4/14/2025 Butterflies are in trouble. You can help them! 

A recent study published in the journal Science revealed that butterfly populations in the United States declined 22% between 2000 and 2020. The drop in the Northeastern United States was even worse: 32.6%. Much of the data used for this study came from butterfly counts sponsored by the North American Butterfly Association, in which Bowman’s Hill Wildflower Preserve has participated since 2012.

The likely reasons for the steep decline in butterflies are pesticide usage, habitat loss and climate change.

These numbers are pretty depressing, but a deep dive into the data yields some interesting findings that offer hope that we can help reverse this trend. While the nationwide numbers for Monarch butterflies are inconclusive for the period covered by the study, Monarchs increased by 79% in the Northeast and by 47% in the Southeast. It seems likely that the recent emphasis on planting their required caterpillar food, milkweed (Asclepias spp.), is a big factor in the improving numbers. Offering
nectar for butterflies is not enough for a species’ survival. Food for their caterpillars is also essential. Some species whose territory was primarily in the southern U.S. are increasing in the north. Sleepy Orange ( Abaeis nicippe) and Giant Swallowtail (Papilio cresphontes Cramer) are two examples seen at the Preserve. This territory expansion is only possible because the range of their caterpillar food plants reaches northern regions, Wild Senna (Senna hebecarpa) for Sleepy Orange, and Hoptree (Ptelea trifoliata) and Northern Prickly Ash (Zanthoxylum Americanum) for Giant Swallowtails.
Ready for more depressing statistics? More than 40% of insect species worldwide are declining. Bird populations have declined almost 30% in the past 50 years. The good news is that we can take action to reverse these trends, often by doing less.

Here’s how you can help:

• Use plants that are native to our region.
•  Provide nectar sources throughout the growing season.
• Offer caterpillar food plants. Like Monarchs, most butterfly species require a few
  closely related plants as their caterpillar food.
• Replace as much of your lawn as possible with native plants. 
• Don’t use pesticides or herbicides!  
• Leave the fallen leaves in your flower beds.
• Leave spent perennials standing in your garden. They provide habitat for insects and food for birds.
• Know and remove invasive plants, including butterfly bush.

With these same steps, we’re helping ourselves. We rely on insects to pollinate our food, aerate the soil, break down debris, feed other animals and help keep other insects in check. These actions will save money, energy, time, reduce fossil fuel and water usage, and help mitigate the effects of climate change by removing pollutants from the air and water, reducing air temperatures and enabling the ground to absorb more stormwater, reducing runoff, erosion and flooding. 

What we do in our gardens matters.

Article and photos by Mary Anne Borge