Protection and Management of Grassland Ecosystems

Because of overgrazing as well as rodent and insect pests, the grassland area in China is decreasing, and some pastures are facing the threat of desertification. Therefore, it is necessary to strengthen the rational utilization and protection of grasslands. Grassland ecosystem protection has attracted national attention, China's "Grassland Law" has been formally implemented since October 1, 1985, which is China's grassland status and role and grassland ecological environment deterioration of the harm of understanding has reached a new level of symbols, but also China's grassland ecosystems from the natural use of the scientific management of the beginning. Countermeasures for the protection and restoration of grassland ecosystems should especially focus on the following aspects: For climate change dominantly, many studies have shown that the magnitude of long-term climate change is much smaller than the impact of annual and seasonal changes on grassland ecosystems. At the same time, under the influence of global climate change, the general trend of climate in some regions shows fluctuation towards warm and wet direction, so it is difficult to attribute the degradation of grassland ecosystems in many regions to climate change.

For human activity interference, it is usually believed that overloading and overgrazing is the main cause of grassland degradation. However, many studies have shown that the overall year-round supply of grassland forage in many areas is basically equal to or in surplus with livestock feeding. And the seasonal imbalance of grass production and seasonal overloading and overgrazing, as well as seasonal grass-livestock conflicts are the main factors causing grassland degradation.

Through the case study on the impacts of grazing activities and climate change on the grassland ecosystem of the Sanjiangyuan, I believe that, although it is not yet possible to clearly distinguish between the roles and contributions of climate change and grassland management to the changes in the grassland ecosystems, the impacts of both should not be ignored.　　Grassland reclamation has also been recognized as an important cause of grassland degradation in many regions, but some studies have concluded that grassland reclamation is localized and limited in scale and extent, and is not sufficient to cause comprehensive and large-scale degradation of grasslands. On the other hand, some studies have shown that the abandoned grassland after reclamation has a strong self-recovery ability.

The indiscriminate exploitation of grassland by woodcutting is also limited in scale and extent compared with the impact of herbivorous livestock on grassland vegetation, and is limited to certain localized areas. It has been argued that the suitability of artificial grassland construction is now being expanded indefinitely, and that artificial grassland construction is being advocated in almost all areas of grassland livestock husbandry. In fact, artificial grassland construction requires many relatively strict conditions, such as geographic topography, soil texture, irrigation and precipitation, etc. In the arid regions of Northwest China, if these conditions are not available, the impacts of artificial grassland construction on the grassland ecological environment are likely to be negative.　　Pasture introduction problem of artificial grassland construction. In the construction of artificial grassland, unsuitable seed introduction has caused many ecological problems. Some people think that in the construction of artificial grassland, excessive emphasis on the introduction of foreign high-quality and high-yield forage grass, but ignored the suitability of the local indigenous wild forage grass resources, planting forage grass varieties of monoculture, resulting in the disorders of biodiversity, ecosystems, such as the original structure and function of the damage, the intensification of the grassland disease and pest, the change of zonal vegetation landscapes, soil erosion phenomenon intensified.

Water consumption of artificial grassland. Artificial grass in the high productivity of pasture grass often need high water and fertilizer with, and has the characteristics of high transpiration water consumption, so that the arid region of the soil water deficit intensified, years of continuous planting led to soil drying, the formation of biological soil drought, accelerate grass degradation. Some researches show that a cautious attitude should be taken when planting artificial grassland in areas with annual precipitation below 450 millimeters.　　The problem of cultivation method of artificial grassland. The construction of artificial grassland often adopts high-density cultivation method, and the cultivation density is too high, also due to the plants consume too much water leading to soil drying, community decline, and the yield drops sharply, which in turn causes the degradation of artificial grassland. First, "contract to household" and "joint production management" dispute: grass contract to household and the implementation of grass paid contract responsibility system is considered to be an effective policy to curb the degradation of grassland.

Contracting to the household has led to a sharp increase in grazing pressure on unfenced pastures and "public **** pastures", resulting in more serious grassland degradation.　　The current encouragement of "joint household management" in fact forms a negation of "contract to household".　　Seasonal mobile grazing is the main mode of grassland animal husbandry production in the northern region, and mobile grazing in a large spatial area has caused difficulties in the division of grassland and contracted to the household.

The second, rough and intensive dispute: intensive grassland animal husbandry production is the direction of modern grass development. However, some people believe that in some areas in the north and west of China, the intensive production mode is not the only choice. In arid and extremely fragile ecosystems, intensive production marked by human intensity intervention can easily cause ecosystem degradation with a little carelessness. In countries such as Australia and New Zealand, the inland arid areas also practice a rough business approach and do not promote intensive production.

Thirdly, the controversy between the restriction and waste of livestock: excessive number of livestock is considered to be the main cause of grassland degradation. But some people believe that in many areas, the grassland production potential and the total amount and the number of livestock is roughly balanced, and even in the warm season there is a large surplus, mainly in the pasture supply seasonal imbalance, the use of a broad-brush method of compression of the number of livestock, it is easy to cause a waste of resources.

The fourth, the operation of grassland and protection of grassland dispute: our traditional concept of grassland resources, especially emphasize the value of livestock production, so that the environmental conditions are extremely poor, the ecosystem is extremely fragile part of the desert and alpine grassland is also regarded as the base of the grassland animal husbandry production, which caused the inevitable degradation of the grassland. In fact, 58% of New Zealand's land is used for economic production, while 42% is used for ecological protection.

Fifth, the grassland carrying capacity dispute: some people think that the theory of grassland carrying capacity is difficult to be applied to arid and semi-arid grassland areas, this is because the climate change of arid and semi-arid grassland is very big, and its ecosystem functions as a non-equilibrium system, and its change is not to the top of the state of the certainty of the development, but is controlled by some unpredictable random factors. Some of the grassland degradation thought to be caused by overgrazing may actually be the response of grassland vegetation to changes in random factors such as climate. In addition, arid and semi-arid grasslands tend to form multiple, relatively stable "states" rather than a unique apex community in an inherently directed sequence.

Because of the non-linear nature of grasslands in arid regions, even if a "reasonable" grazing pressure is determined, it is not always possible to move from one state to another and ultimately reach a stable equilibrium. In arid areas, the influence of climate change is much greater than the regulation of livestock carrying capacity.　　On the other hand, the carrying capacity of grassland is calculated on the basis of the average annual productivity of grassland and the average feed intake of livestock, which is unreliable in arid areas with high seasonal and inter-annual variability. Meanwhile, for the northern nomadic mode of production, the spatial and temporal relationships of the grass-livestock system are very complex, and the average carrying capacity of a large region can hardly reflect the actual situation.

Sixth, the dispute between the planned nature of grassland management and "opportunism": some people believe that "opportunism" is the most appropriate ecological response in the system of severe and variable environmental stress. Unlike the principle of carrying capacity, which is based on average estimates, the opportunistic response enables pastoralists to take advantage of temporal and spatial changes in pasture volume to adjust livestock numbers in a timely manner. Thus, opportunistic responses require pastoralists to respond quickly to grazable opportunities, and herds need to be highly mobile and adjust quickly to grazing pressure as conditions change. And traditional nomadic pastoralism is, to some extent, an opportunistic response, an adaptation to specific environments and resources.

Seventh, the "grass for livestock" and "livestock for grass" controversy: some people believe that the "livestock for grass" is not scientific, in practice can not be realized, because only consider the ecological protection, ignoring the economic development. Ecological protection, ignoring the economic development; only consider the natural factors, ignoring the human subjective initiative, the result is contrary to the wish, so that the grass does not get due protection. Livestock to grass" is the development direction of animal husbandry, grass industry and ecological protection, which is conducive to mobilizing producers to build grassland and protect the environment under the economic objectives, and is conducive to the government's change of functions, and is conducive to farmers and herdsmen to improve the quality and efficiency of the products and ultimately to achieve sustainable development.　　Although currently in the academic community there are the above debates, some points of view is indeed worth thinking about, there are some points of view may be too biased, but are grassland ecosystem management and grassland production in the existence of practical problems, the need to step up efforts to solve.