1: Introduction of overgrazing
Overgrazing takes place when plants are unprotected to thorough grazing for total period of time or without enough recovery periods. It is caused by when livestock is poorly managed the agriculture application like Game reserve or nature reserve. It can also caused by unmoving, travel limited population of native or non native wild animals.
Cows are the important things that cause the overgrazing and overgrazing. Overgrazing is based on the equilibrium theory (Laduke, Winona 1999).
Fig 1.1 overgrazing
2: Causes of overgrazing
There are many causes of overgrazing some are man- made and other are not able to avoid. Man –made overgrazing occur when owner become irresponsible. They do not care their land they allow the wild animals to travel freely in their land. There are some causes are discuss below.
2.1: Improper animal management
This is the important cause of overgrazing. Overgrazing occur when farmer have lager amount of animals and they graze over the piece of land without any control on grazing activity. Animals are graze over the same piece of land these cause the overgrazing. They have improper management of animals feeding habits, the animals feed on small plant and seeds they decrease their growth and survival rate. The improper management of animals damage soil nutrients.
Drought is the common cause of the overgrazing in over the world. Framer can’t control the rain and total drought repeatedly indicates that the domestic animals are grazing on vegetation that would not be regained. When plants and grass will die and they leave few choices for domestic animals in area. Framers animals feed on the plants that exist but the rain can’t fall for the regain of crops and any kind of plants or grass and animals can’t be regain. The danger of overgrazing is increase in some areas where to control the feed.
Adjacent to desert like northern China, Pakistan, India, Patagonia, the dry region of southern and northern Africa, and prairies of northern America.
Fig 1.2 Droughts
2.3: Improper land use
Land is used to analyze the yield of the land and the abundance of the soil. Improper use of land includes the logging, slash, and burn farming process and land pollution all land procurable for vegetation. These processes destroy the availability of plants and food and destroy their growth mechanisms also. They decrease the growth of plant and increase the chances of overgrazing.
When farmer have livestock for grazing area. The large population of animals destroys the vegetation in area before it can regain. Animals destroy the area and there are no plants for feeding thy lead to cause the overgrazing. Plants require time for their regrow after animals feed on them and too many animals are present on the small land that causes the overgrazing.
2.5: Poor irrigation method in arid and semi-arid areas
They increase the addition of salt in the soil. The edible plants are found because of different soil and mineral composition. The rich amount of salt in soil stops the development of plant and decrease the food source. Good land of vegetation is more used and creating room for over grazing.
They are common in poorer and ASAL region (C.Michael Hogan .2009).
3: Indicators of overgrazing
One indicator is that the animal runs in the small area of grass. Continuous overgrazing takes place in some region of United States, overgrazed pastures are prevailed by short grass species for example bluegrass and will be under 2-3 inches tall in the grass area, in other part of the world overgrazed field is regularly tall than maintainable grass field, the grass height is normally 1 meter and dominated by inedible species of plants, for example Aristida or Imperta. And some are edible tall grass for example orchard grass does not exist. In some cases of the overgrazing soil may be visible between plants and in the stands they allow the erosion to occur but in some cases overgrazed field covered the surface of the ground that contain the grass and grass root than maintainable grass field.
3.1: Rotational grazing
The overgrazed plant has not sufficient time to attain their normal height between grazing events. The animals restart grazing before the plant restored carbohydrates retain and its growing roots lost after the defoliation. The result is similar to the continuous grazing in the United State the tall-growing species die and short-growing species is more able to lack the injury majority in the grazing land and in the other part of the world the tall and lack tolerant inedible species of the plant for example Imperata or Aristida.
3.1.1: North America
Other indicator of overgrazing found in the North America is the domestic animals move in the field and animals need to feed in this region for its survival and its climate rule is different from the United State.
Overgrazing is also verified in the animals act and its condition. Cows have insufficient field directly following their calf’s weaning have poor body conditions in following seasons. This may decrease the health and strength of cows and calves at calving or birthing. When cows in poor body conditions don’t cycle as not long after giving the birth to the baby cow that cause the slow breeding. And its result in long calving season. The good genetic material, nutrition, and ideal seasons and controlled breeding 55% – 75% of calves should come in 21 first days of calving seasons. The poor weaning weight of the baby cow can be occur by low area of field. When the cow give less milk the baby cow maintain their weight by feed on the grass field (Garrett Hardin, December 13, 1968).
4: Ecological impacts
There are many ecological impacts that cause the overgrazing. These are given below one by one.
4.1: Soil erosion
This is the 1st and important effect of overgrazing on the environment. Animals continuously feed on the vegetation and they exposed the soil surface and no plants are left that protect the soil. Soil faces the harsh environmental conditions. For example heavy rain and direct sunlight. The regular trampling related with cultivating animals that rapidly cause the loose of vegetation. When the small plants grow and the animals feeds on these small plants and exposed the soil. Without giving any chance to the newly developed plants the animals feed on them.
Fig 1.3 Soil erosion
4.2: Land degradation
Unbelievable land degradation is caused by soil erosion. The large amount of the grass field area is destroyed and they cause the desertification. But in some regions overgrazing cause the complete desertification. Natural environment is distributed by the overpopulation of animals and cause the overgrazing. The shortage source of water, water pollution, degeneration of the coral reefs and eutrophication are all related with overgrazing. The pollution is caused by using of chemicals and waste of animals. The continuously grazing disturbed the water cycle and decrease refill ability of ground water resources as large amount of water is used for feeding. In South China Sea overgrazing is related to nitrogen and phosphorous contamination. Because this water contains high concentration of nitrogen and phosphorous.
Fig 1.4 Land degradation
4.3: Loss of valuable species
The natural population of plants and is regain capacity is affected by the overgrazing. The original field of crops is consists of high value field and herbs with great nutritional value. The animals continuously feed on the valuable species and they even eat the roots (roots contain the stored food) of that species and their region ability is completely lost and we loss the important species of plants due to overgrazing. For example weeds and inedible plants take their place. Some species of the secondary plants contain the low nutritional value and they are highly adaptive to the native species cause of valuable plant species.
4.4: Food shortage / famine
This is the low-level case of overgrazing. Food shortage is the primary contributor to desertification they change the grass filed into the infertile land. And this type of soil is not fit for growing food because this land lost the entire essential nutrient that is required for the plant growth. When the ability of soil is lost and the land is not able to grow the food. If the population growth is increase they cause the overgrazing.
The increasing population needs more foods and need more space for its survival. Overpopulation, overgrazing and urbanization, related with one another and harm the environment. We don’t have enough space to grow our food and overgrazing destroys the space that we have left.
4.5: Death of people and livestock
The long effect of the overgrazing reduced the food supply and there is no food for the cattle and the people and this kind of situation cause the death of both due to hunger. When the improper supply of the nutrient in the field the animals do not able to maintain their weight at production stage and decrease the chance of survival rate. When the population of the human is high the rate of food consumption is also high and supply of the food is decrease. Shortage of the food supply causes the death of plants and animals (Duval, April 13, 2015).
Fig 1.5 Death of people and livestock
5: Preventing overgrazing
5.1: Preventing man-made overgrazing
Accept able grassland manufacturing is based on the grass and grassland management, land management animal management and animal selling. Grazing management was acceptable with agriculture and agroecology perform is the organization of grassland based animal productivity affect the both plants and animals health and its production. There are some new models have developed to managed or decrease the overgrazing. For example Holistic management and permaculture.
5.2: Responsible livestock management
The farmer did not care about the irresponsible behavior of the overpopulated animals. Many animals present in small part of the land and they feed on the plants that present in small parts and cause the overgrazing and also cause the desertification. Avoiding of overstocking is relatively easy process. Small Responsible livestock management have small difficulty, because the face the small problem about its learning and apply process they did not know the exacting area where the management is applied. There are different methods is used to recycle the livestock. If you take good steps for the plant development and they develop throughout the year and decrease the overgrazing. Nature will take care the land for you.
5.3: Farming responsibly
There are many environmental factors that contribute to the overgrazing, but some are man-made. Some farmer has many animals and these animals feed on the small region and they have no idea they destroy the all cultivation from this region and this process is called the overgrazing. One of the Farming methods is responsible for overgrazing. We can’t ignore the droughts and dry spells and we can’t control the overpopulation of the animals and many other factors cause the overgrazing.
5.4: Proper land assessment
Assessing condition of land is one of the necessary ways we can ignore and store the effect of overgrazing. Developers need to analyze the environmental factors of the area before making the house. We work together to make sure that we find particular area where is no more plants is present is the large amount of plants is present we destroyed these plants for our benefits. We only need the space or area for live and we do not need we go the green field area and destroy it for making the house (Holistic land Management, 20 December 2012).