Ecological Significance

An impressive suite of rare and imperiled animals thrives in beautiful Ouachita Mountain rivers, streams, lakes and aquifers that millions of people each year use for drinking, agriculture and recreation. Twenty-three aquatic animals in the Ouachitas, including 12 crayfish, eight fish, and three mussels, are found nowhere else on Earth.

Threats

Scientific studies have shown that a variety of land-use activities, when managed poorly, threaten the health of Ouachita Mountain streams. Urban development, incompatible forestry practices, in-stream gravel mining, unpaved roads, municipal and industrial wastewater, and cattle grazing too close to stream banks have the potential to harm water quality and the plants and animals that depend on clear streams. Several of these activities can cause excessive sedimentation, which has been pinpointed as a major threat to Arkansas’ most pristine streams. Too much sediment not only causes murkier water, which can affect sight-feeding fish like smallmouth bass, but it also smothers gravel beds, choking out insects, larvae and smaller fish that live there. Altered water flows caused by the construction of dams, increased water withdrawals and water diversion can also degrade streams. The most critical way these practices can change a stream is by reducing the periodic high flow that is necessary to flush out fine sediments.

What We've Done

The Nature Conservancy began its work with priority rivers in the Ouachita ecoregion during the 1980s, when it helped the U.S. Forest Service purchase the Albert Pike area along the upper Little Missouri River. In 1987, the Conservancy helped create the Cossatot River State Park-Natural Area by purchasing and transferring 4,400 acres to Arkansas State Parks and the Arkansas Natural Heritage Commission. And in 1996, the Conservancy facilitated a land exchange between Weyerhaeuser Company and the U.S. Forest Service that brought more than 180,000 acres into conservation management at no cost to taxpayers. In Arkansas, the exchange added to the protection of the upper Missouri, upper Saline and Cossatot rivers.

Recently the Conservancy has zeroed in on the Saline River, which is the only major undammed river in Arkansas that flows from the Ouachita Mountains and is known among biologists for its abundance and diversity of mussels. In 2005, the Arkansas Natural Resources Commission tasked the Conservancy with analyzing land-use practices, describing the biggest threats to the Saline River and suggesting appropriate restoration activities. After a two-year study identified sediment as the worst problem, the Conservancy prioritized sediment sources within a sub-watershed of particular interest, the Middle Fork of the Saline. There the Conservancy analyzed and mapped land-use patterns throughout the watershed and quantified their impact on the Middle Fork in order to develop targeted conservation strategies. With this data and funding from the U.S. Fish and Wildlife Service, the Conservancy partnered with the Arkansas Game and Fish Commission in 2009 to implement its first of many restoration projects within the Saline River watershed – stabilizing a 2,600-foot section of bank along the Middle Fork that was responsible for 2,770 tons of soil loss each year.

Ongoing Conservation Actions

In addition to its work on the Saline River, the Conservancy is advancing conservation of the Caddo and Ouachita rivers. Project teams are creating comprehensive, science-based conservation plans that result from collaboration among local communities, individual landowners, and state and federal agencies. These plans identify ways in which land uses can be managed to ensure the health of local streams. For instance, at the Saline, Caddo and Ouachita rivers, the Conservancy is working with interested cattle ranchers on grazing techniques, fencing and alternative watering sources that limit areas where cattle access streams, a move that will keep critical stream bank vegetation intact. The Conservancy has taken an inventory of unpaved roads in the upper Saline River watershed, identified those spots responsible for the most sediment runoff, and secured state funding to begin repairing them. The Ouachita rivers team plans to replicate the process in other priority watersheds in the region.

Photos at top (let to right): The Little Missouri River © Joy DeClerk/TNC; Great egret © Mike Fuhr/TNC.