No abstract

Highlight White-tailed deer were primarily grazers, rather than browsers, during the winter-spring periods of 1963, 1964, and 1965, in South Texas. There were only minor differences in distribution of major forage classes in deer diets from distinct range site groups, but major differences existed in species composition of diets in relation to site. Complexity of diet reduced the importance of any one or several species in the diet. Among high priority forage species, perennials were more important than annuals. Deer food habits varied according to availability and phenology of range vegetation, and were further modified by forage preferences. Major emphasis in management of South Texas rangeland has been directed toward sustained production of domestic livestock. Much of the same rangeland also supports substantial populations of white-tailed deer (Odocoileus virginianus Boddaert). This dual use of rangeland compounds management problems (Glazener, 1958). The preferred and most-used foods of each class of grazing animal in a given locality must be known as a basis for sound management of common-use ranges. Previous studies have shown that deer in the South and Southwest are primarily browsing animals, except during late winter and early spring when there is usually an increase in utilization of grasses and forbs (Hahn, 1945; Davis, 1952; Goodrum and Reid, 1954; 'CYhite, 1961; McMahan, 1964). Similar trends have also been noted in other regions (Chapman, 1939; Korschgen, 1962). McMahan (1964) reported that forbs appeared to be of greater importance in deer diets in the Texas Edwards Plateau region than generally believed. In South Texas, Davis (1952) reported that total consumption and diet of deer on the King Ranch followed the annual progression of plant growth l Contribution No. 115, Welder Wildlife Foundation,

Microhistological analysis of feces from Spanish goats (Capra hircur) grazing in a mixed-brush complex in the South Texas Plains indicated that shrubs were their major foods during autumn, winter, and summer. Grasses were the major diet item during spring. Forbs, which were relatively scarce due to poor growing conditions during the U-month study, were of minor importance in goat diets. The importance in Spanish goat diets of several problem brush species, including blackbrush acacia (A cacia rigidula), condalias (Condalia spp.), guajillo (Acaeio bertimdieri), guayacan (Porliera angust~ofia), and wolfberry (Lycim berlandini) suggests a potential for utilizing these animals in conjunction with other brush management practices for more effective shrub control and for increasing efficiency of forage utilization on mixed-brush rangeland.The South Texas Plains are approximately 8 million ha which historically supported grassland or Savannah type vegetation (Thomas 1975). Long-term continuous grazing, periodic droughts, and the reduced frequency and intensity of fires have resulted in a

Aerial applications of pelleted tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N, N′-dimethylurea} at 1 kg/ha to rangeland reduced canopy cover of the subshrub false broomweed (Ericameria austrotexanaM.C. Johnst.) by 69 to 78%. Complete control was obtained with 2 kg/ha of tebuthiuron. Picloram (4-amino-3,5,6-trichloropicolinic acid) pellets applied at 2 kg/ha controlled false broomweed in two of four experiments; effectiveness of soil-applied picloram appeared to depend upon sufficient rainfall to move the herbicide into the soil soon after treatment. After the first growing season following application, density of herbaceous species tended to be higher in plots receiving either herbicide than in untreated plots. Picloram suppressed curlymesquite [Hilaria berlangeri(Steud.) Nash], but had little effect on other components of the herbaceous vegetation. Abundance of curlymesquite increased substantially following applications of tebuthiuron, at the expense of annual and short-lived perennial grasses and herbaceous broadleaf species.

The effects of a 2—year drought on native grasses in South Texas were investigated on the Welder Wildlife Foundation Research Area during the summer of 1963. The percentage mortality on Victoria clay, Nueces fine sand, and Miguel find sandy loan was determined for seacoast bluestem (Andropogon scoparius Michx. var. littoralis (Nash) Hitch.), silver bluestem (Andropogon saccharoides Swartz var. longipaniculata Gould), filly panicum (Panicum filipes, Scribn.), buffalograss (Buchloe dactyloides (Nutt.) Engelm.), Pan American balsamscale (Elyonurus tripsacoides Humb. and Bonpl.), and brownseed paspalum (Paspalum plicatulum Michx.). Mortality ranged from an average low of 3407% for silver bluestem on Victoria clay to an average high of 76.8% for seacoast bluestem on Miguel fine sandy loam. Differences in percentage mortality between soils and between species on given soil types were highly significant. Mortality among individual clones ranged from 0% to 100%. In some instances a significant positive correlation existed between size of grass clones and percentage mortality. As diameter of clones increased, percentage mortality increased.

No abstract