Conservation grazing

Conservation grazing is the use of semi-feral or domesticated grazing livestock to maintain and increase the biodiversity of natural or semi-natural grasslands, heathlands, wood pasture, wetlands and many other habitats. Conservation grazing is generally less intensive than practices such as prescribed burning, but still needs to be managed to ensure that overgrazing does not occur. The practice has proven to be beneficial in moderation in restoring and maintaining grassland and heathland ecosystems. The optimal level of grazing will depend on the goal of conservation, and different levels of grazing, alongside other conservation practices, can be used to induce the desired results. Conservation grazing is the use of semi-feral or domesticated grazing livestock to maintain and increase the biodiversity of natural or semi-natural grasslands, heathlands, wood pasture, wetlands and many other habitats. Conservation grazing is generally less intensive than practices such as prescribed burning, but still needs to be managed to ensure that overgrazing does not occur. The practice has proven to be beneficial in moderation in restoring and maintaining grassland and heathland ecosystems. The optimal level of grazing will depend on the goal of conservation, and different levels of grazing, alongside other conservation practices, can be used to induce the desired results. For historic grasslands, grazing animals, herbivores, were a crucial part of the ecosystem. When grazers are removed, historically grazed lands may show a decline in both the density and the diversity of the vegetation. The history of the land may help ecologists and conservationists determine the best approach to a conservation project. Historic threats to grasslands primarily began with land conversion to crop fields. However, this threat shifted to improper land management techniques and more recently to the expansion of woody species of plants due to a lack of management and to climate change. These threats hinder the ecological importance of grassland communities. Grasslands are a carbon sink, and benefit livestock. Ecologically, if managed properly, conservation grazing can help to restore these historic ecological assets. However, if the grazing levels reach too high, shrubs will persist over grassland. In 1985, the US established the Conservation Reserve Program (CRP), which gave money to farmers to leave land fallow, instead of using it for crops or grazing. It was argued that exclusion or use of moderate grazing would be an important factor in future decisions as to what to do with the land that was a part of the CRP program. The land could have varied uses in the future. The minimization of the effects of climate change has a lot to do with the sequestering of carbon, and expansive grasslands may play an essential role in this process. But also it could be used for the rotation of crops to the benefit of wildlife populations. The use of conservation grazing is dependent on what type of ecosystem, habitat, and plant community are desired to be maintained or restored. Grazing is a beneficial tool used to create a grass and small shrub dominated area. Tasker and Bradstock found that grazed areas returned a lower vegetation complexity score than ungrazed, however this was mainly because tree species and shrubs produce higher complexity scores than grasses – the grazed areas were composed primarily of bunch grasses and the ungrazed were dominated by shrub species. Certain areas that have been, historically, woody forest, may be chosen to be restored back to historical conditions, thus Tasker’s and Bradstock’s study would imply that wooded areas should remain ungrazed by livestock such as cattle. Conservation practices such as grazing need to be monitored closely. If they are not, the practice can become overused and have an opposite effect than intended. Overgrazing may cause erosion, habitat destruction, soil compaction, or reduced biodiversity (species richness). One issue of controversy with grazing is whether conservation grazing is in fact beneficial to a grassland community and what intensity of grazing management needs to be taken. Rambo and Faeth found that the use of vertebrates for grazing of an area would increase the species richness of plants by decreasing the abundance of dominant species and increasing the richness of rarer species. The decrease in abundance may lead to a more open forest canopy and more room for other plant species to emerge. Different grazing species have different effects. For example, elk and horses have a similar grazing frequency to cattle but tend to spread their zone of grazing to cover a greater area, producing a smaller effect on a given area than cattle would. Similarly, cattle have been found to be more useful in the restoration of pastures with low species richness, and sheep were found useful for the re-establishment of neglected fields. The type of area that needs to be restored or maintained will determine the species of grazer ideal for conservation grazing. Dumont et al. found in the use of varied breeds of steers that “traditional breeds appeared slightly less selective than commercial breeds”, but did not make a significant difference in biodiversity. In this particular study biodiversity was maintained by the same amount by both breed types. Conservation grazing is a tool used for conserving biodiversity. However, one danger in grazing is the potential for invasive species to be enhanced as well as the native biodiversity. A study by Loeser et al. showed that areas of high intensity grazing and grazer removal increased the biomass of nonnative introduced species. Both showed that an intermediate approach is the best method. The nonnatives did demonstrate that they were not as well adapted to the disturbances, such as drought. This indicated that implementing controlled grazing methods would decrease the abundance of nonnatives in those plots that had not been properly managed.