Journal of Range Management最新文献

{"title":"Germination of seeds of robust needlegrass.","authors":"James A. Young, C. Clements, T. Jones","doi":"10.2307/4003813","DOIUrl":"https://doi.org/10.2307/4003813","url":null,"abstract":"Robust needlegrass (Achnatherum robustum [Vasey] Barkw.) is a native perennial that has great promise for use in erosion control, restoration, and ornamental plantings. Seed dormancy can be a problem in developing new native grass cultivars, especially in species of Achnatherum and related genera. Germination response to a wide range of constant and alternating incubation temperatures is also a key parameter in interpreting seedbed ecology of potential planting material. Our purpose was to investigate the germination of robust needlegrass at 55 constant or alternating incubation temperatures from 0 through 40 C. Seeds of robust needlegrass germinate over a wide range of incubation temperatures with maximum observed germination over 75%. In terms of restoration ecology, this means that in contrast to many related grass species, severe seed dormancy is not a limiting factor in seeding technology. Optimum germination occurred with 15 to 20 C warm periods alternating with 0 to 20 C cool periods. The only constant temperature to produce optimum germination was 20 C. The highest germination occurred at what we consider moderate seedbed temperatures, but some germination occurred at 76 to 89% of the temperature regimes tested. DOI:10.2458/azu_jrm_v56i3_young","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80369051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resilience and the Behavior of Large-Scale Systems","authors":"A. Batabyal, L. Gunderson, Lowell Pritchard join","doi":"10.2307/4003824","DOIUrl":"https://doi.org/10.2307/4003824","url":null,"abstract":"","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85154540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adesmia subterranea Clos Germination Physiology and Presowing Treatments","authors":"C. Parera, M. Ruiz","doi":"10.2458/AZU_JRM_V56I3_PARERA","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I3_PARERA","url":null,"abstract":"The genus Adesmia (Fabaceae, Papilionoideae) is one of the scarce forage resources at high altitude and arid zones of South America. Its germination behavior has not been examined. Seeds of Adesmia subterranea \"Cuerno de Cabra\" were pretreated with sulfuric acid (1, 3, and 5 minutes soaking) and mechanical scarification to determine their impact upon dormancy and percentage and speed of germination. Treatments were evaluated under a range of constant temperatures (5 to 30 C) and 2 day/night cycles resembling the extreme environmental conditions of this species habitat. Water uptake and leachate conductivity were higher in the seeds scarified mechanically or with 5 minutes chemical scarification. These treatments also had the greatest total germination and rate at all temperatures in a petri dish germination test. However, in a cell tray experiment using a commercial substrate, the highest seedling emergence and rate were observed with chemical scarification (5 and 3 minutes). The high amount of leakage caused by the scarifications affected emergence in a non-sterile media. The results indicate that A. subterranea seeds have an impermeable seed coat which restricts water uptake, and the efficiency of sulfuric acid scarification to overcome seed coat impermeability and improve germination and emergence. DOI:10.2458/azu_jrm_v56i3_parera","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89009593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Economic and environmental impacts of pasture nutrient management","authors":"E. Osei, P. Gassman, L. Hauck, S. Neitsch, R. Jones, Jan Mcnitt, Heather E. Jones","doi":"10.2458/AZU_JRM_V56I3_OSEI","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I3_OSEI","url":null,"abstract":"Highly intensive stocking of dairy cattle on continuously grazed pasture coupled with liberal applications of commercial fertilizer can lead to increased losses of agricultural nutrients, which is a concern for water quality of receiving lakes and surface water resources. Integrated economic-environmental model simulations performed for the Lake Fork Reservoir Watershed in northeast Texas indicate that appropriate pasture nutrient management including stocking density adjustments and more efficient commercial fertilizer use could lead to significant reductions in nutrient losses. Soluble and organic P losses were predicted to decline by 54 and 13% relative to baseline conditions when manure P was assumed totally plant available (Low P scenario). The soluble and organic P loss reductions declined to 33 and 7% when only inorganic P was assumed plant available (High P scenario). Simulation of an N-based manure management plan resulted in the smallest predicted soluble and organic P loss reductions of 18 and 3%. Nitrogen loss predictions ranged from a 7% decline to a 1% increase for the 3 scenarios as compared to the baseline. The High P and Low P scenarios resulted in estimated aggregate profit reductions of 6 and 18% relative to the baseline. These profit declines occurred because the dairies had to acquire additional pasture land to accommodate the expanded area required for the P-based scenarios. In contrast, the N-based stocking density and nutrient management scenario resulted in an aggregate profit increase of 3% across all dairies. Variations in economic impacts were also predicted across farm sizes. DOI:10.2458/azu_jrm_v56i3_osei","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87620344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biological and chemical response of a grassland soil to burning.","authors":"L. Picone, G. Quaglia, F. García, P. Laterra","doi":"10.2458/AZU_JRM_V56I3_PICONE","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I3_PICONE","url":null,"abstract":"Changes in soil nutrient pools and microbial activity due to fire are important for understanding the availability of nutrients to plants. The objective of this study was to evaluate the effect of fire: 1) on size and seasonal dynamics of labile pools of C and N in a short-term after burning; and II) on chemical properties and microbial diversity immediately after fire, in a grassland with Paspalum quadrifarium Lam. Microbial biomass C and N tended to be higher in the burned (433 mg C kg-1 and 37 mg N kg-1) than in the unburned treatment (386 mg C kg-1 and 26 mg N kg-1). Both microbial biomass, decreased at the beginning of the growing season and then recovered at the end of the season. Levels of mineralizable C and N were similar in both treatments; however they showed different patterns of seasonal transformations. At initiation of plant growth, concentration of mineralizable C decreased while amount of mineralizable N increased; but the opposite occurred at the end of the growing season. Increases in microbial biomass coincided with low levels of mineralizable N and high concentrations of mineralizable C, suggesting a higher immobilization at the end of the season. Immediately after burning, organic C and N decreased by 11 and 7%, respectively. Mineral N was almost double, available P increased by 10 mg kg-1; but exchangeable bases, bacterial and actinomycetes population, and urease activity were not affected by burning. Fire can induce immediate changes to the soil; however, long-term studies will be required to evaluate the duration of the effect of fire on soil biological processes and nutrient transformations. DOI:10.2458/azu_jrm_v56i3_picone","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81312252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toxicity and development of tolerance in cattle to timber milkvetch","authors":"W. Majak, L. Stroesser, Timothy J. Lysyk, J. Hall","doi":"10.2458/AZU_JRM_V56I3_MAJAK","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I3_MAJAK","url":null,"abstract":"Timber milkvetch (TMV, Astragalus miser Dougl. ex Hook var. serotinus) is widely distributed on rangelands in the southern interior of British Columbia, Canada. It synthesizes large quantities of miserotoxin, a glycoside that is toxic to cattle. Six grazing studies were conducted at Sixtyone Creek on the Cariboo Plateau during 1993 to 2000 to determine which class of livestock was most susceptible to TMV, to record clinical signs of poisoning under range conditions, and to determine the efficacy of protein supplements for the prevention of TMV poisoning. In vitro rates of TMV detoxification in rumen fluid were determined concurrently. Incidents of early, acute and chronic poisoning were documented using a total of 143 cows over the 6 year study. Older cows (more than 3-years old) and yearling heifers were less susceptible to TMV than lactating first-calf heifers, which showed acute signs of poisoning. A chronic syndrome was sometimes seen in second-calf heifers, especially during exertion. Heifers not previously exposed to TMV, such as those that were obtained from the prairie region of Alberta, were also more susceptible than cattle originating in B.C. with a known history of exposure to TMV. Each year, Hereford cows were divided into 2 groups, one of which received free-choice protein supplements in a molasses block, the other did not receive supplement and served as a control group during the 6-week grazing trial. The control group yielded 25 cases of TMV poisoning during the 6-year study, compared with 2 for the supplement group. However, the supplement increased rates of TMV detoxification (> 50%) in only 1 of the 5 years of testing. Native cattle yielded higher rates of TMV detoxification (> 25%) in 2 of the 5 years than introduced cattle. The innate capacity to transfer rumen microbial activity between cattle in close proximity and the natural enrichment of rumen microbial populations could elevate rates of detoxification regardless of supplement or origin. DOI:10.2458/azu_jrm_v56i3_majak","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76865393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Survival of 16 alfalfa populations space planted into a grassland.","authors":"J. Hendrickson, J. Berdahl","doi":"10.2307/4003816","DOIUrl":"https://doi.org/10.2307/4003816","url":null,"abstract":"Many alfalfa (Medicago spp.) cultivars have limited ability to persist under grazing and therefore, a key step in incorporating alfalfa into pastures and rangelands is choosing a grazing tolerant cultivar. In this study, we evaluated the grazing tolerance of 16 alfalfa populations representing a range of potential grazing tolerance. Entries were transplanted on a rangeland site in July 1996 at the Northern Great Plains Research Lab in Mandan, N.D., USA and mob-grazed by cattle from 1997 to 2000. Plant survival, basal area, and stem numbers were recorded in the spring and fall of each year. At the final survival evaluation in May 2001, SCMF 3713 had the highest survival (90%), 'Vernal' had the lowest (23%) and 10 of the 16 entries had greater than 50% survival. A large decline in survival between September 2000 and May 2001 may be attributed to low temperatures in November and December of 2000. Entries such as 'Alfagraze', B-36 and Agripro ZG9415, which were developed in warmer climates, had the largest percentage drop in survival (43.0, 48.6, and 48.6 percentage points respectively) while SCMF 3713, 'Anik' and Alaska Syn A, developed in colder climates, had the least percentage point drops (2.8, 4.1, and 4.1 respectively). The ability to survive over winter contributed more to the different survival rates of these alfalfa populations than did any of the measured plant variables. Producers should know the origins of grazing tolerant alfalfa cultivars and consider selecting cultivars that have been tested in their area.","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76410901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fall grazing affects big game forage on rough fescue grasslands.","authors":"J. Short, J. E. Knight","doi":"10.2458/AZU_JRM_V56I3_SHORT","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I3_SHORT","url":null,"abstract":"Prescribed cattle grazing is often used to purposely enhance wildlife habitat. This study investigated the effects of fall cattle (Bos taurus) grazing intensity on elk (Cervus elaphus) and deer (Odocoileus spp.) forage in the following spring and summer. These effects were examined on rough fescue (Festuca scabrella Torr.) range on the Blackfoot Clearwater Wildlife Management Area in west central Montana. Cattle were grazed in enclosures during the fall of 1997 and 1998. A randomized complete block design with 5 replications of enclosures per year was used. Grazing levels were 0% removal (control), 50% removal, 70% removal, and 90% removal of herbaceous standing crop. To evaluate elk and deer forage, measurements were obtained in spring and summer on green grass standing crop, green forb standing crop, percent green vegetation, species richness, and plant species composition. There were no differences among grazing levels for plant species composition based on canopy coverage, species richness, and green forb standing crop variables ( P > 0.10). The 50% and 90% treatments reduced green standing crop in spring (P = 0.07) but not in summer (P > 0.10). Grazing treatments increased percent green vegetation (P < 0.01). Fall cattle grazing can be used as a wildlife habitat improvement tool to reduce unpalatable standing dead material. The 70% removal treatment was the most favorable for habitat improvement without degrading the range. DOI:10.2458/azu_jrm_v56i3_short","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77179708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Germination of seeds of big and bottlebrush squirreltail","authors":"James A. Young, C. Clements, T. Jones","doi":"10.2307/4003819","DOIUrl":"https://doi.org/10.2307/4003819","url":null,"abstract":"Bottlebrush squirreltail [Elymus elymoides (Raf.) Swezey] and big squirreltail [E. multisetus (J. G. Smith) Burtt Davy] are short-lived perennial bunchgrasses found on rangelands from the Pacific Coast to the Great Plains and from Canada to Mexico. They are highly variable species with several subspecies described for bottlebrush squirreltail. In many rangeland communities, bottlebrush squirreltail is the transitional dominant native grass in secondary successional communities. There is considerable interest in using squirreltail species in rangeland restoration seedings, but problems with seed collection (disarticulating rachis) have kept seed prices very high. Recently, grass geneticists have begun to develop lines of squirreltail for release as pre-varietal germplasm. Our purpose was to compare the germination at a wide range of constant or alternating temperatures of squirreltail seeds from developmental lines and material collected from native stands. Big and bottlebrush squirreltail seeds (caryopses) germinated over a wide range of temperatures. Seeds of bottlebrush squirreltail produced from the same stand in 3 different years had remarkably similar germination temperature profiles. The greatest variation in germination among accessions occurred at very cold and cold categories of seedbed temperatures. These differences may be very significant in the establishment of seedlings in the field. There was no one temperature regime that always supported optimum germination for all of the squirreltail accessions tested. The regimes most frequently supporting optimum germination were 15/20 and 15/25 C. The seeds of big and bottlebrush squirreltail tested do not have the ecological amplitude of seeds of the competitive exotic weed cheatgrass (Bromus tectorum L.), but they come close. DOI:10.2458/azu_jrm_v56i3_young2","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79289083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and use of state-and-transition models for rangelands.","authors":"B. Bestelmeyer, Joel R. Brown, K. Havstad, R. Alexander, G. Chavez, J. Herrick","doi":"10.2458/AZU_JRM_V56I2_BESTELMEYER","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I2_BESTELMEYER","url":null,"abstract":"State-and-transition models have received a great deal of attention since the introduction of the concept to range management in 1989. Nonetheless, only recently have sets of state-and-transition models been produced thatcan be used by agency personnel and private citizens, and there is little guidance available for developing and interpreting models. Based upon our experiences developing models for the state of New Mexico, we address the following questions: 1) how is information assembled to create site-specific models for entire regions, 2) what ecological issues should be considered in model development and classification, and 3) how should models be used? We review the general structure of state-and-transition models, emphasizing the distinction between changes among communities within states (pathways) that are reversible with changes in climate and \"facilitating practices\" (e.g. grazing management), and changes among states (transitions) that are reversible only with \"accelerating practices\" such as seeding, shrub control, or the recovery of soil stability and historical hydrologic function. Both pathways and transitions occur, so these models are complementary. Ecological sites and the climatically-defined regions within which they occur (land resource units) serve as a framework for developing and selecting models. We illustrate the importance of clearly delineating ecological sites to produce models and describe how we have dealt with poorly-delineated sites. Producing specific models requires an understanding of the multiple ecological mechanisms underlying transitions. We show how models can represent and distinguish alternative and complementary hypotheses for transitions. Although there may be several mechanisms underlying transitions, they tend to fall within discrete categories based upon a few, fundamental ecological processes and their relation-ships can be readily understood. A knowledge of mechanisms is closely related to the use of ecological indicators to anticipate transitions. We conclude that models should include 1) reference values for quantitative indicators, 2) lists of key indicators and descriptions of changes in them that suggest an approach to a transition, and 3) a rigorous documentation of the theory and assumptions (and their alternatives) underlying the structure of each model.","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84339849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}