In lieu of an abstract, here is a brief excerpt of the content:

184 Bobwhites on the Blackland Prairies Markus J. Peterson This [blackland] prairie has been largely converted to farmland, although a few relicts remain in wildlife habitat and on ranches. Sims and Risser (2000) The Blackland Prairies physiographic region of Texas (figure 10.1) is not currently thought of as prime quail country, although northern bobwhites (Colinus virginianus) certainly occur there. Rich blackland soils, however, once supported substantial numbers of bobwhites (Texas Game, Fish and Oyster Commission [TGFOC] 1945:46–60). In many ways, this ecological area serves as a useful microcosm for understanding bobwhite trends across Texas; abundance probably increased after European-American settlement, then decreased to levels where hunting could not be supported over much of the region. Both changes resulted from human activities. Lessons learned from the Blackland experience have direct relevance to today’s bobwhite strongholds, such as the Rolling Plains and South Texas Plains (Gould 1962). Thus, the purpose of this chapter is to briefly (1) describe the Blackland Prairies, (2) present historical trends in bobwhite abundance in this region—including their causes and possible futures, (3) explore relevant ecological relationships, (4) evaluate attempts to enhance bobwhite abundance in this region, (5) outline gaps in our knowledge about bobwhites in this ecoregion, and (6) summarize this material and outline management implications. Description of the Blackland Prairies The Blackland Prairies consists of about 5.1 million hectares (12.6 million acres)—including the San Antonio and Fayette prairies—and represents the southern extreme of the true prairie that once extended from Canada to Texas (Gould 1962:10; Hatch, Gandhi, and Brown 1990:7,12–13). Topography is nearly level to gently rolling and is well dissected with rapid surface drainage. Elevation varies from 76 to 213 meters (250 to 700 feet) above mean sea level. Because this region intermingles with the Post Oak Savannah in the south, some of the past bobwhite research conducted in this area (e.g., Parmalee 1952a) occurred on Blackland Prairies and Post Oak Savannah sites, although he referred to the entire study area as Post Oak Savannah. Average annual precipitation in the Blackland Prairies varies from 76 centimeters (30 inches) in the west to about 114 centimeters (45 inches) in the east (Carr 1969; Hatch, Gandhi, and Brown 1990:6–8). Precipitation is seasonally bimodal, with primary and secondary peaks in May and September , respectively. There are 230–280 frost-free days annually. Uplands in the Blackland Prairies are characterized by dark, calcareous , shrink-swell clayey soils, changing gradually with depth to light 10 Figure 10.1. The Blackland Prairie ecoregion of Texas. Courtesy Caesar Kleberg Wildlife Research Institute (CKWRI) GIS Laboratory marls or chalks (Hatch, Gandhi, and Brown 1990:12). Bottomland soils generally are reddish brown to dark gray, slightly acid to calcareous, loamy to clayey and alluvial. These soils are quite fertile, but many have lost productivity through erosion and continuous cropping. Hatch, Gandhi, and Brown (1990:12) maintained that “this onceluxuriant tallgrass prairie” previously was dominated by little bluestem (Schizachyrium scoparium), big bluestem (Andropogon gerardii), yellow indiangrass (Sorghastrum nutans), tall dropseed (Sporobolus asper), and Silveus dropseed (S. silveanus) (figure 10.2). Grasses, such as sideoats grama (Bouteloua curtipendula), hairy grama (B. hirsuta), Mead’s sedge (Carex meadii), Texas wintergrass (Stipa leucotricha), and buffalograss (Buchloe dactyloides), increased with grazing pressure. Common forbs include asters (Aster spp.), prairie bluet (Hedyotis nigricans), prairieclovers (Petalostemon spp.), and late coneflower (Rudbeckia serotina). Common legumes include snoutbeans (Rhynchosia spp.) and vetches (Viciaspp.).Oaks(Quercusspp.),elms(Ulmusspp.),cottonwoods (Populus spp.), and native hickories and pecans (Carya spp.) probably always were widespread along drainages. Mesquites (Prosopis glandulosa), huisache (Acacia smallii), oaks, and elms are common invaders on abandoned croplands and poor-condition rangelands. Approximately 98 percent of the Blackland Prairies was cultivated to produce cotton, sorghum, corn, wheat, and forage crops during the late nineteenth and early twentieth centuries (Hatch, Gandhi, and Brown 1990:12–13). After the drought of the 1950s, only about 50 percent of this physiographic region was used as cropland, with pasture and forage crops making up the difference. By 2001, 24 and 19 percent, respectively , of the total and nonurban area of the Blackland Prairies was used for crop production (Wilkins et al. 2003). Conversely, urbansuburban sprawl took up 23 percent of the Blackland Prairies, whereas 21 percent of the remaining rural lands were in tame pasture, primarily coastal bermudagrass (Cynodon dactylon). Other pasturelands still made up approximately 52 percent of nonurban landscapes in this region (40 percent of total) (Wilkins et...

Share