Why so rich? The Wapsipinicon’s roots trace back 440 million years ago, to a time when Iowa was part of a shallow, tropical sea. Sort through a pile of limestone and you are likely to find pieces of coral or brachiopod shells from the crinoids that once lived here.

 

This limestone bedrock was then covered by an event that began 2.5 million years ago as the first of the continental glaciers moved south, denoting the start of the Ice Age. The most recent ice sheet to cover the Wapsipinicon area melted away about 130,000 years ago during the end of the Illinoian glaciation. The last two glacial advances missed the valley, but cold climates reigned, creating an arctic tundra similar to northern Canada as recently as 23,000-16,000 years ago.

 

This geological history provides a rich and varied Wapsipinicon story, including many different water formations and landscapes, all of which are vital areas for Iowa’s flora and fauna. Some features and notable species include:

 

Wetlands (oxbows, sloughs, backwaters) are habitat for fish, birds, insects, amphibians, reptiles, and many mammals. The Topeka shiner, an endangered fish species, uses oxbows in the Wapsi for egg-laying and the development of young.

 

Vernal pools are places that may be underwater in spring but are dry by mid-summer. Species like jade green haircap moss, lance-leaved violet, and purple gerardia can be found here. Some of these pools include one of the rarest plants found in Iowa, orange pinweed.

 

Fens provide a constant source of mineral-rich groundwater. According to Jeff Nekola, they are home to “some 50 threatened or endangered Iowa plants, 12 rare butterflies or skippers, and several very rare mosses and snails.”

 

Riparian forests and bottomland timber include plants such as green dragon and cardinal flower, and tree species like river birch, silver maple, willow, and black walnut. Dead standing trees provide nesting sites for a variety of bird and bat species.

 

Upland forests and woodlands: Alongside common woodland plants such as wild ginger and Virginia bluebells, Nekola has identified rare flowers such as yellow lady's slippers, puttyroot orchid, and three-birds orchid. Oak, hickory, and various hardwoods add to these bountiful habitats.

 

Grasslands and prairies support myriad pollinators, birds, and mammals. The northern harrier, an endangered hawk in Iowa, requires the open grasslands that are increasingly rare in our state.

 

Sand prairies include species of native cactus like prickly pear and the threatened ornate box turtle, a land-dwelling reptile that requires loose sand for burrowing and nesting.

Limestone bluffs and cliffs house unique flora, like witch hazel and paper birch, and the endangered Iowa Pleistocene snail, a species that has lived in the area since the Ice Age and depends on cool, moist slopes.