By Charles J. Lohrmann
The playas or playa lakes typical of the North American Great Plains create unique, and generally seasonal, wetlands on the plains of North Texas, where they not only provide habitat for migrating waterfowl, but also ecosystems that support diverse species. As with other types of wetlands in North America, playas are seriously threatened (see “Playas in Peril” in the TP&W July 2006 issue). In recent years, an increasing level of research has underscored the complex impact of these wetlands not only on flora and fauna but also on aquifer recharge. Playas of the Great Plains (University of Texas Press, 275 pages, $24.95 paper) distills comprehensive research into a single academic but still highly readable volume that explains the history and function of playas and offers details on conservation. This book is essential reading for land managers and conservationists who need to understand these essential wetlands.
There’s abundant proof that playas figure into the history of human habitation throughout the Great Plains. Some of the playas, particularly those in Texas and New Mexico, include Paleo-Indian remains in their sediment. In more recent history, playas have been a source of water for irrigation as well as water for livestock. The playas were a welcome resource for early cattle herds, but are now in danger.
Whether playas have been taken for granted or just not fully understood, there has not been an orchestrated effort to conserve them. Even though some playas have been managed successfully, a shockingly high percentage have disappeared through incompatible agricultural and land management practices. Now that there’s no question about the essential role of these seasonal wetlands, a more comprehensive view of management should follow.
The book notes some odd twists in the way playas are managed. In one example, the runoff from feedlots keeps the nutrient level high enough in some playas that they do not freeze in winter. Even though this contamination is a serious problem for water quality, it means the playa offers a temporary haven for migrating waterfowl. Most contamination of playas does not offer this sort of silver lining to migrating waterfowl or shore birds. Pesticide residues cause a range of problems, including pesticide buildup in the birds themselves as well as thinning of eggshells and associated population declines.
Also from the University of Texas Press, the excellent new Texas Natural History Guides, the first two volumes of which are Texas Snakes (384 pages, $19.95) and Texas Wildflowers (384 pages, $19.95).