@article {50329, title = {Volatile compounds on the leaf surface of intact and regrowth tarbush (Flourensia cernua DC) canopies}, journal = {Journal of Chemical Ecology}, volume = {33}, year = {2007}, month = {September 25, 20}, pages = {1867-1875}, abstract = {

Shrub expansion into desert grasslands is a serious problem resulting in loss of forage and rangeland productivity. Flourensia cernua DC (tarbush) is one such shrub contributing to the decline of Chihuahuan Desert grasslands. Our previous research has shown tarbush consumption by sheep and goats to be negatively related to leaf surface concentration of individual terpenes and epicuticular wax. Concentrations of compounds such as terpenes often change with plant age and phenology. Our objective was to examine the effect of altering the vegetative state of tarbush on volatile chemicals. Ninety tarbush plants were randomly selected and all biomass within 10 cm of the soil surface was removed from 45 plants during winter dormancy. Leaves were collected the following summer during active growth from the canopy of intact controls and resprouts. Leaf surface volatiles were analyzed by gas chromatography-mass spectroscopy and subjected to univariate analysis of variance and stepwise discriminate analysis. Of the 87 compounds present on tarbush leaves, 35 were greater in canopy samples and 16 were greater in regrowth samples based on univariate analysis (P\< 0.05). Mean concentration of total volatiles on canopy leaves tended to be less (P = 0.062) than that of regrowth (3642 vs. 4684 {\`\i}g/g DM). Nine compounds in the discriminant analysis ({\'a}-muurolene, iso-borneol, unknown$\#$6, p-cymen-8-ol, unknown$\#$7, sabinene, {\^a}-caryophyllene, {\"a}-cadinene, and {\'a}-copaene) explained 95\% of the variation between canopy and regrowth samples. Lower cumulative concentration of volatile compounds in canopy than regrowth samples suggests repsrouts may be less vulnerable to herbivory than intact tarbush.

}, keywords = {Flourensia cernua, plant secondary metabolites, regrowth, tarbush, terpenes}, doi = {10.1007/s10886-007-9360-8 }, url = {/files/bibliography/07-029.pdf}, author = {E.L. Fredrickson and Richard E. Estell and M.D. Remmenga} } @article {50380, title = {Jackrabbit (Lepus californicus) herbivory changes dominance in desertified Chihuahuan Desert ecosystems.}, journal = {Journal of Arid Environments}, volume = {70}, year = {2007}, month = {03/2007}, pages = {418-426}, abstract = {This study addressed the question: can herbivory by a medium size herbivore, black-tail jackrabbits (Lepus californicus), change dominance in desertified ecosystems dominated by two species of shrubs. Shrubs that were pruned by jackrabbits in plant communities dominated by creosotebush (Larrea tridentate) and tarbush (Flourensia cernua) were compared to shrubs not browsed by the rabbits. In the missed shrub area, herbivory on F. cernua resulted in death of 46.6\% of the shrubs, compared to only 4.8\% of L. tridentate shrubs. There was no evidence of jackrabbit browsing of dead F. cernua in a tarbush monoculture area. The canopy volumes of F. cernua plants that survived repeated browsing were significantly smaller than predicted based on unbrowsed plants with the same basal stem areas. Jackrabbit browsing resulted in increased canopy volume of creosotebush shrubs. Creosotebush average canopy volume significantly exceeded predicted values because of compensatory growth of stems from nodes below the severed point. Close spatial association of lightly browsed creosotebush with heavily browsed tarbush may be a factor contributing to low utilization of creosotebush stems by jackrabbits. Differential browsing by the rabbits is shifting thee ecosystems toward an L. tridentate monoculture.}, keywords = {browsing, compensatory growth, creosotebush, Flourensia cernua, Larrea tridentata, preferential feeding, tarbush}, doi = {10.1016/j.jaridenv.2007.01.009}, url = {/files/bibliography/07-016.pdf}, author = {Roth, G.A. and Walter G. Whitford and Yosef Steinberger} } @article {50567, title = {Loss of phenolic compounds from leaf litter of creosotebush [Larrea tridentata (Sess. \& Moc. ex DC.) Cov] and tarbush (Flourensia cernua DC.)}, journal = {Journal of Arid Environments}, volume = {61}, number = {1}, year = {2005}, month = {April 1, 2005}, pages = {79-91}, abstract = {We examined loss of organic matter and phenolics from leaf litter of two shrubs that are invasive in the Chihuahuan Desert. Fiberglass bags (1-mm mesh) containing creosotebush [The objective of this paper is to provide insights into exotic and native invasive species dynamics using a conceptual model developed from the long history of research on native woody plant invasion into perennial grasslands. We first describe our new conceptual model that focuses on landscape characteristics (spatial configuration and connectivity) interacting with environmental drivers and biotic processes across multiple scales. We then provide support for the model using a long-term dataset from southern New Mexico. Finally, we discuss new insights this model has to offer for understanding, predicting, and managing exotic invasive species dynamics. (Sess. \& Moc. ex DC.) Cov.] or tarbush (Flourensia cernua DC.) leaf litter were placed below shrubs in two positions (soil surface and 5 cm belowground) and removed at several intervals up to 90 days during winter (creosotebush and tarbush) and spring (creosotebush). Over the 90-day sampling interval, organic matter loss from creosotebush and tarbush during the winter sampling period was low for both surface and buried litter, ranging from 1.7-5.2\%. Losses of organic matter from creosotebush litter during the spring were much greater (75.1 and 33.5\% for buried and surface samples, respectively). Total phenolic losses after 90 days were 1.6, 4.8, 21.6, 13.5, 87.1, and 43.5\% for winter buried creosotebush, winter surface creosotebush, winter buried tarbush, winter surface tarbush, spring buried creosotebush, and spring surface creosotebush litter, respectively, while losses of condensed tannins for the same samples were 45.8, 56.1, -34.0, -41.8, 91.1, and 67.4\%. Nordihydroguaiaretic acid loss from creosotebush litter was 25.4, 18.3, 95.2, and 66.7\% for winter buried, winter surface, spring buried, and spring surface samples, respectively, over the 90-day interval. Losses of organic matter and phenolics were generally greater in buried vs. surface and spring vs. winter samples, and losses typically occurred during the last 30-45 days. http://www.sciencedirect.com/science?_ob=MImg\&_imagekey=B6WH9-4DGW3YW-3-C\&_cdi=6845\&_user=1496926\&_orig=browse\&_coverDate=04\%2F01\%2F2005\&_sk=999389998\&view=c\&wchp=dGLbVlb-zSkzV\&md5=f5a61c1ff74b379cac3f662abc4550b3\&ie=/sdarticle.pdf}, keywords = {creosotebush, Flourensia cernua DC., Larrea tridentata, leaf litter, loss, organic matter, phenolics, tarbush}, url = {/files/bibliography/05-024.pdf}, author = {P.W. Hyder and E.L. Fredrickson and Richard E. Estell and M.E. Lucero and M.D. Remmenga} } @conference {51067, title = {Fluorensia cernua extracts decrease intake of alfalfa pellets by sheep}, booktitle = {2000 Joint Meeting, American Society of Animal Science/American Dairy Science Association}, volume = {78}, number = {Suppl. 1}, year = {2000}, month = {2000}, pages = {113}, publisher = {Journal of Animal Science}, organization = {Journal of Animal Science}, abstract = {

Our objective was to evaluate the effects of 3 extracts (hexane, ether and ethanol) isolated from tarbush on intake of alfalfa pellets by sheep. In each of 2 experiments, 45 ewe lambs received 1 of 5 treatments for 5 d. Treatments were alfalfa pellets (CON) or alfalfa pellets plus ethanol carrier (CAR), hexane extract (HEX), ether extract (ETH) or ethanol extract t(ETOH). Treatments were isolated from tarbush leaves (36 kg) using a sequential extraction of hexane, diethyl ether and 100\% ethanol. Extractions (3 kg of leaves in 7 L of solvent, constant mixing, 22 h per solvent) were filtered, solvents removed using a rotary evaporator and resuspended in ethanol. Lambs were offered 640 g of alfalfa pellets (DM basis) and intake was monitored during a 20-min interval each morning. Extracts were applied to alfalfa pellets at the same concentration as in tarbush in Exp. 1, and at 10-fold dilutions in Exp. 2. Lambs were adapted to handling and individual pen feeding for 10 d and maintained and fed alfalfa pellets (4.7\% of BW, DM basis) as one group except during 20-min tests. All 3 extracts reduced intake by lambs in Exp. 1 ( P \< .0001) compared to CON or CAR. Mean intake during the 20-min period was 361, 393, 204, 212 and 228 g for CON, CAR, HEX, ETH and ETOH, respectively (SEM=28.9). Intake did not differ between CON and CAR, nor among HEX, ETH and ETOH. Mean intake in Exp. 2 was not different (468, 455, 389, 381 and 431 g for CON, CAR, HEX, ETH and ETOH, respectively; SEM =30.5; P =.187). Three fractions containing mixtures of compounds of increasing polarity were equally effective in decreasing intake of alfalfa pellets at concentrations encountered in intact tarbush plants; thus, several compounds are probably involved in the low palatability of this shrub exhibited by livestock.

}, keywords = {alfalfa pellets, extracts, Fluorensia cernua, intake, sheep, tarbush, treatments}, author = {Richard E. Estell and M.R. Tellez and E.L. Fredrickson and D.M. Anderson and Kris Havstad and M.D. Remmenga} } @article {51071, title = {The effect of feeding ewe lambs a 15\% tarbush (Flourensia cernua DC) pellet pre- and post-weaning on the subsequent diet selection of tarbush}, journal = {Journal of Arid Environments}, volume = {44}, number = {1}, year = {2000}, month = {January 1, 2000}, pages = {123-131}, abstract = {

The shrub Flourensia cernua (tarbush) has rapidly increased in dominance within Chihuahuan Desert grasslands, and is comparable to alfalfa in nutrient density. Increasing tarbush in livestock diets may improve diet quality, while decreasing tarbush dominance. We determined dietary preference for tarbush by sheep and the effect of previous exposure on preference. Thirty-eight ewe lambs received either tarbush or alfalfa in sorghum-based pellet 120 days postparturition; after which, dietary preference was assessed. Previous exposure averted lambs from tarbush consumption. Lambs without previous exposure maintained greater intakes initially, but declined with time. This decline corresponds with onset of tarbush toxicosis.

}, keywords = {ewe lambs, Flourensia cernua, post-weaning, pre-weaning, tarbush}, doi = {10.1006/jare.1999.0571}, url = {/files/bibliography/00-003.pdf}, author = {E.L. Fredrickson and Richard E. Estell and Kris Havstad and Shupe, W. Larry and L. W. Murray} } @article {51385, title = {Tarbush leaf surface terpene profile in relation to mammalian herbivory}, journal = {Journal of Chemical Ecology}, volume = {24}, year = {1998}, month = {January 1998}, pages = {1-12}, abstract = {

Tarbush (Flourensiacernua DC.) is a generally unpalatable shrub native to the Chihuahuan Desert and with a resinous leaf surface containing several terpenes. Tarbush epicuticular wax concentration has previously been linked to degree of use by livestock in our laboratory. In 1989 and 1990, cattle, sheep, and goats were densely stocked in tarbush-containing paddocks for 6 to 9 days. Degree of use of 20 permanently marked plants in each paddock (8 paddocks, 2 sites, only 10 plants were monitored in 4 of the paddocks the first year) was recorded daily both years. Thus, no destructive sampling of plants was possible. A high percentage of tarbush in diets and differential use of individual tarbush plants were observed in this companion study. In 1991, leaves were collected from these plants (n = 160) during the same stage of maturity. Leaf surface compounds were extracted with ethanol, and mono- and sesquiterpenes were analyzed using gas chromatography/ion trap mass spectrometry. Our objective was to examine whether degree of tarbush use during the high-density study was related to chemistry of the same plants the following year. Plants were separated into three categories after preliminary data evaluation (Category 1: \> 50\% use at period midpoint; Category 2: \< 50\% use at midpoint but \> 50\% use at period end; Category 3: \< 50\% use at period end). Multivariate analysis is being used to examine relationships of individual plant use with dry matter, ash, epicuticular wax, and several individual and subgroups of mono- and sesquiterpenes (oxygenated and hydrocarbon monoterpenes and sesquiterpenes). Preliminary evaluation suggests chemical subgroup variables in 1991 were related to degree of herbivory in 1989 and 1990, although statistical analyses are not complete. Monoterpene hydrocarbons, oxygenated monoterpenes, and oxygenated sesquiterpenes were all sign different for the three use categories. We will determine which individual compounds contribute to these differences. Estimated concentrations of unidentified compounds will also be evaluated. One assumption is that heavy browsing during 1989 and 1990 did not cause plant secondary chemistry changes which persisted in 1991. Of the 120 plants with use data for both years, 66 plants in a given use category for 1989 were in the same category in 1990 and 38 plants were in a higher category. Only 15 plants fell to a lower use category and only 1 plant dropped from Category 1 to 3. Based on these observations, degree of use was reasonably consistent for individual plants across years, suggesting that, at least between 1989 and 1990, if induction occurred, it was short term. Leaf surface chemistry appears to be related to degree of use of individual tarbush plants by livestock.

}, keywords = {Chihuahuan Desert, leaf surface, mammalian herbivory, tarbush, terpene profile}, doi = {10.1023/A:1022399426352}, url = {/files/bibliography/512.pdf}, author = {Richard E. Estell and E.L. Fredrickson and D.M. Anderson and Kris Havstad and M.D. Remmenga} } @article {51439, title = {Effects of organic solvents on use of tarbush by sheep}, journal = {Journal of Chemical Ecology}, volume = {20}, number = {5}, year = {1994}, month = {1994}, pages = {1137-1142}, abstract = {

Tarbush (Flourensia cernua DC) is a native perennial shrub prevelant in many parts of the Chihuahuan desert. Ruminants have exhibited limited use of tarbus leaves and new leaders as a forage during the summer growing season. Efforts to increase use of tarbush by lambs, through spraying with various organic solvents were unsuccessful. probably because of the highly variable response. However, complete immersion of tarbush in organic solvents (acetone and ethanol) increased (P\< 0.01) tarbush use by ram lambs when compared to unaltered tarbush using organic solvents enhanced acceptability of tarbush to sheep.

}, keywords = {Flourensia cernua, herbivory, leaf surface, organic solvents, sheep, tarbush}, doi = {10.1007/BF02059749}, url = {/files/bibliography/416.pdf}, author = {Richard E. Estell and D.M. Anderson and Kris Havstad} } @article {51443, title = {Effects of chronic ingestion of tarbush (Flourensia cernua) on ewe lambs}, journal = {Veterinary and Human Toxicology}, volume = {36}, number = {5}, year = {1994}, month = {1994}, pages = {409-415}, abstract = {

Efforts to increase livestock utilization of tarbush are being coupled with studies to examine tarbush toxicity. Thirty-eight (19/treatment) ewe lambs were assigned at birth to receive either tarbush or alfalfa (15\%, dry matter basis) in a sorghum-based growing ration. Lambs were pen-fed this diet 60 d pre-weaning and 60 d post-weaning. No differences existed between treatments in feed consumption. In the tarbush group, 1 lamb died of unknown causes at 90 d of age, while 3 lambs died between 115 and 120 d of age. There were no deaths in the alfalfa group. Shortly before death, lambs fed tarbush appeared lethargic, disoriented and anorectic. At 122 d of age, 5 lambs were randomly selected from each group. Feces and jugular blood samples were obtained from each lamb before being euthanized and necropsied the following day. All fecal samples were negative for occult blood. Serum gamma glutamyl-transpeptidase (P\  \<\  0.001) and aspartate aminotransferase (P\  \<\  0.001) activities and platelet counts (P\  \<\  0.05) were elevated in lambs fed tarbush, while serum calcium concentrations tended (P\  \<\  0.10) to be greater. Histologic examination revealed diffuse liver apoptosis in lambs fed tarbush. These data indicate tarbush leaves cause liver damage when fed for extended periods of time.

}, keywords = {chronic ingestion, ewe lambs, Flourensia cernua, tarbush}, url = {/files/bibliography/421.pdf}, author = {E.L. Fredrickson and Thilsted, J.P. and Richard E. Estell and Kris Havstad} } @inbook {51449, title = {Rangeland cover types of the Southwestern Region: Creosotebush-Tarbush (SRM 508)}, booktitle = {Rangeland Cover Types of the United States}, year = {1994}, month = {1994}, pages = {67-68}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Denver, CO}, keywords = {cover types, creosotebush, rangeland, southwestern region, tarbush}, author = {C.H. Herbel}, editor = {Shiflet, T.N.} } @proceedings {52394, title = {Control of mesquite, creosotebush, and tarbush on arid rangelands of the southwestern United States}, year = {1970}, month = {1970}, pages = {38-41}, address = {Surfers Paradise, Australia}, abstract = {Sparse stands, up to 200 plants per ha, of mesquite, creosote bush and tarbush may be economically controlled with an individual plant treatment of fenuron pellets or other dry herbicides. Aerial spraying with 2, 4, 5-T is also an economical method of reclaiming mesquite-infested areas. The treatment also affords an excellent method of increasing production of perennial grasses.}, keywords = {aerial spraying, arid rangelands, control, creosotebush, fenuron pellets, mesquite, tarbush}, url = {/files/bibliography/125.pdf}, author = {C.H. Herbel and W. L. Gould} } @article {52409, title = {Herbicide evaluation studies for the control of tarbush (Flourensia cernua)}, year = {1969}, month = {1969}, pages = {27}, institution = {Research Progress Report, Western Society of Weed Science}, abstract = {

Tarbush is a deciduous desert species which is found in dense stands on silty or clay loam sites on flood plains. The date of leaf emergence is dependent upon adequate soil mosture, so in some droughty years it may not leaf out until the summer rains occur. The studies reported were carried out on the Jornada Experimental Range near las Cruces, New Mexico, from 1961 through 1965 to determine the best time for treatment and the best herbicides for selective control. Treatments were applied semi-monthly on 1/100 A plots using a simulated aerial application from July through October in 1961 and 1965. Treatments were initiated in August 1962, on May 7, 1963, and on June 3, 1964. Defoliation estimates were made approximately 2 years after treatments were applied. The 1961 treatments included 2,4-D, 2,4-DP, 2,4,5-T, silvex, 2,3,6-TBA and amitrole-T at 1/2 lb/A. Dicamba was added to the list of test materials in 1962 and picloram was added in 1963. Herbicides were applied on all spray dates at 1/2 lb/A in 1962, 1 lb/A in 1963 and 1 1/2 lb/A in 1964 and 1965. Additional treatments with higher rates of herbicides were applied on one spray date ind 1962, 1963 and 1964. The defgree of defoliation was quite variable between dates of application with the September treatments being most toxic generally. At rates up to 2 lb/A, the phenoxy herbicides and amitrole-T usually gave less than 30\% defoliation. Dicamba was the most toxic material, causing 70\% defoliation on one or more spray dates each year. Increasing the rate of dicamba from 1/2 to 2 lb/A increased the degree of defoliation only when treatment was not on the optimum date. At comparable rates, picloram and 2,3,6-TBA were much less effective than dicamba.

}, keywords = {control, evaluation, Flourensia cernua, herbicide, tarbush}, url = {/files/bibliography/113.pdf}, author = {W. L. Gould and C.H. Herbel} } @article {52466, title = {Tarbush [Flourensia cernua (DC.)]}, year = {1966}, month = {1966}, pages = {38 }, publisher = {U.S. Department of Agriculture and U.S. Department of the Interior, Chemical Control of Range Weeds, Interagency Report}, abstract = {Tarbush, a member of the composite family (sunflower tribe), is a common deciduous shrub, usually less than 3 feet tall, that grows on an estimated 13,250,000 acres from western Texas to southeastern Arizona. It generally invades on the more productive flood plain sites and spreads from seed. As it gains dominance, forage production is greatly reduced. Tarbush is practically worthless for browsing. Individual plant treatments with fenuron pellets, monuron powder, fenuron-trichloroacetate (TCA) granules, and monuron-TCA granules have consistently given plant kills in excess of 90 percent. Trichlorobenzoic acid granules have been less effective. An effective rate is an individual plant treatment of 2 grams active ingredient of fenuron pellets, monuron powder, fenuron-TCA granules, or monuron-TCA granules. The materials should be scattered around the base of the plant. Since these materials are desensitized by light and high temperatures, it is important that they be applied just before or early in an expected rainy season. This method is economical in controlling sparse stands of tarbush. It would be especially beneficial in areas where tarbush is invading grassland. The work reported was done on a silt loam soil in southern New Mexico.}, keywords = {description, Flourensia cernua, government publication, plant treatment, tarbush}, url = {/files/bibliography/097.pdf}, author = {C.H. Herbel} } @article {52476, title = {Vegetational changes on a semidesert grassland range from 1858 to 1963}, journal = {Ecological Monographs}, volume = {35}, number = {2}, year = {1965}, month = {1965}, pages = {139-164}, abstract = {

Extensive areas of the semidesert grassland of the Southwest are dominated by creosotebush [Larrea tridentata (DC) Coville], mesquite [Prosopis julifiora (Swartz) DC], and tarbush (Flourensia cernua DC). Mesquite occurs on 93,000,000 acres; creosotebush is present on 46,500,000; and tarbush occurs on 13,250,000 acres (Platt, 1959). Although the species are indigenous, they have invaded large areas in the past 100 years. Some areas invaded by tarbush still have a good understory of grass. However, loss of forage production occurs in early stages of mesquite invasion (Norris, 1950). In creosotebush-dominated areas, forage production is negligible (Gardner, 1951). The productivity of the rangeland greatly influences the economy of the Southwest. Therefore, it is important for the rancher to conserve and, where necessary, improve the range resource. Some knowledge of original vegetation conditions is essential in properly evaluating the potential of various sites. Much has been written about the semidesert grassland, including quotations from many early travelers. Some authors have based general assumptions on these quotations. However, the quotations are difficult to evaluate properly. In making their observations, many early travelers were influenced by the seasons and by their personal emotions. Furthermore, very few of the areas described by early travelers can actually be relocated for present-day comparisons. This study aims to show the degree of encroachment of brush on the study area and also the nature of the invasion on various soil types. Vegetation surveys of 1858, 1915, 1928, and 1963 were compared. Factors possibly responsible for the changes in vegetation were examined. This study was conducted on the Jornada Experimental Range, which is 23 mi north of Las Cruces, New Mexico.

}, keywords = {brush invasion, creosotebush, mesquite, monograph, semidesert grassland, tarbush, vegetation change}, doi = {10.2307/1948415}, url = {/files/bibliography/091.pdf}, author = {L.C. Buffington and C.H. Herbel} }