DALRYMPLE AND DWYER 145 rate. As the planting date neared LITERATURE CITED WEAVER,J. E. 1947. Rate of decom- position of roots and rhizomes of spring, grasses began to grow HIRONAKA, M. 1961. The relative certain range grasses in undis- rate of root development of cheat- more normally. Sideoats grama turbed prairie soil. Ecology 28: - grass and medusahead. J. Range was the only species that pro- 221-240. Manage. 14: 263-267. duced a normal appearing in- LARIN, I. V. 1962. Pasture rotation. WEAVER, J. E. 1954. North Ameri- Johnson Publ. Co. florescence. Office of Technical Services. U.S. can prairie. Lincoln, Neb. p. 86-102. Sideoats grama was first in Dept. of Commerce. Washington, development of seedling emer- D.C. 204 p. WEAVER,J. E., AND F. W. ALBERTSON. 1943. Resurvey at the end of a gence, various leaf and tiller NEWELL, L. D., R. D. STATEN, E. B. JACKSON, AND E. C. CONRAD. 1962. great drought. Ecol. Monog. 13: - stages and inflorescence forma- Sideoats grama in the Central 65-117. tion. These are important fea- Great Plains. Univ. of Neb. Res. WEAVER,J. E., AND ELLENZINK. 1945. tures of a grass used in reseed- Bull. 307. 38 p. Extent and longevity of the semi- ina. All grasses except little blue- SULLIVAN,J. T., AND V. G. SPRAGUE. nal roots of certain grasses. Plant A Physiol. 20: 359-379. stem showed good seedling vigor. 1949. The effect of temperature on the growth and composition of WEAVER,J. E., ANDELLEN ZINK. 1946. This could be because all species the stubble and roots of perennial Annual increase of underground except little bluestem were im- ryegrass. Plant Physiol. 24: 706- materials in three range grasses. proved varieties. 719. Ecology 27: 115-127. 9 8 Plant Succession with Released Grazing pled. Through a cooperative agreement with the Rocky Moun- on New Mexico Range Lands’ tain Forest and Range Experi- ment Station arrangements were LOREN D. POTTER AND JOHN C. KRENETSKY made to reassess the plots after Chairman and Graduate Assistant, Department of Bi- approximately 25 years of graz- ology, University of New Mexico, Albuquerque. ing protection within the exclo- sures. The history of the inten- Highlight vegetational cover and composi- sity of grazing for each area is After 25 years of protection from tion cannot be attributed entire- incomplete, and certainly in- grazing, grassland plots tripled in ly to grazing, for no single fac- definite for the area immediate percent of ground cover of grasses. Grazed desert grasslands showed tor can be all-destructive or sing- to the plot. However, the rate of coniinued increases of mesquiie. Pro- ly effective. grazing has generally been under feciion resulfed in remarkable in- A farsighted research program creases in grass cover in ponderosa better control and has been pine and aspen types. within the U.S. Forest Service moderate, with one noted excep- recognized the need for estab- tion, since 1940. The increased emphasis of the lishing protected areas on gov- In spite of the several centuries importance of vegetational cov- ernmental forest and range lands of grazing in the Southwest there is er as it affects the watershed to evaluate vegetational recov- little specific knowledge of the vege- value of range and forest lands ery with removal of grazing of tation and its succession in New requires further ecological un- domestic livestock. Fenced range Mexico as indicated by the sparsity derstanding of plant succession. study plots, approximately one of publications; but pertinent ones include those of Gardner and Hub- Throughout the Southwest, with acre in size, were located in rep- bell (1943), Bostick (1947), Canfield a history of four centuries of resentative vegetational types (1948), and Norris (1950). General grazing by horses, cattle, sheep, throughout the National Forests. vegetational descriptions include and goats, the productivity and In the Southwest these included those of Watson (1912) and Castetter vegetational cover have been semi-desert shrub, desert grass- (1956). The desert plains grassland greatly modified with almost no land, blue grama plains, pinyon- has been discussed by Whitfield and areas left ungrazed to serve as a juniper, pondersoa pine, mixed Beutner (1938) and Gardner (1950). standard of the original climax conifer, and aspen-meadow. They Coactions of range animals and live- condition. The retrogressions of were located onvarying slope ex- stock on semidesert range land were reported by Norris (1950) and the posures and soil types. A method succession and grazing capacity of 1 Support from a cooperative agree- of comparative study inside and clay soils in New Mexico by Camp- ment with the Rocky Mountain For- outside of the livestock exclosures bell (1931). Gardner (1951) gave a est and Range Experiment Station, using permanently marked line Forest Service, U.S.D.A., for the complete discussion of creosote bush summers of 1963-64 is gratefully transects was initiated from 1939 plains. The pinyon-juniper woodland acknowledged. to 1943, and some plots were sam- of New Mexico was analyzed by 146 SUCCESSION, NEW MEXICO Woodin and Lindsey (1954). More However, the stratified method was state of New Mexico were local studies of pinyon-juniper in- used in selecting the position of each divided into six major vegetative clude those of Watson (1912) in transect within the plots. Ten 50-ft types: Grassland, Desert Grass- north-central New Mexico, Emerson long line transects were located in land, Sagebrush, Pinyon-Juniper, (1932) in the grama grass and pin- each 50 x 100 ft subplot to duplicate Ponderosa Pine, and Aspen. Be- yon-juniper tension zone of north- the original positions located by cause the plots of grassland type eastern New Mexico, Howell (1941) random numbers. These sample loca- in classifying the type in northern tions are permanently recorded.” were within National Forests, New Mexico, Dortignac (1956) in the The method used in the original which generally include wood- Upper Rio Grande Basin, and Potter analysis had to be repeated to make land and forest areas, the type is (1957) in a phytosociological study the data comparable. In using Can- represented by open grassland of the San Augustin Plains. Few field’s line interception method all sites, or meadows, within pin- studies of grazing succession in pon- species under the wire are listed and yon-juniper or ponderosa pine derosa pine and in spruce-fir are their total linear coverage, in hun- zones rather than extensive available for New Mexico. dredths of a foot, recorded as basal grasslands below the woodland diameter of grasses and herbs but A project for obtaining basic infor- zone. as live-crown cover of shrubs and mation on plant cover, forage pro- In exploratory studies relating ductivity, plant succession, water rosette-forming herbs. The basal to range conditions in the pin- relations, and soil development measurements allow even grazed seemed appropriate at a time when plants to be measured and are less yon-juniper zone of the Rio millions of dollars might be saved likely to be influenced by the stage Grande Basin in New Mexico, with additional knowledge of this of development or short-term en- H. W. Springfield3 analyzed the kind. The need for a thorough eco- vironmental conditions (Canfield, woodland study plots and found logical knowledge of watersheds has 1941). that at the time of establishment been stressed by Price (1958). Results and Discussion and initial sampling in 1939 or Reservoirs behind large dams built A total of 34 different range 1940 there was no real difference at ever larger costs are rapidly filling study plots from the Apache, in the grass density on the plots with silt. Ranchers reminisce about Carson, Cibola, Gila, Lincoln, and selected for protection and those rangelands of swaying grass instead Santa Fe National Forests were for continued grazing treatment. of dust and thistles, and technicians know too few of the answers about analyzed in 1963 and 1964. Un- GrassZa?zd Type. - Eight plots the “why” of the cause or the “how” fortunately, because of incom- are included in this type with of restoration. plete original data, destruction of elevational ranges from 5,200 to both inside and outside staked 9,400 ft. The ground cover of Methods plots, or loss of stakes in the grasses increased in both pro- To gain the quantitative data nec- grazed plots so that new tran- essary for this study, permanent, tected and grazed plots in the sects had to be established, only paired plots had been established by last 25 years. Generally, only a placing one inside and one outside of 26 of the 34 plots could be used few grass species of minor im- the exclosures. These plots are 100 in the comparative summary portance invaded either the pro- ft sq in all forests except Cibola, analysis. Additional plots for tected or grazed plots; thus, sam- where they are 50 x 100 ft. The plots which original transect data were ples of this type showed little were marked by permanent iron available were not sampled in benefit of protection through stakes at the time of installation in the field because the fences change in floristic composition. 1939-1943. In subjectively establish- around the exclosures had not The cover of forbs averages ing the plots an attempt (not always been maintained to prevent live- less than 1% and shows no real successful) had been made to place stock grazing, roads had been the pairs in similar physiographic increase or consistent trend in built across the plots, trees in and vegetational areas and to orient relation to grazing. their sides with respect to the four the plots had been bulldozed, or The average coverage of cardinal compass points. Each 100 ft lumbering in the grazed plot had browse decreased in both pro- sq plot was divided, and marked by artifically changed the commu- tected and grazed areas, due iron stakes, into two 50 x 100 ft nity and introduced a major principally to the outstanding subplots.