Saturday, April 25, 2015

Healthy Prairies Mean Healthy Monarchs

Welcoming Fire Back to the Landscape

Prescribed burning at Fahl Waterfowl Production Area. Photo by Alex Galt/USFWS.
Prescribed burning at Fahl Waterfowl Production Area. Photo by Alex Galt/USFWS.

Fire is good for monarchs? Yes. The blackened, charred remains of a prairie after a prescribed burn might look catastrophic, but the opposite is the case when it comes to monarch health. To understand how prescribed burning benefits habitat for monarchs and other prairie wildlife, you first need to know what makes prairies look and function the way they do.

Techniques, like prescribed burning, when combined with other restoration efforts, collectively creates monarch habitat. A great example of this in action is at Morris Wetland Management District in Minnesota. Every year Morris biologists make sure to include milkweed and more than 40 other native wildflower seeds in new prairie plantings. This habitat has direct benefits for monarchs and other prairie species by providing food and shelter during all stages of a monarch’s life while in Minnesota. Planting prairie is important, but it’s not enough by itself.

History can tell us a lot about how we can restore and maintain healthy prairies today. Native prairie and grasslands are often referred to as “disturbance-dependent ecosystems,” because relatively frequent disturbance events - like fire, herbivory, and weather events - greatly influence prairie plants and animals. Without these three major disturbance types happening over long periods of time on the prairie landscape, North America would most likely look much different. Various forest types would dominate today instead of the mosaic of prairie and wetland habitats that we associate with the Midwest. The wildfires that burned uncontrolled across the prairies in the past set back the growing cycle of trees and shrubs, and favored plants like grasses and wildflowers. Grazing and browsing by large herbivores, such as bison and elk, further modified plant communities. Rain and snow affected how the prairies grew in the same way they influence the growth of agricultural crops today.
Although there are still many things about nature that we don’t fully understand, we do know that these disturbances didn’t happen consistently or at the same intensity over the years. This variation caused different types and complexities of plant communities, a trait we call habitat heterogeneity. These diverse prairie plant communities attract a wide array of migratory birds, pollinators, and other prairie wildlife.

The absence of wildfires and large herbivores makes active habitat management crucial for maintaining high quality native prairies in the Midwest today. Many decades of prescribed burning at Morris Wetland Management District have taught our resource managers a lot. Fire can significantly influence habitat conditions. Prescribed burning is an invaluable tool for increasing the diversity of wildflowers on existing prairies and is still one of the best ways to keep trees from turning grasslands into forests – in other words, keeping prairies healthy.  And in the end, one of the best ways to help monarchs is to make sure we have healthy prairies.