COLUMBUS (WCMH)-All those colorful summer blooms along country roads and in the woodlands that are now peaking as the summer calendar melts into August provide an essential habitat for the dwindling populations of the Monarch butterflies.

Native Ohio wildflowers-Purple Cone flowers, Asters, Black-eyed Susans, purple cone flowers, goldenrod and butterfly milkweed-provide nectar for the monarchs that migrate north every spring, after overwintering in Mexico, Southern California and South Florida.

Dr. David Shetlar, an Ohio State entomologist, says the populations have declined about 50 percent in the past decade, mostly a result of warmer winter weather and the loss of forests in the specific location in central mountains of Mexico, where they return precisely each year by the millions from areas east of the Rocky Mountains.

The adult population likely suffers from decreased energy needed for the annual flight that covers about 3,000 miles, Shetlar explained. Smaller groups west of the Rockies head for Southern California in the fall, and some eastern butterflies winter in South Florida.

Some herbicides used in agriculture reduce milkweed coverage, according to Shetlar. “This has the indirect effect of eliminating the host plant for monarchs, but the herbicides themselves are not toxic to the butterfly or its larva.” A decrease in milkweed diminishes the population by removing a place for the butterflies to deposit their eggs and a food source.

ODNR naturalist Jim McCormac recommends planting native wildflowers in your backyard, including butterfly milkweed, which gives monarchs a place to lay their eggs in the late spring,, and something for their young (emerging caterpillars) to feed on starting in about 40 days later.

Shortening daylight commences the winter flight home in September, completing the majestic yearly cycle.