Final answer:
Overgrazing is often due to poor livestock management where animals are allowed to roam freely without control over their numbers or grazing time, while clearing trees for construction contributes to deforestation and environmental degradation. Controlled grazing management can mitigate these issues.
Step-by-step explanation:
Practices that have led to overgrazing of grasses and shrubs, as well as the clearing of trees for fuel, include allowing animals to roam freely and clearing trees for construction. Overgrazing occurs when too many animals feed too long and exceed the carrying capacity of a grazing land area, which can lead to habitat degradation. This is often a result of poor livestock management where there is a failure to control the number of animals or the timing and duration of their grazing.
Clearing trees for construction not only removes vegetation that could be a food source for herbivores but also contributes significantly to deforestation. Livestock farming accounts for a substantial portion of all deforestation, leading to the loss of habitats for numerous species, the building up of greenhouse gases, soil erosion and changes in rainfall patterns. Controlled grazing management, on the other hand, involves practices such as rotating grazing areas and allowing for fallow periods, which can help prevent overgrazing and preserve grasslands.