The Watercress Darter: a survivor’s tale

Against all odds, the Watercress Darter (Etheostoma nuchale) has survived. At least for now. This little fish has the misfortune of being found only within Jefferson County, the most urbanized county in Alabama. Somehow, it has survived several decades of agriculture, an explosion of mining and related industry, and the founding and expansion of Birmingham. Its tale of survival is one that interweaves its biology with the geology and cultural history of Birmingham.

The fish was discovered in 1964 by Samford University biologist Mike Howell, when he collected the fish from Glenn Spring in Bessemer. Subsequent surveys found the darter in two other springs, Roebuck (in east Birmingham) and Thomas (in Bessemer). With its limited distribution in one of the Southeast’s largest cities, the fish was placed on the endangered species list by the U.S. Fish and Wildlife Service in 1970. In 1980 the Watercress Darter National Wildlife Refuge was established at Thomas Spring. An artificial pond was created downstream from the spring to provide an additional habitat for the species. This pond is at the end of the nature trail at the refuge.

Despite the protection afforded by its endangered status, studies from 1985-1991 suggested a downward trend in the populations of the fish at all three springs where it naturally occurred. In 1988, a reserve population of the fish was successfully established in Tapawingo Spring (also known as Penny Spring) in Pinson. In 2003, a fourth naturally occurring population was discovered in Seven Springs in Birmingham’s West End neighborhood of Powderly, on land owned and managed by Faith Apostolic Church. Surveys of all darter populations occurred in 2006-2008, and again in 2011. Over this time period, some populations have remained stable, while others appear to have declined.

The springs of the area have saved the fish. Without the refuge they provide, the darter would not have survived nearly 150 years of industry and urbanization in the Jones Valley. It is likely that before Birmingham was founded, the species inhabited many more springs in the valley and, perhaps, some of its streams. Back then, the streams of the area would have clear waters and aquatic vegetation.

But as development spread, the waters of Jones Valley became increasingly unsuitable for the darter and other sensitive animals. Some streams were rerouted into linear ditches or shunted into underground tunnels beneath the city. Streams were used as a cheap way to dispose of industrial waste, wastewater, and even sewage. The paving over of the watershed created flash flooding that destroyed stream habitats. The deforestation that accompanied urbanization removed the shade that would keep the streams cool in the long, hot summers.

Springs were not totally immune to these problems. Some were ponded and filled with silt. Others were diverted into the stormwater system or filled in for convenience. But a few survived, and at least four of these became a sanctuary for the Watercress Darter as the city grew. These springs provide a relatively constant supply of clean, cool water and appropriate habitat for the fish. There are still many threats to the darter, but with a little help, the fish just might avoid extinction.

-R. Scot Duncan