceptions to this are the areas where prairie grades into fen. Many of the mesic species present are those that can survive in either fen or dry prairie.
Savannas are present on the kames and at the western edge of the cemetery. Before restoration began, few of the native species other than bur oak (Quercus macrocarpa) remained. Today these areas have silky wild rye (Elymus villosa), bottlebrush grass (Hystrix patula), poke milkweed (Asclepias exaltata), pointed tick trefoil (Desmodium glutinosum), and wild yam (Dioscorea villosa).
The fen area is the gem of this site. It contains highly calcareous water that continuously flows from seeps in the area. Fen communities are confined to only the northern third of the state. They were fairly common prior to settlement, but today they represented one of the rarest communities in Illinois. There are six species of orchids including three endangered species. There are also rare and endangered grasses, shrubs and sedges in this area as well.
Marl flats are unique communities that are interspersed within the fen. Most plants are prevented from growing in this are due to the high concentrations of calcium carbonate and other mineral precipitates. However, there are high quality species that utilize this area including shrubby cinquefoil (Potetilla fruticosa) and prairie dock (Silphium terbinthinaceum).
There are a number of small streams found throughout Bluff Spring Fen. They originate from the more than 14 springs and seeps in the area. Rare species such as water parsnip (Berula pusilla) and mottled sculpin (Cottus bairdi) can be found in these clear unpolluted streams.
Although there are still many challenges to face in restoring this area, Bluff Spring Fen contains a fantastic variety of flora and fauna. This profile only touches briefly on some of the highlights that this preserve contains. I would encourage all of you visiting the Chicago area (especially in May/June) to come out and visit this wonderful and rare natural jewel.
To find out more information about Bluff Spring Fen, please contact Mel
Manner at 847-464-4426 or e-mail her at manner@foxvalley.net.
