Deer, Brush Control, and Livestock on the Texas Rolling Plains

GENE W. DARR AND DONALD A. KLEBENOW

Highlight: White-tailed deer (Odocoileus virginianus) were observed by the first year and another transect was spotlight in the Rolling Plains of Texas to determine deer use of habitats and added during the second year, how deer were influenced by brush control practices and grazing by livestock. increasing the total length of sample Deer densities were greatest in the bottomland habitat. The sand shinnery oak lines to 80 miles. Each transect was habitat, the mesquite-juniper redland habitat, and the sandyland ecotone habitat sampled twice each season for 2 years. supported moderate densities of deer. Influence of deer use from brush control The seasons of the year were practices varied in each habitat. Chaining bottomland habitat was detrimental to considered to be three-month periods deer: the larger the area chained, the lower density of deer it contained. with June, July, and August the Herbicides had little detrimental effect and in some situations may have been summer season, September, October, beneficial. Grazing by sheep was negatively related to deer densities except in and November as fall, and so forth. the bottomland habitat. In mesquite-juniper redlands and mimosa-erioneuron Spotlight observations were uplands, replacing sheep with cattle should increase deer populations. standardized according to recommendations suggested by Progulske and Duerre (1964), i.e., Many woody plants of low value improve ranges for livestock spotlighting was restricted to a 4-hour for cattle production have increased production. They realize white-tailed period, beginning 1 hour after sunset, on an estimated 82% of Texas deer are also an important range and nights with precipitation or bright grasslands (Smith and Rechenthin, product. Little is known of deer moonlight were avoided. The 1964). Consequently, numerous habitat preference and the influence spotlights were 13-volt small aircraft techniques to reduce brush have been from brush control and grazing landing lights operated with a 12-volt truck battery. Vehicle speed was developed (Carter, 1958). practices in this area, therefore, our maintained at approximately lo- 12 While some research (Box, 1964; research objectives were: (1) to obtain mph. Counts were made on both sides quantitative data on habitat use by Davis and Winkler, 1968; Goodrum of the transect from the bed of a and Reid, 1956; Reynolds, 1964) white-tailed deer during all seasons, (2) pick-up truck. When a deer was seen, a suggests that management for livestock to determine how existing brush record was made of the transect forage that includes brush control may control practices influence deer use of location (to the nearest 0.1 mile) and conflict with deer production, other habitats, and (3) to evaluate the the habitat in which it occurred. A workers (Blakey, 1947; Box and impact of class of livestock on habitat detailed evaluation of the census Powell, 1965; Bramble and Byrnes, use by deer. method was included in Darr’s thesis 1967; Krefting and Hansen, 1969) (1971). Transect widths were determined report instances where brush control Methods practices have been beneficial to deer. by measuring the distance from the The ranch chosen for a study area vehicle to the point where the lower In the Rolling Plains of Texas, was approximately 200 square miles in half of a person walking at right angles ranch managers recognize the need to size, located in the Texas Rolling to the transect could no longer be Plains as described by Thomas (1969). seen. In this area the deer are The authors were research assistant and Habitat use by white-tailed deer was approximately of waist height. Hahn assistant professor in the Department of determined by making spotlight ( 1949) reported using a similar Range and Wildlife Management, Texas Tech University, Lubbock. Present addresses counts on transects that were each method for determining widths of are: 200 Rebecca, No. 55, Bryan, Texas, approximately 20 miles in length. transects, but he included a white flag and Renewable Resources Center, University of Nevada, Reno. Three transects, or 60 miles of line, placed in the hip pocket of the person Manuscript received June 10, 1974. were run during each sampling period walking from the line. Ten samples of

JOURNAL OF RANGE MANAGEMENT 28(2), March 1975 115 transect width were taken in each of the seven habitat types. Stratifying the transects into habitat types and determining visibility in each type should meet the criteria for this type of strip census (Robinette et al., 1974). Additional information on summer use of habitat was provided by 1.5-hour observations made at sunrise or sunset at various times each summer. Observations were made from locations allowing a view of large areas. The vegetation was described by selecting two sites for analysis in each habitat type. Brush composition, canopy cover, and heights by species were determined by measurement of brush canopy along five randomly located line transects, each 50 ft long. Ocular estimates of the canopy cover of grasses and forbs, bare ground and litter, and the understory species frequency were recorded from 10 randomly located 16-inch square quadrats. At each site, samples were replicated four times. Taxa occurring iZ4 SANDYLAND ECOTONE at a sample site but not occurring in a m BOTTOMLAND &%I UPLAND SAVANNA quadrat or intercepted by a transect were listed. Scientific and common plant names are from Correll and Johnston (1970) and Gould (1969). Few areas on the ranch had not Fig. 1. Distribution of habitats on the Renderbrook-Spade Ranch, located in the Rolling been treated to reduce woody plains of Texas. vegetation. Previous brush control treatments were recorded wherever on the ranch (Table 2). Density here they occurred so that their effect upon inches with an average daily maximum temperature in summer of 97’F deer density could be determined. was four or fives times greater than in (Stoner et al., 1969). Areas sprayed in 1966 or earlier were the poorest habitats-the assumed to have recovered brush The soils in the area ranged from mimosa-erioneuron upland and the density to the point where treatments silty clay loam on the uplands to upland savanna. In the bottomland effects could not be neasured and heavy clays in the bottomlands. Eolian habitat the shrub canopy cover was these were combined and used as sands had been deposited near and east quite diverse (Table 1) and this may controls. Livestock grazing practices of the Colorado River. Diversity in have been attractive to the deer. Also, were also recorded. soils has led to a diverse vegetation. this habitat was widely distributed in a Statistical analyses (P = 0.05) were Herbicide sprays were first used on dendritic pattern that interspersed made using paired comparisons with t the ranch in 1940 to reduce the test and one-way analysis of variance density of brush. Since then, chaining with many other habitats (Fig. 1). It with Duncan’s new multiple range test and cabling were used in addition to was available for use by most deer on (Steel and Torrie, 1960). herbicides. The principal herbicide the ranch. used on the ranch was 2,4,5-T Deer densities ranked second in the (2,4,5-trichlorophenoxyacetic acid). sand shinnery oak habitat despite low Study Area Major habitats included bottomland vegetation that provided little mesquite-juniper redlands The study area was within the (13%), concealment for deer. Use is possibly (42%), sand shinnery oak (4%), Renderbrook-Spade Ranch, located 20 related to the importance of oak sandyland ecotone miles south of Colorado City in (4%), browse and acorns for food items. mimosa-erioneuron upland (18%), and west-central Texas. The topography Many authors (Hahn, 1945 ; upland savanna (19%) (Fig. 1). was nearly level to undulating, but Chained areas in the bottomland were Duvendeck, 1962; Segelquist and with steep slopes in areas of short, treated as a separate habitat for Green, 1968; Segelquist et al., 1969; rough breaks along the Colorado River vegetative analysis and all habitats are Short et al., 1969) reported their and the tributaries that dissected the described in Table 1. significance. On this same ranch in area. The semiarid climate was 1968, 24 rumen samples were characterized by low rainfall t’hat Results and Discussion collected during November and occurred as sporadic and intense December and sand shinnery oak Habitat Use thundershowers, high evaporation, and ranked third in the diet, providing 11% extremes in temperature. Average The unchained bottomland habitat of the total volume of food items annual precipitation has been 19.79 contained the highest density of deer (Klebenow, 1969).

116 JOURNAL OF RANGE MANAGEMENT 28(2), March 1975 Table 1. Descriptions of the major habitats on the RenderbrookSpade Ranch, Texas.

Canopy cover Habitat Vegetative characteristics Dominant brush species (%) Bottomland Canopy cover shrubs 20%, grasses 31%, Desert sumac (Rhus 6 Unchained forbs 17%. Contained tree species microphylla) Flat river and stream terraces such as little walnut (Jugkzns micro- Agarito (Berberis trifokta) 3 and alluvial fans, sometimes mrpa) and netleaf hackberry (Celtis Netleaf hackberry 2 hummocky with frequent reticulata). One-seeded juniper 2 gullies and sinkholes. Water (Juniperus monosperma) table high, occasionally Lotebush (Ziziphus ebtusfoltz 2 forming pools in dry stream Chained beds Canopy cover shrubs 4%, grasses 30%, Honey mesquite (Prosopis 2 forbs 16%. All regrowth less than 3 ft gland&w) var. glandulosa height.

Mesquite-juniper Soils clayer in texture and Canopy cover shrubs 19%, grasses 17%, One-seeded juniper 9 redland reddish in color. Located forbs 9%. Honey mesquite 6 above the alluvial bottom lands. Slope varies greatly usually gentle near bottom- lands, becoming steeper in upland areas. Sometimes steeper than 50 degrees. Some sites eroded, denuded of vegetation and topsoil, exposing layers of shale and interbedded clay.

Sand shinnery Soil deep Tivoli fine sand. Canopy cover shrubs 8%, grasses 18%, Sand shinnery oak oak Topography undulating to forbs 14%. Sand shinnery oak (Quercus gently sloping. Occasional havardii) less than 18 inches height dunes. broken by occasional motts of shin oak.

Sandyland Soil Brownfield fine sand Canopy cover shrubs 8%, grasses 13%, Honey mesquite 6 ecotone usually about 26 inches deep forbs 13%. Contained a gradient of One-seeded juniper over a subsoil of red to species between the sand shinnery oak Catclaw (Am&z greggii) yellow-red clay loam. habitat and the mesquite-juniper red- Borders the sand shinnery land habitat. oak habitat.

Mimosa- Steep to gently sloping breaks. Canopy cover shrubs 4%, grasses 25%, Catlaw mimosa (Mimosa 2 erioneuron Adjacent to and lower in forbs lo:%. Most shrubs (50%) less biuncifera) upland elevation to the upland than 3 ft height. Agarito 1 savanna. The slopes contain rounded fragments and con- cretions of caliche abundant on the surface. Water erosion is a hazard as vegetation is sparse.

Upland savanna Smooth, nearly level upland Canopy cover shrubs 3%, grasses 35%, Honey mesquite 3 plains, approximately 200 ft forbs 10%. Contained dense growth above the Colorado River of tobosa grass (Hilarli2 mutim) and bottomland. low growing honey mesquite (3-6 ft).

Daytime observations in the sand oak habitat type. important than was indicated by shinnery oak habitat indicated few The mesquite-juniper redland spotlight sampling. The sandyland deer were present. Occasionally they habitat only supported about half as ecotone bordered the sand shinnery could be flushed from dense oak motts many deer per 100 acres as the oak habitat and provided important and the presence of abundant deer bottomland and sand shinnery oak daytime cover for deer. Deer were fecal matter and bedding sites in motts types. Although total brush canopy observed to move from the sand indicated motts were important for cover was similar to the bottomland shinnery oak type into this habitat at cover. Visual observations at sunrise habitat, there was less diversity in dawn. The number of deer flushed found the deer moving into the oak shrubby vegetation and forb cover was while working in this habitat type motts or the more dense brushy areas less dense. We assume these habitat during daylight hours suggested our in adjacent habitats. The presence of features partially explain the lower spotlight samples contained a bias. oak motts and the proximity of number of deer found in this habitat. Work in other habitat types did not adjacent habitats with adequate cover The sandyland ecotone habitat also lead to a similar suspicion. were probably major factors that contained a moderate density of deer. The low numbers of deer favored deer use of the sand shinnery However, this habitat may be more consistently observed in the

JOURNAL OF RANGE MANAGEMENT 28(2), March 1975 117 Table2. Density of white-tailed deer in had a marked influence on the deer. deer were observed on these open the major habitats on the Renderbrook- Large chained bottoms approximately areas during daylight hours. We Spade Ranch, June 1969-June 197 1. 2 miles wide had 3 deer/100 acres suspect white-tailed deer were utilizing Deer/l 00 acres while those 1 mile wide had 11 the mesquite-juniper redland areas Habitat’ of habitat deer/ 100 acres. Davis and Winkler during the day for the cover it Upland savanna 3x (1968) found few deer crossing the provided but frequented the more Mimosa-erioneuron upland 4x middle of rootplowed areas. preferred feeding areas at night. Sandyland ecotone 6y Mesquite-juniper redland The effects of brush control with 7y Livestock vs Deer Density Sand shinnery oak 14 herbicides upon deer densities were Unchained bottomland 17 obscure. When sprayed areas were Conflicting results were obtained ’ All habitats except the sand shinnery oak compared to a control grazed with the when deer densities in bottomlands were sprayed in 1966 or earlier and grazed same class of livestock in the by cattle. The sand shinnery oak habitat grazed by sheep versus those grazed by was sprayed in 1969. bottomlands, there were lower cattle were compared to the XyValues with similar letters are not signifi- densities on the sprayed but not all mesquite-juniper redland and cantly different (P< 0.05). differences were significant (Table 3). mimosa-erioneuron habitats. The deer Results in the mesquite-juniper numbers were greater on sheep-grazed mimosa-erioneuron and upland redland were variable with both the bottomlands. With one exception, deer savanna habitat types are attributed to highest and lowest densities occurring densities were lower on sheep-grazed lack of cover and food. Deer use of the habitats that had been sprayed. In mesquite-juniper redlands and both these habitats appeared to be the sandyland ecotone the deer were mimosa-erioneuron upland habitats greater where they were interspersed nearly four times more abundant on than when these habitats were grazed with other habitats. the sprayed area than on the control. by cattle. The exception was the area In the mimosa-erioneuron upland and in the mesquite-juniper redland that Brush Control vs Deer Density upland savanna no significant we discussed above and believe was Brush control by chaining affected differences occurred in sprayed nearly vacated by deer at night when the number of deer an area contained habitats versus the controls when class the deer moved to adjacent feeding (Table 3). In the bottomlands the of stock was considered. areas. lowest densities of deer were in the Inspection of brush in aerially The mesquite-juniper redland, chained areas. These areas lacked cover sprayed habitats indicated that mimosa-erioneuron upland, and and deer were observed moving to and herbicides reduced canopy cover only bottomland habitat grazed by sheep from the chained areas in the evening by top-killing honey mesquite. The were all located in the same pastures. and early mornings. They retreated to root systems generally remained alive We suspect that competition from non-chained adjacent habitats for the and resprouting occurred. The sheep in the mesquite-juniper redland day just as they did in the study resprouted mesquite, plus many dead and mimosa-erioneuron upland reported by Davis and Winkler (1968). stems and branches, and other habitats forced deer into the most When moving to and from or within vegetative growth appeared to provide favorable deer habitat in the pastures, chained areas, deer utilized any satisfactory cover for white-tailed the bottomland habitat. The cause concealment available, mainly clumps deer. appeared to be forage depletion in the of woody vegetation or drainageways In the mesquite-juniper redland, the poorer redland and upland areas while in the area. These travel lanes were stand sprayed in 1969 and grazed by the bottomlands were still producing used by deer although several hundred cattle had a very low deer density. adequate forage for deer and sheep. yards of travel could have been This stand was a narrow strip Competition for forage between deer eliminated by a more direct route. approximately 80 yards wide between and livestock becomes much more Few deer ventured far into chained cultivated land and the sand shinnery intense during drouths (Merrill, 1957) areas where little or no cover existed oak habitat. Spotlight sampling and precipitation in 1970 (12.5 and most deer tended to remain near indicated that deer frequented these inches) was well below the annual the edge. The width of a chained area adjoining sites at night, although few average of 19.79 inches. McMahan (1964) reported that white-tailed deer Table 3. Density (number/100 acres) of white-tailed deer in the major habitats on the feeding habits closely resembled those RenderbrookSpade Ranch as affected by brush control and livestock grazing, June 1969- of sheep and that they compete for June 1971. forage. He noted that white-tailed deer tended to abandon pastures stocked with sheep. While the Renderbrook-Spade deer did not Control’ /Cattle 17XY 7 6 4x 3x abandon the pastures, they appeared Control’ /Sheep 23 4 1y 2x to retreat to the more productive 1967 Chain/Cattle 82 bottomland habitat even though sheep 1970 Chain/Cattle 10Z also utilized those areas. 1968 Spray/Cattle 14y 13 4x 3x 1968 Spray/Sheep 4x 1969 Spray/Cattle 0.3x 22 Conclusions 1970 Spray/Sheep 19x 2x 1y 1X 1 Treatments designated as controls were sprayed in 19 66 or earlier. Brush control should be coupled XyZValues with similar letters within each column are not significantly different (P< 0.05). with deer management on a habitat

118 JOURNAL OF RANGE MANAGEMENT 28(2), March 1975 basis. The bottomlands and sand marked effect on deer use of a habitat. Hahn, H. C., Jr. 1949. A method of shinnery oak habitats had the highest Since grazing by sheep appeared to be censusing deer and its adaptation in the Edwards Plateau of Texas. Texas Game, densities of deer on the ranch and any detrimental to deer, the relative values Fish, and Oyster Comm. 24 p. brush control program in these areas of one resource versus the other Klebenow, D. A. 1969. The food of the should be carefully considered. should be considered. Pastures grazed white-tailed deer on the Rolling Plains. White-tailed deer densities in the by sheep in the mesquite-juniper Noxious Brush and Weed Control Res. mesquite-juniper redland habitat were redlands and mimosa-erioneuron Rep., Texas Tech Univ., Lubbock. Spec. Rep. No. 33:67-69. moderate, but considerations for deer uplands had lower deer densities than h eft. mg, L. W., and H. L. Hansen. 1969. are important especially since the those grazed by cattle. Since these Increasing browse for deer by aerial mesquite-juniper redland habitat was habitats occupy approximately 65% of applications of 2,4-D. J. Wildl. Manage. the predominate habitat.on the ranch the ranch, sheep numbers should be 33:784-790. McMahan, C. A. 1964. Comparative food and thus contained a considerable manipulated according to the desired habits of deer and three classes of number of deer. Brush management in population level of deer. livestock. J. Wildl. Manage. 28:798-808. the mimosa-erioneuron upland and Merrill, L. B. (Chairman). 1957. Livestock upland savanna habitats would not be Literature Cited and deer ratios for Texas rangelands. of great significance to deer since these Texas Agr. Exp. Sta. Bull. MP-221. College Station. 9 p. habitats received minor white-tailed Blakey, H. L. 1947. The role of brush control in habitat improvement on the deer use. Aransas National Wildlife Refuge. Trans. Progulske, D. R., and D. C. Duerre. 1964. Fat t ors influencing spotlighting counts Chaining removed canopy North Amer. Wildl. Conf. 12: 179-185. of deer. J. Wildl. Manage. 28:27-34. vegetation that provided cover for Box, T. W. 1964. Changes in wildlife habitat composition following brush control Reynolds, H. G. 1964. Elk and deer habitat white-tailed deer, and deer densities practices in South Texas. Trans. North use of a pinyon-juniper woodland in were less on chained bottomlands. Amer. Wildl. Conf. 29:432-438. southern New Mexico. Trans. North Deer used chained areas but the Box, T. W., and J. Powell. 1965. Brush Amer. Wildl. Conf. 29:438-444. Robinette, W. L., C. M. Loveless, and D. A. densities declined with distance from management techniques for improved forage values in South Texas Trans. Jones. 1974. Field tests of strip census Chaining would be adequate cover. North Amer. Wildl. and Natur. methods. J. Wildl. Manage. 38:81-96. most compatible if smaller areas were Resources Conf. 30:285-296. Segelquist, C. A., and W. E. Green. 1968. treated and strips and clumps of Bramble, W. C., and W. R. Byrnes. 1967. Deer food yields in four Ozark forest woody vegetation were left to provide Ecological aspects of brush control-a types. J. Wildl. Manage. 321330-337. travel lanes and escape cover for deer. long term study on a utility right-of-way. Segelquist, C. A., F. D. Wards, and R. G. Purdue Univ., Agr. Exp. Sta. Res. Bull Leonard. 1969. Habitat-deer relations in Aerial spraying of herbicides should 8 35. Lafayette, Indiana. two Ozark enclosures. J. Wildl. Manage. be coordinated with white-tailed deer Carter, M. G. 1958. Reclaiming Texas 33:5 1 l-520. habitat improvement in the brushland range. J. Range Manage. Short, H. L., C. A. Segelquist, P. D. mesquite-juniper redlands, the sandy ll:l-5. Goodrum, and C. E. Boyd. 1969. Cornell, D. S., and M. C. Johnston. 1970. ecotone, and the bottomlands. Rumino-reticular characteristics of deer Manual of vascular plants of Texas. on food of two types. J. Wildl. Manage. Herbicides presently being used gave George Banta Company, Inc. Menasha, 33~380-383. effective kills only on top growth of Wisconsin. 188 1 p. Smith, H. N., and C. A. Rechenthin. 1964. honey mesquite. The dead tops and Darr, G. W. 1971. White-tailed deer habitat Grassland restoration-the Texas regrowth from the roots still provided in the Texas Rolling Plains. MS Thesis, problem. U.S. Dep. Agr., Soil Conserv. Texas Tech Univ., Lubbock. 73 p. cover for the deer. This effect could Service, Temple, Texas. No. Davis, R. B., and C. K. Winkler. 1968. Brush 4-19114:1-10. change, however, if development and vs. cleared range as deer habitat in South Steel, R. G. D., and J. H. Torrie. 1960. use of more effective herbicides or Texas. J. Wildl. Manage. 32:321-329. Principles and procedures of statistics. persistent use of present herbicides Duvendeck, J. P. 1962. The value of acorns McGraw-Hill Book Company, Inc., New should eventually remove the brush. in the diet of Michigan deer. J. Wildl. York, 481 p. Manage. 26:371-379. Stoner, H. R., T. J. Holder, D. L. The results could be the same as Goodrum, P. D., and V. l-L Reid. 1956. McCiennen, and K. M. Templeton. 1969. chaining. Wildlife implications of hardwood and Soil survey of Mitchell County, Texas. brush control. Trans. North Amer. Wildl. U.S. Dep. Agr., Soil Conserv. Service, Oak motts in the sand shinnery oak Conf. 21:127-141. and Texas A and M Univ., College habitat should not be removed because Gould, F. W. 1969. Texas plants-a checklist Station. 47 p. they are critical for deer use of this and ecological summary. Texas A and M Thomas, G. W. 1969. Texas plants-an habitat. Brushy areas in habitats Univ. and Texas Agr. Exp. Sta. MP-585 ecological summary. p. 7-14. In F. W. (revised). College Station. 221 p. Gould. Texas plants-a checklist and adjacent to the sand shinnery oak Hahn, H. C., Jr. 1945. The white-tailed deer ecological summary. Texas A and M habitat should also be left for cover. in the Edwards Plateau region of Texas. Univ. and Texas Agr. Sta. MP-585 The kind of livestock can have a Texas Game, Fish, and Oyster Comm. 52 p. (revised). College Station. 221 p.

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