Prairies of the Lakeshore Nature Preserve

Prairies are grassland environments mainly covered by native grasses and a wide variety of flowering herbaceous plants known as forbs. The exact mixture of grasses and flowering plants varies depending on environmental conditions, especially factors such as rainfall, landscape features, soil depth, and nutrient availability.

The richest prairie habitats, including tallgrass prairies and mesic prairies, which receive a moderate amount of moisture, support extremely diverse plant communities. Some grasses in these areas can grow more than 8 feet tall. These landscapes are especially enjoyable to explore because new species of forbs, or non-woody flowering plants other than grasses, bloom throughout the growing season. Their flowers attract butterflies, pollinating insects, and many bird species that rely on these habitats for food and nesting.

Historical Distribution of Prairies in Wisconsin

Historical land surveys indicate that tallgrass prairies and oak savannas once occupied large portions of southern Wisconsin. Today, nearly all of these ecosystems have vanished because their fertile soils make them highly valuable for farming.

Mixed-grass and shortgrass prairies are more commonly found farther west of Wisconsin, where rainfall decreases toward the Rocky Mountains. However, small remaining patches still exist in Wisconsin, especially in areas such as sandy barrens and steep rocky slopes where agricultural development is difficult.

Wisconsin lies within a transition region between the deciduous forests of the eastern landscape and the prairie grasslands of the west. Although prairie plants, including those from moist prairie environments, are generally more tolerant of drought than broadleaf forest trees, scientists recognize that fire was one of the most significant forces shaping these ecosystems.

The Role of Fire in Prairie Formation

Before European settlement, natural fires caused by lightning and intentional fires set by Indigenous peoples regularly moved across the landscape every few years in areas without natural barriers to stop them.

Prairie plants are especially adapted to fire because a large portion of their total biomass, sometimes up to 66 percent, exists below ground. This extensive root system allows them to quickly recover after burning or grazing. Fire also prevents shrubs and trees from taking over open grasslands, reduces invasive plant growth, clears dead plant material from the surface, helps the soil warm faster in spring, and releases nutrients back into the ground.

Regular burning can encourage stronger growth and increased flowering among many prairie species. As a result, forests expanding westward into grasslands were restricted by dry conditions and recurring fires, while prairies moving eastward were limited because smaller prairie plants could not effectively compete with trees for sunlight.

Restoring Prairie and Savanna Habitats

Efforts are underway to restore prairie and savanna ecosystems in the Lakeshore Nature Preserve, but rebuilding these habitats requires patience and long-term management.

Once established, prairies are highly resilient, especially when they receive regular prescribed burns. However, creating a new prairie can be challenging, particularly in locations where invasive weeds have already become dominant.

Prairie plants are perennial species that invest much of their energy in developing strong root systems during their early years. This growth strategy makes them slower to establish above-ground growth compared with pioneer plants, commonly known as weeds. These fast-growing competitors quickly produce stems, leaves, flowers, and large quantities of seeds, allowing them to dominate before prairie plants have fully developed.

With careful restoration efforts, proper fire management, and time, prairie communities can gradually return and once again support their remarkable diversity of plants, insects, and wildlife.