We spend a lot of time talking to client's about the beneficial aspects of grazing, as this relates to fire and fire ecology. But grazing when mismanaged or utilized inappropriately can actually shift species composition from a fire resistant to a fire prone environment.
As a rule, grazing can either promote or surpress certain types of vegetation. Targeting certain species of plants and vegetation is fundamental to shifting vegetation type. Type I or "light fuels" are more palatable to grazers during the early to late spring and can therefore be targeted during these periods. As a result of targeting these "light fuels" other types of fuels will persist.
Gradually, if only Type I fuels are targeted, the composition of the vegetation will shift towards the other types of fuels that have note been targeted.
In a managed grazing setting this propensity for the fuel type to shift is undertoood and used intentionally to shift an ecotone from fire prone to fire resistant. When grazing is applied without this understanding the results can be arbitrary at best. More often the result of mismanaged or unmanaged grazing is increased fuel loads with a gradual shift towards "heavy fuels" and more fire prone environments.
Grazing is a tool and also a fundamental component of many ecosystems. In a natural setting grazers are matched to their environment through evolutionary partnership where both grazer and the vegetation exist in symbiotic harmony. The grazer requires nutrient rich plant material while the plants require disturbance in the form of the grazer. If either component of this system is missing or disrupted, imbalance is the result. Similar imbalances evolve when grazing is applied without understanding.
There are many levels of complexity in ecosystems and grazing is often a viable solution. However, grazing is one of a handful of tools that we can use to move environments towards sustainability. Like any tool we need to understand how and when to use it properly.
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