Fritillary Habitat Conservation
THE PROBLEM
Prairies, specifically tall-grass prairies, are one of the most imperiled habitats in North America. They once blanketed the land across the Great Plains and the Midwest. Native Americans and early settlers had controlled burns for centuries. Now, tall-grass prairie makes up only less than 4% of what it once was according to the National Park Service. Urban expansion in America's Industrialization period decimated much of the fluid and diverse ecosystems for Agriculture as prairies have incredibly fertile soil. This, of course, would be problematic for all the diverse organisms that rely on this habitat.
As you can see from the historical and current range maps, the vanishing of the Regal Fritillary perfectly coincides with the destruction of habitat. The Regal isn't the only one that has vanished, though. The Ottoe, Dakota, and Arogos Skippers also require similar needs. The factor that all these species have in common is that they need large swaths of tall-grass prairie with the proper diversity of nectar and host plants. Coinciding with the Urbanization, the eastern subspecies were hit the hardest. The Eastern Regal Fritillary once flew across New England and Virginia. Now it's only confirmed population resides on a military base in eastern Pennsylvania with high quality prairies. Other Fritillaries such as the Great Spangled and Aphrodite have also decreased in New England. One has to really venture out into habitats to still see them in larger numbers. If New England keeps expanding with no regard to protecting habitats, the Greater Fritillaries may be doomed. The Fritillaries and prairie Skippers still have population strongholds in parts of the Midwest and Great Plains due to a delayed expansion and an abundance of protected land and public nature preserves.
THE SOLUTION
Many different groups are trying to protect prairies today. Perhaps the biggest problem with prairies is that they require regular maintenance in order to stay healthy and diverse. Highly controlled burning in the Spring promotes the diversity of many wildflowers. Burning seems counterintuitive to helping butterflies. Why would we want to burn them when many of them are still in diapause? It's important to only burn certain sections in certain years. This method is backed up by scientific studies (Such as this one: https://doi.org/10.1016/j.biocon.2014.03.003) The nutrient rich soil from burning increases Violet growth and pushes back against invasive species which easily overrun an ecosystem. Without burning, the prairie will very easily lose much of its value and turn into a mixed savannah. Small shrubs will grow, and invasive species will suck the nutrients out of the soil. The prairie Violets that require burning to be healthy will die out leaving the Regal Fritillary with no food, no host plants, and little habitat. This is the root of the problem. That is why there are Regal populations on military bases like Fort McCoy or Fort Indiantown Gap for example. These bases still do regular maintenance and have many acres of restored prairie. Burning is of course not perfect and if not tightly controlled, it can be extremely harmful to butterfly larvae. It is also important to make sure majority of the burning is done prior to mid-April when many of the Argynnis caterpillars awake from diapause.
Haying and grazing are also options that are used to promote prairie diversity. Controlled amounts of grazing from animals promotes plant growth and a healthy ecosystem. Haying is proven to reduce containments and nitrogen runoff. Both of these practices can be detrimental if not utilized properly. Websites such as the Missouri Prairie Foundation has more information on these management tools.
What can I do? Unfortunately, there is not a ton most can do. It is clear what needs to happen with restoring large, tall-grass prairie ecosystems but few will do it. Butterfly gardens are helpful to species like Monarchs and Painted Ladies as they can live anywhere as long as they have host plants. Butterfly gardens, however, do little to help prairie specialists. Prairie specialists simply cannot live in urban areas where their habitats are all separated and broken up. Tons of separate gardens do not equate one massive habitat as they really are not able to migrate. The best thing we can do is monitor populations and conserve habitat wherever found.
Prairie specialist butterflies are not like the White Rhino being poached to extinction or certain bats targeted parasites and sickness. The biggest factor is just habitat. These species are R-strategists in the sense of their massive reproductive potential. As we see from large population strongholds, success is possible. Conservation can be summed up into one word: HABITAT!
The Hogback Ridge in southwestern Wisconsin hosts several prairie specialist species like the Regal Fritillary and Bird's Foot Violet.
An illustration of Bird's Foot Violet, the main host of the Regal Fritillary.
The Arogos Skipper is an imperiled prairie specialist. Image is by Dennis Vollmar.
A typical large-scale prescribed burn.
An example of post-burn wildflower diversity at the Catholic Ecology Center in Neosho, Wi.