Panhandle Playa Lakes
Playa lakes are arguably the most significant ecological feature in the Texas High Plains, even though they cover only 2 percent of the region’s landscape. Playas are shallow, circular-shaped wetlands that are primarily filled by rainfall, although some playas found in cropland settings may also receive water from irrigation runoff. Playas average slightly more than 15 acres in size. Although larger playas may exceed 800 acres, most (around 87 percent) are smaller than 30 acres. Approximately 19,300 playas are found in the Texas High Plains, giving us the highest density of playas in North America. The lake shown to the left is within cropland.
Compared to other wetlands, playas go through frequent, unpredictable, wet/dry cycles. In wet years they support the production of annual plants, such as smartweeds and millets. These plants produce a tremendous crop of seeds that are favored by dabbling ducks and other seed eating birds. The wet/dry nature of playas, along with their high plant production, means they produce an abundance of invertebrates. This productivity makes playas havens for birds and other wildlife throughout the year.
Playa lakes and birds
During migration periods, playas are often besieged with spectacular numbers
of cranes, waterfowl, and shorebirds. Playas are critical “refueling
points” for shorebirds making their way to wintering areas on the Gulf
Coast or south of the U.S. border. Surveys in the early 1990s documented that
30 species of migrating shorebirds used playa lakes, with American Avocets,
Lesser Yellowlegs, Long-billed Curlews, Long-billed Dowitchers, Stilt Sandpipers,
and Wilson’s Phalaropes being the most abundant. Most North American
dabbling and diving ducks also use playas during migration. Blue-winged Teal,
Green-winged Teal, Gadwall, and Northern Pintails are common during early
autumn. During spring, Gadwall and Blue-winged Teal often linger long after
most Mallards and Northern Pintails have departed for their more northerly
The Playa Lakes Region is second only to the Gulf Coast in providing habitat for wintering waterfowl in the Central Flyway. The most conspicuous species during winter are Canada Geese and Snow Geese. Recent estimates suggest that 300,000 geese are found in the Playa Lakes Region. Mallards and Northern Pintails are the most abundant wintering ducks.
Although important, playa lakes can be a harsh environment for wintering birds. The High Plains is subject to periodic drought and to hard freezes during winter. In a recent January waterfowl survey, it was estimated that more than 90 percent of the available playas (those with water) were frozen. During these extremely cold periods, waterfowl are forced to move to large reservoirs or rivers. Additionally, waterfowl wintering in the playa region continually move to find suitable wetlands and food. Daily flights for ducks and geese foraging in agricultural fields can cover many miles. This means the conservation of all playas, and other wetlands, is important.
Playas have a surprising number of nesting shorebirds and waterfowl. Breeding American Avocets and Black-necked Stilts are found on most wet playas. Blue-winged Teal and Mallards that nest in the prairie grasses and wheat fields of the High Plains depend on playas as brooding areas for their young. During wet springs and summers, 250,000 waterfowl may be produced in the Playa Lakes Region of Texas.
Playa lakes are threatened
Since the first attempts to raise cattle and crops in the High Plains, playas
have been subject to continual threats. Early settlers dug pits in playas
to concentrate water and slow evaporation so that livestock would have a watering
source during droughts. This practice continues today, although it is not
as common as it once was. Most alteration to playas has been the result of
farming practices. Estimates suggest approximately 70 percent of playas larger
than 10 acres have had pits dug in them to concentrate water for row-water
(or furrow) irrigation. This form of irrigation is declining and modern, more
efficient irrigation practices that rely on groundwater do not require these
pits. Road construction has also impacted playas. Approximately 10 percent
of playas have roads constructed in their basins.
The most insidious threat to playas is the indirect effect of poor farming and grazing practices. Playas in croplands have suffered severe sedimentation as a result of soil erosion in adjacent croplands. Playas affected by sedimentation tend to be shallower and lose their capacity to hold water. In rangelands, the problem facing playas is over grazing. Livestock allowed access to playa basins during the growing season often remove many of the seed producing plants that are preferred by waterfowl and other birds.
Playas and the Ogallala
Once the subject of much debate, mounting evidence points to playa lakes as a critical recharge source for the Ogallala aquifer. Playas filter and recharge as much as 95 percent of the water collected in the southern portion of the aquifer. Recharge occurs both through playa basins and along the perimeter (or annual rings) of playas. Recharge occurring through playa basins flows downward through large cracks in the clay lining. These cracks eventually swell shut and become impermeable as the clay absorbs water following a rain. Recharge occurring along playa perimeters takes place after rainfall events leave flood-water standing outside the clay-lined basins. Because of their role in recharging the Ogallala, the conservation of playas is as important to humans as it is to wildlife.
Conservation of playas
Several conservation practices benefit playa lakes. The most common is establishing native prairie buffers around the perimeter of playa basins. As shown in the photograph to the right. Grassland buffers slow or halt sedimentation. Their effectiveness largely depends on their size. Larger buffers are more effective at reducing sedimentation. Buffers also provide nesting habitat for grassland birds and forage and cover for other prairie wildlife. Fencing playa basins is another good conservation practice. Fences allow ranchers to limit livestock access to playas during the growing season. This allows for growth and establishment of plants that are beneficial to wildlife. Additionally, removing sediments and filling pits in order to restore playas basins holds promise, but these practices have only been attempted on a few playas and can be expensive.
The U.S. Fish and Wildlife Service, the U.S.D.A. Natural Resources Conservation Service (NRCS), and the Playa Lakes Joint Venture all have cost-share funds available to assist private landowners (and in some cases municipalities) with playa conservation. To find out more or to get technical assistance for playa conservation contact Bill Johnson, Texas Parks and Wildlife Department, PO Box 659, Canyon, Texas 79015 (806-651-3014) or your local NRCS representative.