Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 12/5/2005
Publication Date: 7/1/2006
Citation: Havstad, K.M., Fredrickson, E.L., Huenneke, L.F. 2006. Grazing livestock management in an arid ecosystem. In: Havstad, K.M., Huenneke, L.F., Schlesinger, W.H., editors. Structure and Function of a Chihuahuan Desert Ecosystem. The Jornada Basin Long-Term Ecological Research Site. Oxford, NY: Oxford University Press. p. 266-277. Interpretive Summary: In summarizing 45 years of grazing research in the arid region of south-central New Mexico, Paulsen and Ares (1961) wrote: “Sustained grazing capacity does not exist on the semi-desert ranges . . . stocking may be high in some periods (meaning that primary production is high and high livestock numbers would be appropriate) and in others there is virtually no capacity.” Our knowledge of various effects of livestock grazing in arid environments has been well synthesized (Pieper 1994). We have a general understanding of the importance of controlling timing, intensity, and frequency of grazing (Holechek et al. 1998b). It is also well recognized that livestock grazing under poor management or excessive use can have various negative effects, some of which are sever and long lasting. Proper utilization of forage species has long been recognized as a key component of livestock grazing management (Canfield 1939). Jardine and Forsling (1922) established early guidelines for carrying capacities of desert grasslands. These authors and others have repeatedly concluded that proper utilization of arid grasslands should be less than 40% of current year’s growth (Campbell and Crafts 1938; Paulsen and Ares 1962; Holechek et al. 1994; Holechek et al. 1999). The primary problems related to management of livestock grazing in arid and semiarid rangelands are those faced by producers since the seventeenth century: (1) coping with temporal variations in forage production, (2) manipulating an animal behavioral process (grazing) that is plant species specific, and (3) managing grazing across landscapes with limited (if any) ability to monitor or assess impacts. The most persistent problems are the annual and seasonal deficits in available forage due to the natural, recurrent disturbance of drought in this environment. Forage production on upland desert rangelands can average between 150 and 250 g/m2 (see Chapter 11, this volume) during years of normal precipitation but may be < 100 g/m2 during drought years (Herbel and Gibbens 1996; see Table 11-2, this volume). Almost any grazing during severe drought years would exceed proper utilization. Conservative stocking at 10-30% below capacity has also been recommended as both a strategy to cope with drought and as a means to improve vegetation conditions on some ranges (Holechek et al. 1999). Though Paulsen and Ares (1961) concluded that grazing could not be viewed as sustainable, to some extent this depends upon the spatial scale of livestock management. Conservative stocking is probably the most important practice to improve rangeland conditions and approach sustained livestock use of New Mexico’s arid rangelands. Based on our knowledge of the role of native consumers in this system, this recommendation reflects intent to minimize the affects of livestock on energy flows and appropriately manage their effects on ecosystem processes.
Technical Abstract: The history of livestock grazing in the Jornada Basin of southern New Mexico is a relatively recent story, but one of profound implications. For four centuries this region has supported a rangeland livestock industry, initially sheep, goats, and cattle, but primarily beef cattle for the past 130 years. Throughout this brief history of a domesticated ruminant in an ecosystem without a significant presence of large hoofed mammals as part of its evolutionary development, the livestock industry has continually grappled with high degrees of temporal and spatial variation in forage production. Management of this consumptive use, whether during Spanish, Mexican, United States Territorial, United States federal, or New Mexican governments, has constantly reaffirmed the need for grazing management to be flexible and responsive to the stress of droughts. The history of anecdotal experiences has been more recently augmented by scientific investigations first initiated in 1915. This chapter outlines the general history of livestock in this region, the historical specifics of ranching in the Jornada Basin, and resulting principles of grazing management derived from nearly a century of studies on grazing by large, domesticated herbivores.