Usually the focus in conservation policy has been on their role for biodiversity, says Janne Bengtsson. If well managed, they can contribute to counteracting climate change and producing food on land that is not suitable for arable farming.
They need to be both preserved and managed better in order to provide multiple benefits to society — they will be important for future multifunctional agricultural landscapes. Contact: Regina Lindborg E-mail: regina.
Head of Department Georgia Destouni E-mail: georgia. Press contact Qiong Zhang E-post: qiong. Department of Physical Geography. To submenu. Research units. Resarch news archive. Ten reasons for preserving grasslands. Grasslands are important for water capture and flow regulation, and decreases risks for flooding. Temperate grasslands are the most endangered but least protected ecosystems on Earth.
Grassland restorations are crucial for recovering this important but highly degraded ecosystem. Restored grasslands, however, tend to be more species poor and lose diversity through time as compared to remnant, or never-been plowed, grasslands.
A new study from the University of Missouri found that milkweeds and other plants that have seeds carried by the wind are an important source for enriching the diversity of plants in these valuable ecosystems. They provide food for livestock, habitat for wildlife, prevent soil erosion, support pollinators, and capture a lot of the world's carbon.
These benefits derive primarily from the diverse grasses and flowering plants that comprise grassland communities. When we lose that diversity, we risk losing those benefits," said Lauren Sullivan, a grassland ecologist with the Division of Biological Sciences. Ecologists describe spillover as the natural movement of species from one habitat to another.
The concept is commonly associated with marine habitats, where fish spillover from protected areas can be used to improve adjacent fisheries. The grasslands provide feeding grounds for all manner of prey and predators and give balance to the world. The next time you drive by an open field, give it a second look and be happy to see the grass blowing in the breeze.
Whether it is being used for grazing or simply sitting as it is, the fact the land remains as a grassland is a good sign. Wildlife Heritage 83 Posts.
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. Similar calculations for higher forage systems than used in the USA, as practiced in countries like Ireland and New Zealand, would show higher efficiencies than in the data of Oltjen and Beckett , and would encourage higher utilization of grass and forage in ruminant production in place of grain.
This study compared energy and protein efficiency of milk and meat production in the USA and South Korea from both a total efficiency and humanly edible efficiency viewpoint. In both countries, the humanly edible efficiency of milk and beef production was higher than on a total efficiency basis.
However, while total efficiencies for protein and energy in milk and beef production were higher in the US than in South Korea, the opposite was the case when assessed on a humanly edible basis: the efficiencies were higher in South Korea than the USA.
Commenting on this study, Gill et al. In addition to the significant stocks of carbon, grasslands also contribute to climate change mitigation by sequestering additional carbon. However, there is considerable debate as to whether grassland carbon sequestration is finite with the time period required to reach a new equilibrium dependent on previous land-use and soil clay content. While some estimates of the time-scale for grassland carbon equilibrium range from 30 to 40 years Falloon and Smith, , other studies have shown that grasslands have a large potential to store additional carbon and may continue to act as a carbon sink for longer periods of time Poeplau et al.
Most of the technical mitigation potential identified by Smith et al. Grazing land management and pasture improvement was one of the options considered by Smith et al. There are a number of practices that could contribute to reduced greenhouse gas emissions and enhanced sinks in grazing lands. Both under and over grazing can lower carbon sequestration or lead to carbon loss from soils Rice and Owensby, ; Liebig et al.
The effects of grazing are mediated by changes in the removal, growth, carbon allocation and flora in pastures, and carbon input from ruminant excreta, which affect the amount of carbon in soils. Improving the productivity of pastures through practices such as fertilization and irrigation can improve carbon storage in pastures.
There can be some offsetting of these gains by nitrous oxide emissions from nitrogenous fertilizers and manures and the energy used in irrigation. A positive correlation between C sequestration and N fertilization has been observed in managed grasslands Jones et al. Matching nutrient addition to pasture requirements, thus avoiding excess applications which can result in unnecessarily high nitrous oxide emissions, can lead to a reduction in emissions from grasslands. This is obviously easiest in intensively managed pastures which receive nitrogen fertilizer or managed application of organic manure and more difficult in extensively managed pastures where the main nutrient additions are deposition of faeces and urine by grazing animals which are not as easily controlled.
Fire can be used to control and improve pastures, but it does cause increased greenhouse gas emissions, directly release of methane and nitrous oxide and indirectly ozone production, smoke aerosols, reduced albedo effect, and reduced tree and shrub cover causing a reduction in carbon stores in soil and biomass.
Reducing the frequency and extent of fires, reducing the extent of vegetation present when burning takes place and burning at a time of year when less methane and nitrous oxide are emitted will reduce emissions associated with burning pastures, although it has been reported that the area burned may be ultimately under climatic control Van Wilgen et al.
Enhancing species diversity and, in particular, introducing new deep-rooted grasses with higher productivity into the species mix has been shown to increase soil carbon, particularly on low-productivity pastures and savannahs Tilman et al.
While Smith et al. In addition, Smith et al. Practices which contribute to the restoration of degraded grassland such as planting grasses, improved fertility, application of organic manures, reducing tillage and retaining crop residues, and conserving water will increase soil carbon.
Much of this degraded land is pastures or former pastures. A key metric for the efficiency of food production systems in the context of its impact on climate change is the greenhouse gas emissions per unit of food produced. This should account for direct emissions from the system, and emissions embedded in inputs brought into the system or farm. Thus a life cycle assessment LCA methodology is appropriate when making such calculations. However, correct analysis of LCA depends on a use of the appropriate functional unit e.
In a recent study, milk production was compared across a number of types of systems and climatic zones FAO, The study was an LCA and included emissions associated with milk production, processing and transportation of milk and milk products. The study did not include emissions or sinks related to land use or land use change. It is likely that including a more comprehensive assessment of this including carbon sequestration under grasslands as discussed above would have improved the relative position of milk production from grassland systems.
Further, when emissions from temperate regions only are compared, the greenhouse gas emissions per kilogram FPCM were remarkably similar between grassland and mixed farming systems FAO, Another major study that was conducted recently compared food production across the 27 member states of the EU Leip et al.
Again it used an LCA to compare the greenhouse gas intensity of food production inside the farm gate. For milk production, the countries with the lowest emissions per kilogram of milk were Austria and Ireland, the latter having a very high rate of grass utilization in dairy cow diets O'Mara, It is interesting that nitrous oxide emissions from grazing animals and mineral fertilizer application were between three and four times higher in the Irish system than the Austrian data, but this was counterbalanced by lower nitrous oxide emissions from manure management and manure application and lower carbon dioxide emissions from electricity use, buildings and machinery.
This illustrates that grassland-based milk production can be as efficient as high-input systems from a greenhouse gas perspective. For beef production, it is more difficult to draw conclusions because of the multiplicity of beef production systems in the EU beef from dairy or beef cows, bull or steer production systems, differing ages at slaughter, etc. Again, Ireland has a very high level of grass utilization in beef production, and the emissions per kilogram of beef produced were amongst the lowest of the 27 EU countries studied by Leip et al.
However, the pattern of change is predicted to vary across a longitudinal and latitudinal gradient, with the highest increases in temperature and decreases in precipitation occurring in Mediteranean Europe, whilst precipitation is forecast to increase in northern Europe Parry et al. As a result, different responses in terms of grassland management and wider agricultural practices may be required, with increasing intensification focused on northern Europe and a trend towards extensification in southern regions due to resource depletion Olesen and Bindi, A shift to increased investment in root biomass allied to decreased decomposition rates can also lead to enhanced carbon sequestration under high CO 2 levels Van Ginkel et al.
This reduction in the rate of decomposition may be due to both higher C : N ratios of the plant material and alterations in microbial community structure under elevated CO 2 van Groenigen et al. Productivity gains resulting from future CO 2 levels may be negated by changing climatic factors, particularly increasing soil moisture deficits.
A combination of increasing surface temperature allied to prolonged drought periods can reduce primary productivity impacting on seasonal grass yields Bloor et al.
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