Overgrazing represents an environmental hazard whereby wildlife or livestock excessively feeds on pasture. It is also the practice of grazing livestock on vegetation before it has recovered from a former grazing state, also known as intensive grazing. Otherwise stated, overgrazing takes place when vegetation or pasture is repeatedly removed from the land, and it is not given enough time to continue growing.
Intensive grazing thus causes the plant residual matter to decline and further contributes to numerous negative consequences to both the animals and the land. Consequently, overgrazing signifies a serious environmental challenge in maintaining the natural balance of livestock on grazing lands, which reduces the productivity, usefulness, and biodiversity of the land. The following are the causes, effects, and solutions of overgrazing.
Wikipedia defines Overgrazing as,
“Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature reserves. It can also be caused by immobile, travel restricted populations of native or non-native wild animals.“
Causes of Overgrazing
1. Lack of Proper Animal/Wildlife Management
The lack of proper animal and wildlife feeding management on the available pasture is the leading cause of overgrazing. From the definition, overgrazing arises as a result of having too many animals grazing on a piece of land without proper control of the grazing activity of the animals. The failure to rotate animals in harmony with pasture growth is what constitutes overgrazing.
For instance, without proper management of the animal’s feeding habits, they tend to feed on young plants and seeds, thereby reducing their growth and survival capacities. Besides, the lack of proper animal/wildlife grazing management destroys the soil’s nutrient composition, which further worsens the situation.
If the Mediterranean rangelands are taken into consideration, as claimed by Le Houerou, the mild and lightly rainy winters are to be blamed for the fact that through those months, domestic animals can bear to remain outside. When outside, they can easily graze on the nearest pasture, and once this activity goes unchecked and unnoticed, it is just a matter of short time that grazing will turn into overgrazing.
2. Socio-economic Conditions of the Farmer
Now that we have looked into the problem caused by improper management of livestock, we must also inspect another linked issue. The farmers handling the livestock generally belong to a weaker socio-economic background.
This means that they are unable to support their livestock with the proper amount of fodder and thus, but turning them onto pastures, leave them to fend for themselves.
3. Drought or Decline in Precipitation
Drought and the decline in precipitation in any area automatically mean that the growth and survival of plants and vegetation are heavily impacted. The direct outcome of this is stunted growth and drying out of plants/vegetation.
Accordingly, the risk of overgrazing is heightened in such areas subject to the insufficiency of forage. Examples include areas adjacent to deserts such as northern China, Pakistan, India, Patagonia, the drier regions of southern and northern Africa, and the prairies of Northern America.
4. Improper Land Use
Land use significantly determines the productive condition of the land and soil fertility. Hence, improper land use such as logging activities, slash and burn farming techniques, mining, excessive and unplanned urban sprawl, and land pollution lessens the overall land available for pasture.
All these activities greatly impact the availability of plants and forage by destroying their underlying growth support mechanisms. In most cases, these activities are characterized by an increase in unpalatable plants or weeds and a decrease in plant humus that increases the potential of the overgrazing problem.
Overstocking implies a situation where a piece of land is intensively stocked with more animals that the site can support for a grazing season. In the majority of the cases, animals are more than the average land available for grazing, which leads to repeated removal of plant/vegetation material without a sufficient amount of time given for the leaf/pasture mass to regrow.
Put differently, farmers who overstock do not let the average land replenish itself after a previous grazing season. Eventually, overgrazing is experienced.
6. Poor Irrigation Methods in Arid and Semi-arid Areas
Incorrect irrigation techniques in arid and semi-arid regions cause accumulation of salt in the soil. As an outcome, the availability of palatable plants is impacted because of the alteration of soil’s mineral content composition. The buildup of salts in the soil also leads to stunted growth, reducing the availability of forage.
The few remaining good pasture lands are hence heavily utilized, creating room for overgrazing. The problem is further exuberated by the fact that poor irrigation practices are common in poorer and ASAL regions.
Prolonged Effects of Overgrazing
1. Soil Erosion
The continued trampling of numerous animals in an average forage land will act to accelerate the death of plants and vegetation cover. This is because the animals will graze even on the slightest shoots of new growth.
Without the plants or vegetation cover, the soil is left bare and exposed to harsh weather such as heavy downpour and high temperatures, which disintegrates the rocks and carries the topsoil away.
Animals also prefer gathering at specific areas, like next to water sources, and such areas can get eroded.
2. Land Degradation
The acts of compaction and erosion as a result of overgrazing can cause tremendous land degradation. In drier areas, the experience is even worse as a large percentage of pasture and land cover is destroyed, contributing to the relentless progression of desertification.
In fact, in some areas overgrazing has led to complete desertification. Overgrazing combined with overstocking has the most damaging outcomes to the world’s natural environment.
The scarcity of water resources, water pollution, degeneration of coral reefs, and eutrophication are all connected to overgrazing. The chief polluting elements include farm chemicals and animal wastes.
Intensive grazing disrupts the water cycle and diminishes the replenishment capability of groundwater resources as substantial amounts of water is used for feed production. In the South China Sea, overgrazing is linked with nitrogen and phosphorous contamination.
3. Loss of Valuable Species
The natural composition of the plant population and their regeneration capacity is significantly affected by overgrazing. The original pasture crops are composed of high-quality pastures and herbs with great nutritional value. When animals intensively graze on such pastures, even the rootstocks which contain the reserve food or regeneration capacity get ruined.
Once ruined, some other more adaptable species, such as weeds and unpalatable plants, take up their place. These secondary plant species have less nutritional values, and because they are highly adaptive, they replace the native species, thereby causing the loss of valuable plant species.
4. Food Shortage/Famine
As earlier stated, overgrazing is a primary contributor to desertification because it converts arable or pasture land into unproductive piece land. The resultant soil is thus not suited for growing food since it loses its essential nutrients.
The loss of land productivity directly results in the loss of food available for consumption. This heightens food supply reduction, and if population growth is still registered, it causes starvation and economic challenges.
5. Death of People and Livestock
The long term effects of overgrazing are food shortage, which can make people and cattle die of starvation. Without sufficient pasture for livestock grazing, cattle lack the necessary nutrients for survival. The nutrient deficiencies make the animals unable to gain weight appropriate to their productive stage and life, which lowers their chances of survival.
Human survival levels, well-being, and health are as well affected when there is an inadequate food supply for consumption. The end results are acute starvation and the death of both people and livestock.
It comes as no surprise that overgrazing causes deforestation as well. With the animals feeding on all the foliage covering and protecting the soil, it is only natural that the lack of foliage would leave the soil completely bare.
Not only that but the soil erosion that this barrenness causes can render the soil in that area completely infertile, and the growth of any further foliage might turn out to be impossible.
7. Global Warming
With deforestation comes another threat called global warming. With the foliage gone, a percentage of carbon dioxide absorption is also gone. Thus, as a result, carbon dioxide levels increase on the earth’s surface, which, in turn, traps the heat of the short rays of the sun. This leads to an increase in the mean temperature of the earth’s surface, making the earth a hotter place to live in!
Simple Solutions to Overgrazing
1. Proper Management of Animals
As much as overgrazing is associated with the number of animals, it’s more about the management of the animals. There are several methods of grazing management to choose from that can offer effective solutions to overgrazing. Examples are rotational, cell, and mob grazing.
It is simply up to those in charge of grazing to take appropriate measures in ensuring that these management practices are effectively utilized.
Each grazing management technique is tailored to meet the different situations and if well utilized, it can strongly assist in restoring the plant-growth during the entire year. Proper management of animals also bears the potential of wholly enhancing grazing land conditions via improved pasture production and soil health.
2. Land Use Management
Land use management involves the proper assessment of various land uses and the implications of human activities on land. Local and regional factors such as aridity and rainfall patterns also have to be considered before any land development or exploitation implementations are undertaken.
Proper urban planning and industry setup has to be in accordance with up to date environmental policies on sustainable urbanization, industrial construction, and agricultural practices.
This avoids the over-utilization of available arable land and green pastures and enables easier control policies on overstocking. The use of soil conservation measures and silvopastoralism, in conjunction with controlled livestock restriction from sensitive areas and payment schemes for livestock-based land use, can also help cut down and reverse the effects of overgrazing.
3. Sustainable Pasture Practices
Sustainable pasture practices pertain to grassland production in a well managed and controlled manner. The concept is simply based on grassland management, animal management, land management, and livestock marketing.
When grazing management is combined with agroecology practices and sustainable agriculture, it gives rise to the most suitable grassland-based livestock production because it encourages both animal and plant productivity and good health.
Some of the novel and impressive sustainable grazing models and management systems that try to lessen or end overgrazing include permaculture and holistic livestock management.
4. Shifting to Other Ways of Feeding Livestock
It is essential to understand that livestock can be fed on stored fodder as well. This process not only ensures the fact that the livestock does not overfeed, but it also ensures that pastures are not overgrazed. This is yet another sustainable practice that could be adopted.
The solutions to overgrazing can be summarized as follows:
- Avoiding the act of grazing too early, you can have the stockpiled in the rainy season (spring) so that there is enough grass in the dry periods (summer).
- The use of a grazing chart can assist in planning out how to implement rotational grazing.
- Monitoring rainfall patterns and the growth of pasture.
- Maintaining and managing proper pasture residuals in the grazing area.
- Making sustainable pasture management decisions in dry weather conditions, this can be achieved by learning more and more about sustainable pasture practices.
- Proper land use management practices.
- Trying to feed livestock with stored fodder.
- Controlling the amount of time that livestock spends on the pastures.