1.1 Description of LGT Production System
1.1.1 Geographic Distribution
Livestock grazing systems in true temperate zones (LGT) are most prevalent in Asia, with China and Mongolia having 60 percent of the agricultural land and 74 percent of the population in the LGT. There are also significant amounts of LGT pasture land in southern Argentina, northwestern United States, Canada, Turkey, and southeastern Australia (Table II.1). This AZ-LS category also represents significant portions of the total pasture land in several smaller countries, e.g., New Zealand and Chile. Agricultural lands are predominately pasture (only 7 percent arable) and relatively sparsely populated with 3.9 ha/capita overall. However, there is a great deal of variation in population density among countries such as China, Iran, Turkey, and Chile, which have densities of less than 2 ha/capita.
1.1.2 Livestock Resources
Although the LGT represents 13 percent of the world's pasture land, it only accounts for 2.5 percent of the cattle and 9.3 percent of the sheep and goats (Table II.2). Most (73 percent) of the cattle in the LGT are in the United States, Argentina, and China, while most of the sheep and goats (64 percent) are in New Zealand and China. Using livestock unit conversion factors designated by Sere to estimate LGT feed demand by the three types of livestock results in 54 percent being contributed by cattle. The only LGT countries where feed demand from sheep and goats exceeds that of cattle are New Zealand, Greece, Spain, China, and Iran.
1.1.3 Feed Resources
Grazed forage from native pastures is the predominate source of livestock feed in the LGT. Most of the improved, intensively managed pasture is in New Zealand. Supplementary feeding during winter, primarily with hay, is a common practice in much of the U.S. and Canada and is becoming more common in China. Significant weight loss during winter remains a significant factor in animal production efficiency in most of the LGT.
1.1.4 to 1.1.7 (See Sere 1994)
Table II.1. Human Population and Hectares of Arable and Pasture Land in the Livestock Grazing-Temperate Zone (excluding Africa and Tropical Highlands)
|
|
Human Pop. (mill) |
% of National Total |
Pasture Land (mill ha) |
% of National Total |
Crop Land (mill ha) |
% of Natl. Total |
||
|
OECD |
||||||||
|
|
North America: |
|||||||
|
|
Canada |
1.5 |
5.6 |
9.0 |
32.1 |
4.0 |
8.7 |
|
|
Iceland |
0.3 |
100 |
2.3 |
100 |
0 |
0 |
||
|
United States |
3.2 |
1.3 |
69.1 |
28.9 |
3.4 |
1.8 |
||
|
South Pacific: |
||||||||
|
|
Australia |
1.0 |
5.9 |
13.0 |
3.1 |
2.5 |
5.3 |
|
|
New Zealand |
0.2 |
5.9 |
7.0 |
51.1 |
0 |
0 |
||
|
Europe: |
||||||||
|
|
Greece |
0.2 |
2.0 |
1.7 |
32.1 |
0.1 |
2.6 |
|
|
Ireland |
0.3 |
2.9 |
2.3 |
12.8 |
0.1 |
11.1 |
||
|
Portugal |
0.6 |
6.1 |
0.3 |
37.5 |
0.9 |
28.1 |
||
|
Spain |
1.5 |
3.8 |
4.0 |
38.8 |
2.1 |
10.4 |
||
|
Switzerland |
0.7 |
46.2 |
1.0 |
62.5 |
0.1 |
25.0 |
||
|
United Kingdom |
0.4 |
0.7 |
1.2 |
10.7 |
0.6 |
9.1 |
||
|
CSA |
||||||||
|
|
Argentina |
7.8 |
24.1 |
42.7 |
30.0 |
1.8 |
7.2 |
|
|
Chile |
4.5 |
34.1 |
4.8 |
35.6 |
1.4 |
3.5 |
||
|
ASIA |
||||||||
|
|
China |
87.3 |
7.8 |
172.0 |
43.0 |
15.0 |
15.5 |
|
|
Mongolia |
1.7 |
77.3 |
96.5 |
77.4 |
0 |
0 |
||
|
WANA |
||||||||
|
|
Iran |
1.2 |
2.1 |
1.6 |
3.6 |
0.3 |
2.0 |
|
|
Turkey |
8.4 |
15.0 |
12.8 |
25.8 |
1.0 |
4.0 |
||
|
TOTAL |
120.8 |
|
441.3 |
|
33.3 |
|
||
|
% of World LGT |
64 |
|
86 |
|
83 |
|
||
|
% of World Total |
2.2 |
|
13.2 |
|
2.5 |
|
||
|
|
Cattle (mill) |
% of Natl. Total |
Sheep (mill) |
% of Natl. Total |
Goats (mill) |
% of Natl. Total |
||
|
OECD |
||||||||
|
|
North America: |
|||||||
|
|
Canada |
2.5 |
22.3 |
0.4 |
50.0 |
0 |
0 |
|
|
Iceland |
0.1 |
100 |
0.7 |
100 |
0 |
0 |
||
|
United States |
6.0 |
6.9 |
0.5 |
4.4 |
0.1 |
5.3 |
||
|
South Pacific: |
||||||||
|
|
Australia |
1.1 |
4.7 |
3.0 |
1.8 |
0.1 |
16.7 |
|
|
New Zealand |
1.8 |
22.2 |
36.0 |
62.2 |
0.8 |
72.7 |
||
|
Europe: |
||||||||
|
|
Greece |
0.1 |
16.7 |
3.7 |
42.5 |
2.3 |
43.4 |
|
|
Ireland |
1.0 |
16.9 |
1.0 |
17.2 |
0 |
0 |
||
|
Portugal |
0.4 |
30.8 |
2.0 |
35.7 |
0.3 |
33.3 |
||
|
Spain |
1.0 |
19.6 |
8.0 |
33.3 |
2.0 |
54.1 |
||
|
Switzerland |
1.0 |
52.6 |
0.3 |
75 |
0.1 |
100 |
||
|
United Kingdom |
1.1 |
10.1 |
3.0 |
10.1 |
0 |
0 |
||
|
CSA |
||||||||
|
|
Argentina |
10.7 |
21.1 |
7.0 |
24.5 |
1.8 |
54.5 |
|
|
Chile |
1.0 |
30.3 |
2.3 |
34.8 |
0.3 |
50.0 |
||
|
ASIA |
||||||||
|
|
China |
6.7 |
8.7 |
24.8 |
21.9 |
40.7 |
41.4 |
|
|
Mongolia |
1.8 |
66.7 |
9.3 |
65.0 |
3.5 |
70.0 |
||
|
WANA |
||||||||
|
|
Iran |
0.1 |
1.3 |
0.6 |
1.3 |
0.3 |
1.2 |
|
|
Turkey |
1.0 |
8.2 |
3.9 |
8.9 |
1.7 |
14.3 |
||
|
TOTAL |
32.0 |
|
106.5 |
|
53.0 |
|
||
|
% of World LGT |
46.4 |
|
86.4* |
|
86.4* |
|
||
|
% of World Total |
2.5 |
|
9.3* |
|
9.3* |
|
||
|
* Sheep plus goats |
|
|
|
|
|
|
||
1.2.1 Livestock Resources
Overall, cattle numbers have shown only a slight increase in the LGT during the past decade. Significant growth in numbers has occurred only in China and Mongolia. Stocks of sheep have declined significantly over the past decade, mostly due to large reductions in New Zealand and the United States. Alternatively, goat populations have increased modestly overall with significant increases in China, where an increased emphasis was placed on cashmere production.
1.2.2 Production Technology, Livestock Use, and Products
Dairy cattle stocks and milk production have increased modestly over the LGT during the past decade, as have poultry meat, and egg production. Production of pork has increased only slightly overall but has grown in China by almost 10 percent (from a very small base).
Grazing animal production technology continues to increase production efficiency both per animal and per unit area. Increases in efficiency continue to result from ongoing development and adaptation of better breeding stock, better understanding of nutritional relationships and procedures for supplemental feeding, and better systems for maintaining animal health. In many less developed countries, the growth of transportation and communications infrastructures has made marketing of animals and animal products outside of their remote production regions more plausible.
1.2.3 Trends toward Alternative Production Systems
Within the LGT in China there has been a significant trend toward a mixed rainfed system where climatic conditions allow. Unfortunately, this trend resulted in significant amounts of formerly productive, sustainable grassland being exposed to severe erosion. Some of these areas that were cropped are once again being used as pasture, but they are now far less stable and productive than before they were cropped.
1.3. Overview of Key Indicators
1.3.1 Direct Indicators
1.3.1.1 Soil Erosion
Livestock grazing impacts the rangeland watershed through removal of protective cover and through trampling disturbance. Effects may include altered water quality, increased overland flow, reduced soil moisture, and increased erosion. Consequently, improper livestock grazing management effects may be manifested as a nonpoint source of pollution and may ultimately result in loss of productivity from rangelands. In their summary of a literature review on the influence of grazing on watershed parameters, Blackburn et al. (1982) stated that most studies reported little or no difference in sediment production from light and moderately grazed pastures. Likewise, many studies reported no difference between nongrazed areas and light or moderately grazed pastures. However, heavy continuously grazed pastures almost always show an increase in sediment production over light, moderate, or nongrazed pastures.
Where there is root stock or a seed source remaining, the obvious key to reduction of soil loss through erosion is altering the use of soil cover by grazing animals. In most cases, this approach does not mean that no grazing takes place, but rather that controlled grazing allows adequate levels of biomass to remain on and above the soil surface. Grazing management, including the possibility of grazing systems, to provide rest periods and proper levels of plant defoliation should be promoted.
1.3.1.2 Water Quality
In Livestock Grazing Temperate (LGT) regions, riparian and meadow communities are considered critical resource areas for livestock and wildlife. Availability of water for drinking and producing high quality forage is often a major constraint to livestock production throughout most LGT regions, and its presence or absence generally has a major influence on livestock use of associated upland ecosystems in the watershed. Consequently, water and associated riparian and meadow communities often are a focal point for livestock and wildlife use.
Depending on the season in LGT regions, riparian and meadow areas have more succulent forage, shade, reliable water supply, accessibility, and favorable microenvironment compared to associated upland range. These characteristics tend to attract and hold livestock unless livestock management strategies are designed and implemented that will distribute animals to upland foraging areas.
Livestock grazing and trampling can negatively affect riparian and meadow communities and the stream itself by reducing or eliminating riparian vegetation, changing stream bank and channel morphology, and increasing sediment load in streams. Also viewed negatively is the potential increase in coliform bacteria associated with livestock fecal deposition in or near the stream. Nutrient loss can occur in overgrazed and trampled riparian and meadow areas, but the loss is minimal where the streamside vegetation remains in good condition. Streamside vegetation has the capacity to buffer the stream from direct waste input and assimilate the nutrients into plant tissue.
Although it is well documented that livestock and wildlife will seek out and use riparian and meadow communities and that this use can adversely impact quality and stability of these critical resource areas, many different factors will actually determine the impact of livestock on the riparian zone. These factors include a) management constraints that confine livestock to riparian and meadow areas, b) type and availability of water sources, c) factors associated with terrain that predispose the grazing animal to increase the amount of time in areas near water sources, and d) season of the year which influences the animal's need for water or influences animal behavior relative to grazing and the need for water. A sufficient number of disparate variables are involved in livestock grazing in general and for riparian and meadow communities that precludes making generic assumption that any and all livestock grazing will be detrimental to these critical resources. Each water source needs to be evaluated in terms of problems associated with livestock use.
1.3.1.3 Botanical Composition, Upper and Lower Layers
The literature contains extensive references to changes in vegetation composition caused by the influence of livestock grazing in grassland and forest ecosystems. The most common manifestation of vegetation change is the result of livestock overutilization of the herbaceous component. Those species that are preferred first and foremost by livestock are subjected to inordinate grazing pressure and physiological stress. Such species usually decline in relative composition in stands compared to less preferred, less abusively grazed species. Therefore, within the ground-based layer of vegetation, a shift from most palatable to less palatable vegetation, as a result of preference of grazing animals, is common. This preference explains the shift over time from tall, broadleaf, palatable grass species preferred by cattle to midgrasses and even shortgrasses as overgrazing continues. Likewise, however, with goats as the grazing animals, highly preferred browse plants may be progressively reduced in relative composition compared to herbaceous species. It is important to differentiate the act of grazing, an evolutionary component of grassland ecosystems, with overgrazing or overutilization of the range.
With shifts in the ground layer of range vegetation as the result of overgrazing, soil cover and protection from the deleterious effects of high intensity precipitation events and high wind velocities are diminished. This change increases the opportunity for soil movement by wind and water and can result in unrecoverable erosion losses.
As the ground layer of vegetation is reduced in competitive capability with shrubs and tree-type vegetation, these plants find a niche in grassland ecosystems and often become dominant. Domestic livestock have apparently improved the dispersal of seed for several woody species and have also enhanced the chance of germination and survival in a grassland environment. These woody plants may have been part of the natural potential vegetation, but increase in density and distribution in a disturbance regime that reduces the herbaceous layer. Once established, woody plants form an overstory that in turn intercepts sunlight and competes vigorously with the herbaceous layer for soil moisture and nutrients. Woody plants are able in many cases to escape grazing stress by growing above the browsing height of animals. Concomitantly, as the herbaceous layer is further diminished, the role of fire to suppress woody plants diminishes due to inadequate fuel loads and fuel continuity to cause significant damage to woody overstory. As the canopy cover of woody plants increases and approaches closure, there is an incremental decrease in the herbaceous component of vegetation. This, in turn, ensures that there is insufficient fuel load and distribution to significantly damage woody plants with fire, a cycle that gets progressively worse as woody plants increase.
Several researchers who have elucidated the role of increasing atmospheric CO2 on vegetation feel that plants with a C3 carbon pathway will have a comparative advantage as CO2 levels continue to rise. Thus, significant shifts in range vegetation may occur, which in turn will influence total forage production, kind of forage/browse production, and most appropriate grazing animal.
Thomas (1994) states that a major objective of U.S.-supported development assistance in the past forty years was to improve the standard of living for all people in the developing world. At the same time, most world watchers realize wealthy or middle-class people place more pressure on the environment than do poor people. Wealthy people require more units of land, more units of water, and more units of energy. Higher per capita incomes mean greater problems of pollution and contamination. Yet, states Thomas, we cannot be in the position of trying to keep people who are living at a subsistence level from using the sparse resources at hand to maintain their families. If people are going to care for the environment, it will be those who live there.
Concentration of the human population can also be a factor related to resource use. A classic example of the interjection of governmental policies into grazingland management can be found in the Asian steppes where the traditionally transhumant herders and their families have changed to a more sedentary life-style in villages. As population is concentrated, the stress on resources increases, often resulting in vegetation degradation, soil erosion, and irrecoverable productivity loss.
The role of domesticated grazing animals in contributing to the change in vegetation on rangelands has historically been negative, that is, resulting in less of the preferred forage species, as the grazing animals are, through necessity, changed from those primarily using perennial herbaceous species to annuals and finally to shrubs. Generally, the change is from ground layer dominance to dominance by overstory plants that can physically resist grazing by most domestic animals.
With livestock grazing, which is the most powerful human influence on rangeland other than housing development and conversion to cropland, considerable attention has been directed to minimizing its impact. Controlling the timing, duration, and intensity of grazing appears to be the key. Many perennial range grasses, particularly prairie grasses, are adapted to periodic, sometimes intense, grazing. Periods of rest allow grazed perennials to replenish leaf area, set seed, and store food reserves in their roots. Continuous or too frequent access to the same range by large numbers of livestock impedes the ability of new growth to store food. When perennial grasses are repeatedly cropped back, leaf growth takes precedence over root growth. With continued severe grazing, roots die and plants become less vigorous. The result is reduced forage and greater plant susceptibility to drought and disease. Watershed protection also suffers as plant cover and leaf litter diminish, leaving erodible, exposed soil (World Resources Institute 1994).
In general, North American range conditions reflect a pattern of early overuse by cattlemen and sheep herders, followed by slow recovery as ranching and public land management practices improved. According to some reports, U.S. rangelands are in better shape today than at any time in this century, even though they are still degraded compared to their natural potential vegetation. A report by the U.S. General Accounting Office stated that in 1988 available trend information indicated that although most public rangelands were either stable or improving, one out of five BLM and Forest Service allotments may be threatned with further damage because more livestock were being permitted to graze than range managers believed the land could support (U.S. General Accounting Office 1988). The fact that there has been general improvement in range condition in the U.S. is strong evidence that the management principles used to effect this change merit consideration for other rangeland areas of the world.
1.3.1.4 Forest Utilization
Livestock grazing can have both positive and negative impacts on botanical composition of forested ecosystems, depending on the type of forest ecosystem and the type of livestock production system. Positive impacts associated with livestock production in silvo-pastoral systems in the tropics include biological advantages, i.e., both improving soil nutrients while supporting considerable livestock grazing. Grazing improved soil fertility, increased efficient use of solar energy, and facilitated nutrient recycling. The dual production system also had economic advantages.
In drier forest ecosystems, continuous overgrazing of understory and use of tree foliage as livestock fodder can lead to rapid degeneration of forest ecosystems. Negative impacts of forest grazing can also be associated directly with livestock production. In New Zealand pine forests, development of the tree canopy caused a decline in forage quality as indicated by reduced wool weight from sheep and reduced livestock growth rates.
In western North America, Douglas fir forest ecosystems, shrub species preferred by livestock and big game wildlife, occur mostly in open sites following logging. In the Pacific Northwest of the United States, sheep grazing effectively reduced understory plant growth and the net current year's growth of brush on tree plantations, while allowing improved growth of Douglas fir saplings. Clearing and thinning increases the amount and diversity of available forage for goats in caatinga vegetation of northeastern Brazil.
In general it would appear that grazing is not detrimental to tree growth in most forest types unless grazing is permitted to occur on young trees prior to reaching sufficient height to avoid being grazed or trampled. Livestock grazing, depending on the understory plant species and forest ecosystem, can change species composition of understory brush. As canopy cover of trees increases, grass and shrub production of understory forage will become a limiting factor for livestock and big game grazing.
1.3.1.5 Wildlife-Livestock Interactions
Livestock in extensively managed production systems typical of LGT regions usually interact to a degree with wildlife in competing for food or space. This interaction can have a positive, negative, or no impact. Currently in most LGT regions, an increasingly vocal segment of the general public perceives the interaction as being negative, especially relative to the impact of livestock grazing on threatened or endangered wildlife or plant species.
In riparian areas, livestock grazing is generally perceived as having a negative impact on fish and other aquatic species because grazing can alter stream hydrologic flows and reduce habitat diversity by altering or reducing stream bank vegetation. In the Pacific Northwest of the United States, livestock grazing of riperian zones associated with salmonid spawning and rearing areas is perceived as having a direct negative impact on recovery of salmonid populations.
In most LGT regions, multiherbivore grazing commonly occurs. Livestock and wild herbivores can compete directly or indirectly for food, cover, and water. Usually, the potential competition for food is perceived as being the most important interaction, especially between livestock and big game wildlife. Livestock can impact wildlife by utilizing key forage species needed by wild herbivores during critical times of the year, by altering short- and long-term habitat quality, and by transmitting disease.
Interactions between wildlife and livestock are not always negative. Properly managed livestock can be used as a tool to improve wildlife habitat. In the Intermountain Region of the western United States, judicious cattle grazing during the summer can improve quality of forage available to large wild herbivores using seasonal rangelands during other times of the year. Grazing management strategies developed to improve for the livestock production should also account for the needs of all wildlife.
1.3.1.6 Habitat Composition Changes/Biodivesity
In most LGT regions of the world, herbivory has occurred for millennia. However, not all LGT regions were subject to the concentrated herbivory of domestic livestock that differed significantly from native herbivores in intensity, season, and dispersal across the landscape. The introduction of domestic livestock to LGT regions of North America and the attempt to intensify livestock production in LGT regions of Mongolia and Inner Mongolia have altered habitat for wildlife. Often the intensification of livestock production has been accompanied by the direct human conversion of native vegetation communities to communities more suited to maximize livestock production.
The act of grazing by domestic livestock can in itself, either through direct and indirect impact on vegetation or through impacts associated with trampling, alter habitat. In areas of concentrated livestock use, such as riparian areas, the potential for altered habitat is high. The greatest impact of domestic livestock on wildlife is through alteration of habitat that changes plant species composition and/or community structure.
An increase in livestock management awareness is critical in LGT regions having several herbivores using the same habitat. For example, using animal unit equivalents to allocate forage between domestic and wild herbivores does not usually reflect actual forage and habitat needs of the wild herbivores. Management of livestock use in riparian and meadow communities is especially critical because of the high probability that habitat for nonherbivores will be drastically altered if livestock are allowed to follow their natural propensity to concentrate use.
