Much of the North American prairielands have been converted into one of the richest agricultural regions on Earth. For the general public, grasslands do not exhibit the same need for protection as a rainforest or an old growth redwood stand BUT in truth grasslands are far more threatened. These ecosystems are critical for the health of our natural world.
The grasslands provide feeding grounds for all manner of prey and predators and give balance to the world. It is estimated that grazing land management and pasture improvement e. Milk and meat production from grassland systems in temperate regions has similar emissions of carbon dioxide per kilogram of product as mixed farming systems in temperate regions, and, if carbon sinks in grasslands are taken into account, grassland-based production systems can be as efficient as high-input systems from a greenhouse gas perspective.
Grasslands are important for global food supply, contributing to ruminant milk and meat production. Extra food will need to come from the world's existing agricultural land base including grasslands as the total area of agricultural land has remained static since Ruminants are efficient converters of grass into humanly edible energy and protein and grassland-based food production can produce food with a comparable carbon footprint as mixed systems.
Grasslands are a very important store of carbon, and they are continuing to sequester carbon with considerable potential to increase this further. Grassland adaptation to climate change will be variable, with possible increases or decreases in productivity and increases or decreases in soil carbon stores.
It divides the earth's terrestrial area into a number of classifications Table 1. For instance, most of Ireland is in this category. This paper reviews current thinking on grasslands in relation to food security and in relation to their associated greenhouse gas footprint, and also assesses both their vulnerability and adaptability to climate change.
There are also significant areas of grassland in Europe and North America that often are part of mixed cropland systems.
Excellent descriptions of the state of many of the great grasslands of the world by various authors have recently been compiled by FAO Suttie et al. Water is a hugely important factor in the use of land. Where water is sufficient, much of the world's natural grasslands have been converted to arable farming, and grazing only remains in these areas on the more marginal lands that are difficult or unfit for cropping.
Ramankutty et al. According to Buringh and Dudal , most of the world's grasslands five-sixths are on poor quality land with only one-sixth on land that was classified in the high and medium quality category. Suttie et al. Many of the problem arise from the breakdown of traditional tribal authority with centuries-old nomadic and transhumant grazing systems.
Population growth, urbanization, collectivization of farms and recent breaking up of collective farms, and land distribution have all contributed to a cessation of these traditional grazing systems in many regions, and their replacement with continuous overgrazing of the better grasslands and their subsequent deterioration.
In these conditions, the consequences of drought and soil erosion of grasslands are exacerbated. As discussed below, restoration of degraded lands including grasslands represents one of the largest greenhouse gas mitigation potentials in agriculture, but one which faces significant social, political and economic barriers to its achievement.
Most of this increase will come from countries in Asia, Latin America and Africa. The populations in the more-developed regions will remain more or less static between now and , and most of the increase will be in the least-developed countries and less-developed regions excluding the least-developed countries Fig. This will pose significant challenges to the food production system of the world.
World population projections source: United Nations, As well as population growth, the other driver of increased food demand is growing incomes.
This strong income growth will be reflected in particularly strong food demand as consumers in countries with low but increasing incomes devote a greater share of additional income to diet. Areas where food demand is expected to be particularly strong are eastern Europe, Asia and Latin America, less strong in sub-Saharan Africa, and stagnant in developed countries. In addition, as incomes rise, it is expected that there will be a shift towards more processed and prepared foods with a higher proportion of animal protein.
These differences are related to the projected evolution of the relative prices of different meats. As these trends are likely to continue past , a large increase in demand for food and food potentially produced on global grasslands can be anticipated. In addition, the trends shown in Table 2 of higher growth in consumption of animal products compared with cereals indicates that the growth in consumption of livestock products could be even higher.
The increase in food demand has contributed to land degradation, primarily through overgrazing, as outlined above. This is a complex issue and is related not just to the growing population, but also to political e. However, this increase occurred over the period — and since then, the total area has been static.
There is ongoing urbanization of agricultural land, so new land must be brought into production just to maintain the existing area of agricultural land. Increasingly, the land brought into agricultural use is in less-developed areas and in marginal regions with lower fertility and where there is a higher risk of adverse weather events than in more established agricultural production regions. Therefore the extra food required will predominantly have to come from the existing land base.
Thus there is a need to improve productivity from the existing land base since the conversion of additional poorer quality land to agricultural uses will otherwise lead to an overall decline in agricultural land productivity. The food products from grassland are milk and meat from ruminant animals. Ruminant animals can be fed on high-grain diets, but usually their diet involves some grazed or conserved grass or other fodder crop. For example, in Ireland, milk production is based predominantly on grazed grass, with some grain feeding and grass conserved as silage as the main winter feed O'Mara, In Ireland, beef cattle are fed predominantly on grazed grass with grass silage and some concentrate fed during the winter period, and sometimes high levels of concentrates in the finishing period O'Mara, In the United States and Australia, beef cattle are usually reared on pasture and finished on high-grain diets in feedlots.
Therefore, while grass is seldom the sole food in ruminant production systems, particularly in developed countries, it usually constitutes a major component of the diet. Milk and meat from ruminants are significant feedstuffs in the global food supply. Europe is the world region with the greatest bovine milk production Table 4 , but when total milk production is examined, the production of buffalo milk in Asia puts this region ahead of Europe, which is followed by North and Latin America.
This milk production, which is mainly from cows, is a more important source of nutrition than ruminant meat. In food energy terms, milk contributes two-thirds as much food energy as total meat production, and twice as much energy as from ruminant meat O'Mara, , thus underlying the very significant contribution it makes to global food supply. This is due to the higher animal productivity in these regions. Global production of meat tonnes from different species by world region in Global production of whole fresh milk tonnes from different species by region in There is concern about the use of grains in animal production that could be used to produce food eaten by humans.
However, much of the feed supply for ruminants worldwide comes from forages and low-quality arable crop by-products that are not suitable for use in human nutrition and that are very often grown in areas unsuited to arable agriculture. In addition, animal proteins generally have a greater biological value than vegetable proteins, and thus provide a further gain not measured by gross efficiency calculations.
In addition, grasslands provide important services and roles including as water catchments, biodiversity reserves, for cultural and recreational needs, and potentially a carbon sink to alleviate greenhouse gas emissions. Inevitably, such functions may conflict with management for production of livestock products. Much of the increasing global demand for meat and milk, particularly from developing countries, will have to be supplied from grassland ecosystems, and this will provide difficult challenges.
Dixon, Lauren L. Species diversity and dispersal traits alter biodiversity spillover in reconstructed grasslands. ScienceDaily, 28 August University of Missouri-Columbia. Grassland biodiversity is blowing in the wind. Retrieved November 12, from www. They found that ScienceDaily shares links with sites in the TrendMD network and earns revenue from third-party advertisers, where indicated. Print Email Share.
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