Photo by Eric Epstein
- WDNR
State Rank: S2 Global Rank: G2Q what are these ranks?
Hemlock relicts are small patches of mesic forest composed mostly of species that are disjunct from and generally far south of their usual Wisconsin ranges. Most documented relicts occur in southwestern Wisconsin's Driftless Area, within the Western Coulees and Ridges Ecological Landscape. Typical sites are deep, steep-sided, moist ravines, with cool northern or eastern slope exposures. Exposures of bedrock, most often Cambrian sandstones, are typically present and contribute to the ability of this community to develop and persist in areas that would otherwise be vegetated with deciduous hardwood forests. The porous sandstone has a high capacity to hold water, which slowly moves through the rock and keeps conditions humid and cool. The dominant tree is most frequently eastern hemlock (Tsuga canadensis). Eastern white pine (Pinus strobus), yellow birch (Betula alleghaniensis), and paper birch (Betula papyrifera) are common northern canopy associates. Other trees present are usually those present in the adjoining hardwood forests. Shrubs and herbs with northern affinities are also important, and may include mountain maple, Canada yew (Taxus canadensis), showy mountain ash (Sorbus decora), blue-bead lily (Clintonia borealis), rose twisted-stalk (Streptopus roseus), shining club-moss (Huperzia lucidula), and spinulose wood fern (Dryopteris carthusiana). The dense shade of the hemlock combined with the northern aspect of many stands means that very little light reaches the forest floor causing a very sparse groundlayer.
Hemlock relicts are highly localized in southwestern Wisconsin. They are concentrated in a few areas, such as the drainages of the upper Kickapoo and Baraboo Rivers, and in a few of the deep gorges that cut into the flanks of the Baraboo Hills. Extremely isolated outliers are known from a few sites south of the Wisconsin River. Unusual plants and animals have been documented in several stands. These include periglacial relicts, that for various reasons were unable to keep pace with changes to the vegetation as the climate changed following the last glacial advance, and a number of habitat specialists that are rare elsewhere in southern Wisconsin.
The following Species of Greatest Conservation Need are listed according to their level of association with the Hemlock Relict natural community type, based on the findings in Wisconsin's 2015 Wildlife Action Plan.
Scores: 3 = high association, 2 = moderate association, and 1 = low association. See the key to association scores for complete definitions.
| Birds | Score | |
|---|---|---|
| Acadian Flycatcher | Empidonax virescens | 2 |
| Cerulean Warbler | Setophaga cerulea | 1 |
| Eastern Whip-poor-will | Antrostomus vociferus | 1 |
| Least Flycatcher | Empidonax minimus | 1 |
| Grasshoppers and allies | Score | |
|---|---|---|
| Black-striped Katydid | Scudderia fasciata | 2 |
| Mammals | Score | |
|---|---|---|
| Northern Long-eared Bat | Myotis septentrionalis | 2 |
| Silver-haired Bat | Lasionycteris noctivagans | 2 |
| Tricolored Bat | Perimyotis subflavus | 2 |
| Big Brown Bat | Eptesicus fuscus | 1 |
| Little Brown Bat | Myotis lucifugus | 1 |
| Reptiles | Score | |
|---|---|---|
| Gray Ratsnake | Pantherophis spiloides | 1 |
Please see Section 2. Approach and Methods of the Wildlife Action Plan to learn how this information was developed.
The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.
| Scientific Name | Common Name | Score |
|---|---|---|
| Rhododendron lapponicum | Lapland Azalea | 2 |
The following Ecological Landscapes have the best opportunities to manage for Hemlock Relict, based on the Ecological Landscapes of Wisconsin Handbook.
| Ecological Landscape | Opportunity |
|---|---|
| Western Coulee and Ridges | Major |
| Southwest Savanna | Important |
| Central Sand Plains | Present |
Major (3 on map)
A major opportunity for sustaining the natural community in the Ecological Landscape exists, either because many significant occurrences of the natural community have been recorded in the landscape or major restoration activities are likely to be successful maintaining the community's composition, structure, and ecological function over a longer period of time.
Important (2 on map)
Although the natural community does not occur extensively or commonly in the Ecological Landscape, one to several occurrences do occur and are important in sustaining the community in the state. In some cases, important opportunities may exist because the natural community may be restricted to just one or a few Ecological Landscapes within the state and there may be a lack of opportunities elsewhere.
Present (1 on map)
The natural community occurs in the Ecological Landscape, but better management opportunities appear to exist in other parts of the state.
Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.
Threats/issues and conservations actions for natural communities
The following are additional considerations for Hemlock Relict in Ecological Landscapes with opportunities for protection, restoration, and/or management. For more information, see the Wildlife Action Plan.
This community occurs locally at the extreme southern edge of this Ecological Landscape, for example Blackhawk Island in the Dells of the Wisconsin River (Juneau County), and Witches Gulch (Adams County).
This community may be seen at Mt. Pisgah Hemlock-Hardwoods State Natural Area in Wildcat Mountain State Park (Vernon County), within the Kickapoo Reserve (Bridge 8 Woods and Cliffs State Natural Area, Vernon County), and at Hemlock Draw (Sauk County).
Click to view a larger version. Please considering donating your photos to the Natural Heritage Conservation Program for educational uses. Photo use
Hemlock relicts often occupy northern or eastern exposures on or in the vicinity of porous sandstone cliffs undercut by streams. Plant associates are a mix of N and S species, plus a few habitat specialists.
Photo by Eric Epstein.
This dense thicket of sapling hemlock is thriving under a canopy of large white and red oaks along a spring run above the Kickapoo River. Wilton Hemlocks, Monroe County.
Photo by Eric Epstein.
Note: photos are provided to illustrate various examples of natural community types. A single photograph cannot represent the range of variability inherent in a given community type. Some of these photos explicitly illustrate unusual and distinctive community variants. The community photo galleries are a work in progress that we will expand and improve in the future.