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Adapting southern bog relicts and oak woodland at Beulah Bog State Natural Area to climate change.

Beulah Bog provides a sanctuary for southern outliers of bog and tamarack swamp communities that more typically occur in the northern part of the state. These rare ‘climate relicts’ have persisted due in part to the cool, moist microclimate of the glacial kettles in which they occur and the adjoining upland oak savannas and grasslands. Restoring these upland communities will not only support the unique species associated with them, but may also increase the adaptive capacity of the site’s wetlands to tolerate a range of temperature and moisture conditions.

Project Area

WI DNR photo - Beulah Bog boardwalk
Beulah Bog lies in a series of four kettle holes and features an undisturbed bog with many unusual plants more typical of northern bogs. Classical stages of ecological succession are exhibited in the bog including: a shallow bog lake dominated by watershield with white and yellow water-lilies and extensive floating mud flats; an advancing, quaking sedge and sphagnum mat between 25 and 50 feet wide; northern wet forest of tamarack and bog shrubs and; a wet open moat surrounding the main bog, dominated by wild calla and cattails. Undisturbed bogs in this area are rare and the site supports several regionally rare plants with more northern affinities including dense cotton grass, large and small cranberry, and small bladderwort. The site harbors six species of insectivorous plants including pitcher plant, sundew, and bladderwort. The bog lake provides habitat for several dragonfly species and other invertebrates. Beulah Bog is owned by the DNR and was designated a State Natural Area in 1975.

While part of Kettle Moraine State Forest, the state natural area is isolated from proximal forest lands, and is surrounded mostly by croplands and subdivisions, along with scattered wetlands and upland forest. The topography of the region is dominated by glacial kettle-moraine features. Bog relicts and southern tamarack swamp are found in the low kettle areas and support several species of insectivorous plants along with many bog indicator species that are uncommon in this region of the state. The upland ridges contain oak opening/oak woodland and grassland habitats. The open moat surrounding the bogs contains native species of floating-leaved, submergent, and emergent vegetation which intergrades with the mossy floating mat and tamaracks.

Management Goals

Goals for the site include:

  • Control invasive species and promote natural habitats.
  • Restore native prairie and oak opening habitats along ridge tops and slopes.
  • Conserve bog relicts and southern tamarack swamp.
  • Promote shore-line habitats already present: southern sedge meadow, emergent marsh, calcareous fen.

Key objectives include:

  • Halt expansion of invasive species populations, limiting them to no more than 5-10% total cover.
  • Utilize chemical, mechanical, and prescribed fire techniques to check invasive populations.
  • Increase prairie and oak establishment (by: using native seed to establish prairie grasses and forbs; continue with prescribed fire regimen; continue management of invasives through use of herbicides and mechanical methods; remove tree species that are not native to these habitat types.)
  • Protect and promote habitat for rare species in wetlands and uplands .
  • Survey for rare species and monitor for evidence of trampling or removal of native plants.
  • Survey areas that are vulnerable to invasions of non-native invasive species (e.g., areas prone to flooding, inundation, and erosion) and control new infestations.
  • Maintain signage, and boardwalk to allow for educational opportunities within the community.

Climate Change Impacts

For this project, the most important anticipated climate change impacts include:
More extreme heat may particularly affect bog relicts.
Increasing water temperatures over time may lower water tables and affect peat decomposition.
More frequent and intense storms may transport invasives to site; associated runoff may cause erosion, bring sediment and nutrients that enhance growing conditions for invasives.
More frequent and intense storms may cause erosion after prescribed burns.
Longer growing seasons, elevated CO2 in combination with other stressors may increase the presence of invasive species in the uplands, and contribute to brush invasion in the savannas.
Prairies and savannas are adapted to drought and warmer temperatures.
Shading caused by faster brush growth may limit white and bur oak regeneration on ridges and slopes, as well as allow more shade tolerant tree species to persist.
Habitat is projected to decline for tamarack trees as the climate continues to change, however local microsite bog conditions offer cooler temperatures, and the floating mat and sphagnum may buffer this species from significant losses.
If the Tamarack trees are lost the bog’s vulnerability increases as it would convert to a new ecosystem type.

Challenges and Opportunities

Climate change will present challenges and opportunities for accomplishing the management objectives of this project, including:


May not be feasible to manage for tamarack swamp if tamarack cannot cope with changing climate. Tamarack swamp may convert to shrub-carr
Opportunities to restore native prairie and oak opening habitats on ridges with prescribed fire may decrease. Spring burn windows may shrink as green-up occurs earlier and more days are lost to heavy rain creating conditions too wet to burn.
Without fire, woody invasive species on-site are likely to increase due to longer growing seasons and elevated CO2, such that halting expansion of invasive species is unlikely.
Protection and promotion of habitat for rare species native to bogs may be affected by stormwater runoff, invasive species, and changing moisture regimes. Rare species may decrease and become more difficult to monitor.
Increased presence of forb invasive species may occur when erosion exposes bare soils. New invasive species may migrate to site, such as kudzu.
Intense rain may affect recreational access to bog if boardwalk is flooded or damaged.


Geographic isolation of this bog relict ecosystem may reduce possibility of insect invasion affecting tamarack trees.
Cooler, moister microclimates in kettle ‘bowls’ may help to buffer wetlands from significant change.
Sphagnum moss and floating mat buffer wetlands from water level changes and increasing temperatures.
Ridge tops contain aspen and black cherry which are predicted to lose suitable habitat, this could benefit long term efforts to restore oak opening habitat and native prairie.
Drier conditions may favor drought- and heat-tolerant prairie and savanna species, while disfavoring invasives on the ridge tops and slopes.
Extreme decreases in moisture along ridge tops may stress invasive plants and help control their expansion.
Native prairie plant seeds can be interseeded with forb species to increase the adaptive capacity of sites to cope with altered soil moisture and warmer conditions.
Late summer prescribed fire burn windows may become more frequent. Summer burning can help to control brush.
Climate change threats may help to educate importance of bog ecosystems and create opportunities to increase educational signage and outreach.

Adaptation Actions

Project participants used the Adaptation Workbook to develop several adaptation actions for this project, including:

Outline and implement invasive monitoring program that occurs throughout the 3 seasons every three years.
Utilize on-the-ground phenological cues rather than calendar dates to identify appropriate treatment windows for invasives
Monitor sites that are vulnerable to invasions (e.g., areas prone to flooding, inundation, and erosion) and control new infestations early on.
Consider conducting burns in late summer to avoid periods of high precipitation, thereby decreasing risk of erosion.
Summer or fall burns exhibit enhanced fire behavior with drier conditions, and will likely require changes in ignition tactics (e.g., flanking burn, internal spot-lighting, rake around trees, burn around trees) to minimize damage to native trees.
Increase frequency of invasive species treatments in response to increasing abundance (using foliar sprays and brushcutting).
Use phenological cues on-site to determine the best time for treatment of invasive species.
Direct habitat restoration and tree removal to reduce aspen and black cherry. This will ultimately favor growth of bur and white oaks in addition to hickory.
Lay native seed to establish native woodland species, favoring species that are likely to persist under a changing climate (e.g., species with ranges extending to the south), as well as species that are drought- and shade-tolerant.
Monitor areas that are vulnerable to establishment of invasive species (such as gullies near the road to the west of the site) and control new infestations early.
Minimize loss of rare or unusual plants in bog and tamarack swamp by monitoring for establishment of invasive species in the bogs and reducing impacts of erosion on the slopes.
Modify elevation of boardwalks to accommodate higher water levels.
Create educational signage on upland trails to promote public awareness of changing water levels, possible trail flooding.


Project participants identified several monitoring items that could help inform future management, including:
Survey or monitor site to identify points of invasive species invasion.
Forest inventory to track growth of hickory in sapling, subcanopy, canopy.



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