Going, Going, Gone: The impact of land fragmentation
on Texas agriculture and wildlife
More Ranchettes, Less Wildlife
The new landowners differ from their predecessors in another important way: They are typically two or three generations removed from any close ties to the land. Their values and ideas have been shaped by a lifetime in the city or suburbs. They may have little appreciation of how delicate their newly purchased hundred acres of heaven can be.
Many arrive with good intentions of doing some sort of wildlife management on their land. However, they often have little in the way of training or experience to back up those plans, and soon there is little wildlife left to manage. Sometimes it isn't what a particular owner does, but what his or her neighbor is doing that is the problem.
Much of the wildlife native to Texas requires vast areas of land to thrive, and the ranches of past generations provided suitable habitat. Cattle roamed relatively undisturbed lands eating what nature provided. Because ranches were surrounded by other ranches, most managed in the same low-impact manner, large tracts of native habitat were preserved.
As those properties are fragmented, that age-old pattern is disturbed, often with devastating results for wildlife. One owner may prefer a manicured setting, while his neighbor wants to let the land manage itself. Meanwhile, a couple of owners down the road may plant "improved" non-native pasture grass for their small herds of cattle or horses. Before long, what remains of the native habitat is splintered, and the animals that thrived there die off or move on.
This process has taken a particularly heavy toll on Northern Bobwhite quail. In the United States, the Northern Bobwhite population has declined by 66 percent—an annual rate of decline of 3.8 percent—between 1982 and 1999. To thrive, these tiny birds need huge amounts of land. A sustainable breeding population of quail (at minimum, about 800 birds) requires 5,000 acres of essentially unbroken rangeland. While the sustainability of this species in South Texas and the Rolling Plains appears promising—since these areas are dominated by land ownerships exceeding 2,000 acres each—such habitat has become hard to find in the central and eastern areas of the state. Most of the Pineywoods is comprised of land ownership areas less than 100 acres, with remaining areas east of I-35 averaging 100 to 500 acres.
Data analyzed by Texas A&M researchers indicate that as the size of landholdings decreases, the amount of "improved" pasture (non-native, exotic grasses such as coastal bermuda) increases. About 67% of the state's 10 million acres of "improved" pasture lie in the eastern 25 percent of the state where grassland-dependant wildlife species such as bobwhite quail have declined the most.
Over 20% of the Blackland Prairie, which was once prime quail habitat, is now in "improved" pasture mostly on small landholdings. During the 1990s, the Blackland Prairie lost an additional 180,000 acres of land to urbanization. Further east, in the Piney Woods, the amount of "improved" pasture grew by 425,000 acres— a jump of 30 percent in one decade. Those carpets of short, green grasses may be attractive to humans but have little to offer quail and other wildlife. Certainly, islands of good habitat remain in those regions and small populations of birds have hung on, but they are much more susceptible to being killed off by drought, predators and continued habitat degradation.
Today, east of I-35, the call of the quail has all but gone silent. Two dozen other species of grassland birds -- including the Eastern Meadowlark, Bachman's sparrow and the Loggerhead Shrike -- are also being driven out, along with many species of small mammals. Horned lizards, box turtles, various insects and many other creatures are also gone or disappearing. In many parts of that region, the delicate ecosystem that existed in balance for ages is lost.
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