Reactions of northern California grass-woodland to vegetational type conversions

Heady, H; Pitt, M

Reactions of northern California grass-woodland to vegetational type conversions

Authors

H. F. Heady
M. D. Pitt

Authors Affiliations

H. F. Heady was Professor of Range Management, Department of Forestry and Resource Management; he is also Assistant Vice President of Agriculture and University Services, and Associate Director, Agricultural Experiment Station, Berkeley; M. D. Pitt was formerly Research Assistant, Department of Forestry and Resource Management, Berkeley, is Assistant Professor of Range Ecology, Department of Plant Science, University of British Columbia, Vancouver, B.C., Canada.

Publication Information

Hilgardia 47(3):51-73. DOI:10.3733/hilg.v47n03p051. April 1979.

PDF of full article, Cite this article

Abstract

Changes in standing crop, cover, and percent botanical composition of annual vegetation as influenced by microsite and type conversion were investigated on an 86.2 hectare watershed at the Hopland Field Station, Mendocino County, California.

Type conversion from woody vegetation to grassland tripled total standing crop of herbaceous plants on the watershed, with much of this increase occurring on sites formerly supporting a dense and semi-dense woodland overstory. However, the sites that were originally woodland never produced as much forage as those that were originally open grassland. The managerial problem of seasonally adjusting stocking rates in response to changing forage availability was heightened by type conversion, since much of the increased forage production occurred at the end of the growing season.

Short annual plants, such as nitgrass, silver hairgrass, rattlesnake weed, filaree, bur-clover, and true clovers, attained their greatest percent botanical composition on the historically open grassland sites. Type conversion produced increases in botanical composition primarily for those taller annual and perennial plant species capable of colonizing the formerly dense woodland sites mainly occurring on north-facing slopes. These plant species included wild oats, ripgut, vetches, and Italian thistle.

In the sheep-grazing system employed, adding animal units to utilize increased spring forage following brush conversion required alternative sources of feed during other periods of the year.

Literature Cited

Bentley J. R. Conversion of chaparral areas to grassland: Techniques used in California. U.S. Dept. Agric. Handb. 1967. #328:

Bentley J. R., Talbot M. W. Efficient use of annual plants on cattle ranges in the California foothills. U.S. Dept. Agric. Circ. 1951. 870:

Biswell H. H. Ecology of California grasslands. J. Range Manage. 1956. 9(1):19-24. DOI: 10.2307/3894645 [CrossRef]

Burgy R. H., Papazafiriou Z. G. Vegetative management and water yield relationships 1974. Proc. 3rd Int. Semin. Hydrol. Professors. Purdue Univ., July 18-30, 1971. pp. 315-31

Duncan D. A., Woodmansee R. G. Forecasting forage yield from precipitation in California’s annual rangeland. J. Range Manage. 1975. 28(4):327-29. DOI: 10.2307/3897788 [CrossRef]

Gowans K. D. Soil survey of the Hopland Field Station. Calif. Agric. Exp. Sta. 1958.

Heady H. F. Evaluation and measurement of the California annual type. J. Range Manage. 1956. 9(1):25-27. DOI: 10.2307/3894646 [CrossRef]

Heady H. F. Effect of cages on yield and composition in the California annual type. J. Range Manage. 1957. 10(4):175-77. DOI: 10.2307/3893815 [CrossRef]

Heady H. F. Vegetational changes in the California annual type. Ecology. 1958. 39(3):402-15. DOI: 10.2307/1931750 [CrossRef]

Heady H. F. Continuous vs. specialized grazing systems: A review and application to the California annual type. J. Range Manage. 1961. 14(4):182-93. DOI: 10.2307/3895147 [CrossRef]

Hooper J. F., Heady H. F. An economic analysis of optimum rates of grazing in the California annual-type grassland. J. Range Manage. 1970. 23(5):307-11. DOI: 10.2307/3896155 [CrossRef]

Hormay A. L. Moderate grazing pays on California annual-type ranges. U.S. Dept. Agric. Leaf. 1944. 239:

Jones M. B., Evans R. A. Botanical composition changes in annual grassland as affected by fertilization and grazing. Agron. J. 1960. 52(8):459-61. DOI: 10.2134/agronj1960.00021962005200080011x [CrossRef]

McNaughton S. J. Structure and function in California grasslands. Ecology. 1968. 49(5):962-72. DOI: 10.2307/1936547 [CrossRef]

Murphy A. H. Predicted forage yield based on fall precipitation in California annual grasslands. J. Range Manage. 1970. 23(5):363-65. DOI: 10.2307/3896168 [CrossRef]

Naveh Z. Mediterranean ecosystems and vegetation types in California and Israel. Ecology. 1967. 48(3):445-59. DOI: 10.2307/1932680 [CrossRef]

Pitt M. D. The effects of site, season, weather patterns, grazing, and brush conversion on annual vegetation, Watershed II, Hopland Field Station 1975. p.281. Univ. Calif. Ph.D. diss

Pitt M. D., Heady H. F. Response of annual vegetation to temperature and rainfall patterns in northern California. Ecology. 1978. 59(2):336-50. DOI: 10.2307/1936378 [CrossRef]

Talbot M. W., Biswell H. H. The forage crop and its management. Univ. Calif. Agric. Exp. Sta., Bull. 1942. 633:13-49.

Talbot M. W., Biswell H. H., Hormay A. L. Fluctuations in the annual vegetation of California. Ecology. 1939. 20(3):394-402. DOI: 10.2307/1930392 [CrossRef]